Microemulsification of essential oils for the development of antimicrobial and mosquito repellent functional coatings for textiles.

AIMS: To develop an essential oil (EO)-loaded textile coating using an environmentally friendly microemulsion technique to achieve both antimicrobial and mosquito repellent functionalities. METHODS AND RESULTS: Minimum inhibitory concentrations and fractional inhibitory concentrations of litsea, lemon and rosemary EOs were determined against Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa and Trichophyton rubrum. A 1 : 2 mixture of litsea and lemon EOs inhibited all the microorganisms tested and was incorporated into a chitosan-sodium alginate assembly by a microemulsification process. The EO-loaded microemulsions were applied to cotton and polyester fabrics using a soak-pad-dry method. The textile challenge tests demonstrated 7-8 log10 reductions of S. epidermidis, S. aureus and E. coli after 24 h and T. rubrum after 48 h. Aedes aegypti mosquito repellency was also assessed which demonstrated 71·43% repellency compared to 52·94% by neat EO-impregnated cotton. CONCLUSIONS: Textiles treated with the litsea and lemon EO microemulsion showed strong antimicrobial activity against the skin associated microorganisms E. coli, S. aureus, S. epidermidis and T. rubrum and potential mosquito repellent properties. SIGNIFICANCE AND IMPACT OF THE STUDY: EOs could be useful for the development of natural, environmentally friendly functional textiles to protect textiles and users from microbial contamination in addition to possessing other beneficial properties such as mosquito repellency.

Engineering optimisation of commercial facemask formulations capable of improving skin moisturisation.

INTRODUCTION: The stratum corneum is the biggest obstacle in cosmetics with respect to skin moisturisation. Many approaches have been taken to overcome the barrier, one of which is incorporating natural cosmeceuticals into cosmetic products to enhance moisturisation effects. Here, a commercial facemask formulation was electrospun to develop dry facemasks capable of hosting cosmeceuticals within the pores of incorporated mesoporous silica. METHODS: Ethanolic solutions containing 40% w/w of the marketed facemask (7th Heaven Dead Sea peel-off facemask) and mesoporous silica were prepared and electrically processed at 30 µL min-1 at an applied voltage of 12 ± 2 kV. In vitro characterisation and release studies using fluorescein dye as a model probe were carried out. RESULTS: SEM images confirmed the fibrous nature of the resulting matrix; showing an average fiber diameter of 298.32 nm. The electrospun mask was found to be advantageous due to this fibrous nature providing high active loading capacity whilst demonstrating 100% probe release within 60 min. Contact Angle hysteresis, thermal analysis and Fourier Transform Infrared Spectroscopy (FTIR) presented evidence of compatibility and stability of and within the formulation. CONCLUSION: Adapting the formulation of a commercial polymeric facemask into an electrospun facemask has shown the versatility of the electrospinning process; now successfully crossing over into the cosmetic industry.

INTRODUCTION: La couche cornée est le premier obstacle à l'hydratation de la peau par des produits cosmétiques. De nombreuses approches ont été adoptées pour surmonter cette entrave, dont l'une consiste à intégrer des cosméceutiques naturels dans les produits cosmétiques afin d'augmenter leur pouvoir hydratant. Ici, la formulation commercialisée d'un masque pour le visage a été modifiée par électrofilage de manière à développer des masques secs pouvant intégrer des cosméceutiques dans les pores de silice mésoporeuse présent dans le produit. MÉTHODES: Des solutions éthanoliques, contenant 40 % p/p du masque pour le visage commercialisé (masque peel-off 7th Heaven Dead Sea) et de la silice mésoporeuse ont été préparées et traitées électriquement à 30 µl/min_ 1, avec une tension appliquée de 12 ± 2 kV. Des études de caractérisation et de libération in vitro ont été menées, utilisant un colorant fluorescéine en tant que sonde. RÉSULTATS: Des images SEM ont confirmé la nature fibreuse de la matrice résultante, avec un diamètre de fibre moyen s'élevant à 298,32 nm. Le masque électrofilé a été jugé avantageux en raison de sa nature fibreuse, qui permet une capacité de charge élevée, ainsi qu'une libération de 100 % de la sonde dans les 60 min. L'hystérèse de l'angle de contact, l'analyse thermique et la spectroscopie infrarouge à transformée de Fourier (IRTF) ont permis d'identifier des preuves de compatibilité et de stabilité dans cette formulation. CONCLUSION: La possibilité d'adapter la formulation d'un masque pour le visage polymérique déjà commercialisé pour en faire un masque électrofilé montre la polyvalence du processus d'électrofilage, qui fait une apparition remarquable dans le domaine des cosmétiques.

Tissue engineered bone using select growth factors: A comprehensive review of animal studies and clinical translation studies in man.

There is a growing socio-economic need for effective strategies to repair damaged bone resulting from disease, trauma and surgical intervention. Bone tissue engineering has received substantial investment over the last few decades as a result. A multitude of studies have sought to examine the efficacy of multiple growth factors, delivery systems and biomaterials within in vivo animal models for the repair of critical-sized bone defects. Defect repair requires recapitulation of in vivo signalling cascades, including osteogenesis, chondrogenesis and angiogenesis, in an orchestrated spatiotemporal manner. Strategies to drive parallel, synergistic and consecutive signalling of factors including BMP-2, BMP-7/OP-1, FGF, PDGF, PTH, PTHrP, TGF-ß3, VEGF and Wnts have demonstrated improved bone healing within animal models. Enhanced bone repair has also been demonstrated in the clinic following European Medicines Agency and Food and Drug Administration approval of BMP-2, BMP-7/OP-1, PDGF, PTH and PTHrP. The current review assesses the in vivo and clinical data surrounding the application of growth factors for bone regeneration. This review has examined data published between 1965 and 2013. All bone tissue engineering studies investigating in vivo response of the growth factors listed above, or combinations thereof, utilising animal models or human trials were included. All studies were compiled from PubMed-NCBI using search terms including 'growth factor name', 'in vivo', 'model/animal', 'human', and 'bone tissue engineering'. Focus is drawn to the in vivo success of osteoinductive growth factors incorporated within material implants both in animals and humans, and identifies the unmet challenges within the skeletal regenerative area.

Evaluation of skeletal tissue repair, part 2: enhancement of skeletal tissue repair through dual-growth-factor-releasing hydrogels within an ex vivo chick femur defect model.

There is an unmet need for improved, effective tissue engineering strategies to replace or repair bone damaged through disease or injury. Recent research has focused on developing biomaterial scaffolds capable of spatially and temporally releasing combinations of bioactive growth factors, rather than individual molecules, to recapitulate repair pathways present in vivo. We have developed an ex vivo embryonic chick femur critical size defect model and applied the model in the study of novel extracellular matrix (ECM) hydrogel scaffolds containing spatio-temporal combinatorial growth factor-releasing microparticles and skeletal stem cells for bone regeneration. Alginate/bovine bone ECM (bECM) hydrogels combined with poly(d,l-lactic-co-glycolic acid) (PDLLGA)/triblock copolymer (10-30% PDLLGA-PEG-PLDLGA) microparticles releasing dual combinations of vascular endothelial growth factor (VEGF), chondrogenic transforming growth factor beta 3 (TGF-ß3) and the bone morphogenetic protein BMP2, with human adult Stro-1+bone marrow stromal cells (HBMSCs), were placed into 2mm central segmental defects in embryonic day 11 chick femurs and organotypically cultured. Hydrogels loaded with VEGF combinations induced host cell migration and type I collagen deposition. Combinations of TGF-ß3/BMP2, particularly with Stro-1+HBMSCs, induced significant formation of structured bone matrix, evidenced by increased Sirius red-stained matrix together with collagen expression demonstrating birefringent alignment within hydrogels. This study demonstrates the successful use of the chick femur organotypic culture system as a high-throughput test model for scaffold/cell/growth factor therapies in regenerative medicine. Temporal release of dual growth factors, combined with enriched Stro-1+HBMSCs, improved the formation of a highly structured bone matrix compared to single release modalities. These studies highlight the potential of a unique alginate/bECM hydrogel dual growth factor release platform for bone repair.

Evaluation of skeletal tissue repair, part 1: assessment of novel growth-factor-releasing hydrogels in an ex vivo chick femur defect model.

Current clinical treatments for skeletal conditions resulting in large-scale bone loss include autograft or allograft, both of which have limited effectiveness. In seeking to address bone regeneration, several tissue engineering strategies have come to the fore, including the development of growth factor releasing technologies and appropriate animal models to evaluate repair. Ex vivo models represent a promising alternative to simple in vitro systems or complex, ethically challenging in vivo models. We have developed an ex vivo culture system of whole embryonic chick femora, adapted in this study as a critical size defect model to investigate the effects of novel bone extracellular matrix (bECM) hydrogel scaffolds containing spatio-temporal growth factor-releasing microparticles and skeletal stem cells on bone regeneration, to develop a viable alternative treatment for skeletal degeneration. Alginate/bECM hydrogels combined with poly (d,l-lactic-co-glycolic acid) (PDLLGA)/triblock copolymer (10-30% PDLLGA-PEG-PDLLGA) microparticles releasing VEGF, TGF-ß3 or BMP-2 were placed, with human adult Stro-1+ bone marrow stromal cells, into 2mm central segmental defects in embryonic chick femurs. Alginate/bECM hydrogels loaded with HSA/VEGF or HSA/TGF-ß3 demonstrated a cartilage-like phenotype, with minimal collagen I deposition, comparable to HSA-only control hydrogels. The addition of BMP-2 releasing microparticles resulted in enhanced structured bone matrix formation, evidenced by increased Sirius red-stained matrix and collagen expression within hydrogels. This study demonstrates delivery of bioactive growth factors from a novel alginate/bECM hydrogel to augment skeletal tissue formation and the use of an organotypic chick femur defect culture system as a high-throughput test model for scaffold/cell/growth factor therapies for regenerative medicine.