ORCID Profile
0000-0003-1999-6613
Current Organisation
University of Wollongong
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Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.BIOMATERIALS.2015.07.022
Abstract: The brain is an enormously complex organ structured into various regions of layered tissue. Researchers have attempted to study the brain by modeling the architecture using two dimensional (2D) in vitro cell culturing methods. While those platforms attempt to mimic the in vivo environment, they do not truly resemble the three dimensional (3D) microstructure of neuronal tissues. Development of an accurate in vitro model of the brain remains a significant obstacle to our understanding of the functioning of the brain at the tissue or organ level. To address these obstacles, we demonstrate a new method to bioprint 3D brain-like structures consisting of discrete layers of primary neural cells encapsulated in hydrogels. Brain-like structures were constructed using a bio-ink consisting of a novel peptide-modified biopolymer, gellan gum-RGD (RGD-GG), combined with primary cortical neurons. The ink was optimized for a modified reactive printing process and developed for use in traditional cell culturing facilities without the need for extensive bioprinting equipment. Furthermore the peptide modification of the gellan gum hydrogel was found to have a profound positive effect on primary cell proliferation and network formation. The neural cell viability combined with the support of neural network formation demonstrated the cell supportive nature of the matrix. The facile ability to form discrete cell-containing layers validates the application of this novel printing technique to form complex, layered and viable 3D cell structures. These brain-like structures offer the opportunity to reproduce more accurate 3D in vitro microstructures with applications ranging from cell behavior studies to improving our understanding of brain injuries and neurodegenerative diseases.
Publisher: Elsevier BV
Date: 03-2017
Publisher: IEEE
Date: 2012
Publisher: Elsevier BV
Date: 03-2016
Publisher: Springer Science and Business Media LLC
Date: 11-12-2016
DOI: 10.1557/ADV.2015.9
Publisher: Springer Science and Business Media LLC
Date: 17-06-2011
Publisher: Wiley
Date: 04-07-2017
Publisher: Elsevier BV
Date: 04-2014
Publisher: IEEE
Date: 06-2011
Publisher: Wiley
Date: 10-04-2015
Abstract: A smart valve is created by 4D printing of hydrogels that are both mechanically robust and thermally actuating. The printed hydrogels are made up of an interpenetrating network of alginate and poly(N-isopropylacrylamide). 4D structures are created by printing the "dynamic" hydrogel ink alongside other static materials.
Publisher: MDPI AG
Date: 26-08-2013
DOI: 10.3390/S130911336
Publisher: Elsevier BV
Date: 03-2015
Publisher: IEEE
Date: 06-2011
Publisher: Springer Science and Business Media LLC
Date: 22-09-2011
Publisher: MDPI AG
Date: 04-05-2020
Abstract: While aerial shark spotting has been a standard practice for beach safety for decades, new technologies offer enhanced opportunities, ranging from drones/unmanned aerial vehicles (UAVs) that provide new viewing capabilities, to new apps that provide beachgoers with up-to-date risk analysis before entering the water. This report describes the Sharkeye platform, a first-of-its-kind project to demonstrate personal shark alerting for beachgoers in the water and on land, leveraging innovative UAV image collection, cloud-hosted machine learning detection algorithms, and reporting via smart wearables. To execute, our team developed a novel detection algorithm trained via machine learning based on aerial footage of real sharks and rays collected at local beaches, hosted and deployed the algorithm in the cloud, and integrated push alerts to beachgoers in the water via a shark app to run on smartwatches. The project was successfully trialed in the field in Kiama, Australia, with over 350 detection events recorded, followed by the alerting of multiple smartwatches simultaneously both on land and in the water, and with analysis capable of detecting shark analogues, rays, and surfers in average beach conditions, and all based on ~1 h of training data in total. Additional demonstrations showed potential of the system to enable lifeguard-swimmer communication, and the ability to create a network on demand to enable the platform. Our system was developed to provide swimmers and surfers with immediate information via smart apps, empowering lifeguards/lifesavers and beachgoers to prevent unwanted encounters with wildlife before it happens.
Publisher: Springer Science and Business Media LLC
Date: 27-09-2017
DOI: 10.1007/S10856-017-5979-3
Abstract: Trilayered polypyrrole (PPy) actuators have high stress density, low modulus and have wide potential biological applications including use in artificial muscles and in limb prosthesis after limb utation. This article examines the in vivo biocompatibility of actuators in muscle using rabbit models. The actuators were specially designed with pores to encourage tissue in growth this study also assessed the effect of such pores on the stability of the actuators in vivo. Trilayered PPy actuators were either laser cut with 150 µm pores or left pore-less and implanted into rabbit muscle for 3 days, 2 weeks, 4 weeks and 8 weeks and retrieved subsequently for histological analysis. In a second set of experiments, the cut edges of pores in porous actuator strips were further sealed by PPy after laser cutting to further improve its stability in vivo. Porous actuators with and without PPy sealing of pore edges were implanted intramuscularly for 4 and 8 weeks and assessed with histology. Pore-less actuators incited a mild inflammatory response, becoming progressively walled off by a thin layer of fibrous tissue. Porous actuators showed increased PPy fragmentation and delamination with associated greater foreign body response compared to pore-less actuators. The PPy fragmentation was minimized when the pore edges were sealed off by PPy after laser cutting showing less PPy debris. Laser cutting of the actuators with pores destabilizes the PPy. This can be overcome by sealing the cut edges of the pores with PPy after laser. The findings in this article have implications in future design and manufacturing of PPy actuator for use in vivo.
Publisher: IEEE
Date: 06-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B925456K
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TB01504J
Abstract: Herein we present a simple approach for fabrication of alginate fibers with programmable microsphere concentration gradients for local protein delivery.
Publisher: MDPI AG
Date: 21-01-2021
Abstract: Over the past decade, drones have become a popular tool for wildlife management and research. Drones have shown significant value for animals that were often difficult or dangerous to study using traditional survey methods. In the past five years drone technology has become commonplace for shark research with their use above, and more recently, below the water helping to minimise knowledge gaps about these cryptic species. Drones have enhanced our understanding of shark behaviour and are critically important tools, not only due to the importance and conservation of the animals in the ecosystem, but to also help minimise dangerous encounters with humans. To provide some guidance for their future use in relation to sharks, this review provides an overview of how drones are currently used with critical context for shark monitoring. We show how drones have been used to fill knowledge gaps around fundamental shark behaviours or movements, social interactions, and predation across multiple species and scenarios. We further detail the advancement in technology across sensors, automation, and artificial intelligence that are improving our abilities in data collection and analysis and opening opportunities for shark-related beach safety. An investigation of the shark-based research potential for underwater drones (ROV/AUV) is also provided. Finally, this review provides baseline observations that have been pioneered for shark research and recommendations for how drones might be used to enhance our knowledge in the future.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TB00393H
Abstract: In this review hydrogel-forming polymers that are suitable for extrusion-based 3D printing are evaluated.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2LC40223H
Abstract: We present a novel, low-resource fabrication and assembly method for creating disposable erometric detectors in hybrid paper-polymer devices. Currently, mere paper-based microfluidics is far from being able to achieve the same level of process control and integration as state-of-the-art microfluidic devices made of polymers. To overcome this limitation, in this work both substrate types are synergistically combined through a hybrid, multi-component/multi-material system assembly. Using established inkjet wax printing, we transform the paper into a profoundly hydrophobic substrate in order to create carbon electrodes which are simply patterned from carbon inks via custom made adhesive stencils. By virtue of the compressibility of the paper substrate, the resulting electrode-on-paper hybrids can be directly embedded in conventional, 3D polymeric devices by bonding through an adhesive layer. This manufacturing scheme can be easily recreated with readily available off-the-shelf equipment, and is extremely cost-efficient and rapid with turn-around times of only a few hours.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA07210G
Abstract: Processable graphene olycaprolactone composites for tissue engineering were produced in a simultaneous one-step polymerisation/reduction process without toxic reducing agents.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4LC01002G
Abstract: In this work we present a centrifugal microfluidic system enabling highly efficient collective trapping and alignment of particles such as microbeads and cells, their multi-colour fluorescent detection and subsequent manipulation by optical tweezers.
Publisher: Springer Science and Business Media LLC
Date: 08-11-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0LC00160K
Abstract: A novel active valving technique, whereby paraffin wax plugs in microchannels on a centrifugal microfluidic platform are actuated using focused infrared (IR) radiation is demonstrated in this report. Microchannels were simultaneously or sequentially opened using a stationary IR source by forming wax plugs with similar or differing melting points. The presented wax plugs offer key advantages over current active valving techniques, including a less involved fabrication procedure, a simpler actuation process, and the ability to multiplex experiment with active valves. In addition, a new technique for automated liquid reagent storage and release on the microfluidic disc platform, based on the formation and removal of a wax layer, is demonstrated. Overall, the techniques presented in this report offer novel methods for liquid handling, separation, and storage on the centrifugal microfluidic disc platform.
Publisher: Wiley
Date: 12-10-2012
Abstract: This work demonstrates the design and fabrication of an all cyclo-olefin polymer based microfluidic device capable of capturing magnetic beads and performing electrochemical detection in a series of gold electrodes. The size of chip is of a microscope slide and features six independent measuring cells for multianalyte detection purposes. The aim of this work is to show that rapid prototyping techniques can be instrumental in the development of novel bioassays, particularly in clinical diagnosis applications. We show the successful determination of troponin-T, a cardiac disease marker, in the clinically relevant range of 0.05-1.0 ng/mL. This methodology achieves a detection limit of 0.017 ng/mL in PBS solutions, and is capable of detecting less than 1 ng/mL in a 1:50 human serum dilution.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2LC40722A
Abstract: This work for the first time presents the full integration and automation concept for a range of bioassays leveraged by cascading a centrifugo-pneumatic valving scheme to sequentially move several liquids through shared channel segments for multi-step s le preparation into the detection zone. This novel centrifugo-pneumatic liquid handling significantly simplifies system manufacture by obviating the need for complex surface functionalization procedures or hybrid material integration, as it is common in conventional valving methods such as capillary burst valves or sacrificial valves. Based on the centrifugo-pneumatic valving scheme, this work presents a toolkit of operational elements implementing liquid loading/transfer, metering, mixing and sedimentation in a microstructured polymer disc. As a proof of concept for the broad class of homogeneous bioassays, the full integration and automation of a colorimetric nitrate/nitrite test for the detection of clinically relevant nitric oxide (NO) in whole blood is implemented. First, 40 μL of plasma is extracted from a 100 μL s le of human blood, incubated for one hour with the enzymatic mixture (60 μL), and finally reacted with 100 μL of colorimetric (Greiss) reagents. Following just a single loading phase at the beginning of the process, all of these steps are automated through the centrifugo-pneumatic cascade with a high level of flow control and synchronization. Our system shows good correlation with controls up to 50 μM of nitrate, which adequately covers the healthy human range (4 to 45.3 μM).
Publisher: Elsevier BV
Date: 10-2017
Publisher: American Chemical Society (ACS)
Date: 08-09-2014
DOI: 10.1021/AM503878D
Abstract: An additive manufacturing process that combines digital modeling and 3D printing was used to prepare fiber reinforced hydrogels in a single-step process. The composite materials were fabricated by selectively pattering a combination of alginate/acrylamide gel precursor solution and an epoxy based UV-curable adhesive (Emax 904 Gel-SC) with an extrusion printer. UV irradiation was used to cure the two inks into a single composite material. Spatial control of fiber distribution within the digital models allowed for the fabrication of a series of materials with a spectrum of swelling behavior and mechanical properties with physical characteristics ranging from soft and wet to hard and dry. A comparison with the "rule of mixtures" was used to show that the swollen composite materials adhere to standard composite theory. A prototype meniscus cartilage was prepared to illustrate the potential application in bioengineering.
Publisher: AIP Publishing
Date: 15-04-2009
DOI: 10.1063/1.3110016
Abstract: In the present work, we analyze the capillary filling dynamics in centrifugally actuated microfluidic platforms with dynamically evolving contact line motion for wetting fluids. Special attention is devoted to estimate the effects of variable hydraulic resistances over different flow regimes. Dynamics of the meniscus advancement within the rotating microchannel turns out to be typically nonlinear, in tune with the relative instantaneous strengths of the capillary forces, centrifugal forces, and viscous resistances. Detailed dynamical characteristics of the meniscus evolution are obtained from the approximate semianalytical and full-scale numerical solutions, and are found to agree well with the experimental findings on lab-on-a-compact disk arrangements.
Publisher: Emerald
Date: 05-09-2016
DOI: 10.1108/JMTM-12-2015-0117
Abstract: Company pressure for manufacturers is mounting from two angles: increasing pressure of global competition, and rapid advancements in technology such as additive manufacturing (AM) that are altering the way that goods are manufactured. The purpose of this paper is to explore the adoption process of AM within a manufacturing system and its business impact. Research was conducted to collect empirical data at two manufacturing case companies in the North West England. Both cases are located in areas of industrial recovery using AM engineering innovation for value creation. Early findings showed that the implementation of AM caused a shift in value propositions and the creation of additional value streams (VSs) for the case study companies. AM was shown to compliment and strengthen traditional manufacturing VSs rather than replacing them. Limitations include the generalizability due to the number and location of case companies included in this research. It is worthwhile to explore the opportunities that AM brings with the existing customer base as it has the potential to add unexplored and untapped value. However, managers need to be mindful of the capability and resources required to put the VS into practice. Both cases resulted in skill retainment and development due to the implementation of AM. Hence, the innovation contributed to regional economic recovery and business survival. This empirical research is one of the early field explorations focussing on the impact of AM on VS structures. Hence, this paper contributes to the area of technology enhanced manufacturing systems.
Publisher: Springer Science and Business Media LLC
Date: 2014
DOI: 10.1557/OPL.2014.249
Abstract: The mechanical characteristics of ionic-covalent entanglement hydrogels consisting of combinations of the biopolymers gellan gum and kappa-carrageenan, and the synthetic polymers polyacrylamide and an epoxy amine were investigated. Compression testing showed that these gels exhibited “double network” behavior, i.e. strong tough gels.
Publisher: Elsevier BV
Date: 03-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B913219H
Abstract: The applications of microfluidic technologies in medical diagnostics continue to increase, particularly in the field of nucleic acid diagnostics. While much attention has been focused on the development of nucleic acid lification and detection platforms, s le preparation is often taken for granted or ignored all together. Specifically, little or no consideration is paid to the development of microfluidic systems that efficiently extract nucleic acids from biological s les. Here, a centrifugal microfluidic platform for mechanical s le lysis and homogenization is presented. The system performs s le lysis through a magnetically actuated bead-beating system followed by a centrifugal clarification step. The supernatant is then transferred for extraction using a unique siphon. Several other new microfluidic functions are implemented on this centrifugal platform as well, including s le distribution, a unique hydraulic capillary valve, and self-venting. Additionally, the improved system has features with a small footprint designed specifically for integration with further downstream processing steps. Biological validation of the platform is performed using Bacillus subtilis spores and clinical s les (nasopharyngeal aspirates) for respiratory virus detection. The platform was found to be as efficient as in-tube bead-beating lysis and homogenization for nucleic acid extraction, and capable of processing 4 s les in batch to near PCR-ready products in under 6 min.
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.CBPA.2012.06.002
Abstract: Over the past two decades, centrifugal microfluidic systems have successfully demonstrated their capability for robust, high-performance liquid handling to enable modular, multi-purpose lab-on-a-chip platforms for a wide range of life-science applications. Beyond the handling of homogeneous liquids, the unique, rotationally controlled centrifugal actuation has proven to be specifically advantageous for performing cell and particle handling and assays. In this review we discuss technologies to implement two important steps for cell handling, namely separation and capturing/counting.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B924109D
Abstract: The centrifugal microfluidic platform has been a focus of academic and industrial research efforts for almost 40 years. Primarily targeting biomedical applications, a range of assays have been adapted on the system however, the platform has found limited commercial success as a research or clinical tool. Nonetheless, new developments in centrifugal microfluidic technologies have the potential to establish wide-spread utilization of the platform. This paper presents an in-depth review of the centrifugal microfluidic platform, while highlighting recent progress in the field and outlining the potential for future applications. An overview of centrifugal microfluidic technologies is presented, including descriptions of advantages of the platform as a microfluidic handling system and the principles behind centrifugal fluidic manipulation. The paper also discusses a history of significant centrifugal microfluidic platform developments with an explanation of the evolution of the platform as it pertains to academia and industry. Lastly, we review the few centrifugal microfluidic-based s le-to-answer analysis systems shown to date and examine the challenges to be tackled before the centrifugal platform can be more broadly accepted as a new diagnostic platform. In particular, fully integrated, easy to operate, inexpensive and accurate microfluidic tools in the area of in vitro nucleic acid diagnostics are discussed.
Publisher: IOP Publishing
Date: 23-05-2016
DOI: 10.1088/1758-5090/8/2/025013
Abstract: Tissue engineering scaffolds for nerve regeneration, or artificial nerve conduits, are particularly challenging due to the high level of complexity the structure of the nerve presents. The list of requirements for artificial nerve conduits is long and includes the ability to physically guide nerve growth using physical and chemical cues as well as electrical stimulation. Combining these characteristics into a conduit, while maintaining biocompatibility and biodegradability, has not been satisfactorily achieved by currently employed fabrication techniques. Here we present a method combining pultrusion and wet-spinning techniques facilitating incorporation of pre-formed filaments into ionically crosslinkable hydrogels. This new biofabrication technique allows the incorporation of conducting or drug-laden filaments, controlled guidance channels and living cells into hydrogels, creating new improved conduit designs.
Publisher: IEEE
Date: 2012
Publisher: IOP Publishing
Date: 15-08-2008
DOI: 10.1088/1748-6041/3/3/034116
Abstract: The study of the biocompatible properties of carbon microelectromechanical systems (carbon-MEMS) shows that this new microfabrication technique is a promising approach to create novel platforms for the study of cell physiology. Four different types of substrates were tested, namely, carbon-MEMS on silicon and quartz wafers, indium tin oxide (ITO) coated glass and oxygen-plasma-treated carbon thin films. Two cell lines, murine dermal fibroblasts and neuroblastoma spinal cord hybrid cells (NSC-34) were plated onto the substrates. Both cell lines showed preferential adhesion to the selectively plasma-treated regions in carbon films. Atomic force microscopy and Fourier transform infrared spectroscopy analyses demonstrated that the oxygen-plasma treatment modifies the physical and chemical properties of carbon, thereby enhancing the adsorption of extracellular matrix-forming proteins on its surface. This accounts for the differential adhesion of cells on the plasma-treated areas. As compared to the methods reported to date, this technique achieves alignment of the cells on the carbon electrodes without relying on direct patterning of surface molecules. The results will be used in the future design of novel biochemical sensors, drug screening systems and basic cell physiology research devices.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2LC20973J
Abstract: In this article we introduce a novel technology that utilizes specialized water dissolvable thin films for valving in centrifugal microfluidic systems. In previous work (William Meathrel and Cathy Moritz, IVD Technologies, 2007), dissolvable films (DFs) have been assembled in laminar flow devices to form efficient sacrificial valves where DFs simply open by direct contact with liquid. Here, we build on the original DF valving scheme to leverage sophisticated, merely rotationally actuated vapour barriers and flow control for enabling comprehensive assay integration with low-complexity instrumentation on "lab-on-a-disc" platforms. The advanced sacrificial valving function is achieved by creating an inverted gas-liquid stack upstream of the DF during priming of the system. At low rotational speeds, a pocket of trapped air prevents a surface-tension stabilized liquid plug from wetting the DF membrane. However, high-speed rotation disrupts the metastable gas/liquid interface to wet the DF and thus opens the valve. By judicious choice of the radial position and geometry of the valve, the burst frequency can be tuned over a wide range of rotational speeds nearly 10 times greater than those attained by common capillary burst valves based on hydrophobic constrictions. The broad range of reproducible burst frequencies of the DF valves bears the potential for full integration and automation of comprehensive, multi-step biochemical assay protocols. In this report we demonstrate DF valving, discuss the biocompatibility of using the films, and show a potential sequential valving system including the on-demand release of on-board stored liquid reagents, fast centrifugal sedimentation and vigorous mixing thus providing a viable basis for use in lab-on-a-disc platforms for point-of-care diagnostics and other life science applications.
Publisher: Springer Science and Business Media LLC
Date: 17-02-2010
Publisher: Elsevier BV
Date: 08-2014
Publisher: Springer Science and Business Media LLC
Date: 04-11-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3MH00144J
Abstract: Ultra-large graphene oxide sheets exhibit unique viscoelastic properties, making them a new class of soft material. We provide fundamental insights enabling development of various fabrication techniques utilizing this 2D material.
Publisher: Informa UK Limited
Date: 10-03-2022
Publisher: International Society for Horticultural Science (ISHS)
Date: 08-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2LC40781G
Abstract: This work describes the first use of a wireless paired emitter detector diode device (PEDD) as an optical sensor for water quality monitoring in a lab-on-a-disc device. The microfluidic platform, based on an ionogel sensing area combined with a low-cost optical sensor, is applied for quantitative pH and qualitative turbidity monitoring of water s les at point-of-need. The autonomous capabilities of the PEDD system, combined with the portability and wireless communication of the full device, provide the flexibility needed for on-site water testing. Water s les from local fresh and brackish sources were successfully analysed using the device, showing very good correlation with standard bench-top systems.
Publisher: Informa UK Limited
Date: 02-02-2023
Publisher: Wiley
Date: 29-04-2014
DOI: 10.1002/POLB.23497
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA07109C
Abstract: Ionic-covalent entanglement hydrogels were fabricated by 3D-printing.
Location: Ireland
Location: Australia
No related grants have been discovered for Robert Gorkin.