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Zinc-based biometal is expected to become a new generation of biodegradable implants. Due to its antibacterial and biocompatibility in vivo, zinc metals is recently considered to be the most promising biodegradable metal, However, cytotoxicity is the thorny problem that currently restrict its application, due to the excessive Zn ions released during degradation. In order to solve these problems, dopamine modified strontium-doped hydroxyapatite coating (SrHA/PDA) was fabricated on alkali-treated pure zinc to improve its corrosion rate and cytocompatibility by electrodeposition for the first time. The obtained coating showed a dense structure and high crystallinity, which was attributed to the attraction of Ca2+ ions by polydopamine. The results showed that the SrHA/PDA coating delayedthe degradation rate of zinc metal, which reduced the release of Zn2+, thereby reducing its cytotoxicity. Additionally, electrochemical tests showed that SrHA/PDA coating can reduce the corrosion rate of pure zinc. In vitro cell viability showed that even at high Zn2+ concentrations (3.11 mg/L), preosteoblasts (MC3T3-E1) cells proliferated at a high rate on SrHA/PDA, thus confirming that Sr2+ counteracted the cytotoxic effects of Zn2+ and promoted cell differentiation. Moreover, the SrHA/PDA coating still maintained excellent antibacterial effects against pathogenic bacterial strains (Escherichia coli and Staphylococcus aureus). Mild pH changes had no significant effect on the viability of cells and bacterias. Collectively, the present study elucidated that by coating SrHA/PDA/Zn(OH) 2 on Zn, a controllable corrosion rate, original antibacterial properties and better cell compatibility can be achieved. This provided a new strategy for the surface modification of biodegradable Zn. • SrHA/PDA was fabricated on alkali-treated pure zinc. • The SrHA/PDA coating delayed the degradation rate of zinc metal. • The SrHA/PDA coating can reduce the corrosion rate of pure zinc. • The coating had an exceptional antimicrobial effect for S. aureus and E. coli. • The coating showed exceptional cytocompatibility and osseointegration. [ABSTRACT FROM AUTHOR]

Chemotherapy plays crucial roles in the clinical treatment of non-small cell lung cancer (NSCLC). Nevertheless, acquired chemoresistance is a common and critical problem that limits the clinical application of chemotherapy. Quercetin (QUE), a natural bioflavonoid, has significant antitumor potential, which has been verified in many drug-resistant cancer cell lines and animal models. Here, we explored whether QUE could reverse the resistance of NSCLC to paclitaxel (PTX)-based therapy. The results of cell viability revealed that QUE could synergistically enhance the cytotoxicity of PTX in A549 and A549/Taxol cells. Furthermore, Akt and ERK phosphorylation had no significant changes in A549/Taxol cells treated with PTX. However, it was significantly inhibited by the combination treatment of QUE and PTX. To improve the antitumor activity of PTX due to its hydrophobicity and eliminate its toxicity, we prepared targeted biodegradable cetuximab chitosan nanoparticles (Cet-CTS NPs) to deliver PTX and QUE using ionic cross-linking technique. The targeted NPs displayed a particle size of 290 nm and sustained release of PTX and QUE. In addition, the targeted Cet-CTS NPs loaded with PTX and QUE inhibited tumor growth in PTX-resistant A549/Taxol cells. Cet-QUE NPs decreased tumor growth in PTX-resistant xenografts. In conclusion, the administration of QUE by using Cet-CTS NPs could provide a prospective strategy for the treatment of PTX-resistant lung cancer. Schematic illustration of Cet-QUE/PTX NPs preparation and its sequential release process for therapy. In the experiment, we prepared the Cetuximab modified chitosan nanoparticle (Cet-CTS NPs) loaded with Quercetin (QUE) or Paclitaxel (PTX) using ionic cross-linking technique. The synergic effect and reversal influence of co-administration of Cet-CTS NPs with QUE or PTX were evaluated in vitro and in vivo, we found that co-administration of Cet-CTS NPs with QUE and PTX displayed higher killing effect on drug-resistant lung cancer cells via inhibiting the phosphorylation of Akt and ERK. Unlabelled Image • Cet-PTX NPs/Cet-QUE NPs were produced using chitosan bonded Cet for promoting active targeting. • NPs had excellent physicochemical properties which were low size distributions and PDI with positive zeta potential. • Cet-QUE/PTX NPs could synergistically fight against NSCLC and enhance the chemotherapeutic effect of PTX-based therapy. • Cet-QUE NPs could reverse the chemoresistance in PTX-based therapy by inhibiting the phosphorylation of Akt and ERK. [ABSTRACT FROM AUTHOR]

Many studies were conducted to change the surface morphology and chemical composition of Ti implants for the improvement of antibacterial ability and osseointegration between medical Ti and surrounding bone tissue. In this study, we successfully prepared a novel dual-function coating on pure Ti surface, i.e. Cu and Mg-co-doped TiO 2 nanotube (TN) coating, by combining anodisation and hydrothermal treatment (HT), which could act as a delivery platform for the sustained release of Cu and Mg ions. Results showed that the amounts of Cu and Mg were about 5.43 wt%–6.55 wt% and 0.69 wt%–0.73 wt%, respectively. In addition, the surface morphology of Cu and Mg-co-doped TN (CuMTN) coatings transformed into nanoneedles after HT for 1 h. Compared with TN, CuMTN had no change in roughness and remarkable improved hydrophilicity. Antibacterial tests revealed that CuMTN had an antibacterial rate of more than 93% against Escherichia coli and Staphylococcus aureus , thereby showing excellent antibacterial properties. In addition, CuMTN could induce the formation of apatite well after being immersed in simulated body fluid, showing good biological activity. Preosteoblasts (MC3T3-E1) cultured on CuMTN-coated Ti demonstrated better proliferation and osteogenic differentiation than pristine and as-anodised specimens. To the best of our best knowledge, this study had successfully attempted to combine anodisation and HT, introduce Cu/Mg elements and functionalise Ti-based implant surfaces with enhanced hydrophilicity, osteogenesis and antimicrobial properties that can meet clinical needs for the first time. • The copper and magnesium co-doped TN (CuMTN) were prepared. • The nanostructure can slow down the release rate of Mg and Cu. • The coating had an exceptional antimicrobial effect on S. aureus and E. coli. • The coating can induce the formation of new apatite. • The coating showed exceptional cytocompatibility and osseointegration. [ABSTRACT FROM AUTHOR]