Friday, 11 August 11:00am – 12:00pm

This seminar will be delivered in Chemistry Lecture Theatre 4 and Online (Zoom) Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Dr Vien Huynh, Key Centre for Polymers and Colloids (KCPC), School of Chemistry

Host: Dr David Nguyen

Title: Novel and Scalable Polymer Coated Nanomaterials for Efficient Delivery of Anticancer Drug/Active Ingredients

Abstract: Developing a safe and efficient drug delivery system for cancer treatment poses a significant challenge, as it requires specifically targeting tumor cells while sparing healthy cells and organs. Recently, graphene oxide (GO) has emerged as a promising candidate due to its low toxicity and high surface area, enabling increased drug loading capacity. However, GO itself is not stable in physiological conditions and necessitates surface modifications for biological applications.

To address this, we present a convenient and scalable approach utilizing RAFT-controlled polymerization for surface modification. In our study, we describe a straightforward method to produce partially polymer-coated individual GO sheets using RAFT-mediated free radical emulsion polymerization. Anionic macro-RAFT copolymers comprising a block of butyl acrylate, acrylic acid, sulfonated monomers, and a steric stabilizer block were employed to disperse GO sheets in an aqueous solution. The resulting macro-RAFT-stabilized GO was subsequently coated by starve-feeding a mixture of methyl methacrylate and butyl acrylate, resulting in a rough surface with bare and uncoated sites available for drug adsorption. The material exhibited stability in physiological conditions and demonstrated high drug loading capacity, with approximately 100% weight of Doxorubicin (Dox) being adsorbed, possibly through hydrogen bonding and π-π stacking interactions. The Dox-loaded polymer-coated GO exhibited penetration into spheroids (3D cell models) and triggered drug release in the presence of locally present reducing agents.

Additionally, we investigated the polymer coating of chlorothalonil (CTN), a widely used as a non-systemic fungicide in crop protection. CTN has known acute inhalation toxicity, primarily through respiratory irritancy. Therefore, reducing inhalation toxicity while maintaining fungicidal activity is highly desirable. By employing RAFT-mediated emulsion polymerization, we achieved tunable coating thickness on CTN particles, enabling a significant reduction in inhalation toxicity. Remarkably, this reduction in toxicity did not compromise the fungicidal activity of CTN.

Bio: Dr. Vien Huynh is currently employed as a Research Fellow at the Key Centre for Polymers and Colloids (KCPC) within the School of Chemistry at the University of Sydney. Presently, he is involved in a research project sponsored by Ferronova, which centers around the development of sterically stabilized superparamagnetic iron oxide nanoparticles (SPIONs) for the purpose of detecting and treating cancer. Before commencing this project, Dr. Huynh dedicated more than ten years of his career to studying the application of polymer coatings on active ingredients, particularly agrochemicals. This research endeavor was entirely supported by Syngenta Crop Protection.

In addition to his work on the Ferronova-funded project, Dr. Huynh collaborates on several other research initiatives funded by various industries such as Gelion, Nucleotrace, Opxflo, etc. These projects involve a diverse range of responsibilities, including proposal writing, conducting proof-of-concept experiments, optimizing processes to facilitate technology transfer, and scaling up production. His research contributes solutions to challenging problems encountered in the fields of agrochemicals, drug/active ingredient delivery, energy storage, microplastics and recycling materials.

During his pursuit of a Ph.D. in polymer chemistry, Dr. Huynh was honored with an esteemed Endeavour Postgraduate Scholarship. This scholarship enabled him to undertake his doctoral studies at the Centre of Advanced Macromolecular Design (CAMD) within the School of Chemical Engineering at the University of New South Wales, under the guidance of Professor Martina Stenzel.