Roger M. Leblanc - US grants

This award from the Chemistry Research Instrumentation and Facilities Program (CRIF) will assist the Department of Chemistry at University of Miami acquire a scanning probe microscope (SPM). This equipment will enhance research in a number of areas including the following: (1) monolayers of fullerene derivatives, (2) electrochemistry of supramolecular systems, (3) Langmuir and Langmuir-Blodgett films, (4) scanning probe microscopic studies of triazine-barbiturate hydrogen bonded self-assembled complexes, and (5) chemical and enzymatic synthesis of oligosaccharides-diacetylene lipid conjugates. The scanning probe microscope (SPM) enables researchers to image atoms directly. The technique uses the piezoelectric effect which involves bringing an extremely sharp metal needle within a few angstroms of the sample surface. The distance is small enough for electrons to leak or tunnel across the gap and generate a minute current. As the gap between the tip and the sample increases, the current decreases. As then probe crosses the sample, moving back and forth across its surface, it traces out a contour map of the sample's surface atoms. The AFM is used in the control of material used to fabricate semiconductor circuits >¥?Á? ?Á¢Á/??© ?> _/>` Â?Á%?¢ ? ?©Á_?¢¥?`

With this award from the Chemistry Research Instrumentation and Facilities (CRIF) Program, the Department of Chemistry at the University of Miami will acquire a 500 MHz NMR Spectrometer. This equipment will enable researchers to carry out studies on a) fullerene derivatives and the higher fullerenes; b) structural studies of alpha-aminoorganolithiums; c) natural products from marine algae; and d) novel redox self-assembling systems.

Nuclear Magnetic Resonance (NMR) spectroscopy is the most powerful tool available to chemists for the elucidation of the structure of molecules. It is used to identify unknown substances, to characterize specific arrangements of atoms within molecules, and to study the dynamics of interactions between molecules in solution. Access to state-of-the-art NMR spectrometry is essential to chemists who are carrying out frontier research. The results from these NMR studies will have an impact in a number of areas including materials chemistry.

With support from the Chemistry Research Instrumentation and Facilities (CRIF) Program, the Department of Chemistry at the University of Miami will acquire a MALDI-TOF Mass Spectrometer. This equipment will enhance research in a number of areas including a) electrochemical transformations of fullerenes; b) novel redox self-assembling systems; c) chemical analysis of complex urban aerosols; d) oligonucleotide sequencing and micro-array biochip probe analysis of fungal species; and e) characterization of novel porphyrin arrays.

Mass spectrometry (MS) is a technique used to probe intimate structural details and to obtain the molecular compositions of a vast array of organic, bioorganic, and organometallic molecules. The results from these studies will have an impact in a number of areas including materials chemistry, air quality and biology.

9981375
Leblanc

This proposal supports a three year collaborative research project between Professor Roger Leblanc of the University of Miami and Professor Takeshi Hasegawa of the Kobe Pharmaceutical University in Japan. The researchers will be undertaking a study of the molecular recognition formed in systematic molecular assemblies. Infrared spectroscopy is a powerful technique to study the molecular structures and interactions of organized Langmuir monolayers and LB films. The specific aim is to study the molecular recognition formed in systematic molecular assemblies at the air-water interface. The researchers plan to develop a biosensor for the detection and monitoring of hazardous chemicals to human health using the Langmuir-Blodgett film technique. The study will include both fundamental investigation and prototype development.

The project brings together the efforts of two laboratories that have complementary expertise and research capabilities. The planned activities are the focusing points in surface science and material science research aimed at the advanced development of nanotechnology. Results of this research should lead to a better and healthier environment. This research advances international human resources through the participation of a postdoc and graduate student. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. The researchers plan to publish results of the research in scientific journals.

This award to Dr. Roger Leblanc of the University of Miami is supported by the Analytical and Surface Chemsitry Program. The research focuses on the development of surfaces, based on Langmuir-Blodgett techniques, which have high specificity for target biomolecules, and would be used for sensor development. The research is multi-disciplinary and will include the areas of synthesis, interfacial chemistry and analytical chemistry (sensor development and characterization). The key qoals of the project are 1) synthesis of a lipid/organic monolayer at the water/air interface using combinatorial chemistry, 2) determine the monolayer specificity toward target biomolecules, 3) determine whether the specificity of the monolayer be enhanced by using target templates during the synthesis, and 4) use the sensor with actual biological systems.

This is a novel research proposal at the frontier of biosensor development. It has a degree of risk, however, the investigator makes a concerted effort to address the potential problems. The potential for involvement of minority students is high. The impact of this research will be felt in the areas of combinatorial synthesis, biochemistry, surface chemistry and sensor development. In the future, there is potential for societal impact if sensor applications develop in biological systems.

Professor Roger Leblanc of the University of Miami is supported by the Analytical and Surface Chemistry Program to utilize a two-dimensional combinatorial chemistry technique to produce novel bioactive surfaces. The idea is to utilize engineered peptide lipids spread at an air/water interface. In project one, it is considered that if enough combinations of these species are present, there should on average be aligned peptide sections that mimic active sites of actual enzymes. The first target is Acetylcholinesterase. In the second project, the aggregation of beta-amyloid in two dimensions will be explored. New molecules that act as beta-sheet breakers will be sought. A third project is to study peptide-capped fluorescent quantum dots as possible optical biosensors. Monolayer techniques, FTIR spectroscopy, atomic force microscopy and scanning electron microscopy will be used in the studies.

This work lies in the areas of molecular recognition, signaling and biosensors. Studying amyloid protein aggregation and understanding its precise mechanism will enable rational design of beta-sheet breakers that are putative drugs for preventing Alzheimer's disease. Many of the applications of nanoparticles have been held back due to stability issues in aqueous environments, and the approaches here could serve to lengthen lifetimes and ruggedness of designed particles. In addition, underrepresented minority students are included within summer experiences at this Hispanic Serving Institute.

This is a proposal to acquire an atomic force microscope (AFM) on an inverted optical microscope and to develop two AFM-related non-imaging instruments: one for measuring single-molecule force spectroscopy and inter-molecular forces; the other, for measuring elasticities of soft samples under physiological conditions at the nano-scale. Over the past 10 years, atomic force microscopy (AFM) has become an increasingly important tool in biological research. It has gained popularity in biological applications because, unlike electron microscopy, it can image samples under physiological conditions, including live cells undergoing biological processes. The AFM acquires a topographical image of the sample surface by raster scanning an atomically sharp probe over the sample. In addition to its different imaging modes, the AFM is a versatile instrument that can be applied as a nano-indenter and as a molecular force apparatus to probe the mechanical properties of the sample. As a nano-indenter, the AFM has provided direct measurements of the local viscoelastic properties of samples on the nanometer scale. As a molecular force apparatus, the AFM has been used to measure the unbinding force of individual ligand-receptor complexes and the unfolding of individual proteins. Another attractive feature of the AFM is that it can be readily combined with optical microscopy techniques such as FRET, FRAP, TIRF and confocal microscopy. By integrating optical microscopy and AFM into a single experimental platform, the optical image can be directly correlated with the AFM data, providing a powerful tool for studying biological process in situ and in real time.

The acquisition and development of these three instruments is the first step toward establishing an ultramicroscopy center at the university. The two instruments to be developed can be constructed very economically, based on the designs of existing AFMs from the principal investigator's laboratory; this will permit the commercial AFM to be dedicated to imaging applications. The commercial AFM will be the first imaging AFM in the South Florida area and will provide a much needed resource for the local research community. These instruments will provide valuable research opportunities for undergraduates and students from underrepresented groups as well as researchers from different disciplines within the university.

0944290
Leblanc

In the United States of America heart disease is the leading cause of death. Nearly 2500 Americans die of cardiovascular disease each day, which claims more lives than cancer, chronic respiratory diseases, accidents, and diabetes mellitus combined. Human cardiac troponin I (cTnI) is superior to other biomarkers in the diagnosis of myocardial infarction due to its specificity. The overall objective of the proposed research is the detection of cTnI based on the fluorescence spectroscopic technique using a chemically-modified quartz slide with a mutant monoclonal mouse IgG.

The specific aims are:
(i) Surface chemistry characterization of IgG mutants at the air-water interface;
(ii) Surface modification of a solid substrate suitable for the chemical attachment of the mutant IgG;
(iii) Detection of cTnI using fluorescence spectroscopic technique of the chemically-attached mutant IgG-fluorophore.

Accomplishment of this proposed project will provide a revolutionary route for earlier and faster diagnosis using this biomarker. It will open a new avenue to directly detect the cTnI in a blood sample instead of the plasma and serum samples commonly used with spectroscopic techniques such as surface plasmon resonance spectroscopy. The transformative nature of this project lies in its innovative approach of detection using a chemically-attached mutant IgG.

The proposal seeks to develop and optimize a novel approach for detection of a blood borne marker (Troponin I) associated with cardiovascular disease. This biomarker has been shown to have predictive value in diagnosis of myocardial infarctions. Therefore, it is important to monitor such biomarker rapidly and onsite - either in the first responder vehicle or in the emergency room. This proposal addresses the need for rapid detection of troponin by simplifying traditional sandwich immunoassay/ELISA used for analysis of this biomarker. This simplified assay will use just one antibody/one step for detection of troponin and will involve a novel mutant antibody oriented on the surfaces of the biosensor in a controlled manner. Troponin binding to this to this fluorescently labeled antibody will result in the change of fluorescence intensity. Successful completion of this project may lead to future development of biosensor for rapid, point of care diagnosis of myocardial infarctions.

NON-TECHNICAL ABSTRACT

This project advances our understanding of Carbon dots (C-dots) physical and chemical properties for their application in biological systems. Size, morphology, surface chemistry and method of preparation govern how C-dots interact with biological tissues. C-dots derived from carbon powder are unique in that they bind to mineralized bones with high affinity and specificity. By characterizing the physical and chemical properties that confer these C-dots their unique bone-binding properties, this project will advance our understanding of the interactions between C-dots and mineralized tissues. This is an essential step towards developing C-dots as tools for bone imaging and diagnostic tools, and for the treatment and repair of bone fractures and degenerative diseases (e.g., osteoporosis) that would impact US health. Additionally, this work will support the training of graduate and undergraduate students, fostering inquiry-based research and scientific collaboration essential to develop the skills needed in a thriving US scientific workforce.

TECHNICAL ABSTRACT

The goal of this work is to understand the physical and chemical properties of Carbon nanoparticles (C-dots) for their development as bone-specific drug carriers. C-dots are a new emerging class of nanomaterials whose biological applications in imaging, diagnostics and therapeutics critically depend on their size, molecular structure and material of origin. One particular class of C-dots synthesized from carbon powder have the unique property of binding to mineralized bones in vivo. To advance our understanding of the interactions between C-dots and mineralized tissues this project will (1) determine the intrinsic chemical and physical properties of C-dots that are related to their high affinity and specificity towards mineralized bones, (2) determine how different surface functionalities influence the interactions between C-dots and mineralized bones, and (3) functionally test the ability of C-dots to deliver drugs to bones. By characterizing C-dots' unique bone binding properties, this work will not only uncover the physicochemical principles that allow C-dots binding to bones, but will also discern the molecular principles need to target new nanomaterials to mineralized tissue at the exclusion of other tissues. Thus, the findings of this work will have broad intellectual implications for nanomaterial chemistry and engineering, as well as advancing the development of bone imaging and diagnostic tools for the repair and treatment of bone fractures and degenerative diseases.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Coronavirus disease 2019 (COVID-19) is caused by the novel coronavirus (SARS-CoV-2). This disease is a critical problem that concerns everyone?s health and safety. As of July 15th, 2020, it has caused more than 580,000 deaths worldwide, and it is predicted to recur in the near future. At this time there is no cure to COVID-19 and traditional chemotherapy faces a series of challenges including: (1) the ability of SARS-CoV-2 to mutate readily; (2) ineffective antibodies; and (3) inadmissibility of most therapeutic agents across the blood-brain barrier. Consequently, this combination of factors gives SARS-CoV-2 an opportunity to hide in the brain, replicating and posing a lingering threat to the human body when its immune system becomes weak. Therefore, it is of great importance to come up with a treatment using the tools of biomedical engineering to prevent viral entry. In this project carbon dots, a class of novel nanoparticles that can cross the blood-brain barrier, will be utilized as versatile nanocarriers for various antibodies and an antiviral drug, remdesivir, that has been used to treat COVID-19. This method will make use of models comprised of specialized host cells and viruses to simulate the infection process of SARS-CoV-2. The outcomes of this project could lead to studies in which a great number of viral diseases can be treated with nanoparticles and therapeutic agents using the methodology introduced in this work. On the educational front, the project will provide training experiences for undergraduate and graduate students in a range of research methods, including surface chemistry, spectroscopy, nanomaterials, bioanalysis, nanocarriers, and bionanotechnology. Outreach activities include working with the media and TV to promote science and technology and participating with the Miami Frost Science Museum to curate exhibits and promote science to the general public.

The goal of this research project is to design a novel biomedical system that applies carbon dots (CDs) as therapeutic nanocarriers. The carbon dots will be conjugated with antibodies of the spike proteins on SARS-CoV-2 (CD-NAbs), antibodies of the angiotensin-converting enzyme 2 (ACE2) receptors on host cells (CD-BAbs), and remdesivir. A novel disease model comprised of pseudohost cells and pseudoviruses will be developed used to analyze the inhibition effectiveness of the carbon dot conjugates. The effectiveness of separate and combined delivery of the carbon dot-antibody conjugates will be compared by measuring their IC50. The research idea is that CD-NAbs and CD-BAbs can respectively interact with the pseudoviruses and the pseudohost cells. The presence of carbon dot conjugates will reduce the binding of SARS-CoV-2 to the surface of host cells by steric effects and electrostatic repulsive forces. With the help of ACE2 BAbs, carbon dot conjugates will be able to deliver remdesivir into the infected cells to prevent viral replication. The results from this research project are expected to provide fundamental insights into whether and how long carbon dot conjugates will keep SARS-CoV-2 from infecting the host cells by reducing their available binding sites and inhibiting the approach of the virus to the cells.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.