3D-printed tissue repair patch combining mechanical support and magnetism for controlled skeletal muscle regeneration

Physical forces,such as magnetic and mechanical stimulation,are known to play a significant role in the regulation of cell response.In the present study,a biomimetic regeneration patch was fabricated using E-jet 3 D printing,which integrates mechanical and magnetic stimulation in a biocompatible"one-pot reaction"strategy when combined with a static magnetic field(SMF).The magneto-based therapeutic regeneration patch induced myoblasts to form aligned and multinucleated myotubes,regulated the expression of myogenic-related genes,and activated the p38αmitogen-activated protein kinase pathway via the initiation of myogenic differentiation.To validate the efficiency of the proposed strategy,the regeneration patch was implanted into mice and exposed to a suitable SMF,which resulted in significantly enhanced in vivo skeletal muscle regeneration.The findings demonstrated that appropriate external physical stimulation provides a suitable biophysical microenvironment that is conducive to tissue regeneration.The method used in the present study represents a promising technique to induce the regeneration of damaged skeletal muscle tis sue.

Bioadaptability:An Innovative Concept for Biomaterials

Biocompatibility is the basic requirement of biomaterials for tissue repair. However, the present concept of biocompatibility has a certain limitation in explaining the phenomena involved in biomaterial-based tissue repair. New materials, in particular those for tissue engineering and regeneration, have been developed with common characteristics, i.e. they participate deeply into important chemical and biological processes in the human body and the interaction between the biomaterials and tissues is far more complex. Understanding the interplay between these biomaterials and tissues is vital for their development and functionalization. Herein, we suggest the concept of bioadaptability of biomaterials. This concept describes the three most important aspects that can determine the performance of biomaterials in tissue repair： 1） the adaptability of the micro-environment created by biomaterials to the native microenvironment in situ; 2） the adaptability of the mechanical properties of biomaterials to the native tissue; 3） the adaptability of the degradation properties of biomaterials to the new tissue formation. The concept of bioadaptability emphasizes both the material＇s characteristics and biological aspects within a certain micro-environment and molecular mechanism. It may provide new inspiration to uncover the interaction mechanism of biomaterials and tissues, to foster the new ideas of functionalization of biomaterials and to investigate the fundamental issues during the tissue repair process by biomaterials. Furthermore, designing biomaterials with such bioadaptability would open a new door for repairing and regenerating organs or tissues. In this review, we summarized the works in recent years on the bioadaptability of biomaterials for tissue repair applications.

Functional micro/nanobubbles for ultrasound medicine and visualizable guidance

Chemically functionalized gas-filled bubbles with a versatile micro/nano-sized scale have witnessed a long history of developments and emerging applications in disease diagnosis and treatments.In combination with ultrasound and image-guidance,micro/nanobubbles have been endowed with the capabilities of biomedical imaging,drug delivery,gene transfection and diseaseoriented therapy.As an external stimulus,ultrasound(US)-mediated targeting treatments have been achieving unprecedented efficiency.Nowadays,US is playing a crucial role in visualizing biological/pathological changes in lives as a reliable imaging technique and a powerful therapeutic tool.This review retrospects the history of ultrasound,the chemistry of functionalized agents and summarizes recent advancements of functional micro/nanobubbles as US contrast agents in preclinical and transclinical research.Latest ultrasound-based treatment modalities in association with functional micro/nanobubbles have been highlighted as their great potentials for disease precision therapy.It is believed that these state-of-the-art micro/nanobubbles will become a booster for ultrasound medicine and visualizable guidance to serve future human healthcare in a more comprehensive and practical manner.