Owing to the high market values of natural sunstones in Oregon, a kind of artificially diffused red feldspar exhibited at the Tucson Exhibition at the beginning of this century, whose color origin is the same as that of natural sunstone (copper nanoparticles). However, the details of the artificial diffusion process are less disclosed, there is no systematic method to obtain such gemstones. In this paper, we developed the high-temperature copper diffusion process for the surface recoloring of faceted labradorites, which are partly buried in the diffusant. By optimizing the experimental parameters of high-temperature copper diffusion, we successfully recolored the faceted labradorites to red and light red. The gemological and spectroscopic characteristics of the recolored faceted labradorite were further characterized. The red and light-red faceted labradorites exhibited the unique surface plasmon resonance absorption peaks of copper nanoparticles near 580 nm, which is the origin of red color. The typical inclusions formed in the faceted labradorite is in the shape of “fire cloud”. The interface of red and light-red faceted labradorite that is in contact with the diffusant is less contaminated, we believe that the contamination could be further reduced or eliminated by optimizing the high-temperature copper diffusion process. The way that the sample is in contact with the diffusant partly is versatile and promising in the surface treatment of materials that have already been processed.Keywords:labradorite;faceted;copper diffusion;recoloring
Hair-related disorders are currently widely concerned issues for not only the scientific society but also the public attentions. Microneedle-based drug delivery system has been regarded as a promise hair follicle-targeted drug delivery approach, largely because they can effectively penetrate the stratum corneum barrier and deliver drugs to hair follicles within dermis. However, the currently reported microneedles for treating hair-related disorders usually rely on rigid backings, showing poor adaptability to the curved scalp and thereby restricting their usability for hair follicles targeted drug delivery. To this end, this study utilized sodium alginate and polyvinylpyrrolidone to construct a scalp-curvature-conforming microneedle with flexible backing. Subsequently, Psoralea corylifolia extract (PE) was loaded into the microneedles to investigate its capability in delivering PE to the hair follicle site for treating leukotrichia associated with vitiligo. These PE-loaded microneedles can effectively conform to the curvature of skin, enhancing the efficiency of microneedle insertion and ensuring stable drug delivery. Moreover, animal studies demonstrate that the PE loaded microneedles can effectively penetrate the stratum corneum, benefiting the drug delivery to hair follicles located site, and consequently showing a successful inhibition of hair graying. In summary, the present study reports a design and preparation of scalp-curvature-conforming microneedle. This design may offer a potential solution for efficient drug delivery using microneedles to the curved skin.
危险品化学品经营许可证（带存储）