Electrospinning of cyclodextrin functionalized nanofibers and their applications
Electrospinning is a widely used versatile method to produce nanofibers with high surface to volume ratio and porous structure. Owing to the unique properties, electrospun nanofibers are of great importance as a carrier matrix for drugs; antioxidant, and antibacterial agents, flavour/fragrances. Though polymers are material of choice for producing electrospun nanofibers, it is likely to obtain nanofibers from low molecular weight molecules. Cyclodextrin (CDs) are intriguing molecules having the capability of forming inclusion complex (IC) with numerous guest molecules such as drugs, food additives, flavour/fragrances, antioxidant and antibacterial agents. Therefore, CD-ICs enhance solubility, reduce volatility, and provide controlled release of the guest molecules. Integrating CD-ICs with electrospinning opens a new door to produce remarkable materials. In this thesis, nanofibers containing CD-ICs of bioactive agents including antioxidant/antibacterial and flavour/fragrance molecules were produced via electrospinning technique. Firstly, CD-ICs of antioxidant/antibacterial compounds (gallic acid, α-tocopherol, quercetin, and thymol) were synthesized and then, added into polylactic acid or zein solutions to produce CD-IC incorporated electrospun polymeric nanofibers. Afterwards, the release behavior, antioxidant and antibacterial activity of these nanofibers were investigated. In addition, the potential use of these nanofibers as active food packaging and delivery material was revealed by packing meat samples by these nanofibers. Secondly, electrospun nanofibers were developed as a releasing material from CD-ICs of volatile flavour/fragrance molecules (geraniol, limonene, and linalool) without using polymeric matrix. The preservation of volatile compounds is shown to be possible to a great extent with antibacterial CD-IC nanofibers. Furthermore, the shelf life of flavour/fragrance molecules has been enhanced at least 50 days by CD-IC nanofibers. Finally, for the first time in the literature core-shell nanofibers were designed by using CD-IC of curcumin, an antioxidant molecule and polylactic acid solutions as core and shell, respectively. The ability of core-shell nanofibers as a drug delivery carrier was suggested by release and antioxidant activity tests. To conclude, CD-IC incorporated electrospun nanofibers produced by three different approach is shown to be used as efficient material for various applications particularly for food packaging and drug delivery.