| The lateral flow immunochromatographic biosensor is a paper-based platform biosensor.As a diagnostic device,it is widely used in food safety,medical diagnosis,environmental health and other fields because of its high sensitivity,specificity,rapid,low cost and user-friendly characteristics.Most of the immunochromatographic strips rely on the color signals on the test line to determine the results.Micro-or nano-particles with various colors are usually used as a label in immunochromatographic strips.Gold nanoparticles(AuNPs)is popular with its good biocompatibility and can change their surface plasmon resonance absorption peaks by adjusting their morphology or size,thereby adjusting the color of colloidal solution.So AuNPs has good a value in application of lateral flow immunochromatographic biosensor.Enzyme-linked immunosorbent assay(ELISA)is a commonly used immunochromatographic strip method to detect the target by specific binding of antigen and antibody,but the cost of antibody is high and it is difficult to store.In contrast,nucleic acid probes are inexpensive,easy to synthesize and be modified,small in size and good in stability,so they have gradually become substitutes for antibodies and have been applied in biological analysis in recent years.In addition,during the period of human body is infected with virus,it takes several weeks for the human body produces antibodies in response to the virus,so the detection of disease genes is more conducive to the early diagnosis and treatment of disease.The main significance of these researchs are combining the AuNPs with nucleic acid probes to detect related disease genes,and provide new ideas for the application of DNA functionalized AuNPs.The research content of this paper has the following points:(1)A fast,low-cost lateral flow nucleic acid biosensor was introduced to detect the hepatitis B virus DNA.The principle of this method is based on the nucleic acid hybridization reaction.Considering that traditional DNA modification of gold nanoparticles takes a long time,this experiment combined the thiol-modified DNA rapidly on the surface of the gold nanoparticles by freeze-thaw method.The mixure was then washed and added to the test strip sensor together with the target.After the solution flows laterally through the entire detection area,the AuNPs will gradually accumulate on the test line,produce a visible color band,and then use the instrument to measure the signal intensity on the test line of the given area as the basis for quantitative analysis.The response of the method to the target DNA ranged from 0.5 to 50 n M with a detection limit of 0.46 n M.This method is a potentially valuable tool for clinical applications and biomedical diagnostics,especially in limited resource environments.(2)A rapid,simple and visual lateral flow biosensor(LFB)based on gold nanostars(AuNSs)has been established for the detection of Human immunodeficiency virus DNA.In this protocol,the AuNSs as a color label for visual detection was synthetized by an environmental friendly chemical method.The “sandwich structure” was applied in the measurement principle: the target was captured by the DNA-modified AuNSs and then trapped on the test line by the principle of complementary base pairing.Afterwards,the change of the color on test line can be visually detected for qualitative analysis and using a portable strip reader that records the color intensity of the band can achieve quantitative analysis.Under optimum conditions,this AuNSs-based LFB strategy exhibited a good linear relationship range of 0.2-50 n M with the limit of detection of 0.14 n M.Moreover,this LFB shows good anti-interference ability in the detection of human serum,which means it has the great potential in early diagnosis and treatment. |
PDF Full Text Request