Metal-Organic Frameworks Modified Organic Bulk Heterojunction Interfaces for Effective Nongenetic Neuromodulation

Area of Science:

• Materials Science
• Neuroscience
• Biotechnology

Background:

• Photoactive organic semiconductors, like bulk heterojunctions (BHJs), offer potential for flexible optical neuromodulation devices.
• Current BHJ devices face limitations due to poor interfaces with biological tissues, hindering signal transduction and biocompatibility.

Purpose of the Study:

• To enhance the interface between BHJs and biological tissues for improved neuromodulation.
• To explore the use of conductive and porous metal-organic frameworks (MOFs) as an interfacial layer.

Main Methods:

• Fabrication of flexible devices using BHJs modified with a metal-organic framework (MOF) interfacial layer.
• Characterization of the MOF-BHJ interface for charge injection capacity and biocompatibility.
• Testing of device performance for nongenetic neuromodulation of cultured neurons and *in vivo* nerve stimulation.

Main Results:

• The MOF layer boosted charge injection capacity at the BHJ-biological interface by over 400 times.
• MOF-modified BHJ devices demonstrated efficient electrical-to-ionic signal transduction for neural modulation under visible and near-infrared light.
• *In vivo* stimulation of rat sciatic nerves achieved a 700-fold reduction in required light intensity compared to unmodified devices.

Conclusions:

• Interfacial engineering with porous MOFs significantly improves BHJ-based photocapacitors for neuromodulation.
• This approach enhances biocompatibility and signal transduction, enabling precise, low-light optical control of neural activity.
• MOF-modified BHJs offer a promising platform for advanced prosthetic biointerfaces and neuromodulation technologies.