Dimeric Her2-specific affibody mediated cisplatin-loaded nanoparticles for tumor enhanced chemo-radiotherapy.

BACKGROUND: Solid tumor hypoxic conditions prevent the generation of reactive oxygen species (ROS) and the formation of DNA double-strand breaks (DSBs) induced by ionizing radiation, which ultimately contributes to radiotherapy (RT) resistance. Recently, there have been significant technical advances in nanomedicine to reduce hypoxia by facilitating in situ O2 production, which in turn serves as a "radiosensitizer" to increase the sensitivity of tumor cells to ionizing radiation. However, off-target damage to the tumor-surrounding healthy tissue by high-energy radiation is often unavoidable, and tumor cells that are further away from the focal point of ionizing radiation may avoid damage. Therefore, there is an urgent need to develop an intelligent targeted nanoplatform to enable precise enhanced RT-induced DNA damage and combined therapy. RESULTS: Human epidermal growth factor receptor 2 (Her2)-specific dimeric affibody (ZHer2) mediated cisplatin-loaded mesoporous polydopamine/MnO2/polydopamine nanoparticles (Pt@mPDA/MnO2/PDA-ZHer2 NPs) for MRI and enhanced chemo-radiotherapy of Her2-positive ovarian tumors is reported. These NPs are biodegradable under a simulated tumor microenvironment, resulting in accelerated cisplatin release, as well as localized production of O2. ZHer2, produced using the E. coli expression system, endowed NPs with Her2-dependent binding ability in Her2-positive SKOV-3 cells. An in vivo MRI revealed obvious T1 contrast enhancement at the tumor site. Moreover, these NPs achieved efficient tumor homing and penetration via the efficient internalization and penetrability of ZHer2. These NPs exhibited excellent inhibition of tumor growth with X-ray irradiation. An immunofluorescence assay showed that these NPs significantly reduced the expression of HIF-1α and improved ROS levels, resulting in radiosensitization. CONCLUSIONS: The nanocarriers described in the present study integrated Her2 targeting, diagnosis and RT sensitization into a single platform, thus providing a novel approach for translational tumor theranostics.

Preparation, function, and safety evaluation of a novel degradable dermal filler, the cross-linked poly-γ-glutamic acid hydrogel particles.

Poly-γ-glutamic acid (PGA) is a naturally degradable hydrophilic linear microbial polymer with moisturizing, immunogenic, cross-linking, and hydrogel water absorption properties similar to hyaluronic acid, a biomaterial that is commonly used as a dermal filler. To explore the development feasibility of cross-linked PGA as a novel dermal filler, we studied the local skin response to PGA fillers and the effect of various cross-linking preparations on the average longevity of dermal injection. Injection site inflammation and the formation of collagen and elastin were also determined. PGA hydrogel particles prepared using 28% PGA and 10% 1,4-butanediol diglycidyl ether showed optimal filler properties, resistance to moist heat sterilization, and an average filling longevity of 94.7 ± 61.6 days in the dermis of rabbit ears. Local redness and swelling due to filler injection recovered within 14.2 ± 3.6 days. Local tissue necrosis or systemic allergic reactions were not observed, and local collagen formation was promoted. Preliminary results suggested that dermal injection of cross-linked PGA particles appeared safe and effective, suggesting that cross-linked PGA particles could be developed as a new hydrogel dermal filler.

Electrospun nanofibers for bone regeneration: from biomimetic composition, structure to function.

In recent years, a variety of novel materials and processing technologies have been developed to prepare tissue engineering scaffolds for bone defect repair. Among them, nanofibers fabricated via electrospinning technology have attracted much interest owing to the unique feature of highly mimicking the natural bone extracellular matrix. In particular, many achievements have been made in this field over the past several years. Therefore, this review aims to summarize the most recent advances and highlights of electrospun nanofibers in bone regeneration applications, by focusing on their material compositions (synthetic polymers, natural polymers, composite nanofibers, and hybrid nanofibers), structural regulation strategies (aligned structures, core-shell structures, gradient structures, and three-dimensional structures), function regulation achievements (biomineralization, osteogenesis, vascularization, immunomodulatory, and anti-infection), and combination with other emerging scaffold fabrication technologies (3D printing, electrospraying, and microfluidics). Finally, the future challenges of nanofibrous scaffolds in this field are also discussed briefly. It is anticipated that this review will provide useful insights into the future development of nanofibrous scaffolds in tissue engineering and bone regeneration applications.