| 摘要: | 近年來，許多功能性細菌或微生物已經被研究並用於監測或改善環境問題，而當微生物遭遇紫外線、極端溫度、酸鹼環境或抗生素等威脅，將會使細胞生命力降低甚至死亡，而影響微生物的工作效率，所以常利用具生物相容性的材料塗層於微生物加強其抵抗惡劣環境的能力，目前已推進至“Cyborg Cell”的時代，常用的材料包括金屬奈米顆粒、二氧化矽、碳酸鈣等無機物，提供微生物堅固的保護層。與其他材料相比金屬有機骨架材料 (MOFs) 因具規則排列的孔洞以及其晶體大小的可調控性和水熱穩定性，為近年來新興材料之一。本研究將MOFs與微生物結合成生物複合材料，利用ZIF-90作為外殼保護大腸桿菌，探討封裝於微米級單晶ZIF-90內的大腸桿菌抵擋惡劣環境的能力。結果顯示，利用掃描式電子顯微鏡鑑定其粒徑大小約7-8微米；更進一步以共軛焦雷射掃描顯微鏡證實大腸桿菌成功地被封裝於金屬有機骨架材料中(E. coli@ZIF-90)。將E. coli@ZIF-90置於抗生素—氨苄青黴素的環境測試，證明藉由ZIF-90的孔洞 (3.5 Å) 選擇性抵抗外部的氨苄青黴素 (4.2×7.1×10.9 Å3) 保護大腸桿菌。此外也使用奈米級多晶ZIF-90或ZIF-8塗層於大腸桿菌表面，並從掃描式電子顯微鏡的影像進行觀察鑑定，但因合成環境嚴苛使大腸桿菌的存活率極低，未來仍需要改善合成環境及探討其存活率，藉以比較微米級單晶封裝與奈米級多晶塗層之差異。;In recent years, functional bacteria or microorganisms have been studied and used as biosensor to overcome environmental problems. Microorganisms have been armored by biocompatible materials with functionalization to resist harsh environments such as ultraviolet radiation, extreme temperatures, acid or base and antibiotics, and pushed the application of microorganism into the era of the “cyborg cells”. Comparing Metal Organic Frameworks (MOFs) with common materials like metal nanoparticles, silica or calcium carbonate, the MOFs has regular pore structure, tunable crystal size and high hydrothermal stability. Herein, we based on our previous reported that a de novo approach, i.e., synthesis under water and mild conditions, for encapsulating the Escherichia coli (E. coli) into ZIF-90 single crystals, E. coli@ZIF-90, as protective structure against harsh conditions. Spectral analysis such as scanning electron microscopy (SEM) images indicated that the morphology of biocomposites are uniform crystals with particle size of 7−8 μm. Moreover, the confocal microscopy was carried out to confirm that the E. coli were embedded in ZIF-90 crystals which provided shelter for the biocomposites against antibiotics. Consequently, E. coli could readily regain vitality after the removal of MOF protection. In addition, making a comparison between single crystals of E. coli@ZIF-90 and E. coli biocomposites coated by nanoscaled polycrystalline ZIF-90/ZIF-8; however, the survival rate of E. coli was low probably due to the harsh condition for coating by polycrystalline MOFs. Thus, the optimal synthetic condition for enhancing the vitality of E. coli which is protected by polycrystalline ZIF-90/ZIF-8 need to be further studied in the near future. |
