Immobilization of recombinant lysostaphin on nanoparticle through biotin-streptavidin conjugation technology as a geometrical progressed confrontation against Staphylococcus aureus infection.

Antibiotic resistance and the colonization of resistant bacteria such as Staphylococcus aureus on surfaces, often in the form of biofilms, prolong hospitalization periods and increase mortality, thus is a significant concern for healthcare providers. To prevent biofilm formation, the inadequate concentration of using nanoparticles as antibacterial coating agents is one of the major obstacles. This study aimed to design a hypervalency TiO2 nanocomposite as a reserved base to carry a high amount of active antibacterial agents such as lysostaphin via a biotin-streptavidin-biotin bridge. The utilization of the streptavidin-biotin system could increase the abundance of lysostaphin. Lysostaphin was expressed in Escherichia coli and purified. Both recombinant lysostaphin and titanium oxide nanocomposite were conjugated with biotin and linked to a streptavidin bridge. The kinetics and activity of the enzyme were examined after each step utilizing N-acetylhexaglycine as a substrate. Physical characteristics of nanoparticles containing lysostaphin were determined using AFM, SEM, FTIR, and zeta potential. The results showed changes in size, charge, and morphology of the nanoparticles following the lysostaphin attachment. Also, the stability and kinetics of the active biological enzymes on nanoparticles were reexamined following 8 months of storage. Exploiting this approach, various biotinylated antibacterial agents could be prepared and rapidly immobilized on a nanoparticle as an active net against related infectious agents.

Immunoisolated transplantation of purified langerhans islet cells in testis cortex of male rats for treatment of streptozotocin induced diabetes mellitus.

The objective of this study is to induce experimental diabetes mellitus by streptozotocin in normal adult Wistar rats via comparison of changes in body weight, consumption of food, volume of water, urine and levels of glucose, insulin and C-peptide in serum, between normal and diabetic rats. Intra-venous injection of 60 mg/kg dose of streptozotocin in 250-300 g (75-90 days) adult Wistar rats makes pancreas swell and causes degeneration in Langerhans islet ß-cells and induces experimental diabetes mellitus in 2-4 days. For a microscopic study of degeneration of Langerhans islet ß-cells of diabetic rats, biopsy from pancreas tissue of diabetic and normal rats, staining and comparison between them, were done. In this process, after collagenase digestion of pancreas, islets were isolated, dissociated and identified by dithizone method and then with enzymatic procedure by DNase and trypsin, the islet cells changed into single cells and ß-cells were identified by immune fluorescence method and then assayed by flow-cytometer. Donor tissue in each step of work was prepared from 38 adult male Wistar rats weighted 250-300 g (75-90 days). Transplantation was performed in rats after 2-4 weeks of diabetes induction. In this study, the levels of insulin, C-peptide and glucose in diabetic rats reached to normal range as compared to un-diabetic rats in 20 days after transplantation of islet cells. Transplantation was performed under the cortex of testis as immunoisolated place for islet cells transplantation.

An investigation into the parameters affecting preparation of polybutyl cyanoacrylate nanoparticles by emulsion polymerization.

Emulsion polymerization was used to synthesize poly butyl cyanoacrylate nanoparticles in presence of steric stabilizer dextran 70. Nanoparticles were characterized by particle size analysis, scanning electron microscopy and light microscopy. Polymerization factors affecting particle size and distribution such as dextran 70, polysorbate 80 (PS 80) and H(+) concentration, polymerization time and temperature, and sonication were studied. Distinct concentrations of stabilizer were needed to produce proper nanoparticles. In this case, the appropriate value was 2 % of total volume. At pH 4 significant decrease in production efficiency demonstrated the substantial effect of H(+) concentration on nanoparticles. Furthermore significant increases in particle size and distribution was observed at 50 °C compared to room temperature. 0.001 % (v/v) PS 80 represented notable influence on size and distribution. In addition, shaped nanoparticles were obtained by altering polymerization time from 5.5 h to 18 h. Finally, nanoparticle features were influenced by different factors. Appropriate manipulating of such factors can lead to obtaining desirable nanoparticles.

Efficacy of pegylated liposomal etoposide nanoparticles on breast cancer cell lines.

BACKGROUND/AIM: This study aimed to investigate the efficacy of pegylated liposomal etoposide nanoparticles (NPs) against T-47D and MCF-7 breast cancer cell lines. MATERIALS AND METHODS: Pegylated liposomal etoposide NPs were prepared by reverse phase evaporation method. The size, size distribution, and zeta potential of the NPs was measured by a Zetasizer instrument. The cytotoxicity of NPs was inspected by methyl thiazol tetrazolium assay. The release pattern of the drug from the vesicles was studied by the dialysis method. Drug loading and encapsulation efficiency (EE) were also measured. RESULTS: The mean size, size distribution, and zeta potential of pegylated liposomal etoposide NPs were 491 ± 15.5 nm, 0.504 ± 0.14, and -35.8 ± 2.5 mV, respectively. Drug loading and EE were 10.3 ± 1.6% and 99.1 ± 2.8%, respectively. The etoposide release in the formulation was estimated at about 3.48% after 48 h. The cytotoxicity effect of etoposide NPs on T-47D and MCF-7 cell lines of breast cancer showed higher antitumor activity as compared with those of the free drug. CONCLUSION: Liposome-based NPs may hold great potential as a drug delivery system.