The proceedings of the 6th International Conference on Electroceramics, held at João Pessoa on November 2013, under the auspices of SBPMat, were published online on Trans Tech Publications Inc.’s “Advanced Materials Research” (AMR) journal, volume 975.
The Publishing Committee, composed of Drs. Daniel Zanetti de Florio, Fábio Coral Fonseca, Eliana N.S. Muccillo and Reginaldo Muccillo, was responsible for the editing of this volume of AMR, after comprehensive peer review.
Each corresponding author has their login to access their articles online.
Brazilian Materials Research Society (SBPMat) newsletter
News update from Brazil for the Materials community
English edition. Year 1, issue 9.
Greetings, .
Final arrangements for our meeting in João Pessoa!
– Read the message of the chairs of the event, which this year accepted 2,141 papers and has nearly 2,000 registrations from 28 countries so far. In the message, professors Ieda Garcia and Severino de Lima show the highlights of the program of this year’s meeting! Here.
– After lunch and before the afternoon plenary lectures, you can attend technical lectures of the meeting´s sponsors in João Pessoa: Shimadzu/Tescan will discourse about SEM with ion beam and TOF SIMS detector, and FEI will address DualBeam TEM. Learn more.
– Why is João Pessoa called “the sun door“? Learn more about the city, one of the oldest in Brazil, and its natural and cultural features. And get ready to dive into green waters at 28 °C! Read about João Pessoa.
– What to pack? Track the weather, whose temperatures should be between 20 °C and 30 °C. But pay attention, the meeting organization warns that, at the Convention Center, the air conditioner will make the room fresh … Link to weather in João Pessoa.
– Detailed schedule. Search for times and locations of symposia presentations: here.
– Some options of accommodation, car rental, transfers from the airports of the region, transportation from hotels to convention center, and tours: see on the home page of the site of the event.
– And what about the conference party? This year, it will be held on Wednesday evening at Espaço Caixa Econômica Federal in Cabo Branco. Tickets may be purchased in the information desk as of Monday 1 p.m..
Interviews with our plenary speakers
We interviewed Robert Chang, professor of the first department of Materials Science in the world at Northwestern University. Besides having a remarkable career as a researcher (his H index is 56), “Bob” has dedicated the past 20 years guiding the development of the Materials World Modules program, which develops educational, interactive and playful material (for example, card games) on Materials and Nanotechnology for pre-college students and their teachers. In his plenary lecture at the XIII SBPMat Meeting, Professor Chang will try to mobilize citizens of the world to solve global problems together. See our interview with the scientist.
We also spoke with Professor Colin Humphreys, a professor at the University of Cambridge. Among other honors, the scientist was knighted by the Queen of England for his services to science. Besides being the author of over 600 publications, the professor developed materials for the industry that currently fly in aircraft engines and created low cost LEDs based on gallium nitride, material on which he specialized. In João Pessoa, he will show, among other issues, how gallium nitride could reduce electricity consumption by 25% in the world. See our interview with Colin Humphreys.
We interviewed the German physicist Karl Leo, specialist in organic semiconductors. Beyond being the author of more than 550 papers with more than 23,000 citations and 50 families of patents, the scientist has already participated of the creation of 8 spin-off companies. In his lecture at the XIII SBPMat Meeting, Karl Leo will speak on highly efficient organic devices, as OLEDs and solar cells. See our interview with Karl Leo.
We also spoke with the Portuguese physicist Antonio Luis Ferreira Martins Dias Carlos, of the University of Aveiro, who will perform a lecture in our meeting in João Pessoa on luminescence applied to nanomedicine. In the interview, the professor shared with us his most prominent works in the field of Materials. He also told us about some challenges in the area of luminescence for medical applications, both in medical imaging and intra-cellular temperature mapping, and cited examples of applications of luminescent materials that have already been used in the diagnosis and treatment of various diseases. See our interview with Luis Dias Carlos.
We interviewed the French scientist Jean-Marie Dubois (Institut Jean-Lamour), specialist in quasicrystals (ordered, but aperiodic structures on solid materials) and pioneer in patenting applications for them. He told us a little about his main contributions to the field of Materials and gave a teaser on the theme of his plenary lecture in the XIII SBPMat Meeting: he will talk about quasicrystal structures, found in metallic alloys, polymers, oxides and artificial nanostructures, and their unprecedented properties. In the picture, Jean-Marie Dubois (on the left) and Dan Shechtman, who received a Nobel Prize in 2011 for the quasicrystals, using equal ties, both decorated with the Penrose tiling, an example of aperiodicity. Read our interview with Jean-Marie Dubois here.
We also interviewed the Italian chemist Roberto Dovesi (Universita’ degli Studi di Torino), one of the creators of CRYSTAL, a computational tool for ab initio quantum calculations used in the study of several solid materials properties. The CRYSTAL code is currently used in over 350 laboratories around the world. In his plenary lecture in the XIII SBPMat Meeting, Dovesi will attempt to demonstrate that today quantum simulations may be very useful tools to complement experiments. See our interview with Roberto Dovesi.
We have interviewed Professor Alberto Salleo, from Stanford University, who is going to give a plenary lecture on organic electronic devices in the XIII SBPMat Meeting. Young, yet holding a career that stands out internationally, Salleo told us about the work conducted by his group, which has been developing a deeper understanding on the role provided by the defects in charge transport in organic semiconductors. He also shared with us his main papers, published in Nature Materials. Finally, Salleo discussed the next challenges and applications on organic electronics, and anticipated what he is going to address in the plenary lecture, which promises to be very informative while mild enough for a wider audience. Read our interview with Alberto Salleo.
To suggest news, opportunities, events or reading recommendations items for inclusion in our newsletter, write to comunicacao@sbpmat.org.br.
Behind, João Pessoa city. Ahead, coral reefs at Picãozinho, 1,500 meters far from Tambaú beach. Foto: Cacio Murilo.
João Pessoa is the third Brazilian oldest city, being the capital of the state of Paraiba located in the Northeast of the country. It has a population about 770,000, while its metropolitan area comprises 8 satellite cities with 1,223,000 inhabitants. With a hot humid climate, João Pessoa has an average annual temperature around 26o C, reaching 29o C between September and October.
João Pessoa is known as the “Sun Door” or as “the city where the sun rises first”, having the easternmost point of Brazil. It has also a very beautiful sunset which can be admired at the sound of Ravel´s Bolero, in the “Praia do Jacaré”. It is also one of the greenest cities of the world, due to the presence of two reserves of Atlantic Forest inside the city.
João Pessoa has an important local culture. The architectonic-historic collection is very rich with baroque buildings from the XVI century, which worth a visit.
“Cabo Branco” Science, Culture and Art Station. Foto: Cacio Murilo.
Another touristic point is the “Cabo Branco” Science, Culture and Art Station, located at the easternmost point of the Americas (Ponta do Seixas), which is both an educational and cultural institution as well as a national landmark. The complex, inaugurated in 2008, was created by Brazilian architect Oscar Niemeyer and is one of his latest projects.
But the main touristic attractions of João Pessoa are its 18 beautiful beaches of green warm water – with a water average temperature of 28oC. Seven of these beaches are located in urban areas, with easy acces, very inviting for a nice swim.
We hope to see you at the XIII Brazilian Materials Research Society Meeting, held on 28 September to 02 October, 2014, in João Pessoa, PB, Brazil. This year the meeting has 2,141 accepted abstracts and, up to this moment, almost 2,000 inscriptions from Brazil and other 27 countries.
The XIII Meeting is comprised of 19 Symposia following the format used in tradicional meetings of Materials Research Societies, involving topics as synthesis of new materials, computer simulations, optical, magnetic and electronic properties, traditional materials as clays and cements, advanced metals, carbon and graphene nanostructures, nanomaterials for nanostructures, energy storage systems, composites, surface engineering and others. A novelty is a symposium dedicated to the innovation and technology transfer in materials research. The program also includes 7 Plenary Lectures presented by internationally renowned researchers.
This year, the B-MRS will present the results of two important actions from our society. The first one is the meeting of the B-MRS directory with the University Chapters (UC) already established and the students who want to establish other UC´s. The second one is the launch of the IOP publication on behalf of the B-MRS, Materials Science Impact, reporting advances in Materials Research in Brazil.
The Opening Ceremony will be followed by the Memorial Lecture “Joaquim Costa Ribeiro”, Progresses in Materials Research in Brazil by Professor José Arana Varela. During the Closing Ceremony the symposium coordinators will honor students with the “Bernhard Gross Award” for the best poster and the best oral presentation of each Symposium.
On behalf of Organizing Committee, we would like to thank the Brazilian Materials Research Society staff and board, the hired agencies, the symposium coordinators, the program, local and national committee members, for their commitment and great effort to make this Meeting possible.
We hope that the participants will have a very pleasant Meeting with stimulating exchange of scientific informations and establishment of new collaborations.
Ieda M. Garcia dos Santos and Severino Jackson Guedes de Lima
Prof. Chang and other developers of Nanocos, a card game that encourages students to learn science concepts and their role at the nanoscale.
Robert Chang is a Professor of Materials Science and Engineering at the first materials science academic department in the world, created more than 50 years ago at Northwestern University, where he is also director of the Materials Research Institute.
He holds a Bachelor of Science in Physics from Massachusetts Institute of Technology (MIT) and a Ph.D in Plasma Physics from Princeton University. He spent 15 years performing basic research at Bell Labs (Murray Hill). During the past 28 years at Northwestern University, he has directed several National Science Foundation (NSF) centers and programs in materials research and education.
Prof. Chang was the president of the Materials Research Society (MRS) in 1989. He is the General Secretary and Founding President of the International Union of Materials Research Societies (IUMRS). He has received many distinctions for his work, such as the Woody Award from MRS in 1987, the Siu Lien Ling Wong Fellow from the Chinese University of Hong Kong in 1999, and the NSF Director’s Distinguished Teaching Scholar Award in 2005. He is fellow of the American Vacuum Society and MRS, and honorary member of Materials Research Societies of India, Japan and Korea.
He is (co)author of 400 peer reviewed journal articles, with near 13,000 citations, and h-index of 56.
Read our interview with the plenary speaker.
SBPMat newsletter: – Under your viewpoint, which are your main contributions in the field of Materials Science and Engineering?
Robert Chang: 1. Plasma processing of semiconducting materials;
2. Carbon based materials, such as diamond, fullerene, and carbon nanotubes, and their related devices;
3. 3rd generation solar cells;
4. Infrared plasmonics and sensors;
5. Thin film oxides for electronic and photonic devices.
Top publications below.
H. Cao, Y. G. Zhao, S. T. Ho, E. W. Seelig, Q. H. Wang, and R. P. H. Chang. Random Laser Action in Semiconductor Powder. Phys. Rev. Lett. 82, 2278 (1999); DOI:http://dx.doi.org/10.1103/PhysRevLett.82.2278.
Michael D. Irwin, D. Bruce Buchholz, Alexander W. Hains, Robert P. H. Chang, and Tobin J. Marks.p-Type semiconducting nickel oxide as an efficiency-enhancing anode interfacial layer in polymer bulk-heterojunction solar cells. PNAS, vol. 105 no. 8, 2783–2787 (2008); doi: 10.1073/pnas.0711990105.
Q. H. Wang, A. A. Setlur, J. M. Lauerhaas, J. Y. Dai, E. W. Seelig and R. P. H. Chang. A nanotube-based field-emission flat panel display. Appl. Phys. Lett. 72, 2912 (1998);http://dx.doi.org/10.1063/1.121493.
Quanchang Li, Vageesh Kumar, Yan Li, Haitao Zhang, Tobin J. Marks, and Robert P. H. Chang. Fabrication of ZnO Nanorods and Nanotubes in Aqueous Solutions. Chem. Mater., 2005, 17 (5), pp 1001–1006. DOI: 10.1021/cm048144q.
SBPMat newsletter: – And what about your main contributions to science education, especially in Materials Science?
Robert Chang: – Over the past 20 years, I have led the development of the Materials World Modules program to teach pre-college students about Materials and Nanotechnology: materialsworldmodules.org; nclt.us; gsasprogram.org; imisee.net.
SBPMat newsletter: – Please give us a short teaser about your plenary talk at SBPMat meeting. What do you intend to broach?
Robert Chang: – Mobilizing world-citizens to solve global problems together!
SBPMat newsletter: – Feel free to leave other comments to our readers from the Materials research community, if you want so.
Robert Chang: – Materials and nanotechnology research and education are the driving force of all future technologies, including energy, environment, health, and security.
Faculties and students receiving lab equipment through a window in 2007.
This August records the 10th anniversary of one of the 31 Brazilian graduate programs in the field of Materials: the Graduate Program in Materials Engineering and Science of the University of Caxias do Sul (PGMAT – UCS in Portuguese).
PGMAT-UCS history dates back to the year of 2003, when Israel Baumvol, physicist and researcher in the area of Materials, was invited by authorities of UCS to lead the creation of a graduate program in this field of knowledge. Baumvol was, at the time, retiring from his position as professor at the Brazilian Federal University of Rio Grande do Sul (UFRGS).
In August, 2004, after conducting a selection process that had 85 applicants for 15 vacancies, PGMAT-UCS started the activities of its Master’s Degree course under the coordination of professor Baumvol. The program then had some laboratories that already existed at the university and a few professors with PhD, and offered the only graduate course at the university in the area of Sciences and Engineering.
Nowadays, the program has more than 20 laboratories and an all its professors hold PhDs. Since 2012, PGMAT also offers a doctoral program, which currently has 19 students.
The same room is today the Laboratory for Surface Characterization at the Nanoscale and has a GDOES analyser, among other instruments.
Another achievement of the program was the signing of an agreement with the European School of Engineers in Material Engineering (EEIGM, in the French acronym) for double degree. Two Masters have graduated with this double degree program after performing academic activities at UCS and EEIGM, headquartered in Nancy, France.
Regarding scientific production, more than 300 articles were published in international journals by faculty and students of the program in its 10 years of existence.
Impact of the research on the industry
From the beginning, the PGMAT-UCS team has pursued the interaction with local companies, based on the affinity that Science and Engineering of Materials have with almost all industrial segments. Thus, already in 2003, the UCS faculty involved in creating the program had visited companies of Caxias do Sul to appraise their needs.
On several occasions throughout its history, PGMAT-UCS could count on resources of companies and entities of the industrial sector, especially the Union of Metallurgical, Mechanics and Electric Equipment Industries of Caxias do Sul (SIMECS), which complemented the public funds in the purchase of equipment for the laboratories of the program.
Inauguration of the Laboratory for Surface Engineering and Thermal Treatments in 2007: local industry was there. Speaking, professor Baumvol.
In 10 years of existence, PGMAT-UCS has graduated 90 Masters. Among them, 45% work in local companies, 10% are academics and 30% are ongoing or concluded their Doctorate degree.
In some cases, the own Master’s research works were essential to the development of new products in the region. This was the case with the Celtrav®, a high-performance material to be used in springs and stops, which composes the product portfolio of the company Travi. A Masters research at PGMAT was also important in developing a coating for ornaments used by the footwear manufacturer Grendene. According to the company, about 18 million pairs of shoes with these ornaments were sold in 2013.
Young entrepreneurs who founded companies from works developed at PGMAT are also among the students and graduates of the program. Plasmar Tecnologia, one of these spin-off companies, currently provides service for hundreds of industries in the region with plasma-based surface treatments that improve the performance and the cycle life of molds, matrices and other parts and components. The other example is Fineza, a company recently created, dedicated to manufacturing and commercializing products for housing and kitchen with decorative coatings that had been optimized in a PGMAT master’s thesis.
The scientific paper by members of the Brazilian community on Materials research featured this month is:
T. E. P. Bueno, D. E. Parreiras, G. F. M. Gomes, S. Michea, R. L. Rodríguez-Suárez, M. S. Araújo Filho, W. A. A. Macedo, K. Krambrock and R. Paniago.Noncollinear ferromagnetic easy axes in Py/Ru/FeCo/IrMn spin valves induced by oblique deposition. Appl. Phys. Lett. 104, 242404 (2014). DOI: 10.1063/1.4883886.
Accurate engineering in spin valves manufacturing
The production and characterization of spin valves is the theme of a collaborative work between Brazil and Chile, whose results were published recently in the prestigious journal Applied Physics Letters (APL).
Spin valves are devices consisting of three or more layers of nanometric thickness composing a sandwich of magnetic and non-magnetic materials. Sensors consisting of such structures fulfill a fundamental role in reading the information written on the hard disc drives, among other applications.
The operation of spin valves is based on an effect called “giant magnetoresistance”, which was the reason behind the Nobel Prize in Physics in 2007. The giant magnetoresistance of spin valve consists of a large change in the electrical resistance in response to the action of a magnetic field. This resistance depends on the relative orientation among the magnetization of the magnetic material layers.
The magnetization of a magnetic material is determined by the orientation of the spins of its electrons. Electrons have two intrinsic features: electric charge and magnetic moment, the latter known as spin. Explore the degree of freedom of the electron spin in addition to its charge led to the emergence of a new field of research called spintronics.
Then, on giant magnetoresistance of spin valves, when the layers of magnetic material have the same direction of magnetization, the device reduces its electrical resistance and becomes a better conductor of electricity. When the magnetic layers acquire opposite directions of magnetization, a significant increase of electrical resistance occurs.
For better understand this effect and, later, the results presented in the article of APL, it is important to remember that the magnetization is a vector physical quantity and that, therefore, besides having an intensity, it has a direction (parallel, perpendicular) and an orientation (indicated by the arrowhead representing the vector). Usually, metallic multilayers composed of magnetic materials separated by a non-magnetic layer, as spin valves, have the magnetization of ferromagnetic layers coupled, says Thiago Bueno, first author of the APL article and PhD student in Physics at the Brazilian Federal University of Minas Gerais (UFMG), supervised by professor Roberto Magalhães Padilla. This coupling can result in parallel magnetization (called “collinear”) with same or opposite orientations, and also in non-collinear magnetization.
Ferromagnetic layers “making a sandwich” with a non-magnetic layer of ruthenium. The red and green arrows represent the direction and the way of magnetization of layers composed by Py and FeCo, respectively. (a) Parallel magnetizations with equal orientation; (b) Parallel magnetizations with opposite orientation; (c) Perpendicular magnetizations.
However, to magnetize the magnetic layers of the spin valve does not occur homogeneously in all directions; they feature the so-called magnetic anisotropy. “The magnetic anisotropy is an important magnetic property, because it establishes an easy direction of magnetization,” says Thiago Bueno. “This property is determined by a number of factors, including the types of materials, the thickness of layers, and the details of the method of sample manufacturing”.
On the work that originated the APL article, the team of scientists has made some adjustments to the method of spin valves manufacturing, obtaining interesting results on the properties of these devices.
Controlling the direction of magnetization
“This work was only possible due to the great collaboration between the parties along the preparation of samples of excellent quality, accurate experimental measures, interpretation of the data, until the publication of the results,” says Thiago Bueno.
Initially, at the Brazilian Center for Development of Nuclear Technology (CDTN in Portuguese) the team has made thin films composed of multi-layers with thickness of a few tens of nanometers. The films were obtained through the technique known as magnetron sputtering, in which argon ions are accelerated against the targets that contain the materials to be deposited, ripping off its atoms. With the aid of magnetrons, these atoms are deposited on a substrate, forming the layers of films. “Through this technique it is possible to obtain films with well-determined chemical composition, thickness and structural morphology,” says Thiago Bueno.
Oblique deposition scheme with 5 sputtering sources (magnetrons) producing an angle of 72 between them. The (β) angle between the direction of deposition and normal direction of the film is estimated at 38° for all sources.
In this study, the scientists set up an oblique deposition scheme by putting the magnetrons making an angle of 72o between them and inclined towards the sample. Using the oblique deposition scheme, scientists made spin valves with ferromagnetic layers up to 10nm-thickness, composed of metallic alloys (Py and FeCo), and separated by a non-magnetic layer of ruthenium (Ru) of thickness between 1nm and 3.5nm. The devices were characterized in the Physics Department at UFMG using ferromagnetic resonance (FMR), an extremely sensitive technique that provides relevant information on the magnetization of materials.
After the interpretation of experimental results, which involved researchers from the Pontifical Catholic University of Chile, the scientists concluded that the oblique deposition induced non-parallel magnetization directions (non-collinear) on ferromagnetic layers of manufactured spin valves. “The angle between the easy axes, approximately equal to the angle between the magnetrons, was determined by the manufacturing geometry”, reinforces the author, Bueno. “One of the main contributions of our work is the demonstration that it is possible to manufacture spin valves where the axes of easy magnetization of ferromagnetic layers (Py and FeCo) are non-collinear,” he sums up.
According to the doctoral student, at the beginning of the work the authors already knew the oblique deposition effects in ferromagnetic/anti-ferromagnetic bilayers. With this study, the team took a step further and has investigated these effects in a more complex structure, the spin valve.
“We believe that our work will compel other researchers into manufacturing these devices, seeking new magnetic configurations between layers of the spin valve “, says Bueno.
“Luminescence applied to nanomedicine” is the subject of one of the plenary lectures that the Materials research community is going to enjoy in our XIII SBPMat Meeting (João Pessoa, Brazil, September 28th to October the 2nd). The speaker will be the Portuguese physicist Luís António Ferreira Martins Dias Carlos, full professor at the University of Aveiro (Portugal), who got his Ph.D. in physics from the University of Évora (Portugal) in 1995 working on photoluminescence of polymer electrolytes incorporating lanthanide salts.
At the University of Aveiro, Luís Carlos created in 2000 a research group in functional organic-inorganic hybrids. The group has established an international network devoted to these luminescent hybrid materials with more than 30 research groups in Europe, China, Japan, Singapore, Brazil and Australia. Also at Aveiro, Luís Carlos has been, since 2009, the vice-director of the Centre for Research in Ceramics and Composite Materials (CICECO), one of the largest European institutes in the Materials and Nano fields.
He is member of the Lisbon Academy of Sciences (Physics section) since 2011. He was visiting professor of São Paulo State University (UNESP), Brazil, in 1999, 2012 and 2013, and of University of Montpellier 2, France, in 2008. He awarded a ‘Pesquisador Visitante Especial’ grant by the CNPq, Science Without Borders Program, Brazil in 2013.
He has co-authored more than 345 papers in international journals, 8 invited reviews, 5 book chapters, and 2 international patents. He has more than 8.050 citations, having h-index of 47. He has given 40 plenary and invited lectures at conferences. He is associate editor of the Journal of Luminescence.
Read our interview with the plenary speaker.
SBPMat newsletter: – Are there nanomedical applications to luminescent materials already on the market/spread in society? Please, give some high-impact examples.
Luís Carlos: – Undoubtedly yes, there are luminescent materials with important applications in nanomedicine already on the market. I can highlight two examples:
1. Organic complexes based on lanthanide ions (as, for example, cryptates and β-diketonates) are sold as contrast agents for magnetic resonance imaging (essentially using Gd³+) and luminescent markers (using Eu3+, Sm3+ and Tb3+) for fluoroimmunoassays. The fluoroimmunoassay is an immunological method for clinical diagnosis that is particularly relevant in prenatal and neonatal screening tests, as well as to detect proteins, viruses, antibodies, tumor biomarkers and medicine residues. In this respect, it is worth mentioning the work conducted by several researchers from the INCT INAMI (Brazilian National Institute of Science and Technology on Nanotechnology for Integrated Markers), implementing a prototype in the hospital environment in order to develop methods to diagnose the American cutaneous leishmaniasis, prostate cancer (PSA) and low density lipoprotein (LDL) by fluoroimmunoassay, using recombinant antigens marked with lanthanide ions complexes (for example, Eu3+, Tb3+ and Nd3+). The international market for contrast agents and luminescent markers based on lanthanide ions is valued in many hundreds of millions of US dollars.
2. Luminescent nanoparticles (“quantum dots”, QDs, and nanocrystals incorporating lanthanide ions) have played a major role in the last years thanks to very important applications for diagnosis by optical imaging and therapy techniques. Recent estimates value the international market for luminescent nanoparticles in the medical field in over 20 million US dollars. A notable example in the treatment of tumors is the local hyperthermia. Local hyperthermia, also referred as local thermotherapy, is a type of treatment in which biological tissues (typically cancer cells) are exposed to temperatures above 45° C, irreversibly damaging them and causing their death (the collateral damage to the healthy tissues surrounding the tumor is usually minimal). Numerous clinical trials with hyperthermia are being currently performed around the world so we can better comprehend and improve the technique. For example, the use of luminescent or magneto-luminescent particles (with magnetic ions such as Iron or Cobalt), vectored to bind to specific points in the cancer cells, enabling the local heating by the absorption of electromagnetic radiation and magnetic induction, respectively, is a new type of local hyperthermia. Precise temperature control in the irradiated area, limiting the effects of high temperature on the rest of the body, still is one of the key challenges for the popularization of the technique.
SBPMat newsletter: – Could you briefly describe the main challenges in the field of luminescence applied to nanomedicine?
Luís Carlos: – I can point out two examples: improving the imaging techniques for diagnosis and developing luminescent micro/nanothermometers which allow mapping the intracellular temperatures with a resolution of the order of tenths of a degree.
In regard to imaging applications in nanomedicine, emitting centers in the near-infrared region (for example, lanthanide ions such as Nd3+ and Yb3+, QDs and organic dyes) have great advantages over those in the visible region. For instance, biological tissues present less autofluorescence in the near-infrared window, which enables a better signal-to-noise discrimination and improves the sensibility to detection. Also, in comparison to the ones in the visible region, near-infrared photons interact less with biological tissues, which reduces the risk of disturbance or damage in the observed biological system. Thus, there is no doubt that the synthesis of new luminescent nanoparticles, emitting efficiently in near-infrared (in some cases producing persistent luminescence, i.e., light emissions that last for minutes, hours or even days, after the excitation is over), will lead us to a revolution in fluorescence microscopy, with the development of in vitro and in vivo imaging techniques in near-infrared (whose radiation penetrates deeper into the biological tissue, when compared to visible light).
The development of luminescent micro/nanothermometers to map the intracellular temperature, particularly in cancer cells, will surely improve our current perception on their pathology and physiology, optimizing early diagnosis and therapeutic processes (as seen above in the case of local hyperthermia). These non-invasive thermometers are a critical tool for better understanding a set of cellular processes followed by alterations in temperature, such as cell division, gene expression, or changes in the metabolic activity. Finally, the development of luminescent nanothermometers in the near-infrared region, which are capable of sensing heat and penetrate deeper into the biological tissue, will pave the way for in vivo thermal sensing and imaging (in small animals, in a first stage).
SBPMat newsletter: – Under your viewpoint, which are the main contributions you made to the field of Materials Science and Engineering during your scientific career? Could you please include a selection of 3 or 4 of the most important publications among your work in your answer?
Luís Carlos: – Normally, our latest works tend to seem to be the most important… Regardless, I understand that my main contributions to Materials Science and Engineering are related to the development of i) luminescent organic-inorganic hybrid materials, ii) ratiometric nanothermometers based on the characteristic emission of lanthanide ion pairs (Eu3+/Tb3+ and Er3+/Yb3+) and iii) nanoplatforms combining nanoheaters (metal particles of Gold or Silver) and nanothermometers which allow to increase the local temperature by laser irradiation while simultaneously mapping such temperature increase with precision. The following four papers illustrate these contributions:
Full Colour Phosphors From Eu(III)-Based Organosilicates. L. D. Carlos, Y. Messaddeq, H. F. Brito, R. A. Sá Ferreira, V. de Zea Bermudez, S. J. L. Ribeiro, Adv. Mater. 12, 594–598 (2000)
Nanoscopic Photoluminescence Memory as a Fingerprint of Complexity in Self-Assembled Alkylene/Siloxane Hybrids. L. D. Carlos, V. de Zea Bermudez, V. S. Amaral, S. C. Nunes, N. J. O. Silva, R. A. Sá Ferreira, J. Rocha, C. V. Santilli, D. Ostrovskii, Adv. Mater. 19 341–348 (2007)
A Luminescent Molecular Thermometer for Long-Term Absolute Temperature Measurements at the Nanoscale. C. D. S. Brites, P. P. Lima, N. J. O. Silva, A. Millán, V. S. Amaral, F. Palacio, L. D. Carlos, Adv. Mater. 22, 4499–4504 (2010)
All-In-One Optical Heater-Thermometer Nanoplatform Operative From 300 to 2000 K Based on Er3+ Emission and Blackbody Radiation. M. L. Debasu, D. Ananias, I. Pastoriza-Santos, L. M. Liz-Marzan, J. Rocha, L. D. Carlos, Adv. Mater. 25, 4868–4874 (2013)
