A novel electrochemical immunoassay for cardiac troponin Ⅰ （cTnI） combining the concepts of the dual monoclonal antibody ＂sandwich＂ principle, the silver enhancement on the nano-gold particle, and the SBA-15 mesoporous modified carbon paste electrode （SBA-MCPE） is described. Four main steps were carried out to obtain the analytical signal, i.e., electrode preparation, immunoreaction, silver enhancement, and anodic stripping voltammetric detection. A linear relationship between the anodic stripping peak current and concentration of cTnI from 0.5 to 5.0 ng/mL and a limit of detection of 0.2 ng/mL of cTnI were obtained.
Nong Yue HEHui Shi GUODi YANGChun Rong GUJi Nan ZHANG
High-throughput SNP detection microarrays were used here to explore the relationship between 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T and the risk of gastric carcinoma among population in Jiangsu region,by genotyping the specimens from 170 patients with gastric carcinoma and 140 age-and sex- matched control subjects.PCR products were spotted onto a 3-aminopropyltriethoxysilane coated glass slide to fabricate a microarray,then interrogated by hybridization with dual-color probes (Cy3,CyS) to determine the SNP genotype of each sample,and the relation between the genotypes and the risk of gastric carcinoma was analyzed.The frequencies of C677T genotype were CC(47.9%),CT(40%),CT(12.1%) in control group and CC(35.9%),CT(45.9%),TT(18.2%) in gastric carcinoma group,respectively.The individuals with 677CT+TT genotype group or 677TT had a 1.67-fold (95% CI:1.06-2.64) or 2.67-fold (95% CI:1.382-5.341) increased risk to develop gastric carcinoma compared with those having 677CC genotype. It was shown that the single nucleotide polymorphisms in the MTHFR gene are associated with the risk of gastric carcinoma in the Chinese population.
A novel typography technique was developed to in situ synthesize oligonucleotide arrays on glass slide,which has the celerity,high spatial resolution,lower cost,reliable operation,and high synthetic efficiency.The principle and process of the typography technique for fabricating gene-chips have been described in detail.A suit of poly(terafluoroethylene)devices for synthesizing oligonucleotide arrays were designed and prepared,and the fiber tubes with a number of nano-or micron-channels were em- ployed.The oligonucleotide arrays of 16 and 160 features with four different probes were synthesized using the typography technique.The four specific oligonucleotide probes including the matched and the mismatched by the fluorescent target sequence gave obviously different hybridization fluorescent signals.It was indicated that the gene-chip fabricated by the typography method could be used to rapidly screen single-nucleotide polymorphisms(SNP)and to detect mutations.
TANG JianXin 1,2 ,HE NongYue 1,2,3 &LI Song 1 1State Key Laboratory of Bioelectronics,Southeast University,Nanjing 210096,China
A rapid, inexpensive, reliable, and flexible quantitative immunoassay for cardiac troponin I （cTnI） based on the concepts of one-step dual monoclonal antibody “sandwich” principle. The low density protein array, the nanogold probe, and the silver enhancement on the gold particle were provided. The whole detection procedure of the assay could be fulfilled within 40 min with the pretreated colloidal gold-labeled detection antibody and supporting substrate. The assay showed good specific response to cTnI with very low cross-reactivity ratio to the skeletal isoforms of troponin I （sTnI）, cardiac troponin T （cTnT）, and myoglobin. 588 serum samples were assayed simultaneously by enzyme-linked immuno sorbent assay （ELISA） and this colloidal gold method to test the validity of the method and the data were analyzed using the statistical package SPSS version 11.0 （SPSS Inc.）. There was no significant difference between these two assays （P=0.66〉0.05）. The agreement between this method （〉 or 〈0.3 ng/mL） and ELISA was 86%.
Nong Yue HEHui Shi GUODi YANGChun Rong GUZhi Ping BIANWen Hui WANJi Nan ZHANG
A novel maskless technique, self-driving micro-fluid porous type printing （SMPTP）, was reported to in situ synthesize oligonucleotide arrays on glass slide, which has the merits of low cost, high quality and simple craft. In SMPTP for fabricating gene- chips, porous fiber tubes with a number of nanometric or micron channels functioned as ＂active letters＂ and were assembled in designed patterns, which are identical to the distribution of monomers in each layer of the array, and four patterns were needed for each layer. By means of capillarity, the synthesis solution was automatically taken into porous tubes assembled in a printing plate and reached the surface. An oligonucleotide array of 160 features with four different 15-mer probes was in situ synthesized using this technique. The four specific oligonucleotide probes, including the matched and the mismatched by the fluorescent target sequence, gave obviously different hybridization fluorescent signals.
