RESUMO
The liquid-liquid interface offers a fascinating avenue for generating hierarchical compartments. Herein, the dynamic imine chemistry is employed at the oil-water interface to investigate the effect of dynamic covalent bonds for modulating the droplet shape. The imine bond formation between oil-soluble aromatic aldehydes and water-soluble polyethyleneimine greatly stabilized the oil-water interface by substantially lowering the interfacial tension. The successful jamming of imine-mediated assemblies was observed when a compressive force was applied to the droplet. Thus, the anisotropic compartmentalization of the liquid-liquid interface was created, and it was later altered by changing the pH of the surrounding environment. Finally, a proof-of-concept demonstration of a pH-triggered cargo release across the interfacial membrane confirmed the feasibility of stimuli-responsive behavior of dynamic imine assemblies.
RESUMO
In view to develop an autonomous lab-on-a-chip device for detection of toxins without using any spectroscopic or electrochemical equipment, self-powered enzyme micropumps were fabricated via layer-by-layer assembly of enzymes and polyelectrolytes. The thin film-based enzyme micropumps turned on fluid flow in the presence of respective substrates in a concentration-dependent manner, and the rate of the enzymatic reaction was the key for maneuvering the fluid flow. Furthermore, the newly engineered enzyme-based micropumps were able to detect toxic metals and organophosphorus pesticides by modulating the fluid flow speed as the rate of the enzymatic reaction was altered by the presence of inhibitors. Thus, by regulating fluid flow in a micropump, low concentrations of analytes (e.g., target biomarkers and inhibitors) in biological fluids can be quantitatively identified for testing in a resource-constrained environment.
