Tayyaba Hasan, Ph.D.

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- (i) light of appropriate wavelength,
- (ii) a light activatable chemical compound (photosensitizer or PS),
- (iii) molecular oxygen.
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- Targeted PDT of tumors: Specificity in PDT emanates from:
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- (i) preferential localization of the photosensitizer in tissues of interest,
- (ii) spatial localization of the activating light. Nano-construct formulations of PS are being used to increase accumulation within the tumor. The site directed localization, combined with selective irradiation, results in a dual selectivity that minimizes normal tissue damage. Additional selectivity is achieved using targeting moieties such as antibodies and peptides.
- Site-directed PDT of Microorganisms:
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- (i) Infectious Diseases: The emergence of clinical isolates that are resistant to standard antimicrobial chemotherapeutics provides the necessary impetus to develop treatments that are not hindered by microbial resistant mutants. PDT has a potential to be that treatment due to its acute nature of photokilling. We are developing microbial-specific photosensitizers for use in PDT that exploits the β-lactamase-producing phenotype of drug resistant pathogens.
- (ii) Rapid Fluorescence based assay for Antibiotic Efficacy: A β-lactamase sensitive PS has been constructed to result in a probe that, when cleaved (<30 min) produces a strong fluorescence signal.
- (iii) Cutaneous Leishmaniasis: Our interest is in the development of selective phototherapeutic agents for improved outcome.
- Mechanism-based PDT combination therapies: We are interested in the biological consequences of PDT at both the cellular and molecular level. Our lab is developing mechanism-based PDT combination treatments in which one treatment will nullify the tumor survival responses resulting from the other treatment. The strategies involve nano carriers with multiple inhibitors of oncogenic pathways.
- Image-guided therapeutics: Understanding targeting and treatment effects is a key bottleneck in the development of new drugs and PDT treatment protocols. These projects include:
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- (i) in vivo longitudinal quantification of disease progression and drug targeting via confocal microendoscopy,
- (ii) drug uptake information of individual organs and tissues using in vivo fluorescence imaging of whole small animals,
- (iii) non-invasive monitoring of in vivo tumor volume, vasculature, and oxygenation using ultrasound/photoacoustic imaging, and
- (iv) on-line, non-invasive fluorescent monitoring of cytotoxic singlet oxygen generation during PDT for personalizing PDT dose parameters in the clinic.
- Model Development: Biological inadequacies in the 2D cultures and slow speed in animal models is a major barrier for evaluation of a broad array of combination treatments. Our laboratory is developing heterocellular 3D models with quantitative imaging as a viable, rapid platform for testing a larger variety of combination strategies, combined with biomarker monitoring by high throughput imaging and acoustic cell printing. This work provides a platform for evaluating therapies for a broad array of cancers.
On the subject of cancers, Dr Hasan focuses on treating and diagnosing malignancies in ovarian, pancreatic, and head and neck cancers.
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On the subject of infections and infectious diseases, Dr Hasan targets developing microbial-enzyme-specific photoactivatable molecules for use in PDT. Organisms in infectious diseases that she examines include leishmaniasis, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus.
In addition, Dr Hasan uses optimal imaging strategies to develop target-specific molecular probes for in situ monitoring of cellular processes during treatment such as the up-regulation of vascular endothelial growth factor.
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- Targeted PDT of tumors: Specificity in PDT emanates from: