Rapid prototyping of multifunctional microfluidic cartridges for electrochemical biosensing platforms

A multifunctional microfluidic cartridge for electrochemical biosensing (μCEB) was developed with a cleanroom-free rapid prototyping technique. A seven-layered μCEB platform including a gold (Au) electrode substrate was fabricated by alternating patterned thin plastic and adhesive films. To provide conformal bonding between layers, pressure sensitive adhesive (PSA) tape was adopted to fabricate a leak-free, porous membranes embedded μCEB platform compatible with relatively high flow rates. In addition, the embedded porous membranes provide multiple functions in the μCEB device, including (1) controlling fluid flow, (2) storing a dried detergent, and (3) trapping liquid waste. To demonstrate the utility of the μCEB, we performed an electrochemical-based immunoassay to detect various concentrations of Creatine Kinase (CK)-Myocardial Band (MB). During the immunoassay, the membranes controlled the flow path to minimize a carryover between the assay steps and released the stored dried-reagent to remove non-specifically bound detection antibodies. With a linear sweep voltammetry (LSV) electrochemical sensing technique, a limit of detection of 0.25 ng mL^-1 was achieved. The multilayered prototyping technique enables rapid and low-cost fabrication of multifunctional microfluidic electrochemical devices with single-use sample processing components.