A membrane-based immunosensor enabling high antifouling performance and sensitive molecular recognition

The fouling of non-targeted biomolecules on sensing surfaces, which can cause a reduction in sensing performance, is a severe problem in immunosensing platforms. The incorporation of hydrophilic polymers on sensing surfaces is effective against antifouling. However, such an approach can reduce the density of the capture antibody, resulting in a decrease in sensitivity and signal output. Here, both high sensitivity and antifouling properties were achieved using a porous-membrane-based immunosensor. This sensor can drastically mitigate the signal reduction due to the introduction of an antifouling moiety by antibody densification in submicron-scaled pores. The ideal ratio of the receptor/antifouling moiety was estimated from numerical modeling. The high sensitivity and antifouling properties of the designed sensor were demonstrated via the detection test of interleukin-6 (IL-6). The proposed sensor exhibited excellent antifouling and high sensitivity with limits of detection of 4.8 and 1.2 pg mL^-1 in artificial saliva and serum, respectively. The study findings highlight the potential of membrane-based sensors for practical diagnoses.