Abstract

Title
Controlling hybrid systems

Abstract
The main biopolymers of the extracellular matrix (ECM) – collagen, proteoglycans, fibronectin and elastin – rarely exist as single entities in living tissue. Although each polymer network provides its own biochemical signal, these networks respond simultaneously to mechanical stimuli. One example of this mechanical synergy can be observed during the process of material reconstitution, which is a fundamental process for many of the biological studies that focus on the interaction between cells and the ECM in three-dimensional (3D) biology. When some of the most commonly used ECM materials are reconstituted in vitro as single entities, cell encapsulation in 3D becomes a challenge. This is exemplified by the slow process of collagen network formation and the weak mechanical properties of hyaluronic acid (HA). In this work, we demonstrate that the mechanical properties of collagen and HA networks can be controlled by establishing interpenetrating networks (IPNs) with synthetic, semi-flexible hydrogels - polyisocyanopeptides (PIC). We utilise rheology and confocal microscopy to evaluate both the formation and mechanical synergy between the materials and we further demonstrate the application of the novel IPNs for studying cellular behaviour and morphology in 3D using high-resolution, live-cell microscopy.

Title
Nanomaterials from inorganic to polymeric nanoparticles for biomedical applications

Abstract
Nanoparticles are widely used in various biomedical applications, especially in disease diagnosis and treatment. Generally, these nanoparticles can be divided into two classes, inorganic nanoparticles and polymeric nanoparticles. Each of them features multiple subclasses with different properties for specific biomedical applications. For instance, inorganic nanoparticles such as gold nanoparticles, which are the most well studied, possess theragnostic capability owing to their unique plasmonic properties. The polymeric nanoparticles normally demonstrate good biocompatibility, biodegradability, and drug loading capability, making them ideal for cancer imaging and therapy. However, these nanoparticles without appropriate designs would suffer a rapid in vivo clearance upon administration, significantly restricting their in vivo applications. Thus, it is important to develop new classes of nanoparticles with enhanced pharmacokinetic profile to improve their efficacy in biomedical applications. Herein, we reported how innovative chemical design can be utilized to tailor the function and properties of nanoparticles including inorganic and polymeric nanoparticles for improved biomedical applications. For inorganic nanoparticles, we reported the synthesis, characterization, and application of gold nanorods coated with highly hydrophilic sulfoxide-containing polymers. The gold nanorods coated with sulfoxide polymers displayed much reduced cellular uptake by macrophages and prolonged in vivo circulation time. Additionally, these gold nanorods displayed promising photothermal therapy effect in ablating 4T1 breast cancer cells and photoacoustic imaging capability. The results demonstrate that the gold nanorods coated with sulfoxide polymers are promising as nanotheranostic agents for cancer treatment with enhanced efficacy. For polymeric nanoparticles, we reported the synthesis of fluorinated nanoparticles with controlled size, shape and high fluorine contents using a method called polymerization-induced self-assembly. Both spherical and worm-like fluorinated nanoparticles were obtained, which displayed high in vitro and in vivo sensitivity for 19F magnetic resonance imaging. Interestingly, the fluorinated nanoparticles with different morphologies possessed different behaviour in terms of cellular uptake, pharmacokinetics as well as biodistribution profile. The results show that these fluorinated nanoparticles have great potential for a wide range of bioapplications such as imaging and therapy.

Bio

Marco completed his degree in Biotechnology (Honours I) with a major in nanotechnology from The University of Queensland and he is a current PhD student under the supervision of Prof. Alan Rowan, Dr Jan Lauko (AIBN) and Dr. Samantha Stehbens (IMB). He works at the interface of materials science and cell biology having been initially trained as an experimental chemist. During his higher degree research, he underwent combined training in soft matter, molecular cell biology and live-cell microscopy in order to understand the fundamental principles that govern the mechanical interplay between cellular behaviour (migration and adhesion) and natural materials.

Yixin Chang received her bachelor and master’s degree in Chemistry at Jilin University. In January 2020, she started her PhD at the Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland under the supervision of Prof. Andrew Whittaker, Dr Changkui Fu, Dr Hui Peng and Dr Gayathri Ediriweera. Her research focuses on the synthesis and characterization of theranostic nanoparticles for biomedical applications.

 

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