No abstract

Resisting biomolecule adsorption onto the surface of brain-implanted microelectrodes is a key issue for in vivo monitoring of neurochemicals. Herein, we demonstrate that an ultrathin cell-membrane-mimic film of ethylenedioxythiophene tailored with zwitterionic phosphorylcholine (EDOT-PC) electropolymerized onto the surface of a carbon fiber microelectrode (CFE) not only resists protein adsorption but also maintains the sensitivity and time response for in vivo monitoring of dopamine (DA). As a consequence, the as-prepared PEDOT-PC/CFEs could be used as a new reliable platform for tracking DA in vivo and would help understand the physiological and pathological functions of DA.

In vivo electrochemistry is one powerful strategy for probing brain chemistry. However, the decreases in sensitivity mainly caused by the adsorption of proteins onto electrode surface in short-term in vivo measurements unfortunately render great challenges in both electrode calibration and selectivity against the alternation of proteins. In this study, we observe that the pretreatment of carbon fiber microelectrodes (CFEs) with bovine serum albumin (BSA) would offer a simple but effective strategy to the challenges mentioned above. We verify our strategy for dopamine (DA) with conventionally used CFEs and for ascorbate with our previously developed carbon nanotube-modified CFEs. We find that, in artificial cerebral spinal fluid (aCSF) solution containing BSA, the current responses of the microelectrodes equilibrate shortly and the results for precalibration carried out in this solution are found to be almost the same as those for the postcalibration in pure aCSF. This observation offers a new solution to electrode calibration for in vivo measurements with a technical simplicity. Furthermore, we find that the use of BSA pretreated CFEs to replace bare CFEs would minimize the interference from the alternation of proteins in the brain. This study offers a new general and effective approach to in vivo electrochemistry with a high reliability and a simplified procedure.