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Electrospun nanocomposite matrices based on poly(ε-caprolactone) (PCL), nano-hydroxyapatite (nHAp) and amoxicillin (AMX) were designed and investigated for dental applications. nHAp provides good biocompatibility, bioactivity, osteoconductivity, and osteoinductivity properties, and AMX, as antibiotic model, controls and/or reduces bacterial contamination of periodontal defects while enhancing tissue regeneration. A series of polymeric nanocomposites was obtained by varying both the antibiotic and nHAp contents. Fibrous membranes of different compositions were obtained by electrospinning technique, and morphological, thermal, mechanical and surface properties were characterized. The incorporation of AMX seemed to alter the nHAp distribution within the microfibrous matrix. The interaction between AMX and nHAp affected the mechanical performance and modulated the antibiotic release behavior. AMX release profiles presented a burst release that depended on nHAp content, followed by a slow release stage where the drug content (85-100%) was released in 3 weeks. The antimicrobial activity of the AMX-loaded membranes was tested with four bacterial strains depended on both the drug and nHAp contents. Extensive mineralization in simulated body fluid (SBF) was evidenced by SEM/EDX analysis after 21 days. The studied electrospun nanocomposite amoxicillin-loaded membranes could be a promising fibrous-based antibiotic carrier system for dental and tissue engineering applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 966-976, 2017.

The goal of this study was to analyze the response of osteoblasts cultured on strontium substituted hydroxyapatites (HAP-Sr) of well-defined high crystallinity deposited as thin films on glass plates. Up to now, this aspect has not been carefully investigated in the context of bio-ceramics. In this study, we present the osteoblasts activity on synthesized HAP-Sr for different amounts of strontium substitution for calcium within the hydroxyapatite (Ca10(PO4)6(OH)2, HAP) lattice, namely HAP-5%Sr, HAP-10%Sr, HAP-15%Sr and HAP-59.2%Sr (Sr-HAP, of formula Sr10(PO4)6(OH)2), in comparison with stoichiometric pure HAP, chosen as control. Each bio-ceramic was deposited as thin multilayers self-assembled substrate (scaffold) and chemically bonded to the surface of glass plates. These coatings revealed by AFM and SEM imaging a granular texture formed from bio-ceramic nanoparticles. They possessed a high degree of crystallinity, i.e. 68% to 86%, depending on the Sr amount within the HAP lattice, as judged by XRD. Osteoblasts were cultured up to 21days and displayed enhanced adhesion and proliferation particularly evidenced on relatively high strontium contents (especially 5 and 10 weight %, determined by SEM-EDX), where the alkaline phosphatase activity and type I collagen were strongly evidenced. These bio-ceramics showed a high in vitro biocompatibility stimulating the activity of osteoblasts in the process of bone formation. These nano biomaterials can have applications in orthopedic and dental surgery improving the osteointegration as coatings of bone implants as well as for bone repair and regeneration.

There is a continuous need for discovering new nanomaterials with antibacterial activity against various pathogens, like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). This study was performed to assess the antimicrobial activity of two novel nanostructured forsterites, both in the absence and the presence of silver nanoparticles (AgNPs). The two nano forsterites (FS) were prepared by advanced sol-gel (FSsg) and precipitation (FSpp) methods. Preparation of colloidal AgNPs systems was realized by using the precursor, AgNO3, and the trisodium citrate and tanic acid assuring the formation and stabilization of AgNPs. The characterization of nano forsterite powders was carried out using complementary physical methods: XRD, SEM, and AFM. The AgNPs were characterized by UV-Vis spectra, STEM and AFM imaging. The antimicrobial activity was studied by the agar well diffusion method both in the FS native state, as FSsg and FSpp, and in their mixture with silver nanoparticles (AgNPs). The inhibitory effect of synthesized forsterites, FSsg and FSpp, particularly variants with AgNPs was found only on the S. aureus strain, the zones of inhibition being between 8 and 10 mm, and more intensely expressed in the FSpp-AgNPs dispersions. These findings open new orthopedic applications of these systems, particularly for antimicrobial coated metallic implants.

The wet chemical synthesis of silver nanoparticles (AgNPs) by reduction of silver nitrate with sodium citrate, tannic acid, and their mixture is reported. The obtained silver nanoparticles were investigated by UV-Vis spectroscopy, scanning transmission electron microscopy (STEM), and atomic force microscopy (AFM) images and their antibacterial effect against Escherichia coli was assessed.

Recent studies suggest that Candida albicans colonization is associated with several gastrointestinal inflammatory disorders and is also responsible for the delay in ulcer healing. No data are reported about the effects of C. albicans on the nonsteroidal anti-inflammatory drugs (NSAIDs)-induced necroinflammatory lesions. On the other hand, beneficial effects of NSAIDs regarding the colonization potential with C. albicans have been reported. Our aim was to investigate whether the association between NSAIDs and C. albicans could potentially induce necroinflammatory lesions in the guinea pigs gastric and enteral mucosa. Three interventional groups of 11 guinea pigs each were investigated after 5 days of receiving indomethacin, C. albicans or the association of both. C. albicans and necroinflammatory lesions were graded based on histological examinations. Statistical analysis used Mann-Whitney nonparametric test. NSAIDs did not significantly decrease C. albicans colonization grades on gastrointestinal mucosa. Administration of indomethacin subsequent to C. albicans determined significantly more severe necroinflammatory lesions compared to group that only received C. albicans. The association of NSAIDs and C. albicans did not cause significantly more severe degenerative or inflammatory lesions compared to the administration of only NSAIDs in this experimental model. Associations between NSAIDs and C. albicans caused significantly more severe necroinflammatory injuries than the lesions produced by C. albicans, without enhancing the mucosal injury or inflammation caused by NSAIDs.

Iodine based products have been and are still used in medicine as disinfectant or antiseptic substances, because of their bactericidal, sporicidal, protocidal and disinfection effect. Algaecide effect has been less studied and represents a strong motivation for this study. This paper is aiming to test the sensitivity to iodine based products of unicellular algae of the genus Prototheca. Such products might be used for the treatment of diseases involving these pathogens. A total number of twenty-two Prototheca zopfii strains isolated from cows with mastitis or bovine shelters, were tested within this study. The algal strains were identified based on morphological characteristics (shape, size, presence of endospores), cultural (liquid and solid media characteristics) and biochemical (fermentation of sugars). Prototheca wickerhamii ATCC 16529 reference strain was also included in the evaluation. Iodinated products used were represented by: Lugol solution, iodine tincture, betadine, videne and potassium iodide. Determination of the inhibitory effect was measured by diffusion technique in agarose gel and by liquid medium dilution method. For the tincture of iodine and betadine, the inhibitory effect was also appreciated in relation with the time of contact (5, 10, 15, 30 and 60 minutes). By the agar diffusion technique, it was found that inhibition zones varying sizes were correlated with the composition of those products. For the 22 Prototheca zopfii tested strains, the size of inhibition areas was within the following values (average diameter): iodine tincture 25.71 mm, betadine 26.4 mm, videne 25.61 mm, Lugol's solution 11.33 mm and potassium iodide 11.14 mm. For Prototheca wickerhamii strain inhibition areas had the following values: betadine 26 mm, iodine tincture 24 mm, videne 24 mm, Lugol's solution 10 mm, potassium iodine 14 mm. In case of different contact times meant to establish the algaecide effect-occurred in the first 5 minutes of contact, for both iodine tincture and betadine. Iodine based products tested showed inhibitory effect on algal strains. The best efficacy was found for betadine and iodine tincture (pharmaceutical/commercial products). The inhibitory effect occurs in the first 5 minutes of contact. There was no resistance phenomenon nor the presence of resistant colonies in the inhibition zones.

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