Date of Award
Dr. Joseph Bradshaw
Dr. Martin D. "Marty" Perry
Dr. Tim Knight
Currently, advances in the area of photodynamic therapy (PDT) using porphyrin molecules are being made and not only in this arena, but in science and society overall, nanoparticles are of high interest. For perspective on the size of nanoscale products (such as porphyrins or quantum dots) present in society today, consider that 2 g of 100 nm-diameter nanoparticles contains enough material to provide every human worldwide with 300,000 particles each (Hardman 2006). Porphyrins are better suited for PDT than their organic dye predecessors due to their fluorescence intensity and longevity. Currently, Photofrin® and Visudyne®, both porphyrin-type derivatives are used in PDT. However, the fluorescence and longevity advantages could possibly be further improved by the successful coupling of the porphyrin molecule to nanoparticles known as quantum dots (QDs). QDs, types of phosphors, are miniscule crystals of semiconductor material such as zinc sulfide, cadmium sulfide, cadmium telluride, or cadmium selenide, with their overall structure being composed of a core surrounded by an outer shell. The nature of QDs may be altered upon modification of or additions to this outer shell - including the attachment of porphyrin molecules (Zenkevich 2006). The resulting QD-porphyrin complex is expected to have increased photo-efficiency and more selective biological cell imaging. Porphyrins are known to be tumor specific and therefore the QD-porphyrin complex should be as well.
Continuing research may include the addition of zinc to the porphyrin complex followed by attempted coupling with QDs. A second area of further research will include the addition of hexadiamine through the aide of a BOC protecting group followed by attempted coupling with QDs, as well as investigations concerning the cellular uptake of many of these QD-porphyrin compounds.
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Singleton, Kenley C., "Connect the Dots: Coupling Quantum Dots with Water-Soluble Porphyrins" (2009). Honors Theses. 77.