To summarize, the present study achieved detection sensitivity close to that of a commercial ELISA kit with no probe labeling and a much shorter processing time (e.g., a typical kit requires 1 h for EV capture and several hours of incubation for antibody reactions and subsequent enzyme reactions). The sensitivity of previous microfluidics-based systems, using RT-qPCR or aptamer-based fluorescent probes, is superior; however, our system has advantages in terms of simplicity and cost because it only requires a one-step procedure, no expensive reagents, a bright-field microscope with low magnification, and simple image processing. Thus, we believe that this system is suitable for situations where frequent measurements with relatively high sensitivity are needed, such as post-operative monitoring, monitoring of infectious diseases, and environmental monitoring. Furthermore, we expect that this VIF-based system will accelerate and enhance the detection sensitivity of other previously reported immuno-aggregation systems by inducing microscale local stirring to enhance aggregate formation. The VIF system provides a powerful option to the repertoire of NP detection methods using affinity capture principles.