【摘要】：現(xiàn)階段所報道固定生物催化劑的載體多是由層層自組裝過程(LBL self-assembly)所制備的聚合物囊泡/微囊,這種納、微米反應(yīng)器適用一些簡單的催化體系,對于一些更加復(fù)雜的或者含不相容元素的體系來說,具有一定的局限性。本課題組首次利用靜電紡絲技術(shù),制備具有中空結(jié)構(gòu)的微囊,并成功用于多酶催化體系在其內(nèi)腔室的原位封裝。這種新型的固定多酶體系與傳統(tǒng)納、微球相比,其微米尺度的腔室可以為所包埋酶提供一個極其穩(wěn)定的微環(huán)境;同時由于具有良好的分散性更有利于催化反應(yīng)。本論文的研究主要包括以下幾個部分;1.采用同軸電噴技術(shù)制備聚氨酯(Polyurethane,PU)中空微囊。考察內(nèi)、外相電紡液的組成及摻雜聚合電解質(zhì)對中空微囊形貌及內(nèi)外徑的影響。以含水量20φ%(v/v)甘油溶液作為內(nèi)相電紡液,以溶于N,N二甲基乙酰胺(DMAC)的10 wt%聚氨酯溶液作為外相電紡液,內(nèi)外相流速分別為0.05 mL/h和1.0 mL/h,電壓為20 kV左右,針頭到接收板距離為40 cm,溫度為25℃,濕度為10%條件下,可以制備出結(jié)構(gòu)均一的中空微囊。2.以南極假絲酵母脂肪酶(CALB)、葡萄糖氧化酶(GOD)和辣根過氧化物酶(HRP)作為模型反應(yīng),將其定位組裝于中空微囊的內(nèi)腔室、壁層和外表面,通過同軸電紡技術(shù)結(jié)合層層自組裝和離子配對技術(shù)。研究結(jié)果顯示,催化體系中封裝在內(nèi)腔室和吸附在外表面的單酶活性收率均保持在68%以上,摻雜在壁層的單酶活性收率同樣保持在48%以上。定位組裝催化體系的活性收率為28%,重復(fù)使用8次后活性仍保持在初始活性的70%,在60℃的半衰期比游離酶提高了 12倍。這種組裝方法極大的提高催化體系的穩(wěn)定性,并且具有操作簡單、條件溫和、容易制備等優(yōu)點;同時通過這種組裝方法簡單調(diào)整溶液PH以及選擇合適的表面活性劑,可以實現(xiàn)多酶催化體系以一種我們希望的反應(yīng)次序定位組裝于聚氨酯中空微囊上。3.通過設(shè)計特定的噴絲頭以及同軸電噴參數(shù)的優(yōu)化,制備三腔室中空微囊。將三酶體系的每種酶原位包埋于微囊的三個腔室,構(gòu)建基于三腔室微囊的多酶催化體系。這是首次通過同軸電紡技術(shù)制備具有生物兼容性的三腔室微囊,它的性能通過級聯(lián)反應(yīng)的催化效率進行表征。此催化體系中單酶活性收率均保持在60%以上,多酶催化體系的活性收率保持在14.65%,級聯(lián)反應(yīng)的穩(wěn)定性也獲得極大的提高。這種可以實現(xiàn)空間分離的多腔室微囊,在固定三酶催化體系(CALB/GOD/HRP)的研究中并沒有展現(xiàn)它結(jié)構(gòu)上的優(yōu)越性。它在兩相體系或者含有不相容元素的多酶催化體系或許會能夠展現(xiàn)它所特有的結(jié)構(gòu)優(yōu)勢。
[Abstract]:At present, the carriers of immobilized biocatalysts are mostly polymer vesicles / microcapsules prepared by layer upon layer self-assembly process (LBL self-assembly). This nano-micron reactor is suitable for some simple catalytic systems. There are limitations to more complex or incompatible systems. For the first time, the microcapsules with hollow structure were prepared by electrostatic spinning technique, and successfully used in the in-situ encapsulation of multi-enzyme catalytic system in the inner chamber. Compared with the traditional nanospheres and microspheres, this new type of immobilized multi-enzyme system can provide an extremely stable microenvironment for the encapsulated enzymes, and it is more favorable for the catalytic reaction because of its good dispersity. The research of this thesis mainly includes the following parts. Polyurethane (Polyurethane,PU) hollow microcapsules were prepared by coaxial electrospray technique. The effects of the composition of external phase electrospun solution and doped polyelectrolyte on the morphology and inner diameter of hollow microcapsules were investigated. Water content 20 蠁% (v / v) glycerol solution was used as inner phase electrospinning solution, and 10 wt% polyurethane solution dissolved in N dimethyl acetamide (DMAC) was used as external phase electrospinning solution. The flow rate of internal and external phase was 0. 05 mL/h and 1. 0 mL/h, voltage was about 20 kV, respectively. When the distance from the needle to the receiving plate is 40 cm, the temperature is 25 鈩，

本文編號：2260177