# Robust minimally-invasive microfabricated stainless steel neural interfaces for high resolution recording

## TL;DR

Researchers developed durable stainless steel neural probes for high-resolution brain recordings in large animals, which could help advance human neurotherapeutics.

## Contribution

The paper introduces 'steeltrodes', a novel microfabricated stainless steel neural probe for long, high-density recordings in primates.

## Key findings

- Steeltrodes enabled 8 cm long, 300 µm wide probes with high-resolution laminar recordings in macaque auditory cortex.
- The probes were safely implanted in rats with minimal cortical damage and provided high-fidelity neural recordings.
- The design supports both flexible and rigid components, making it suitable for deep brain structures in primates.

## Abstract

Understanding brain function and developing effective neurotherapeutics require high-resolution electrophysiologyical recording across large primate brains. To achieve this goal, minimally invasive, compact, long, and high-density implantable neural probes are needed. Conventional silicon-based probes, designed for rodents, cannot be directly scaled to larger brains because silicon’s brittleness restricts long, high–aspect-ratio designs. Stainless steel is a biocompatible, resilient, and less brittle alternative for making neural probes, though its microfabrication is less explored. Here, we introduce “steeltrodes”, customizable microfabricated stainless steel neural probes enabling high-density multi-layer electrode integration. We demonstrate 8 cm long, ~300 µm wide probes, featuring rigid shanks with optional flexible cables for in vivo high-resolution laminar recording from macaque auditory cortex. In rats, these probes can be safely implanted through intact dura with minimal cortical damage. High-fidelity recordings of single units and local field potentials in macaques highlight the potential of steeltrodes for translation to human applications, enabling both inter- and intraoperative neural recordings.

Understanding brain functions in large animals requires long, robust neural probes. Here, the authors present a microfabricated stainless steel probe that enables high-density recordings in deep brain structures in primates