Responsive Janus Structural Color Hydrogel Micromotors for Label-Free Multiplex Assays

Micromotors with self-propelling ability demonstrate great values in highly sensitive analysis.Developing novel micromotors to achieve label-free multiplex assay is particularly intriguing in terms of detection efficiency.Herein,structural color micromotors(SCMs)were developed and employed for this purpose.The SCMs were derived from phase separation of droplet templates and exhibited a Janus structure with two distinct sections,including one with structural colors and the other providing catalytic selfpropelling functions.Besides,the SCMs were functionalized with ion-responsive aptamers,through which the interaction between the ions and aptamers resulted in the shift of the intrinsic color of the SCMs.It was demonstrated that the SCMs could realize multiplex label-free detection of ions based on their optical coding capacity and responsive behaviors.Moreover,the detection sensitivity was greatly improved benefiting from the autonomous motion of the SCMs which enhanced the ion-aptamer interactions.We anticipate that the SCMs can significantly promote the development of multiplex assay and biomedical fields.