Vascular systems are responsible for various physiological and pathological processes related to all organs in vivo, and the survival of engineered tissues for enough nutrient supply in vitro. Thus, biomimetic vascularization is highly needed for constructing both a biomimetic organ model and a reliable engineered tissue. However, many challenges remain in constructing vascularized tissues, requiring the combination of suitable biomaterials and engineering techniques. In this review, the advantages of hydrogels on building engineered vascularized tissues are discussed and recent engineering techniques for building perfusable microchannels in hydrogels are summarized, including micromolding, 3D printing, and microfluidic spinning. Furthermore, the applications of these perfusable hydrogels in manufacturing organ‐on‐a‐chip devices and transplantable engineered tissues are highlighted. Finally, current challenges in recapitulating the complexity of native vascular systems are discussed and future development of vascularized tissues is prospected.

The development of high‐efficiency nanozymes is of great significance in the field of nanozymology, because this is one of the prerequisites for the sophisticated performance of nanozymes. Herein, the developed metal–ligand cross‐linking strategy engineers porous carbon nanorod supported ultra‐small iron carbide nanoparticles that possess excellent oxidase‐like and peroxidase‐like enzyme activities. The fabricated nanozyme can efficiently accelerate the oxidation of ascorbate (AA) to enhance cancer cells ablation efficacy. Due to the nanozyme having great surface atoms utilization ratio and large specific surface area, the AA can be rapidly and completely autoxidized within 20 min. Mechanism research demonstrates that the nanozyme's first activation of O2 to generate superoxide free radicals (O2•−) via the oxidase‐like pathway, then the O2•− directly oxidizes AA and produces hydrogen peroxide (H2O2). Simultaneously, the H2O2 transforms into the toxic hydroxyl radical through the peroxidase‐like pathway and induces tumor cell death. Further in vitro and in vivo assays show the significant enhancement of the anti‐tumor efficacy through AA oxidation which is catalyzed by the developed nanozyme. It is expected that this work will benefit not only the development of other efficient nanozymes, but also future advances in the field of AA oxidation induced tumor therapy.

Unprecedented advances in metal nanoparticle synthesis have paved the way for broad applications in sensing, imaging, catalysis, diagnosis and therapy by tuning optical properties, enhancing catalytic performance, and improving chemical and biological properties of metal nanoparticles. The central guiding concept for regulating the size and morphology of metal nanoparticles has been identified as the precise manipulation of nucleation and subsequent growth, often known as seed‐mediated growth methods. However, since the growth process is sensitive not only to the metal seeds but also to capping agents, metal precursors, growth solution, growth/incubation time, reductant and other influencing factors, the precise control of metal nanoparticle morphology is multifactorial. Further, multiple reaction parameters are entangled with each other, so it is necessary to clarify the mechanism by which each factor precisely regulates the morphology of metal nanoparticles. In this review, to exploit the generality and extendibility of metal nanoparticle synthesis, we systematically summarized the mechanism of growth influencing factors in seed‐mediated growth methods. Second, we focus on a variety of critical properties and applications enabled by grown metal nanoparticles. Finally, we review the current progress and offer insights on the challenges, opportunities, and future directions for the growth and applications of grown metal nanoparticles.This article is protected by copyright. All rights reserved

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