Team of academician Tian He and Professor Qu Dahui of Huali: molecular actuator with muscle like retractable driving nanoparticles

Introduction: the artificial molecular machine won the Nobel Prize in chemistry in 2016 It refers to the molecular scale machine created by chemists through organic synthesis In recent years, how to realize the functional material of molecular machine has become a hot issue in the international research As the first independent research team in the field of molecular machinery in China, Tian He, academician of School of chemistry and molecular engineering, East China University of science and technology, and Professor Qu Dahui's research team have carried out a series of pioneering work with international influence around "functional organic molecular machinery" since 2004 Recently, Tian He, academician of East China University of science and technology, and Professor Qu Dahui's research team made another breakthrough They successfully constructed a molecular actuator with a length of only a few nanometers, which can stretch and move like a muscle, and used it as a connecting unit to drive the mechanical movement of two nanometers For the first time, they realized the functional application of rotaxane molecular muscle in the micro nano world (Figure 1) The research results were published online on Chem, a sister Journal of chemistry in the world's top academic journal Cell (DOI: 10.1016 / j.champ 2018.08.030), with the title of "muscle like artistic molecular actuators for nanoparticles" Fig 1 Introduction to Tian He, academician of nano scale artificial molecular muscle actuator (source: Chem), fine chemical expert, Professor of School of chemistry and molecular engineering, East China University of science and technology, academician of Chinese Academy of Sciences, and academician of developing country academy of Sciences (Twas) Academician Tian He is mainly engaged in the basic and Application Research of fine chemicals, especially functional dyes, and widely involves organic photoelectric function, molecular machine and supramolecular polymer system Academician Tian He has published more than 550 papers in the mainstream journals in the field of international chemistry and materials, and obtained more than 70 Chinese invention patents He has cited more than 27400 times in SCI, with an H index of 92 From 2014 to 2017, Professor Tian He was a highly cited international scholar in the field of chemistry, "highly cited researchers" (Thomson Reuters web of Science) Introduction to Professor Qu Dahui, Professor of School of chemistry and molecular engineering, East China University of science and technology In 2006, he graduated from the school of chemistry and molecular engineering of East China University of science and technology with a Ph.D from academician Tian He and won 100 national excellent articles Later, he joined the research group of Professor Ben L Feringa, Nobel chemist winner of Groningen University in the Netherlands, and engaged in post doctoral research After returning to China in 2009, a research group was established to study organic functional molecular machines and supramolecular chemistry In the past five years, he has published more than 40 SCI papers in Chem Rev., scienceadvances, chem, angel Chem Int ed., adv mater., chem SCI., org Lett., chem Commun., and other world-class magazines as the first / corresponding author He cited more than 2000 times for all articles Advanced scientific research results: nano scale artificial molecular muscle actuator the muscle fiber in the moving object is a kind of biomolecular machine that can produce relaxation / contraction motion by consuming chemical energy, and undertakes the important task of converting chemical energy into mechanical energy In order to simulate the function of this important biomolecular machine, synthetic chemists try to build an artificial molecular muscle with reversible relaxation contraction function in the laboratory by organic synthesis method At present, the international research focuses on the use of covalent, supramolecular polymerization methods to achieve the cluster amplification effect of molecular muscle, so that the molecular level movement can be amplified to the macro scale, and then to perform some functions similar to the stimulus response actuator However, because the size of molecular muscle is very small, it seems to be a very reasonable idea to use this kind of nano level muscle to regulate the micro objects at nano scale However, there are still many research challenges to realize this idea: for example, how to overcome the intrinsic thermodynamic noise of single molecular muscle, how to realize the efficient connection between molecular muscle and nano objects, how to characterize the reversible activation of molecular muscle at this molecular scale, and whether these molecular machines can still move efficiently and reversibly on the surface phase like the solution phase Based on the previous research on surface supramolecular chemistry (angelw Chem Int ed 2015, 54, 15789; adv mater 2017, 29, 1604948) and mechanical interlocking molecules (chem SCI 2016, 7, 1696; chem SCI 2017, 8, 6777), the research team successfully synthesized a linear molecular muscle with complex interpenetrating daisy chain structure (Figure 2) This kind of molecular muscle can produce reversible stretching movement under the stimulation of acid and alkali The stimulus response is based on the controlled movement of the [C2] daisy chain of the crown ether ring between two recognition sites In the initial state, the binding force of crown ether ring to the recognition site of benzylalkylammonium salt (blue site) is strong, so the molecule is in a "Relaxation" state; then the ammonium salt site is deprotonated by adding alkali, and the crown ether ring loses the strong binding force of the original and the ammonium salt site, so it slides to the second recognition site of methyltriazole unit, making the whole molecule "shrink" linearly, with length It also changes At the same time, in order to drive the molecular stretching movement to the nanoparticles, the researchers covalently modified six mercaptan groups on both ends of the molecular muscles By forming a stable gold sulfur bond with the gold nanoparticles, the molecular muscles can be efficiently connected with the two gold nanoparticles to realize the assembly and fixation of the molecular machines on the surface of the nanoparticles Fig 2 Structural formula and stretching mechanism of molecular muscle (source: Chem) However, if the molecular muscle of this polythiol group is directly added to the gold nanoparticle solution as a connecting unit, it is very easy to form a nanoparticle polymer, and the degree of aggregation is uncontrollable In order to overcome the disadvantage that the solution phase is easy to form nano polymer, the researchers used the strong physical adsorption of the glass surface on the gold nano particles, and adopted the strategy of gradual modification on the surface of the glass substrate (Fig 3, a and b) With the help of the single particle photoelectric analysis platform (chem SOC Rev 2012, 41, 632) developed by Professor Long Yitao of the school of chemistry and molecular engineering of East China University of science and technology, the researchers have successfully achieved the optical signal output of the reversible movement of molecular muscles at the single particle scale (Fig 3, C and D) At the single particle scale, the optical signal of a single nano dimer can reach about 6 nm displacement before and after driving, and this reversible wavelength displacement can be driven at least four times in situ at the single particle scale Combined with a series of control experiments and theoretical simulation results, the researchers have proved that the observed optical signal really comes from the reversible stretching of molecular muscle This result is not only the first time to collect the optical signal of molecular muscle movement at the level of single particle, but also more importantly, because the optical signal can be integrated in time dimension, it can effectively overcome the single molecular thermodynamic noise of molecular muscle and solve the long-term problem of single molecular thermodynamic noise of molecular muscle under the condition of non cluster It provides an important solution for the signal output and functional device of rotaxane molecular machine at the single molecular scale Figure 3 Schematic diagram of immobilization of molecular muscle actuator (a, b) and single particle optical signal change monitoring (C, d) of nano dimer before and after molecular muscle stretching (source: Chem) The research results are published in chem (DOI: 10.1016 / j.chempr 2018.08.030) The first authors of this paper are Dr Zhang Qi and Dr Rao Sijia, doctoral students, and the corresponding authors are academician Tian He and Professor Qu Dahui This work has been carefully guided by Professor Long Yitao and associate researcher Li Dawei of the school of chemistry and molecular engineering of East China University of science and technology in the dark field microscope test, and also greatly assisted by Professor Chen Na in the finite element simulation in the Key Laboratory of special optical fiber and optical access network of Shanghai University The research work was supported by NSFC's innovative groups, major projects and "111 talent introduction plan" Review of previous reports: academician Tian He and Professor Long Yitao of East China University of science and technology research team: single particle photoelectrochemistry on the interface of titanium dioxide film functionalized ultramicroelectrode Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeangoapp, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.