Polyelectrolyte-coated liposomes microfluidically assembled in one-step for enhancing cell endocytosis and in-vivo immune responses.

To enhance the cellular uptake of liposomes, we prepared conventional liposomes with targeting molecules and surface-charged liposomes and evaluated their potential as nano-carriers and vaccine adjuvants by comparing their endocytosis efficiencies using immune cells. Surface-charged liposomes were synthesized via a one-step microfluidic method, which provided a novel, simple, fast, and highly reproducible method for preparing liposomes. Flow cytometry revealed that cationic polyelectrolyte-coated liposomes exhibited higher endocytosis efficiencies (of up to a factor of 100) in A774A.1 cells and JAWs II cells compared with uncoated liposomes or those coated with anionic polyelectrolytes. Positively charged liposomes exhibited some cytotoxicity at quaternary-chitosan coating concentrations higher than 6 mg/mL; however, significantly lower cytotoxicities (by a factor of almost ten) were obtained by protein mixing. Furthermore, BALB/c mice vaccinated with a mixture of Anthrax vaccine adsorbed (AVA) and quaternary chitosan-coated liposomes showed faster and stronger anti-PA IgG inductions compared to those vaccinated with AVA alone, with titers positively correlating with the amount of cationic liposome used. This finding clearly reveals that quaternary chitosan-coated liposomes act as both nano-carriers and vaccine adjuvants that significantly enhance in-vivo immune responses to vaccines with low immunogenicities.

The effect of dentin surface treatment with disinfectant on the shear bonding strength of luting cements.

Background/purpose: Few studies have comprehensively assessed the shear bonding strength of the luting cements between abutments and fixed partial dentures after dentin surface treatment with disinfectants. The purpose of the study was to evaluate the effect of three commonly used disinfectants (2.5% sodium hypochlorite, 0.2% chlorhexidine, and 0.2% benzalkonium chloride) on the shear bonding strength of four luting cements. Materials and methods: Teeth were mounted on Teflon cylinders and prepared for dentin exposure. Three different disinfectants were used to treat the dentin surface. Nickel-chromium posts were cemented with resin cement, glass ionomer cement, polycarboxylate cement, or zinc phosphate cement. The shear bonding strength of the cement was examined using an Instron testing machine. Two-way analysis of variance (ANOVA) was used to examine the differences in shear bonding strength between the cements. If a statistically significant difference was found through ANOVA, a post hoc test with Tukey's honest significant difference was conducted. Results: Disinfectants significantly decreased the shear bonding strength of resin cement, with 2.5% sodium hypochlorite causing the most substantial decrease. The zinc phosphate cement group displayed minimal shear bonding strength regardless of the disinfectant used. Conclusion: The presence of 2.5% sodium hypochlorite significantly reduced the shear bonding strength of resin cements. During permanent cementation of indirect restorations, the choice of luting cement paired with the proper disinfectant is of utmost importance to maintain the shear bonding strength.

Alginate-Capped Silver Nanoparticles as a Potent Anti-mycobacterial Agent Against Mycobacterium tuberculosis.

Tuberculosis (TB) is a leading cause of death from a single infectious agent, Mycobacterium tuberculosis (Mtb). Although progress has been made in TB control, still about 10 million people worldwide develop TB annually and 1.5 million die of the disease. The rapid emergence of aggressive, drug-resistant strains and latent infections have caused TB to remain a global health challenge. TB treatments are lengthy and their side effects lead to poor patient compliance, which in turn has contributed to the drug resistance and exacerbated the TB epidemic. The relatively low output of newly approved antibiotics has spurred research interest toward alternative antibacterial molecules such as silver nanoparticles (AgNPs). In the present study, we use the natural biopolymer alginate to serve as a stabilizer and/or reductant to green synthesize AgNPs, which improves their biocompatibility and avoids the use of toxic chemicals. The average size of the alginate-capped AgNPs (ALG-AgNPs) was characterized as nanoscale, and the particles were round in shape. Drug susceptibility tests showed that these ALG-AgNPs are effective against both drug-resistant Mtb strains and dormant Mtb. A bacterial cell-wall permeability assay showed that the anti-mycobacterial action of ALG-AgNPs is mediated through an increase in cell-wall permeability. Notably, the anti-mycobacterial potential of ALG-AgNPs was effective in both zebrafish and mouse TB animal models in vivo. These results suggest that ALG-AgNPs could provide a new therapeutic option to overcome the difficulties of current TB treatments.

Comparison of the internal fit of metal crowns fabricated by traditional casting, computer numerical control milling, and three-dimensional printing.

This experimental study aimed to compare the internal fit (marginal fit and internal discrepancy) of metal crowns fabricated by traditional casting and digital methods (computer numerically controlled (CNC) milling and three-dimensional [3D] printing). Thirty standard master abutment models were fabricated using a 3D printing technique with digital software. Metal crowns were fabricated by traditional casting, CNC milling, and 3D printing. The silicon replica method was used to measure the marginal and internal fit. A thin layer of low-viscosity polyvinyl siloxane material was placed inside each crown and on the die (like a seat) until the material was set. Replicas were examined at four reference points under a microscope: the central pit (M1), cusp tip (M2), axial wall (M3), and margin (M4). The measured data were analyzed using a one-way analysis of variance (ANOVA) to verify statistical significance, which was set at p < 0.05. In the traditional casting group, the minimum distance measured was at M3 (90.68 ± 14.4 µm) and the maximum distance measured was at M1 (145.12 ± 22 µm). In the milling group, the minimum distance measured was at M3 (71.85 ± 23.69 µm) and the maximum distance measured was at M1 (108.68 ± 10.52 µm). In the 3D printing group, the minimum distance measured was at M3 (100.59 ± 9.26 µm) and the maximum distance measured was at M1 (122.33 ± 7.66 µm). The mean discrepancy for the traditional casting, CNC milling, and 3D printing groups was 120.20, 92.15, and 111.85 µm, respectively, showing significant differences (P < 0.05). All three methods of metal crown fabrication, that is, traditional casting, CNC milling, and 3D printing, had values within the clinically acceptable range. The marginal and internal fit of the crown was far superior in the CNC milling method.

Rapid typing of carbapenem-resistant Acinetobacter baumannii and Acinetobacter nosocomialis by multiplex Pan- and OXA-PCR assays.

Introduction. Outbreaks of carbapenem-resistant A. baumannii and A. nosocomialis have occurred worldwide in healthcare settings. Rapid and reliable molecular typing of bacterial isolates is vital for the effective surveillance of institutional outbreaks. The Pan-PCR and OXA-PCR assays are two multiplex PCR-based assays for the molecular typing of Acinetobacter species.Gap statement. However, few studies have investigated the discriminatory power of two multiplex PCR assays in in the genotyping of Acinetobacter species.Aim. We aimed to evaluate the efficacies of the Pan-PCR and OXA-PCR assays for molecular typing of A. baumannii and A. nosocomialis.Methodology. A total of 105 carbapenem-resistant A. baumannii isolates (CRABs) and 93 carbapenem-resistant A. nosocomialis isolates (CRANs) obtained from blood cultures were used for molecular typing by the Pan-PCR and OXA-PCR assays and two multilocus sequence typing (MLST) schemes.Results. The isolates were individually divided into 12 and 21 different sequence types via the Pasteur and Oxford MLST schemes, respectively. Additionally, these isolates were distinguished into 18 different types by the Pan-PCR and OXA-PCR assays. The results of the Pan-PCR and OXA-PCR assays distinguished CRABs and CRANs with a sensitivity of 98.13 % and a specificity of 100 %.Conclusion. The Pan-PCR and OXA-PCR assays are promising alternative methods for rapid molecular typing of CRABs and CRANs in a routine laboratory setting.

Antifungal effect of tissue conditioners containing poly(acryloyloxyethyltrimethyl ammonium chloride)-grafted chitosan on Candida albicans growth in vitro.

BACKGROUND/PURPOSE: Denture stomatitis is a pathological condition affecting the mucosa underneath ill-fitting dentures, and Candida albicans is considered its main etiologic factor. Tissue conditioners are temporary lining materials often applied to dentures to treat inflamed tissues. However, tissue conditioners do not exert antifungal activity, and the soft surface texture harbors C. albicans easily. The aim of this study was to examine the antifungal activity of tissue conditioners modified with chitosan (CS) or a quaternized chitosan (QCS), which was synthesized by grafting 2-[(acryloyloxy)ethyl] trimethyl ammonium chloride onto CS. MATERIALS AND METHODS: Tissue conditioners containing varying weight percentages of CS or QCS were prepared as experimental discs 10 mm in diameter and 1 mm in thickness. Samples were co-cultured with C. albicans and the number of colony forming units was recorded. Other evaluations included cell toxicity and tensile bond strength to the resin denture base. RESULTS: It was found significantly fewer fungal colonies in tissue conditioners modified with CS or QCS, and none when the weight percentage of QCS exceeded 5%. CS and QCS did not affect the viability of human gingival epithelium cells or fibroblasts, and tensile bond strength did not differ between control and modified tissue conditioners. CONCLUSION: This study provides a foundation for the development of QCS as a novel and safe antifungal agent applied to tissue conditioners in clinical practice.

Silk-sericin degummed wastewater solution-derived and nitrogen enriched porous carbon nanosheets for robust biological imaging of stem cells.

Appreciated raw materials like silk-sericin can be recovered from silk-textile industrial waste for the production of novel functional nanomaterials. In this study, highly fluorescent sericin based carbon nanosheets (SCN) were produced from industrial wastewater containing silk-sericin as a precursor, and was applied as bio-imaging application for oral fat stem cells. A simple one-pot, hydrothermal carbonization method was used to produce SCN at a 180°C. The obtained hydrothermal carbons exhibited strong fluorescence properties due to the presence of strong polar groups, such as carboxyl, amino and amide groups in the surface. Heteroatom functionalization of the SCN leads to the property of fluorescence due to enriched nitrogen and was confirmed by X-ray photoelectron and Fourier transform infrared spectroscopy. The plate-like morphology of SCN about 35nm in size was evaluated by transmission electron microscopy. The carbon 13 nuclear magnetic resonance results revealed that nano-sized fluorescent SCN formed during carbonization and functionalization occurred through dehydration of the sericin protein. Moreover, the prepared SCNs demonstrated low toxicity and their suitability for bio-imaging applications was demonstrated to the oral fat stem cells. Overall, sericin degumming wastewater from the silk textile industry can be utilized for the production of SCNs for stem cells bio-imaging applications.

Association between History of Dental Amalgam Fillings and Risk of Parkinson's Disease: A Population-Based Retrospective Cohort Study in Taiwan.

The impact of dental amalgam on the development of Parkinson's disease (PD) is still uncertain, although a positive association between dental amalgam and PD has been found in a few case-control studies. The patients with amalgam fillings restored between 2000 and 2008 were identified by using the National Health Insurance Research Database (NHIRD) in Taiwan. The same number of patients who had no new amalgam filling restored was matched by sex, age, and treatment date. Both cohorts were followed up from the treatment date until the date of diagnosis of PD, death, or the end of the year 2008. The individuals who received amalgam fillings had a significantly higher risk of PD afterward (adjusted hazard ratio [HR]=1.583, 95% confidence interval [CI]=1.122-2.234, p=0.0089) than those who did not. In the individuals who received amalgam fillings, being diagnosed with diabetes or hyperlipidemia demonstrated a significantly lower HR of PD occurrence than in the patients without diabetes or hyperlipidemia (HR=0.449, 95% CI=0.254-0.794, p=0.0059; HR=0.445, 95% CI=0.260-0.763, p=0.0032) after adjusting for comorbidities and Charlson-Deyo Comorbidity Index (CCI) scores. Meanwhile, hypertension increased the hazard risk of PD (HR=1.645, 95% CI=1.098-2.464, p=0.0159). The patients exposed to dental amalgam fillings were 1.583 times more likely to have PD afterward compared to their non-exposed counterparts after adjusting for comorbidities and CCI scores.