Preparation And Application Of Functional Nanomaterials

Cancer is a group of diseases associated with abnormal growth of cells,which has posed a great threat to people’s health.The development of imaging methods as well as photoacoustic and photothermal treatments based on functional nanomaterials is of high significance to improve cancer diagnosis and treatment.Apart from cancer therapy,the early diagnosis of cancer,especially the classification of tumor cells,is crucial to improve the early tumor detection rate and tumor prognosis.Traditional methods for detection and analysis of cells are usually by means of collecting the average signals of population cells.Since the morphology,volume and protein expression etc.vary significantly between cells,the analysis of population cells cannot reveal the heterogeneity and obtain accurate information of cancer cells.Furthermore,under the proposal of“carbon peak and neutrality targets”,electrocatalytic CO₂ reduction reaction（CO₂RR）,due to its ability to convert CO₂into value-added chemicals,has become a very hot topic in the field of chemistry.Due to the variety of products generated by CO₂ reduction reaction（CO₂RR）,improving the selectivity of the value-added chemicals,such as multicarbon hydrocarbons,is of high significance yet remains a great challenge.Focusing on the functional nanoparticles（NPs）,a simple method for prepare multi-functional nanoagent is developed and the efficacy of population NPs on cancer treatment is investigated.In view of the fact that collecting the signals of population NPs cannot reveal the heterogeneity of individual NPs,single entity impact electrochemistry based on single nanoparticle impact electrochemistry（NIE）is developed and used to the detection of single cancer cells.Besides,the concept of fluidized electrochemistry based on NIE is proposed and used to improve the CO₂RR activity,promoting NIE technique to the application stage.Main research work in this thesis includes:（1）One-step reduction-encapsulated method has been developed for synthesize multicore-shell polydopamine-coated Ag nanoparticles（AgNPs@PDA）as a cancer theranostic agent,integrating amplified photoacoustic imaging,enhanced photothermal therapy,and photothermal promoted dual tumor microenvironment-coactivated chemodynamic therapy.The photoacoustic signal and the photothermal conversion efficiency of AgNPs@PDA nanosystem present a 6.6-and 4.2-fold enhancement compared to those of M-AgNPs-PDA（simply mixing PDA and AgNPs）derived from the increased interface heat transfer coefficient and the stronger near-infrared absorption.Moreover,AgNPs@PDA coactivated by dual tumor microenvironment enables controllable release of hydroxyl radicals（·OH）and toxic Ag⁺,which can be further promoted by near-infrared light irradiation.Importantly,the high efficiency of AgNPs@PDA nanosystem with prominent photoacoustic imaging-guided synergistic photothermal-chemodynamic cancer treatment is also found in in vitro and in vivo studies.Besides,the formation mechanism of the one-step synthesized multicore-shell nanomaterials is systematically investigated.This work provides a much simplified one-step synthesis method for the construction of a versatile nanoplatform for cancer theranostics with high efficacy.（2）Fast,simple,and specific detection and analysis of single cancer cells has been realized by combining single entity impact electrochemistry and microfluidic technology.MCF-7 tumor cells are specifically labelled with AgNPs,which can be easily oxidized under specific potentials to serve as the electrochemical labels when single MCF-7 tumor cells impact on the microelectrode.This study provides methodological and technical support for the early cancer detection,pathological analysis,and the investigation of physiological and biochemical processes at a single cell level.（3）The strategy of fluidized CO₂ RR based on fluidized electrochemistry for modulating reaction selectivity has been established.Compared to a fixed reaction mode,the faradic efficiency（FE）of C₂H₄ and HCOOH originated from CO₂RR catalyzed by Au Cu₂/C with fluidized mode exhibit a 9.2-and 2.5-fold enhancement,respectively.Meanwhile,the FE of CO and the by-product H₂ decrease noticeably.These results reveal that fluidized electrochemi stry can improve selectivity of the high-value products.More importantly,the corresponding mechanism of the significantly altered selectivity is systematically studied and elucidated,which can be attributed to the enhanced mass transport,reduced reacti on time scale and intermittent reaction mode of the fluidized electrochemistry.This work provides a simple and effective strategy for regulating the product selectivity of CO₂ RR.