Repair severed nerve connections through a multi-branch microchannel scaffold to control the direction of the regenerated nerve

Damage to the peripheral nervous system may result in functional abnormalities due to disrupted nerve connections. Existing methods of repairing severed nerve connections in the peripheral nervous system have limitations and disadvantages such as a limited availability of donor nerves and a lack of control of the direction of nerve regeneration within nerve conduits. A handcrafted multi-branch microchannel scaffold improves upon the current methods of nerve repair by incorporating microchannels, which guide and accommodate the nerve regeneration to distal ends, allowing for the treatment of nerve injuries involving multiple branches with fewer surgeries. This scaffold is also made more accessible by being fabricated with commercially available materials, microwires, silastic tubes and PDMS. Moreover, the designs of the multi-branch scaffold can be modified for any branching nerve using the procedure. The scaffold used in the study was designed specifically for the sciatic nerve, which branches out to the tibial, sural, and common peroneal serves, and was implanted in the Lewis rats with a severed sciatic nerve and three distal nerve branches to demonstrate the effectiveness of the nerve scaffold

Biocompatible microchannel scaffold with microwires for recording regenerative peripheral nerve neural spikes

A new process for the fabrication of a microchannel scaffold with microwires for peripheral nerve applications is presented. This microchannel scaffold implemented between the ends of nerves, the axons of which regenerate through microchannel in scaffold and fixed microelectrodes. This device is entirely handcrafted using commercially available materials such as microwires, PDMS film, liquid PDMS, dental cement, and epoxy glue. This device was implemented in the a Lewis rat sciatic nerve to better analyze the electrical signals of regenerated axons. 64-electrode microchannel scaffolds were developed for both peripheral nerve interfacing and peripheral nerve regeneration. The microwires were used for recording electrode to capture neural signal from the regenerated peripheral nerves. To further differentiate the methodology, the new addition of a ribbon cable will facilitate the transmission of the electrical signals. A total of eight devices have been developed, the nerve regeneration were examined four weeks after device implantation

PDMS microchannel scaffolds for the isolation of individual axon regeneration

Injuries to the peripheral nervous system often result in the loss of sensory or motor function within the effected nerve. Nerve scaffolds provide the mechanical support and topographical cues to axon regeneration such that the gap within the injured nerve is bridged and functional recovery is restored. The Microchannel Peripheral Nerve Scaffold, µPNS, was fabricated from PDMS using micromachining techniques that allow for the unprecedented control of microchannel dimensions and paths and therefore, the production of highly customizable Nerve scaffolds for peripheral nerve regeneration applications. The device was then implanted within the sciatic nerves of a series of Lewis rats, and was removed after 4 weeks. Each device was then disassembled layer by layer so that every microchannel could be individually inspected. Longitudinal views of axon morphology throughout the length of the scaffolds were collected using three dimensional confocal imaging of the small axon population sample sets, including branching behaviors

Peripheral nerve growth within a hydrogel microchannel scaffold supported by a kink‐resistant conduit

Nerve repair in several mm‐long nerve gaps often requires an interventional technology. Microchannel scaffolds have proven effective for bridging nerve gaps and guiding axons in the peripheral nervous system (PNS). Nonetheless, fabricating microchannel scaffolds at this length scale remains a challenge and/or is time consuming and cumbersome. In this work, a simple computer‐aided microdrilling technique was used to fabricate 10 mm‐long agarose scaffolds consisting of 300 µm‐microchannels and 85 µm‐thick walls in less than an hour. The agarose scaffolds alone, however, did not exhibit adequate stiffness and integrity to withstand the mechanical stresses during implantation and suturing. To provide mechanical support and enable suturing, poly caprolactone (PCL) conduits were fabricated and agarose scaffolds were placed inside. A modified salt‐leaching technique was developed to introduce interconnected porosity in PCL conduits to allow for tuning of the mechanical properties such as elastic modulus and strain to failure. It was shown that the PCL conduits were effective in stabilizing the agarose scaffolds in 10 mm‐long sciatic nerve gaps of rats for at least 8 weeks. Robust axon ingress and Schwann cell penetration were observed within the microchannel scaffolds without using growth factors. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3392–3399, 2017.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139110/1/jbma36186_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139110/2/jbma36186.pd

A handcrafted multi-branch nerve scaffold for in vivo peripheral nerve regeneration

Arm and leg peripheral nerve injuries contribute largely to functional disability. These injuries seldom affect a single-line nerve; rather the injury goes beyond and disrupts the nerve tissue across multiple nerve paths. Here we investigate handcrafted PDMS based multi-branch nerve guidance conduit, which addresses this crucial branching from the sciatic nerve to aid with the regeneration to their appropriate distal targets. The design concept of the developed multiple branch nerve scaffolds is not specific for the sciatic nerve but can be modified for general use of all peripheral nerves and additional applications. Microchannels are also fabricated into a device in order to guide axons to reach the distal ends, which in turn allow regenerating nerves to reach the target muscles. Experiments are performed on Lewis rats to demonstrate the effectiveness of this nerve conduit. Successful nerve regeneration was confirmed from histological analysis of the harvested nerves from all four branches

Handcrafted Microwire Regenerative Peripheral Nerve Interfaces with Wireless Neural Recording and Stimulation Capabilities

A scalable microwire peripheral nerve interface was developed, which interacted with regenerated peripheral nerves in microchannel scaffolds. Neural interface technologies are envisioned to facilitate direct connections between the nervous system and external technologies such as limb prosthetics or data acquisition systems for further processing. Presented here is an animal study using a handcrafted microwire regenerative peripheral nerve interface, a novel neural interface device for communicating with peripheral nerves. The neural interface studies using animal models are crucial in the evaluation of efficacy and safety of implantable medical devices before their use in clinical studies. 16- electrode microwire microchannel scaffolds were developed for both peripheral nerve regeneration and peripheral nerve interfacing. The microchannels were used for nerve regeneration pathways as a scaffolding material and the embedded microwires were used as a recording electrode to capture neural signals from the regenerated peripheral nerves. Wireless stimulation and recording capabilities were also incorporated to the developed peripheral nerve interface which gave the freedom of the complex experimental setting of wired data acquisition systems and minimized the potential infection of the animals from the wire connections. A commercially available wireless recording system was efficiently adopted to the peripheral nerve interface. The 32-channel wireless recording system covered 16-electrode microwires in the peripheral nerve interface, two cuff electrodes, and two electromyography electrodes. The 2-channel wireless stimulation system was connected to a cuff electrode on the sciatic nerve branch and was used to make evoked signals which went through the regenerated peripheral nerves and were captured by the wireless recording system at a different location. The successful wireless communication was demonstrated in the result section and the future goals of a wireless neural interface for chronic implants and clinical trials were discussed together

Microwire regenerative peripheral nerve interfaces with wireless recording and stimulation capabilities

A scalable microwire peripheral nerve interface was developed, which interacted with regenerated peripheral nerves in microchannel scaffolds. Neural interface technologies are envisioned to facilitate direct connections between the nervous system and external technologies such as limb prosthetics or data acquisition systems for further processing. Presented here is an animal study using a handcrafted microwire regenerative peripheral nerve interface, a novel neural interface device for communicating with peripheral nerves. The neural interface studies using animal models are crucial in the evaluation of efficacy and safety of implantable medical devices before their use in clinical studies.16-electrode microwire microchannel scaffolds were developed for both peripheral nerve regeneration and peripheral nerve interfacing. The microchannels were used for nerve regeneration pathways as a scaffolding material and the embedded microwires were used as a recording electrode to capture neural signals from the regenerated peripheral nerves. Wireless stimulation and recording capabilities were also incorporated to the developed peripheral nerve interface which gave the freedom of the complex experimental setting of wired data acquisition systems and minimized the potential infection of the animals from the wire connections

Investigating the Effects of Shear Stress on the Protein Expression of Lymphatic Endothelial Cells (LECs)

The lymphatic system plays three main important roles: Its cells are primarily responsible for the immune response of the human body, it represents a separate circulatory system, and it is involved in the transport of select nutrients from the digestive system to the circulatory system. All of these functions rely on the generation and regulation of the lymph flow along the lymphatic network. Any malfunction in the flow within the lymphatic network could potentially lead to an anomaly in the body as whole. Moreover, any imbalance within the fluid reabsorption of the interstitial fluid could lead to edema, which is a common problem worldwide. The lymphatic vasculature acts also as a conduit for cancer metastasis. My research will investigate the effects of shear forces on gene expression within lymphatic endothelial cells. Identification of factors that trigger gene expression in LECs also has implications for cancer metastasis as well as the pathophysiology of lymphatic edema. The expected outcomes for this research project is that it may identify changes in shear forces that may result in altered gene expression in lymphatic endothelial cells that may have a role in lymphatic edema

UTRGV Commencement – Fall 2016

https://scholarworks.utrgv.edu/utrgvcommencement/1008/thumbnail.jp