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Discipline:
Subcategory: Materials Science
Lewis Lott - Delaware State University
Co-Author(s): Cherese Winstead and Kimberley Milligan, Department of Chemistry, Delaware State University, Dover, DE Katie Van Aken, Kathleen Maleski, and Yury Gogotsi, Department of Material Science and Engineering, Drexel University, Philadelphia, PA
Breast Cancer is the second leading cause of death for women. One of the main issues stems from the development of genetic alterations in human genes (BRCA1 and BRCA2) causing failure in repairing DNA. Antimicrobial therapy was proven to be unsuccessful as antibiotics are unable to penetrate the MCF-7 cell-lines. Thus, a method of drug delivery is necessary to distribute the required treatment efficiently and safely. Nanodiamonds (NDs), nanomaterials synthesized by detonation have been examined for drug delivery due to low cytotoxicity and harmlessness to cells. However, the surface of NDs has been a challenging feature to manipulate due to existing functional groups which may result in diverse behavior and performance. In this study, we have examined the functionalization of NDs by specific functional groups such as amine NDs (N-NDs) and carboxylated NDs (C-NDs). Additionally, the surface was also modified by the introduction of the biopolymer, chitosan (CS) which was targeted to see the electrostatic attraction of the negatively charged C-NDs with the positively charged CS biopolymer. X-Ray diffraction was performed to observe crystallinity of ND structures by identifying the lattices structures (h, k, and l values). Peak shifts to the right demonstrated a tensile stress for CS-C-NDs in comparison to C-NDs. Fourier Transform infrared spectroscopy (FTIR) intensity peaks increased for the C-NDs with the CS biopolymer sample, suggesting that ND-biopolymer composites have the ability to effectively display biocompatibility features to enhance future drug delivery methods. ND particles typically aggregate into much larger groups >200 nm, which are too large for drug delivery applications. Therefore, in order to physically separate the ND aggregates, salt assisted attrition milling was utilized to decrease the particle size. After 5 hours of milling, dynamic light scattering measurements revealed an average size of 127 nm, which was roughly 10% smaller than the average particle size of the original C-NDs, effectively decreasing the size of the aggregate, thus increasing of surface area for the binding of CS. In conclusion, this study revealed that milling amine and C-NDs could provide necessary methods to produce materials used in intracellular drug delivery system.
Funder Acknowledgement(s): I would like to thank the Bridge to Doctorate Fellowship that has been offered to help me complete this research. I want to acknowledge my advisor Dr. Winstead and Dr. Milligan for their much needed guidance and assistance in regards to this excellent research experiment. I would also like to thank Yury Gogotsi, Katie Van Duren, and Kathleen Maleski for offering assistance in the Material Science and Engineering Lab located in Drexel University.
Faculty Advisor: Cherese Winstead, Cwinstead@desu.edu
Role: I characterized Carboxylated (C-NDs) and Amine (N-NDs) nanodiamonds (NDs) using FTIR, XRD, TGA, and DSC. After the characterization methods were performed, the surfaces of the C-NDs were synthesized using a biopolymer, chitosan. Furthermore, I was able to mill both raw NDs down to a more applicable size using the salt assisted ball milling machine to enhance drug delivery. Using a five hour process, I milled C-NDs to increase surface area to volume, which was displayed via dynamic light scattering (DLS). Based on XRD analysis, I confirmed that the shift of the peaks to the right displayed tensile stress showing that there was surface modification on C-NDs and that the chitosan peak actually developed a more amorphous appearance proving that there was surface modification on C-NDs.
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