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Metabolic syndrome, a collection of metabolic abnormalities including diabetes and obesity, affects hundreds of millions of people, and poses a major financial burden to public healthcare around the world. There are two major types of diabetes: Type-1, which is caused by a lack of insulin production and Type-2, which results from a relative deficiency of insulin secretion. Electrical activity of various ion channels in beta (β)-cells plays an important role in the stimulus-secretion of insulin in Type-2 diabetes. Here, we utilize a silicon based lateral patch clamp device to conduct whole cell patch clamp measurements in insulin secreting rat insulinoma (INS-1) cells. High gigaohm seals were achieved between the microfabricated glass capillary apertures and INS-1 cells resulting in picoampere current recordings from various potassium and calcium ion channels. Steady state I–V plots elicited characteristic ion channel properties and longevity of the whole cell mode could be maintained for 1 h without any breakage of the gigaohm seal. Glucose dose responses were also recorded and showed proportional current responses in voltage gated potassium channels. Delivery of multiple ion channel blockers (sulfonylurea drugs) resulted in suppression of currents in potassium channels. The results showcase the capability of our device in performing whole cell measurements and pave a way for developing a cheap platform using our silicon based approach.

The natural state of the interior of a living cell is extremely dense with numerous molecules packed into a tiny amount of space. Such a physiological environment is known as “crowded” and can exert profound effects on the thermodynamic and kinetic properties of the molecules. In general most biochemical experiments involve low molecular concentrations and in the process, underestimate many reaction rates. This paper reports work on a microfluidic system fabricated using polydimethylsiloxane, and relied on chaotic advection to rapidly mix crowded biological solutions that have been isolated in droplets (slugs). By forcing the slugs through a pillar matrix, the slugs were compelled to stretch and fold repeatedly, creating unsteady fluid flows that rapidly mixed the slug contents in tens of milliseconds at Reynolds number in the order of 10−3. Both straight and serpentine channels containing pillars were used for mixing the slug contents. Our results suggested that the pillars generated a significant amount of interfacial stresses on the slugs and in the process induced rapid mixing. This makes the system suitable for the study of reaction kinetics, which requires reactants to be mixed faster than the actual reaction time itself.