Toxicity effects of reflectin nanoparticles in keratinocyte cells

• Main Author: Lim, Felicia Jia Jia
• Other Authors: Ali Gilles Tchenguise Miserez
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Biomaterials
• Online Access: https://hdl.handle.net/10356/165772
• Institution: Nanyang Technological University

UV radiation has been proven to be detrimental to health due to genotoxicity. To mitigate this, sunscreen was developed with compounds that could absorb, reflect, or scatter UV radiation. Over the past decades, nanoparticles have been used in sunscreen formulations to reduce the white cast while providing more effective absorption or scattering of UV radiation. However, the long-term side effects of applying sunscreen formulated with nanoparticles such as TiO2 and ZnO are largely unknown. These safety concerns have led to a need to find an alternative biocompatible UV filter that utilises biomaterial and has similar or lower toxicity than metal oxides. In this project, the cytotoxicity of Sepioteuthis lessoniana reflectin nanoparticles in keratinocyte cells and the UV absorbance of the conjugated SIRF nanoparticles were evaluated as a potential biocompatible UV filter. Plasmid transformation was carried out on E. coli. Recombinant E. coli was cultured to synthesize reflectin protein which was extracted by lysing and purified using HPLC. The sizes of reflectin nanoparticles were successfully controlled by varying ACN and reflectin concentrations during self-assembly, conjugated with DBCO through click chemistry and stabilized using Azido PEG3-OH. After self-assembly, DLS was used to characterize the hydrodynamic diameter of nanoparticles. Cytotoxicity tests on keratinocyte cells were conducted using varying sizes and concentrations of DBCO-SIRF B1, ZnO and TiO2 nanoparticles over 24 h. Cell viability assays carried out showed that DBCO-SIRF-B1 had similar or lower toxicity than TiO2 controls of similar sizes and lower toxicity than ZnO controls. UV absorbance of DBCO-SIRF-B1 was analysed and showed strong UV absorbance in UVC region, which is different from TiO2 extracted from commercial sunscreen. Hence, it can be concluded that since the size of DBCO-SIRF-B1 can be controlled and it has relatively low cytotoxicity, it can potentially be used as a biocompatible UV filter. However, further experimentation to conjugate new molecules that absorb UVA and UVB radiation for more effective UV protection is required as the UV absorbance range is not satisfactory.