title: Design of Novel Nanomaterials for Cellular Drug Delivery and Toxicity
Creators: name: Saunders, Ashley
Publisher: name: The Open University
Year: 2024

description: Nanoparticles possess the potential to enhance many areas of medicine owing to their unique physiochemical properties and ease of manipulation during synthesis. Gold nanoparticles are of particular interest for use as radiosensitizers or drug carriers as they possess relatively low cytotoxicity and can be easily functionalized to allow for addition of specific targeting ligands such as peptides. The aim of this project was to explore the synthesis of different kinds of gold nanoparticle for a range of uses. Gelatine coated nanoparticles were synthesized and assessed as potential radiosensitizers and peptide bound nanoparticles were produced as a means to achieve enhanced uptake across the blood brain barrier into the brain.

Gelatine coated gold nanoparticles were explored for their potential future use as a radiosensitiser. The synthesis and characterization of these nanoparticles was analyzed through UV-vis spectroscopy, electrophoresis and dynamic light scattering (DLS). Transmission electron microscopy (TEM) was used to show the presence and subsequent enzymatic removal of the gelatine layer encapsulating the gold nanoparticle core. Experiments using different radical probes were used to determine whether the gelatine layer reduced radical formation while intact and an increase in radical formation when removed, but did not show any conclusive evidence that this was occurring. Instead results indicated the presence of excess gelatine in the nanoparticle solutions which may have masked any enhanced radical formation from the AuNPs.

Peptide bound nanoparticles were synthesized via exchange reactions with glyconanoparticles using a transferrin receptor targeting peptide. The characterization of these particles using electrophoresis and fast protein liquid chromatography (FPLC) provided no evidence that the peptide ligand bound successfully to the surface of the gold nanoparticles. A VCAM-1 targeting peptide was also exchanged with glyconanoparticles reactions and was shown to successfully bind to the surface of the gold nanoparticles, producing different populations of particles with varying amounts of peptide attached. TEM was used to measure the size distribution of these particles before examining their uptake in D3 human brain endothelial cells. 

VCAM-1 bound nanoparticles were assessed in cellular uptake assays using D3 cells. TEM was used to measure the number of nanoparticles present in the cells after incubation in addition to their localization. Results indicated that overall, there was a higher uptake of VCAM-1 bound nanoparticles when compared to a glyconanoparticle control and a control using a VCAM-1 peptide with a randomized sequence. Temperature, however, did not impact the levels of nanoparticle uptake. 

In conclusion it was demonstrated that it was possible to produce gold nanoparticles encapsulated by gelatine but that further investigation was needed to confirm the removal of gelatine from the nanoparticles and the AuNPs radiosensitising effects. Gold nanoparticles with a VCAM-1 receptor targeting peptide bound to the surface showed promise in being a useful carrier to the brain with enhanced uptake into D3 cells.