5 research outputs found

    A high-throughput micropatterning platform for screening of nanoparticles in regenerative engineering

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    Engineered nanoparticles (ENPs) have been gaining traction in the field of regenerative engineering due to their unique physical, chemical and biological properties that are able to modulate cellular behaviour by influencing cell adhesion, migration, and proliferation. These nanomaterial-cellular interactions are important in directing tissue regeneration processes at the cellular level. However, the usage of nanoparticles brings about safety concerns with regards to impairment of cellular dynamics. In this context, micropatterning platform has emerged as a high-throughput tool for assessing stress response of ENPs. This platform not only allow the analysis of biological responses to nanoparticles in a controlled and reproducible environment, but also provides the identification of subtle effects that may not be discernible using traditional methods. This abstract discusses how two commonly incorporated engineered nanoparticles in regenerative engineering, specifically zinc oxide (ZnO) and titanium dioxide (TiO2) have an influence on collective epithelial rotation via the use of micropatterned platform. The confinement of cells in geometrical constraints were achievable through the precise control over the geometry and size of the adhesive fibronectin islands which aids in cell attachment. Collective rotation is essential in tissue morphogenesis and wound healing, and disruption to this collective behaviour could lead to a wide range of biological dysregulations. Through this approach, it was observed that the micropatterned human keratinocytes clusters exhibited spontaneous rotation without external stimulus, at relatively constant uniform speeds of 10 μm/h. However, acute (6 h) exposure to non-cytotoxic doses of ZnO and TiO2 NPs (≤100 nm) resulted in a loss of directionality and slowing down of cell rotation, respectively. The loss in collective cell rotation (CCR) was determined to be attributed to reactive oxygen species (ROS)-induced proliferation by ZnO. While cell proliferation is desired in regenerative engineering, the generation of new, heterogeneous localised velocity fields by the increased cell density led to cell jamming within the epithelial units. On the other hand, the retardation of the velocity of TiO2-treated units was most likely as a result of degradation of membrane recycling integrins that are necessary for continued cell migration. This is because TiO2-treated units were found to induce autophagy, which has been reported to compete with endocytosis- driven recycling. Taken together, our findings offer nano-biological insights into the distinct signalling pathways exerted by different nanoparticles - ZnO NPs promoting cell proliferation, yet disrupting cell migration, and TiO2 NPs decreasing cell migration. This suggests that when it comes to the usage of ENPs in regenerative engineering, further studies have to be done to ensure that cellular dynamics are not compromised.Nanyang Technological Universit

    Elucidating the size-dependency of in vitro digested polystyrene microplastics on human intestinal cells health and function

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    The prevalence of microplastics (MPs) contamination in a broad spectrum of potable water sources has raised significant environmental and public health concerns. While evidence of ingested MPs bioaccumulation in the gastrointestinal tract (GIT) of aquatic and terrestrial organisms is mounting, the understanding of the effects of MPs on human gastrointestinal health remains scant. Herein, the potential deleterious biological effects of pristine and in vitro digested polystyrene (PS) MPs of varying sizes (i.e., 0.1, 1, and 10 µm) are systematically examined over a wide concentration range of 25–400 µg mL−1 on two human intestinal cell lines, namely Caco-2 and NCM 460. Specifically, significant internalization of 0.1 and 1 µm PS -MPs have been observed in both cell types 24 h postexposure. However, multiparametric dose and time-dependent analysis encompassing cell viability, reactive oxygen species (ROS), and nutrient absorption/metabolism measurement revealed no significant adversarial outcomes. Interestingly, it is found that the 0.1 µm PS-MPs can perturb redox homeostasis in NCM460 but not in Caco-2 cells. Based on the in vitro experimental boundaries and findings, it is concluded that ingested PS-MPs pose little acute cytotoxic harm to human gastrointestinal health

    Biocompatible ionic liquids in high-performing organic electrochemical transistors for ion detection and electrophysiological monitoring

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    Organic electrochemical transistors (OECTs) have recently attracted attention due to their high transconductance and low operating voltage, which makes them ideal for a wide range of biosensing applications. Poly-3,4-ethylenedioxythiophene:poly-4-styrenesulfonate (PEDOT:PSS) is a typical material used as the active channel layer in OECTs. Pristine PEDOT:PSS has poor electrical conductivity and additives are typically introduced to improve its conductivity and OECT performance. However, these additives are mostly either toxic or not proved to be biocompatible. Herein, a biocompatible ionic liquid [MTEOA][MeOSO3] is demonstrated to be an effective additive to enhance the performance of PEDOT:PSS based OECTs. The influence of [MTEOA][MeOSO3] on the conductivity, morphology and the redox process of PEDOT:PSS are investigated. The PEDOT:PSS/[MTEOA][MeOSO3] based OECT exhibits high transconductance (22.3 ± 4.5 mS μm-1), high μC* (the product of mobility μ and volumetric capacitance C*) (283.80 ± 29.66 F cm-1 V-1 s-1), fast response time (~40.57 μs) and excellent switching cyclical stability. Next, the integration of sodium (Na+) and potassium (K+) ion-selective membranes with the OECTs is demonstrated, enabling selective ions detection in the physiological range. In addition, flexible OECTs are designed for electrophysiological (ECG) signals acquisition. These OECTs have shown robust performance against physical deformation and successfully recorded high quality ECG signals.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Submitted/Accepted versionW.L.L. would like to acknowledge funding support from Ministry of Education (MOE) under AcRF Tier 2 Grant (MOE2019-T2-2-106) and National Robotics Programme (W1925d0106). We would like to acknowledge the Facility for Analysis, Characterization, Testing and Simulation (FACTS) and the School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, for use of their GIWAXS, XPS and AFM facilities

    Large-Scale Whole-Genome Sequencing of Three Diverse Asian Populations in Singapore

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    Because of Singapore's unique history of immigration, whole-genome sequence analysis of 4,810 Singaporeans provides a snapshot of the genetic diversity across East, Southeast, and South Asia.</p

    Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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