ORCID Profile
0000-0002-5923-4157
Current Organisation
University of New South Wales
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Microtechnology | Industrial Biotechnology | Bioprocessing, Bioproduction and Bioproducts | Manufacturing Engineering | Medical Devices | Membrane And Separation Technologies | Heat And Mass Transfer Operations | Biomedical Engineering Not Elsewhere Classified | Interdisciplinary Engineering | Biological Physics
ANZSRC Socio-Economic Objective (SEO)
Medical Instruments | Conservation and efficiency | Livestock Raising not elsewhere classified | Renewable energy | Expanding Knowledge in Engineering | Human Pharmaceutical Products not elsewhere classified | Veterinary Pharmaceutical Products not elsewhere classified | Manufacturing not elsewhere classified | Organs, diseases and abnormal conditions not elsewhere classified |
Related Links
Publications
Application of microfluidics to study stem cell dynamics
Publisher: Humana Press
Date: 2013
PDGFRα signaling in cardiac fibroblasts modulates quiescence, metabolism and self-renewal, and promotes anatomical and functional repair
Publisher: Cold Spring Harbor Laboratory
Date: 28-11-2017
DOI: 10.1101/225979
Abstract: The interstitial and perivascular spaces of the mammalian heart contain a highly interactive tissue community essential for cardiac homeostasis, repair and regeneration. Mesenchymal cells (fibroblasts) are one of the most abundant cell types, playing key roles as sentinels, tissue architects, paracrine signaling hubs and lineage precursors, and are linked to heart disease through their roles in inflammation and fibrosis. Platelet-derived growth factors (PDGFs) are secreted by several cell types involved in cardiac injury and repair, and are recognized mitogens for cardiac fibroblasts and mesenchymal stem cells. However, their roles are complex and investigations of their impact on heart repair have produced contrasting outcomes, leaving therapeutic potential uncertain. Here, we use new approaches and tools, including single cell RNA sequencing, to explore cardiac fibroblast heterogeneity and how PDGF receptor α (PDGFRα) signaling impacts fibroblasts during heart repair. Short-term systemic delivery of PDGF-AB to mice from the time of myocardial infarction (MI) led to enhanced anatomical and functional recovery. Underpinning these benefits was a priming effect, in which PDGF-AB accelerated exit of fibroblasts from quiescence and induced a higher translational biosynthetic capacity in both fibroblasts and macrophages without triggering fibrosis. Our study highlights the significant biosynthetic heterogeneity and plasticity in cardiac fibroblast populations, and suggests a rationale for a novel therapeutic approach to cardiac injury involving controlled stimulation of fibroblast activation.
Microfluidic Obstacle Arrays Induce Large Reversible Shape Change in Red Blood Cells
Publisher: MDPI AG
Date: 30-06-2021
DOI: 10.3390/MI12070783
Abstract: Red blood cell (RBC) shape change under static and dynamic shear stress has been a source of interest for at least 50 years. High-speed time-lapse microscopy was used to observe the rate of deformation and relaxation when RBCs are subjected to periodic shear stress and deformation forces as they pass through an obstacle. We show that red blood cells are reversibly deformed and take on characteristic shapes not previously seen in physiological buffers when the maximum shear stress was between 2.2 and 25 Pa (strain rate 2200 to 25,000 s−1). We quantify the rates of RBC deformation and recovery using Kaplan–Meier survival analysis. The time to deformation decreased from 320 to 23 milliseconds with increasing flow rates, but the distance traveled before deformation changed little. Shape recovery, a measure of degree of deformation, takes tens of milliseconds at the lowest flow rates and reached saturation at 2.4 s at a shear stress of 11.2 Pa indicating a maximum degree of deformation was reached. The rates and types of deformation have relevance in red blood cell disorders and in blood cell behavior in microfluidic devices.
Controlling Endosomal Escape Using pH-Responsive Nanoparticles with Tunable Disassembly
Publisher: American Chemical Society (ACS)
Date: 05-06-2018
An experimental model of affinity cell separation
Publisher: Wiley
Date: 05-1994
Abstract: Cell affinity separations are based on the selective attachment of cell phenotype using antibody or lectins specific for cell surface markers. The major physicochemical factors which influence ligand-mediated cell adhesion dynamics and the efficiency of cell affinity separation have been examined. Uniform cell detachment forces were generated with a parallel-plate flow cell (plate separation 100 microns, surface area 3 cm2). Hydrodynamic shear stress was used to measure cell adhesion strength and to separate cells on the basis of surface affinity. Human cell lines grown in tissue culture were separated on a flat derivatised glass immunoadsorbent which formed the floor of the flow chamber. Flow-cell residence time, detachment shear stress, temperature, and ligand density were shown to influence cell attachment probability. An understanding of the physical basis of ligand-mediated cell adhesion provided a rationale for optimisation of affinity cell separation. At room temperature attachment of positive cells was rapid (< 2 min) and adhesion strength was directly related to immunoadsorbent ligand density. Purity and recovery of enriched fractions were dependent on the separation shear stress and could be optimised using this parameter. Enrichment factors were greater than 100-fold, with at least 90% of positive cells recovered in enriched fractions. Enrichment purity and yields did not decline at higher loading densities (10(5) cells/cm2). Selective immunoadsorbent surface chemistry is a prerequisite for efficient affinity cell separation. Purity and recovery may be optimised by fractionating enriched and depleted cell populations with uniform fluid shear stress.
Characterization of cytokine interactions by flow cytometry and factorial analysis
Publisher: Wiley
Date: 2001
DOI: 10.1002/1097-0320(20010101)43:1<69::AID-CYTO1020>3.0.CO;2-5
Design of microdevices for long-term live cell imaging
Publisher: IOP Publishing
Date: 29-05-2012
Hollow-fibre affinity cell separation
Publisher: Springer Berlin Heidelberg
Date: 2007
DOI: 10.1007/10_2006_041
Abstract: The developing fields of cell and tissue engineering will require cost-effective technologies for delivery of cells to patients. Hollow-fibre affinity cell separation is a monoclonal antibody-based cell separation process whereby monoclonal antibody (ligand) is immobilised onto a stationary substrate, the luminal surface of a parallel array of hollow fibres. Deposited cells are fractionated on the basis of adhesion strength using hollow fibre geometry that generates a well-defined shear stress for cell recovery. In this chapter we present the biophysical basis for the process of ligand-mediated cell adhesion and relate this to the performance of affinity cell separation. We also discuss the hydrodynamics of hollow fibre arrays and the various approaches for modifying polymer substrates with protein ligands. One of the major limiting factors for large-scale epitope selective cell separation will be the prohibitive cost of these affinity processes. Hollow fibre systems offer the promise of providing flexibility and scalability for many of these applications.
Mesenchymal stem cells in tissue engineering
Publisher: Wiley
Date: 20-02-2008
DOI: 10.1002/JCTB.1901
Engineered proteins containing the cohesin and dockerin domains from Clostridium thermocellum provides a reversible, high affinity interaction for biotechnology applications
Publisher: Elsevier BV
Date: 2006
DOI: 10.1016/J.JBIOTEC.2005.07.005
Abstract: The cohesin-dockerin interaction, which is responsible for the formation of the cellulosome complex of cellulolytic bacteria, is a calcium-dependent, high affinity interaction. In this study, the cohesin (Cip7) and dockerin (Doc) domains of Clostridium thermocellum were fused to the cellulose-binding domain (CBD) of C. cellulovorans and the antibody-binding domain, protein LG, respectively, to form CBD-Cip7 and LG-Doc. Immobilised CBD-Cip7 was able to bind LG-Doc and subsequently antibody as determined using surface plasmon resonance. Binding was reversed by the removal of Ca2+ with EDTA. The dockerin containing fusion protein was affinity purified using an immobilised cohesin domain. Elution of the LG-Doc from the cohesin column was with EDTA. This affinity chromatography was repeated using an LG-dockerin column for the purification of cohesin fusion protein. The fusion proteins created in this report have shown that the properties of the cohesin and dockerin domains can be transferred to other protein domains and that the interaction between the cohesin and dockerin is specific, Ca2+ -dependent and reversible. We have shown that the cohesin-dockerin interaction has several properties making it suitable for use in recombinant fusion protein production and purification.
Hollow-fibre affinity cell separation system for CD34+ cell enrichment
Publisher: Wiley
Date: 08-1996
DOI: 10.1002/(SICI)1097-0320(19960801)24:4<340::AID-CYTO5>3.0.CO;2-J
Abstract: Forty years into the HIV pandemic, approximately 50% of infected in iduals still suffer from a constellation of neurological disorders collectively known as 'neuroHIV.' Although combination antiretroviral therapy (cART) has been a tremendous success, in its present form, it cannot eradicate HIV. Reservoirs of virus reside within the central nervous system, serving as sources of HIV virotoxins that damage mitochondria and promote neurotoxicity. Although understudied, there is evidence that HIV or the HIV regulatory protein, trans-activator of transcription (Tat), can dysregulate neurosteroid formation potentially contributing to endocrine dysfunction. People living with HIV commonly suffer from endocrine disorders, including hypercortisolemia accompanied by paradoxical adrenal insufficiency upon stress. Age-related comorbidities often onset sooner and with greater magnitude among people living with HIV and are commonly accompanied by hypogonadism. In the post-cART era, these derangements of the hypothalamic-pituitary-adrenal and -gonadal axes are secondary (i.e., relegated to the brain) and indicative of neuroendocrine dysfunction. We review the clinical and preclinical evidence for neuroendocrine dysfunction in HIV, the capacity for hormone therapeutics to play an ameliorative role and the future steroid-based therapeutics that may have efficacy as novel adjunctives to cART.
Chimeric protein for selective cell attachment onto cellulosic substrates
Publisher: Oxford University Press (OUP)
Date: 2007
Abstract: We have developed a fusion protein (CBD-LG) incorporating a cellulose-binding domain and an antibody binding domain, protein LG, to provide an adaptor molecule for cell separation with regenerated cellulose hollow fiber arrays. A single hollow fiber cell adhesion assay utilizing a CD34+ cell line, KG1a, was used to investigate whether ligand affinity interactions were strong enough for cell attachment and separation. CBD-LG efficiently captured CD34+ cells labeled with the mouse IgG2a monoclonal antibody MHCD3400. However, it was not possible to bind CD34+ cells labeled with an IgG1 antibody (HPCA-2). The low affinity of HPCA-2 for LG was overcome by secondary antibodies: KG1a cells that were dual labeled with HPCA-2 followed by rat anti-mouse IgG1 adhered inside hollow fibers coated with CBD-LG. Alternatively, immobilized rabbit polyclonal anti-mouse IgG1 captured cells labeled with HPCA-2. The development of an adaptor molecule to display recombinant domains at the surface of hollow fibers will be an effective tool to investigate cellular ligand-receptor interactions, a necessary step in the development of hollow fiber bioreactors for manufacture of human cellular products.
Analysis of growth kinetics by division tracking
Publisher: Wiley
Date: 12-1999
DOI: 10.1046/J.1440-1711.1999.00869.X
Abstract: Cell ision tracking using fluorescent dyes, such as carboxyfluorescein diacetate succinimidyl ester, provides a unique opportunity for analysis of cell growth kinetics. The present review article presents new methods for enhancing resolution of ision tracking data as well as derivation of quantities that characterize growth from time-series data. These include the average time between successive isions, the proportion of cells that survive and the proliferation per ision. The physical significance of these measured quantities is interpreted by formulation of a two-compartment model of cell cycle transit characterized by stochastic and deterministic cell residence times, respectively. The model confirmed that survival is directly related to the proportion of cells that enter the next cell generation. The proportion of time that cells reside in the stochastic compartment is directly related to the proliferation per generation. This form of analysis provides a starting point for more sophisticated physical and biochemical models of cell cycle regulation.
Microwell perfusion array for high-throughput, long-term imaging of clonal growth
Publisher: AIP Publishing
Date: 12-2011
DOI: 10.1063/1.3669371
Abstract: Continuous cell tracking by time-lapse microscopy has led to detailed study of cell differentiation pathways using single cell fate maps. There are a multitude of cell fate outcomes, so hundreds of clonal ision histories are required to measure these stochastic branching processes. This study examines the principle of condensing cell imaging information into a relatively small region to maximize live cell imaging throughput. High throughput clonal analysis of non-adherent cells by continuous live cell tracking was possible using a microwell perfusion array with an internal volume of 16 μl and 600 microwells at the base. This study includes examination of biocompatibility of buffer systems, connecting tubing, cell culture substrates, and media degradation. An intermittent perfusion protocol was selected for long-term time-lapse imaging of KG1a cells in the microwell array 1500 clones were simultaneously cultured and scanned every 3 min at 100 × magnifications for 6 days. The advantages of perfusion microwell culture are continuous long-term cell tracking, higher cell imaging throughput, and greater control over cell microenvironment. Microwell devices facilitate high throughput analysis of cell lineage development and measurement of the probability distribution for cell life events such as mitosis.
Interaction of endothelial cells with plasma-polymer modified surfaces
Publisher: Elsevier BV
Date: 03-2020
Prolonged ex vivo culture of cord blood CD34 + cells facilitates myeloid and megakaryocytic engraftment in the non-obese diabetic severe combined immunodeficient mouse model
Publisher: Wiley
Date: 08-2001
DOI: 10.1046/J.1365-2141.2001.02942.X
Abstract: A clinical goal for ex vivo expansion of cord blood (CB) CD34(+) cells is to shorten the period of neutropenia and thrombocytopenia following myeloablative therapy and transplantation. Prolongation of cytokine expansion leads to the production of greater numbers of cells, and should have an impact on neutrophil and platelet recovery. Furthermore, expansion of CD34(+) cells should support the continued production of neutrophils and platelets in the 6-week period following transplantation. We tested these hypotheses by characterization of the kinetics (human CD45(+) cells in the blood) and phenotype (CD45, CD34, CD61, CD33, CD19 and CD3) of human engraftment in the non-obese diabetic severe combined immunodeficient mouse (NOD-SCID) following 7 or 14 d of ex vivo expansion of CB CD34(+) cells. Mice transplanted with 14 d cells showed greater percentages of human CD45(+) cells in the blood, bone marrow and spleen than mice transplanted with unexpanded cells or 7 d cells. Prolonging cytokine exposure of CD34(+) cells and transplantation with increasing numbers of input cells facilitated the production of absolute numbers of CD34(+), CD33(+), CD61(+) and CD19(+) cells in vivo. Furthermore, analysis of SCID engrafting potential showed that prolongation of culture duration facilitates in vivo expansion of CD45(+), CD34(+) and CD19(+) cells after transplantation. It is anticipated that prolonged (2 weeks) ex vivo culture of CB will have a beneficial clinical effect.
Treatment-induced cell cycle kinetics dictate tumor response to chemotherapy
Publisher: Impact Journals, LLC
Date: 07-02-2015
Abstract: Chemotherapy fails to provide durable cure for the majority of cancer patients. To identify mechanisms associated with chemotherapy resistance, we identified genes differentially expressed before and after chemotherapeutic treatment of breast cancer patients. Treatment response resulted in either increased or decreased cell cycle gene expression. Tumors in which cell cycle gene expression was increased by chemotherapy were likely to be chemotherapy sensitive, whereas tumors in which cell cycle gene transcripts were decreased by chemotherapy were resistant to these agents. A gene expression signature that predicted these changes proved to be a robust and novel index that predicted the response of patients with breast, ovarian, and colon tumors to chemotherapy. Investigations in tumor cell lines supported these findings, and linked treatment induced cell cycle changes with p53 signaling and G1/G0 arrest. Hence, chemotherapy resistance, which can be predicted based on dynamics in cell cycle gene expression, is associated with TP53 integrity.
A rapid co-culture stamping device for studying intercellular communication
Publisher: Springer Science and Business Media LLC
Date: 18-10-2016
DOI: 10.1038/SREP35618
Abstract: Regulation of tissue development and repair depends on communication between neighbouring cells. Recent advances in cell micro-contact printing and microfluidics have facilitated the in-vitro study of homotypic and heterotypic cell-cell interaction. Nonetheless, these techniques are still complicated to perform and as a result, are seldom used by biologists. We report here development of a temporarily sealed microfluidic st ing device which utilizes a novel valve design for patterning two adherent cell lines with well-defined interlacing configurations to study cell-cell interactions. We demonstrate post-st ing cell viability of %, the st ing of multiple adherent cell types, and the ability to control the seeded cell density. We also show viability, proliferation and migration of cultured cells, enabling analysis of co-culture boundary conditions on cell fate. We also developed an in-vitro model of endothelial and cardiac stem cell interactions, which are thought to regulate coronary repair after myocardial injury. The st is fabricated using microfabrication techniques, is operated with a lab pipettor and uses very low reagent volumes of 20 μl with cell injection efficiency of %. This easy-to-use device provides a general strategy for micro-patterning of multiple cell types and will be important for studying cell-cell interactions in a multitude of applications.
Computational Tools for Quantifying Concordance in Single-Cell Fate
Publisher: Springer New York
Date: 2019
DOI: 10.1007/978-1-4939-9224-9_6
Abstract: Cells are dynamic biological systems that interact with each other and their surrounding environment. Understanding how cell extrinsic and intrinsic factors control cell fate is fundamental to many biological experiments. However, due to transcriptional heterogeneity or microenvironmental fluctuations, cell fates appear to be random. In idual cells within well-defined subpopulations vary with respect to their proliferative potential, survival, and lineage potency. Therefore, methods to quantify fate outcomes for heterogeneous populations that consider both the stochastic and deterministic features of single-cell dynamics are required to develop accurate models of cell growth and differentiation. To study random versus deterministic cell behavior, one requires a probabilistic modelling approach to estimate cumulative incidence functions relating the probability of a cell's fate to its lifetime and to model the deterministic effect of cell environment and inheritance, i.e., nature versus nurture. We have applied competing risks statistics, a branch of survival statistics, to quantify cell fate concordance from cell lifetime data. Competing risks modelling of cell fate concordance provides an unbiased, robust statistical modelling approach to model cell growth and differentiation by estimating the effect of cell extrinsic and heritable factors on the cause-specific cumulative incidence function.
Scaling deterministic lateral displacement arrays for high throughput and dilution-free enrichment of leukocytes
Publisher: IOP Publishing
Date: 28-04-2011
High-resolution cell division tracking demonstrates the Flt3-ligand- dependence of human marrow CD34+CD38- cell production in vitro
Publisher: Wiley
Date: 09-1997
DOI: 10.1046/J.1365-2141.1997.2823097.X
Abstract: Investigation of primitive human haemopoietic cell behaviour requires methodologies for monitoring asynchronously activated cells over several generations. We describe a high-resolution procedure for tracking 5- (and 6-) carboxyfluorescein diacetate succinimidyl ester (CFSE)- labelled human haemopoietic cells through six cell cycles based on the precise halving of their CFSE-fluorescence at each mitosis. Using this approach in combination with DNA or surface antigen staining, we show that the addition of Flt3-ligand (FL) to a cytokine cocktail consisting of Steel factor, IL-3, IL-6 and G-CSF increased the proportion of CD34+ (CD45RA/CD71)-, but not CD34+(CD45RA/CD71)+, human marrow cells initially recruited into ision in vitro, shortened the overall cycle time of their progeny, and enhanced the production of a derivative CD34+CD38- population through several (up to four) cell generations. These studies also showed that during the first 4d there was no detectable apoptosis among the progeny of the CD34+(CD45RA/CD71)- cells generated in the presence of this four-cytokine cocktail, regardless of the presence of FL. The availability of a technique for monitoring changes in the properties of in idual cells as a function of their mitotic history and under conditions where they are asynchronously recruited to ide provides a new and powerful approach for studies of the regulation of primitive human haemopoietic cell proliferation and differentiation.
Design of bioreactors for mesenchymal stem cell tissue engineering
Publisher: Wiley
Date: 18-02-2008
DOI: 10.1002/JCTB.1918
Part 2: Making the “unproven” “proven”
Publisher: Elsevier BV
Date: 2016
Scrutinizing calcium flux oscillations in T lymphocytes to deduce the strength of stimulus
Publisher: Springer Science and Business Media LLC
Date: 14-01-2015
DOI: 10.1038/SREP07760
TrackPad: Software for semi-automated single-cell tracking and lineage annotation
Publisher: Elsevier BV
Date: 2020
Ex vivo expansion of hematopoietic stem cells to improve engraftment in stem cell transplantation
Publisher: Springer New York
Date: 05-11-2016
DOI: 10.1007/978-1-4939-6603-5_19
Abstract: The efficient use of hematopoietic stem cells (HSC) for transplantation is often limited by the relatively low numbers of HSC collected. The ex vivo expansion of HSC for clinical use is a potentially valuable and safe approach to increase HSC numbers thereby increasing engraftment and reducing the risk of morbidity from infection. Here, we describe a protocol for the robust ex vivo expansion of human CD34(+) HSC isolated from umbilical cord blood. The protocol described can efficiently generate large numbers of HSC. We also describe a flow cytometry-based method using high-resolution ision tracking to characterize the kinetics of HSC growth and differentiation. Utilizing the guidelines discussed, it is possible for investigators to use this protocol as presented or to modify it for their specific needs.
FACS Enrichment of Total Interstitial Cells and Fibroblasts from Adult Mouse Ventricles
Publisher: Bio-Protocol, LLC
Date: 2021
Droplet-based single cell RNAseq tools: a practical guide
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8LC01239C
Abstract: A step-by-step guide for droplet-based single cell RNAseq experiments, practical considerations and technical notes.
Mimicry of embryonic circulation enhances the hoxa hemogenic niche and human blood development
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.CELREP.2022.111339
Abstract: Precursors of the adult hematopoietic system arise from the aorta-gonad-mesonephros (AGM) region shortly after the embryonic circulation is established. Here, we develop a microfluidic culture system to mimic the primitive embryonic circulation and address the hypothesis that circulatory flow and shear stress enhance embryonic blood development. Embryonic (HOXA
A novel flash detection algorithm for single molecule counting with TIRF microscopy
Publisher: IEEE
Date: 04-2013
Quantifying intrinsic and extrinsic control of single-cell fates in cancer and stem/progenitor cell pedigrees with competing risks analysis
Publisher: Springer Science and Business Media LLC
Date: 06-2016
DOI: 10.1038/SREP27100
Abstract: The molecular control of cell fate and behaviour is a central theme in biology. Inherent heterogeneity within cell populations requires that control of cell fate is studied at the single-cell level. Time-lapse imaging and single-cell tracking are powerful technologies for acquiring cell lifetime data, allowing quantification of how cell-intrinsic and extrinsic factors control single-cell fates over time. However, cell lifetime data contain complex features. Competing cell fates, censoring, and the possible inter-dependence of competing fates, currently present challenges to modelling cell lifetime data. Thus far such features are largely ignored, resulting in loss of data and introducing a source of bias. Here we show that competing risks and concordance statistics, previously applied to clinical data and the study of genetic influences on life events in twins, respectively, can be used to quantify intrinsic and extrinsic control of single-cell fates. Using these statistics we demonstrate that 1) breast cancer cell fate after chemotherapy is dependent on p53 genotype 2) granulocyte macrophage progenitors and their differentiated progeny have concordant fates and 3) cytokines promote self-renewal of cardiac mesenchymal stem cells by symmetric isions. Therefore, competing risks and concordance statistics provide a robust and unbiased approach for evaluating hypotheses at the single-cell level.
Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR00289E
Abstract: A biocompatible Fmoc-hexapeptide which forms hydrogels at physiological pH upon heating is reported.
High-fidelity replication of thermoplastic microneedles with open microfluidic channels
Publisher: Springer Science and Business Media LLC
Date: 09-10-2017
DOI: 10.1038/MICRONANO.2017.34
Abstract: Development of microneedles for unskilled and painless collection of blood or drug delivery addresses the quality of healthcare through early intervention at point-of-care. Microneedles with submicron to millimeter features have been fabricated from materials such as metals, silicon, and polymers by subtractive machining or etching. However, to date, large-scale manufacture of hollow microneedles has been limited by the cost and complexity of microfabrication techniques. This paper reports a novel manufacturing method that may overcome the complexity of hollow microneedle fabrication. Prototype microneedles with open microfluidic channels are fabricated by laser stereolithography. Thermoplastic replicas are manufactured from these templates by soft-embossing with high fidelity at submicron resolution. The manufacturing advantages are (a) direct printing from computer-aided design (CAD) drawing without the constraints imposed by subtractive machining or etching processes, (b) high-fidelity replication of prototype geometries with multiple reuses of elastomeric molds, (c) shorter manufacturing time compared to three-dimensional stereolithography, and (d) integration of microneedles with open-channel microfluidics. Future work will address development of open-channel microfluidics for drug delivery, fluid s ling and analysis.
Bio-synthetic encapsulation systems for organ engineering: Focus on diabetes
Publisher: Springer Berlin Heidelberg
Date: 21-05-2011
Susceptibility of Cell Populations to Transduction by Retroviral Vectors
Publisher: American Society for Microbiology
Date: 15-05-2004
DOI: 10.1128/JVI.78.10.5097-5102.2004
Abstract: Retroviral transduction efficiency is related to the multiplicity of infection and the physiological state of the target cells. It is generally not known what proportion of a cell population is susceptible to transduction. We used coinfection with two retroviral vectors containing the marker genes for green fluorescent protein and the truncated human nerve growth factor receptor. In the CD34 + cell line TF-1 or human primary CD34 + hematopoietic progenitor cells, it was found that cells transduced with one vector had a better than random chance of transduction by the other vector. A probability model was developed to estimate target cell susceptibility susceptibility was calculated as the product of the proportions of transgene-positive cells ided by the proportion of double-positive cells. By using this relationship, it was found that susceptibility was related to the target cell type and culture conditions but not the retroviral titer or the retroviral packaging envelope protein used in this study. Cotransduction with two vectors is a relatively simple procedure that provides a means to assess the maximum transduction level possible in a given cell population.
Donor T cells for CAR T cell therapy
Publisher: Springer Science and Business Media LLC
Date: 04-2022
DOI: 10.1186/S40364-022-00359-3
Abstract: Adoptive cell therapy using patient-derived chimeric receptor antigen (CAR) T cells redirected against tumor cells has shown remarkable success in treating hematologic cancers. However, wider accessibility of cellular therapies for all patients is needed. Manufacture of patient-derived CAR T cells is limited by prolonged lymphopenia in heavily pre-treated patients and risk of contamination with tumor cells when isolating T cells from patient blood rich in malignant blasts. Donor T cells provide a good source of immune cells for adoptive immunotherapy and can be used to generate universal off-the-shelf CAR T cells that are readily available for administration into patients as required. Genome editing tools such as TALENs and CRISPR-Cas9 and non-gene editing methods such as short hairpin RNA and blockade of protein expression are currently used to enhance CAR T cell safety and efficacy by abrogating non-specific toxicity in the form of graft versus host disease (GVHD) and preventing CAR T cell rejection by the host.
The correlations between structure, rheology, and cell growth in peptide-based multicomponent hydrogels
Publisher: Springer Science and Business Media LLC
Date: 05-2020
A sorry tale of unnecessary secrecy about medicine safety
Publisher: Wiley
Date: 10-2021
DOI: 10.1111/IMJ.15513
Cardiac-like flow generator for long-term imaging of endothelial cell responses to circulatory pulsatile flow at microscale
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3LC50123J
Abstract: In vitro models of circulatory hemodynamics are required to mimic the microcirculation for study of endothelial cell responses to pulsatile shear stress by live cell imaging. This study reports the design, fabrication and characterisation of a microfluidic device that generates cardiac-like flow in a continuous culture system with a circulatory volume of only 2-3 μL. The device mimics a single chamber heart, with the following cardiac phases: (1) closure of the ventricle inlet valve, (2) contraction of the ventricle (systole) followed by opening of the outlet valve and (3) relaxation of the ventricle (diastole) with opening of the inlet valve whilst the outlet valve remains closed. Periodic valve states and ventricular contractions were actuated by microprocessor controlled pneumatics. The time-dependent velocity-field was characterised by micro-particle image velocimetry (μ-PIV). μ-PIV observations were used to help tune electronic timing of valve states and ventricular contractions for synthesis of an arterial pulse waveform to study the effect of pulsatile shear stress on bovine artery endothelial cells (BAECs). BAECs elongated and aligned with the direction of shear stress after 48 h of exposure to a pulsatile waveform with a maximum shear stress of 0.42 Pa. The threshold for BAECs alignment and elongation under steady (non-pulsatile) flow reported by Kadohama et al. (2006) is 0.7-1.4 Pa. These cells respond to transient shear stress because the time average shear stress of the pulse waveform to generate this morphological response was only 0.09 Pa, well below the steady flow threshold. The microfluidic pulse generator can simulate circulatory hemodynamics for live cell imaging of shear-induced signalling pathways.
Formation of an adherent hematopoietic expansion culture using fucoidan
Publisher: Springer Science and Business Media LLC
Date: 17-02-2011
DOI: 10.1007/S00277-011-1185-4
Abstract: Expansion of transplantable cord blood (CB) progenitors using a stroma requires provision of an exogenous cell source because of the low frequency of stromal precursor cells in CB. A simpler approach from a clinical regulatory perspective would be to provide synthetic extracellular matrix. The aim of this study was to characterize the effect on hematopoietic cell culture of fucoidan. The modulation of cytokine-driven hematopoietic cell expansion by fucoidan was investigated using two-level fractional and full factorial experimental designs. Mobilized peripheral blood (PB) CD34(+) cells were grown over 10 days in various combinations of FL, SCF, TPO, G-CSF, and SDF-1. Cultures were analyzed by immunophenotype. The effect of fucoidan on the isional recruitment of CD34(+) cells was studied by CFDA-SE ision tracking. Fucoidan was adsorbed by polystyrene to tissue culture plates and promoted formation of an adherent hematopoietic culture. Factorial design experiments with mobilized PB-CD34(+) cells showed that fucoidan reduced the production of CD34(+) cells and CD34(+)CXCR4(+) ratio but did not affect the production of monocytic, granulocytic, or megakaryocytic cells. The inhibitory effect of fucoidan on expansion of CB-CD34(+) cells was greater than mobilized PB. Division tracking analysis showed that CD34(+) cell generation times were lengthened by fucoidan. Fucoidan binds growth factors via their heparin-binding domain. The formation of an adherent hematopoietic culture system by fucoidan is most likely mediated by the binding of L-selectin and integrin-αMβ2 on myeloids. Fucoidan deserves further investigation as glycan scaffold that is suitable for immobilization of other matrix molecules thought to comprise blood stem cell niche.
Molecular engineering of the cellulosome complex for affinity and bioenergy applications
Publisher: Springer Science and Business Media LLC
Date: 31-12-2009
DOI: 10.1007/S10529-008-9899-7
Abstract: The cellulosome complex has evolved to degrade plant cell walls and, as such, combines tenacious binding to cellulose with erse catalytic activities against amorphous and crystalline cellulose. Cellulolytic microorganisms provide an extensive selection of domains those with affinity for cellulose, cohesins and their dockerin binding partners that define cellulosome stoichiometry and architecture, and a range of catalytic activities against carbohydrates. These robust domains provide the building blocks for molecular design. This review examines how protein modules derived from the cellulosome have been incorporated into chimaeric proteins to provide biosynthetic tools for research and industry. These applications include affinity tags for protein purification, and non-chemical methods for immobilisation and presentation of recombinant protein domains on cellulosic substrates. Cellulosomal architecture provides a paradigm for design of enzymatic complexes that synergistically combine multiple catalytic subunits to achieve higher specific activity than would be obtained using free enzymes. Multimeric enzymatic complexes may have industrial applications of relevance for an emerging carbon economy. Biocatalysis will lead to more efficient utilisation of renewable carbon-fixing energy sources with the added benefits of reducing chemical waste streams and reliance on petroleum.
Prior cryopreservation of ex vivo-expanded cord blood cells is not detrimental to engraftment as measured in the NOD-SCID mouse model
Publisher: Mary Ann Liebert Inc
Date: 02-2001
DOI: 10.1089/152581601750098435
Abstract: Cytokine-mediated expansion has been proposed and successfully used to facilitate engraftment post transplantation. This study examined whether cryopreservation following expansion has a detrimental effect on the ability of cells to engraft, using the NOD-SCID mouse model. Cord blood (CB) CD34(+) cells were incubated for 7 days with stem cell factor (SCF), flt-3 ligand (FL), and megakaryocyte growth and development factor (MGDF). Expanded CD34(+) cells were transplanted into NOD-SCID mice either fresh or following cryopreservation and thawing. After thawing, recovery of nucleated cells was 94%, of CD34 cells was 63%, and of day-14 progenitors was 17%. The loss of day-14 progenitor cells among the thawed expanded cells did not influence the kinetics of human engraftment in the mouse. Bone marrow (BM) of mice transplanted with thawed expanded CD34(+) cells (14 +/- 3.9%) showed significantly higher levels of human engraftment than mice transplanted with fresh expanded CD34(+) cells (1.5 +/- 0.5%, p = 0.0064). Thawed expanded CD34(+) cells had significantly higher SCID Engrafting Potential (SEP) than freshly expanded CD34(+) cells (p < 0.001). Results suggest that prior cryopreservation does not prevent expanded cells engrafting in NOD-SCID mice.
Biological performance of a novel synthetic furanone-based antimicrobial
Publisher: Elsevier BV
Date: 09-2004
Analysis of cell differentiation by division tracking cytometry
Publisher: Wiley
Date: 25-07-2007
DOI: 10.1002/CYTO.A.20437
Abstract: We propose a quantitative method to characterize growth and differentiation dynamics of multipotent cells from time series carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE) ision tracking data. The dynamics of cell proliferation and differentiation was measured by combining (CFDA-SE) ision tracking with phenotypic analysis. We define ision tracking population statistics such as precursor cell frequency, generation time and renewal rate that characterize growth of various phenotypes in a heterogeneous culture system. This method is illustrated by study of the isional recruitment of cord blood CD34(+) cells by hematopoietic growth factors. The technical issue of assigning the correct generation number to cells was addressed by employing high-resolution ision tracking methodology and daily histogram analysis. We also quantified ision-tracking artifacts such as CFDA-SE degeneration and cellular auto-fluorescence. Mitotic activation of cord blood CD34(+) cells by cytokines commenced after 2 days of cytokine stimulation. Mean generation number increased linearly thereafter, and it was conclusively shown that CD34(+) cells cycle slower than CD34(-) cells. Generation times for CD34(+) and CD34(-) cells were 24.7 +/- 0.8 h and 15.1 +/- 0.9 h (+/-SD, n = 5), respectively. The 20-fold increase in CD34(+) cell numbers at Day 6 could be attributed to a high CD34(+) cell renewal rate (91% +/- 2% per ision). Although cultures were initiated with highly purified CD34(+) cells (approximately 96%), CD34(-) numbers had expanded rapidly by Day 6. This rapid expansion could be explained by their short generation time as well as a small fraction of CD34(+) cells (approximately 5%) that differentiated into CD34(-) cells. Multitype ision tracking provides a detailed analysis of multipotent cell differentiation dynamics.
Ex vivo expansion of cord blood progenitors impairs their short-term and long-term repopulating activity associated with transcriptional dysregulation of signalling networks
Publisher: Wiley
Date: 20-03-2012
Analysis of cardiac stem cell self-renewal dynamics in serum-free medium by single cell lineage tracking
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.SCR.2018.02.004
Abstract: Cardiac colony forming unit-fibroblasts (cCFU-F) are a population of stromal cells residing within the SCA1
The method to generate pulsatile circulatory fluid flow using microfluidics
Publisher: Elsevier BV
Date: 2021
GSK-3β inhibition promotes engraftment of ex vivo-expanded hematopoietic stem cells and modulates gene expression
Publisher: Oxford University Press (OUP)
Date: 2011
DOI: 10.1002/STEM.551
Abstract: Glycogen synthase kinase-3β (GSK-3β) has been identified as an important regulator of stem cell function acting through activation of the wingless (Wnt) pathway. Here, we report that treatment with an inhibitor of GSK-3β, 6-bromoindirubin 3′-oxime (BIO) delayed cell cycle progression by increasing cell cycle time. BIO treatment resulted in the accumulation of late iding cells enriched with primitive progenitor cells retaining the ability for sustained proliferation. In vivo analysis using a Non-obese diabetic/severe combined immunodeficient (NOD/SCID) transplantation model has demonstrated that pretreatment with BIO promotes engraftment of ex vivo-expanded hematopoietic stem cells. BIO enhanced the engraftment of myeloid, lymphoid and primitive stem cell compartments. Limiting dilution analysis of SCID repopulating cells (SRC) revealed that BIO treatment increased human chimerism without increasing SRC frequency. Clonogenic analysis of human cells derived from the bone marrow of transplant recipient mice demonstrated that a higher level of human chimerism and cellularity was related to increased regeneration per SRC unit. Gene expression analysis showed that treatment with BIO did not modulate the expression of canonical Wnt target genes upregulated during cytokine-induced cell proliferation. BIO increased the expression of several genes regulating Notch and Tie2 signaling downregulated during ex vivo expansion, suggesting a role in improving stem cell engraftment. In addition, treatment with BIO upregulated CDK inhibitor p57 and downregulated cyclin D1, providing a possible mechanism for the delay seen in cell cycle progression. We conclude that transient, pharmacologic inhibition of GSK-3β provides a novel approach to improve engraftment of expanded HSC after stem cell transplantation.
Multi-type branching models to describe cell differentiation programs
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.JTBI.2011.02.006
Abstract: Cell proliferation and differentiation is described by a multi-type branching process, a probability model that defines the inheritance of cell type. Cell type is defined by (i) a repression index related to the time required for S-phase entry and (ii) phenotype as determined by cell markers and ision history. The inheritance of cell type is expressed as the expected number and type of progeny cells produced by a mother cell given her type. Expressions for the expected number and type of cells produced by a multi-cellular (bulk culture) system are derived from the general model by making the simplifying assumption that cell generation times are independent. The multi-type Smith-Martin model (MSM) makes the further assumption that cell generation times are lag-exponentially distributed with phenotype transitions occurring just before entry into S-phase. The inheritance-modified MSM (IMSM) model includes the influence of generation time memory so that mother and daughter generation times are correlated. The expansion of human cord blood CD34(+) cells by haematopoietic growth factors was ision tracked in bulk culture using carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE). The MSM model was fitted to ision tracking data to identify cell cycle length, and the rates of CD34 antigen down-regulation and apoptosis. The IMSM model was estimated for mouse granulocyte-macrophage progenitors using live cell imaging data. Multi-type branching models describe cell differentiation dynamics at both single- and multi-cell scales, providing a new paradigm for systematic analysis of stem and progenitor cell development.
Ex Vivo Expansion of Haematopoietic Stem Cells to Improve Engraftment in Stem Cell Transplantation
Publisher: Humana Press
Date: 2011
DOI: 10.1007/978-1-61779-182-6_17
Abstract: The efficient use of haematopoietic stem cells (HSC) for transplantation is often limited by the relatively low numbers of HSC collected. The ex vivo expansion of HSC for clinical use is a potentially valuable and safe approach to increase HSC numbers thereby increasing engraftment and reducing the risk of morbidity from infection. Here we describe a protocol for the robust ex vivo expansion of human CD34(+) HSC isolated from umbilical cord blood. The protocol described can efficiently generate large numbers of HSC. We also describe a flow cytometry-based method using high resolution ision tracking to characterise the kinetics of HSC growth and differentiation. Utilising the guidelines discussed, it is possible for investigators to use this protocol as presented or to modify it for their specific needs.
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