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Background Biosensors are an emerging field in biomedical diagnostics. In the field of biosensors, field-effect transistor (FET)-based biosensors are widely used in clinical, environmental, and food analysis fields because of their high sensitivity, specificity, and real-time detection. Matrix metallopeptidase 9 (MMP9) is a gene closely related to various diseases, which is considered to have a predictive role in disease diagnosis and qualitative treatment. Methods In this study, an all-solid-state, ultrasensitive FET biosensor based on monolayer molybdenum disulfide (MoS2) was designed and constructed. We synthesized a series of MMP9-targeted probes and obtained the optimal hybridization conditions (including optimal hybridization temperature, hybridization concentration, and hybridization time) for the MoS2 FET biosensors. Results The data show that this MoS2 FET biosensor detects the MMP9 gene at a minimum of 3.86 pM with promising selectivity, specificity, and reproducibility. Conclusion The MoS2 FET biosensor detects the MMP9 gene at a minimum of 3.86 pM with promising selectivity, specificity, and reproducibility. Our work not only provides a potential strategy for the diagnosis and treatment of MMP9-related diseases, but also is helpful for the design of nanodevices, the development of portable diagnostic devices, and the implementation of personalized medicine.

Light addressable potentiometric sensor (LAPS) with the structure of electrolyte-insulator-semiconductor is a kind of field effect sensor that detects local potential changes caused by protonation and deprotonation between electrolyte and insulator by light pulse. And scanned light pulse allows two-dimensional imaging of the distribution of chemical/biological species on the surface of sensor. An important challenge is to achieve low-cost, strong anti-interference and high-performance silicon-based LAPS. In this study, we propose to combine microsphere lithography with wet etching to fabricate well-ordered, tunable and low-cost pyramidal pits-patterned silicon as semiconductor of LAPS. The morphology and optical properties of pyramidal pits-patterned silicon are tested and analyzed. The sensing characteristics and the pH imaging performance of LAPS are tested and evaluated. The experiment results and theoretical analyses show that LAPS with pyramidal pits-patterned silicon has acceptable pH response, good long-term stability, and high performance in terms of photocurrent enhancement ratio, signal-to-noise ratio and pH imaging. This work can provide a simple, low-cost, strong anti-interference and high-performance device for pH-related chemical/biological analysis.

With the rapid breakthrough of electrochemical treatment of tumors, electric field (EF)-sensitive genes, previously rarely exploited, have become an emerging field recently. Here, we reported our work for the identification of EF-sensitive genes in lung cancer cells. The gene expression profile (GSE33845), in which the human lung cancer CL1-0 cells were treated with a direct current electric field (dcEF) (300 mV/mm) for 2 h, was retrieved from GEO database. Differentially expressed genes (DEGs) were acquired, followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) and protein-protein interaction (PPI) analysis. Hub genes were acquired and analyzed by various tools including the Human Protein Atlas, Kaplan-Meier analysis, Cytoscape, FunRich, Oncomine and cBioPortal. Subsequently, three-dimensional protein models of hub genes were modeled by Modeller 9.20 and Rosetta 3.9. Finally, a 100 ns molecular dynamics simulation for each hub protein was performed with GROMACS 2018.2. A total of 257 DEGs were acquired and analyzed by GO, KEGG and PPI. Then, 10 hub genes were obtained, and the signal pathway analysis showed that two inflammatory pathways were activated: the FoxO signaling pathway and the AGE-RAGE signaling pathway. The molecular dynamic analysis including RMSD and the radius of gyration hinted that the 3D structures of hub proteins were built. Overall, our work identified EF-sensitive genes in lung cancer cells and identified that the inflammatory state of tumor cells may be involved in the feedback mechanism of lung cancer cells in response to electric field stimulation. In addition, qualified three-dimensional protein models of hub genes were also constructed, which will be helpful in understanding the complex effects of dcEF on human lung cancer CL1-0 cells.

The chemical image sensor has attracted much attention because of its ability to visualize the spatial distribution of biochemical species in solution. However, the lateral diffusion of photo-generated carriers generated by illuminating backside of the substrate limits the spatial resolution of the sensor and the sharpness of the image. In this study, honeycomb meshed metal array based on microsphere lithography as working electrodes of the sensor is proposed. A focused light spot illuminates a plurality of periodic and ordered mesh holes and the metal electrodes adjacent to the mesh holes. For chemical imaging performance, sensors with honeycomb meshed working electrodes are developed for comparison with the sensor the flat working electrodes, and their spatial resolution is tested under the focused light spot with different sizes. Three interpretations of improved spatial resolution including enhanced recombination of the photo-generated holes by electrons during the initial stage of lateral diffusion and two boundary cases of modulated light illuminating meshed working electrodes on the substrate are elaborated. The experimental results show that the spatial resolution of sensor chips with honeycomb meshed working electrodes is better than that of the sensor with the flat working electrodes and is higher under the illumination condition of smaller light spots.

Light addressable potentiometric sensor (LAPS) is a flexible addressable potential sensor with many advantages including simple structure, high sensitivity, low manufacturing cost and light addressability. It can help us to achieve a high performance and low cost of LAPS to combine well-ordered polystyrene (PS) colloidal monolayer with fabricating of LAPS. This paper presents an alcohol-assisted interfacial fabrication method for fabricating low-cost, large-scale and well-ordered PS colloidal monolayer for LAPS in a simple laboratory. The effects of dispersants on PS colloidal self-assembly monolayer are investigated. The mechanism of well-ordered PS colloidal monolayer fabricated with methyl alcohol as the dispersant and the mechanism of disordered PS colloidal monolayer fabricated with ethyl alcohol as the dispersant are described in detail. The PS colloidal monolayer as a template, is used in fabrication of honeycomb meshed array working electrode to optimize performance of LAPS. Moreover, it is proved that the area ratio of the honeycomb meshed array to the silicon substrate is a constant which is independent of the diameter of the PS colloidal sphere. LAPS with honeycomb meshed array has an acceptable sensitivity of 53.47 mV/pH and high linearity of 99.8% in the measurement of pH. The change of photocurrent is also compared deeply for optimization. The results show that LAPS with honeycomb meshed array can reduce signal crosstalk between the detection points and improve addressability of LAPS.

Recently, nanosecond pulsed electric field (nsPEF) has been considered as a new tool for tumor therapy, but its molecular mechanism of function remains to be fully elucidated. Here, we explored the cellular processes of Jurkat cells exposed to nanosecond pulsed electric field. Differentially expressed genes (DEGs) were acquired from the GEO2R, followed by analysis with a series of bioinformatics tools. Subsequently, 3D protein models of hub genes were modeled by Modeller 9.21 and Rosetta 3.9. Then, a 100 ns molecular dynamics simulation for each hub protein was performed with GROMACS 2018.2. Finally, three kinds of nsPEF voltages (0.01, 0.05, and 0.5 mV/mm) were used to simulate the molecular dynamics of hub proteins for 100 ns. A total of 1769 DEGs and eight hub genes were obtained. Molecular dynamic analysis, including root mean square deviation (RMSD), root mean square fluctuation (RMSF), and the Rg, demonstrated that the 3D structure of hub proteins was built, and the structural characteristics of hub proteins under different nsPEFs were acquired. In conclusion, we explored the effect of nsPEF on Jurkat cell signaling pathway from the perspective of molecular informatics, which will be helpful in understanding the complex effects of nsPEF on acute T-cell leukemia Jurkat cells.