含冠醚双亲共聚物纳米聚集体的制备及性能

Preparation and Properties of Crown Ethers Containing Amphiphilic Copolymer Nano-aggregates

模拟DNA化学结构,设计并合成了双亲共聚物聚(2,2'-(1,10-二氮杂-[18]冠-6-1,10-二基)二乙基5-((腺嘌呤-9-基)甲基)间苯二甲酸酯)(PDCAI),利用扫描电镜(SEM)观测了其在水溶液中的自组织形态,采用红外光谱法(FT-IR)研究了其与底物胸腺嘧啶(thymine)的氢键识别,并以变温红外进一步证实和考察了氢键的形成及断裂.同时,尝试了利用K+对PDCAI的自组织形态和氢键识别进行了调控,结果表明:在水溶液中PDCAI自发聚集成条带状聚集体,利用K+调控可使其聚集形态转变为棒状、纳米管状或螺旋棒状;在水溶液中底物thymine的C_2=O与PDCAI进行了氢键识别,而通过K+调控,氢键识别基变为thymine的C_4=O,说明PDCAI聚集形态的转变导致thymine在与其识别过程中进行识别构象的重组织.PDCAI的研制对研究揭示聚合物自发形成螺旋的分子特征、制备螺旋型聚合物、研制新型药物载体及功能调控具有参考意义.

In this paper, an amphiphilic copolymer poly（2,2＇-（1,10-diaza-[ 18]crown-6-1,10-diyl）diethyl 5-（（adenin-9-yl）- methyl）isophthalate） （PDCAI） was designed and synthesized by simulating the chemical structure of DNA. We observed its self-organized morphology in the aqueous solution and in potassium solution with scanning electron microscopy （SEM）, amphiphilic copolymer PDCAI spontaneously aggregated into strip aggregates in aqueous solution, and which could change into a rod, nanotube or helical rod aggregates in KNO3 solution. In addition, the molecular recognition between copolymer PDCAI and thymine substrate has been studied via FT-IR, and it is found that C2 = O of thymine had recognized with PDCAI through complementary nucleobases in aqueous solution, the C2 = O stretching band of thymine at 1737 cm- 1 shifted to 1710 cm-1 after recognition, however, the band of the C4=O of thymine did not change at 1677 cm 1. Meanwhile we attempted to regulate the molecular recognition of copolymer PDCAI with thymine substrate with K＋, we surprisingly found that hydrogen bonding occurs on C4=O of thymine when it recognized with PDCAI in KNO3 solution, the C4=O stretching band of thy- mine at 1677 cm-1 shifted to 1671 cm-1, however, the band of the C2=O of thymine did not change at 1737 cm-1 after recognition. It proves that the recognizing conformation of thymine re-organized during identification process due to the transition of aggregation form of PDCAI. And we further confirmed and studied the hydrogen bond formation and fracture process by variable temperature FT-IR, which formed at room temperature gradually broke while temperature rising from 25 ℃ up to 115℃, when temperature was above 115℃, hydrogen bonds broke completely, thymine and PDCAI return to their pre-recognition state. The formations of hydrogen bonds between adenine in the polymer and thymine substrate in nan- ospheres could enhance their interaction and loading capacity. The results have reference value for research of molecular characteristics of polymer which spontaneously formed spiral, preparation of helical polymer, and nucleic acid imitation drug carriers and its function regulation.