Hexbyte Glen Cove Bioengineered hybrid muscle fiber for regenerative medicine thumbnail

Hexbyte Glen Cove Bioengineered hybrid muscle fiber for regenerative medicine

Hexbyte Glen Cove

Schematic illustration of the 3D skeletal muscle-like bioengineered constructs Credit: Institute for Basic Science

Muscle constitutes the largest organ in humans, accounting for 40% of body mass, and it plays an essential role in maintaining life. Muscle tissue is notable for its unique ability for spontaneous regeneration. However, in serious injuries such as those sustained in car accidents or tumor resection which results in a volumetric muscle loss (VML), the muscle’s ability to recover is greatly diminished. Currently, VML treatments comprise surgical interventions with autologous muscle flaps or grafts accompanied by physical therapy. However, surgical procedures often lead to reduced muscular function, and in some cases result in a complete graft failure. Thus, there is a demand for additional therapeutic options to improve muscle loss recovery.

A promising strategy to improve the functional capacity of the damaged muscle is to induce de novo regeneration of skeletal muscle via the integration of transplanted cells. Diverse types of cells, including (), myoblasts, and , have been used to treat muscle loss. However, invasive muscle biopsies, poor cell availability, and limited long-term maintenance impede clinical translation, where millions to billions of mature cells may be needed to provide therapeutic benefits.

Another important issue is controlling the three-dimensional microenvironment at the injury site to ensure that the transplanted cells properly differentiate into muscle tissues with desirable structures. A variety of natural and synthetic biomaterials have been used to enhance the survival and maturation of transplanted cells while recruiting host cells for muscle regeneration. However, there are unsolved, long-lasting dilemmas in tissue development. Natural scaffolds exhibit high cell recognition and cell binding affinity, but often fail to provide mechanical robustness in large lesions or load-bearing tissues that require long-term mechanical support. In contrast, synthetic scaffolds provide a precisely engineered alternative with tunable mechanical and physical properties, as well as tailored structures and biochemical compositions, but are often hampered by lack of cell recruitment and poor integration with host tissue.

SEM image of the porous PCL scaffold with MEM Credit: Institute for Basic Science

To overcome these challenges, a research team at the Center for Nanomedicine within the Institute for Basic Science (IBS) in Seoul, South Korea, Yonsei University, and the Massachusetts Institute of Technology (MIT) devised a novel protocol for artificial muscle regeneration. The team achieved effective treatment of VML in a mouse model by employing direct cell reprogramming technology in combination with a natural-synthetic hybrid scaffold.

Direct cell reprogramming, also called direct conversion, is an efficient strategy that provides effective cell therapy because it allows the rapid generation of patient-specific target cells using autologous cells from the tissue biopsy. Fibroblasts are the cells that are commonly found within the connective tissues, and they are extensively involved in wound healing. As the fibroblasts are not terminally differentiated cells, it is possible to turn them into induced myogenic progenitor cells (iMPCs) using several different transcription factors. Herein, this strategy was applied to provide iMPC for engineering.

In order to provide structural support for the proliferating muscle cells, polycaprolactone (PCL), was chosen as a material for the fabrication of a porous scaffold due to its high biocompatibility. While salt-leaching is a widely used method to create porous materials, it is mostly limited to producing closed porous structures. To overcome this limitation, the researchers augmented the conventional salt leaching method with thermal drawing to produce customized PCL fiber scaffolds. This technique facilitated high-throughput fabrication of porous fibers with controlled stiffness, porosity, and dimensions that enable precise tailoring of the scaffolds to the injury sites.

Recovery of the ablated muscle tissue a) 1 week and b-c) 4 weeks after transplantation Credit: Institute for Basic Science

However, the synthetic PCL fiber scaffolds alone do not provide optimal biochemical and local mechanical cues that mimic muscle-specific microenvironment. Hence the construction of a hybrid scaffold was completed through the incorporation of decellularized muscle extracellular matrix (MEM) hydrogel into the PCL structure. Currently, MEM is one of the most widely used natural biomaterials for the treatment of VML in clinical practice. Thus, the researchers believe that hybrid scaffolds engineered with MEM have a huge potential in clinical applications.

The resultant bioengineered muscle fiber constructs showed mechanical stiffness similar to that of muscle tissues and exhibited enhanced muscle differentiation and elongated muscle alignment in vitro. Furthermore, implantation of bioengineered muscle constructs in the VML not only promoted muscle regeneration with increased innervation and angiogenesis but also facilitated the functional recovery of damaged muscles. The research team notes: “The hybrid muscle construct might have guided the responses of exogenously added reprogrammed muscle and infiltrating host cell populations to enhance functional muscle regeneration by orchestrating differentiation, paracrine effect, and constructive remodeling.”

Prof. Cho Seung-Woo from the IBS Center for Nanomedicine and Yonsei University College of Life Science and Biotechnology who led this study notes, “Further studies are required to elucidate the mechanisms of regeneration by our hybrid constructs and to empower the clinical translation of cell-instructive delivery platforms.”



More information:
Yoonhee Jin, Dena Shahriari, Eun Je Jeon, Seongjun Park, Yi Sun Choi, Jonghyeok Back, Hyungsuk Lee, Polina Anikeeva and Seung-Woo Cho. Functional Skeletal Muscle Regeneration with Thermally Drawn Porous Fibers and Reprogrammed Muscle Progenitors for Volumetric Muscle Injury. Advanced Materials, 2021.

Citation:
Bioengineered hybrid muscle fiber for regenerative medicine (2021, February 21)
retrieved 22 February 2021
from https://phys.org/news/2021-02-bioengineered-hybrid-muscle-fiber-regenerative.html

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Hexbyte Glen Cove Zinc-ion hybrid capacitors with ideal anions in the electrolyte show extra-long performance thumbnail

Hexbyte Glen Cove Zinc-ion hybrid capacitors with ideal anions in the electrolyte show extra-long performance

Hexbyte Glen Cove

Credit: Wiley

Metal-ion hybrid capacitors combine the properties of capacitors and batteries. One electrode uses the capacitive mechanism, the other the battery-type redox processes. Scientists have now scrutinized the role of anions in the electrolyte. The results, which have been published in the journal Angewandte Chemie, reveal the importance of sulfate anions. Sulfate-based electrolytes gave zinc-ion hybrid capacitors outstanding performance and extra-long operability.

Capacitors can uptake and release an enormous amount of charge in a short time, whereas batteries can store a lot of energy in a small volume. To combine both properties, scientists are investigating hybrid electrochemical cells, which contain both capacitor- and battery-type electrodes. Among these cells, researchers have identified metal-ion hybrid capacitors as especially promising devices. Here, the positive electrode includes pseudocapacitive properties, which means it can also store energy in the manner of a battery, by intercalation of the metal ions, while the negative electrode is made of a redox-active metal.

However, their has long been neglected, says Chunyi Zhi who is investigating battery materials together with his team at the City University of Hong Kong. The researchers believe the type of electrolyte affects the performance of the device. “Paying more attention to the introduction of appropriate anions can effectively improve the power and energy density of a capacitor,” they say.

The researchers focused their attention on zinc-ion capacitors. This cell type consists of a zinc metal anode and a cathode made of titanium nitride nanofibers. The nanofibers are robust, and their allows the electrolyte to infiltrate. The scientists argue that the electrolyte anions, when attached to the titanium nitride surface, make the material more conductive. Moreover, the adsorbed anions may directly contribute to the charging process. The charging of the hybrid capacitor involves the extraction of the intercalated zinc ions.

Zhi and his colleagues compared the effects of three electrolyte anions: , acetate, and chloride. They looked at both their binding to the electrode surface and the performances of the electrochemical cells. It was a clear result.

The scientists reported that the sulfate anions stood out among the three anions. They observed that cells based on a zinc sulfate electrolyte performed best, and the sulfates bound stronger to the titanium nitride surface than the other anions. Moreover, sulfate-treated electrodes showed the lowest self-discharging. The authors attributed the findings to the electronic effects of sulfate. Its electron-pulling nature provides tight binding to the surface atoms and prevents the from self-discharging, the authors concluded.

For a zinc-sulfate-based zinc-ion hybrid , the scientists reported high-performance operation for more than nine months. Moreover, these devices are flexible, which is especially useful for portable electronics. The scientists tested the device in an electronic watch and found excellent performance.



More information:
Zhaodong Huang et al. Effects of Anion Carriers on Capacitance and Self‚ÄźDischarge Behaviors of Zinc Ion Capacitors, Angewandte Chemie International Edition (2020). DOI: 10.1002/anie.202012202

Citation:
Zinc-ion hybrid capacitors with ideal anions in the electrolyte show extra-long performance (2020, November 13)
retrieved 14 November 2020
from https://phys.org/news/2020-11-zinc-ion-hybrid-capacitors-ideal-anions.html

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