Eco-friendly fabricated multibioactive Ca(II)-antibiotic coordination framework coating on zinc towards improved bone tissue regeneration.

Zinc is a biodegradable candidate material for bone regeneration; however, concomitant implant-related infection and rejection require new solutions to raise the biomedical potential of zinc. Functionalization towards localized drug administration with bioactive frameworks can be a solution. It is herein reported for the first time an eco-friendly approach for coating zinc with multibioactive antibiotic coordination frameworks (ACF). ACF1, a new 1D framework with deprotonated nalidixic and salicylic acids, obtained by mechanochemistry, results from the coordination of Ca(II) centers to the organic acids anions. To maximize ACF1 loading and cells' adhesion, the surface area was increased by creating a porous 3D Zn layer. A coverage of ∼70% of the surface with ACF1, achieved by electrophoretic deposition in an aqueous solution, preserved the desired Zn degradation as |Z| in the order of 103 Ω.cm2 is attained for both bare and coated samples in physiological conditions. The bioactivities of the ACF1 powder are a strong antibacterial activity against Escherichia coli (MIC of 1.95 µg/mL) and weaker against Staphylococcus aureus (MIC of 250 µg/mL), while osteoblasts' cytocompatibility is achieved for concentration ranging between 10 and 100 µg/mL. In its coating form, the degradation of Zn coated with ACF1 results in nalidixic acid release, which may convey antibacterial activity to the implant. The osteoinduction observe over this new biomaterial relates to the precipitation of an apatite layer built from the Ca(II) of ACF1. The work described herein, where unexplored eco-friendly approaches were used, presents a new trend for the design of multibioactive coatings on bioresorbable metallic materials.

Cytotoxicity in L929 fibroblasts and inhibition of herpes simplex virus type 1 Kupka by estuarine cyanobacteria extracts.

The cyanobacteria are known to be a rich source of metabolites with a variety of biological activities in different biological systems. In the present work, the bioactivity of aqueous and organic (methanolic and hexane) crude extracts of cyanobacteria isolated from estuarine ecosystems was studied using different bioassays. The assessment of DNA damage on the SOS gene repair region of mutant PQ37 strain of Escherichia coli was performed. Antiviral activity was evaluated against influenza virus, HRV-2, CVB3 and HSV-1 viruses using crystal violet dye uptake on HeLa, MDCK and GMK cell lines. Cytotoxicity evaluation was performed with L929 fibroblasts by MTT assay. Of a total of 18 cyanobacterial isolates studied, only the crude methanolic extract of LEGE 06078 proved to be genotoxic (IF > 1.5) in a dose-dependent manner and other four were putative candidates to induce DNA damage. Furthermore, the crude aqueous extract of LEGE 07085 showed anti- herpes type 1 activity (IC50 = 174.10 µg dry extract mL(-1)) while not presenting any cytotoxic activity against GMK cell lines. Of the 54 cyanobacterial extracts tested, only the crude methanolic and hexane ones showed impair on metabolic activity of L929 fibroblasts after long exposure (48-72 h). The inhibition of HSV-1 and the strong cytotoxicity against L929 cells observed emphasizes the importance of evaluating the impact of those estuarine cyanobacteria on aquatic ecosystem and on human health. The data also point out their potential application in HSV-1 treatment and pharmacological interest.

Long-term effects of parathyroid hormone, 1,25-dihydroxyvitamin d(3), and dexamethasone on the cell growth and functional activity of human osteogenic alveolar bone cell cultures.

The proliferation-differentiation behaviour of human alveolar bone cell cultures grown for 32 days in conditions that allowed the complete expression of the osteoblastic phenotype was significantly affected by the continuous presence of parathyroid hormone, 1, 25-dihydroxyvitamin D(3), or dexamethasone. Parathyroid hormone and, in particular, dexamethasone significantly induced the differentiation of osteoblastic cells. Moreover, cultures exposed to these hormones presented an earlier appearance and higher levels of alkaline phosphatase, and an increased ability to form calcium phosphate deposits in the extracellular matrix.