Bionic radical-polymerization tailored nanofilm sensor for long-term in vivo monitoring ionic dynamics in cerebrospinal fluid

Abstract

Cerebrospinal fluid (CSF) plays a crucial role in maintaining central nervous system (CNS) function by regulating ionic homeostasis. Disruptions in CSF ionic strength are closely linked to the progression of neurological disorders such as Parkinson's disease (PD) and glioma. However, continuous in vivo monitoring of these ionic dynamics remains a major challenge due to limitations in existing sensing technologies. Inspired by the formation of neuromelanin, we present a flexible electrochemical sensor engineered via a one-step, mild co-polymerization with no residual organic solvents strategy that leverages dopamine-derived radicals to initiate the electrochemical polymerization of pyrrole. This process yields a conductive, hydrophilic, and biocompatible polydopamine-pyrrole composite layer optimized for stable interfacing with neural tissue. When applied in murine models of PD and glioma, the nanosensor enables long-term, real-time monitoring of CSF ionic fluctuations throughout disease progression. These results offer new insights into the pathophysiological roles of ionic imbalance and establish a robust platform for neurochemical monitoring with potential applications in early diagnosis and therapeutic development.