烷基鏈長與聚集誘導發光團對有機自組裝奈米材料的影響

Abstract

近年來，科學家對分子的掌握日漸成熟，更進一步就是控制分子間的弱作用力，這一門領域便是自組裝材料的起源。本論文第一部分研究方向為探討烷基鏈長度對萘四羧酸二醯亞胺雙胜肽自組裝材料的影響，我們選用了甲胺、乙胺、正丙胺、正丁胺及正辛胺來改變萘四羧酸二醯亞胺的脂肪鏈長和搭配合成酪氨酸和苯丙氨酸來提高它的應用價值，經由改變碳鏈長度可以發現一些物理性質的不同。在成膠臨界pH方面，碳鏈由長變短酸鹼值則是由鹼變酸。臨界成膠濃度則為碳鏈越短所需濃度越高，凝膠溶液轉換溫度與流變性質則是碳鏈越長所需溫度越高儲存模數(G′)越大。在螢光性質方面，濃度越高螢光強度下降且伴隨紅位移現象產生，表現出有聚集淬滅螢光效應的性質。 第二部分我們研究的主要方向於利用合成具有生物功能性的胜肽序列與能夠形成聚集誘導發光的四苯基乙烯(TPE)分子結合，我們挑了DGEA和RGD這兩種生物序列。在DGEA方面，TPE-GDGEA其1 wt%無法成膠，3 wt%的成膠pH值為酸性，TPE-FDGEA它在1 wt%成膠的pH值為酸性，其3 wt%成膠pH值則為中性。這兩個材料的凝膠溶液轉換溫度和流變特性皆是TPE-FDGEA 3wt%最高，TPE-GDGEA 3 wt%的結構型態為奈米緞帶而低濃度及TPE-FDGEA則是奈米纖維。在生物實驗方面，由於TPE-FDGEA 3 wt%可以在中性成膠使得它的應用性比TPE-GDGEA好。RGD方面我們另外找了RGE作為對照組，分別合成TPE-FRGD及TPE-FRGE，在成膠方面兩者皆在1 wt%酸性成膠，凝膠溶液轉換溫度及流變性質皆是TPE-FRGD較大，而其結構都是奈米纖維。另外變水比例(Water fraction)實驗顯示兩者也皆具有聚集誘導發光的效應。而在生物實驗方面，兩者皆能進入細胞內產生螢光，在未來可以發展為一個前瞻性的新穎材料，可望在生醫領域上有相當的應用價值及發展潛力。

Recently, research of molecules behavior gradually matured, further controlling strength or weakness of molecular interaction, which is the origin of self assembly materials. The first part in my study, we discussed the effect of changing alkyl chain length on naphthalene diimide (NDI) to dipeptide self assembly. We chose methylamine、ethylamine、n-propylamine、n-butylamine and n-octylamine to be the aliphatic chain length on naphthalene diimide, connecting tyrosine and phenylalanine as peptide sequence to improve the value of application. In addition, we discovered different physical properties by chaning alkyl chain length. Carbon chains length affected critical gelation pH. As the length was decreased, the critical pH value changed from higher to lower. Minimum gelation concentration (MGC) increased with the chain decrease of carbon length. Sol-gel transition temperature and storage modulus (G’) on rheology increased as carbon chains increasing. In photo-luminescence (PL), fluorescence intensity decreased with increasing concentration and happened red shift. This demonstrated aggregation-caused quenching (ACQ) properties. In the second part, we synthesized biofunctional peptid sequence conjugated with tetraphenylethene (TPE) to produce aggregation-induced emission (AIE). We selected DGEA and RGD as biological sequence. 1 wt% TPE-GDGEA could’t form hydrogel but formed hydrogel at 3 wt% under acidic environment. 1 wt% TPE-FDGEA formed hydrogel under acdic environment and hydrogel at 3 wt% was formed under neutral environment. 3 wt% TPE-FDGEA has the hightest on sol-gel transition temperature and rheology. The structure of 3 wt% TPE-GDGEA hydrogel present naroribbons while TPE-GDGEA hydrogels under and all concentraitons including TPE-FDGEA were nanofibers. For biological experiments, 3 wt% TPE-FDGEA was better than TPE-GDGEA, because 3 wt%TPE-FDGEA could form hydrogel under netural environment. In order to investigate the difference between RGD and RGE, we also synthesized TPE-FRGD and TPE-FRGE. The both 1 wt% TPE-FRGD and 1 wt% TPE-FRGE formed hydrogel under acidic environment, while TPE-FRGD on sol-gel transition temperature and rheology was higher than TPE-FRGE and their structure present nanofibers.In addition, water fraction experiment indicated the both TPE-FRGD and TPE-FRGE displayed the AIE properties. On biological experiments, the both could enter into cells and performed fluorescence. In the future, the two TPE derivatives develop a prospective and novel materals with applying in the field of health and medicine.