利用高分子微針作為一可自我施行且無痛之生物巨分子藥物輸送方法已廣為人知，其相較於金屬或矽質微針除免除了使用上之安全疑慮亦可減少生醫廢棄物之危害。在本研究中，將以幾丁聚醣高分子做為微針基質，期望開發出一種兼具生物可降解性及藥物或疫苗佐劑功效之生物相容性藥物傳輸裝置。 首先，利用聚二甲基硅氧烷 (polydimethylsiloxane, PDMS) 對金屬微針主結構翻模製造所需之微模具 (micromold)，並於常溫常壓之環境下，將濃度 10% (w/w) 且約為中性 (pH = ~6.0) 之幾丁聚醣溶液以離心等溫和的製程，經灌模後製成幾丁聚醣高分子微針。由機械壓縮測試結果繪製施力與微針形變之關係圖，得知若微針的深寬比越小，其機械強度越強。 由體外豬皮穿刺測試結果發現，較低深寬比的微針其穿刺比例高達98.0 ± 3.5%，穿刺深度為150.8 ± 5.5 μm，可成功穿越角質層、到達大量可引發免疫反應的抗原呈現細胞所存在之表皮層。在體外藥物釋放實驗中，由穿刺皮膚六小時後的釋放曲線可知幾丁聚醣微針能夠分別提供小分子和大分子模式藥物 (model drug) 84.1 ± 6.7% 和 79.8 ± 3.2% 的釋放量，其中，藥物釋放比例與微針接觸皮膚表面積和包覆藥物的分子量有直接的關係。 研究中另以溶菌酶 (Lysozyme) 作為生物活性分子之模型，從實驗結果得知經幾丁聚醣高分子微針包覆之溶菌酶，在室溫下保存一個月後仍可兼具活性和穩定性。 總體而言，本研究證實幾丁聚醣微針可溫和地包覆生物大分子，並於刺穿皮膚後逐漸釋放其所包覆之藥物。

Polymeric microneedles have been known to serve painlessly self-administration of biomacromolecules without leaving biohazardous wastes. The use of chitosan as microneedle matrix, in this study, is expected to provide a biodegradable and biocompatible drug release device that can also act as adjuvant for vaccine encapsulated inside. Chitosan microneedles were fabricated using gentle processes, in which centrifugation in ambient temperature and pressure was applied to cast the 10% (w/w) of chitosan solution (pH = ~6.0) to fill the mold, which was replicated from microneedle master structure using cured PDMS. Mechanical compression test has been done to measure the strength of microneedles by plotting the displacement of needles with the force, where the microneedles with lower aspect ratio (i.e. 2) have the greater mechanical strength. The in vitro porcine skin insertion test has showed the microneedles with lower aspect ratio were able to make 98.0 ± 3.5% insertion rate and 150.8 ± 5.5 μm penetration depth, crossing the epidermis layer where the antigen-presenting cells exist. In vitro drug release profile shows the chitosan microneedles were able to deliver both low and high molecular weight model drugs as much as 84.1 ± 6.7% and 79.8 ± 3.2%, respectively, within 6 hours skin insertion. The drug release rate relied on the contact surface area of microneedle inserted into the skin and on the molecular weight of loaded drugs. Lysozyme, encapsulated in chitosan microneedles as a model of biomacromolecules, was shown to retain its stability after storage for 1 month at room temperature. Overall, this study demonstrates the ability of chitosan microneedles to gently encapsulate biomacromolecules, insert into skin and release the load.

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