Development and Characterization of Electrodes Coated with Plasma-Synthesized Polypyrrole Doped with Iodine, Implanted in the Rat Brain Subthalamic Nucleus.

Biological treatments involve the application of metallic material coatings to enhance biocompatibility and properties. In invasive therapies, metallic electrodes are utilized, which are implanted in patients. One of these invasive therapeutic procedures is deep brain stimulation (DBS), an effective therapy for addressing the motor disorders observed in patients with Parkinson's disease (PD). This therapy involves the implantation of electrodes (IEs) into the subthalamic nucleus (STN). However, there is still a need for the optimization of these electrodes. Plasma-synthesized polypyrrole doped with iodine (PPPy/I) has been reported as a biocompatible and anti-inflammatory biomaterial that promotes nervous system regeneration. Given this information, the objective of the present study was to develop and characterize a PPPy/I-coated electrode for implantation into the STN. The characterization results indicate a uniform coating along the electrode, and physical-chemical characterization studies were conducted on the polymer. Subsequently, the IEs, both coated and uncoated with PPPy/I, were implanted into the STN of male rats of the Wistar strain to conduct an electrographic recording (EG-R) study. The results demonstrate that the IE coated with PPPy/I exhibited superior power and frequency signals over time compared to the uncoated IE (p < 0.05). Based on these findings, we conclude that an IE coated with PPPy/I has optimized functional performance, with enhanced integrity and superior signal quality compared to an uncoated IE. Therefore, we consider this a promising technological development that could significantly improve functional outcomes for patients undergoing invasive brain therapies.

Characterization of the sleep-wake cycle of the Neotropical rodent Proechimys guyannensis.

OBJECTIVES: To better understand the sleep-wake cycle characteristics in the female Neotropical rodent Proechimys guyannensis related to comparative neurobiology. METHODS: Surface neocortical and hippocampal electrodes were chronically implanted in the brains of female Wistar and Proechimys animals. In addition, electrodes for the study of muscle activity were implanted into the neck muscle of both species. After surgical recovery and a period of adaptation, animals were continuously registered for periods as long as 48 h. RESULTS: In both the light and dark phases of the cycle, significant differences in some electrographic patterns were observed between the Proechimys and Wistar animals. Although Proechimys has nocturnal activities and a pattern of polyphasic sleep similar to Wistar rats, the analysis of its sleep-wakefulness cycle indicates that the Neotropical rodent sleeps less with consequent longer periods of wakefulness when compared to Wistar rats. CONCLUSIONS: Together with previous findings of different neuroanatomical, neurophysiologic and behavioral characteristics, this study allow us to better understand adaptive differences of the Neotropical rodent Proechimys.