Fragmented Nanofibers with Bulky Aggregation Behavior for a Turbidimetric Immunoassay

Much attention has been paid to nonspherical polymer particles, which have hidden and intriguing properties compared to those of conventional spherical particles. Polymeric nanofibers are one type of nonspherical nanomaterial, but fabricating such nanofibers stably suspended in water and controlling their aggregation and dispersion properties remain a challenge. Herein, we propose a top-down method to fabricate nonspherical and fragmented nanofibers stably suspended in water. We use a simple procedure: (i) electrospinning of the polystyrene nanofibers, (ii) fragmentation by homogenizer, and (iii) surface modification of the fragmented nanofibers. Intriguingly, the fragmented nanofibers after precipitation were bulkily packed together, compared to spherical particles, due to their nonspherical shape and the stiffness derived from polystyrene. Using this unique property, we demonstrate that fragmented nanofibers with a bulky aggregation property can provide specific, visual, and highly sensitive detection of antigen. The fragmented nanofibers may be a candidate carrier for an alternative to a conventional latex turbidimetric immunoassay.