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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 version W.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.

Cast cured formulations have emerged as an important enabling platform for the manufacturing of large calibre energetic systems. In this study, we report a novel hybrid oligomer containing fluoroalkyl and azido moieties, 1,4-bis((2-azido-4,4,5,5,6,6,7,7,7-nonafluoroheptyl)oxy)butane (BANFHOB) as an energetic plasticizer for a cast curable fluoropolymer (FP) binder. The fluoroalkyl and azido groups impart oxidizing and energy release properties to the plasticizer. BANFHOB was synthesized by cationic ring-opening polymerization of 2,2,3,3,4,4,5,5,5-nonafluoropentyloxirane, followed by end-group modification of the terminal hydroxyl groups into azides. BANFHOB with a number average molecular weight of 698 g/mol exhibited low glass transition temperature (Tg = –78.2 °C) and viscosity (η25°C = 71 mPa s). Compared to a conventional plasticizer (dibutyl phthalate), BANFHOB showed good miscibility with FP and exhibited excellent plasticizing effects by significantly reducing the Tg and viscosity of FP. BANFHOB also exhibited promising plasticizing effects on a commercial fluoropolymer binder (Viton®), demonstrating its application potential for fluoropolymer-based formulations. Submitted/Accepted version

The widespread use of engineered nanomaterials (ENMs) in food products necessitates the understanding of their impact on the gastrointestinal tract (GIT). Herein, we screened several representative food-borne comparator ENMs (i.e. ZnO, SiO2 and TiO2 nanoparticles (NPs)) and report that human colon cancer cells can insidiously exploit ZnO NP-induced adaptive response to acquire resistance against several chemotherapeutic drugs. By employing a conditioning and challenge treatment regime, we demonstrate that repeated exposure to a non-toxic dose of ZnO NPs (20 μM) could dampen the efficacy of cisplatin, paclitaxel and doxorubicin by 10-50% in monolayer culture and 3D spheroids of human colon adenocarcinoma cells. Structure-activity relationship studies revealed a complex interplay between nanoparticle surface chemistry and cell type in determining the chemoresistance-inducing effect, with silica coated ZnO NPs having a negligible influence on the anticancer treatment. Mechanistically, we showed that the pro-survival paracrine signaling was potentiated and propagated by a subset of ZnO NP "stressed" (Zn2++/ROS+) cells to the surrounding "bystander" (Zn2++/ROS-) cells. Transcriptome profiling, bioinformatics analysis and siRNA gene knockdown experiments revealed the nuclear factor erythroid 2-related factor 2 (Nrf2) as the key modulator of the ZnO NP-induced drug resistance. Our findings suggest that a ROS-inducing ENM can emerge as a nano-stressor, capable of regulating the chemosensitivity of colon cancer cells. Nanyang Technological University Published version Nanyang Technological University—Harvard School of Public Health Initiative for Sustainable Nanotechnology (NTU‐Harvard SusNano; NTU-HSPH-18002)

High entropy materials made up of dissimilar elements have enormous potentials in various fields and applications such as catalysis, energy generation and bioengineering. Developments of facile rapid synthesis routes toward functional multicomponent nanoparticles (NPs) of metals and ceramics with control of single/mixed crystalline structure configurations as well as understanding their transformative behaviors to enable unexpected properties, however, has remained challenging. Here a transient laser heating strategy to generate high entropy metal alloy, oxide, and nitride nanoparticles (HE-A/O/N NPs) is described. Laser irradiation of the identical metal salt mixture under different millisecond heating times provides direct control of cooling rates and thereby results in HEA NPs with tunable single- and multiphasic solid solution characteristics, atomic compositions, nanoparticle morphologies, and physicochemical properties. Extending the elemental selection to nitride-forming precursors enables laser-induced carbothermal reduction and nitridation of high entropy tetragonal rutile oxide nanoparticlesNPs to the cubic rock salt nitride phase. The combination of laser heating with spatially resolved X-ray diffraction facilitates combinatorial studies of phase transitions and reaction pathways of multicomponent nanoparticles. These findings provide a general strategy to design nonequilibrium multicomponent metal alloys and ceramic materials amalgamations for fundamental studies and practical applications such as carbon nanotube growth, water splitting, and antimicrobial applications. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Nanyang Technological University National Research Foundation (NRF) This work was supported by a Singapore Ministry of Education AcRF Tier 2 grant (MOE-T2EP50221-0017) and a startup grant from Nanyang Technological University, Singapore. S.M. and W.M.Jr. acknowledge financial support from the National Research Foundation of Singapore (NRF) Investigatorship Award (NRFI 2017-08) and the Agency for Science, Technology and Research (A*STAR) grant (A20H3g2140).

Multicomponent inorganic nanoparticles made up of dissimilar elements have enormous potentials in various fields and applications such as catalysis, energy generation and bioengineering. Developments of facile rapid synthesis routes toward functional multicomponent nanoparticles of metals and ceramics with control of single/mixed crystalline structure configurations as well as understanding their transformative behaviors to enable unexpected properties, however, have remained challenging. Here we describe a transient laser heating strategy to generate multicomponent metal alloy, oxide and nitride nanoparticles. Laser irradiation of the identical metal salt mixture under different millisecond heating times provides direct control of cooling rates and thereby results in multicomponent alloy nanoparticles with tunable single- and multiphasic solid solution characteristics, atomic compositions, nanoparticle morphologies and physicochemical properties. Extending the elemental selection to nitride-forming precursors enables laser-induced carbothermal reduction and nitridation of multicomponent tetragonal rutile oxide nanoparticles to the cubic rock salt nitride phase. The combination of laser heating with spatially resolved X-ray diffraction facilitates combinatorial studies of phase transitions and reaction pathways of multicomponent nanoparticles. These findings provide a general strategy to design nonequilibrium multicomponent metal alloys and ceramic materials amalgamations for fundamental studies and practical applications such as carbon nanotube growth, water splitting and antimicrobial applications.

Mesoporous silica nanoparticles have highly versatile structural properties that are suitable for a plethora of applications including catalysis, separation and nanotherapeutics. We report a one-pot synthesis strategy that generates bimodal mesoporous silica nanoparticles via co-assembly of a structure-directing Gemini surfactant (C16-3-16) with tetraethoxysilane/(3-aminopropyl)triethoxysilane-derived sol additive. Synthesis temperature enables control of the nanoparticle shape, structure and mesopore architecture. Variations of the aminosilane/alkylsilane molar ratio further enables programmable adjustments of hollow to dense nanoparticle morphologies, bimodal pore sizes and surface chemistry. The resultant Gemini-directed aminated mesoporous silica nanoparticles have excellent carbon dioxide adsorption capacities and antimicrobial properties against E. coli. Our results provide enhanced understandings in the structure formation of multiscale mesoporous inorganic materials that are desirable for numerous applications such as carbon sequestration, water remediation and biomedical-related applications.

The development of environmentally benign hydrometallurgical processes to treat spent lithium-ion batteries (LIBs) is a critical aspect of the electronic-waste circular economy. Herein, as an alternative to the highly explosive H2O2, discarded orange peel powder (OP) is valorized as a green reductant for the leaching of industrially produced LIBs scraps in citric acid (H3Cit) lixiviant. The reductive potential of the cellulose- and antioxidant-rich OP was validated using the 3,5-dinitrosalicylic acid and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid assays. Leaching parameters such as OP concentration (200 mg), processing temperature (100 °C), H3Cit concentration (1.5 M), reaction duration (4 h), and slurry density (25 g/mL) were systematically optimized to achieve 80-99% leaching efficiencies of Ni, Mn, Co, and Li from the LIB "black mass". Importantly, solid side-streams generated by the OP-enabled leaching displayed negligible cytotoxicity in three different human cell lines, suggesting that the process is environmentally safe. As a proof of concept, Co(OH)2 was selectively recovered from the green lixiviant and subsequently utilized to fabricate new batches of LiCoO2 (LCO) coin cell batteries. Galvanostatic charge-discharge test revealed that the regenerated batteries exhibited initial charge and discharge values of 120 and 103 mAh/g, respectively, which is comparable to the performance of commercial LCO batteries. The use of fruit peel waste to recover valuable metals from spent LIBs is an effective, ecofriendly, and sustainable strategy to minimize the environmental footprint of both waste types. Ministry of National Development (MND) National Research Foundation (NRF) Accepted version SCARCE is supported by the National Research Foundation, Prime Minister’s Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of the Environment and Water Resource, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability−Integration Fund (award no. USS-IF-2018-4).

Reuse of electronic wastes is a critical aspect for a more sustainable circular economy as it provides the simplest and most direct route to extend the lifespan of non-renewable resources. Herein, the distinctive surface and micro topographical features of computer electronic-plastic (E-plastic) scraps were unconventionally repurposed as a substrate material to guide the growth and differentiation of human adipose-derived mesenchymal stem cells (ADSCs). Specifically, the E-plastics were scavenged from discarded computer components such as light diffuser plate (polyacrylates), prismatic sheet (polyethylene terephthalate), and keyboards (acrylonitrile butadiene styrene) were cleaned, sterilized, and systematically characterized to determine the identity of the plastics, chemical constituents, surface features, and leaching characteristics. Multiparametric analysis revealed that all the E-plastics could preserve stem-cell phenotype and maintain cell growth over 2 weeks, rivalling the performance of commercial tissue-culture treated plates as cell culture plastics. Interestingly, compared to commercial tissue-culture treated plastics and in a competitive adipogenic and osteogenic differentiation environment, ADSCs cultured on the keyboard and light diffuser plastics favoured bone cells formation while the grating-like microstructures of the prismatic sheet promoted fat cells differentiation via the process of contact guidance. Our findings point to the real possibility of utilizing discarded computer plastics as a "waste-to-resource" material to programme stem cell fate without further processing nor biochemical modification, thus providing an innovative second-life option for E-plastics from personal computers. National Environmental Agency (NEA) National Research Foundation (NRF) This research is supported by the National Research Foundation, Singapore, and National Environment Agency, Singapore under its Closing the Waste Loop Funding Initiative (Award No. USS-IF-2018-4).

The development of a novel energetic block co-polymer of Glycidyl Azide Polymer (GAP) and the fluoropolymer (FP) using the Boron trifluoride-tetrahydrofuranate complex/diol initiator system is reported herein. Well-defined compositions of the GAP-FP co-polymers in two different GAP to FP ratios (1:1 & 1:3) were synthesized by tailoring the desired molecular weights of each block in the co-polymer, demonstrating the synthetic versatility of such a co-polymer system. The resultant GAP-FP co-polymers represent a unique hybrid binder system with tunable energy releasing and oxidizing potentials intended for metallized formulations. Thermogravimetric analysis showed that the carbonaceous residue usually formed from the decomposition of GAP could be reduced significantly by the copolymerization with FP. Isoconversional method of kinetic analysis of the GAP-FP copolymers revealed an increasing dependence of the effective activation energy on the extent of conversion. The increasing dependence suggested a mechanism of the competing reactions that were found to be between the reactions of fluoropolymer triggered oxidation and intermolecular crosslinking of the polyimine intermediates formed from GAP decomposition that ultimately resulted in the reduction of the carbonaceous residue. Submitted/Accepted version

Nano-enabled, toner-based printing equipment emit nanoparticles during operation. The bioactivity of these nanoparticles as documented in a plethora of published toxicological studies raises concerns about their potential health effects. These include pro-inflammatory effects that can lead to adverse epigenetic alterations and cardiovascular disorders in rats. At the same time, their potential to alter DNA repair pathways at realistic doses remains unclear. In this study, size-fractionated, airborne particles from a printer center in Singapore were sampled and characterized. The PM0.1 size fraction (particles with an aerodynamic diameter less than 100 nm) of printer center particles (PCP) were then administered to human lung adenocarcinoma (Calu-3) or lymphoblastoid (TK6) cells. We evaluated plasma membrane integrity, mitochondrial activity, and intracellular reactive oxygen species (ROS) generation. Moreover, we quantified DNA damage and alterations in the cells' capacity to repair 6 distinct types of DNA lesions. Results show that PCP altered the ability of Calu-3 cells to repair 8oxoG:C lesions and perform nucleotide excision repair, in the absence of acute cytotoxicity or DNA damage. Alterations in DNA repair capacity have been correlated with the risk of various diseases, including cancer, therefore further genotoxicity studies are needed to assess the potential risks of PCP exposure, at both occupational settings and at the end-consumer level. Nanyang Technological University Submitted/Accepted version Reported research has received support from the Nanyang Technological University-Harvard T. H. Chan School of Public Health Initiative for Sustainable Nanotechnology (NTU-Harvard SusNano; NTU-HSPH 18001). Engineered nanomaterials used in the research were characterized by the Engineered Nanomaterials Resource and Coordination Core established at Harvard T. H. Chan School of Public Health (NIH grant # U24ES026946) as part of the Nanotechnology Health Implications Research (NHIR) Consortium. Z.D.N. and S.M.T. were supported by U01ES029520, and Z.D.N. was also supported by P30ES000002. Partial funding for D.B. was provided by the International Initiative for the Environment and Public Health Cyprus Program at the Harvard School of Public Health. QH was supported by China Scholarship Council #201804910248.

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.

The extensive use of electronic and electrical equipment and ever-increasing rate of renewal inevitably generate numerous e-waste plastics which need to be disposed of properly, and eliminating the brominated flame retardants (BFRs) present in them can significantly alleviate their environmental impact. In the present study, TBBPA-bis-(2,3-dibromo-2-methylpropyl ether) (TBBPA-DBMP), a novel tetrabromobisphenol A-derived BFR, was removed using an extraction process assisted by ultrasonic in alcohol extractants. Response Surface Methodology (RSM) achieved by support vector regression (SVR) was used to predict the optimum extraction conditions (extraction time, extraction temperature, liquid to solid ratio) in methanol and ethanol solvent, respectively. The maximum predicted extraction efficiencies of TBBPA-DBMP were 98.1% under the optimized conditions of 178 min, 180 mL/g, 66 °C in methanol and 99.5% under the optimized conditions of 150 min, 178 mL/g, 66 °C in ethanol. And the validity of predicted optimal extraction conditions was verified. The plastic matrix was capable of being recovered well after extraction (recovery rate > 90%). Moreover, shrinking core model was referred to conduct the kinetic analysis of the extraction, which demonstrates that the interface transfer and internal diffusion are the rate-controlling step in the extraction of TBBPA-DBMP in both methanol and ethanol extractants. Ministry of National Development (MND) National Environmental Agency (NEA) National Research Foundation (NRF) Published version This work was supported by the National Research Foundation, Prime Minister’s Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of Sustainability and the Environment, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability – Integration Fund (Award No. USS-IF-2018-4).

Chronic wounds are non-healing wounds characterized by a prolonged inflammation phase. Excessive inflammation leads to elevated protease levels and consequently to a decrease in growth factors at wound sites. Stem cell secretome therapy has been identified as a treatment strategy to modulate the microenvironment of chronic wounds via supplementation with anti-inflammatory/growth factors. However, there is a need to develop better secretome delivery systems that are able to encapsulate the secretome without denaturation, in a sustained manner, and that are fully biocompatible. To address this gap, a recombinant squid suckerin-spider silk fusion protein is developed with cell-adhesion motifs capable of thermal gelation at physiological temperatures to form hydrogels for encapsulation and subsequent release of the stem cell secretome. Freeze-thaw treatment of the protein hydrogel results in a modified porous cryogel that maintains slow degradation and sustained secretome release. Chronic wounds of diabetic mice treated with the secretome-laden cryogel display increased wound closure, presence of endothelial cells, granulation wound tissue thickness, and reduced inflammation with no fibrotic scar formation. Overall, these in vivo indicators of wound healing demonstrate that the fusion protein hydrogel displays remarkable potential as a delivery system for secretome-assisted chronic wound healing. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) National Research Foundation (NRF) This research was supported by a Singapore Ministry of Education Academic Research Fund (AcRF) Tier 2 grant (#MOE 2018-T2-1-043). R.M.S.acknowledges the support of A*STAR core funding and Singapore National Research Foundation, NRF-SIS “SingMass.

Two-dimensional (2D) nanomaterials (NM) have emerged as promising platforms for antibacterial applications. However, the inherent “flatness” of 2D NM often limits the loading of antimicrobial components needed for synergistic bactericidal actions. Here, inspired by the highly ornamented siliceous frustules of diatoms, we prepared 2D ultrathin (

Mechanistic understanding of atherosclerosis is largely hampered by the lack of a suitable in vitro human arterial model that recapitulates the arterial wall structure, and the interplay between different cell types and the surrounding extracellular matrix (ECM). This work introduces a novel microfluidic endothelial cell (EC)-smooth muscle cell (SMC) 3D co-culture platform that replicates the structural and biological aspects of the human arterial wall for modeling early atherosclerosis. Using a modified surface tension-based ECM patterning method, we established a well-defined intima-media-like structure, and identified an ECM composition (collagen I and Matrigel mixture) that retains the SMCs in a quiescent and aligned state, characteristic of a healthy artery. Endothelial stimulation with cytokines (IL-1β and TNFα) and oxidized low-density lipoprotein (oxLDL) was performed on-chip to study various early atherogenic events including endothelial inflammation (ICAM-1 expression), EC/SMC oxLDL uptake, SMC migration, and monocyte-EC adhesion. As a proof-of-concept for drug screening applications, we demonstrated the atheroprotective effects of vitamin D (1,25(OH)2D3) and metformin in mitigating cytokine-induced monocyte-EC adhesion and SMC migration. Overall, the developed arterial wall model facilitates quantitative and multi-factorial studies of EC and SMC phenotype in an atherogenic environment, and can be readily used as a platform technology to reconstitute multi-layered ECM tissue biointerfaces. Ministry of Education (MOE) Nanyang Technological University National Medical Research Council (NMRC) We would like to acknowledge financial support from the Singapore Ministry of Education Academic Research Fund Tier 1 (RG53/18) awarded to H. W. H., and National Medical Research Council (NMRC) Clinician Scientist Award (CSAINV17nov009) awarded to R. D. C. S. is supported by the NTU Interdisciplinary Graduate Programme Scholarship. H. C. is supported by the NTU Research Scholarship.

The rise of electronic waste (e-waste) generation around the globe has become a major concern in recent times and its recycling is mostly focused on the recovery of valuable metals, such as gold, silver, and copper, etc. However, e-waste consists of a significant weight fraction of plastics (25-30%) which are either discarded or incinerated. There is a growing need for recycling of these e-waste plastics. The majority of them are made from high-quality polymers (composites), such as acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS), polycarbonate (PC), polyamide (PA), polypropylene (PP) and epoxies. These plastics are often contaminated with hazardous materials, such as brominated flame retardants (BFRs) and heavy metals (such as Pb and Hg). Under any thermal stress (thermal degradation), the Br present in the e-waste plastics produces environmentally hazardous pollutants, such as hydrogen bromide or polybrominated diphenyl ethers/furans (PBDE/Fs). The discarded plastics can lead to the leaching of toxins into the environment. It is important to remove the toxins from the e-waste plastics before recycling. This review article gives a detailed account of e-waste plastics recycling and recovery using thermochemical processes, such as extraction (at elevated temperature), incineration (combustion), hydrolysis, and pyrolysis (catalytic/non catalytic). A basic framework of the existing processes has been established by reviewing the most interesting findings in recent times and the prospects that they open in the field recycling of e-waste plastics. Ministry of National Development (MND) National Environmental Agency (NEA) National Research Foundation (NRF) Authors would like to thank financial support from National Research Foundation, Prime Minister’s Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of Sustainability and the Environment, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability e Integration Fund (Award No. USS-IF-2018-4).

The potential genotoxic effects of engineered nanomaterials (ENMs) may occur through the induction of DNA damage or the disruption of DNA repair processes. Inefficient DNA repair may lead to the accumulation of DNA lesions and has been linked to various diseases, including cancer. Most studies so far have focused on understanding the nanogenotoxicity of ENM-induced damages to DNA, whereas the effects on DNA repair have been widely overlooked. The recently developed fluorescence multiplex-host-cell reactivation (FM-HCR) assay allows for the direct quantification of multiple DNA repair pathways in living cells and offers a great opportunity to address this methodological gap. Herein an FM-HCR-based method is developed to screen the impact of ENMs on six major DNA repair pathways using suspended or adherent cells. The sensitivity and efficiency of this DNA repair screening method were demonstrated in case studies using primary human small airway epithelial cells and TK6 cells exposed to various model ENMs (CuO, ZnO, and Ga2O3) at subcytotoxic doses. It was shown that ENMs may inhibit nucleotide-excision repair, base-excision repair, and the repair of oxidative damage by DNA glycosylases in TK6 cells, even in the absence of significant genomic DNA damage. It is of note that the DNA repair capacity was increased by some ENMs, whereas it was suppressed by others. Overall, this method can be part of a multitier, in vitro hazard assessment of ENMs as a functional, high-throughput platform that provides insights into the interplay of the properties of ENMs, the DNA repair efficiency, and the genomic stability.

Extracellular vesicles (EVs) are key mediators of communication among cells, and clinical utilities of EVs-based biomarkers remain limited due to difficulties in isolating EVs from whole blood reliably. We report a novel inertial-based microfluidic platform for direct isolation of nanoscale EVs (exosomes, 50 to 200 nm) and medium-sized EVs (microvesicles, 200 nm to 1 μm) from blood with high efficiency (three-fold increase in EV yield compared to ultracentrifugation). In a pilot clinical study of healthy (n = 5) and type 2 diabetes mellitus (T2DM, n = 9) subjects, we detected higher EV levels in T2DM patients (P < 0.05), and identified a subset of "high-risk" T2DM subjects with abnormally high (∼10-fold to 50-fold) amounts of platelet (CD41a+) or leukocyte-derived (CD45+) EVs. Our in vitro endothelial cell assay further revealed that EVs from "high-risk" T2DM subjects induced significantly higher vascular inflammation (ICAM-1 expression) (P < 0.05) as compared to healthy and non-"high-risk" T2DM subjects, reflecting a pro-inflammatory phenotype. Overall, the EV isolation tool is scalable, and requires less manual labour, cost and processing time. This enables further development of EV-based diagnostics, whereby a combined immunological and functional phenotyping strategy can potentially be used for rapid vascular risk stratification in T2DM. Ministry of Education (MOE) Nanyang Technological University Singapore-MIT Alliance for Research and Technology (SMART) H. W. H. would like to acknowledge the kind financial support from SMART Innovation Centre (ING-000539 BIO IGN and ING-001058 BIO IGN), Singapore Ministry of Education (MOE) Academic Research Fund Tier 1 (RG53/18), as well as A. Menarini Biomarkers Singapore Pte Ltd. S. Y. L would like to acknowledge support from the NTU Research Scholarship.

The huge consumption of modern plastic with improper disposals has posed a great threat to the environment and human beings. To put these post-consumer plastics into the recycling chain, laser induced breakdown spectroscopy (LIBS) has been established as a potential tool for rapid grading of plastics online. Meanwhile, LIBS is a powerful tool for plastic investigations in the laboratory with the capacity of simultaneous qualitative and quantitative analysis. The present review describes the development and prospect of plastic investigations using LIBS, highlighting the intrinsic advantages of LIBS for plastic recycling. Moreover, the selection of hardware components and analysis methods are discussed, which may help to start a research on plastic using LIBS. National Environmental Agency (NEA) National Research Foundation (NRF) The authors are grateful for the financial support from SCARCE, which is supported by the National Research Foundationgs2:, Prime Minister's Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of Sustainability and the Environment, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability - Integration Fund (Award No. USS-IF-2018-4).

Three-dimensional (3D) biomaterials with physiologically relevant and experimentally tractable biomechanical features are important platforms to advance our understanding of the influence of tissue mechanics in disease progression. Herein, an interpenetrating network (IPN) of collagen and alginate 3D culture system with tunable extracellular microstructure and mechanics is exploited as a tumor stroma proxy to study phenotypic plasticity of colorectal cancer-associated fibroblasts (CAF). In combination with Next Generation Sequencing (NGS) data analysis, we demonstrated that tuning the storage modulus of the IPN hydrogel between 49 and 419 Pa can trigger a reversible switch between an inflammatory (i-state, α-SMAlowIL-6high) and myofibroblastic (m-state, α-SMAhighIL-6low) state in CAF that is dependent on the polymer network confinement effect and ROS-HIF1-α mechanotransduction signaling axis. Secretome from m-state CAF upregulated several epithelial-mesenchymal-transition (EMT) transcripts and induced robust scattering in DLD-1, HCT116, and SW480 human colorectal adenocarcinoma, while the EMT-inducing capacity is muted in i-state CAF, suggestive of an anti-tumorigenic role. Our findings were further validated through Gene Expression Profiling Interactive Analysis (GEPIA), which showed that cytokines secreted at higher levels by i-state CAF are correlated (p Statement of significance The communication between cancer cells and cancer-associated fibroblasts (CAF) contributes to tumor metastasis. CAF represent a diverse population of cellular subsets that can either promote or restrain tumor progression. However, the origin and cause of CAF heterogeneity remain elusive, limiting CAF-directed therapies for clinical use. We studied the dynamic phenotypes of CAF using a 3D physio-mimetic culture platform consisting of an interpenetrating collagen-alginate network. Combined with transcriptomic stratification and correlative analysis using cancer patient dataset, we showed phenotypic interconversion between inflammatory and myofibroblastic states, with anti- and pro-tumorigenic functions, in human colorectal CAF. This multidisciplinary study reveals the functional diversity of colorectal CAF caused by biophysical cues. The finding will influence the development of new CAF biomarkers and cancer therapies.

Despite being a rich source of bioactive compounds, the current exploitation of aquatic biomass is insufficient. Majority of the aquaculture industry side-streams are currently used for low-value purposes such as animal feed or composting material, with low economical returns. To maximize resource reuse and minimize waste generation, valorization efforts should be augmented with the aim to produce high-value products. Herein, we present a novel aquaculture wastes-derived multi-scale osteoconductive hybrid biocomposite that is composed of chemically crosslinked American bullfrog (Rana catesbeiana) skin-derived type I tropocollagen nanofibrils (~22.3 nm) network and functionalized with micronized (~1.6 μm) single-phase hydroxyapatite (HA) from discarded snakehead (Channa micropeltes) fish scales. The bioengineered construct is biocompatible, highly porous (>90%), and exhibits excellent osteoconductive properties, as indicated by robust adhesion and proliferation of human fetal osteoblastic 1.19 cell line (hFOB 1.19). Furthermore, increased expression level of osteo-related ALPL and BGLAP mRNA transcripts, as well as enhanced osteocalcin immunoreactivity and increasing Alizarin red S staining coverage on the hybrid biocomposite was observed over 21 days of culture. Collectively, the devised "waste-to-resource" platform represents a sustainable waste valorization strategy that is amendable for advanced bone repair and regeneration applications. Ministry of Education (MOE) The authors gratefully acknowledge support from the Singapore Ministry of Education (MOE) Academic Research Fund Tier 1 (RG38/20 2020T1001152).

Simple Summary Human cells can communicate with each other by releasing small packets of protein called ‘vesicles’ that are absorbed by other cells nearby and at distant locations, leading to major changes in biological activity. This is also the case for cancer cells within developing tumours, which become starved of oxygen when they outgrow local blood supplies. We wondered whether oxygen starvation might cause cancer cells to alter the protein cargo they package into vesicles, which could play an important role in supporting further tumour development. We found that under oxygen-starved conditions, cancer cells release far higher numbers of vesicles that are actively packed with proteins known to enhance tumour survival, support distribution to other body sites, and suppress patient immune responses. Cancer vesicles could therefore be used to develop new diagnostic tests that inform doctors about disease progression, and may also represent useful drug targets for new types of patient treatment. Abstract Extracellular vesicles (EVs) mediate critical intercellular communication within healthy tissues, but are also exploited by tumour cells to promote angiogenesis, metastasis, and host immunosuppression under hypoxic stress. We hypothesize that hypoxic tumours synthesize hypoxia-sensitive proteins for packing into EVs to modulate their microenvironment for cancer progression. In the current report, we employed a heavy isotope pulse/trace quantitative proteomic approach to study hypoxia sensitive proteins in tumour-derived EVs protein. The results revealed that hypoxia stimulated cells to synthesize EVs proteins involved in enhancing tumour cell proliferation (NRSN2, WISP2, SPRX1, LCK), metastasis (GOLM1, STC1, MGAT5B), stemness (STC1, TMEM59), angiogenesis (ANGPTL4), and suppressing host immunity (CD70). In addition, functional clustering analyses revealed that tumour hypoxia was strongly associated with rapid synthesis and EV loading of lysosome-related hydrolases and membrane-trafficking proteins to enhance EVs secretion. Moreover, lung cancer-derived EVs were also enriched in signalling molecules capable of inducing epithelial-mesenchymal transition in recipient cancer cells to promote their migration and invasion. Together, these data indicate that lung-cancer-derived EVs can act as paracrine/autocrine mediators of tumorigenesis and metastasis in hypoxic microenvironments. Tumour EVs may, therefore, offer novel opportunities for useful biomarkers discovery and therapeutic targeting of different cancer types and at different stages according to microenvironmental conditions.

Plastics in waste electronics (E-plastics) account for approximately 20% of the entire global electronic waste (E-waste) stream. Most of the E-plastics are not recycled as the presence of toxic additives (e.g. heavy metals, brominated flame retardants (BFRs), antimony, etc.) have associated environmental and health concerns. However, the majority of the studies are focused on quantitative assessment of the toxic constituents in E-plastics, while empirical information regarding the potential toxic effects in humans is largely lacking. To gain a deeper appreciation into the toxicological profile of E-plastics, in situ time-dependent exposures of 6 different human cell lines to a panel of 8 representative E-plastics recovered from liquid crystal displays (LCD), keyboards, screen frames, and wire insulators were conducted. Although several hazardous elements (e.g. Pb, As, Sb, Zn, Cu, etc) were detected at concentrations that far exceed the limit values permitted by the Restriction of Hazardous Substances Directive and EU Directives in the panel E-plastics, in-depth analysis of the 144 unique cell viability data points and live-dead staining experiments suggest that the acute and sub-chronic toxic effects of E-plastics in direct contact with human cells are negligible. These observations agreed with the inductively coupled plasma-optical emission spectrometry data, which revealed that leaching of these toxic additives into the biological milieu is not sufficiently high to trigger a cytotoxic response up to a continuous culture period of 2 weeks. The novel insights gained from this study are posited to further clarify the uncertainty associated with the safety and circular economy implementation of E-plastics. Ministry of National Development (MND) Nanyang Technological University National Environmental Agency (NEA) National Research Foundation (NRF) This work was financially supported by a grant award from “Singapore eCEA Alliance for Research in Circular Economy (SCARCE)”, which is a joint lab set up between Nanyang Technological University (NTU, Singapore) and the French Alternative Energies and Atomic Energy Commission (CEA, France). SCARCE is supported by the National Research Foundation, Prime Minister’s Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of the Environment and Water Resource, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability e Integration Fund (award number USS-IF-2018-4).

Background: Extracellular vesicles (EVs) mediate critical intercellular communication within healthy tissues, but are also exploited by tumour cells to promote angiogenesis, metastasis, and host immunosuppression under hypoxic stress. We hypothesize that oxygen starvation in developing tumours induces specific hypoxia-sensitive proteins for packing into small EVs to modulate its microenvironment for cancer progression and enhance malignancy. Methods: We employed a heavy isotope pulse/trace quantitative proteomic approach to study hypoxia-sensitive EVs proteins (HSEPs) in hypoxic A549 lung adenocarcinoma cells derived small EVs (Results: Results revealed that hypoxia stimulated cancer cells to synthesize EVs proteins involved in enhancing tumour cell proliferation (NRSN2, WISP2, SPRX1, LCK), metastasis (GOLM1, STC1, MGAT5B), stemness (STC1, TMEM59), angiogenesis (ANGPTL4), and suppressing host immunity (CD70). In addition, functional clustering analyses revealed that tumour hypoxia was strongly associated with rapid synthesis and EV loading of lysosome-related hydrolases and membrane-trafficking proteins to enhance EVs secretion. Moreover, lung cancer-derived EVs were also enriched in signalling molecules capable of inducing epithelial-mesenchymal transition in recipient cancer cells to promote their migration and invasion. Conclusion: Together, these data indicate that lung cancer-derived EVs can act as paracrine/autocrine mediators of tumorigenesis and metastasis in hypoxic microenvironments. Tumour EVs may therefore offer novel opportunities for useful biomarkers discovery and therapeutic targeting of different cancer types and at different stages according to microenvironmental conditions.

We developed a hyperspectral imaging method that multiplexes measurements for adaptive compressive sensing, shortening imaging times by 10x. We simulate its application in cell monitoring, where short exposure and rapid processing are essential.

Transplantation of microencapsulated islet cells holds great potential for the treatment of type 1 diabetes mellitus. However, its clinical translation is hampered by the peri-transplantation loss of islet viability and functionality in the microcapsules. In this work, a novel islet cells biomimetic microencapsulant material that is based on the interpenetrating networks of alginate and extracellular matrix (ECM) hydrogel composite (AEC) is presented. The ECM component is derived from human lipoaspirate. In situ encapsulation of pancreatic β islet cells (MIN6 β-cells) can be achieved via ionotropic gelation of the alginate matrix and thermal-induced gelation of the pepsin-solubilized ECM pre-gel. Due to the enhanced cell-matrix interaction, islets encapsulated within the AEC microcapsules (≈640 µm) display sevenfold increase in cell growth over 1 week of culture and characteristic glucose-stimulated insulin response in vitro. The results show that the AEC microcapsule is a potent platform to bioaugment the performance of islet cells. Nanyang Technological University This research is supported by the HealthTech NTU Interdisciplinary Diabetes and Metabolic Diseases Grant (DMP-1604) awarded to C.Y.T.

Improving the efficiencies of organic compound degradations by catalytic materials is a challenging materials research field. In our research, we successfully synthesized cobalt-based polyoxometalates (CoV-POMs) via a simple crystallization-driven self-assembly method. The incorporation of the newly synthesized CoV-POMs into peroxymonosulphate (PMS), forming a mixture, greatly enhancing the catalytic activation for a complete degradation of dye solution. The positive synergic effect between CoV-POMs and PMS was substantiated by a relatively meager degradation of less than 10% in the system without CoV-POMs, in which CoV-POMs played a vital role to activate PMS towards free radicals generation for dye degradation. Methylene blue (MB) and rhodamine B (RB) dyes were completely decolorized under 60 min with the presence of 40 mg/L CoV-POMs and 150 mg/L PMS. The CoV-POMs/PMS system was pH dependance with a lower dye degradation efficiency at elevated pH. The effect of pH was more prominent in RB dye, in which the degradation efficiency dropped drastically from 93.3% to 41.12% with the increase in the solution pH from 7 to 11. The quenching tests suggested that sulfate radicals were the dominant active species involving in the dye degradation reaction. Besides MB and RB dyes, CoV-POMs/PMS system also showed significant activity towards the degradation of phenol red (PR) and methyl orange (MO) dyes. In the biological test, CoV-POMs exhibited non-toxic behavior towards normal cells that reduced safety concern for the large-scale wastewater treatment application. In addition, the testing divulged the anticancer property of CoV-POMs with more than 35 % of A549 lung adenocarcinoma and MDA-MB-231 breast adenocarcinoma were killed with 250 mg/L CoV-POMs. The selective lethality of CoV-POMs towards cancer cells was found to be caused by different extents of cellular apoptosis. In overall, the synthesized bifunctional CoV-POMs manifested superior activities in the examined applications, specifically dye degradation and anticancer. Ministry of Education (MOE) Submitted/Accepted version This work was financially supported by the Ministry of Education (MOE), Singapore (Grant No. RG102/18; Project ID. 2018-T1-001-077).

Tumor stromal residing cancer-associated fibroblasts (CAFs) are significant accomplices in the growth and development of malignant neoplasms. As cancer progresses, the stroma undergoes a dramatic remodeling and stiffening of its extracellular matrix (ECM). However, exactly how these biomechanical changes influence the CAF behavior and the functional paracrine crosstalk with the neighboring tumor cells in a 3-dimensional (3D) microenvironment remains elusive. Herein, a collagen and alginate interpenetrating network (CoAl-IPN) hydrogel system was employed as a 3D in vitro surrogate of the cancerous breast tissue stromal niche. In this study, the mechanical properties of CoAl-IPN were precisely fine-tuned with Young's modulus ( E) values of ∼108 and 898 Pa. The results revealed that the 3D polymeric network mechanics and microstructure are critical biophysical determinants of the human breast CAF (b-CAF) morphology, phenotype, and paracrine dialogue with MDA-MB-231 tumoroids. A compliant hydrogel network favors b-CAF spreading, nuclear translocation of the YAP/TAZ mechanosignaling protein, and upregulation of CAF hallmark transcripts. Conversely, a rigid and highly cross-linked hydrogel network imposed a physical entrapment effect on the b-CAFs that limited their spreading and phenotype in a manner that effectively muted their pro-tumorigenic paracrine activity. Collectively, the CoAl-IPN 3D culture system has proven to be a versatile platform in defining the 3D biophysical parameters that could either promote or restrain the protumorigenic activity of b-CAFs and sheds critical mechano-mediated light onto the phenotypic plasticity and corresponding specific bioactivity of b-CAFs in the 3D microenvironment.

Zinc oxide nanoparticles (Nano-ZnO) is currently one of the most extensively used inorganic particles in a wide range of skin care and consumable products. Therefore, examining the biological effects of Nano-ZnO, especially in the non-cytotoxic levels, thus holds important contemporary practical implications. Herein, our study demonstrates that long-term conditioning of human keratinocytes (HaCaTs) to non-cytoxic dose of Nano-ZnO (∼100 nm) can induce an adaptive response, leading to an enhancement of the cells tolerance against cytotoxic level of Nano-ZnO. It was found that the Nano-ZnO induced adaptive alteration is mediated by a strong synergism between the generation of reactive oxygen species (ROS) flares by a sub-population of cells that are loaded with Nano-ZnO and upregulation of several pro-inflammatory transcripts. Further studies revealed activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) stress response pathway and the associated downstream sustained augmented level of chymotrypsin-like 20 s proteasome activity to be the major mechanism underpinning this phenomenon. Interestingly, these cytoprotective responses can further aid the Nano-ZnO conditioned HaCaT cells to cross-adapt to harmful effects of ultraviolet-A (UVA) by reducing radiation-induced DNA damage. Our findings have unveiled a range of previously undocumented potent and exploitable bioeffects of Nano-ZnO induced ROS mediated signaling within the framework of nano-adaptation. MOE (Min. of Education, S’pore)

Vanadium dioxide (VO2) nanoparticles with reversible semiconductor-metal phase transition holds the tremendous potential as a thermochromic material for the energy-saving smart glazing. However, the trade-off between improving the luminous transmittance (Tlum) while sacrificing the solar modulation ability (ΔTsol) hampers its bench-to-market translation. Previous studies of anti-reflection coatings (ARCs) focused primarily on increasing Tlum while neglecting ΔTsol, which is a key energy-saving determinant. The intrinsically low ΔTsol (

Bioengineered extracellular matrix (ECM) mimetic materials have tunable properties and can be engineered to elicit desirable cellular responses for wound repair and tissue regeneration. By incorporating relevant cell-instructive domains, bioengineered ECM mimics can be designed to provide well-defined ECM-specific cues to influence cell motility and differentiation. More importantly, bioengineered ECM surfaces are ideal platforms for studying cell-material interactions without the need to genetically alter the cells. Here, we showed that bioengineered ECM mimics can be employed to clarify the role of integrins in keratinocyte migration. Particularly, the roles of α5β1 and α3β1 in keratinocytes were examined, given their known importance in keratinocyte motility. Two recombinant proteins were constructed; each protein contains a functional domain taken from fibronectin (FN-mimic) and laminin-332 (LN-mimic), designed to bind α5β1 and α3β1, respectively. We examined how patient-derived primary human keratinocytes migrate when sparsely seeded as well as when allowed to move collectively. We found, consistently, that FN-mimic promoted cell migration while the LN-mimic did not support cell motility. We showed that, when keratinocytes utilize α5β1 integrins on FN-mimics, they were able to form stable focal adhesion plaques and stabilized lamellipodia. On the other hand, keratinocytes on LN-mimic utilized primarily α3β1 integrins for migration and, strikingly, cells were unable to activate Rac1 and form stable focal adhesion plaques. Taken together, employment of our bioengineered mimics has allowed us to clarify the roles of α5β1 and α3β1 integrins in keratinocyte migration, as well as further provided a mechanistic explanation for their differences.

The endothelium presents a formidable barrier for cancer nanomedicine, as the intravenously introduced nanomedicine needs to leave the blood vessel at the tumor site. Endothelial permeability and retention effect (EPR) is not dependable since it is derived from tumors. Certain nanoparticles with specific characteristics are able to induce micrometer sized gaps between endothelial cells. This effect is called "nanoparticle induced endothelial leakiness" (NanoEL). NanoEL therefore allows the nanotechnology to control access to the tumor even in the absence of any EPR effect. Morever, NanoEL can be applicable to noncancer issues, thereby expanding its usefulness in other subfields of nanomedicine. In this paper, we have shown that Gold (Au) nanoparticles within the range of 10-30 nm are good NanoEL inducing particles. As not all endothelial cells have the same permeability, we found that human mammary endothelial cells and human skin endothelial cells are sensitive to Au induced NanoEL, while human umbilical vein endothelial cells are insensitive, reflective of their innate nature of endothelial permeability. The size window and endothelial cell type sensitivity then helps the nanotechnologists to design future nanoparticles that either exploit NanoEL as a nanotechnology driven strategy to access immature tumors, which do not induce the EPR effect, or avoid NanoEL as a nanotoxic side effect.

The integrity of the vasculature system is intrinsically sensitive to a short list of biophysical cues spanning from nano to micro scales. We have earlier found that certain nanomaterials could induce endothelial leakiness (nanoparticle induced endothelial leakiness, nanoEL). In this study, we report that the density of the nanomaterial, a basic intrinsic material property not implicated in many nanoparticle-mediated biological effects, predominantly dictates the nanoEL effect. We demonstrated that the impinging force exerted by a library of increasing effective densities but consistently sized silica nanoparticles (SiNPs) could directly increase endothelial permeability. The crossover effective particle density that induced nanoEL was determined to be between 1.57 g/cm3 to 1.72 g/cm3. It was also found that a cumulative gravitational-mediated force of around 1.8 nN/μm along the boundaries of the vascular endothelial cadherin (VE-cad) adherens junctions appeared to be a critical threshold force required t...

Tumor suppressive microRNAs are potent molecules that might cure cancer, one day. Despite the many advanced strategies for delivery of these microRNAs to the cell, there are few therapeutic microRNAs in clinical use. Progress in microRNA bioapplications is hindered by a high vulnerability of exogeneous microRNA molecules to RNase degradation that occurs in extra- and intracellular physiological conditions. In this proof-of-concept study, we use a programmable self-assembled DNA nanostructure bearing a “shuriken” shape to not only deliver but more importantly protect a tumor suppressive microRNA-145 for a sufficiently long time to exert its therapeutic effect in human colorectal cancer cells. Our DNA nanostructure harbored complementary sequences that can hybridize with the microRNA cargo. This brings the microRNA–DNA duplex very close to the core structure such that the microRNA cargo becomes sterically shielded from RNase's degradative activity. Our novel DNA nanostructure based protector concept removes the degradative bottleneck that may plague other nucleic acid delivery strategies and presents a new paradigm towards exploiting these microRNAs for anti-cancer therapy. Published version

Hypoxia is an environmental cue that is associated with multiple tumorigenic processes such as immunosuppression, angiogenesis, cancer invasion, metastasis, drug resistance, and poor clinical outcomes. When facing hypoxic stress, cells initiate several adaptive responses such as cell cycle arrest to reduce excessive oxygen consumption and co-activation of oncogenic factors. In order to identify the critical novel proteins for hypoxia responses, we used pulsed-SILAC method to trace the active cellular translation events in A431 cells. Proteomic discovery data and biochemical assays showed that cancer cells selectively activate key glycolytic enzymes and novel ER-stress markers, while protein synthesis is severely suppressed. Interestingly, deprivation of oxygen affected the expression of various epigenetic regulators such as histone demethylases and NuRD (nucleosome remodeling and deacetylase) complex in A431 cells. In addition, we identified PHF14 (the plant homeodomain finger-14) as a novel hypoxia-sensitive epigenetic regulator that plays a key role in cell cycle progress and protein synthesis. Hypoxia-mediated inhibition of PHF14 was associated with increase of key cell cycle inhibitors, p14ARF, p15INK4b, and p16INK4a, which are responsible for G1-S phase transition and decrease of AKT-mTOR-4E-BP1/pS6K signaling pathway, a master regulator of protein synthesis, in response to environmental cues. Analysis of TCGA colon cancer (n=461) and skin cancer (n=470) datasets revealed a positive correlation between PHF14 expression and protein translation initiation factors, eIF4E, eIF4B, and RPS6. Significance of PHF14 gene was further demonstrated by in vivo mouse xenograft model using PHF14 KD cell lines. Ministry of Education (MOE) National Medical Research Council (NMRC) Published version This study was supported by the Singapore Ministry of Education (MOE2014-T2-2-043, MOE2016-T2-2-018 and MOE2016-T3-1-003) and the National Medical Research Council of Singapore (NMRC-OF-IRG-0003-2016).

3D cellular spheroids/microcarriers (100 µm-1 mm) are widely used in biomanufacturing, and non-invasive biosensors are useful to monitor cell quality in bioprocesses. In this work, a novel microfluidic approach for label-free and continuous-flow monitoring of single spheroid/microcarrier (hydrogel and Cytodex) based on electrical impedance spectroscopy using co-planar Field's metal electrodes is reported. Through numerical simulation and experimental validation, two unique impedance signatures (|ZLF | (60 kHz), |ZHF | (1 MHz)) which are optimal for spheroid growth and viability monitoring are identified. Using a closed-loop recirculation system, it is demonstrated that |ZLF | increases with breast cancer (MCF-7) spheroid biomass, while higher opacity (impedance ratio |ZHF |/|ZLF |) indicates cell death due to compromised cell membrane. Anti-cancer drug (paclitaxel)-treated spheroids also exhibit lower |ZLF | with increased cell dissociation. Interestingly, impedance characterization of adipose-derived mesenchymal stem cell differentiation on Cytodex microcarriers reveals that adipogenic cells (higher intracellular lipid content) exhibit higher impedance than osteogenic cells (more conductive due to calcium ions) for both microcarriers and single cell level. Taken together, the developed platform offers great versatility for multi-parametric analysis of spheroids/microcarriers at high throughput (≈1 particle/s), and can be readily integrated into bioreactors for long-term and remote monitoring of biomass and cell quality.

The recent progresses in tissue engineering and nanomaterial-based therapeutics/theranostics have led to the ever increasing utilization of 3D in vitro experimental models as the bona fide culture systems to evaluate the therapeutic/theranostic effects of nanomedicine. Compared to the use of conventional 2D culture platforms, 3D biomimetic cultures offer unmatched advantages as relevant physiological and pathological elements can be incorporated to allow better characterization of the engineered bio-nanomaterials in the targeted tissue-specific microenvironment. In this Feature Article, the current state-of-the-art 3D in vitro models that have been developed for the evaluation of biosafety and efficacy of nano- therapeutics/theranostics targeting the colon, blood–brain barrier (BBB), lungs, skin tumor models to bridge the nanomedicine bench to pre-clinical ravine are reviewed. Furthermore, the critical physicochemical parameters of the bio-nanomaterials that govern its transport and biodistribution in a complex 3D microenvironment will be highlighted. The major challenges and future prospects of evaluating nanomedicine in the third dimension will also be discussed.

Exogenous sources of amino acids are essential nutrients to fuel cancer growth. Here, the increased demand for amino acid displayed by cancer cells is unconventionally exploited as a design principle to replete cancer cells with apoptosis inducing nanoscopic porous amino acid mimics (Nano-PAAM). A small library consisting of nine essential amino acids nanoconjugates (30 nm) are synthesized, and the in vitro anticancer activity is evaluated. Among the Nano-PAAMs, l-phenylalanine functionalized Nano-PAAM (Nano-pPAAM) has emerged as a novel nanotherapeutics with excellent intrinsic anticancer and cancer-selective properties. The therapeutic efficacy of Nano-pPAAM against a panel of human breast, gastric, and skin cancer cells could be ascribed to the specific targeting of the overexpressed human large neutral amino acid transporter SLC7A5 (LAT-1) in cancer cells, and its intracellular reactive oxygen species (ROS) inducing properties of the nanoporous core. At the mechanistic level, it is revealed that Nano-pPAAM could activate both the extrinsic and intrinsic apoptosis pathways to exert a potent "double-whammy" anticancer effect. The potential clinical utility of Nano-pPAAM is further investigated using an MDA-MB-231 xenograft in NOD scid gamma mice, where an overall suppression of tumor growth by 60% is achieved without the aid of any drugs or application of external stimuli. Nanyang Technological University The authors gratefully acknowledge the financial support from the Nanyang Technological University NTU-Harvard School of Public Health Initiative for Sustainable Nanotechnology (NTU-Harvard SusNano) Program (NTU-HSPH 18002 to C.Y.T.).

Exposure to inhaled anthropogenic nanomaterials (NM) with dimension

Background: Nitric oxide (NO) plays important regulatory roles in a plethora of biological functions and thus holds tremendous potential to be exploited for clinical uses. However, the chemistries in the molecular design of nano-nitric oxide delivery systems is currently lacking. Objective: The overarching aim of this review is to provide the readers with the fundamentals that relate to the design of NO release molecules (NORMs), loading and releasing mechanism, as well as delivery of NORMs for nanotherapeutics. Methods: We conducted a thorough literature search on the design and synthesis of NORMs, as well as the current state-of-the-art NO compatible delivery platforms to address various clinical needs. Results: N-diazeniumdiolate and S-nitrosothiol based NO molecules are among the most widely used NORMs for anti-cancer and anti-microbial applications. The innovative integration of these NORMs with cytocompatible organic and inorganic nanocarriers enabled controlled spatiotemporal delivery and release of NO at the targeted diseased sites. Conclusion: We have provided a comprehensive summary of the fundamental chemistries underpinning the molecular design of the NORMs and critically assessed the recent advancements of nano-NO delivery systems for advanced biomedical applications.

While matter at the nanoscale can be manipulated, the knowledge of the interactions between these nanoproducts and the biological systems remained relatively laggard. Current nanobiology study is rooted on in vitro study using conventional 2D cell culture model. A typical study employs monolayer cell culture that simplifies the real context of which to measure any nanomaterial effect; unfortunately, this simplification also demonstrated the limitations of 2D cell culture in predicting the actual biological response of some tissues. In fact, some of the characteristics of tissue such as spatial arrangement of cells and cell-cell interaction, which are simplified in 2D cell culture model, play important roles in how cells respond to a stimulus. To more accurately recapitulate the features and microenvironment of tissue for nanotoxicity assessments, an improved organotypic-like in vitro multicell culture system to mimic the kidney endoepithelial bilayer is introduced. Results showed that important nano-related parameters such as the diffusion, direct and indirect toxic effects of ZnO nanoparticles can be studied by combining this endoepithelial bilayer tissue model and traditional monolayer culture setting.

A polymer-based nanocarrier was developed for the co-delivery of epigenetic and chemotherapeutic drugs. The sterically stabilized hybrid micelle system uses micelles composed of D-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS or TPGS) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG2000). In this study, suberoylanilide hydroxamic acid (SAHA) and paclitaxel were used as model drugs for combination chemotherapy to enhance therapeutic efficiency in targeting mesenchyme-like triple negative breast cancer (TNBC) cells. Combination therapy of paclitaxel and SAHA in a dual drug micelle system, (P + S)mic, exhibited an IC50 value of 0.52 μg/mL, which is about 5.91-fold more cytotoxic than the mere combination of free drugs (P + S). Furthermore, the (P + S)mic formulation was far more effective at inhibiting cell migration by more than 3.4-fold than the control. Thus, our findings show that the co-delivery of these drugs using the micelle system greatly enhances their therapeutic effect at a lower dosage, thereby minimizing toxicity. In addition, this formulation is proved to be remarkably effective in preventing cell migration at low dosage.