Design And Synthesis Of Nano-artificial Antibody And Its Application In Early Diagnosis Of Myocardial Infarction And Heart Failure

Myocardial infarction and heart failure are the most common cardiovascular and cerebrovascular diseases.In order to reduce the incidence,the early diagnosis of myocardial infarction and heart failure is particularly important.At present,the diagnosis of myocardial infarction and heart failure is mainly based on electrocardiogram and biomarker detection kits.The former requires professional detection equipment or personnel,and the latter is an immunoassay based on monoclonal antibodies,which is limited by the high cost of protein antibodies.The screening cycle is long and has shortcomings such as immunogenicity,so it has great limitations in practical applications.Based on this,this thesis synthesized a new type of nano artificial antibody based on the biomimetic molecular design method,which has good affinity and selectivity for myocardial infarction and heart failure markers,and can selectively identify and capture myocardial infarction and heart failure from serum samples.Combined with fluorescent carbon quantum dots,fluorescent test strips were prepared to realize the visual detection of biomarkers in serum samples;Fluorescent detection kits were prepared to realize the quantitative detection of serum markers in a short time.The research results of this paper are as follows:(1)The rational construction and synthesis of nano-artificial antibodies.Taking myocardial infarction biomarker cardiac troponin Ⅰ(cTnI)and heart failure marker human brain natriuretic peptide(BNP)as the research objectives,by optimizing the screening of functional monomer ratio and formula,the synthesis of cTnI and BNP has a high-affinity nano-artificial antibody;the affinity constant KD of nano-artificial antibody for cTnI is 2.02×10-9 M,which is equivalent to protein antibody;in order to further improve the selectivity of nano-artificial antibody,the epitope polypeptide of cTnI is used as template,using molecular imprinting technology to introduce selective recognition sites,the affinity constant KD value of nano artificial antibody for cTnI is 8.57×10-10 M,and the affinity constant KD value for BNP is 1.41 × 10-11 M,and it has a good selectivity.(2)Preparation of nano artificial antibody fluorescent test strips and visual detection of biomarkers.The blue and red fluorescent carbon quantum dots were synthesized by hydrothermal method.The blue fluorescent carbon quantum dots(B-CD)were coated inside the artificial nano-antibody to form fluorescent nano-artificial antibodies.The red fluorescent carbon quantum dots(R-CD)coated inside silica nanoparticles,the two types of nanoparticles are mixed according to a volume ratio of 3:1,and then suction filtered on a nitrocellulose membrane to prepare a nano artificial antibody fluorescent test strip.The fluorescence change on the surface of the fluorescent test strip can visually detect BNP and cTnI in serum samples within 5 minutes.(3)Fluorescence kits are prepared based on nano artificial antibodies for quantitative detection of BNP.Based on the visual detection results of fluorescent test strips,the fluorescent nano-artificial antibody and fluorescent silica were mixed in a 96-well plate at a volume ratio of 1:1,and the fluorescence intensity before and after adding the serum was measured with a microplate reader.According to the change of fluorescence intensity,the quantitative detection of BNP in serum samples is realized,and the relative standard deviation RSD of the same concentration of serum samples and different batches for 10 repeated tests is 7.3%;the relative standard deviation RSD of the same serum sample for 10 times repeated tests is 2.33%,and the minimum detection limit of this method is 2 pg/mL.