Featured scientists: Interview with the winners of the Brazilian Award for best doctoral theses.

The list of the winners of the 2018 Capes Thesis Award was announced earlier this month. The award is given by Capes (the Brazilian federal government agency that is responsible for quality assurance in postgraduate courses in Brazil). It distinguishes the authors of the best doctoral theses defended in 2017 in postgraduate programs of Brazilian institutions. The awards ceremony will take place on December 13 in Brasilia.

The B-MRS Bulletin interviewed some of the winners, who were rewarded for their work on materials topics. Meet these young PhDs and their works.

Interview with Andrey Coatrini Soares, winner of the award for the best thesis in the area of Materials.

  • Thesis: Nanostructured films applied in biosensors for the early detection of pancreatic cancer. Available at http://www.teses.usp.br/teses/disponiveis/18/18158/tde-30032017-080111/pt-br.php
  • Author: Andrey Coatrini Soares.
  • Advisor: Osvaldo Novais de Oliveira Junior (São Carlos Institute of Physics of  USP – IFSC-USP).
  • Institution: Postgraduate Program in Materials Science and Engineering of the University of São Paulo (USP).
Andrey Coatrini Soares
Andrey Coatrini Soares

Andrey Coatrini Soares (born in Aguaí – SP, 33 years old) began increasing research experience in her first undergraduate year in Physics at USP, when he began his scientific initiation stage, which ended when he got his degree in 2010. He then decided to pursue a master’s degree and later a doctorate, both in the program in Materials Science and Engineering of USP. All along those years, he had the guidance of Professor Osvaldo Novais de Oliveira Junior, and worked with nanostructured films with applications in the health area. “Embracing a scientific initiation stage in the first undergraduate year and being able to work with researchers who are references in the field was crucial to accumulate experience in the area of the thesis subject,”  says the Capes Award winner who continues to work with nanostructured films for health, now as a postdoctoral fellow at IFSC-USP.

In his doctoral research, Soares developed a low-cost sensor, made from renewable materials, which detects pancreatic cancer in 8 minutes. The research was carried out in the Prof. Bernhard Gross Polymer Group of IFSC-USP, in partnership with the Molecular Oncology Research Center of the Cancer Hospital of Barretos, and with the Microfabrication Laboratory of the National Center for Research in Energy and Materials (CNPEM). “The combination of experience in the clinical area of the Barretos team, experience in the area of photolithography/devices of the CNPEM team and the experience in biosensors and thin films of the São Carlos team allowed a rigid selection of what types of materials would be used , the types of devices to be tested and, mainly, which type of cancer would be detected,” says Soares.

B-MRS  Newsletter: In your opinion, what is the most relevant contribution of the award-winning thesis?

Au interdigitated electrode functionalized with Anti-CA-19 antibodies for early detection of pancreatic cancer.
Au interdigitated electrode functionalized with Anti-CA-19 antibodies for early detection of pancreatic cancer.

Andrey Coatrini Soares:  The major problem for the diagnosis of pancreatic cancer is the silent characteristic of the disease; that is, the tumor is only detected at an advanced stage. Therefore, this type of cancer has the highest mortality rate among all cancers (99.3%, according to the International Agency for Research on Cancer, IARC). In addition, the current cost of the commercial diagnosis plus the detection time (approximately 40 minutes) are not allies of the patient. These were the key factors that led to our choice to develop a low-cost, low-speed miniaturized biosensor that could be implemented in clinics and hospitals, allowing clinicians, for example, to make decisions about patient care or analysis the efficiency of chemotherapy without the need to use invasive diagnoses.

B-MRS Newsletter: Cite the main results generated from the award-winning thesis.

Andrey Coatrini Soares: The work of the doctoral thesis developed a low cost diagnosis using biocompatible and biodegradable materials from renewable sources such as chitosan (found in shrimp exoskeleton) and concanavalin A (protein extracted from the seeds of Breadfruit). The versatility of these biosensors allows them to be implanted in patients for real-time screening of the biomarkers that are present in the blood. Each test costs R$ 5.00-6.00, which detects pancreatic cancer in just 8 minutes, using only 10μL of blood.

The thesis was also honored with the USP 2018 Thesis Highlight in the multidisciplinary area. It also has generated, to date, two papers published in the journals ACS Applied Materials and Interface and Analyst, an article in preparation, and 5 more works in collaboration with researchers who participated in the thesis, which report the development of other biosensors for the detection of breast cancer, head and neck cancer and HPV. These results have been widely disseminated in the media (Portal G1, FAPESP Research Magazine, FAPESP Agency, Portal Onconews,). In addition, a patent is under development and will be deposited in the future. The works are listed below:

  • Soares, A. C.; Soares, J. C.; Shimizu, F. M.; Rodrigues, V.C.; Awan, I.T.; Melendez, M.E.;  Piazzetta, M.H.O.; Gobbi, A.L.; Reis, R.M.; Fregnani, J.H.T.G.; Carvalho, A. L.; Oliveira Junior, O. N. A simple architecture with self-assembled monolayers to build immunosensors for detecting the pancreatic cancer biomarker CA19-9. Analyst 2018, 143, 3302-3308.
  • Soares, A. C.; Soares, J. C.; Shimizu, F. M.; Melendez, M. E.; Carvalho, A. L.; Oliveira, O. N. Controlled Film Architectures to Detect a Biomarker for Pancreatic Cancer Using Impedance Spectroscopy. ACS Appl. Mater. Interfaces 2015, 7 (46), 25930–25937. DOI: 10.1021/acsami.5b08666
  • Soares, A. C.; Soares, J. C.; Rodrigues, V.C.; Follmann, H. D. M.; Arantes, L.M.R.B.; Carvalho, A. C.; Melendez, M.E.; Reis, R.M.; Fregnani, J.H.T.G.; Carvalho, A. L.; Oliveira Junior, O. N. Microfluidic-Based Genosensors to Detect HPV16 in Head and Neck Cancer. ACS Applied Materials and Interfaces 2018.
  • Thapa, A.; Soares, A. C.; Soares, J. C.; Awan, I. T.; Volpati, D.; Melendez, M. E.; Fregnani, J. H. T. G.; Carvalho, A. L.; Oliveira, O. N. Carbon Nanotube Matrix for Highly Sensitive Biosensors To Detect Pancreatic Cancer Biomarker CA19-9. ACS Appl. Mater. Interfaces 2017, 9 (31), 25878–25886
  • Rodrigues, V.C; Comin, C. H.; Soares, J. C.; Soares, A. C. et al. Analysis of Scanning Electron Microscopy Images To Investigate Adsorption Processes Responsible for Detection of Cancer Biomarkers. ACS Appl. Mater. Interfaces 20179 (7), 5885-5890.
  • Soares, J. C.; Iwaki, L. E. O.; Soares, A. C. et al. Immunosensor for Pancreatic Cancer Based on Electrospun Nanofibers Coated with Carbon Nanotubes or Gold Nanoparticles. ACS Omega 2017, 2 (10) 6975-6983.
  • Soares, J. C.; Soares, A. C.; Raymundo-Pereira, P. A. et al. Adsorption according to the Langmuir–Freundlich model is the detection mechanism of the antigen p53 for early diagnosis of cancer. RSC Phys. Chem. Chem. Phys. 2016, 18, 8412-8418.
  • Soares, J. C.; Shimizu, F. M.; Soares, A. C.; Caseli, L.; Ferreira, J.; Oliveira, O. N. Supramolecular Control in Nanostructured Film Architectures for Detecting Breast Cancer. ACS Appl. Mater. Interfaces 2015, 7 (22), 11833–11841.

B-MRS Newsletter: From your point of view, what are the main factors that led to this outstanding research work at the national level (your thesis)?

Andrey Coatrini Soares: Teamwork, full dedication, in addition to funding from CAPES and FAPESP! In our work we had the participation of 12 researchers/collaborators in different areas of knowledge, from material engineers, chemists, physicists, physicians, geneticists and biologists. My sincere thanks to all of them: Prof. Osvaldo Novais de Oliveira Junior, my advisor and mentor, Dr. Juliana Coatrini Soares, Dr. Valquiria da Cruz Rodrigues, Dr. Flavio Makoto Shimizu, Dr. Maria Helena Piazzetta, Dr. Rui Murer, Dr. Angelo Luiz Gobbi, Dr. Matias Melendez, Dr. Lidia Rebolho Arantes, Dr. Rui Reis, Dr. José Humberto Fregnani and Dr. André Lopes Carvalho, as well as Dr. Rodrigo Marques de Oliveira and André Brisolari, responsible for guiding the first steps in science. The national emphasis achieved by the work is the result of the effort by the entire team, competent and cohesive, that to a certain degree strives to return to the population the investment made in our training, through a product that is accessible to all layers of society.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

Andrey Coatrini Soares: Joining the academic arena means to be aware that virtually all learning will be built primarily by the questions you will ask, the mistakes you will make in trying to answer them, and how you will handle the challenges that the work will impose on you. It is within this growth that we learn to deal with the daily pressure for results and to face all the technical obstacles of the work. Undoubtedly, the satisfaction of overcoming each obstacle together with the satisfaction of contributing to science in a country that does not value researchers overcomes all the difficulties experienced during the doctoral period. Therefore, valuing each moment of individual or group work, every conversation with the advisor and, above all, valuing one’s achievements, even if they are minimal, is very important. And never leave behind the moments of leisure!

Interview with Bruno Ricardo de Carvalho, winner of the award for the best thesis in the area of Astronomy/Physics.

Bruno Ricardo de Carvalho
Bruno Ricardo de Carvalho

Bruno Ricardo de Carvalho (born in Cuiabá – MT, 29 years old) has always liked optics. When he was a child, he wanted to know why the sky is blue, how the rainbow is formed…. However, until a few years ago he had not imagined he would become a PhD in optical spectroscopy.

Carvalho holds a degree and a Master’s degree in Physics from the Federal University of Mato Grosso (UFMT). During the master’s degree, guided by professor Jorge Luiz Brito de Faria, he began to study two-dimensional nanomaterials through computational simulations. Influenced by the desire to analyze these materials experimentally, he decided to undergo a doctorate at the Federal University of Minas Gerais (UFMG) under the guidance of Professor Marcos A. Pimenta, who was the author of interesting articles Carvalho had read regarding nanomaterials analysis by the Resonant Raman Spectroscopy technique. Thus, working in the Raman Spectroscopy Laboratory of UFMG, Carvalho obtained the main results of the awarded thesis.

As soon as he started his doctorate, Carvalho showed interest in an internship abroad to learn about interaction with other research groups, and he expressed it to his advisor. Thus, upon completing two years of his doctorate, Carvalho moved to the city of State College in the United States, where he spent a year participating in several research projects on two-dimensional materials and their applications, at the State University of Pennsylvania under the guidance of professor Mauricio Terrones. “It was a very demanding year of total dedication and focus, but also very productive,” says Carvalho, recalling the articles generated during this period and published in high impact periodicals, the dissemination of results in international sites and the collaborations with theoretical and experimental research groups. Currently Bruno de Carvalho is an adjunct professor at the Department of Theoretical and Experimental Physics of the Federal University of Rio Grande do Norte (UFRN).

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

Molecular model of a MoS2 monolayer excited by a green laser. The red light after the electron-phonon interaction.
Molecular model of a MoS2 monolayer excited by a green laser. The red light after the electron-phonon interaction.

Bruno Ricardo de Carvalho: The main contribution is the double resonance model that we proposed to explain a Raman band, known as 2LA in MoS2, which is originated by a process of scattering between valleys. The new model presented to explain such a process can be extended to other two-dimensional systems. This was an open topic for more than 30 years in the scientific community, in the case of the material studied in the thesis, and we were able to propose an explanation.

B-MRS Newsletter: Cite the main results generated from the award-winning thesis.

Bruno Ricardo de Carvalho: In the thesis we wanted to demonstrate that we had a specific problem and that we solved. Thus, the study of resonant Raman spectroscopy in MoS2 was the focus of the doctoral thesis. This work generated the two main articles of the thesis.

  • Carvalho, Bruno R.; Malard, Leandro M.; Alves, Juliana M.; Fantini, Cristiano; Pimenta, Marcos A.; Symmetry-Dependent Exciton-Phonon Coupling in 2D and Bulk MoS2 Observed by Resonance Raman Scattering. Physical Review Letters 114 (13), 136403 (2015).
  • Carvalho, Bruno R.; Wang, Yuanxi; Mignuzzi, Sandro; Roy, Debdulal; Terrones, Mauricio; Fantini, Cristiano; Crespi, Vincent H.; Malard, Leandro M.; Pimenta, Marcos A.; Intervalley scattering by acoustic phonons in two-dimensional MoS2 revealed by double-resonance Raman spectroscopy. Nature Communications 8, 14670 (2017).

Other papers that were also mentioned in the thesis:

  • Pimenta, Marcos A.; del Corro, Elena; Carvalho, Bruno R.; Fantini, Cristiano; Malard, Leandro M.; Comparative Study of Raman Spectroscopy in Graphene and MoS2-type Transition Metal Dichalcogenides. Accounts of Chemical Research 48 (1), 41-47 (2015).
  • Feng, Simin; dos Santos, Maria C.; Carvalho, Bruno R.; Lv, Ruitao; Li, Qing; Fujisawa, Kazunori; Elías, Ana Laura; Perea-López, Nestor; Endo, Morinobu; Pan, Minghu; Pimenta, Marcos A.; Terrones, Mauricio; Ultrasensitive molecular sensor using N-doped graphene through enhanced Raman scattering. Science Advances 2 (7), e1600322 (2016).
  • Carozo, Victor; Wang, Yuanxi; Fujisawa, Kazunori; Carvalho, Bruno R.; McCreary, Amber; Feng, Simin; Lin, Zhong; Zhou, Chanjing; Perea-Lopez, Nestor; Elias, Ana Laura; Kabius, Bernd; Crespi, Vincent H.; Terrones, Mauricio; Optical identification of sulfur vacancies: Bound excitons at the edges of monolayer tungsten disulfide. Science Advances 3 (4), e1602813 (2017).

B-MRS Newsletter: From your point of view, what are the main factors that led to this outstanding research work at the national level (your thesis)?

Bruno Ricardo de Carvalho: The infrastructure of the laboratory and of the institution where I conducted the research was fundamental to develop the work. The discussion with my mentors and the collaboration regime, made the work more robust and elegant, that is, when people from different points of view work together.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

Bruno Ricardo de Carvalho: My message is that they dedicate themselves to what they do. The doctorate is a phase of intense learning and dedication. To do science is to have a systematic posture, an open mind, a critical posture and spend many hours in the laboratory. All of this, with effort and dedication, generates work that will be recognized. And, much more than that, it will be work that you did and in my opinion this is the greatest satisfaction.

Interview with Henrique Bücker Ribeiro, winner of the award for the best thesis in the area of Engineering IV.

  • Thesis: Raman spectroscopy in two-dimensional materials. Available at: http://tede.mackenzie.br/jspui/handle/tede/3485
  • Author: Henrique Bücker Ribeiro.
  • Advisor: Eunézio Antonio de Souza (Mackenzie Presbyterian University).
  • Coordinator: Marcos Assunção Pimenta (Department of Physics, Federal University of Minas Gerais – UFMG).
  • Institution: Graduate Program in Electrical and Computer Engineering, Mackenzie Presbyterian University.
Henrique Bücker Ribeiro
Henrique Bücker Ribeiro

Henrique Bücker Ribeiro (born in Belo Horizonte, MG, 36 years old) was a student of the Physics bachelor’s degree at the Federal University of Minas Gerais (UFMG), when, in 2004, he started to analyze low-dimensional materials (those ranging from 1 atom to a few nanometers of thickness) using the Raman spectroscopy technique. Within a scientific initiation stage, guided by Professor Marcos Pimenta, he studied carbon nanotubes. In addition to guiding Ribeiro early in his career, Professor Pimenta introduced two professors from the Mackenzie Presbyterian University, Eunézio Antonio de Souza and Christiano José Santiago de Matos. “They played and play until now, alongside Marcos, irreplaceable roles as mentors and friends,” says Ribeiro.

From that contact, in 2014, Ribeiro began his doctorate at Mackenzie. There, he continued to study low-dimensional materials using Raman spectroscopy. Ribeiro started with bi-layered graphene and then continued with black phosphorus and monochalcogenides. In addition to the infrastructure at Mackenzie, Ribeiro used equipment from UFMG, CTNnano (Belo Horizonte), LNNano (Campinas), as well as computing centers from Unesp and Unicamp. Ribeiro’s thesis did not only generate knowledge about the studied materials, but also helped to improve the use of the Raman technique to probe this type of materials. Today, Ribeiro is in a postdoctoral program at Stanford University with the help of a FAPESP grant, where he continues to study low-dimensional materials, more precisely, optoelectronic processes of two-dimensional semiconductors.

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

Henrique Bücker Ribeiro: I believe that the most important contribution of the thesis was to explain an unexpected effect observed when measuring the angular dependence of Raman spectra on black phosphorus. We were able to explain with this study that when analyzing the angular dependence of the Raman spectra for certain crystals, it is necessary to consider an unusual mathematical treatment. This work has become an important reference for researchers working with low dimensional materials similar to black phosphorus.

Artistic representation of black phosphorus flake illuminated by a green laser. Red light: scattered light with energy different from the incident (Raman scattering). When rotating the crystal, the angular dependency measurements should behave according to the gray line shown at the end of the red light, but behave like the green dots.
Artistic representation of black phosphorus flake illuminated by a green laser. Red light: scattered light with energy different from the incident (Raman scattering). When rotating the crystal, the angular dependency measurements should behave according to the gray line shown at the end of the red light, but behave like the green dots.


B-MRS Newsletter: Cite the main results generated from the award-winning thesis.

Henrique Bücker Ribeiro: The work mentioned above generated an article (https://pubs.acs.org/doi/full/10.1021/acsnano.5b00698) that currently has more than 130 citations and is in the 1% of most cited articles in the area according to Essential Science Indicators, produced by Clarivate Analytics of the Thomson Reuters group.

The thesis is related to the following articles:

  • RIBEIRO, HENRIQUE B.; PIMENTA, MARCOS A. ; DE MATOS, CHRISTIANO J. S. ; MOREIRA, ROBERTO LUIZ ; RODIN, ALEKSANDR S ; ZAPATA, JUAN D. ; DE SOUZA, EUNEZIO A. T. ; CASTRO NETO, ANTONIO H. . Unusual Angular Dependence of the Raman Response in Black Phosphorus. ACS Nano, v. 9, p. 4270–4276, 2015.
  • RIBEIRO, H. B.; VILLEGAS, C. E. P. ; BAHAMON, D. A. ; MURACA, D. ; CASTRO NETO, A. H. ; de SOUZA, E. A. T. ; ROCHA, A. R. ; PIMENTA, M. A. ; de MATOS, C. J. S. . Edge phonons in black phosphorus. Nature Communications, v. 7, p. 12191, 2016.
  • RIBEIRO, HENRIQUE B.; PIMENTA, MARCOS A. ; DE MATOS, CHRISTIANO J.S. . Raman spectroscopy in black phosphorus. JOURNAL OF RAMAN SPECTROSCOPY, v. 49, p. 76-90, 2018.
  • RIBEIRO, H.B.; SATO, K. ; ELIEL, G.S.N. ; DE SOUZA, E.A.T. ; LU, CHUN-CHIEH ; CHIU, PO-WEN ; SAITO, R. ; PIMENTA, M.A. . Origin of van Hove singularities in twisted bilayer graphene. Carbon (New York), v. 90, p. 138-145, 2015.

In addition to articles from collaborations:

  • ELIEL, G. S. N. ; MOUTINHO, M. V. O. ; GADELHA, A. C. ; RIGHI, A. ; CAMPOS, L. C. ; RIBEIRO, H. B. ; CHIU, PO-WEN ; WATANABE, K. ; TANIGUCHI, T. ; PUECH, P. ; PAILLET, M. ; MICHEL, T. ; VENEZUELA, P. ; PIMENTA, M. A. . Intralayer and interlayer electron-phonon interactions in twisted graphene heterostructures. Nature Communications, v. 9, p. 1221, 2018.
  • ELIEL, G. S. N. ; RIBEIRO, H. B. ; SATO, K. ; SAITO, R. ; LU, CHUN-CHIEH ; CHIU, PO-WEN ; Fantini, C. ; RIGHI, A. ; PIMENTA, M. A. . Raman Excitation Profile of the G-band Enhancement in Twisted Bilayer Graphene. BRAZILIAN JOURNAL OF PHYSICS, v. 47, p. 589-593, 2017.
  • COSTA, M C FERRAZ DA ; RIBEIRO, H B ; KESSLER, F ; SOUZA, E A T DE ; FECHINE, G J M . Micromechanical exfoliation of two-dimensional materials by a polymeric stamp. Materials Research Express, v. 3, p. 025303, 2016.
  • FARIA, PAULA C. ; SANTOS, LUARA I. ; COELHO, JOAO PAULO ; RIBEIRO, HENRIQUE BUCKER ; PIMENTA, MARCOS A. ; LADEIRA, LUIZ O. ; GOMES, DAWIDSON A. ; FURTADO, CLASCIDIA A ; GAZZINELLI, RICARDO . Oxidized multiwalled carbon nanotubes as antigen delivery system to promote superior CD8+ T cell response and protection against cancer. Nano Letters (Print), v. 14, p. 5458-70, 2014.

During my PhD I was awarded the Nanocell Institute of Scientists of the Year Award in the category ‘Nanotechnology: from production to application’.

B-MRS Newsletter:  From your point of view, what are the main factors that led to an outstanding research work at the national level (your thesis)?

Henrique Bücker Ribeiro: Open dialogue with my mentors, collaborations, development agencies, the post-graduation program and the university, discussions with colleagues, support from my parents, support from technicians, a good work environment, dedication and effort and many other factors. Good work can be achieved when all these elements are in place. The absence of just one is enough to jeopardize the work.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

Henrique Bücker Ribeiro: Do not expect good results to materialize immediately and do not be discouraged when this is the case. Most of the time things will go wrong and even then, nothing will be wasted. A good result can be achieved by overcoming these difficulties and thinking about the problem.

Interview with Adriano dos Santos, winner of the award for the best thesis in the area of Chemistry.

  • Thesis: Development of an impedimetric/capacitive biosensor for the detection of biomarkers of clinical importance. Available at: https://repositorio.unesp.br/handle/11449/150274
  • Author: Adriano dos Santos.
  • Advisor: Paulo Roberto Bueno (Institute of Chemistry of Araraquara – UNESP).
  • Co-advisor: Maria del Pilar Taboada Sotomayor (Institute of Chemistry of Araraquara – UNESP).
  • Institution: Institute of Chemistry of Araraquara, State University of São Paulo (UNESP).
Adriano dos Santos
Adriano dos Santos

For Adriano dos Santos (35, a native of Araraquara, São Paulo), the laboratory classes he had in the Chemistry undergraduate course at UNESP, in the Araraquara campus, were genuine foundations of his education. The tools and competences developed in these practical classes were very useful for Santos, both in the stages he performed in a company that produces paints and coatings, and in the stages of scientific initiation at UNESP, under the guidance of professors Antonio Eduardo Mauro and Paulo Roberto Bueno.

In 2010, Santos began his Master’s in Chemistry, also at UNESP under the guidance of Professor Bueno. During the master’s research, in which he developed a piezoelectric device to understand a biological process, Santos began to learn about biosensors-related topics and to develop a special interest in this research area. After defending the dissertation, and while working in a chemical company, Santos decided to do a doctorate in a subject related to biosensors. In 2013, he began the doctorate activities. Again under the guidance of Professor Bueno and co-advised by Professor Maria del Pilar Taboada Sotomayor, he developed his research project at the Institute of Chemistry of Araraquara, UNESP. From September 2016 to February 2017, Santos was at the University of Oxford (England) performing part of the research under the guidance of Professor Jason Davis. “This enabled me to expand my knowledge and critical analysis with invaluable gains in professional experience and qualification,” says Santos.

In his thesis, Santos presented a new application of existing techniques that generated biosensors with possible applications in the detection of thrombosis and cancer and in the study of biological phenomena. Currently, the prize winner continues working in this area with Professor Bueno, as a postdoctoral fellow.

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

Adriano dos Santos: Biosensors are currently receiving considerable attention due to their economic (investment and market) and social (health impact and population quality of life) potential. These devices, in which the glucometer (device that measures the glucose content directly from the blood) is its greatest example, have the capacity to perform clinical diagnosis faster than the current methods, as well as limits of detection (smaller amount that can be detected in a sample) that is suitable for early diagnosis. Early detection is highly relevant when, for example, performing cancer diagnosis is desired. This is because the chances of cure and the survival time of patients with this disease are greatest when detected in the early stages.

In my thesis it was demonstrated that by means of an electrochemical transduction of a biological recognition signal, called electrochemical capacitance, and also through new data analysis known as immitance functions, there is the potential to diagnose certain diseases in a sensitive and early manner, including cancer and thrombosis, without the need to use enzymatic or fluorescent labels used in the current clinical analysis. In addition, the use of this innovative electrochemical approach in the development of interfaces with potential applications in glycobiology is also unprecedented. The importance of this approach is to provide a new tool that will help researchers understand processes that are related to the interaction of proteins and carbohydrates. In this context, it is possible to encompass cellular invasion processes (whose knowledge may assist in the development of vaccines), and the understanding of the mechanism of tumor formation and proliferation. It is possible that this new approach may one day be employed in developing a technological platform for the development of glycoarrays (that is, techniques that allow the study of interactions between proteins and carbohydrates).

(a)Example of an interface for the detection of biomarkers (molecules related to a certain disease). The interface consists of a monolayer composed of electroactive species and the recognition element (such as, for example, antibody). The interaction between the recognition element and the biomarker causes a change in the electrochemical capacitance signal (b), allowing to construct calibration or saturation curves (c).
(a)Example of an interface for the detection of biomarkers (molecules related to a certain disease). The interface consists of a monolayer composed of electroactive species and the recognition element (such as, for example, antibody). The interaction between the recognition element and the biomarker causes a change in the electrochemical capacitance signal (b), allowing to construct calibration or saturation curves (c).

B-MRS Newsletter: Cite the main results generated from the award-winning thesis.

Adriano dos Santos: Specifically from the thesis, there were five published works:

In addition, during the period of my PhD research, there were six more articles published, in partnership, on topics related to the thesis.

It is also important to emphasize that during this period, a clinical diagnosis company was created, with my thesis supervisor, Prof. Dr. Paulo Roberto Bueno, and Prof. Dr. Jason Davis of the University of Oxford, as the founders. This company, Osler Diagnostics, is a spinout located in the city of Oxford, England, which is using part of the research generated in this thesis for its technological development.

B-MRS Newsletter: From your point of view, what are the main factors that led to this outstanding research work at the national level (your thesis)?

Adriano dos Santos: There are many factors, such as the infrastructure of the institution that contains equipment and professionals capable of performing tests and measurements that underlie the theory, as well as research support from the library to the post-graduate technical section, including the entire staff; the excellence of the group of researchers from UNESP – Institute of Chemistry, which includes my advisor (Prof. Dr. Paulo Roberto Bueno) and co-adviser (Prof. Maria Del Pilar Taboada Sotomayor) of the thesis, who assisted me with much advice and learning; the possibility of attending international scientific events, in which the importance of mastering English as a second language was crucial to promote the exchange of knowledge with the researchers in the events; the partnership between UNESP and Oxford University through a MoU (Memorandum of Understanding), which encourages researchers to carry out academic cooperation, raising the level of scientific discussion, and from which favored my internship abroad at this university, under the guidance of Prof. Dr. Jason Davis; and the funding of federal (CAPES and CNPq) and state (FAPESP) agencies through thematic projects and a doctoral grant.

I would like to take this opportunity to thank the Institute of Chemistry-Campus of Araraquara (technicians, professors and researchers) involved in my thesis, to the University of Oxford, especially to Prof. Dr. Jason Davis, for having welcomed me to his laboratory, family and friends, as well as CAPES, CNPq and FAPESP for the financial support.

B-MRS Newsletter:  Leave a message to our readers who are undergraduate or graduate students.

Adriano dos Santos: Science is beautiful, and like a sculpture it requires the effort to polish the stone so the art is revealed. The journey to the goal is like a course, often tortuous, that deceives us and forces us to redirect our trajectories. Science is not linear, in that knowledge is ready and finished, but rather a constant review and advance of what is being done, especially for applications in new technologies, which require “returns” and new interpretations of knowledge previously seen as untouchable. Thus, it can be characteristic for the undergraduate student (when in a scientific initiation), and especially for the postgraduate, to encounter unexpected or difficult to interpret results, which may often be grounds for discouragement and abandonment of his/her research project. The only way to overcome these problems is through ethical conduct and professionalism, knowing how to recognize one’s limitations and seek continuous help from his or her supervisor or other researchers in the area. And also always be open-minded and question oneself, not with skepticism, but with consideration to understand the system that is the study object.

Not less important is to remember that it is necessary for family to be close and for friendships to be cultivated. Setting aside leisure time such as hobbies and reading, different from those we are usually accustomed to in academia, are crucial. Consider practicing a physical activity and studying a second language, especially English, as there will certainly be opportunities in which that language will be crucial for career advancement, whether as a university professor or as a professional in a company.


Featured paper: Towards two-dimensional diamond.

Two-dimensional materials, those whose thickness goes from an atom to a few nanometers, have unique properties related to their dimensionality and are protagonists in the development of nanotechnology and nanoengineering.

A team of scientists from five Brazilian institutions and one American institution took an important step in the development of the two-dimensional diamond version. This work on 2D diamond was reported in a paper published in Nature Communications (impact factor 12,124) with open access.

“Our work presented spectroscopic evidence of the formation of a two-dimensional diamond, which we named diamondene”, says Luiz Gustavo de Oliveira Lopes Cançado, professor at the Brazilian Federal University of Minas Gerais (UFMG) and corresponding author of the paper. In choosing the name of the new material, the scientists followed the tradition of using the suffix “ene” for two-dimensional materials, as with graphene, 2D version of the graphite.

box_enIn fact, it was from the compression of graphene sheets that the diamondene was obtained by the team led by Professor Cançado. Initially, the team deposited two layers of graphene one on top of the other and transferred the graphene bilayer to a Teflon substrate, chosen for being chemically inert, preventing the formation of bonds with the graphene.

The sample of bi-layered graphene on Teflon was then subjected to high pressures and simultaneously analyzed by Raman spectroscopy at the Laboratory of Vibrational Spectroscopy and High Pressure of the Department of Physics of the Brazilian Federal University of Ceará (UFC). The experimental system used was a diamond anvil cell with a coupled Raman spectrometer. This equipment allows high pressure to be applied to small samples that are immersed in a pressure transmitting medium (in this case, water). The pressure is applied through two pieces of diamond (material chosen for being one of the hardest and resistant to compression), which compress the transmitting medium, which passes the pressure to the sample. At the same time, the spectrometer allows to monitor the changes that occur in the structure of the sample material against the different pressures applied. “In Raman spectroscopy, light behaves like a probe that measures vibrational states of the material,” explains Cançado. As a result of the probing, the spectrometer generates graphs (spectra), through which it is possible to identify the structure of the material being studied.

By analyzing the spectra, the team of scientists observed changes in the two-dimensional material that indicated the transition from a graphene structure to a diamond structure. The researchers were able to conclude that the diamondene was obtained at a pressure of 7 gigapascals (GPa), tens of thousands of times higher than the atmospheric pressure. “The evidence we present in this work is a signature in the vibrational spectrum obtained from a two-dimensional carbon material that indicates the presence of sp3 bonds, typical of the structure of the diamond,” says Professor Cançado.

To explain the formation of diamondene, the team used first principles calculations following the Density Functional Theory and Molecular Dynamics simulations. “These theoretical results guided the experiments and allowed us understanding the experimental results,” says Cançado.

Scheme of the diamondene formation mechanism from two layers of graphene submitted to high pressures (blue arrows) in water as pressure transmitting medium. The gray colored balls represent the carbon atoms; the red ones, the oxygen atoms, and the blue ones, the hydrogen atoms.
Scheme of the diamondene formation mechanism from two layers of graphene submitted to high pressures (blue arrows) in water as pressure transmitting medium. The gray colored balls represent the carbon atoms; the red ones, the oxygen atoms, and the blue ones, the hydrogen atoms.

According to the theoretical results, when the bilayer graphene system on inert substrate with water as pressure transmitting medium is subjected to high pressures, the distances between the elements of the system decrease and new connections occur among them. “When applying this level of pressure on graphene, connections can change, going from the sp2 configuration to the sp3 configuration,” explains Professor Cançado. The carbon atoms in the upper graphene layer then establish covalent bonds with four neighboring atoms: the atoms of the lower layer and the chemical groups offered by water (OH- and H). The latter are fundamental to stabilize the structure. In the lower layer, in contact with the inert substrate, half of the carbon atoms are bound to only three neighboring atoms. “The pending connections give rise to a gap opening in the electronic structure, as well as polarized spin bands,” adds Cançado.

This feature makes diamondene a promising material for the development of spintronics (the emerging strain of electronics at the nanoscale in spin-bases electronics). According to Cançado, diamondene could also be used in quantum computing, microelectromechanical systems (MEMS), superconductivity, electrodes for electrochemistry-related technologies, DNA engineering substrates and biosensors – applications in which thin diamond films have already proven to have good performance.

However, there is still a long way to go before demonstrating the diamondene applications. Firstly, because the diamondene shown in the article dismantles under normal pressure conditions. To overcome this limitation, the group of Professor Cançado at UFMG is setting up an experimental system that will allow the application of much higher pressures to the samples in the order of 50 GPa and analyze them using Raman spectroscopy. “With this we intend to produce stable diamondene samples, which remain in this form even after having the pressure reduced to the level of ambient pressure,” says Cançado.

In addition, since Raman spectroscopy provides indirect evidence of the structure of the material, it will be necessary to perform direct measurements of the diamondene to know its structure in detail. “The most promising techniques in this case would be X-ray diffraction in synchrotron light sources or electron diffraction,” suggests Cançado. “The complicating factor in this experiment is the need to have the sample subjected to high pressures,” he adds.

The Brazilian history of diamondene

The idea of the 2D diamond formation originated in the doctoral research of Ana Paula Barboza, conducted under the guidance of Professor Bernardo Ruegger Almeida Neves and defended in 2012 in the Department of Physics of UFMG. In this work, Cançado says, atomic force microscopy (AFM) tips were used to apply high pressures on one, two and several layers of graphene. Indirect evidence of the formation of a two-dimensional diamond was obtained by means of electric force microscopy (EFM). The work showed the importance of the presence of two layers of graphene and water for the formation of the sp3 two-dimensional structure. The main results of the research were reported in the article Room-temperature compression induced diamondization of a few-layer graphene [Advanced Materials 23, 3014-3017 (2011)].

Main article authors. On the left, Luiz Gustavo Pimenta Martins (MSc from UFMG and doctoral student at MIT). On the right, Professor Luiz Gustavo Cançado (UFMG).
Main article authors. On the left, Luiz Gustavo Pimenta Martins (MSc from UFMG and doctoral student at MIT). On the right, Professor Luiz Gustavo Cançado (UFMG).

“The idea of measuring the Raman spectrum of graphene under high pressure conditions (using anvil diamond cells) came after Luiz Gustavo Pimenta Martins, an undergraduate student at the time, developed a very efficient method of transferring graphene to different substrates,” says Professor Cançado. This development was carried out during a visit to the laboratory of Professor Jing Kong at the Massachusetts Institute of Technology (MIT), after having won a grant for international mobility of the Formula Santander Award. During his master’s degree at the Physics Department of UFMG, carried out under the guidance of Professor Cançado and defended in 2015, Pimenta Martins carried out an extensive and systematic work to obtain Raman spectra of graphene samples subjected to high pressures. “There were many visits to UFC and much study until understanding the diamondene formation mechanisms,” explains Cançado.

The research reported in the Nature Communications paper was made possible by the collaborative work of several Brazilian research groups with recognized expertise in various subjects, as well as the participation of the MIT researcher in the sample preparations. Scientists from the physics departments of UFMG and UFC have contributed their recognized expertise in Raman spectroscopy applied to carbon nanomaterials and, in the case of UFC, in experiments under high pressure. Also participating in these experiments were researchers from the Brazilian Federal Institute of Education, Science and Technology of Ceará and the Brazilian Federal University of Piauí (UFPI). In addition, theoretical physicists from the Brazilian Federal University of Ouro Preto (UFOP) and UFMG performed calculations and computational simulations.

The research was funded by Brazilian federal agency CNPq, state agencies FAPEMIG and FUNCAP, Formula Santander Program and UFOP.

[Paper: Raman evidence for pressure-induced formation of diamondene. Luiz Gustavo Pimenta Martins, Matheus J. S. Matos, Alexandre R. Paschoal, Paulo T. C. Freire, Nadia F. Andrade, Acrísio L. Aguiar, Jing Kong, Bernardo R. A. Neves, Alan B. de Oliveira, Mário S.C. Mazzoni, Antonio G. Souza Filho, Luiz Gustavo Cançado. Nature Communications 8, Article number: 96 (2017). DOI:10.1038/s41467-017-00149-8. Disponível em: https://www.nature.com/articles/s41467-017-00149-8]

New journal: npj 2D Materials and Applications.

Aiming to create a top-tier interdisciplinary platform for scientists to share and promote 2D materials research and applications, npj 2D Materials and Applications is a new online-only, open access journal.

2D Materials and Applications is part of the Nature Partner Journals (npj) series, launched by Springer Nature as part of the Nature Research portfolio of journals, and published in partnership with the Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (FCT Nova) with the support of the European Materials Research Society (E-MRS).

npj 2D Materials and Applications will publish original papers, review articles and short communications to reflect the latest breakthrough and developments taking place in all aspects of 2D materials, including allotropes (different structures of the same element) and compounds, ultralight composite materials, their properties (including mechanical properties), and their isolation, synthesis and manufacturing.

The journal will also publish research relating to the use of 2D materials in applications such as photovoltaics, optoelectronics and photonics, semiconductors, sensors, electrodes, water purification/filtration/distillation, and energy storage.

Led by Editor-in-Chief Professor Andras Kis, the journal is now open for submissions.

Visit the journal website to find out more: http://www.nature.com/npj2dmaterials/

See flyer here.

Featured paper. Nanometric Origami: organized strain of two-dimensional materials

Paper: Crystal-oriented wrinkles with origami-type junctions in few-layer hexagonal boron nitride. Oliveira, Camilla K.; Gomes, Egleidson F. A.; Prado, Mariana C.; Alencar, Thonimar V.; Nascimento, Regiane; Malard, Leandro M.; Batista, Ronaldo J. C.; de Oliveira, Alan B.; Chacham, Helio; de Paula, Ana M.; Neves, Bernardo R. A. Nano Research. 2015, 8(5): 1680–1688. DOI: 10.1007/s12274-014-0665-y.

Camilla Oliveira at the atomic force microscope.

Camilla Oliveira was at the Federal University of Minas Gerais (UFMG), in Brazil, studying samples of hexagonal boron nitrite (hBN) with an atomic force microscope (AFM) within the framework of her doctoral studies in Physics, when one particular aspect of the control samples caught her attention and that of her advisor, Professor Bernardo Neves. After undergoing a heat treatment (annealing), the hBN had gained nanometric wrinkles, arranged in a geometric pattern that seemed to follow some sort of organization.

The researchers decided to study these wrinkles in more detail. They had an important question to answer: was there any relation between the arrangement of the wrinkles and the hBN crystal structure? In other words, did these wrinkles have a crystallographic orientation?  Until that moment, there were no records in scientific literature of crystallographically-oriented wrinkles in two-dimensional materials, but this property could be useful.

The two-dimensional hBN crystal lattice (1 atom high).

Camilla and her advisor joined other scientists from UFMG and the neighbor Federal University of Ouro Preto (UFOP) in order to carry out that research. The team produced samples composed of a few layers of hBN anchored on a silicon substrate, they heated them at 1,000 degrees Celsius and then cooled them. During this process, the silicon and the boron nitride displayed opposite strain behaviors. Due to the heating, the hBN contracts itself, while the silicon expands, shrinking the hBN. On the other hand, the cooling expands the hBN and shrinks the silicon, folding the boron nitride as origami paper.

After much experimental work using several techniques and approaches, and various simulations, the scientists were able to confirm that the wrinkles were forming in well-defined directions inside the crystal lattice. Analyzing the folding pattern in details, the scientists noticed the triangular-shaped joints by which the wrinkles (usually three of them) met.

AFM images of a 10nm thick hBN flake after the heat treatment, displaying a crystallographically-oriented pattern of wrinkles (left); details of a typical joint (right). The average height of the wrinkles is 10nm.

Detail: as proven by the Brazilian scientists, for the crystallographically-oriented folding patterns to be formed, the heat treatment must consist of rapid heating, followed by slow cooling (for example, citing the rates used in the research, 50 °C per minute to heat, and 8 °C per minute to cool). The wrinkles produced with faster cooling rates are arranged in a disorderly manner, with no crystallographic orientation.

The researchers have also concluded that this type of organized strain could happen, not only to hBN, but to other two-dimensional materials as well, such as graphene, and that it could lead to interesting applications in straintronics – the field of knowledge that studies and explores the capacity of some materials to have their properties deeply changed due to strain processes.

The results of the research were recently published on the scientific journal Nano Research.

“In my opinion, the main contribution of the paper is to present a property that may be shared by many two-dimensional materials: the organized strain, i.e., strain in well-defined crystallographic directions, of a material at the nanoscale”, says Professor Neves, who is the corresponding author of the paper.

The research was funded by the Brazilian agencies Capes, CNPq and Fapemig, and by INCT-Nanocarbono.

SBPMat’ s community people: interview with Helio Chacham.

During his childhood and adolescence in Belo Horizonte, in the 1960s and 1970s, Helio Chacham had many incentives to become interested in science. After that, in higher education phase, Chacham first started Electrical Engineering but ended up choosing Physics. And that was the field he chose for his undergraduate, masters and doctoral degrees at the Federal University of Minas Gerais (UFMG).

Shortly after completing his doctorate program, he joined the UFMG as Associate Professor, and afterwards he left for the United States to engage in a nearly two-year postdoctoral stage at the University of California in Berkeley. Back in Minas Gerais, between 1995 and 1997, he coordinated the graduate program in Physics at UFMG. From 1999 to 2000, he returned to the United States to engage in a second postdoctoral stage at the University of Texas in Austin. In 2004, he became a Full Professor at UFMG.

Over 30 years of scientific activity, professor Chacham has studied various materials with theoretical research based on the intensive use of computations, although in many opportunities he has worked in collaboration with experimental research groups. Early in his career, Chacham made important contributions to the study of properties of materials under ultra-high pressure. Since the mid-1990s, the researcher has dedicated himself, together with his group and collaborators, to predicting, verifying and explaining phenomena occurring in nanomaterials and two-dimensional materials, also making significant contributions on the same subject.

Currently aged 55, Helio Chacham is a level 1A productivity fellow (the highest level) at the Brazilian National Research Foundation – CNPq. He is the author of around 100 papers published in international peer review journals, which have over 1,800 citations. Chacham is the sub-coordinator of the National Institute of Science and Technology (INCT) of Carbon Nanomaterials. In December 2014, he was elected member of the Brazilian Science Academy (ABC).

Below is an interview with the scientist.

SBPMat newsletter: – How did you become interested in science? What led you to become a scientist and to work in Condensed Matter Physics?

Helio Chacham – My childhood was during the 60s and 70s, a time when there was great interest in science and technology – in part due to the space race and the man going to the moon. As a child and teenager, I always had access to science books (I remember “The Universe” by Isaac Asimov) and also science fiction books (also several by Asimov). At this time I also collected science experiment kits that were sold at newsstands – they were great kits with materials and instructions for experiments, also including small texts on scientists associated with the experiments. The schools I attended as from the 5th grade (both linked to the Federal University of Minas Gerais, UFMG) had good laboratories and good science teachers, which also encouraged me in that direction.

Upon my entry at the University (UFMG), I started as an Electrical Engineering student, but after the first year, I found that my biggest interest was in the fields of Physics and Computer Science. So I switched to the Physics course and meanwhile, for some time, I performed research in Computer Science. Then I was accepted in master´s courses in both – Physics and Computer Science – and ended up choosing the former. Since then, I have devoted myself to research in Condensed Matter Physics, perhaps because it is somehow related to my previous interests (Engineering and Computer Science).

SBPMat newsletter: – In your own assessment, what are your main contributions to the field of Materials?

Helio Chacham – In the 90s I devoted myself primarily to theoretical investigation of properties of materials under ultra-high pressure. These properties are relevant, on the one hand, under the academic point of view, because they allow investigating conditions similar to those of planetary interiors. In addition, these properties determine the limits of hardness of materials, such as the diamond. My largest contributions in this field were the determination of the pressure above which hydrogen becomes a metal – which occurs within Jupiter – and the theoretical determination of one of the diamond hardness measurements, the optimum shear strength.

Since the mid-90s, I started a research line on nanomaterials. This has been one of the most active areas of research in materials since the discovery of fullerenes and carbon nanotubes. My first contributions in the area, in collaboration with students, were predicting morphologies of boron nitride fullerenes and predicting the transformation of electronic properties of carbon nanotube – from insulating into metallic – when subjected to compression. The latter phenomenon was only experimentally demonstrated several years later, in a collaborative work with experimental researchers in my own department – the UFMG Physics Department. These theoretical/experimental collaborations have had a fruitful continuing so far, which has allowed us to predict, verify and explain various new phenomena in carbon nanotubes, graphene and two-dimensional materials, phenomena such as: the negative dynamics compressibility in graphene; wrinkle crystallization in boron nitride; and talc exfoliation up to the single layer boundary, similar to that of the graphene, and determination of properties of this new two-dimensional material.

During all of these projects I was always concerned in training masters´ and doctors, whose theses dealt with electronic and structural properties of nanotubes, fullerenes, DNA, nanoparticles, nanowires, graphene and other two-dimensional materials. These former students are now professors and researchers at UFMG and other universities, and have carried out several projects, mainly in the nanomaterials field.

SBPMat newsletter: – Last year you were elected member of the Brazilian Science Academy (ABC). What that means to you? How do you see your role within the ABC?

Helio Chacham – I deeply appreciate the support of my colleagues of the Academy in the election. I will take office in May, and then, will be able to seek ways to contribute with ABC, whether by participating in committees or in specific projects of the Academy, or by collaborating with Science Academies in other countries, one of which I have already participated (Brazil/India) before joining as a member. As I have been providing service to the community, whether, for example, as a member of the advisory committee of the CNPq or by coordinating projects in nanomaterials, I believe that my election will allow me to continue to contribute with the research community in many ways.

SBPMat newsletter: – Leave a message for our readers who are starting their careers as scientists.

Helio Chacham: – Based on my professional experience so far, I may be able to give some advice – which can be useful or not depending on the personality of each person, of course:

a) Work on what you really enjoy – the researcher’s career is one of the few that allow you to do so.

b) Search research areas with many issues to be solved, or new materials being produced, and which are consistent with item (a) above. For that matter, it is important to always keep up with scientific literature.

c) Master the methods you use as deeply as possible. That will allow you to attack difficult and important issues.

d) Always be willing to study and learn new methods. That will give you the flexibility and the ability to search for new issues and research areas, as well as to collaborate with researchers using other methodologies. Science changes continuously and constantly.