A microfluidic approach to studying the injection flow of concentrated albumin solutions

Subcutaneous injection by means of prefilled syringes allows patients to self-administrate high-concentration (100 g/L or more) protein-based drugs. Although the shear flow of concentrated globulins or monoclonal antibodies has been intensively studied and related to the injection force proper of SC processes, very small attention has been paid to the extensional behavior of this category of complex fluids. This work focuses on the flow of concentrated bovine serum albumin (BSA) solutions through a microfluidic "syringe-on-chip" contraction device which shares some similarities with the geometry of syringes used in SC self-injection. By comparing the velocity and pressure measurements in complex flow with rheometric shear measurements obtained by means of the "Rheo-chip" device, it is shown that the extensional viscosity plays an important role in the injection process of protinaceous drugs.

A microfluidic "syringe on chip" device mimicking the injection flow of protinaceous drugs has been developed.The velocity field of concentrated BSA solutions through the "syringe on chip" is Newtonian-like.The extensional viscosity of concentrated protein solutions should also be considered when computing injection forces through needles.