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1. Injectable non-leaching tissue-mimetic bottlebrush elastomers as an advanced platform for reconstructive surgery

   https://doi.org/10.1038/s41467-021-23962-8  

   Dashtimoghadam, Erfan; Fahimipour, Farahnaz; Keith, Andrew N.; Vashahi, Foad; Popryadukhin, Pavel; Vatankhah-Varnosfaderani, Mohammad; Sheiko, Sergei S. (December 2021, Nature Communications)

   null (Ed.)

   Abstract Current materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation. 

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2. Fouling-resistant zwitterionic polymers for complete prevention of postoperative adhesion

   https://doi.org/10.1073/pnas.2012491117  

   Zhang, Ershuai; Song, Boyi; Shi, Yuanjie; Zhu, Hui; Han, Xiangfei; Du, Hong; Yang, Chengbiao; Cao, Zhiqiang (November 2020, Proceedings of the National Academy of Sciences)

   Postoperative adhesions are most common issues for almost any types of abdominal and pelvic surgery, leading to adverse consequences. Pharmacological treatments and physical barrier devices are two main approaches to address postoperative adhesions but can only alleviate or reduce adhesions to some extent. There is an urgent need for a reliable approach to completely prevent postoperative adhesions and to significantly improve the clinical outcomes, which, however, is unmet with current technologies. Here we report that by applying a viscous, cream-like yet injectable zwitterionic polymer solution to the traumatized surface, postoperative adhesion was completely and reliably prevented in three clinically relevant but increasingly challenging models in rats. The success rate of full prevention is over 93% among 42 animals tested, which is a major leap in antiadhesion performance. Clinically used Interceed film can hardly prevent the adhesion in any of these models. Unlike current antiadhesion materials serving solely as physical barriers, the “nonfouling” zwitterionic polymer functioned as a protective layer for antiadhesion applications with the inherent benefit of resisting protein/cell adhesions. The nonfouling nature of the polymer prevented the absorption of fibronectins and fibroblasts, which contribute to the initial and late-stage development of the adhesion, respectively. This is the key working mechanism that differentiated our “complete prevention” approach from current underperforming antiadhesion materials. This work implies a safe, effective, and convenient way to fully prevent postoperative adhesions suffered by current surgical patients. 

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3. 3D printed conformal microfluidics for isolation and profiling of biomarkers from whole organs

   https://doi.org/10.1039/C7LC00468K  

   Singh, Manjot; Tong, Yuxin; Webster, Kelly; Cesewski, Ellen; Haring, Alexander P.; Laheri, Sahil; Carswell, Bill; O'Brien, Timothy J.; Aardema, Charles H.; Senger, Ryan S.; et al (January 2017, Lab on a Chip)

   The ability to interface microfluidic devices with native complex biological architectures, such as whole organs, has the potential to shift the paradigm for the study and analysis of biological tissue. Here, we show 3D printing can be used to fabricate bio-inspired conformal microfluidic devices that directly interface with the surface of whole organs. Structured-light scanning techniques enabled the 3D topographical matching of microfluidic device geometry to porcine kidney anatomy. Our studies show molecular species are spontaneously transferred from the organ cortex to the conformal microfluidic device in the presence of fluid flow through the organ-conforming microchannel. Large animal studies using porcine kidneys ( n = 32 organs) revealed the profile of molecular species in the organ-conforming microfluidic stream was dependent on the organ preservation conditions. Enzyme-linked immunosorbent assay (ELISA) studies revealed conformal microfluidic devices isolate clinically relevant metabolic and pathophysiological biomarkers from whole organs, including heat shock protein 70 (HSP-70) and kidney injury molecule-1 (KIM-1), which were detected in the microfluidic device as high as 409 and 12 pg mL −1 , respectively. Overall, these results show conformal microfluidic devices enable a novel minimally invasive ‘microfluidic biopsy’ technique for isolation and profiling of biomarkers from whole organs within a clinically relevant interval. This achievement could shift the paradigm for whole organ preservation and assessment, thereby helping to relieve the organ shortage crisis through increased availability and quality of donor organs. Ultimately, this work provides a major advance in microfluidics through the design and manufacturing of organ-conforming microfluidic devices and a novel technique for microfluidic-based analysis of whole organs. 

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4. High‐Density, Conformable Conducting Polymer‐Based Implantable Neural Probes for the Developing Brain

   https://doi.org/10.1002/adhm.202304164  

   Ma, Liang; Wisniewski, Duncan_J; Cea, Claudia; Khodagholy, Dion; Gelinas, Jennifer_N (April 2024, Advanced Healthcare Materials)

   Abstract Neurologic and neuropsychiatric disorders substantially impact the pediatric population, but there is a lack of dedicated devices for monitoring the developing brain in animal models, leading to gaps in mechanistic understanding of how brain functions emerge and their disruption in disease states. Due to the small size, fragility, and high water content of immature neural tissue, as well as the absence of a hardened skull to mechanically support rigid devices, conventional neural interface devices are poorly suited to acquire brain signals without inducing damage. Here, the authors design conformable, implantable, conducting polymer‐based probes (NeuroShanks) for precise targeting in the developing mouse brain without the need for skull‐attached, rigid mechanical support structures. These probes enable the acquisition of high spatiotemporal resolution neurophysiologic activity from superficial and deep brain regions across unanesthetized behavioral states without causing tissue disruption or device failure. Once implanted, probes are mechanically stable and permit precise, stable signal monitoring at the level of the local field potential and individual action potentials. These results support the translational potential of such devices for clinically indicated neurophysiologic recording in pediatric patients. Additionally, the role of organic bioelectronics as an enabling technology to address questions in developmental neuroscience is revealed. 

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5. In vitro models of soft tissue damage by implant-associated frictional shear stresses

   https://doi.org/10.1177/13506501221132897  

   Rosas, Jonah M.; Atkins, Dixon J.; Chau, Allison L.; Chen, Yen-Tsung; Bae, Rachel; Cavanaugh, Megan K.; Espinosa Lima, Ricardo I.; Bordeos, Andrew; Bryant, Michael G.; Pitenis, Angela A. (May 2023, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology)

   Silicone elastomer medical implants are ubiquitous in medicine, particularly for breast augmentation. However, when these devices are placed within the body, disruption of the natural biological interfaces occurs, which significantly changes the native energy-dissipation mechanisms of living systems. These new interfaces can introduce non-physiological contact pressures and tribological conditions that provoke inflammation and soft tissue damage. Despite their significance, the biotribological properties of implant-tissue and implant-extracellular matrix (ECM) interfaces remain poorly understood. Here, we developed an in vitro model of soft tissue damage using a custom-built in situ biotribometer mounted onto a confocal microscope. Sections of commercially-available silicone breast implants with distinct and clinically relevant surface roughness ([Formula: see text]m, [Formula: see text]m, and [Formula: see text]m) were mounted to spherically-capped hydrogel probes and slid against collagen-coated hydrogel surfaces as well as healthy breast epithelial (MCF10A) cell monolayers to model implant-ECM and implant-tissue interfaces. In contrast to the “smooth” silicone implants ([Formula: see text]m), we demonstrate that the “microtextured” silicone implant ([Formula: see text]m) induced higher frictional shear stress ([Formula: see text]  Pa), which led to greater collagen removal and cell rupture/delamination. Our studies may provide insights into post-implantation tribological interactions between silicone breast implants and soft tissues. 

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