Biodegradable 3D-printable inks based on pectin have been developed as a system for direct and indirect wound-dressing applications, suitable for 3D printing technologies. The 3D-printable inks formed free-standing transparent films upon drying, with the latter exhibiting fast disintegration upon contact with aqueous media. The antimicrobial and wound-healing activities of the inks have been successfully enhanced by the addition of particles, comprised of chitosan and cyclodextrin inclusion complexes with propolis extract. Response Surface Methodology (RSM) was applied for the optimization of the inks (extrusion-printing pressure, shrinkage minimization over-drying, increased water uptake and minimization of the disintegration of the dry patches upon contact with aqueous media). Particles comprised of chitosan and cyclodextrin/propolis extract inclusion complexes (CCP), bearing antimicrobial properties, were optimized and integrated with the produced inks. The bioprinted patches were assessed for their cytocompatibility, antimicrobial activity and in vitro wound-healing properties. These studies were complemented with ex vivo skin adhesion measurements, a relative surface hydrophobicity and opacity measurement, mechanical properties, visualization, and spectroscopic techniques. The in vitro wound-healing studies revealed that the 3D-bioprinted patches enhanced the in vitro wound-healing process, while the incorporation of CCP further enhanced wound-healing, as well as the antimicrobial activity of the patches.

https://www.mdpi.com/1999-4923/12/1/56/pdf

Development of Bio-Active Patches Based on Pectin for the Treatment of Ulcers and Wounds Using 3D-Bioprinting Technology

Effective strategies of sustained release and retention enhancement of essential oils in active food packaging films/coatings

Antimicrobial potential of spray drying encapsulated thyme (Thymus vulgaris) essential oil on the conservation of hamburger-like meat products.

Preparation and characterization of gellan gum-chitosan polyelectrolyte complex films with the incorporation of thyme essential oil nanoemulsion

chilled meat is extremely susceptible to microbial contamination during processing and storage. Therefore, a new edible starch-based antibacterial composite film with thyme oil microemulsions(ME) or microcapsules(TMS) was prepared. The slow-release characteristic, bacteriostatic property and the preservation effect on chilled meat of the films were evaluated. The results showed that the cumulative release rates of composite films containing 5% microemulsion and 5% microcapsule were much less than the film containing 5% thyme oil. The antibacterial effect of film containing thyme oil microemulsion (ME-S) was stronger than that of film containing thyme oil microcapsule (TMS-S), but both of their antibacterial effect increased as the concentration increased. The overall fresh-keeping effect of composite films on chilled meat at 0–4 was blank

Effect of potato starch-based antibacterial composite films with thyme oil microemulsion or microcapsule on shelf life of chilled meat

Thyme essential oil-loaded microcapsules (TMS) were fabricated using natural polysaccharide chitosan (CS) and sodium alginate (SA) as the shell material via the method of layer-by-layer (LBL) assembly. The accumulated release rates of thyme oil and microcapsules at 4 °C were 42.50% and 10.16%, respectively. After heating at 100 °C for 5 hr, the release rate of the 0, 2, 4, 6 layers assembled microcapsules were 100%, 48.84%, 28.38%, 19.3%, severally. Microcapsules also had good pH sensitivity in the range of 4 to 10. Antimicrobial function studies showed that the microcapsules are more effective than thyme oil for three tested microorganisms. When the temperature rose from 37 °C to 121 °C, the antibacterial zone of thyme oil gradually decreased from 18.5 ± 0.6 mm to 12.3 ± 0.6 mm, although inhibition rate of microcapsules increased from 87.97% to 99.75%. The antibacterial effect of thyme oil declined with the increase of pH, in terms of microcapsules, the efficiency was better under acidic or alkaline conditions. The thyme oil microcapsules can suppress the growth of Staphylococcus aureus in milk and prolong its shelf life. It was determined that this microcapsule could be a potential alternative as a natural antimicrobial agent in food and pharmaceutical industries. PRACTICAL APPLICATION: This work provided release performance and mechanism of layer-by-layer (LBL) thyme oil microcapsule under different conditions, and further studies showed its antibacterial ability to explore how herb essential oils can be potentially applied in food packaging and antibacterial areas.; © 2019 Institute of Food Technologists®.

Controlled Release Mechanism and Antibacterial Effect of Layer-By-Layer Self-Assembly Thyme Oil Microcapsule.

The aim of this study was to produce and characterize microcapsules of thyme oil and finally appraise the extent of stability improvement. The optimum process conditions obtained from orthogonal tests were as follows: ratio of core material to wall 0.5, temperature 40 °C, pH value 3.0 and time 20 min, where the practical encapsulation efficiency was 85.17±1.35%. The microcapsules belong to the nanometric range as the average particle diameter was 531.17±77.12 nm. The results from structural analysis indicated that no significant chemical bond occurred during the encapsulation process and the microcapsules remained stable when the encapsulation was conducted at a temperature below 53.1 °C. Especially, the retention rate of thyme oil in microcapsules remained 39.21% at 4 °C, 36.99% at 25 °C and 33.80% at 40 °C after 30 d of storage. Moreover, protection from light exposure presented a positive impact on the storage stability of thyme oil microcapsules.

Wu Feng

Papers

Effect of potato starch-based antibacterial composite films with thyme oil microemulsion or microcapsule on shelf life of chilled meat

Controlled Release Mechanism and Antibacterial Effect of Layer-By-Layer Self-Assembly Thyme Oil Microcapsule.

Physical Properties and Stabilization of Microcapsules Containing Thyme Oil by Complex Coacervation

Transcriptome and protein networks to elucidate the mechanism underlying nitrite degradation by Lactiplantibacillus plantarum.