Preparation Of Hyaluronic Acid Dissolving Microneedles And Their Application In Percutaneous Tumor Theranostics

Microneedle technology is a new type of transdermal drug delivery system which has been widely applied in the field of transdermal drug delivery because of it's efficient, safe and painless. Compared to traditional microneedle drug delivery system, dissolving microneedle drug delivery has the advantage of low cost, good safety, high efficiency and controlled drug release. Dissolving microneedles are usually prepared by micromolding method. However, the traditional preparation of microneedle mold is difficult, high-cost and complex. On the other hand, it usually requires external methods such as heating, centrifugal, ultraviolet light etc. to prepare dissolving microneedles. These harsh conditions often cause the loss of products or the destruction of the molecular structure of the loaded drug. This research work was carried out to explore a simple, controllable, and low-cost preparation method of microneedle mold and a simple, gentle, efficient and large-scale preparation method of dissolving microneedles. The main contents include the following two aspects:(1) With concentric circles array as the mask, the conical array microneedle molds were prepared with well-defined structure, smooth surface and controlled size by laser etching method. With these microneedle molds, dissolving microneedles made of hyaluronic acid were prepared, demonstrating the applicability of the microneedle mold.(2) Hyaluronic acid-based dissolving microneedles with different mechanical strength were prepared by micromoulding method under room temperature and negative pressure. Meanwhile, the microneedles were loaded with gold nanocages, enabling the photothermal therapy of the skin tumors. Furthermore, doxorubicin, a chemotherapy drug, was entrapped simultaneously with gold nanocages or nanorods into the microneedles to realize the combination of the tumor chemotherapy and the photothermal therapy.