Morphological characteristics of polymeric nylon‐6 film as biological recognition interface for electrochemical immunosensor application

The present study elucidates the morphology characteristic of nylon‐6 as protein immobilization film and their influences in biological recognition interface for a single‐use electrochemical immunosensor. A basic requirement of this polymer platform is to allow the testing analyte [conductive polyaniline‐Fe 2 O 3 ‐glutaraldehyde‐conjugated‐ N ‐hydroxysuccinimidobiotin (PANI‐Fe 2 O 3 ‐GA‐b‐NHS)] to access to the immobilized capture reagent [bovine serum albumin (BSA)] on a surface of the nylon‐6 film. As an immunoassay, the biochemical reaction between PANI‐Fe 2 O 3 ‐GA‐b‐NHS and BSA takes place on a surface of the nylon‐6 support film, which then translated into measurable resistance signal through pulse‐mode measurement. The in‐house developed nylon‐6 film, N‐16B, with 16 wt % nylon polymer and methanol as nonsolvent had demonstrated the fastest lateral wicking speed (1.07 mm s −1 ) and excellent protein immobilization capacity (1650 ± 85.84 μg cm −3 ), leading to the higher electrical current signal with a minimal resistance of electrochemical responses (0.57 ± 0.04 MΩ). This work reflects the importance of the physical characteristics of the nylon‐6 film that determines the sensitivity and effectiveness of an immunosensor. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46741.