8-hydroxy-2'-deoxyguanosine (8-OHdG) is a sensitive and stable biomarker for evaluating DNA oxidative damage. A rapid and sensitive colloidal gold immunochromatographic strip was developed for 8-OHdG detection by a competitive method. The sample pad (glass cellulose film), bonding pad (glass cellulose film), nitrocellulose film and absorbent pad were pasted on the polyvinyl chloride (PVC) base plate to construct the test strip. Colloidal gold (AuNPs) was prepared by the reduction of chloroauric acid with sodium citrate. 8-OHdG antibody (Ab) was coated on the outer layer of AuNPs to form Ab@AuNPs as a probe. Bovine serum albumin (BSA) and 8-OHdG were conjugated with carbodiimide hydrochloride to prepare an artificial antigen, which was used as the coating antigen of detection line. Goat anti mouse polyclonal antibody IgG was used as the coating antibody of control line. The experimental parameters were optimized including the type of nitrocellulose membrane, the formula of loading solution, and the spraying amount of gold labeled antibody. The results showed that the appropriate nitrocellulose membrane was CN 95. The optimal loading solution included BSA (1%), Tween-20 (3%), sucrose (3%) and NaCl (0.9%). The optimal spraying amount of gold labeled antibody was 4 μL. 8-OHdG can be detected by the strip under visible light, and the level of 8-OHdG in urine can be preliminarily determined by comparing the color intensity of T line and C line. The 8-OHdG concentration in urine was further calculated by the gray value of T line and the threshold of detection was 2.55 μg/L. This colloidal gold immunochromatographic strip is simple, rapid and specific for detecting 8-OHdG in human urine to preliminarily evaluate the human status.
8-Hydroxy-2'-Deoxyguanosine ; Animals ; Antibodies, Monoclonal ; Gold ; Gold Colloid/chemistry* ; Metal Nanoparticles ; Mice ; Sensitivity and Specificity

Colloidal gold immunochromatographic strip is a fast, sensitive and accurate solid-phase labeling detection technology, which has the advantages of low price, easy operation, rapid detection and high specificity, with the potential to qualitatively detect the relevant viruses in a short time with desired sensitivity and accuracy. It effectively addresses the disadvantages of long detection time, equipment inconvenience and professionalism requirement of the traditional detection methods used in the medical, veterinary, animal, plant virus detection, pesticide residue detection and other areas. Presently, the technology has been applied in the detection of bacterial diseases, viral diseases and prevention of extensive spread of infectious diseases, and has sufficient room for further development. This review summarizes the application of colloidal gold immunochromatography strip for biological virus detection, followed by prospecting future perspectives.
Animals ; Antibodies, Monoclonal/chemistry* ; Chromatography, Affinity ; Gold Colloid/chemistry* ; Pesticide Residues ; Sensitivity and Specificity

OBJECTIVETo compare the sensitivity, the specificity and the anti-jamming of several excrement occult blood experimental techniques. To evaluate the effect of transferrin (Tf) in the excrement in the digestive tract hemorrhage detection rate.

METHODSFor 600 patients of clinical suspicious digestive tract hemorrhage, take their excrement specimen, using the chemical process (pyramidon semi-quantitative examination law) to detect hemoglobin (Hb), and using monoclonal antibody colloidal gold method to detect Hb and Tf.

RESULTSFinally the hemoglobin chemical process (hereafter refers to as chemical process) to detect upper gastrointestinal hemorrhage with the positive rate 57.3%, and the detection of hemorrhage of lower digestive tract's positive rate is 44.8%; Hemoglobin monoclonal antibody colloidal gold method (hereafter refers to as colloid gold law) to examine upper gastrointestinal hemorrhage with a positive rate 60.4%, under examination hemorrhage with positive rate 77.6%; transferrin monoclonal antibody colloidal gold method (hereafter refer to as transferrin law) to examine upper gastrointestinal hemorrhage with a positive rate 82.3%, examination hemorrhage of lower digestive tract with a positive rate 66.4%; The union examination law (hemoglobin and transferrin to be detected twice, once positive that is positive) examines upper gastrointestinal hemorrhage the positive rate is 90.8%, hemorrhage of lower digestive tract's positive rate is 97.6%.

CONCLUSIONExcrement transferrin has the high detection rate in the upper gastrointestinal hemorrhage; Hb and the Tf combined examination may obviously raise the digestive tract hemorrhagic disease's positive detection rate.

Feces ; chemistry ; Gastrointestinal Hemorrhage ; diagnosis ; Gold Colloid ; Humans ; Occult Blood ; Transferrin ; analysis

Ochratoxin A (OTA) is a toxic secondary metabolite mainly produced by Aspergillus and Penicillium species, existing in a variety of foodstuffs and Chinese medicines. OTA is difficult to be detected in practice because of the characteristics such as trace amounts, toxicity, existing in complex matrices. In the numerous detection technologies, colloidal gold chromatographic techniques are highly sensitive, specific, cost-effective and user-friendly, and are being used increasingly for OTA screening. Recently, with the development of aptamer technology and its application in chromatographic technique, a newly colloidal gold aptamer chromatographic technique has been developed. This review elaborates the structures and principles of both traditional and newly colloidal gold chromatographic techniques, focuses on newly colloidal gold aptamer chromatographic technique, summarizes and compares their use in rapid detection of OTA. Finally, in order to provide a reference for better research of related work, the development trends of this novel technique are prospected.
Base Sequence ; Chromatography ; methods ; Gold Colloid ; chemistry ; Molecular Sequence Data ; Ochratoxins ; analysis

OBJECTIVETo investigate the specificity of the dual-functionalized nanoparticles probes (NPs) self-assembled with colloidal gold.

METHODS13-nm gold nanoparticles were prepared with citrate reduction of HAuCl(4). These gold nanoparticles were sequentially functionalized with the specific single-strand oligonucleotide of HA gene of influenza A virus (H1N1) and disulfide molecules of m/z at 693. The NPs solution showed the red formation. The magnetic microparticles (MPs) were modified with another specific single-strand oligonucleotide in HA gene of H1N1. The sandwich complexes (MP-Target-NPs) were formed by the target DNA with the MPs and the NPs. The color change in the solution was observed and the dehybridization product was detected by MALDI TOF MS. Moreover specificity of the probes was investigated with nano-water (as a blank control) and the different target DNAs including complementary DNA,non-complementary DNA and two DNAs of one base mismatch, respectively.

RESULTThe red formation and the positive signal in MS detection of reporter mass code 693 ([M+Na](+)) were observed,which indicated the formation of sandwich complexes formed only when the completely complementary target DNAs were presented in the solution. No color formation changes and no peak signal detected by MALDI TOF MS were observed,showing that none of target of interest (nano-pure water),non-complementary DNA and two DNAs of one base mismatch existed in the systems,which indicated no sandwich complexes formed between the target DNAs and the two probes.

CONCLUSIONConsidering the simple preparation procedure and high specificity,the dual-functionalized gold nanoparticle probes would be widely and increasingly used in nucleic acid analysis. In particular,it would have broad application prospects in early diagnosis of diseases,single nucleotide polymorphism (SNP) typing and so on.

DNA Probes ; chemistry ; Gold Colloid ; chemistry ; Influenza A Virus, H1N1 Subtype ; genetics ; Metal Nanoparticles ; chemistry ; Oligonucleotides ; genetics ; Sensitivity and Specificity

To develop a specific, rapid, and convenient immunochromatography assay (ICA) to detect melamine residues in dairy products and feed sample. Colloidal gold particles labeled with purified monoclonal antibody against anti-melamine were used as the detector reagent. The MEL-OVA (the conjugate of melamine and ovalbumin) and goat anti-mouse melamine IgG were blotted on the test and control regions of nitrocellulose membrane. The strip was then assembled with sample pad, absorbing pad, and dorsal shield. The limit of detection (LOD) is 50 microg/L. The test trip was applied to detect melamine in milk, milk powder, and animal feeds, with detection limits of 100 microg/L for milk, 100 ng/g for milk powder, 200 ng/g for feeds. Compared to LC-MS/MS, the ICA could be used to screen a large number of dairy products and feed samples for melamine residue.
Animals ; Antibodies, Monoclonal ; chemistry ; Cattle ; Dairy Products ; analysis ; Food Contamination ; analysis ; Gold Colloid ; chemistry ; Immunochromatography ; methods ; Milk ; chemistry ; Reagent Strips ; chemical synthesis ; chemistry ; Sensitivity and Specificity ; Triazines ; analysis

OBJECTIVETo detect 3-dimensional images of anti-N-methyl-D-aspartate receptor Nr1 (NMDAr1) polycolonal IgG affixed on mica in physiological environment.

METHODSThe images and data were obtained from a contact mode and commercial Si3N4 probed tip by using atomic force microscope (AFM).

RESULTSThe anti-NMDAr1 polycolonal IgG has a characteristic structure described as an ellipse spherical shape of 136.4 A x 62.8 A x 26.1 A. On the section of the ellipse edge there were two peaks about 13 nm in width.

CONCLUSIONSUsing AFM to investigate biomacromolecule can make us deeply understand the structure of IgG, which will instruct us to detect the membrane receptor protein as a labelling agent.

Adsorption ; Aluminum Silicates ; Gold Colloid ; Imaging, Three-Dimensional ; methods ; Immunoglobulin G ; chemistry ; Microscopy, Atomic Force ; methods ; Receptors, N-Methyl-D-Aspartate ; chemistry

To establish a novel colloidal gold immunochromatography assay (GICA) for rapid, sensitive and accurate detection of Haemophilus influenzae infection by using the outer membrane protein P6 as detection target. First, the linear antigen epitope located in the extracellular domain of the P6 protein (GenBank accession number: AGH02799) was predicted by bioinformatics analysis. The region (62-75 aa of the protein) with strong antigen specificity was chosen and synthesized. Two rabbits were then immunized by the polypeptides (14 aa) for production of polyclonal antibodies. Then, the recombinant P6 proteins were also obtained to produce polyclonal antibodies. Finally, based on the two antibodies, a novel colloidal GICA for detection of Haemophilus influenzae infection was established and the specificity, sensitivity, repeatability and stability of this method were evaluated. At the same time, the method was tested in clinical simulation, and the plate culture method was used to verify its accuracy. The test strip for Haemophilus influenzae infection was successfully prepared. The detection limit of the test strip was as low as 1×105 CFU/mL and the whole process can be completed within 15 minutes. The strip specifically recognized Haemophilus influenzae and did not react with nine of other common respiratory pathogens such as Streptococcus pneumoniae, Moraxella catarrhalis, Mycoplasma pneumonia, and Legionella pneumophila. And the strips could be stored at 25 °C for at least 6 months without losing sensitivity or specificity. The coincidence rate between the results of 200 clinical samples and the plate culture method was 90.5%. Haemophilus influenzae protein P6, which possessed a high degree of surface antigen accessibility and antigencity, could be used as a marker for Haemophilus influenzae detection. The immunochromatographic colloidal gold test strip which bears the features of rapidity, convenience and sensitivity provides a unique tool for the on-site surveillance and diagnosis of Haemophilus influenzae infection in clinical test.
Animals ; Chromatography, Affinity ; instrumentation ; Diagnostic Tests, Routine ; standards ; Gold Colloid ; chemistry ; Haemophilus Infections ; diagnosis ; Haemophilus influenzae ; Humans ; Limit of Detection ; Rabbits ; Sensitivity and Specificity

Antibodies, Viral ; blood ; Betacoronavirus ; immunology ; Coronavirus Infections ; diagnosis ; Gold Colloid ; chemistry ; Humans ; Immunoassay ; methods ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Pandemics ; Pneumonia, Viral ; diagnosis ; Reagent Kits, Diagnostic

Rice stripe virus (RSV) causes dramatic losses in rice production worldwide. In this study, two monoclonal antibodies (MAbs) 16E6 and 11C1 against RSV and a colloidal gold-based immunochromatographic strip were developed for specific, sensitive, and rapid detection of RSV in rice plant and planthopper samples. The MAb 16E6 was conjugated with colloidal gold and the MAb 11C1 was coated on the test line of the nitrocellulose membrane of the test strip. The specificity of the test strip was confirmed by a positive reaction to RSV-infected rice plants and small brown planthopper (SBPH), and negative reactions to five other rice viruses, healthy rice plants, four other vectors of five rice viruses, and non-viruliferous SBPH. Sensitivity analyses showed that the test strip could detect the virus in RSV-infected rice plant tissue crude extracts diluted to 1:20 480 (w/v, g/mL), and in individual viruliferous SBPH homogenate diluted to 1:2560 (individual SPBH/μL). The validity of the developed strip was further confirmed by tests using field-collected rice and SBPH samples. This newly developed test strip is a low-cost, fast, and easy-to-use tool for on-site detection of RSV infection during field epidemiological studies and paddy field surveys, and thus can benefit decision-making for RSV management in the field.
Antibodies, Monoclonal/chemistry* ; China ; Chromatography, Affinity/methods* ; Collodion/chemistry* ; Colloids/chemistry* ; Gold Colloid/chemistry* ; Materials Testing ; Membranes, Artificial ; Oryza/virology* ; Plant Diseases/virology* ; Reproducibility of Results ; Sensitivity and Specificity ; Species Specificity ; Tenuivirus/isolation & purification*