AIBN Seminar Series HDR

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Dan Cheng Abstract

Cellular delivery of DNA using silica nanoparticles has attracted great attention. Typically, polyethyleneimine (PEI) is used to form a silica/PEI composite vector. Understanding the interactions at the silica and PEI interface is important for successful DNA delivery and transfection, especially for silica with different surface functionality. Herein, we report that a higher content of hydrogen bonding formed between PEI molecules and phosphonate modified silica nanoparticles could slow down the PEI dissolution from the freeze-dried solid composites into aqueous solution than the bare silica counterpart. The pronounced PEI retention ability through phosphonation of silica nanoparticles effectively improves the transfection efficiency due to the high DNA binding affinity extracellularly, effective lysosome escape and high nuclear entry of both PEI and DNA intracellularly. Our study provides a fundamental understanding on designing effective silica-PEI-based nano-vectors for DNA delivery applications.

Dan Cheng Bio

Dan Cheng is a PhD student under the supervision of Prof. Chengzhong Yu and Dr. Hao Song in AIBN at the University of Queensland. She got her bachelor's and master's degrees from Beijing University of Chemical Technology in China. She specializes in synthesis of novel nanomaterials via self-assembling of silica and polymer and their application in the field of DNA delivery.

Lauren Geurds Abstract

Conductive hydrogels based on metallic nanoparticles (MNPs) are heavily explored due to their outstanding conductive properties and extensive applications in different industries, including biosensors, flexible electrodes, and optoelectronics. However, the production of well-oriented MNPs in hydrogels is challenging. Due to the high surface area and interaction energy, MNPs tend to aggregate, limiting their ability to be homogeneously dispersed into a polymer, leading to poor electrical conductivity and mechanical properties. Using a one-component system, such as cellulose nanocrystals (CNC) templated polymer brushes for the guided formation of MNPs, could solve current limitations. CNC is the primary building block of plants and gained significant attention as a sustainable and biodegradable material with numerous chemically accessible hydroxyl groups, allowing the stabilization of MNPs and controllable mechanical properties. Here we demonstrate an optimized approach for introducing block-copolymers on the CNC using surface-initiated Atom Transfer Radical Polymerisation (SI-ATRP) and click chemistry. By tuning the polymer brush density and length, templating ability and mechanical properties can be fine-tuned to obtain desired characteristics. Furthermore, understanding how these parameters impact each other will guide the future tailoring of the surface modification and evaluate the potential of CNC-grafted polymer brushes for the guided formation of MNPs as a potential conductive printable ink. 

Lauren Guerds Bio

Lauren Geurds completed her B.Sc. in chemistry at the HAN University of Applied Sciences, The Netherlands. In 2019, she received a second B.Sc. with Honours class I in the field of biochemistry at the University of Queensland, Australia. In January 2020, she started her PhD in the Australian Institute for Bioengineering and Nanotechnology (AIBN) at the University of Queensland under the supervision of Dr Nasim Amiralian, Prof Alan Rowan, and Dr Jan Lauko.