Microfluidic Biosensor Decorated with an Indium Phosphate Nanointerface for Attomolar Dopamine Detection

Developing functional materials that directly integrate into miniaturized devices for sensing applications is essential for constructing the next-generation point-of-care system. Although crystalline structure materials such as metal organic frameworks are attractive materials exhibiting promising potential for biosensing, their integration into miniaturized devices is limited. Dopamine (DA) is a major neurotransmitter released by dopaminergic neurons and has huge implications in neurodegenerative diseases. Integrated microfluidic biosensors capable of sensitive monitoring of DA from mass-limited samples is thus of significant importance. In this study, we developed and systematically characterized a microfluidic biosensor functionalized with the hybrid material composed of indium phosphate and polyaniline nanointerfaces for DA detection. Under the flowing operation, this biosensor displays a linear dynamic sensing range going from 10^-18 to 10^-11 M and a limit of detection (LOD) value of 1.83 × 10^-19 M. In addition to the high sensitivity, this microfluidic sensor showed good selectivity toward DA and high stability (>1000 cycles). Further, the reliability and practical utility of the microfluidic biosensor were demonstrated using the neuro-2A cells treated with the activator, promoter, and inhibiter. These promising results underscore the importance and potential of microfluidic biosensors integrated with hybrid materials as advanced biosensors systems.