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1. FES Cycling and Closed-Loop Feedback Control for Rehabilitative Human–Robot Interaction

   https://doi.org/10.3390/robotics10020061  

   Cousin, Christian; Duenas, Victor; Dixon, Warren (June 2021, Robotics)

   null (Ed.)

   For individuals with movement impairments due to neurological injuries, rehabilitative therapies such as functional electrical stimulation (FES) and rehabilitation robots hold vast potential to improve their mobility and activities of daily living. Combining FES with rehabilitation robots results in intimately coordinated human–robot interaction. An example of such interaction is FES cycling, where motorized assistance can provide high-intensity and repetitive practice of coordinated limb motion, resulting in physiological and functional benefits. In this paper, the development of multiple FES cycling testbeds and safeguards is described, along with the switched nonlinear dynamics of the cycle–rider system. Closed-loop FES cycling control designs are described for cadence and torque tracking. For each tracking objective, the authors’ past work on robust and adaptive controllers used to compute muscle stimulation and motor current inputs is presented and discussed. Experimental results involving both able-bodied individuals and participants with neurological injuries are provided for each combination of controller and tracking objective. Trade-offs for the control algorithms are discussed based on the requirements for implementation, desired rehabilitation outcomes and resulting rider performance. Lastly, future works and the applicability of the developed methods to additional technologies including teleoperated robotics are outlined. 

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2. Advancing Engineered Heart Muscle Tissue Complexity with Hydrogel Composites

   https://doi.org/10.1002/adbi.202200067  

   Dickerson, Darryl_A (August 2022, Advanced Biology)

   Abstract A heart attack results in the permanent loss of heart muscle and can lead to heart disease, which kills more than 7 million people worldwide each year. To date, outside of heart transplantation, current clinical treatments cannot regenerate lost heart muscle or restore full function to the damaged heart. There is a critical need to create engineered heart tissues with structural complexity and functional capacity needed to replace damaged heart muscle. The inextricable link between structure and function suggests that hydrogel composites hold tremendous promise as a biomaterial‐guided strategy to advance heart muscle tissue engineering. Such composites provide biophysical cues and functionality as a provisional extracellular matrix that hydrogels cannot on their own. This review describes the latest advances in the characterization of these biomaterial systems and using them for heart muscle tissue engineering. The review integrates results across the field to provide new insights on critical features within hydrogel composites and perspectives on the next steps to harnessing these promising biomaterials to faithfully reproduce the complex structure and function of native heart muscle. 

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3. Analysis of Mitochondrial Function, Structure, and Intracellular Organization In Situ in Cardiomyocytes and Skeletal Muscles

   https://doi.org/10.3390/ijms23042252  

   Kuznetsov, Andrey V.; Javadov, Sabzali; Margreiter, Raimund; Hagenbuchner, Judith; Ausserlechner, Michael J. (February 2022, International Journal of Molecular Sciences)

   Analysis of the function, structure, and intracellular organization of mitochondria is important for elucidating energy metabolism and intracellular energy transfer. In addition, basic and clinically oriented studies that investigate organ/tissue/cell dysfunction in various human diseases, including myopathies, cardiac/brain ischemia-reperfusion injuries, neurodegenerative diseases, cancer, and aging, require precise estimation of mitochondrial function. It should be noted that the main metabolic and functional characteristics of mitochondria obtained in situ (in permeabilized cells and tissue samples) and in vitro (in isolated organelles) are quite different, thereby compromising interpretations of experimental and clinical data. These differences are explained by the existence of the mitochondrial network, which possesses multiple interactions between the cytoplasm and other subcellular organelles. Metabolic and functional crosstalk between mitochondria and extra-mitochondrial cellular environments plays a crucial role in the regulation of mitochondrial metabolism and physiology. Therefore, it is important to analyze mitochondria in vivo or in situ without their isolation from the natural cellular environment. This review summarizes previous studies and discusses existing approaches and methods for the analysis of mitochondrial function, structure, and intracellular organization in situ. 

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4. Pre-Clinical Cell Therapeutic Approaches for Repair of Volumetric Muscle Loss

   https://doi.org/10.3390/bioengineering7030097  

   Shayan, Mahdis; Huang, Ngan F. (September 2020, Bioengineering)

   Extensive damage to skeletal muscle tissue due to volumetric muscle loss (VML) is beyond the inherent regenerative capacity of the body, and results in permanent functional debilitation. Current clinical treatments fail to fully restore native muscle function. Recently, cell-based therapies have emerged as a promising approach to promote skeletal muscle regeneration following injury and/or disease. Stem cell populations, such as muscle stem cells, mesenchymal stem cells and induced pluripotent stem cells (iPSCs), have shown a promising capacity for muscle differentiation. Support cells, such as endothelial cells, nerve cells or immune cells, play a pivotal role in providing paracrine signaling cues for myogenesis, along with modulating the processes of inflammation, angiogenesis and innervation. The efficacy of cell therapies relies on the provision of instructive microenvironmental cues and appropriate intercellular interactions. This review describes the recent developments of cell-based therapies for the treatment of VML, with a focus on preclinical testing and future trends in the field. 

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5. Developing a Synthetic Hydrogel for Breast Tissue Engineering

   Chakraborty, A; Chukwu, C; Shama, K; Olabisi, R (October 2019, Biomedical Engineering Society)

   As part of the PI's outreach, a course-based undergraduate research experience engaged undergraduate women in research from examining the literature to identify a gap, formulating a research hypothesis, designing experiments to test the hypothesis, analyzing the data, writing and submitting an abstract and presenting the research to the scientific community. This project was as follows: Current clinical approaches to repair breast damage from cancer resection, injury, or deformity focus on synthetic implants or autologous muscle grafts. While there are drawbacks and benefits to each, neither restore the function lost should the woman desire to nurse children. Tissue engineering methods have the potential to restore breast tissue volume and function that circumvent the reconstructive limitations of contemporary surgical procedures. There is a large body of research on breast tissue engineering; however, much of the research focuses on restoring breast volume rather than breast function and seek to replace the missing tissue with fat or muscle.​ Here, we aim to develop a scaffold capable of supporting both breast adipose and glandular tissue (the main components of breast tissue) towards restoring both form and function to the breast. 

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