Numerical simulations were applied to guide the design of a gut-on-a-chip device with controllable oxygen gradients. Bifidobacterium bifidum was demonstrated to increase the stability of the intestinal epithelial barrier on the disease model.

In pharmaceutical research and development, improving the effectiveness of preclinical predictions is significant, thus in vitro and in vivo experimental models are needed to investigate human drug responses in organisms. As a microengineered model, an organ-on-a-chip (OoC) could provide reliable predictions of drug efficacy and safety by mimicking the complex biological functions of normal cellular interactions. It presents a novel platform with the advantages of high throughputs, low cost, and high efficiency for drug development. Here, we provide an outlook on the recent fundamental development of OoC studies and discuss the prospects of their applications in relation to drug discovery. In particular, we highlight a set of recently developed strategies that facilitate high-throughput analysis of biomarkers and drug metabolites on an OoC, including ELISA, PCR, LC-MS and lab-on-a-chip. A brief summary is also presented along with the prospects of this field in the future.

Integrating three-dimensional (3D) microelectrodes on microfluidic chips based on polydimethylsiloxane (PDMS) has been a challenge. This paper introduces a composite 3D electrode composed of Ag powder (particle size of 10 nm) and PDMS. Ethyl acetate is added as an auxiliary dispersant during the compounding process. A micromachining technique for processing 3D microelectrodes of any shape and size was developed to allow the electrodes to be firmly bonded to the PDMS chip. Through theoretical calculations, numerical simulations, and experimental verification, the role of the composite 3D microelectrodes in separating polystyrene particles of three different sizes via dielectrophoresis was systematically studied. This microfluidic device separated 20-, 10-, and 5-μm polystyrene particles nondestructively, efficiently, and accurately.

Spearmint (Mentha spicata L.) is normally used as a vegetable flavoring herb. It also has several pharmacological activities against fever, cough, infection, and inflammation. The current study presents an untargeted comparative metabolomics approach utilizing HPLC-QTOF-MS high-throughput analytical technology to provide insights into the effect of the drying process on the examined spearmint species. To the best of our knowledge, this is the first report of compositional differences among fresh and dried spearmint leaves determined via a metabolomic approach to reveal that dried leaves are a better source of bioactive metabolites. The nephrotoxicity of kaempferol, a bioactive metabolite from spearmint, was further assessed with a kidney-on-a-chip. On the designed chip, a GelMA-based 3D culture platform mimics the microenvironment and basic functions of the kidney. In addition, the chip’s transparency allows for direct observation under an optical microscope. Treatment of human embryonic kidney cells with 30 μM of kaempferol for 12 h induced no obvious cell injury or apoptosis in the cells, on the basis of morphology, thus providing a proof-of-concept demonstration of kaempferol’s non-toxicity.