| Summary: | 博士 === 國立臺灣師範大學 === 化學系 === 99 === The biomedical applications of nanomaterials in imaging, drug delivery, and therapy have led to ever-growing developments in the past decades. In this work, we combined the second harmonic generation of ZnO nanoparticles and the autofluorescence of the stratum corneum to image the penetration of ZnO nanoparticles under the chemical enhancer conditions of oleic acid, ethanol and oleic acid-ethanol. In addition to qualitative imaging, the microtransport properties of ZnO nanoparticles were quantified to give the enhancements of the vehicle-to-skin partition coefficient, the second harmonic generation intensity gradient and the effective diffusion path length. The results showed that oleic acid, ethanol and oleic acid-ethanol were all capable of enhancing the transdermal delivery of ZnO nanoparticles by increasing the intercellular lipid fluidity or extracting lipids from the stratum corneum.
Furthermore, with no additional staining, the two-photon image showed that fluorescent nanoparticles penetrated and resided within interlamellar space of cornea stroma when corneal epithelium barrier was injured. In vitro cytotoxicity test using bovine corneal stromal cells incubated with nanoparticles indicated that the cell viability decreased significantly as the nanoparticles concentration and incubation period increased. Moreover, two-photon imaging showed that nanoparticles can retain within cornea up to 26 days in an in vivo mouse model. On the basis of our in vivo and in vitro data, we conclude that nanoparticles can penetrate and retain within cornea long enough to cause consequential cytotoxicity, under the circumstance that corneal epithelium barrier is injured.
In drug delivery applications of nanomaterials, the conjugates of gold nanorods and the model drug, fluorescein isothiocyanate (FITC), embedded inside polyelectrolytes (GNRs/FITC@PLE) were synthesized to study the release kinetics of FITC under femtosecond near-infrared (NIR) laser irradiation. The release of FITC from the conjugates was induced by the heat generated from gold nanorods under laser irradiation. The concentration of released FITC was measured as the time of continuous and periodic laser irradiation was varied. Within 5 min of the laser exposure, the release rates of FITC exhibited zero-order and first-order kinetics under continuous and periodic irradiation, respectively. Furthermore, a drug release system was designed based on the conjugates of gold nanorods and the anticancer drug, paclitaxel (PTX), embedded inside polyelectrolytes (GNRs/PTX@PLE). The release of PTX from the conjugates was triggered by NIR laser irradiation, and the inhibition rates of breast cancer cells showed strong dependencies on the irradiation modes and time.
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