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

This paper provides a brief overview of the current research activities which focused on the bio-application of gold magnetic nanocomposite particles. By combining the magnetic characteristics of the iron oxide core with the unique features of nano-gold particles such as targeting by surface modification and optical properties, such composite nanoparticles have a wide range of applications in cancer hyperthermia, CT and MRI imaging, bio-separation, bio sensors, gene diagnosis, drug targeting and many other biomedical fields.
Diagnostic Imaging ; Drug Delivery Systems ; Ferric Compounds ; chemistry ; Gold ; chemistry ; Humans ; Magnetics ; Nanocomposites ; chemistry ; Nanoparticles ; chemistry ; Neoplasms

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

Heavy metal leftover on farm and stock products has become a big threat to human. It is necessary to develop some fast and efficient detection methods. Heavy metal immunoassays are new methods for detection of heavy metal ions. Compared to the traditional chemical methods, immunoassays are not only fast, cheap, simple, but also reasonably portable, highly sensitive and selective. It can be used as preliminary screening for rapid determination of heavy metal ions. Except chemical chelators, phytochelatin and metallothionein can also be used for preparing immunogen, both of them can chelate heavy metal ions to carrier protein. There are two prototype assays: polyclonal antibody immunoassay and monoclonal antibody immunoassay. The former includes fluorescence polarization immunoassay; the latter includes indirectly competitive ELISA, one-step competitive immunoassay and KinExA immunoassay. Among these assays, indirectly competitive ELISA which was used for determining heavy metal ions in the early days was easy to be interfered and showed false positive. Fluorescence polarization immunoassay which used polyclonal antibody for determining heavy metal ions was simple and cheap. KinExA instrument could be functioned as an immunosensor for environmental samples. One-step immunoassay which avoided to the addition of second antibody and chromogenic substrate was simple and sensitive. Colloidal gold enhanced immunochromatography assay is a semi-quantitation for determining heavy metal ions. As an adjunctive way for chemical methods, it has the potential application in rapid determination of heavy metal ions.
Animals ; Antibodies, Monoclonal ; immunology ; Gold ; chemistry ; Humans ; Immunoassay ; methods ; Metals, Heavy ; analysis ; immunology

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

The surface plasmon resonance (SPR)-based gene chip was prepared according to the following processes: First, a film of nanogold, which was synthesized by using Frens' method, was plated on chip by Chlorauric acid/hydroxylamine method. Then probes were fixed on nanogold film by Self-assembled monolayer (SAM) technology. Subsequently, the fixing time and concentration of probes, the sensitivity and the specificity of the chip were optimized. Our results suggested that the chip plated with 2.5 nm nanogold film has a better SPR reflection, and when fixed by probes for 4.5 h at the concentration of 1 500 nmol/L, the gene chip also shows a fine performance of detection and can identify accurately the mismatch between bases in SPR detection system. The gene chip constructed in the research can be used for SPR sensor detection.
Gold ; chemistry ; Nanoparticles ; chemistry ; Neisseria gonorrhoeae ; genetics ; Oligonucleotide Array Sequence Analysis ; Sensitivity and Specificity ; Surface Plasmon Resonance ; methods

This paper reports the surface morphology and I-V curves of porous silicon (PS) samples and related devices. The observed fabrics on the PS surface were found to affect the electrical property of PS devices. When the devices were operated under different external bias (10 V or 3 V) for 10 min, their observed obvious differences in electrical properties may be due to the different control mechanisms in the Al/PS interface and PS matrix morphology.
Electrochemistry ; instrumentation ; methods ; Electrodes ; Electromagnetic Fields ; Gold ; chemistry ; Materials Testing ; Molecular Conformation ; Porosity ; Silicon ; chemistry ; Surface Properties

OBJECTIVETo evaluate the effect of aurum coating on corrosion resistance of Ni-Cr alloy in artificial saliva environment.

METHODSThe corrosion potential (E(corr)), self-corrosion current density (I(corr)), and polarization resistance (R(p)) of three alloys were measured using electrochemical methods to compare the difference of corrosion resistance between aurum-coated Ni-Cr alloy and Ni-Cr alloy or Au alloy. Meanwhile, microstructural and phase diffraction was examined with field scanning electromicroscopy (FSEM) and surface chemical analysis was performed by energy diffraction X-ray (EDX).

RESULTSThe I(corr) of aurum-coated Ni-Cr alloy was (0.70 +/- 0.20) x 10(-6) A/cm2, which was significantly higher than that of Au alloy (P < 0.05) and lower than that of Ni-Cr alloy (P < 0.05). R(p) of aurum-coated Ni-Cr alloy was (34.77 +/- 12.61) KOmega.cm2, which was higher than that of Ni-Cr alloy (P < 0.05) and lower than that of Au alloy (P < 0.05). The results of FSEM showed that the corrosion resistance of Ni-Cr alloy coated with aurum was better than that of Ni-Cr alloy. The results of EDX indicated that released Ni and Cr of Ni-Cr alloy coated with aurum after test were less than those of Ni-Cr alloy (P < 0.05).

CONCLUSIONSThe corrosion resistance of aurum-coated Ni-Cr alloy is higher than that of Ni-Cr alloy.

Chromium Alloys ; chemistry ; Corrosion ; Electrochemistry ; Gold Alloys ; chemistry ; Metal Ceramic Alloys ; chemistry ; Microscopy, Electron, Scanning ; Nickel ; chemistry ; Saliva, Artificial ; chemistry ; Surface Properties