A label-free electrochemical method was developed for sensitive determination of ten-eleven translocation protein 1 (TET1) which can mediate the demethylation of DNA. This strategy is mainly based on MspI-mediated restriction endonuclease reaction. Current response difference of the biosensor before and after cleavage by MspI was dependent on the activity and concentration of TET1. With the aid of Au nanoparticles, this method shows a good linear range from 0.0042 μg μL-1 to 0.0210 μg μL -1 with a correlation coefficient of 0.9350 and a low limit of detection 0.00098 μg μL -1. Finally, this method was used to investigate the effects of n-oxalylglycine (NOG) and taxol on activity of TET1. The results indicated that NOG could inhibit TET1 activity but taxol could not. So this electrochemical biosensor could be applied to TET activity evaluation and inhibitor screening in field of biomedicine and clinical diagnosis.Colorectal cancer (CRC) develops from polyps in the inner large intestine or rectum and an increasing incidence and high mortality rate has been observed in humans. Currently, colonoscopy is the preferred modality for early CRC diagnosis. However, this technique has several limitations, such as high medical costs and intricate procedures, leading to increasing demands for the development of a new, simple, and affordable diagnostic method. In this study, an advanced electrochemical biosensor based on rationally designed affinity peptides was developed for discriminating adenoma to carcinoma progression. Amino acid-substituted and rationally designed synthetic peptides (BP3-1 to BP3-8) based on in silico modeling studies were chemically synthesized, and covalently immobilized onto a gold electrode using aromatic ring compounds through surface chemistry techniques. The binding performance of the developed sensor system was observed using square wave voltammetry (SWV). The peptide BP3-2 was selected depending on its relative binding affinity; SWV indicated the limit of detection of BP3-2 for LRG1 to be 0.025 μg/mL. This sensor could distinguish the adenoma-carcinoma transition with improved binding abilities (specificity and selectivity), and stability in plasma samples spiked with LRG1 and real samples from patients with CRC. These results indicate that this electrochemical sensor system can be used for early monitoring of the colorectal adenoma to carcinoma progression.New drugs and illicit synthesized mixtures detection at crime scenes is a great challenge for detection method, which requires anti-interference and ultrasensitive methods to detect methamphetamine (METH) in seized street samples and biological fluids. Herein, we constructed a surface-enhanced Raman sensing method based on aligner mediated cleavage (AMC) of nucleic acid for quantitative detection of METH for the first time. This method we proposed relied on AMC to achieve programmable sequence-specific cleavage of METH aptamer linked by gold nanoparticles (METH aptamer-Au NPs), the cleavage product-Au NPs conjugates (cleavage aptamer-Au NPs) would hybridize with complementary DNA (cDNA)-Au NPs, resulting in the aggregation of the Au NPs and concomitant plasmonic coupling effect. Besides, due to the base number of METH aptamer-Au NPs was decreased, the interparticle distance of the Au NPs was shortened, which increased the electric field enhancement factor. Thus, under the irradiation of the laser, rhodamine 6G (R6G) adsorbed on Au NPs generated a strong Raman signal. The detection limit reached 7 pM, the linear range was from 10 pM to 10 nM, and this detection method also showed good anti-interference ability and reproducibility in serum.Signal amplification is a key step that determines the sensitivity of molecular assays. https://www.selleckchem.com/btk.html Although studies on aptamers have mostly focused on their target-binding ability, taking advantage of the gene-coding function of nucleic acids, we demonstrate here that aptamers can be engineered into diagnostic reagents that can both recognize a target and generate highly amplified detection signals. We developed a strategy that employs a 'readable' aptamer that consists of a single-stranded aptamer and a double-stranded reporter gene. After binding to its target via the aptamer region, the reporter gene of the readable aptamer produces amplified number of signal-generating enzymes through a subsequent in vitro expression reaction. In contrast to conventional enzyme-conjugation methods, this method allows the generation of far more amplified detection signals, thereby markedly increasing the sensitivity of detection enough to analyze a target present in aM concentrations.In this paper, a novel ratiometric electrochemical Cu(II) sensing strategy was established by monitoring the changes of the reduction peaks of Cu(II) and paracetamol based on bare electrode. The paracetamol was adopted as an optimal ratiometric reference (rather than classic ferrocene (Fc) and methylene blue (MB)) due to its highly stability and suitable reduction peak, which is well-separated from the reduction peak of Cu(II). Adopting paracetamol as the internal reference, the reproducibility of this sensing strategy was obviously enhanced. The sensing platform is very cheap in cost and avoids some time-consuming electrode modification process, which is helpful for low-cost and rapid detection.In this paper, a novel adsorbent based on aptamer was prepared via "thiol-ene" click chemistry reaction and used for selective adsorbing the trace phthalic acid esters (PAEs) from drinking water and juice samples, which depended on the group selectivity of aptamers to the ester and the benzoyl groups of PAEs. The morphological structures of the obtained adsorbents were characterized by Fourier Transform infrared spectroscopy (FT-IR), fluorescence spectra, Energy Dispersive Spectrometer (EDS), Brunauer-Emmett-Teller (BET). The selectivity of the prepared adsorbent was evaluated and the results showed that the recovery of the adsorbent with aptamer for PAEs was 66.10-108.90%, while the recovery of adsorbent without aptamer was only 32.41-37.59%. The limit of detection (LOD) (S/N = 3) and limit of quantitation (LOQ) (S/N = 10) of PAEs coupled with HPLC-UV were obtained in the range of 0.11-0.88 μg L-1 and 0.22-1.33 μg L-1, respectively. This work gave a facile and efficient approach to for specific enrichment and highly sensitivity detection of PAEs.