Current Topics

Chemical and Biological Sensors

Near-Infrared Emissive Oligomeric and Polymeric Dyes for Cancer Imaging

BODIPY-based Conjugated Polymers for Solar Cell Applications

Skills for Job Hunting

Current Topics:

Design and synthesis of donor-pi-acceptor organic dyes with high molar extinction and longer wavelength absorption at greater than 600 nm for solar cell applications, and synthesis, characterization and biomedical applications of conjugated polymers bearing a variety of carbohydrates, cancer-homing peptides, DNA, RNA and PNA aptamers, glycodendrimers, glyconanopaticles, carbon dots, and small organic molecules as fluorescent probes for detection of pH, NADH, enzymes, hypoxia, reactive oxygen, nitrogen and sulfur species.

Carbohydrates play important roles in key recognition events with a variety of receptor proteins such as hormones, enzymes, toxins, lectins, antibodies, viruses, and bacteria. They are also involved in numerous biological processes such as cell growth, recognition and differentiation, cancer metastasis, inflammation, bacterial and viral infection. These specific interactions occur through glycoproteins, glycolipids, and polysaccharide displays found on cell surfaces and proteins with carbohydrate-binding domains called lectins through cooperative multiple interactions since it is known that individual carbohydrate-protein interactions are generally weak. We are developing new approaches to study carbohydrate-protein interactions for biosensing applications for bacteria, toxins, virus, and cancer cells.

Fluorescent conjugated glycopolymers, which combine fluorescent scaffolding and carbohydrate reporting functions into one package, provide very useful means to study carbohydrate-protein interaction for biosensing applications because of their intrinsic fluorescence and their high sensitivity to minor external stimuli due to amplification by a cooperative system response. We have developed prepolymerization and postpolymerization functionalization approaches to quickly attach different carbohydrates to fluorescent conjugated polymers through thioether bridges for well-defined conjugated glycopolymers such as fluorene-based conjugated glycopolymers, glycopolythiophenes and glycopoly(p-phenylene)s.  We are preparing different highly water-soluble well-defined fluorescent conjugated glycopolymers bearing a variety of carbohydrates for biosensing applications.

Fluorescent Probes and Theranostics:

My research focuses on developing pioneering fluorescent probes and theranostics to advance cancer imaging and targeted chemotherapy. My core mission is designing sophisticated molecular platforms capable of monitoring prodrug delivery and precisely targeting cancer cells. This work is guided by exploiting the unique physiological hallmarks of the tumor microenvironment, including hypoxia, acidic pH, elevated NAD(P)H, high levels of reactive oxygen, nitrogen, and sulfur species (ROS, RNS and RSS), and increased viscosity. By strategically harnessing these pivotal cancer-specific factors, my research bridges diagnostics and therapy to enable new paradigms in cancer treatment. Our unwavering goal is creating transformative fluorescent probes and theranostics that facilitate more effective, personalized, and less toxic cancer care. Through interdisciplinary collaboration and cutting-edge molecular design, we aim to engineer innovative tools poised to profoundly impact the future of cancer imaging and therapy. Significantly, my research has consistently received uninterrupted support from the National Institutes of Health (NIH), validating the importance of this work. I was honored to receive recognition from Research.com as one of the leading scientists in chemistry, achieving notable rankings of 2750 in the United States and 9523 globally. This acknowledgement was further underscored by a remarkable h-index of 54 and an i10 index of 136, bolstered by a substantial total of 9214 citations for my work. Overall, I am dedicated to leveraging our expertise in precision molecular engineering to craft the next generation of smart fluorescent probes and theranostics for targeted cancer detection and treatment.

1. Hypoxia: Low oxygen levels promote cancer progression and treatment resistance. We design fluorescent probes sensitive to hypoxia to visualize and quantify hypoxic regions within tumors. These probes also serve as triggers to release chemotherapeutic prodrugs specifically in the hypoxic tumor core.

2. Elevated glutathione (GSH): Cancer cells overexpress GSH, enabling chemotherapy resistance. We create probes to monitor intracellular GSH dynamics and trigger prodrug release in response to high GSH, enhancing treatment specificity.

3. Acidic pH: The acidic tumor microenvironment results from cancer cell metabolism. We develop pH-responsive probes to precisely target acidic regions and control therapeutic payload delivery to tumors while sparing healthy tissue.

4. High NAD(P)H levels: Many cancer cells exhibit increased NAD(P)H levels compared to normal cells. We design fluorescent probes that can detect high NAD(P)H as a tumor-specific marker and use this signal to activate targeted drug delivery.

By targeting these critical tumor-specific factors, my research bridges diagnostics and therapy to pioneer new cancer treatment paradigms. We are driven to create transformative fluorescent probes and theranostics to enable more effective, personalized, and less toxic cancer care. Through interdisciplinary collaboration and cutting-edge molecular design, we strive to develop innovative tools that will significantly impact the future of cancer imaging and chemotherapy.

Near-Infrared Emissive Oligomeric and Polymeric Dyes for Cancer Imaging:

We are developing highly water-soluble near-infrared emissive BODIPY oligomeric and polymeric dyes for cancer imaging. We have also obtained a series of highly water-soluble BODIPY dyes with controllable fluorescence quantum yields.

BODIPY-based Conjugated Polymers for Solar Cell Applications:

Our research efforts have yielded a diverse range of deep-red and near-infrared emissive BODIPY polymeric dyes, tailored for applications in solar cells.

Below, you'll find a selection of BODIPY-based conjugated polymers that have emerged from our work:

Donor-π-Acceptor Organic Dyes for Solar Cell Applications

We are in the process of synthesizing a series of donor-π-acceptor organic dyes characterized by exceptionally high molar extinction coefficients and absorption wavelengths exceeding 600 nm, all tailored for their specific suitability in solar cell applications.

Effective Job-Hunting Skills:

1. Within our group, students thrive in an intellectually stimulating environment fostered by the interdisciplinary nature of our research endeavors.

2. You will acquire expertise in experiment design for testing scientific hypotheses, utilizing an array of analytical methodologies including HPLC, UV-visible absorption spectrophotometry, fluorescence spectroscopy, fluorescence confocal microscopy, and electrochemistry.

3. Additionally, you will hone your skills in multi-step organic and polymer synthesis, as well as the characterization of organic dyes and conjugated fluorescence polymers. This will involve utilizing advanced techniques such as GC-MS, LC-MS, NMR, infrared spectroscopy, MALDI-TOF mass spectrometry, and gel permeation chromatography. Furthermore, you will engage in fluorescence cellular imaging to detect various analytes, including different metal ions, anions, pH levels, enzymes, coenzymes (NADH and NADPH), and reactive oxygen, nitrogen, and sulfur species in live cells, employing confocal fluorescence microscopy.

Most Ph.D. students within our research group have demonstrated exceptional academic productivity during their doctoral studies, boasting a track record of publishing over 18 research articles in reputable international peer-reviewed journals. Their scholarly impact is further underscored by impressive h-index values, ranging from 15 to 19. After obtaining their Ph.D. degrees from Michigan Tech, several members of our group pursued postdoctoral research positions at esteemed institutions. Dr. Jingtuo Zhang and Dr. Giri Kumar Vegesna conducted their postdoctoral research at the University of California, Berkeley, while Dr. Mingxi Fang and Dr. Venkat Donuru pursued their postdoctoral studies at renowned institutions, including Stanford University and Pennsylvania State University, respectively. Beyond their academic achievements, some of our alumni have ventured into leadership roles within prominent biotechnology companies, demonstrating their capacity to excel not only in academia but also in the corporate sector. Overall, our trainees have compiled outstanding research and career records, validating the productivity and impact of their doctoral training. Please refer to the publications of our group members on the group member page.