狂犬病是一種由病毒引起之人畜共患傳染病，由於狂犬病疫苗的成本高昂，加上疫區普遍醫療資源不足，因此在狂犬病盛行的區域防疫始終無法普及。本研究主要探討利用幾丁聚醣微針是否能有效節省狂犬病疫苗劑量，或是降低接種次數，成為一種成本較便宜且方便一般民眾施打的狂犬病疫苗貼片。以具有免疫佐劑 (adjuvant)功效的幾丁聚醣為微針主體，將狂犬病疫苗均勻的包覆在內，加上後端結合聚乙烯吡咯烷酮/聚乙烯醇水溶性高分子支撐軸，在微針刺入皮膚後，由組織液溶解後端支撐軸，僅留前端幾丁聚醣微針在皮膚內持續釋放疫苗。由體外豬皮及體內大鼠穿刺實驗證實，此微針貼片具有足夠機械強度可刺穿皮膚角質層，使其鑲嵌於富含抗原呈現細胞的真皮層中(深度約 800 μm)，將疫苗標的傳輸至此，能刺激更多的抗原呈獻細胞，引發較強的免疫反應。將微針包覆接枝螢光之疫苗穿刺於老鼠背部皮膚，利用非侵入式活體分子影像系統以及多光子共軛焦顯微影像系統，證實此微針可在活體內緩慢降解並持續釋放疫苗至少 21 天，達到類似多次針劑補強(boost)注射之效果，延長免疫作用時間。以小鼠進行免疫試驗，由結果顯示添加10%海藻糖的微針組只需接種一次，即可產生與肌肉注射接種兩次相當的抗體量，但誘發抗體時間較晚，而添加30%海藻糖的微針組別，由於海藻糖的高度親水性，可加速疫苗之釋放，不但能與肌肉接種組同樣快速誘發抗體產生，且能維持高抗體濃度達12週。本研究證實，以幾丁聚醣微針傳遞疫苗，有機會節省疫苗劑量和減少接種次數。期許本研究開發之微針能為狂犬病疫苗接種帶來更多的便利，解決開發中國家因醫療資源不足，無法即時或預防接種之問題。

　　In this study, we encapsulated the rabies vaccine into the chitosan (CS) microneedles (MNs) to evaluate if there was the dose-sparing effect and if it could reduce the number of doses to administer. We expected the rabies vaccine (RV) loaded CS MNs, could become a more affordable and an easier-to-administration for the public. The rabies vaccine was encapsulated into the CS MNs, which functioned as an adjuvant, and combined with a dissolvable Polyvinylpyrrolidone/ Poly(vinyl alcohol) (PVP/PVA) supporting array. After the MNs were inserted into the skin, the skin interstitial fluid dissolved the supporting array, and the CS MNs were left within the skin for sustained release of vaccine. The in vitro and in vivo skin insertion tests showed that this MN could be inserted into skin and then embedded between epidermis and dermis (the penetration depth was approximately 700-800 µm), where were rich in antigen-presenting cells (APCs). If the vaccine was delivered to the regions precisely, it could spur abundant APCs, and thus, it could active a better immune response. When the rabies vaccine with fluorescence-loaded CS MNs was applied to the mice skin in vivo, confocal microscopic and non-invasion in vivo imaging system (IVIS) images showed that the MNs gradually degraded and released the rabies vaccine at least 21 days; the effect was similar to the receiving booster doses and might prolong the immune response. Comparing the traditional intramuscular immunization (I.M.) (2 doses of 4 % RV on days 0 and 7) to the mice immunized by MNs (a single dose of 4% RV on day 0 or 2 doses on day 0 and 7 ) in the immunization test of mice, we found that I.M. (two doses) and MNs (single dose) groups could produce about the equal amount of antibody levels, which indicated the group of MNs used only the 1/2 dose vaccine of the I.M. group .The MNs (two doses) groups could produce higher antibody than the I.M. groups at the same dose. Moreover, HT MNs (contain 30 % trehalose, single dose) induced higher and longer anti-rabies antibodies response than I.M. (two doses) from 4 weeks to 8 weeks after immunization. We concluded that there was a possibility to have the dose-sparing effect and could reduce the number of doses to administer by using this CS MNs to deliver the rabies vaccine.

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