ORCID Profile
0000-0003-4920-5472
Current Organisation
CSIRO
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Publisher: Wiley
Date: 29-06-2020
DOI: 10.1002/JBM.A.37024
Abstract: We have engineered biomaterials that display nanoclusters of ligands that bind both integrin and syndecan-4 cell receptors. These surfaces regulate cell behaviors under static conditions including adhesion, spreading, actin stress fiber formation, and migration. The syndecan-4 receptors are also critical mediators of cellular mechanotransduction. In this contribution we assess whether this novel class of materials can regulate the response of cells to applied mechanical stimulation, using the shear stress imparted by laminar fluid flow as a model stimulus. Specifically, we assess endothelial cell detachment due to flow, cell alignment due to flow, and cell adhesion from the flowing fluid. A high degree of cell retention was observed on surfaces containing integrin-binding ligands or a mixed population of integrin- and syndecan-binding ligands. However, the presence of both ligand types was necessary for the cells to align in the direction of flow. These results imply that integrin engagement is necessary for adhesion strength, but engagement of both receptor types aids in appropriate mechanotransduction. Additionally, it was found that surfaces functionalized with both ligand types were able to scavenge a larger number of cells from flow, and to do so at a faster rate, compared to surfaces functionalized with only integrin- or syndecan-binding ligands. These results show that interfaces functionalized with both integrin- and syndecan-binding ligands regulate a significant range of biophysical cell behaviors in response to shear stress.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TB01298E
Abstract: Blood contacting devices are commonly used in today's medical landscape.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.BIOMATERIALS.2018.10.002
Abstract: Biomaterials are a powerful platform for directing cellular behaviour. Herein, we employed a biomimetic strategy to synthesize a low-fouling polymer functionalized with nano-scale clusters of ligands that bind both integrin and syndecan-4 receptors, as both receptor types are critical in focal adhesion signalling and mechanotransduction. Our results demonstrate that the presence of both ligand types synergistically increases the adhesion of human umbilical vein endothelial cells (more than a two fold increase after 4 h) and increases the rate of surface endothelialization compared to surfaces functionalized with only one ligand type. Additionally, we observe that the mixed population of ligands regulates endothelial cell migration, likely due to improved focal adhesion formation as observed through confocal microscopy. Furthermore, we illustrate that only endothelial cells cultured on these mixed ligand surfaces exhibit the appropriate morphological changes - elongation and alignment in the direction of flow - when exposed to laminar shear flow, and neither of the in idual ligands alone is sufficient. These results illustrate that both receptor types must be engaged for optimum cell-material interactions and are mandatory for appropriate mechanotransduction. The results presented in this manuscript will be critical for the development of next generation biomedical devices and tissue engineering scaffolds.
Publisher: American Chemical Society (ACS)
Date: 16-11-2020
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.IJBIOMAC.2013.06.054
Abstract: Complex coacervation in exfoliated Laponite nanoplatelets and fish gelatin mixtures was studied as a function of four key parameters: pH, ionic strength, gelatin/Laponite weight ratio, and total weight. The aim was to understand how these parameters influence phase separation kinetics, composition, internal structure, and viscoelastic properties of coacervates. By careful experimental design and turbidity measurements, the optimum conditions for coacervation were obtained. Thermogravimetric analysis revealed an outstanding heat-resistance for gelatin/nanoclay coacervates. Finally, structure of the coacervate phase was characterized by oscillatory shear experiments. The storage modulus data was observed to follow a power-law behavior and it was confirmed that under the optimum conditions, the coacervate phase was dense and structured with a characteristic length scale (ξrheol) of ~8.25 nm. Regardless of the physicochemical condition at which complexation occurred, it was shown that the equilibrium structure of the coacervates is related to the kinetics of intermediate and late stages of phase separation as the new defined kinetics parameter K was observed to be inversely proportional to ξrheol that quantifies the compactness of the coacervate networks.
Publisher: American Chemical Society (ACS)
Date: 22-08-2017
DOI: 10.1021/ACS.BIOCONJCHEM.7B00360
Abstract: A dual-responsive, cell capture and release surface was prepared through the incorporation of phenylboronic acid (PBA) groups into an oxime-based polyethylene glycol (PEG) hydrogel. Owing to its PEG-like properties, the unfunctionalized hydrogel was nonfouling. The use of highly efficient oxime chemistry allows the incorporation of commercially available 3,5-diformylphenyl boronic acid into the hydrogel matrix. Thus, the surface properties of the hydrogel were modified to enable reversible cell capture and release. Boronic ester formation between PBA groups and cell surface carbohydrates enabled efficient cell capture at pH 6.8. An increase to pH 7.8 resulted in cell detachment. This capture-and-release procedure was performed on MCF-7 human breast cancer cells, NIH-3T3 fibroblast cells, and primary human umbilical vein endothelial cells (HUVECs) and could be cycled with negligible loss in activity. The facile preparation of PBA-functionalized surfaces presented here has applications in biomedical fields such as cell diagnostics and cell culture.
Publisher: Wiley
Date: 02-2019
Abstract: The use of ultrasound as an external stimulus for promoting polymerization reactions has received increasing attention in recent years. In this Review article, the fundamental processes that can lead to either the homolytic cleavage of polymer chains, or the sonolysis of solvent (or other) small molecules, under the application of ultrasound are described. These reactions promote the production of reactive radicals, which can be utilized in chain-growth radical polymerizations under the right conditions. A full historical overview of the development of ultrasound-assisted radical polymerization is provided, with special attention given to the recently described systems that are "controlled" by methods of reversible (radical) deactivation. Perspectives are shared on what challenges still remain in polymer sonochemistry, as well as new areas that are yet to be explored.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9CS00738E
Abstract: This review provides a comprehensive overview of the latest advances in the synthesis, architectural design and biomedical applications of polypeptides and their hybrids.
Publisher: American Chemical Society (ACS)
Date: 06-07-2022
Abstract: Biofunctionalization of silk biomaterial surfaces with extracellular matrix (ECM) molecules, cell binding peptides, or growth factors is important in a range of applications, including tissue engineering and development of implantable medical devices. Passive adsorption is the most common way to immobilize molecules of interest on preformed silk biomaterials but can lead to random molecular orientations and displacement from the surface, limiting their applications. Herein, we developed techniques for covalent immobilization of biomolecules using enzyme- or photoinitiated formation of dityrosine bonds between the molecule of interest and silk. Using recombinantly expressed domain V of the human basement membrane proteoglycan perlecan (rDV) as a model molecule, we demonstrated that rDV can be covalently immobilized via dityrosine cross-linking without the need to modify rDV or silk biomaterials. Dityrosine-based immobilization resulted in a different molecular orientation to passively absorbed rDV with less C- and N-terminal region exposure on the surface. Dityrosine-based immobilization supported functional rDV immobilization where immobilized rDV supported endothelial cell adhesion, spreading, migration, and proliferation. These results demonstrate the utility of dityrosine-based cross-linking in covalent immobilization of tyrosine-containing molecules on silk biomaterials in the absence of chemical modification, adding a simple and accessible technique to the silk biofunctionalization toolbox.
Publisher: Informa UK Limited
Date: 03-02-2020
Publisher: American Chemical Society (ACS)
Date: 13-05-2021
Publisher: Wiley
Date: 25-03-2018
Abstract: Material systems that exhibit tailored interactions with cells are a cornerstone of biomaterial and tissue engineering technologies. One method of achieving these tailored interactions is to biofunctionalize materials with peptide ligands that bind integrin receptors present on the cell surface. However, cell biology research has illustrated that both integrin binding and integrin clustering are required to achieve a full adhesion response. This biophysical knowledge has motivated researchers to develop material systems biofunctionalized with nanoscale clusters of ligands that promote both integrin occupancy and clustering of the receptors. These materials have improved a wide variety of biological interactions in vitro including cell adhesion, proliferation, migration speed, gene expression, and stem cell differentiation and improved in vivo outcomes including increased angiogenesis, tissue healing, and biomedical device integration. This review first introduces the techniques that enable the fabrication of these nanopatterned materials, describes the improved biological effects that have been achieved, and lastly discusses the current limitations of the technology and where future advances may occur. Although this technology is still in its nascency, it will undoubtedly play an important role in the future development of biomaterials and tissue engineering scaffolds for both in vitro and in vivo applications.
Publisher: American Chemical Society (ACS)
Date: 08-08-2016
DOI: 10.1021/ACS.BIOMAC.6B00817
Abstract: Synthetic polypeptides are a class of bioinspired polymers with well demonstrated biocompatibility, enzyme biodegradability, and cell adhesive properties, making them promising materials for the preparation of macroporous hydrogels as 3D cellular scaffolds. Three-dimensional macroporous hydrogels composed entirely of biocompatible and enzyme biodegradable synthetic polypeptides have thus been prepared. Under cryoconditions, macroporous hydrogels in the form of macroporous cryogels were prepared using a single copolymer component through direct EDC/sulfo-NHS zero-length cross-linking between poly(l-glutamic acid) (PLG) and poly(l-lysine) (PLL) residues on a PLG-r-PLL random copolypeptide chain. The resulting macroporous cryogels were found to contain large interconnected pores (≥100 μm) highly suitable for tissue engineering applications. Tuning the relative ratios of the amino acid components could result in cryogels with very different pore structures, swelling, and mechanical properties, suitable for developing gels for a range of possible soft tissue engineering applications. These cryogels were shown to be enzymatically biodegradable and demonstrated excellent biocompatibility, cell attachment and cell proliferation profiles with mammalian fibroblast (NIH-3T3) cells, demonstrating the appeal of these novel cryogels as highly suitable cellular scaffolds.
Publisher: American Chemical Society (ACS)
Date: 20-09-2019
Publisher: Wiley
Date: 29-10-2021
Publisher: American Chemical Society (ACS)
Date: 20-09-2017
Abstract: A novel reduced iron metal-organic framework nanoparticle with cytotoxicity specific to cancer cells is presented. This nanoparticle was prepared via a hydrothermal method, reduced using hydroquinone, and finally conjugated with folic acid (namely, rMOF-FA). The synthesized nanoparticle shows the controlled release of iron in an acidic ex-vivo environment. Iron present on the rMOF-FA and released into solution can react with high levels of hydrogen peroxide found specifically in cancer cells to increase the hydroxyl radical concentration. The hydroxyl radicals oxidize proteins, lipids, and/or DNA within the biological system to decrease cell viability. In vitro experiments demonstrate that this novel nanoparticle is cytotoxic to cancer cells (HeLa) through generation of OH
Location: Iran (Islamic Republic of)
No related grants have been discovered for Fatemeh Karimi.