A universal biocompatible coating for enhanced lubrication and bacterial inhibition.

Antibacterial coatings that inhibit bacterial adhesion are essential for many implanted medical devices. A variety of antibacterial strategies, such as repelling or killing bacteria, have been developed, but not yet been completely successful. Here, we develop a universal biocompatible coating for enhanced lubrication and bacterial inhibition. The coating is designed based on mussel-inspired surface-attachable dopamine bases and consists of lubricating zwitterionic polymers poly(2-methacryloxyethyl phosphorylcholine) (MPC) and a bacterial membrane destroying anti-bacteria molecule poly(3-hydroxybutyric acid) (PHB). The coating boasts strong adhesion to surfaces of various materials (such as polydimethylsiloxane (PDMS)/ceramic/316L stainless steel (316L SS); it is biocompatible, and cell/platelet/bacteria repelling, significantly inhibiting bacterial growth. We envision that our strategy represents a universal strategy for surface functionalization of a variety of biomedical devices and implants.

pH-Triggered Copper-Free Click Reaction-Mediated Micelle Aggregation for Enhanced Tumor Retention and Elevated Immuno-Chemotherapy against Melanoma.

Natural killer (NK) cell-based immunotherapy presents a promising antitumor strategy and holds potential for combination with chemotherapy. However, the suppressed NK cell activity and poor tumor retention of therapeutics hinder the efficacy. To activate NK cell-based immuno-chemotherapy and enhance the tumor retention, we proposed a pH-responsive self-aggregated nanoparticle for the codelivery of chemotherapeutic doxorubicin (DOX) and the transforming growth factor-ß (TGF-ß)/Smad3 signaling pathway inhibitor SIS3. Polycaprolactone-poly(ethylene glycol) (PCL-PEG2000) micelles modified with dibenzylcyclooctyne (DBCO) or azido (N3) and coated with acid-cleavable PEG5000 were established. This nanoplatform, namely, M-DN@DOX/SIS3, could remain well dispersed in the neutral systemic circulation, while quickly respond to the acidic tumor microenvironment and intracellular lysosomes, triggering copper-free click reaction-mediated aggregation, leading to the increased tumor accumulation and reduced cellular efflux. In addition, the combination of DOX with SIS3 facilitated by the aggregation strategy resulted in potent inhibition of melanoma tumor growth and significantly increased NK cells, NK cell cytokines, and antitumor T cells in the tumor. Taken together, our study offered a new concept of applying copper-free click chemistry to achieve nanoparticle aggregation and enhance tumor retention, as well as a promising new combined tumor treatment approach of chemotherapy and immunotherapy.

Effective treatment of the primary tumor and lymph node metastasis by polymeric micelles with variable particle sizes.

Nanoparticles (NPs) offer new solutions for the diagnosis and treatment of tumors. However, the anti-tumor effect has not been greatly improved. Tumors are easily spread through the lymphatic system while the traditional NPs (~100 nm) can hardly reach lymph nodes for the treatment of metastasis. In addition, the NPs with fixed particle size cannot achieve efficient "penetration" and long-term "retention" simultaneously. Herein, we established "transformable" micelles modified with azide/alkyne groups for click chemical reaction. Not surprisingly, the small micelles (~25 nm) could effectively target lymph nodes, limiting the growth of the metastases associated with their size-regulated abilities to extravasate from the vasculature. Tumor lymph node metastasis dropped by 66.7%. After reaching primary tumors, cycloaddition reaction occurred between groups on micelles, resulting in the formation of aggregates. The strategy resulted in improved retention of the micelles in 4 T1 cells both in vitro and in vivo owing to the decreasing of nanoparticle exocytosis and minimizing the backflow to the bloodstream. Enhanced cytotoxicity on 4 T1 cells and improved antitumor efficacy were also observed. S-PTX (+) exhibited 76.23% tumor suppression, and tumor mass at the end of the treatment also showed the best tumor inhibitory effect. In conclusion, this drug delivery system provides a strategy for effective treatment of the primary tumor and lymphatic metastasis.

Dual receptor recognizing liposomes containing paclitaxel and hydroxychloroquine for primary and metastatic melanoma treatment via autophagy-dependent and independent pathways.

Autophagy acts as a cytoprotective mechanism for malignant tumors, thus maintaining the survival and promoting proliferation and metastasis of malignant tumors. Recent studies have showed that autophagy inhibitors can enhance the chemotherapeutic efficacy of anti-tumor growth. However, the antimetastasis effects and the possible mechanisms of chemotherapeutics combined with autophagy inhibitors have not been thoroughly explored. Here, we prepared R8-dGR peptide modified paclitaxel (PTX) and hydroxychloroquine (HCQ) co-loaded liposomes (PTX/HCQ-R8-dGR-Lip) for enhanced delivery by recognizing integrin αvß3 receptors and neuropilin-1 receptors on B16F10 melanoma cells. Our results showed that R8-dGR modified liposomes (R8-dGR-Lip) enhanced tumor-targeting delivery in vitro and in vivo. Besides, PTX/HCQ-R8-dGR-Lip exhibited the optimum inhibitory effects on migration, invasion and anoikis resistance of B16F10 cells in vitro, and showed enhanced efficiency on inhibiting primary tumor growth and reducing lung metastasis in vivo. Meanwhile, the antimetastasis mechanism studies confirmed that the combination of the chemotherapeutic PTX and the autophagy inhibitor HCQ further suppressed the degradation of paxillin, the expression of MMP9 and MMP2. Moreover, HCQ disturbed the CXCR4/CXCL12 axis which could induce invasion and metastasis of malignant melanoma in an autophagy-independent way.