Honors College Theses

Publication Date



Biochemistry (B.S.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Dr. Ria Ramoutar


Photodynamic therapy (PDT) is considered to be a potential replacement for traditional methods of chemotherapy. It includes the administration of photosensitizing agents (PS), which generate reactive oxygen species (ROS) upon excitation at a specific wavelength. With new outlooks and techniques, cancer research is advancing each day. It has allowed the progress of several theranostic drug delivery systems (DDS) exploring the area of nanomedicine.2 In the present work, a Rhodamine derivative, Rhodamine 6G (R6G) was used as the PS. In general, rhodamine compounds undergo cytotoxic reactions on photoexcitation by electron transfer reactions with folic acid within cells, making them a favorable PS. However, rhodamines often experience poor water solubility which limits their applications in biological environments. Additionally, the process of PDT requires a high accumulation of photosensitizers. To overcome the challenge of aqueous compatibility of rhodamine compounds as well as retaining its specific functioning in cells at a reduced optimum concentration, this project focused on developing a nanocarrier system using gold nanoparticles (GNPs) to help deliver those dyes to the cancer targets. The GNPs were synthesized with a particle size ranging from 16 to 30 nm. Towards the aim to understand the photodynamic inactivation of cancer cells, absorption and fluorescence spectroscopic techniques were utilized. Dynamic Light Scattering (DLS) spectroscopy has been used to measure the hydrodynamic size of the nanoparticles. UV-Vis and fluorescence spectroscopy analyzed the nanocomposite with the rhodamine derivative and studied the immobilization over time. The 24-hour experiments provided a route for GNP conjugated rhodamine dye towards using PDT as the most viable method.