Nano Ag@bioactive microspheres from marine sponge Clathria frondifera: Fabrication, fortification, characterization, anticancer and antibacterial potential evaluation

Elastin-like recombinamer-mediated hierarchical mineralization coatings on Zr-16Nb-xTi (x = 4,16 wt%) alloy surfaces improve biocompatibility

The biocompatibility of biomedical materials is vital to their applicability and functionality. However, modifying surfaces for enhanced biocompatibility using traditional surface treatment techniques is challenging. We employed a mineralizing elastin-like recombinamer (ELR) self-assembling platform to mediate mineralization on Zr-16Nb-xTi (x = 4,16 wt%) alloy surfaces, resulting in the modification of surface morphology and bioactivity while improving the biocompatibility of the material. We modulated the level of nanocrystal organization by adjusting the cross-linker ratio. Nanoindentation tests revealed that the mineralized configuration had nonuniformity with respect to Young's modulus and hardness, with the center areas having higher values (5.626 ± 0.109 GPa and 0.264 ± 0.022 GPa) compared to the edges (4.282 ± 0.327 GPa and 0.143 ± 0.023 GPa). The Scratch test results indicated high bonding strength (2.668 ± 0.117 N) between the mineralized coating and the substrate. Mineralized Zr-16Nb-xTi (x = 4,16 wt%) alloys had higher viability compared to untreated alloys, which exhibited high cell viability (>100 %) after 5 days and high alkaline phosphatase activity after 7 days. Cell proliferation assays indicated that MG 63 cells grew faster on mineralized surfaces than on untreated surfaces. Scanning electron microscopy imaging confirmed that the cells adhered and spread well on mineralized surfaces. Furthermore, hemocompatibility test results revealed that all mineralized samples were non-hemolytic. Our results demonstrate the viability of employing the ELR mineralizing platform to improve alloy biocompatibility.

Plasmid containing VEGF-165 and ANG-1 dual genes packaged with fibroin-modified PEI to promote the regeneration of vascular network and dermal tissue

Reducing the cytotoxicity of cationic polymers is the major issue to their use as a gene delivery carrier. In this study, plasmids containing encoding vascular endothelial cell growth factor 165 and angiopoietin-1 were packaged with the conjugates of cationic fibroin (CSF) and polyethylenimine (PEI), instead of packaging pDNA with PEI alone, to prepare nanocomplexes (CSF+PEI)/pDNA. The complexes were loaded into a silk fibroin scaffold to enhance its function to induce microvascular network generation and dermal tissue regeneration. The results of transfecting EA.hy926 cells with the complexes in vitro showed that (CSF+PEI)/pDNA had a stronger transfection ability than PEI/pDNA. Importantly, compared with PEI as the gene carrier alone, the cell viability was significantly increased and the cytotoxicity was effectively reduced after the conjugate of CSF and PEI was used as the gene carrier. The results of angiogenesis in chick embryo chorioallantoic membranes showed that compared with scaffolds loaded with PEI/pDNA, the neovascularization ratio in scaffolds loaded with (CSF+PEI)/pDNA was significantly increased. In vivo experimental results of scaffolds implantation for full-thickness skin defects in SD rats showed that, compared with loading PEI/pDNA complex, loading (CSF+PEI)/pDNA complex in the scaffold more effectively promoted the formation of vascular network in the scaffold and accelerated the regeneration of dermal tissue. The gene delivery system established in this study has application potential not only in the regeneration of vascular-containing tissues, but also in tumor gene therapy.

Role of PSS-based assemblies in stabilization of Eu and Sm luminescent complexes and their thermoresponsive luminescence

The present work introduces self-assembled polystyrenesulfonate (PSS) molecules as soft nanocapsules for incorporation of Eu³⁺-Sm³⁺ complexes by the solvent exchange procedure. The high levels of Eu³⁺- and Sm³⁺-luminescence of the complexes derives from the ligand-to-metal energy transfer, in turn, resulted from the complex formation of Eu³⁺and Sm³⁺ ions with the three recently synthesized cyclophanic 1,3-diketones. The structural features of the ligands are optimized for the high thermal sensitivity of Eu³⁺- luminescence in DMF solutions. The PSS-nanocapsules (∼100 nm) provide both colloid and chemical stabilization of the ultrasmall (3-5 nm) nanoprecipitates of the complexes, although their luminescence spectra patterns and excited state lifetimes differ from the values measured for the complexes in DMF solutions. The specific concentration ratio of the Eu³⁺-Sm³⁺ complexes in the DMF solutions allows to tune the intensity ratio of the luminescence bands at 612 and 650 nm in the heterometallic Eu³⁺-Sm³⁺ colloids. The thermal sensitivity of the Eu³⁺- and Sm³⁺-luminescence of the complexes derives from the static quenching both in PSS-colloids and in DMF solutions, while the thermo-induced dynamic quenching of the luminescence is significant only in DMF solutions. The reversibility of thermo-induced luminescence changes of the Eu³⁺-Sm³⁺ colloids is demonstrated by six heating-cooling cycles. The DLS measurements before and after the six cycles reveal the invariance of the PSS-based capsule as the prerequisite for the recyclability of the temperature monitoring through the ratio of Eu³⁺-to- Sm³⁺ luminescence.