Acid‐sensitive reactive oxygen species triggered dual‐drug delivery systems for chemo‐photodynamic therapy to overcome multidrug resistance

Cu2+/Zn2+ "Antimicrobial Chamber" with Self-Enhanced Photothermal Activity Supports Infected Wound Healing

Wound healing of drug-resistant bacterial infection is a major challenge in clinical practice, and existing treatments suffer from the drawbacks of high dosage, low efficiency, and insufficient biosafety. Herein, we coated ultrasmall copper sulfide nanoparticles (CuS NPs) into zeolitic imidazolate framework-8 (ZIF-8) and modified them with polydopamine (PDA) to obtain CuS@ZIF-8@PDA NPs for bacterial infection wound treatment. Due to the presence of CuS and the degradability of ZIF-8, CuS@ZIF-8@PDA NPs can continuously release Cu2+ and Zn2+ in a slightly acidic environment under near-infrared (NIR) irradiation. Furthermore, the introduction of PDA endows it with an excellent photothermal property. The synergistic effect of dual ions/photothermal enables it to effectively eradicate Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Moreover, in vivo experimental results confirm that released Cu2+ and Zn2+ can promote epithelial regeneration, thereby accelerating wound healing. In the bacterially infected mouse model, CuS@ZIF-8@PDA NPs exhibit excellent synergistic antimicrobial and wound healing effects, while having no toxic side effects on major organs. The study of the dual-ion/photothermal synergistic antibacterial strategy based on CuS@ZIF-8@PDA NPs provides a new insight into bacterial infection wound repair.

Advances in the application of metal oxide nanozymes in tumor detection and treatment

Natural enzymes play an important role to support the regular life activities of the human body. However, the application conditions of natural enzymes are harsh and there are limitations in their use. As artificial enzymes, nanozymes possess the substrate specificity of natural enzymes. Due to the advantages of low cost, good stability and strong catalytic properties, nanozymes hold a wide range of applications in the fields of sensing, chemical, food and medicine. Some of the more common ones are noble metal nanozymes, metal oxide nanozymes and carbon-based nanozymes. Among them, metal oxide nanozymes have attracted much attention because of their decent fixity, exceedingly good physicochemical properties and other advantages. Today, malignant tumors pose a great danger to the human body and are a serious threat to human health. However, traditional treatments have more side effects, and finding new treatment modalities is particularly important for tumor treatment. For example, enzyme therapy can be used to catalyze reactions in the body to achieve tumor treatment. Nanozymes can exert enzymatic activity and effectively treat malignant tumors through catalysis and synergy, and have made certain progress. This paper reviews the detection and application of metal oxide nanozymes in tumor detection and treatment in recent years and provides an outlook on their future application and development.

Surface charge switchable nano-micelle for pH/redox-triggered and endosomal escape mediated co-delivery of doxorubicin and paclitaxel in treatment of lung adenocarcinoma

Recently, the stimulus-sensitive drug co-delivery system has gained increasing attentions in the clinic and exhibits improved efficiency rather than the mono-chemotherapy in anti-tumor therapy. Herein, the smart charge switchable nano-micelles (NMs) were fabricated for the endosomal escape mediated co-delivery of doxorubicin (DOX) and paclitaxel (PTX) in treatment of lung adenocarcinoma. The disulfide bonds were facilitated as the linker of the polymer backbone to achieve the redox-sensitive degradation by high intracellular GSH, and acid-liable DMMA was grafted onto DOX molecules for pH-triggered drug release under acidic tumoral microenvironment. Folic acid (FA) was utilized as targeting molecule for facilitating entry of the as prepared NMs into cancer cells. Remarkably, the as fabricated NMs exhibited surface charge-switch from negative to positive during transmitting from physiological pH to the tumor extracellular pH, which can improve the cellular internalization towards cancer cell. Subsequently, the "proton-sponge" effect mediated endosome escape of the NMs was facilitated in the acidic endo/lysosome environment. By the cell assay, the NMs possessed good biocompatibility, excellent cellular uptake, and improved inhibition rate against cancer cell. Moreover, the co-delivery of DOX/PTX exhibited synergistic and enhanced solid tumor inhibition efficiency comparing to mono-chemotherapy in A-549 tumor bearing mice model. Based on above experimental results, the as prepared drug co-delivery system showed promising biosafety and potentials for efficient lung adenocarcinoma treatment in clinic.

Controlled Bioactive Delivery Using Degradable Electroactive Polymers

Biomaterials capable of precisely controlling the delivery of agrochemicals/biologics/drugs/fragrances have significant markets in the agriscience/healthcare industries. Here, we report the development of degradable electroactive polymers and their application for the controlled delivery of a clinically relevant drug (the anti-inflammatory dexamethasone phosphate, DMP). Electroactive copolymers composed of blocks of polycaprolactone (PCL) and naturally occurring electroactive pyrrole oligomers (e.g., bilirubin, biliverdin, and hemin) were prepared and solution-processed to produce films (optionally doped with DMP). A combination of in silico/in vitro/in vivo studies demonstrated the cytocompatibility of the polymers. The release of DMP in response to the application of an electrical stimulus was observed to be enhanced by ca. 10–30% relative to the passive release from nonstimulated samples in vitro. Such stimuli-responsive biomaterials have the potential for integration devices capable of delivering a variety of molecules for technical/medical applications.

Micelles Based on Lysine, Histidine, or Arginine: Designing Structures for Enhanced Drug Delivery

Natural amino acids and their derivatives are excellent building blocks of polymers for various biomedical applications owing to the non-toxicity, biocompatibility, and ease of multifunctionalization. In the present review, we summarized the common approaches to designing and constructing functional polymeric micelles based on basic amino acids including lysine, histidine, and arginine and highlighted their applications as drug carriers for cancer therapy. Different polypeptide architectures including linear polypeptides and dendrimers were developed for efficient drug loading and delivery. Besides, polylysine- and polyhistidine-based micelles could enable pH-responsive drug release, and polyarginine can realize enhanced membrane penetration and gas therapy by generating metabolites of nitric oxide (NO). It is worth mentioning that according to the structural or functional characteristics of basic amino acids and their derivatives, key points for designing functional micelles with excellent drug delivery efficiency are importantly elaborated in order to pave the way for exploring micelles based on basic amino acids.