Peptide-targeted gold nanostars for treatment of Parkinson's disease

Lead Research Organisation: Imperial College London
Department Name: Materials

Abstract

Introduction
Current research for an effective therapeutic for neurodegerative disorders is hindered by the limiting ability to cross the blood-brain barrier, rapid degradation, side effects and high cost. New neurotrophic motifs have been recently identified from within the S100 protein family that have demonstrated neuronal protection capabilities in brain injury/PD models. This project will focus on engineering efficient brain penetrable gold nanoparticles to be used as a delivery system for these novel neuroprotective peptides as a potential therapeutic.

Objectives
1. Develop and optimise high quality and optically tunable gold (Au) nanoparticles of various sizes and morphologies.
2. Conjugate the novel peptides to the Au nanoparticles.
3. Determine the biocompability properties of the novel S100A4 peptides: 'H3/H6' on neurons when attached to nanoparticles (neuroprotective/neurotoxicity).
4. Characterise the interface between the nanoparticles and neurons using electron microscopy.
5. Optimise the peptide-nanoparticle blood-brain barrier crossing.
6. Develop and optimise silica nanoparticles and nanoflowers.
7. Optimise conjugation of the peptides to the L-DOPA functionalised silica nanoparticles/nanoflowers.
The first year focused on the synthesis and characterisation of spherical and star shaped gold nanoparticles, leading to the conjugation of the neuroprotective peptides. ICP and TEM analysis was used to determine the surface area of the particles that enabled me to calculate the quantity of peptide molecules the particles could accommodate. UV-Vis was used to determine peptide attachment and NanoDrop to determine protein concentration to enable dose specific treatments. These conjugates were then tested for biocompatibility studies. As year two of this research project comes to an end, I am able to confirm that the peptides conjugates demonstrated a significant effect on neurite outgrowth, confirmed they are not neurotoxic and, moreover, rescue neurons from H2O2 -induced oxidative stress (a lead cause of cell death in Parkinson's disease). To view the interaction between the nanoparticles and the neurons, the neurons were treated with the conjugates, fixed, and then embedded in epoxy resin. Various embedding techniques and resins were used to find the optimum environment to allow the best images via electron microscopy. At present I am using different imaging techniques to gain the best possible images to determine how the nanoparticles interact with the neurons. These comprise of TEM, cryo-TEM, tomography, SEM and FIB-SEM analysis. The results so far were just presented as a poster at the BioMedEng18 conference (6-7th September), and when I have the desired interaction image(s) a paper will be sent for publication. Silica particles will be generated as a comparison to gold with the potential to be more bio-friendly.

The Novelty

As neurons grow, they develop into neuronal networks, we propose that star shaped gold particles or silica nanoflowers will be the optimal drug delivery system as the drug is activated via receptor binding and downstream pathway from then on. Therefore, the peptides only need to be delivered to the neuronal membranes. The nanostars/flowers potentially have the ability to intertwine in the neuronal network, therefore, come into contact with a lot more neurons and thus have a more wide spread effect. No research to date has published any effects of using star shaped particles as drug delivery systems to the brain - only nanospheres or rods. This method of drug delivery is also non-invasive and have proven can cross the blood brain barrier.3

Key papers:

1. Dmytriyeva, O., et al (2012). Nature Communications. 3 article 1197
2. Pankratova, S., et al (2018). Theranostics. 8 (14) 3977-3990
3. Gonzalez-Carter, D, et al (2018). Nanomedicine. In Press

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509486/1 01/10/2016 30/09/2021
1857820 Studentship EP/N509486/1 01/10/2016 30/09/2020 Corinne Morfill