Research group of Professor Lu Xiong of Southwest Jiaotong University: using two-dimensional conductive PEDOT nano sheet with redox activity of mussel like to construct bioadhesive flexible electron

The introduction of adhesive hydrogels constructed by mussel inspired polyphenol chemistry has attracted the attention of researchers because of their strong adhesion properties Mussels secrete adhesion proteins to achieve super adhesion on various surfaces, but in seawater, the adhesion groups (phenolic hydroxyl) on these proteins are easily oxidized to quinone group and lose viscosity In order to maintain the ability of long-term adhesion, mussels secrete proteins with reducing activity to maintain the dynamic balance of quinone and phenolic hydroxyl groups on adhesion proteins In recent years, Lu Xiong research group of Southwest Jiao Tong University has developed many kinds of multifunctional hydrogels which can be repeatedly adhered on the basis of mussel polyphenol chemistry, including the control of phenolquinone based oxidative balance (ACS Nano 2017, 11, 2561) based on the nano confinement domain, and the phenol quinone based oxidative balance of polyphenols in the electron transfer supported hydrogel network (Nature communications, 2019) , 10 , 1487 ； Adv Funct Mater 2019 , 1907678 ）。 Prof Lu Xiong graduated from Hong Kong University of science and technology in 2004 with a doctor's degree He is now working in the Department of Biomedical Engineering, School of materials, Southwest Jiaotong University He has successively been selected into the New Century Excellent Talents funding program (2010) of the Ministry of education, the outstanding young academic and technical leaders funding program (2011) of Sichuan Province, and the postdoctoral researcher of Japan Association for academic Revitalization (JSPS follow, 2011-2013) He has successively presided over many projects, such as the National Natural Science Foundation, the national key research and development program, 863 sub projects, the new century talent fund of the Ministry of education, Sichuan Provincial Outstanding Youth Fund, etc Professor Lu Xiong is mainly engaged in the research of biomaterials genetic engineering, biomaterial simulation and biomedical functional polymer gel design and preparation More than 160 SCI papers were published in famous international academic journals In recent years, Professor Lu Xiong's research group has made a series of progress in the design and preparation of new biomaterials, and the research results have been successively published in the journals with international influence, such as n-feature-c communications, acs-nan-o, a advanced functional m-materials, S-Mall, and C economy of m-materials Cutting edge scientific research achievements: using two-dimensional conductive PEDOT nanoflakes with redox activity of mussels to build a bioadhesive flexible electronic Figure 1 Building two-dimensional conductive polymer PEDOT nanoflakes with graphene oxide template (source: Advanced Functional M materials) graphene oxide (go) It is a kind of 2D nano sheet with large specific surface area and rich functional groups (such as hydroxyl, epoxy, carboxyl), which is usually used as a template for self-assembly of inorganic materials However, there are some difficulties in the preparation of conducting polymer PEDOT nanofilms with go as template Firstly, because the π - conjugated thiophene ring in the oxidation state of PEDOT is positively charged, it needs to be doped with a negative electric group to balance the charge Therefore, it is necessary to modify go with proper functional group to act as the dopant of PEDOT Secondly, the interaction between the functional groups of go and PEDOT is not enough to induce the assembly of PEDOT on the surface of go In order to overcome these problems, Professor Lu Xiong's research group used two steps to functionalize go: 1) to introduce sulfonic acid group on the surface of go as the doping group of PEDOT to prepare sulfonated graphene oxide (SGO); 2) to modify SGO through PDA functionalization, to introduce phenolic hydroxyl into SGO to form PSGO and enhance the interaction with PEDOT At the same time, PDA can partly reduce graphene oxide and increase the conductivity of psgo-pedot Therefore, PEDOT can be assembled on PSGO template to form conductive two-dimensional nano sheet with sandwich structure It is important that PSGO templated PEDOT (psgo-pedot) nanocomposites have abundant hydrophilic and reductive phenolic hydroxyl groups, so they will show good water dispersion and redox activity The PSGO-PEDOT nanosheets, which contain a large amount of phenolic hydroxyl groups, can be used as a general filler to prepare super stretched, conductive and adhesive hydrogels, and are applied in bioelectronics and other fields Figure 2 Performance characterization of psgo-peodt nanocomposites (source: Advanced Functional M materials) with sandwich like structure Because of the large amount of phenolic hydroxyl in the nano tablet, it can disperse uniformly in aqueous solution for a long time, and has a large solid solubility In addition, the nanocomposite also has good redox activity, the conductivity can reach 829.7 s / m, and its elastic modulus is about 11 GPa Fig 3 adhesion properties of PSGO-PEDOT-PAM hydrogels (source: Advanced F unctional M aterials) PSGO-PEDOT nanosheets can give good adhesion to hydrogels, and can be adhered to different surfaces, such as ceramics, metals, plastics, fresh pericarp, fresh tissues, etc In addition, because of the dynamic redox balance formed by phenolic hydroxyl / quinone group in PSGO-PEODT nanosheets, it can endow the hydrogel with durable and repeatable adhesive properties Fig 4 the mechanical properties of PSGO-PEDOT-PAM hydrogel (source: Advanced F unctional M aterials) PSGO-PEDOT-PAM hydrogel has better mechanical properties than PSGO-PAM hydrogel Because graphene contains large surface area and relatively abundant functional groups, it can enhance the mechanical properties of hydrogels through physical binding This study found that PSGO-PEDOT nanosheets were more conducive to improving the mechanical strength of hydrogels The reasons for their excellent enhancement effect on hydrogels were: first, PSGO-PEDOT nanosheets had stronger elastic modulus than GO; secondly, PSGO-PEDOT nanosheets contained more abundant hydrophilic groups to ensure that they were more stable Dispersing in hydrogel matrix can enhance the effect of hydrogels Secondly, PSGO-PEDOT nanosheets can form non covalent interactions with PAM chains and play a role of energy dissipation, which further improves the mechanical properties of hydrogels Fig 5 conductivity and application of PSGO-PEDOT-PAM hydrogel (source: Advanced F unctional M aterials) PSGO-PEDOT nanoscale can be well dispersed in hydrogel matrix, giving hydrogel excellent conductivity The conductive hydrogel can be used as an electronic skin, biosensor, biological electrode and so on to measure the physiological signals of the human body In addition, the hydrogel has good biocompatibility in the presence of phenolic hydroxyl groups in PSGO-PEDOT-PAM hydrogel, and can be used as an implanted electrode to measure the EEG signals of animal during beating and chewing PSGO-PEDOT nanosheets can be well dispersed in the hydrogel network due to their good water dispersibility, giving hydrogels good electrical conductivity, super mechanical properties, adhesion and biocompatibility PSGO-PEDOT nanosheets significantly improve the mechanical properties of hydrogels, which is attributed to the mechanical strength of nanoscale itself and the synergistic effect of non covalent interactions between nanosheets and polymer chain networks Nanosheets have a dynamic redox balance of phenolic hydroxyl / quinone groups, which helps to achieve repeatable and long-term adhesiveness of hydrogels Hydrophilic conductive nanosheets are well dispersed in hydrogels, forming a well connected electronic pathway in the hydrogel network and giving them good electrical conductivity PSGO-PEDOT-PAM hydrogel has excellent conductivity and adhesion It has been successfully used as a sticky electronic skin for detecting ECG, EEG and EMG signals PSGO-PEDOT-PAM hydrogel shows good biocompatibility and can be used as an implantable bioelectrode for biological signal detection in vivo In short, PSGO-PEDOT-PAM hydrogel as a highly sensitive biosensor has great potential and can be used in artificial intelligence, human-machine interaction, wearable personal medical devices and implantable bio electronics The research results were published online in advanced functional M materials (DOI: 10.1002 / ADFM 201907678) under the title of "graphene oxide templated conductive and redox active nanosheets incorporated hydraulics for advanced bioelectronics" The first author of the thesis is Gan Donglin, a doctoral student, and Huang Ziqiang, a master student The corresponding authors of the thesis are Professor Lu Xiong and associate professor Xie chaoming The research was supported by national key R & D plan, National Natural Science Foundation of China, and R & D plan of key areas in Guangdong Province 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 website, chembeangoapp, chembeango official micro blog, CBG information wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the representative research groups in China, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.