Development of cosmetic textiles for body care with biological benefits

Abstract

This thesis is concerned with the development of cosmetic textiles for body care with biological benefits. The research is aimed at creating a reliable substance delivery system for cosmetic textiles using the microencaspulation technique. Different fabrication techniques with the aid of pre-treatment and post-treatment processes have been investigated to embed the newly developed microcapsules in textile materials with satisfactory performance. A systematic characterisation system has been successfully established for the evaluation of cosmetic textiles which provides guidance for the commercial sectors to assessing their performance in an objective and safety manner. The study covers five related aspects, namely (1) development and optimisation of microencapsulation systems for the skin caring substances, (2) characterisation of microcapsules in terms of physical and chemical properties, (3) in vitro and in vivo biological analysis of microcapsules, (4) development of cosmetic textiles containing microcapsules using various fabrication techniques, (5) establishment of a systematic characterisation system for cosmetic textiles. Chitosan-based oil-in-water microencapsulation system was successfully developed for the encapsulation of oil-soluble substances using the coacervation technique. Optimisation of the of chitosan microencaspulation system was conducted with the aid of Orthogonal Array Testing Strategy in order to improve its encapsulation efficiency. Under the optimum condition, the encapsulation efficiency could be maximised to 95% approximately. A series of advanced instruments such as Scanning Electron Microscope, Fourier Transform Infrared Spectrometer, Particle Size Analyser and Zeta Sizer had been employed for the characterisation of microcapsules. The stability and controlled release properties of microcapsules were investigated. Cytotoxicity test was performed to study the biological safety with respect to human skin cells HaCaT skin keratinocytes. Gelatin-based water-in-oil microencapsulation system was successfully developed using the emulsion-hardening technique for the encapsulation of water-soluble substances. Optimisation of the gelatin-based microencaspulation system was carried out to improve the particle size of microcapsules. The product yield, surface morphology and particle size distribution of the newly developed microcapsules had been analysed thoroughly. The release rate of ingredients was also quantified using the UV-Visible Spectrophotometry. The stability of microcapsules with respect to different humidity and temperature was investigated. The cytotoxicity level of the so synthesis microcapsules was investigated in order to determine the toxic effect caused by formaldehyde which acted as the crosslinking agent during the synthesis process. The release mechanisms of both the chitosan-based and gelatin-based microcapsules were also proposed based on their characteristics. Different types of drugs including hydrocortisone and gallic acid were successfully encapsulated using the chitosan-based and gelatin-based microencapsulation system respectively. The corresponding biological responses of the drug-loaded microcapsules were analysed. Different fabrication techniques including (1) Exhaustion, (2) Padding, (3) Printing and (4) Spraying were used to embed the newly developed microcapsules in textiles. Atmospheric pressure plasma treatment was employed to pre-treat the fabric samples aiming to enhance the uptake of microcapsules at the fibre surface. Binder fixation was employed as the post-treatment process to enhance the durability of microcapsules attached to fibres. An in vitro skin model was established to assess the performance of microcapsules-coated textile materials in a safety and objective manner. Systematic characterisation was also established to assess the performance of the commercially available cosmetic textile agents as well as cosmetic textiles. The systematic characterisation so developed consisted of three major categories, namely (1) material characterisation and ingredient identification, (2) fabric performance testing, and (3) biological safety and response to human skin.