ORCID Profile
0000-0002-3328-0489
Current Organisation
National University of Singapore
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: AIP Publishing
Date: 09-2020
DOI: 10.1063/5.0012185
Abstract: Dysregulation of the human microbiome has been linked to various disease states, which has galvanized the efforts to modulate human health through microbiomes. Currently, human microbiome research is going through several phases to identify the constituent components of the microbiome, associate microbiome changes with physiological and pathological states, understand causative relationships, and finally translate this knowledge into therapeutics and diagnostics. The convergence of microfluidic technologies with molecular and cell profiling, microbiology, and tissue engineering can potentially be applied to these different phases of microbiome research to overcome the existing challenges faced by conventional approaches. The goal of this paper is to discuss and highlight the opportunities of applying different microfluidic technologies to specific areas of microbiome research as well as unique challenges that microfluidics must overcome when working with microbiome-relevant biological materials, e.g., micro-organisms, host tissues, and fluids. We will discuss the applicability of integrated microfluidic systems for processing biological s les for genomic sequencing analyses. For functional analysis of the microbiota, we will cover state-of-the-art microfluidic devices for microbiota cultivation and functional measurements. Finally, we highlight the use of organs-on-chips to model various microbiome–host tissue interactions. We envision that microfluidic technologies may hold great promise in advancing the knowledge on the interplay between microbiome and human health, as well as its eventual translation into microbiome-based diagnostics and therapeutics.
Publisher: Springer Science and Business Media LLC
Date: 28-11-2013
DOI: 10.1007/S10544-013-9830-4
Abstract: This paper reports a lab-on-a-chip for the detection of Sarin nerve agent based on rapid electrochemical detection. The chemical warfare agent Sarin (C₄H₁₀FO₂P, O-isopropyl methylphosphonofluoridate) is a highly toxic organophosphate that induces rapid respiratory depression, seizures and death within minutes of inhalation. As purified Sarin is colourless, odourless, water soluble and a easily disseminated nerve agent, it has been used as a weapon in terrorist or military attacks. To ascertain whether potable water supplies have been adulterated with this extremely potent poison, an inexpensive, sensitive and easy to use portable test kit would be of interest to first responders investigating such attacks. We report here an erometric-based approach for detecting trace amounts of Sarin in water s les using a screen-printed electrode (SPE) integrated in a microfluidic chip. Enzymatic inhibition was obtained by exposing the immobilised biosensor in the microfluidic platform to Sarin in water s les. With the aid of cobalt phthalocyanine modified SPE, the device could detect Sarin at part-per-billion levels with concentration as low as 1 nM. The detection method reported here represents a significant improvement over the authors'previous optical-based detection method.
Publisher: SPIE
Date: 27-12-2006
DOI: 10.1117/12.697234
Publisher: Wiley
Date: 22-07-2022
Abstract: Despite recent advances in biofabrication, recapitulating complex architectures of cell-laden vascular constructs remains challenging. To date, biofabricated vascular models have not yet realized four fundamental attributes of native vasculatures simultaneously: freestanding, branching, multilayered, and perfusable. In this work, a microfluidics-enabled molding technique combined with coaxial bioprinting to fabricate anatomically relevant, cell-laden vascular models consisting of hydrogels is developed. By using 3D porous molds of poly(ethylene glycol) diacrylate as casting templates that gradually release calcium ions as a crosslinking agent, freestanding, and perfusable vascular constructs of complex geometries are fabricated. The bioinks can be tailored to improve the compatibility with specific vascular cells and to tune the mechanical modulus mimicking native blood vessels. Crucially, the integration of relevant vascular cells (such as smooth muscle cells and endothelial cells) in a multilayer and biomimetic configuration is highlighted. It is also demonstrated that the fabricated freestanding vessels are amenable for testing percutaneous coronary interventions (i.e., drug-eluting balloons and stents) under physiological mechanical states such as stretching and bending. Overall, a versatile fabrication technique with multifaceted possibilities of generating biomimetic vascular models that can benefit future research in mechanistic understanding of cardiovascular diseases and the development of therapeutic interventions is introduced.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B800438B
Abstract: Sarin (C(4)H(10)FO(2)P,O-isopropyl methylphosphonofluoridate) is a colourless, odourless and highly toxic phosphonate that acts as a cholinesterase inhibitor and disrupts neuromuscular transmission. Sarin and related phosphonates are chemical warfare agents, and there is a possibility of their application in a military or terrorist attack. This paper reports a lab-on-a-chip device for detecting a trace amount of sarin in a small volume of blood. The device should allow early detection of sarin exposure during medical triage to differentiate between those requiring medical treatment from mass psychogenic illness cases. The device is based on continuous-flow microfluidics with sequential stages for lysis of whole blood, regeneration of free nerve agent from its complex with blood cholinesterase, protein precipitation, filtration, enzyme-assisted reaction and optical detection. Whole blood was first mixed with a nerve gas regeneration agent, followed by a protein precipitation step. Subsequently, the lysed product was filtered on the chip in two steps to remove particulates and fluoride ions. The filtered blood s le was then tested for trace levels of regenerated sarin using immobilised cholinesterase on the chip. Activity of immobilised cholinesterase was monitored by the enzyme-assisted reaction of a substrate and reaction of the end-product with a chromophore. Resultant changes in chromophore-induced absorbance were recorded on the chip using a Z-shaped optical window. Loss of enzyme activity obtained prior and after passage of the treated blood s le, as shown by a decrease in recorded absorbance values, indicates the presence of either free or regenerated sarin in the blood s le. The device was fabricated in PMMA (polymethylmethacrylate) using CO(2)-laser micromachining. This paper reports the testing results of the different stages, as well as the whole device with all stages in the required assay sequence. The results demonstrate the potential use of a field-deployable hand-held device for point-of-care triage of suspected nerve agent casualties.
Publisher: Elsevier BV
Date: 11-2010
Publisher: ASMEDC
Date: 2009
Abstract: Sustainable development is a process involving the society, the environment and the economy to meet human needs while preserving the environment. Sustainable development not only addresses the present needs but also the future needs of humanity. Lab on a chip technologies play an important role in this process. This paper reports ex les of low-cost polymeric lab-on-a-chip (LOC) devices for sustainable development in food supply, namely the detection of genetically modified organisms (GMOs) and the detection of insecticides in agriculture. As the first ex le, the paper presents a close-loop ferrofluid-driven LOC for rapid lification and detection of GMOs. Polymerase chain reaction (PCR) s le was contained in a circular closed microchannel and driven by magnetic force generated by an external magnet through a small oil-based ferrofluid plug. Successful lification of genetically modified soya and maize were achieved in less than 13 minutes. The LOC provides a cost saving and less time-consuming way to conduct preliminary screening of GMOs. As the second ex le, the paper reports a LOC for detection of organophosphorus insecticides for occupational hygiene in agriculture. Nerve agent sarin diluted in water was used to test the device concept. The s le was tested for trace levels of regenerated sarin using immobilised cholinesterase on the chip. Activity of immobilised cholinesterase was monitored by enzyme-assisted reaction of a substrate and reaction of the end-product with a chromophore. Resultant changes in chromophore-induced absorbance were recorded on the. Loss of enzyme activity obtained prior and after passage of the treated blood s le, as shown by a decrease in recorded absorbance values, indicates the presence of either free or regenerated nerve agent in the s le.
Publisher: Cold Spring Harbor Laboratory
Date: 28-09-2021
DOI: 10.1101/2021.09.27.461981
Abstract: Anatomically and biologically relevant vascular models are critical to progress our understanding of cardiovascular diseases (CVDs) that can lead to effective therapies. Despite advances in 3D bioprinting, recapitulating complex architectures ( i.e ., freestanding, branching, multilayered, perfusable) of a cell-laden vascular construct remains technically challenging, and the development of new techniques that can recapitulate both anatomical and biological features of blood vessels is of paramount importance. In this work, we introduce a unique, microfluidics-enabled molding technique that allows us to fabricate anatomically-relevant, cell-laden hydrogel vascular models. Our approach employed 3D-printed porous molds of poly(ethylene glycol) diacrylate (PEGDA) as templates to cast alginate-containing bioinks. Due to the porous and aqueous nature of the PEGDA mold, the calcium ion (Ca 2+ ) was diffusively released to crosslink the bioinks to create hollow structures. Applying this technique, multiscale, multilayered vascular constructs that were freestanding and perfusable were readily fabricated using cell-compatible bioinks ( i.e ., alginate and gelatin methacryloyl (GelMA)). The bioinks were also readily customizable to either improve the compatibility with specific vascular cells or tune the mechanical modulus to mimic native blood vessels. Importantly, we successfully integrated smooth muscle cells and endothelial cells in a biomimetic organization within our vessel constructs and demonstrated a significant increase in monocyte adhesion upon stimulation with an inflammatory cytokine, tumor necrosis factor-alpha (TNF-α). We also demonstrated that the fabricated vessels were amenable for testing percutaneous coronary interventions ( i.e ., drug-eluting balloons and stents) under physiologically-relevant mechanical states, such as vessel stretching and bending. Overall, we introduce a versatile fabrication technique with multi-faceted possibilities of generating biomimetic vascular models that can benefit future research in mechanistic understanding of CVD progression and the development of therapeutic interventions.
No related grants have been discovered for Hsih-Yin Tan.