Conjugate Structure Regulation Of Xylose Carbon Dots And Its Application

Carbon dots(CDs)are favored by researchers because of their excellent biocompatibility,optical properties and high stability.With the continuous enrichment of preparation methods and the progress of characterization methods,the application of CDs in production and life is also increasing.Up to now,the structure of CDs is not clear,which has limited the application of CDs.It is particularly meaningful to adjust the structure of the existing CDs to improve its performance.In this paper,we propose to control the effective conjugate area of CDs,study the feasibility of this method in the control of CDs structure,and explore the influence of the change of reaction conditions on the properties of CDs during the preparation process.On this basis,CDs regulated by structure are applied to promote photosynthesis and enhance microbial electricity production,and the promotion mechanism is revealed.Four kinds of CDs dots with different fluorescence emission behaviors were synthesized by a simple one-step hydrothermal method using natural bio-based non-aromatic xylose as the carbon source.Transmission electron microscopy showed that the CDs obtained were quasispherical and highly dispersed,and had obvious lattice structure.Through fluorescence spectrum test,it is confirmed that the four carbon points have obvious CDs excitation dependence.The emission spectrum corresponding to its maximum excitation wavelength can be calculated by CIE to show that it has blue,green,yellow and orange fluorescence emission respectively.X-ray photoelectron spectroscopy confirmed that the four CDs contained only carbon and oxygen.By combining the results of Raman spectroscopy and X-ray photoelectron spectroscopy,it is revealed that the reason for the gradual redshift of the fluorescence emission peaks of the four CDs is the extension of the effective conjugation area.On the basis of the above results,the reaction temperature of the orange light CDs prepared by the above methods was adjusted.Under the same reaction conditions,adjust the reaction temperature to 140 ℃,160 ℃,180 ℃ and 200 ℃ respectively.The obtained CDs have uniform particle size and obvious lattice structure.The fluorescence emission spectrum did not show obvious changes during the gradual increase of reaction temperature.They were applied to the Hill reaction of chloroplast,and the following rules were found: The higher the reaction temperature for preparing CDs,the faster the Hill reaction rate.Among them,the experimental group with the greatest improvement in Hill reaction efficiency showed about 1.6times improvement compared with the control group.Through the characterization of adenosine triphosphate and electron transfer rate in the system,it was confirmed that the addition of CDs had a significant improvement on it.The photocurrent test proved that the addition of CDs can effectively increase the photocurrent production of chloroplasts,and the electrochemical impedance test shows that the higher the reaction temperature,the better the electron transmission ability.Combined with the results of Raman spectroscopy and X-ray photoelectron spectroscopy,it is revealed that the higher the hydrothermal reaction temperature,the more conducive to the extension of the effective conjugation area.In the synthesis and preparation of CDs,heteroatom doping can effectively improve the performance of CDs.Based on the above theory,heteroatoms are further introduced into the preparation of CDs.Two kinds of CDs with different effective conjugated domain areas were constructed by introducing fatty diamine and aromatic diamine respectively and they were used to promote the electricity production of Shewanella.In the process of co-culture of the above two CDs with Shewanella at different concentrations,Shivanella did not show significant side effects such as growth inhibition or growth promotion,which proves that the two CDs have good biocompatibility.Co-culture of CDs and Shewanella can effectively enhance the current output of Shewanella,which is 1.9 times and 3.9 times higher than that of control group,respectively.The section electron microscope technology strongly proves that CDs can be effectively absorbed into the body by bacteria and widely exist in the cytoplasm.It was proved by electrochemical characterization that the addition of aromatic diamine effectively improved the electronic transmission capacity of CDs,and significantly improved the electronic transmission capacity of Shewanella.Through the comparison of the structure of the above two CDs and the confirmation of the relevant characterization results,it is once again confirmed that the increase of the effective conjugation area is conducive to the transmission of electrons.