Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

The cell microenvironment has emerged as a key determinant of cell behavior and function in development, physiology, and pathophysiology. The extracellular matrix (ECM) within the cell microenvironment serves not only as a structural foundation for cells but also as a source of three-dimensional (3D) biochemical and biophysical cues that trigger and regulate cell behaviors. Increasing evidence suggests that the 3D character of the microenvironment is required for development of many critical cell responses observed in vivo, fueling a surge in the development of functional and biomimetic materials for engineering the 3D cell microenvironment. Progress in the design of such materials has improved control of cell behaviors in 3D and advanced the fields of tissue regeneration, in vitro tissue models, large-scale cell differentiation, immunotherapy, and gene therapy. However, the field is still in its infancy, and discoveries about the nature of cell–microenvironment interactions continue to overturn much earl...

Functional and Biomimetic Materials for Engineering of the Three-Dimensional Cell Microenvironment

One of the most intriguing protein materials found in nature is bone, a material composed of assemblies of tropocollagen molecules and tiny hydroxyapatite mineral crystals that form an extremely tough, yet lightweight, adaptive and multifunctional material. Bone has evolved to provide structural support to organisms, and therefore its mechanical properties are of great physiological relevance. In this article, we review the structure and properties of bone, focusing on mechanical deformation and fracture behavior from the perspective of the multidimensional hierarchical nature of its structure. In fact, bone derives its resistance to fracture with a multitude of deformation and toughening mechanisms at many size scales ranging from the nanoscale structure of its protein molecules to the macroscopic physiological scale.

On the Mechanistic Origins of Toughness in Bone

Incorporating gold nanowires into scaffolds used to create heart patches can improve electrical communication between cells and enhance the growth of tissues.

Nanowired three-dimensional cardiac patches

Hydrogels as intelligent materials: A brief review of synthesis, properties and applications

Electroconductive natural polymer-based hydrogels.

Flexible strain sensors have been widely used in wearable electronic devices for body physical parameter capturing. However, regardless of the stretchability of the sensing material, the resolution of small strain changes or the hysteresis between loading/unloading states has always limited the various applications of these sensors. In this paper, a microfluidic flexible strain sensor was achieved by introducing liquid metal eutectic gallium indium (EGaIn) embedded into a wave-shaped microchannel elastomeric matrix (300 μm width × 70 μm height). The microfluidic sensor can withstand a strain of up to 320%, and the hysteresis performance was also improved from 6.79 to 1.02% by the wave-patterned structure which can restrain the viscoelasticity of the elastomer effectively. Moreover, an enhanced wave-shaped strain sensor was fabricated by increasing the length of the microfluidic channel; it has high sensitivity (GF = 4.91) and resolution, and even as low as 0.09% strain change could be detected, which is capable of resolving microdeformation; besides, the enhanced wave-shaped strain sensor exhibits quick response time (t = 116 ms), long-term stability, and durability under periodic dynamic load. As an example of potential applications, the enhanced flexible sensor showed excellent mechanical compliance and was successfully applied as a conceptual wearable device for distinctively monitoring various kinds of human body and robot activities, such as the different states of the finger, neck, breathing chest, robot's joint, and so forth. The flexible wave-shaped strain sensor has great promising applications for wearable electronics, motion recognition, healthcare, and soft robotics.

Superelastic, Sensitive, and Low Hysteresis Flexible Strain Sensor Based on Wave-Patterned Liquid Metal for Human Activity Monitoring.

In recent decades, cementless implants have been widely used in clinical practice to replace missing organs, to replace damaged or missing bone tissue or to restore joint functionality. However, there remain risks of failure which may have dramatic consequences. The success of an implant depends on its stability, which is determined by the biomechanical properties of the bone-implant interface (BII). The aim of this review article is to provide more insight on the current state of the art concerning the evolution of the biomechanical properties of the BII as a function of the implant's environment. The main characteristics of the BII and the determinants of implant stability are first introduced. Then, the different mechanical methods that have been employed to derive the macroscopic properties of the BII will be described. The experimental multi-modality approaches used to determine the microscopic biomechanical properties of periprosthetic newly formed bone tissue are also reviewed. Eventually, the influence of the implant's properties, in terms of both surface properties and biomaterials, is investigated. A better understanding of the phenomena occurring at the BII will lead to (i) medical devices that help surgeons to determine an implant's stability and (ii) an improvement in the quality of implants.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2019.0259

Biomechanical behaviours of the bone–implant interface: a review

/pdf/a-magnetically-coupled-dielectric-elastomer-pump-for-soft-5tvdhqllch.pdf

A Magnetically Coupled Dielectric Elastomer Pump for Soft Robotics

Superhydrophobic surfaces repel water and other liquids such as tissue fluid, blood, urine, and pus, which can open up a new avenue for the development of biomedical devices and has led to promising advances across diverse fields, including plasma separator devices, blood-repellent sensors, vascular stents, and heart valves. Here, the fabrication of superhydrophobic liquid-solid contact triboelectric nanogenerators (TENGs) and their biomedical applications as droplet sensors are reported. Triboelectrification energy can be captured and released when droplets are colliding or slipping on the superhydrophobic layer. The developed superhydrophobic TENG possesses multiple advantages in terms of simple fabrication, bendability, self-cleaning, self-adhesiveness, high sensitivity, and repellency to not only water but also a variety of solutions, including blood with a contact angle of 158.6°. As a self-powered sensor, the developed prototypes of a drainage bottle droplet sensor and a smart intravenous injection monitor based on the superhydrophobic liquid-solid contact TENG can monitor the clinical drainage operation and intravenous infusion in real time, respectively. These prototypes suggest the potential merit of this superhydrophobic liquid-solid contact TENG in clinical application, paving the way for accurately monitoring clinical drainage operations and intravenous injection or blood transfusion in the future.

Xing Gao

Papers

Electroconductive natural polymer-based hydrogels.

Superelastic, Sensitive, and Low Hysteresis Flexible Strain Sensor Based on Wave-Patterned Liquid Metal for Human Activity Monitoring.

Biomechanical behaviours of the bone–implant interface: a review

A Magnetically Coupled Dielectric Elastomer Pump for Soft Robotics

Superhydrophobic Liquid-Solid Contact Triboelectric Nanogenerator as a Droplet Sensor for Biomedical Applications.