Long-Term Tracking and Dynamically Quantifying of Reversible Changes of Extracellular Ca in Multiple Brain Regions of Freely Moving Animals.

Understanding physiological and pathological processes in the brain requires tracking the reversible changes in chemical signals with long-term stability. We developed a new anti-biofouling microfiber array to real-time quantify extracellular Ca concentrations together with neuron activity across many regions in the mammalian brain for 60 days, in which the signal degradation was < ca. 8 %. The microarray with high tempo-spatial resolution (ca. 10 μm, ca. 1.3 s) was implanted into 7 brain regions of free-moving mice to monitor reversible changes of extracellular Ca upon ischemia-reperfusion processes. The changing sequence and rate of Ca in 7 brain regions were different during the stroke. ROS scavenger could protect Ca influx and neuronal activity after stroke, suggesting the significant influence of ROS on Ca overload and neuron death. We demonstrated this microarray is a versatile tool for investigating brain dynamic during pathological processes and drug treatment.