Gel Electrophoresis Chip Using Joule Heat Self-Dissipation, Short Run Time, and Online Dynamic Imaging.

Gel electrophoresis (GE) is one of the most general tools in biomedicine. However, it suffers from low resolution, and its mechanism has not been fully revealed yet. Herein, we presented the dispersion model of w2 (t) ∝ Tt, showing the band dispersion (w) via temperature (T) and running time (t) control. Second, we designed an efficient GE chip via the time control and rapid Joule heat self-dissipation by thermal conductive plastic (TCP) and electrode buffer. Third, we conducted the simulations on TCP and polymethylmethacrylate (PMMA) chips, unveiling that (i) the temperature of TCP was lower than the PMMA one, (ii) the temperature uniformity of TCP was better than the PMMA one, and (iii) the resolution of TCP was superior to the PMMA one. Fourth, we designed both TCP and PMMA chips for experimentally validating the dispersion model, TCP chip, and simulations. Finally, we applied the TCP chip to thalassemia and model urine protein assays. The TCP chip has merits of high resolution, rapid run of 6-10 min, and low cost. This work paves the way for greatly improving electrophoretic techniques in gel, chip, and capillary via temperature and time control for biologic study, biopharma quality control, clinical diagnosis, and so on.

An"ON-OFF" switchable power output of enzymatic biofuel cell controlled by thermal-sensitive polymer.

A novel "ON-OFF" switchable enzymatic biofuel cell (EBFC), controlled by in situ thermal-stimuli signal, has been consciously designed. Poly (N-isopropylacrylamide) (PNIPAm) chains were used to act as "ON" and "OFF" channels. Consecutively switching of temperature below and above the lower critical solution temperature (LCST), the reversible conformation changing of the PNIPAm chains between superhydrophilicity and superhydrophobicity was achieved, which constructed the "ON" and "OFF" channel for the transfer of the electrochemical probe to the underlying electrode correspondingly. Gold nanoparticles (AuNPs) protected glucose oxidase and laccase were successfully entrapped into the intelligent thermal-sensitive PNIPAm chains, and performed as the catalysts for the oxidation of glucose and the reduction of O2, respectively. Below the LCST, the fuels and the mediator could access to the catalytic centers of enzymes (set as "ON" state); while above the LCST, the reaction was impeded because the process of reactant transmission was blocked (set as "OFF" state). By switching the "valve" of mass transfer, the fabricated EBFC displayed the obvious "ON-OFF" controllable behavior. At the "ON" state, the open circuit voltage (Ecell(ocv)) and maximal power output density (Pmax) could reach to 0.70 V and 20.52 µW cm(-2), respectively; while at the "OFF" state, the Ecell(ocv) and Pmax were only 0.30 V and 3.28 µW cm(-2) correspondingly. The switchable process was repeatable, and the response time was only several minutes.