Biomaterials: From Synthesis to Applications

Our group is interested in developing advanced functional materials that could be applied in regenerative medicine, drug delivery, and at the interface with biological tissues. In particular, we focus on electrically conducting polymers. These are synthetic macromolecules that have demonstrated a broad variety of controlled properties including chemical, optical and electronic characteristics. Our interest in these polymers lies in their application as polymeric scaffolds applied in tissue engineering and as biocompatible materials at the biotic/abiotic interface.
 
Our research provides an excellent multidisciplinary environment that is built on a cohesive research framework whereby chemistry, physics, material science, biology and biomedical engineering partner together for the development of advanced functional biomaterials.

Conducting polymers at the biotic/abiotic interface: 

This research area focuses on developing conducting polymer based constructs with enhanced electronic stability and testing their functionality at the biotic/abiotic interface. 
 
By careful design of the chemical interactions between the conducting polymer, the dopant and other components in the device, we have recently developed a free-standing conductive patch with demonstrated electronic stability, and appropriate physical properties of a biomaterial. 
 
In collaboration with Imperial College London, the patch was tested in cardiac models and found to alter the conduction signal across the heart wall.  
 
In collaboration with Dr Antonio Lauto (University of Western Sydney), we tailored the chemistry of our electronically stable patch so that it can be bonded to tissue photo-chemically instead of using sutures. 
 
Current investigations are focussed on unravelling the mechanism of interaction between the conductive material and electroresponsive tissue, as well as enhancing material properties for better integration with the host.
 

Conducting polymers in tissue engineering: 

These research investigations focus on developing processable conducting polymers with end or side functionalities by chemical polymerization. 
 
The field of tissue engineering aims at restoring a biological function through the design of smart materials that mimic the properties of the native extracellular matrix. One of the last decade’s challenges has been the fabrication of tissue-engineered scaffolds for electro-responsive organs such as the heart and neural system. The scaffold should not only match the mechanical properties of the native tissue, but it should be electronically conductive to aid the tissue regain its functionality. Conducting polymers are being considered as the structural components for the fabrication of electroconductive hydrated scaffolds. However, most current designs focus on growing non-functional conducting polymers in a hydrophilic polymeric matrix, limiting control over the scaffold properties. 
 
Our material design strategy transitions from monomeric building blocks modified with appropriate functional groups, to processable conjugated polymers with functional pendant chains.  The side functionalities allow post-functionalization of the polymer to be tailored for desired scaffold requirements. The chemical design is complimented by scaffold fabrication, characterisation techniques and in vitro cell studies.  


Conducting polymers in drug delivery: 

Our research approach is to design conductive systems that disassemble in a controlled fashion and exploit their potential in drug delivery applications. 
 
Conducting polymers are of growing importance in the medical field with potential applications in tissue engineering, drug delivery, bioactuators, and biosensors.    Since attracting interest as suitable matrices in biomedical applications,   there have been pioneering efforts to replace the permanent non-degradable conducting polymer matrices with a degradable biocompatible material.   
 
To achieve this, we synthesise water soluble polyelectrolytes based on conjugated backbones. We employ the layer by layer technique to fabricate multilayered films. The disassembly of these systems can be either passive governed by the diffusion of buffer ions into the system or active by inducing a potential and changing the oxidation state of the conjugated polymers. The assembly and disassembly of an electronically conducting polyelectrolyte structure in a programmable manner is an attractive architectural feature for bionic devices. We are in particular interested in investigating this feature for drug delivery applications. 
 

Relevant Publications:

Frost, S.J., Mawad, D., Ruprai, H., Higgins, M.J., Kuchel, R., Tilley, R., Myers, S., Hook, J., Lauto, A. Gecko–inspired chitosan adhesive for tissue repair. NPG Asia Materials. Accepted
 
Mawad, D., Lauto A., Wallace G.G. “Conductive Polymer Hydrogels”, Chapter 2, In: Polymeric Hydrogels as Smart Biomaterials, Editor: Kalia, S., Springer Series on Polymer and Composite Materials, Springer International Publishing AG Switzerland, pp: 19-44, 2016.
 
Frost, S.J., Mawad, D., Hook, J., Lauto, A. Micro- and nanostructured biomaterials for sutureless tissue repair. Advanced Healthcare Materials, 2016, 5, pp. 401-414.
 
Mahat, M.M., Mawad, D., Nelson, G.W., Fearn, S., Palgrave, R.G., Payne, D.J., Stevens, M.M. Elucidating the deprotonation of polyaniline films by X-ray photoelectron spectroscopy. Journal of Materials Chemistry C, 2015, 3 (27), pp. 7180-7186. 
 
Mawad, D., Warren, C., Barton, M., Mahns, D., Morley, J., Pham, B.T.T., Pham, N.T.H., Kueh, S., Lauto, A. Lysozyme depolymerization of photo-activated chitosan adhesive films. Carbohydrate Polymers, 2015, 121, pp. 56-63.  
 
Mawad, D., Molino, P.J., Gambhir, S., Locke, J.M., Officer, D.L., Wallace, G.G. Electrically induced disassembly of electroactive multilayer films fabricated from water soluble polythiophenes. Advanced Functional Materials, 2012, 22 (23), pp. 5020-5027. 
 
Mawad, D., Stewart, E., Officer, D.L., Romeo, T., Wagner, P., Wagner, K., Wallace, G.G. A single component conducting polymer hydrogel as a scaffold for tissue engineering. Advanced Functional Materials, 2012, 22 (13), pp. 2692-2699. 
 
Lauto, A., Stoodley, M., Barton, M., Morley, J.W., Mahns, D.A., Longo, L., Mawad, D. Fabrication and application of rose bengal-chitosan films in laser tissue repair. Journal of visualized experiments: JoVE, 2012, 68. 
 
Mawad, D., Gilmore, K., Molino, P., Wagner, K., Wagner, P., Officer, D.L., Wallace, G.G. An erodible polythiophene-based composite for biomedical applications. Journal of Materials Chemistry, 2011, 21 (15), pp. 5555-5560. 
 
Lauto, A., Mawad, D., Barton, M., Gupta, A., Piller, S.C., Hook, J. Photochemical tissue bonding with chitosan adhesive films. BioMedical Engineering Online, 2011, 9, art. no. 47.