Rapid purification and enrichment of viral particles using self-propelled micromotors

Virus infections remain one of the principal causes of morbidity and mortality worldwide. The current gold standard approach for diagnosing pathogens requires access to reverse transcription-polymerase chain reaction (RT-PCR) technology. However, separation and enrichment of the targets from complex and diluted samples remains a major challenge. In this work, we proposed a micromotor-based sample preparation concept for the efficient separation and concentration of target viral particles before PCR. The micromotors are functionalized with antibodies with a 3D polymer linker and are capable of self-propulsion by the catalytic generation of oxygen bubbles for selective and positive virus enrichment. This strategy significantly improves the enrichment efficiency and recovery rate of virus (up to 80% at 10⁴ tu mL^-1 in a 1 mL volume within just 6 min) without external mixing equipment. The method allows the C_t value in regular PCR tests to appear 6-7 cycles earlier and a detection limit of 1 tu mL^-1 for the target virus from swap samples. A point-of-need test kit is designed based on the micromotors which can be readily applied to pretreat a large volume of samples.