A versatile system for neuromuscular stimulation and recording in the mouse model using a lightweight magnetically coupled headmount.

Neural stimulation and recording in rodents are common methods to better understand the nervous system and improve the quality of life of individuals who are suffering from neurological disorders (e.g., epilepsy), as well as for permanent reduction of chronic pain in patients with neuropathic pain and spinal-cord injury. This method requires a neural interface (e.g., a headmount) to couple the implanted neural device with instrumentation system. The size and the total weight of such headmounts should be designed in a way to minimize its effect on the movement of the animal. This is a crucial factor in gait, kinematic, and behavioral neuroscience studies of freely moving mice. Here we introduce a lightweight 'snap-in' electro-magnetic headmount that is extremely small, and uses strong neodymium magnetics to enable a reliable connection without sacrificing the lightweight of the device. Additionally, the headmount requires minimal surgical intervention during the implantation, resulting in minimal tissue damage. The device has demonstrated itself to be robust, and successfully provided direct electrical stimulation of nerve and electrical muscle stimulation and recording, as well as powering implanted LEDs for optogenetic use scenarios.

Gradient porous fibrous scaffolds: a novel approach to improving cell penetration in electrospun scaffolds.

Electrospinning is an increasingly popular technique to generate 3D fibrous tissue scaffolds that mimic the submicron sized fibers of extracellular matrices. A major drawback of electrospun scaffolds is the small interfibrillar pore size, which normally prevents cellular penetration in between fibers. In this study, we introduced a novel process, based on electrospinning, to manufacture a unique gradient porous fibrous (GPF) scaffold from soy protein isolate (SPI). The pore sizes in the GPF scaffolds gradually increase from one side of the scaffold to the other, ranging from 7.8 ± 2.5 µm in the small pore side, 21.4 ± 10.3 µm in the mid layer to 58.0 ± 23.6 µm in the large pore side. The smallest pores of the GPF scaffolds appeared to be somewhat larger than those in conventionally electrospun SPI scaffolds (4.2 ± 1.3 µm). Hydrated GPF scaffolds exhibited J-shaped stress-strain curves, reminiscent of those for soft biological scaffolds. Attachment, spreading, and proliferation of human dermal fibroblasts (HDFB) were supported on both the small and the large pore sides of the GPF scaffolds. Cultured HDFB and murine RAW 264.7 macrophages penetrated significantly deeper (98.7 ± 24.2 µm and 53.3 ± 9.6 µm, respectively) into the larger pores than when seeded onto the small pore side of GPF scaffolds (22.8 ± 6.2 µm and 25.7 ± 7.3 µm) and control SPI scaffolds. (11.3 ± 3.8 µm and 15.3 ± 3.1 µm). This study introduces a novel fabrication technique, which, by convergence of several biofabrication technologies, produces scaffolds with enhanced cellular penetration.