pH敏感型智能高分子单链力学性能研究

doi:10.6023/A20110529

摘要/Abstract

pH敏感高分子是智能高分子的重要分支, 基于其体积、质量或者弹性等参数随pH值变化的性质, 可以应用在生物、化学和微/纳机械等多个领域. 现有研究多集中在应用领域, 缺乏从更深层次的机理上的研究, 因此亟需在分子水平上对pH敏感高分子的环境敏感机理进行研究. 本工作基于控制变量实验法, 利用基于原子力显微镜的单分子力谱技术(SMFS)对pH敏感型高分子聚丙烯酸(PAA)在pH变化前后的单分子力学弹性进行对比研究. 结果表明, 随着pH值增加, PAA单链构象经历了从塌缩到完全伸展的改变, 并获得了不同构象之间的能量差, 由此提出了一种全新的分子马达(开关)的设计概念. 本工作的研究结果有望为设计多重响应新型聚合物和智能传感器提供理论基础和数据支持.

关键词: 单分子力谱, pH敏感高分子, 构象变化, 分子马达, 分子开关, 智能传感器

As an important part of smart materials, the volume, mass, or elasticity of pH-sensitive polymers can shift with pH values. Based on the feature, the pH-sensitive polymers can be used in many fields such as biology, chemistry and micro/ nano electromechanical system. Previous researches are based on the development and utilization of the known properties of functional smart materials, the mechanism of pH-sensitivity at the single-molecule level is still unclear. Based on the single molecule force spectroscopy, the single-chain mechanics of a typical pH-sensitive polymer, polyacrylic acid (PAA), in the buffer solution with different pH values have been studied. In order to reduce the influence of other factors on the experimental results, the buffer solution used in the experiment is disodium hydrogen phosphate citric acid with adjusted salt ion concentration of 0.5 mol/L, and the pH value is the only variable in the experiment (from 2 to 8). PAA is dissolved in deionized water (DI water) to a concentration of 5 mg/L, then used for the polymer physisorption on a silanized glass substrate, which has undergone piranha solution cleaning and then immersed in the (3-aminopropyl)- triethoxysilane (APTES) solution (2 mmol/L, CH₂Cl₂ solution) for 20 mins. After that, the sample is rinsed with abundant DI water to remove the loosely adsorbed polymer and dried by air flow. The single molecule force spectroscopy experiments were carried on a commercial atomic force microscope (Asylum Research, MFP-3D). The experimental results show that as the pH value increases, the single PAA chain undergoes from collapsed conformation to fully extended conformation, and the energy required for the transformation between different conformations during the stretching process is calculated. In addition, according to the chain shrinkage rate under different loads, the shrinkage work of single PAA chain under the change of pH is calculated. Based on the characteristic of the conformation changes of single PAA chain with pH value, a new molecular motor (switch) design concept was proposed. It can be expected that the result of this work can provide theoretical basis and data support for the design of multi response polymer and novel smart sensors.

Key words: single molecular force spectroscopy, pH-sensitive polymer, conformational change, molecular motor, molecular switch, smart sensor

引用此文

于淼, 赵武, 张凯, 郭鑫. pH敏感型智能高分子单链力学性能研究[J]. 化学学报, 2021, 79(4): 500-505.

Miao Yu, Wu Zhao, Kai Zhang, Xin Guo. Single-Molecule Mechanism of pH Sensitive Smart Polymer[J]. Acta Chimica Sinica, 2021, 79(4): 500-505.

导出引用 EndNote|Reference Manager|ProCite|BibTeX|RefWorks

分享此文

图/表 5

图1. (a) PAA在正辛基苯中的典型力-距离(F-E)曲线; (b) 归一化的(a)中的曲线

Figure 1. (a) Typical single-chain F-E curves of PAA obtained in n-octylbenzene; (b) the normalized single-chain F-E curves of those shown in (a)

图2. 归一化的PAA在正辛基苯中的F-E曲线(蓝色)以及QM-FRC在lb=0.154 nm的理论曲线(虚线)

Figure 2. Normalized single-chain F-E curves of PAA obtained in n-octylbenzene (blue line) and the QM-FRC fitting curve with lb=0.154 nm (yellow dotted line)

图3. 归一化的PAA的F-E曲线. (a) 0.5 mol/L磷酸氢二钠-柠檬酸缓冲液中, pH=2(黑色实线), pH=3(红色虚线); (b) 正辛基苯(蓝色实线), pH=3(红色虚线)

Figure 3. Normalized single-chain F-E curves of PAA chains. (a) The disodium hydrogen phosphate-citric acid buffer solution with the concentration of 0.5 mol/L. pH=2 (black line), pH=3 (red dotted line); (b) n-octylbenzene (blue line), pH=3 (red dotted line)

图4. 归一化的PAA在0.5 mol/L磷酸氢二钠-柠檬酸缓冲液的F-E曲线. (a) pH=3(红色虚线), pH=5(绿色点划线); (b) pH=5(绿色点划线), pH=8(紫色三点划线)

Figure 4. Normalized single-chain F-E curves of PAA obtained in the buffer solution with the concentration of 0.5 mol/L. (a) pH=3 (red dotted line), pH=5 (green dot dash line); (b) pH=5 (green dot dash line), pH=8 (purple three-dot dash)

图5. 归一化的PAA在0.5 mol/L磷酸氢二钠-柠檬酸缓冲液中F-E曲线. (a) pH=3(红色虚线), pH=8(紫色三点划线); (b) 基于pH敏感高分子的分子马达设计概念; (c) 基于pH敏感高分子的分子开关设计概念

Figure 5. Normalized single-chain F-E curves of PAA obtained in the buffer solution with the concentration of 0.5 mol/L: (a) pH=3 (red dotted line), pH=8 (purple three-dot dash); (b) a novel molecular motor can be proposed according to the variation of single-chain mechanics of pH sensitive polymers; (c) a novel molecular switch based on pH-sensitive polymer

参考文献 48

[1]	Stuart, M.A. C.; Huck, W.T. S.; Genzer, J.; Muller, M.; Ober, C.; Stamm, M.; Sukhorukov, G.B.; Szleifer, I.; Tsukruk, V.V.; Urban, M.; Winnik, F.; Zauscher, S.; Luzinov, I.; Minko, S. Nat. Mater. 2010, 9,101.
[2]	Schmaljohann, D. Adv. Drug Deliv. Rev. 2006, 58,1655.
[3]	Qiu, Y.; Park, K. Adv. Drug Deliv. Rev. 2001, 53,321.
[4]	Gil, E.S.; Hudson, S.M. Prog. Polym. Sci. 2004, 29,1173.
[5]	Qiu, X.Y.; Hu, S.W. Materials 2013, 6,738.
[6]	Bae, Y.; Fukushima, S.; Harada, A.; Kataoka, K. Angew. Chem.-Int. Ed. 2003, 42,4640.
[7]	Hu, W.; Zhang, Y. Acta Chim. Sinica 2010, 68,1855. (in Chinese)
	( 胡炜, 张颖, 化学学报, 2010, 68,1855.)
[8]	Lu, T.T.; Liu, J.; Li, H.; Wei, T.B.; Zhang, Y.M.; Lin, Q. Prog. Chem. 2016, 28,1541. (in Chinese)
	( 逯桃桃, 刘娟, 李辉, 魏太保, 张有明, 林奇, 化学进展, 2016, 28,1541.)
[9]	Galaev, I.Y.; Mattiasson, B. Trends Biotechnol. 1999, 17,335.
[10]	Dai, Y.N.; Li, P.; Wang, A.Q. Prog. Chem. 2007, 19,362. (in Chinese)
	( 戴亚妮, 李平, 王爱勤, 化学进展, 2007, 19,362.)
[11]	Lutz, J.F. J. Polym. Sci. Polym. Chem. 2008, 46,3459.
[12]	Hu, J.L.; Meng, H.P.; Li, G.Q.; Ibekwe, S.I. Smart Mater. Struct. 2012, 21,23.
[13]	Zhou, H.W.; Ding, X.B. Prog. Chem. 2016, 28,111. (in Chinese)
	( 周宏伟, 丁小斌, 化学进展, 2016, 28,111.)
[14]	Kim, Y.J.; Matsunaga, Y.T. J. Mater. Chem. B 2017, 5,4307.
[15]	Guan, X.L.; Li, Z.F.; Wang, L.; Liu, M.N.; Wang, K.L.; Yang, X.Q.; Li, Y.L.; Hu, L.L.; Zhao, X.L.; Lai, S.J.; Lei, Z.Q. Acta Chim. Sinica 2019, 77,1268. (in Chinese)
	( 关晓琳, 李志飞, 王林, 刘美娜, 王凯龙, 杨学琴, 李亚丽, 胡丽丽, 赵小龙, 来守军, 雷自强, 化学学报, 2019, 77,1268.)
[16]	Guan, X.L.; Wang, L.; Li, Z.F.; Liu, M.N.; Wang, K.L.; Lin, B.; Yang, X.Q.; Lai, S.J.; Lei, Z.Q. Acta Chim. Sinica 2019, 77,1036. (in Chinese)
	( 关晓琳, 王林, 李志飞, 刘美娜, 王凯龙, 林斌, 杨学琴, 来守军, 雷自强, 化学学报, 2019, 77,1036.)
[17]	Maleki, R.; Khoshoei, A.; Ghasemy, E.; Rashidi, A. J. Mol. Graph. Model. 2020, 100,107660.
[18]	Shi, Z.Q.; Li, Q.Q.; Mei, L. Chin. Chem. Lett. 2020, 31,1345.
[19]	Kanamala, M.; Wilson, W.R.; Yang, M.M.; Palmer, B.D.; Wu, Z.M. Biomaterials 2016, 85,152.
[20]	Meng, F.D.; Sun, J.; Li, Z.B. Chin. J. Chem. 2019, 37,1137.
[21]	Zhang, D.J.; Liu, J.; Chen, B.; Wang, J.X.; Jiang, L. Acta Chim. Sinica 2018, 76,425. (in Chinese)
	( 张大杰, 刘捷, 陈波, 王京霞, 江雷, 化学学报, 2018, 76,425.)
[22]	Chen, X.M.; Chen, Y.; Liu, Y. Chin. J. Chem. 2018, 36,526.
[23]	Yu, Q.L.; Li, Z.; Dou, C.Y.; Zhao, Y.P.; Gong, J.X.; Zhang, J.F. Prog. Chem. 2020, 32,179.
[24]	Miao, J.K.; Shi, Y.Y.; Zhu, H.F.; Gao, M.Y. Chin. J. Chem. 2020, 38,719.
[25]	Richter, A.; Bund, A.; Keller, M.; Arndt, K.F. Sensor. Actuat. B-Chem. 2004, 99,579.
[26]	Shaibani, P.M.; Jiang, K.R.; Haghighat, G.; Hassanpourfard, M.; Etayash, H.; Naicker, S.; Thundat, T. Sensor. Actuat. B-Chem. 2016, 226,176.
[27]	Zhang, C.J.; Cano, G.G.; Braun, P.V. Adv. Mater. 2014, 26,5678.
[28]	Scarpa, E.; Mastronardi, V.M.; Guido, F.; Algieri, L.; Qualtieri, A.; Fiammengo, R.; Rizzi, F.; De Vittorio, M. Sci. Rep. 2020, 10,10.
[29]	Li, J.Y.; Li, H.B. Nanoscale 2020, 44,22564.
[30]	Neuman, K.C.; Nagy, A. Nat. Methods 2008, 5,491.
[31]	Rief, M.; Oesterhelt, F.; Heymann, B.; Gaub, H.E. Science 1997, 275,1295.
[32]	Rief, M.; Pascual, J.; Saraste, M.; Gaub, H.E. J. Mol. Biol. 1999, 286,553.
[33]	Benoit, M.; Gabriel, D.; Gerisch, G.; Gaub, H.E. Nat. Cell Biol. 2000, 2,313.
[34]	Janshoff, A.; Neitzert, M.; Oberdorfer, Y.; Fuchs, H. Angew. Chem.-Int. Ed. 2000, 39,3213.
[35]	Kilchherr, F.; Wachauf, C.; Pelz, B.; Rief, M.; Zacharias, M.; Dietz, H. Science 2016, 353,9.
[36]	Cai, W.H.; Xu, D.; Qian, L.; Wei, J.H.; Xiao, C.; Qian, L.M.; Lu, Z.Y.; Cui, S.X. J. Am. Chem. Soc. 2019, 141,9500.
[37]	Zhang, S.; Qian, H.J.; Liu, Z.H.; Ju, H.Y.; Lu, Z.Y.; Zhang, H.M.; Chi, L.F.; Cui, S.X. Angew. Chem.-Int. Ed. 2019, 58, 1659.
[38]	Cui, S.X. Acta Polym. Sin. 2016,1160. (in Chinese)
	( 崔树勋, 高分子学报, 2016,1160.)
[39]	Li, H.B.; Liu, B.B.; Zhang, X.; Gao, C.X.; Shen, J.C.; Zou, G.T. Langmuir 1999, 15,2120.
[40]	Luo, Z.L.; Zhang, B.; Qian, H.J.; Lu, Z.Y.; Cui, S.X. Nanoscale 2016, 8,17820.
[41]	Bao, Y.; Luo, Z.L.; Cui, S.X. Chem. Soc. Rev. 2020, 49,2799.
[42]	Zhang, Y.-H.; Wang, Z.-Q.; Zhang, X. Acta Polym. Sin. 2009,973. (in Chinese)
	( 张义恒, 王治强, 张希, 高分子学报, 2009,973.)
[43]	Zhang, W.-K.; Wang, C.; Zhang, X. Chinese Sci. Bull. 2003, 48,1113. (in Chinese)
	( 张文科, 王驰, 张希, 科学通报, 2003, 48,1113.)
[44]	Yang, J.; Petitjean, S.J. L.; Koehler, M.; Zhang, Q.; Dumitru, A.C.; Chen, W.; Derclaye, S.; Vincent, S.P.; Soumillion, P.; Alsteens, D. Nat. Commun. 2020, 11,4541.
[45]	Yu, M.; Qian, L.; Cui, S.X. J. Phys. Chem. B 2017, 121,4257.
[46]	Wang, K.F.; Pang, X.C.; Cui, S.X. Langmuir 2013, 29,4315.
[47]	Oesterhelt, F.; Rief, M.; Gaub, H.E. New J. Phys. 1999, 1,11.
[48]	Cai, W.H.; Xiao, C.; Qian, L.M.; Cui, S.X. Nano Res. 2019, 12,57.