Electrospun Membrane Surface Modification by Sonocoating with HA and ZnO:Ag Nanoparticles-Characterization and Evaluation of Osteoblasts and Bacterial Cell Behavior In Vitro.

Guided tissue regeneration and guided bone regeneration membranes are some of the most common products used for bone regeneration in periodontal dentistry. The main disadvantage of commercially available membranes is their lack of bone cell stimulation and easy bacterial colonization. The aim of this work was to design and fabricate a new membrane construct composed of electrospun poly (D,L-lactic acid)/poly (lactic-co-glycolic acid) fibers sonocoated with layers of nanoparticles with specific properties, i.e., hydroxyapatite and bimetallic nanocomposite of zinc oxide-silver. Thus, within this study, four different variants of biomaterials were evaluated, namely: poly (D,L-lactic acid)/poly (lactic-co-glycolic acid) biomaterial, poly(D,L-lactic acid)/poly (lactic-co-glycolic acid)/nano hydroxyapatite biomaterial, poly (D,L-lactic acid)/poly (lactic-co-glycolic acid)/nano zinc oxide-silver biomaterial, and poly (D,L-lactic acid)/poly (lactic-co-glycolic acid)/nano hydroxyapatite/nano zinc oxide-silver biomaterial. First, it was demonstrated that the wettability of biomaterials-a prerequisite property important for ensuring desired biological response-was highly increased after the sonocoating process. Moreover, it was indicated that biomaterials composed of poly (D,L-lactic acid)/poly (lactic-co-glycolic acid) with or without a nano hydroxyapatite layer allowed proper osteoblast growth and proliferation, but did not have antibacterial properties. Addition of a nano zinc oxide-silver layer to the biomaterial inhibited growth of bacterial cells around the membrane, but at the same time induced very high cytotoxicity towards osteoblasts. Most importantly, enrichment of this biomaterial with a supplementary underlayer of nano hydroxyapatite allowed for the preservation of antibacterial properties and also a decrease in the cytotoxicity towards bone cells, associated with the presence of a nano zinc oxide-silver layer. Thus, the final structure of the composite poly (D,L-lactic acid)/poly (lactic-co-glycolic acid)/nano hydroxyapatite/nano zinc oxide-silver seems to be a promising construct for tissue engineering products, especially guided tissue regeneration/guided bone regeneration membranes. Nevertheless, additional research is needed in order to improve the developed construct, which will simultaneously protect the biomaterial from bacterial colonization and enhance the bone regeneration properties.

Dendrimer based theranostic nanostructures for combined chemo- and photothermal therapy of liver cancer cells in vitro.

Here we report the synthesis of multifunctional nanocarriers based on PAMAM dendrimers generation (G) 4.0, 5.0 and 6.0 fixed to polydopamine (PDA) coated magnetite nanoparticles (Fe3O4). Synthesized nanoplatforms were characterized by transmission electron microscopy (TEM), the electrokinetic (zeta) potential, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and magnetic resonance imaging (MRI). Further, we show as a proof of concept that nanocarriers functionalized with G 5.0 could be successfully applied in combined chemo- and photothermal therapy (CT-PTT) of the liver cancer cells. The cooperative effect of the modalities mentioned above led to higher mortality of cancer cells when compared to their individual performance. Moreover, the performed in vitro studies revealed that the application of dual therapy triggered the desired cell death mechanism-apoptosis. Furthermore, performed tests using Magnetic Resonance Imaging (MRI) showed that our materials have competitive contrast properties. Overall, the functionality of dendrimers has been extended by merging them with magnetic nanoparticles resulting in multifunctional hybrid nanostructures that are promising smart drug delivery system for cancer therapy.

[Evaluation of biocidal properties of silver nanoparticles against cariogenic bacteria]. / Ocena bakteriobójczej aktywnosci koloidalnego roztworu nanoczastek srebra w stosunku do bakterii próchnicotwórczych.

INTRODUCTION: Antimicrobial properties of silver nanoparticles (SNP's) have been recentl well evaluated, and now are being considered as excellent candidates for therapeutic purposes. It is confirmed, that various solutions of colloidal SNP's possess significant antibacterial properties against such species as: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa even at low concentrations, although there have been so far only a few researches evaluating antimicrobial activity of SNP's against cariogenic bacteria: Streptococcus mutans, Streptococcus salivarius and Streptococcus mitis responsible for initiation of dental carries. Tooth decay is infectious disease an worldwide, which may occur in patients of every age. Nanotechnology creates a new approach of designing of medical devices preventing or reducing bacterial colonization. METHODS: Colloidal silver solution (CSS) of concentration 350 ppm was used in this research. Nanoparticles size, shape and solution stability were evaluated. 16 strains of cariogenic bacteria, 4 isolates of each species: S. mutans, S. salivarius, S. sanguinis and S, mitis were obtained from plaque swabs of 7 patients treated for dental carries at Department of Conservative Dentistry, Medical University of Warsaw. MIC and MBC values for CSS's were evaluated. RESULTS: CSS used in this research is of good stability. No agglomeration or coalescence was observed during 24 hours of experiment. Silver nanoparticles were of round shape and had mean size of 67 nm. MIC values were: 12-25 ppm for S. salivarius, 25 ppm for S. sanguinis, 50-100 ppm for S. mitis and 50 ppm for S. mutans, while MBC values after 1 hour of bacterial contact with nanoparticles were 200-350 ppm for all cariogenic bacterial species. After 24 hours of contact MBC values were: 25-50 ppm for S. salivarius and S. sanguinis, 100-200 ppm for S. mitis and 200 ppmfor S. mutans. CONCLUSIONS: Antimicrobial properties of CSS depend on nanoparticles concentration and interaction time with bacteria. The susceptibility of cariogenic oral streptococci to silver nanoparticles is diversified. Sufficient concentration which inhibited all cariogenic bacteria in our research was 200 ppm after long (24 hours) period of silver nanoparticles interaction with bacteria.