A superoxide scavenging coating for improving tissue response to neural implants.

Area of Science:

• Biomaterials Science
• Neuroscience
• Chemical Engineering

Background:

• Implantable neural electrodes are crucial for brain-computer interfaces and deep brain stimulation.
• Chronic inflammation and neuronal loss near electrodes, mediated by reactive oxygen and nitrogen species (RONS), impair device performance.
• Developing strategies to mitigate RONS-induced damage is essential for long-term neural implant efficacy.

Purpose of the Study:

• To synthesize and evaluate a superoxide dismutase mimic compound (iSODm) for covalent attachment to neural probe surfaces.
• To assess the efficacy of iSODm coatings in reducing RONS and subsequent neuronal damage in vitro and in vivo.
• To improve the biocompatibility and chronic performance of neural electrodes.

Main Methods:

• Synthesis of manganese(III) meso-tetrakis-(N-(2-aminoethyl)pyridinium-2-yl) porphyrin (iSODm) with superoxide scavenging activity.
• Covalent immobilization of iSODm onto neural probe surfaces.
• In vitro testing using microglia cell cultures to assess RONS production and inflammatory marker expression.
• In vivo implantation of coated electrodes in rodents to evaluate oxidative stress markers and neuronal apoptosis after one week.

Main Results:

• The synthesized iSODm compound demonstrated high catalytic superoxide scavenging activity.
• iSODm coatings significantly reduced superoxide production and modulated inflammatory gene expression in microglia cell cultures.
• Implantation of iSODm-coated electrodes resulted in significantly lower oxidative stress markers and reduced neuronal apoptosis adjacent to the electrode surface after one week.

Conclusions:

• Covalently immobilizing iSODm on neural electrodes effectively mitigates RONS-induced inflammation and neuronal degeneration.
• This biomimetic approach offers a promising strategy to enhance the long-term performance and biocompatibility of neural implants.
• Reducing oxidative stress at the neural-implant interface is critical for advancing neural prostheses for clinical applications.