This review summarized the recent progress in the synthesis, characterization, properties, photoluminescence mechanism and biological applications of carbon dots.

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Exosomes, the smallest subgroup of extracellular vesicles, have been recognized as extracellular organelles that contain genetic and proteomic information for long distance intercellular communication. Exosome-based drug delivery is currently a subject of intensive research. Here, we report a novel strategy to produce nanoscale exosome-mimics (EMs) in sufficient quantity for gene delivery in cancer both in vitro and in vivo. Size-controllable EMs were generated at a high yield by serial extrusion of non-tumorigenic epithelial MCF-10A cells through filters with different pore sizes. siRNA was then encapsulated into the EMs by electroporation. Biosafety and uptake efficiency of the EMs were evaluated both in vitro and in vivo. The mechanism underlying their cellular endocytosis was also studied.

Of great interest to modern medicine and biomedical research is the ability to inject individual target cells with the desired genes or drug molecules. Some advances in cell electroporation allow for high throughput, high cell viability, or excellent dosage control, yet no platform is available for the combination of all three. In an effort to solve this problem, here we show a "3D nano-channel electroporation (NEP) chip" on a silicon platform designed to meet these three criteria. This NEP chip can simultaneously deliver the desired molecules into 40,000 cells per cm(2) on the top surface of the device. Each 650 nm pore aligns to a cell and can be used to deliver extremely small biological elements to very large plasmids (>10 kbp). When compared to conventional bulk electroporation (BEP), the NEP chip shows a 20 fold improvement in dosage control and uniformity, while still maintaining high cell viability (>90%) even in cells such as cardiac cells which are characteristically difficult to transfect. This high-throughput 3D NEP system provides an innovative and medically valuable platform with uniform and reliable cellular transfection, allowing for a steady supply of healthy, engineered cells.

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Double network (DN) hydrogels, a kind of promising soft and tough hydrogels, are produced by two unique contrasting networks with designed network entanglement burst into the field of materials science as versatile functional systems for a very broad range of applications. A part of the DN hydrogels is characterized by extraordinary mechanical properties providing efficient biocompatible and high strength for holding considerable promise in tissue engineering. Following DN hydrogels principles and consideration of biomedical applications, we provide an overall view of the present various DN hydrogels and look forward to the future of DN hydrogels for tissue engineering. In this review, the preparation methods, structure, properties, current situation, and challenges are mainly discussed for the purpose of tissue engineering. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement.

The significant influence of graphene oxide (GO) on the unidirectional foaming of poly(lactic acid) (PLA) using supercritical CO 2 as blowing agent was investigated in this study for the first time. Highly oriented and elongated cell structures were obtained from the PLA/GO nanocomposites foams. The thermal, rheological, and CO 2 absorption properties of the PLA/ GO nanocomposites were studied to investigate the effect of GO on PLA unidirectional foaming. It was found that the incorporation of GO improved the storage modulus, loss modulus, and complex viscosity of the PLA/GO nanocomposites significantly. The addition of GO improved the CO 2 absorption ability of the nanocomposites, which caused high expansion ratio and increased average cell size during foaming process. The high expansion force by enhanced CO 2 absorption, high matrix viscosity of PLA/GO nanocomposites, and restriction of the mold in three directions together caused the formation of the highly elongated cell structure during foaming.

Nanomaterials provide a viable potential diagnosis mechanis. In the future, more research needs to be focused on developing a better diagnosis tool for detection of cancer on an urgent basis. Blood-brain barrier and cytotoxicity are some of the primary root causes for the impediment of treatment of cancer using nanoparticles. Therefore, different delivery systems should be exploited for the nanoparticles to surmount these issues.