Two-stage exchange with antibiotic-loaded bone cement spacers remains the gold standard for chronic periprosthetic joint infection (PJI). Rifampicin is highly efficient on stationary-phase staphylococci in biofilm; however, its addition to PMMA to manufacture spacers prevents polymerization and reduces mechanical properties. Isolation of rifampicin during polymerization by microencapsulation could allow manufacturing rifampicin-loaded bone cement maintaining elution and mechanical properties. Microcapsules of rifampicin with alginate, polyhydroxybutyratehydroxyvalerate (PHBV), ethylcellulose and stearic acid (SA) were synthesized. Alginate and PHBV microcapsules were added to bone cement and elution, compression, bending, hardness, setting time and microbiological tests were performed. Repeated measures ANOVA and Bonferroni post-hoc test were performed, considering a p < 0.05 as statistical significance. Bone cement specimens containing alginate microcapsules eluted more rifampicin than PHBV microcapsules or non-encapsulated rifampicin over time (p < 0.012). Microencapsulation of rifampicin allowed PMMA to preserve mechanical properties in compression and bending tests. Cement with alginate microcapsules showed similar behavior in hardness tests to control cement over the study period (73 ± 1.68H ). PMMA with alginate microcapsules exhibited the largest zones of inhibition in microbiological tests. Statistically significant differences in mean diameters of zones of inhibition between PMMA loaded with alginate-rifampicin (p = 0.0001) and alginate-PHBV microcapsules (p = 0.0001) were detected. Rifampicin microencapsulation with alginate is the best choice to introduce rifampicin in PMMA preserving mechanical properties, setting time, elution, and antimicrobial properties. The main applicability of this study is the opportunity for obtaining rifampicin-loaded PMMA by microencapsulation of rifampicin in alginate microparticles, achieving high doses of rifampicin in infected tissues, increasing the successful of PJI treatment. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:459-466, 2018.

The aim of this study was to develop footwear materials and footwear packaging with scent properties using microencapsulated fragrances from essential oils. For that purpose, gelatine-carboxymethylcellulose (CMC) and melamine-formaldehyde (MF) resin-based microcapsules containing limonene were synthesised using complex coacervation and in situ polymerisation processes, respectively. The microcapsules were characterised using various experimental techniques and applied to footwear materials (leather and textile) as well as to paperboard as packaging material to evaluate their performance. The microcapsule durability under various conditions, such as rubbing and ironing, was analysed in order to simulate shoe manufacturing and shoe wearing conditions. The characterisation of the synthesised microcapsules showed two different delivery behaviours. On the one hand, MF microcapsules are more resistant so they may be incorporated into footwear materials that have to be exposed to high mechanical and thermal stresses, such as linings. On the other hand, gelatine-CMC microcapsules should be incorporated into footwear components, such as insoles, which are exposed to lower stresses because they are less resistant and might not resist the process conditions. The combination of both kinds of microcapsules could ensure a rapid as well as a long-lasting fragrance release.

No abstract

Functional materials with antimicrobial properties are being investigated in order to provide shoes with new properties and added value by incorporating natural antimicrobial agents to conventional materials (leather, fabrics, foams, etc). Microencapsulation is an effective method to protect these functional natural biocides from reactions with moisture, light, and oxygen. If a footwear material is treated with microencapsulated biocide agents, higher durability of functionality is expected. This article reports the evaluation of Melaleuca alternifolia (tea tree) oil which is a natural essential oil, as an antimicrobial agent for footwear application. Furthermore, microcapsules containing this essential oil were synthesized by in situ polymerization method using a melamine-formaldehyde resin as shell material in order to increase the durability of this natural biocide in footwear materials. Microcapsule characterization, such as particle size, morphology, and chemical properties was carried out for different oil to polymer ratios. Finally, the incorporation of the microencapsulated biocides into different footwear materials was also evaluated.

No abstract