Thermally drawn multimodal polymer fiber

Canales, Jia and colleagues’ 2015 paper reports flexible polymer probes made by drawing a macroscopic preform into a fiber that preserves its internal arrangement. The publisher supplement identifies the MIT Department of Materials Science and Engineering, Research Laboratory of Electronics and Simons Center for the Social Brain.

Published architectures

Figure 1 shows two all-polymer cross-sections. Design I combines a central polycarbonate optical core, cyclic olefin copolymer cladding, two conductive-polyethylene electrode regions and two hollow fluidic channels. Design II places four conductive-polyethylene electrode regions around a central channel, with light guided in an outer ring. These are variants within one hardware family, not two independent cohorts.

The paper’s images give scale bars, not a universal implanted shaft diameter. No exact cross-section reconstruction is supplied here. Conductive polyethylene is a polymer composite, not the tin-wire electrode material of the separate multielectrode fiber.

Functions and backend

• Light delivery, electrical recording and fluid injection are integrated within the same fiber.
• Supplementary Figure 1 reports optical losses of 2.7 dB/cm for design I and 1.6 dB/cm for design II. These are reported measurements for these designs, not a general value for every drawn fiber.
• Supplementary Figure 2 demonstrates injections at 1, 10, 20, 50, 80 and 100 nl/s, including 90-degree bending at a 4 mm curvature radius, with n = 3.
• Supplementary Figure 16 shows electrodes exposed through cladding removal, copper-wire connections made with silver paint, a PCB, fluidic tubing and an optical ferrule. The assembly is externally connected, not a wireless implant.

Demonstrated use and limits

The linked mouse study reports recording, optogenetic stimulation and drug delivery. Published Figure 2 shows design I optoelectrophysiology through two months after implantation; it does not establish indefinite stability, human use or a clinical decoder.

The 2021 hydrogel-hybrid probe combines separate functional fibers in a hydrogel matrix. That later assembly is distinct from this 2015 drawn polymer cross-section. Neither the 2021 collective connectorization limit nor its six-month result is transferred to this hardware.

Primary sources

• 2015 paper and abstract.
• Figure 1: both cross-sections and characterization.
• Figure 2: two-month optoelectrophysiology and drug perturbation.
• Publisher supplement: affiliations, fluidics and backend.

The full main article is subscription-restricted in the inspected publisher page. This entry uses the accessible abstract, figure captions and complete supplement; no missing methods or dimensions are filled from an unofficial mirror.