In situ synthesis of silver or selenium nanoparticles on cationized cellulose fabrics for antimicrobial application.

In this study, we developed a method to prepare inorganic nanoparticles in situ on the surface of cationized cellulose using a rapid microwave-assisted synthesis. Selenium nanoparticles (SeNPs) were employed as a novel type of antimicrobial agent and, using the same method, silver nanoparticles (AgNPs) were also prepared. The results demonstrated that both SeNPs and AgNPs of about 100 nm in size were generated on the cationized cellulose fabrics. The antibacterial tests revealed that the presence of SeNPs clearly improved the antibacterial performance of cationized cellulose in a similar way as AgNPs. The functionalised fabrics demonstrated strong antibacterial activity when assessed using the challenge test method, even after repeated washing. Microscopic investigations revealed that the bacterial cells were visually damaged through contact with the functionalised fabrics. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a new approach to prepare cationic cellulose fabrics functionalised with Se or Ag nanoparticles, which exhibit excellent antimicrobial performance, low cytotoxicity and good laundry durability. We have demonstrated that SeNPs can be a good alternative to AgNPs and the functionalised fabrics have great potential to serve as an anti-infective material.

Master of Pharmacy students' knowledge and awareness of antibiotic use, resistance and stewardship.

INTRODUCTION: Antibiotic resistance has become a global public health concern. In this study, we investigated the knowledge and awareness of antibiotic use, resistance and stewardship, held by the pharmacy students currently studying at the University of Brighton. METHODS: This was a cross-sectional, online survey, and email invitations to participate were sent to all students attending our Master of Pharmacy (MPharm) course (n=583). Students' knowledge was assessed with 29 items; responses for these were totaled before comparison among students. Comparison of scores between groups of students was performed using the Kruskal-Wallis or the Mann-Whitney U test, as appropriate. RESULTS: The response rate was 32%. The overall median knowledge score was 7.9. There was a statistically significant difference in knowledge scores between years of study (p=0.02), particularly between year of study 1 (7.6) and 4 (8.3). A statistically significant difference was found between the knowledge scores of male (8.4) and female (7.9) students (p=0.03). Most students believed a strong knowledge of antibiotics, and microbiology and infection control is important for their pharmacy careers and more than 90% agreed that antibiotic resistance will be a greater clinical problem in the future. DISCUSSION AND CONCLUSIONS: Although the MPharm students studied achieved good overall knowledge scores, a significant proportion showed a lack of understanding with regards to some important aspects of antibiotic resistance mechanisms, factors promoting the emergence and spread of antibiotic resistance, and antibiotic stewardship policies.

Chitosan microparticles for the controlled delivery of fluoride.

OBJECTIVES: To manufacture and characterise chitosan/fluoride microparticles prepared by spray drying and assess their utility as controlled release vehicles for fluoride. METHODS: Microparticles were manufactured from dispersions containing 1.0% and 2.0% (w/v) chitosan and 0.20% or 0.40% (w/v) NaF in the absence/presence of glutaraldehyde. Particle size distributions were determined using laser diffraction; fluoride loading and release were determined by ion-selective electrode. Release profiles were studied in isotonic media (pH 5.5) over 360 min; microparticles exhibiting greatest cumulative fluoride release were further evaluated at pH 4.0 and 7.0. Particle morphology was investigated using environmental scanning electron microscopy. Bioadhesion parameters were determined with a texture-probe analyser. RESULTS: Microparticles exhibited low polydispersity and volume mean diameters (VMDs) <6 µm. VMDs increased on doubling the chitosan/fluoride concentrations but were largely independent of glutaraldehyde concentration. Recovered yields were inversely proportional to dispersion viscosity due to compromised fluid atomisation; adding NaF reduced viscosity and improved yields. Best-case entrapment efficiency and NaF loading were 84.1% and 14%, respectively. Release profiles were biphasic, releasing 40-60% of the total fluoride during the first 600 s, followed by a prolonged release phase extending out to 6h. Incorporation of 0.40% NaF to the 2.0% chitosan dispersion yielded microparticles with reduced bioadhesive parameters (F(max) and WOA) versus the chitosan-only control whilst retaining significant bioadhesive potential. CONCLUSIONS: Bioadhesive chitosan/fluoride microparticles manufactured using a spray-drying protocol have been extensively characterised and further opportunity for optimisation identified. These microparticles may provide a means of increasing fluoride uptake from oral care products to provide increased protection against caries, however further work is required to demonstrate this principle in vivo. CLINICAL SIGNIFICANCE: Spray-drying is a low-cost route for the manufacture of bioadhesive chitosan/fluoride microparticles which can be exploited as controlled fluoride release agents to aid fluoride retention in the oral cavity. The potential exists to optimise release profiles to suit the delivery format thereby maximising the cariostatic benefits.