One drawn polymer fiber records and doses at several depths of a mouse brain

Each of the eight channels can be a drug line or a sleeve for a recording wire, and the release describes both uses for the same openings ^[6]. Fluid ports and electrodes therefore come out of one pool: at most eight between them ^[16]. The release does not say how the team divided the eight in the mouse experiments, or how long the fiber stayed in place ^[18].

The argument for the design is partly about what the surgery itself does. Kunyang Sui, the postdoc who developed the concept with Associate Professor Christos Markos, said: "Most current brain implants are based on hard materials such as silicon, which can irritate the brain and trigger inflammatory reactions in the tissue. The new implant differs in that it is made of soft, plastic-like optical fibers and has a specially angled tip that makes it smaller and reduces the damage caused when it is placed in the brain" ^[10][12].

Those are two separable claims. An angled tip is about insertion; softness is about residence, since the fiber bends with tissue instead of pressing rigidly through it, and stiffer implants can provoke inflammation while they sit there ^[8][17]. The mouse tests reported here speak to whether the fiber functions ^[4]. What a month in place does to the surrounding tissue is a separate measurement.

For now the group presents the mAxialtrode as a research tool, pointed at how signals travel between brain layers during epilepsy, memory and decision-making ^[13]. Further out, they describe delivering a drug at one location while stimulating selected areas electrically or with light ^[14]. Sui cautions that routine clinical use would require extensive testing, further development and regulatory approvals ^[11].

For a lab that currently implants a probe, a cannula and a light fiber separately, adoption turns on two numbers rather than the count of functions: how well a thin metal wire threaded down a microfluidic channel records, and whether a channel that has held a wire still passes fluid. The work is published in Advanced Science, with DTU, the University of Copenhagen and University College London among the institutions involved ^[3][2].