A compact, durable, low-reagent-usage, portable miniaturized electrochemical sensor is successfully developed for the high sensitivity detection of trace lead. We fabricated micropillars array working electrodes on the chip and established ultra-low concentration sodium acetate-acetate (NaAC-HAC) buffers (pH ≈ 4.5) system to enhance the detection sensitivity of the sensor. The ultra-low concentration buffer possesses unique features such as low baseline current and high peak current difference height. The analytical performance of the fabricated electrochemical sensor with 3D gold (Au) working electrodes modified by bismuth-film was comprehensively studied. The microsensor exhibited a high sensitivity of 0.0412 µ A ppb ⁻¹ and a satisfactory detection limit of 0.15 ppb when detecting lead ions under optimized conditions. Moreover, good linearity (correlation coefficient: 0.9993) with lead ion measurements in the concentration range of 1–120 ppb and excellent repeatability (RSD: 1.79%) was obtained, the chip has satisfactory selectivity for common interference ion. Besides, a low consumption of 350 µ l of reagents per test was acquired. Finally, the proposed microsensor was applied to detect trace metal ions in tap and lake samples with satisfactory results.

A microfluidic droplet platform based on flow resistance has been designed to generate, capture and analyze a single cell. In this device, a single cell was encapsulated in micro-droplet form and positioned precisely in arrays of sloped channels on a polydimethylsiloxane–glass chip. The droplets were formed at the ‘T-junction’ and trapped by the ‘main–bypass’ construction. The single cell capture efficiency was up to 60%. Besides, the device caused no harm to living cells as the microdroplet formed here provided a relatively stable micro-environment. The device had the advantages of reagent economy, passive driving, and minimal cell damage, making it a powerful tool for single-cell analysis.

Heatstroke (HS) is a life-threatening injury requiring neurocritical care which could lead to central nervous system dysfunction and severe multiple organ failure syndrome. The cell–cell adhesion and cell permeability are two key factors for characterizing HS. To investigate the process of HS, a biochip-based electrical model was proposed and applied to HS. During the process, the value of TEER is associated with cell permeability and C_I which represents cell–cell adhesion decreases that are consistent with the reduction in cell–cell adhesion and cell permeability characterized by proteins (occludin, VE-Cadherin and ZO-1) and RNA level. The results imply that the model can be used to monitor the biological process and other biomedical applications.