On-site multiplex biosensors for innate immunity antibodies are ideal tools for monitoring health status of individuals against various diseases. This study introduces a novel antibody immunoassay testing platform incorporating microfiber-based arrays of antigens to capture specific antibodies. The fabrication and setup of the device revolved around electrospun polystyrene (ESPS) microfibers that act as three-dimensional membrane filters, capable of rapid and multifold analyte capture. In particular, the ESPS microfibers were patterned through localized oxygen plasma to create hydrophilic zones that facilitate fluid flows and immobilizations of antigens. The bulk of this robust antibody immunoassay platform could be installed into a compact syringedriven cassette device, which could perform multiplex antibody immunoassay for antibodies specifically against Middle East respiratory syndrome coronavirus (MERS-CoV) with rapid preparation amounting to a total of 5 min, as well as high sensitivity and specificity for the MERS-CoV down to 200 μg/mL.

This study investigated the fabrication and proof of concept design demonstrating rapid and highly sensitive antigen capture utilizing electrospun polystyrene (PS) microfiber mat substrates paired with vacuum pump pressurization to induce bulk flow. In comparison with conventional flat PS surfaces used for immunoassay purposes, this system optimizes the increased surface area of the electrospun polystyrene (ESPS) fiber mat substrates and the accelerated propagation of the antigen through the detection platform by using a vacuum pump to enable efficient and rapid antigen capture. The novelty of this work was demonstrated through a parametric study detailing how a fiber substrate can capture antigen sensitively and at high speeds. In terms of sensitivity, the current system is comparable to the conventionally used flat PS substrates. Additionally, the amount of antigen captured on a flat PS substrate in 60 minutes was surpassed in under 5 seconds when utilizing the ESPS-vacuum system. Three-dimensional ESPS fiber mats were then noted as a comparison between Damkohler numbers and between flat PS and ESPS-vacuum systems. The bulk flow of the ESPS-vacuum system allows for a Damkohler number of 0.37 indicating a balance between the flow rate and the reaction rate as opposed to a PS flat platform of 5.80 × 10 which illustrates a diffusion rate limited system. Finally, the overall ESPS-vacuum system was tested for its immunoassay capability. A sandwich fluorescence-based immunoassay was performed on both PS flat-diffusion and ESPS-vacuum systems. The ESPS-vacuum system indicated a wider detection range capability from 5 to 1000 ng mL in comparison with the PS flat-diffusion system at 5 to 100 ng mL.

Biosensing devices such as assays require both speed and sensitivity as two integral components for its effectiveness. Within this review, developed three-dimensional (3D) microfiber polystyrene (PS) platforms are leveraged to introduce a means for effectively rapid and sensitive assays. Considered broadly, the 3D structure contributes to an increased surface area for antibody immobilization while the natural hydrophobic nature of PS promotes this immobilization for immunoassay diagnostics. More specifically, rapid antigen capture can be realized by combining this platform with vacuum pressure to mitigate diffusion limitations for antibody-antigen interactions. Alternatively, the increased antibody immobilization density can realize the selective capture and release of circulating tumor cells (CTC). Through both low concentration CTC capture and effective release of said cells, patient-specific cancer care can be achieved.

Correction for 'Fabrication and assessment of an electrospun polymeric microfiber-based platform under bulk flow conditions with rapid and efficient antigen capture' by Carlton F. O. Hoy et al., Analyst, 2018, 143, 865-873.