In vivo fast equilibrium microextraction by stable and biocompatible nanofiber membrane sandwiched in microfluidic device.

In vivo analysis poses higher requirements about the biocompatibility, selectivity and speed of analytical method. In this study, an in vivo fast equilibrium microextraction method was developed with a biocompatible core-sheath electrospun nanofiber membrane sandwiched within a microfluidic unit. The polystyrene/collagen core-sheath nanofiber membrane was coaxially electrospun and strengthened with in situ glutaraldehyde cross-linking. This membrane not only kept high mass transfer rate, large extraction capacity and biomatrix resistance as our previously proposed membrane (Anal. Chem. 2013, 85 (12), 5924-5932), but also got much better mechanical strength and stability in water. The microfluidic device was designed to sandwich the membrane, and the blood in vivo can be introduced into it and get contact with the membrane repetitively. With this membrane and device, a 2-min equilibrium in vivo extraction method was established, validated in a simulated blood circulation system, and was used to monitor the pharmacokinetic profiles of desipramine in rabbits. The free and total concentration of desipramine in vivo was monitored with 10-min interval almost without rabbit blood consumed. The results met well with those of in vitro extraction, and a correlation factor of 0.99 was obtained.