The Design Of Fluorescence Sensing Systems Based Nanomaterials For The Detection Of L-Histidine

The small biological molecules,amino acids,play an important part in the development and metabolic activities of the human body.Histidine is one of the basic amino acids.The abnormal content of histidine in body fluids is related to various diseases,such as epilepsy,Parkinsonism,histidinemia etc.Therefore,the development of a rapid,simple,and reliable histidine detection method is of great significance for human health and early disease diagnosis.Among the many existing analysis methods,fluorescent detection based on nanomaterials have superiority in the respect of short response time,simple operation,low cost,etc.And it can realize timely,accurate and highly sensitive detection of histidine.In this study,three kinds of nanomaterials with excellent optical properties were used,nitrogen-doped carbon quantum dots（N-CDs、Y-CDs）and gold nanoclusters（Au NCs）.Firstly,blue fluorescent nitrogen-doped carbon quantum dots（N-CDs）were obtained by pyrolysis,then curcumin-modified gold nanoclusters（CCM-Au NCs）were synthesized,and then yellow fluorescent carbon quantum dots（Y-CDs）were obtained by one pot hydrothermal method.Secondly,the morphology,surface state,element composition and optical properties of the synthesized nanomaterials are characterized by TEM,XPS,FT-IR and UV-vis.And the optical performance of the constructed sensor for histidine detection was investigated by fluorescence analysis.Finally,the constructed fluorescent sensor was applied to the detection and research of histidine.The specific research contents are as follows:（1）Using guanosine as the carbon source and histamine as the nitrogen source,blue light nitrogen-doped carbon quantum dots（N-CDs）with good dispersion and high quantum yield were synthesized by high temperature pyrolysis.Based on the photoinduced electron transfer effect（PET）,an N-CDs-Cu²⁺sensor was constructed to quantitatively analyze and detect histidine,and the effects of Cu²⁺concentration,p H,temperature,and His-Cu²⁺response time on sensor performance were explored.The linear range of the sensor for detecting histidine was 0～50μM,and the theoretical detection limit is calculated to be 1.37μM under the best experimental conditions.Moreover,the N-CDs-Cu²⁺sensor had good selectivity and reliability for the detection of histidine（RSD<5%）,and has a good recovery rate（100.12%～103.80%）in the detection of serum samples.It indicates that this method has the potential for actual detection.（2）Using bovine serum albumin as a reducing agent,red fluorescent gold nanoclusters（CCM-Au NCs）modified with curcumin（CCM）were successfully prepared.The CCM-Au NCs-Ni²⁺fluorescence sensor was constructed based on the PET effect,which could realize the sensitive detection of histidine.The experimental results displayed that the linear range of the constructed CCM-Au NCs-Ni²⁺sensor for histidine detectionis 5～80μM（R²=0.9918）,and the theoretical detection limit is 0.81μM（S/N=3）.In addition,the CCM-Au NCs-Ni²⁺sensor has good selectivity and high precision in the histidine detection process（RSD<5%）,and has a good recovery rate in the detection of serum samples（98.76%～101.63%）,providing a new detection method for the detection of histidine in actual human serum samples.（3）Nitrogen-doped yellow-light carbon quantum dots（Y-CDs）and N,N-bis（carboxymethyl）-lysine（BCML）modified gold nanoparticles（BCML-Au NPs）were prepared.Based on the principle of internal filtering effect（IFE）,Y-CDs/BCML-Au NPs fluorescence sensors was constructed to realize fast and sensitive detection of histidine.Under the best conditions,the linear range of the constructed Y-CDs/BCML-Au NPs fluorescence sensor for L-His detection is 0～18μM（R²=0.9960）,and the theoretical detection limit is 0.093μM（S/N=3）.In addition,the Y-CDs/BCML-Au NPs fluorescent sensor had strong anti-interference ability and good stability.It had achieved good detection results in the spiked recovery experiment of human serum samples.This method of histidine detection in human serum samples has potential application value.