藉由胜肽輸送進入活細胞內溶小體之具有酸鹼值偵測能力的中孔洞二氧化矽奈米粒子

Abstract

具中孔洞的二氧化矽奈米粒子作為平台可有效地運輸酵素抵達受損的組織，因酵素裝載在此多功能的中孔洞二氧化矽奈米粒子裡，能夠增加在血液中的循環時間、有更精準的標靶能力以及保護酵素免於免疫反應的發生。在這個研究裡，此中孔洞的二氧化矽奈米粒子被修飾上兩個酸鹼值靈敏的螢光染劑，分別是fluorescein isothiocyanate (FITC, pKa = 6.7)和oregon green succinimidyl ester (OG, pKa = 4.8)，以及一個參考染劑為rhodamine B isothiocyanate (RITC)，使其成為一個pH值感測器並具有一個寬廣的酸鹼值偵測範圍 (pH = 4.2 ─ 7.4)，因此我們可以利用單一粒子追蹤的顯微技術來做酸鹼值的即時偵測，藉此提供一個新穎的方式來辨識此中孔洞二氧化矽奈米粒子在活細胞中的位置。在另一方面，此具有酸鹼值感測能力的中孔洞二氧化矽奈米粒子被修飾上具有溶小體標靶能力的胜肽鏈 (YXXØ)可作為酵素取代治療的生醫應用，我們展示了酸鹼值感測的中孔洞二氧化矽奈米粒子對於細胞環境pH值的即時傳訊是一個有用的技術來評估其在活細胞中的移動途徑，而藉著YXXØ胜肽的功能，此連接著YXXØ的中孔洞二氧化矽奈米粒子確實能夠到達溶小體，相較於裸露的中孔洞二氧化矽奈米粒子幾乎只累積在細胞質的環境。酵素取代治療已經在臨床上被使用來治療溶小體囤積症，然而目前為止，仍然有許多的問題尚待解決，其中像是造成各種副作用的免疫反應以及不佳的治療效果等等，因此具有溶小體標靶能力的中孔洞二氧化矽奈米粒子將會是一個有潛力的奈米載體作為改善酵素取代治療對於溶小體囤積症的效果。

Mesoporous silica nanoparticles (MSNs) as a platform can efficiently transport enzymes to the impaired tissues because enzymes loaded in multiple functional MSNs can increase the circulation time in blood, have more precisely targeting ability and protect them from some immune reaction. In this study, MSNs were made as a pH nanosensor which has a broad pH-sensing range from 4.2 to 7.4 by conjugating two pH-sensitive fluorescent dyes, fluorescein isothiocyanate (FITC, pKa=6.7) and oregon green succinimidyl ester (OG, pKa=4.8), and a referent dye, rhodamine B isothiocyanate (RITC) onto MSNs. So we can provide a novel method to identify the localization of the MSNs in living cells with real-time pH detection by single particle tracking microscope technique. In the other hand, the pH-sensing MSNs were modified with lysosomal sorting peptides (YXXØ) which can target lysosomes for potential enzyme replacement therapy. We showed that the real-time signaling of the environment pH values from the pH-sensing MSNs is a useful technique for evaluating the pathway of them in living cells, and the specific peptide-conjugated MSNs were indeed delivered into lysosomes by the function of the YXXØ sequences. Enzyme replacement therapy has been used clinically for treating lysosomal storage diseases. However there are still many problems such as immune reaction causing much side-effect need to be solved. So the lysosome-targeting MSNs will be a promising nanocarrier for improving the enzyme replacement therapy to lysosomal storage disease.