Daniel Wehrung, Elaheh. A. Chamsaz, James H. Andrews, Abraham Joy, and Moses O. Oyewumi, “Engineering Alkoxyphenacyl-Polycarbonate Nanoparticles for Potential Application in Near-Infrared Light-Modulated Drug Delivery via Photon Up-Conversion Process,” Journal of Nanoscience and Nanotechnology 17, 4867-4881 (2017).
This publication describes the results of experiments primarily done at NEOMED, but also at YSU’s Dept. of Physics & Astronomy, using nano-crystals to convert near infrared light to ultraviolet light. Typically, ultraviolet light is difficult to apply as a form of medical phototherapy due to its harmful effects to other tissues. Using the materials studied in this paper, the primary exposure would instead be to infrared light that is then converted to ultraviolet at the site of the phototherapy for localized treatment. This work was led by Daniel Wehrung as part of his successful PhD dissertation work at NEOMED under the supervision of Dr. Moses Oyewumi in the Department of Pharmaceutical Sciences. Dr. Andrews assisted with experiments at YSU as part of this study.
Photoresponsive delivery systems that are activated by high energy photo-triggers have been accorded much attention because of the capability of achieving reliable photoreactions at short irradiation times. However, the application of a high energy photo-trigger (UV light) is not clinically viable. Meanwhile, the process of photon-upconversion is an effective strategy to generate a high energy photo-trigger in-situ through exposure to clinically relevant near-infrared (NIR) light. In this regard, we synthesized photon upconverting nanocrystals (UCNCs) that were subsequently loaded into photoresponsive nanoparticles (NPs) prepared using alkoxyphenacyl-based polycar- bonate homopolymer (UCNC-APP-NPs). UCNC loading affected resultant NP size, size distribu- tion, colloidal stability but not the zeta potential. The efficiency of NIR-modulated drug delivery was impacted by the heterogenetic nature of the resultant UCNC-APP-NPs which was plausibly formed through a combination of UCNC entrapment within the polymeric NP matrix and nucleation of polymer coating on the surface of the UCNCs. The biocompatibility of UCNC-APP-NPs was demonstrated through cytotoxicity, macrophage activation, and red blood cell lysis assays. Studies in tumor-bearing (nu/nu) athymic mice showed a negligible distribution of UCNC-APP-NPs to retic- uloendothelial tissues. Further, distribution of UCNC-APP-NPs to various tissues was in the order (highest to lowest): Lungs > Tumor > Kidneys > Liver > Spleen > Brain > Blood > Heart. In all, the work highlighted some important factors that may influence the effectiveness, reproducibility biocompatibility of drug delivery systems that operate on the process of photon-upconversion.