A Novel Targeting Drug Delivery System Based on Self-Assembled Peptide Hydrogel

In the last two decades, 5-fluorouracil (5-FU) is widely used in clinical practice to inhibit the fibroblasts to proliferate and improve the success rate of glaucoma-filtering surgery, but 5-FU has many toxic effects to normal ocular tissues. The self-assembled peptide hydrogels may serve as a new class of biomaterials for applications including tissue engineering and drug delivery. How to deliver 5-FU quickly and precisely to the target sites of ocular tissue by a self-assembled peptide hydrogel remains unexplored. RGD (arginine-glycine-aspartic acid) sequence is cell attachment site in extracellular matrix (ECM). Thus, If the self-assembled peptide hydrogel containing the RGD sequence that act as a specific attachment site for the proliferated fibroblasts adhesion could be designed, after integrated 5-FU, a novel targeting drug delivery system will be put into practice in the future.

Magnetic field-assisted microbial corrosion construction iron sulfides incorporated nickel-iron hydroxide towards efficient oxygen evolution

Nickel iron(hydroxyl)hydroxide with unique layered structure and controllable composition is widely regarded as typical oxygen evolution reaction(OER)catalysts.Recently,developing top-down approaches to realize the facile preparation of transition metal hydroxide catalyst has received wide attention.Based on the natural microorganism corrosion behavior,this work demonstrates the external magnetic field-assisted microbial corrosion strategy to construct advanced transition metal hydroxide OER catalyst,and the prepared biofilm electrode presents superior OER performance in the existence of magnetic field,which needs an overpotential of 287 mV at 100 mA cm^(-2).Experimental and theoretical calculations show the applied magnetic field can accelerate sulfate reducing bacteria(SRB)corrosion and chemical corrosion.The additional magnetic field can promote SRB corrosion to produce FeS,which can facilitate the optimization of O intermediate desorption from the NiOOH catalyst during OER process,reducing the reaction energy barrier for O→OOH.The synergistic effect between the nickel-iron oxyhydroxides originated from the accelerated chemical corrosion and FeS produced from the accelerated SRB corrosion interprets the improved OER activity.This work explores the influence of magnetic field on the construction of advanced OER materials,which can provide an effective magnetic field-assisted corrosion engineering strategy,and promote the development of multidisciplinary fields of physics,biology,and emerging energy conversion technologies.

Precise nanomedicine for intelligent therapy of cancer

Precise nanomedicine has been extensively explored for efficient cancer imaging and targeted cancer therapy, as evidenced by a few breakthroughs in their preclinical and clinical explorations. Here, we demonstrate the recent advances of intelligent cancer nanomedicine, and discuss the comprehensive understanding of their structure-function relationship for smart and efficient cancer nanomedicine including various imaging and therapeutic applications, as well as nanotoxicity. In particular, a few emerging strategies that have advanced cancer nanomedicine are also highlighted as the emerging focus such as tumor imprisonment, supramolecular chemotherapy, and DNA nanorobot. The challenge and outlook of some scientific and engineering issues are also discussed in future development. We wish to highlight these new progress of precise nanomedicine with the ultimate goal to inspire more successful explorations of intelligent nanoparticles for future clinical translations.

Environmentally responsive dual-targeting nanotheranostics for overcoming cancer multidrug resistance

The development of multiple drug resistance(MDR) to chemotherapy and subsequent treatment failures are major obstacles in cancer therapy. An attractive option for combating MDR is inhibiting the expression of P-glycoprotein(P-gp) in tumor cells. Here, we report a novel chemosensitizing agent, XMD8-92,which can down-regulate P-gp. To enhance the specificity of MDR chemotherapy, a promising nanotheranostic micelle system based on poly(ethylene glycol)-blocked-poly(L-leucine)(PEG-b-Leu) was developed to simultaneously carry the anticancer drug doxorubicin, chemosensitizing agent XMD8-92, and superparamagnetic iron oxide nanoparticles(SPIOs). Featured with MDR environmentally responsive dual-targeting capability, controllable drug delivery, and efficient magnetic resonance(MR) imaging characteristics, the prepared nanotheranostics(DXS@NPs) showed outstanding in vitro cytotoxicity on MDR cells(SCG 7901/VCR) with only 53% of cells surviving compared to 90% of DOX-treated cells.Furthermore, efficient tumor inhibition and highly reduced systemic toxicity were exhibited by MDR tumor-bearing mice treated with DXS@NPs. Overall, the environmentally responsive dual-targeting nanotheranostics represent a promising approach for overcoming cancer MDR.

Self-delivery of a peptide-based prodrug for tumor- targeting therapy

A novel self-delivered prodrug system was fabricated for tumor-targeting therapy. In this nanosystem, the Arg-Gly-Asp-Ser （RGDS） tetrapeptide was used to improve the therapeutic index to integrin-overexpressing tumor cells. The antitumorous drug camptothecin was further appended to the ε-amino group of lysine by 20-O-succinyl linkage and controllably released via hydrolytic cleavage. Prodrug molecules self-assembled into fibrillar nano-architectures and achieved the capability of self-delivery after being injected subcutaneously into mice. Introduction of hydrophobic myristic add favored the self-assembly and enhanced the cellular internalization of the prodrugs. In vitro and in vivo studies demonstrated that the self-assembled nanofibers could effectively target integrin- overexpressing tumorous cells and inhibit tumor growth via RGD-mediated specific targeting. Therefore, the traditional idea that fibrillar structures hold low therapeutic efficacy due to poor cell uptake can be challenged.

Polymeric prodrug for bio-controllable gene and drug co-delivery

A polymeric polyethylenimine(PEI)-based prodrug of anticancer doxorubicin(DOX)(PEI-hyd-DOX) was designed by attaching DOX to PEI via an acid-labile hydrazone bond, for the achievement of biocontrollable gene and drug co-delivery in response to the intracellular acid microenvironments in the late endosome/lysosome compartments. The cytotoxicity of PEI-hyd-DOX was evaluated by the MTT assay and the cellular uptake was monitored using confocal laser scanning microscopy. The polymeric prodrug can respond with a high sensitivity to the specific acid condition inside cells, thus permitting the precise biocontrol over intracellular drug liberation with high drug efficacy. The chemical attachment of drug molecules also led to the relatively reduced toxicity and the enhanced transfection efficiency compared with parent PEI. The resulting data adumbrated the potential of PEI-hyd-DOX to co-deliver DOX and therapeutic gene for the combination of chemotherapy and gene therapy.

Flexible-on-rigid heteroepitaxial metal-organic frameworks induced by template lattice change

Hybrid-phase metal-organic frameworks(MOFs)are a class of intriguing heterostructures for diverse applications,the properties of which are governed by their chemical composition,framework topology,and morphology.Herein,we report the structural and morphological evolution of flexible MOFs induced by the lattice change of template during heteroepitaxial growth.We demonstrate that the epitaxially grown flexible Fe-MOFs can be varied from one structure to another to adapt to the lattice of the template Zr-MOFs.Thus,flexible Fe-MOFs with similar chemical compositions and topology can be epitaxially grown on different Zr-MOFs over huge lattice constant gradient.We also demonstrate that the morphology of the heterostructures is affected by the degree of lattice difference between the template MOFs and the epitaxial MOFs.The reported results could pave the way toward the rational design of hybrid-phase MOFs guided by the principles of reticular chemistry.