4-Nitrophenol-Loaded Magnetic Mesoporous Silica Hybrid Materials for Spectrometric Aptasensing of Carcinoembryonic Antigen

Aptamer- or antibody-based sensing protocols have been reported for detecting carcinoembryonic antigen (CEA), but most exhibit complicated procedures or multiple reactions. In this work, we developed a one-step aptasensing protocol for the spectrometric determination of CEA based on 4-nitrophenol (4-NP)-loaded magnetic mesoporous silica nanohybrids (MMSNs) for bioresponsive controlled-release applications. To fabricate such a responsive–controlled sensing system, single-stranded complementary oligonucleotides relative to the CEA-specific aptamer were first modified on the aminated MMSN. Thereafter, 4-NP molecules blocked the pores with the assistance of the aptamers via a hybridization reaction. The introduced target CEA specifically reacted with the hybridized aptamer, thus detaching from the MMSN to open the gate. The loaded 4-NP molecules were released from the pores, as determined using ultraviolet–visible (UV–vis) absorption spectroscopy after magnetic separation. Under optimum conditions, the absorbance increased with an increase in the target CEA in the sample and exhibited a good linear relationship within the dynamic range of 0.1–100 ng mL−1, with a detection limit of 46 pg mL−1. Moreover, this system also displayed high specificity, good reproducibility, and acceptable accuracy for analyzing human serum specimens, in comparison with a commercialized human CEA-enzyme-linked immunosorbent assay (ELISA) kit.

Expression of the NSE, SP, NFH and DβH in Normal and Cryptorchid Testes of Bactrian Camel

Background: Neuroendocrine substances play important roles in regulating the normal physiological functions of testicles.The purpose of this study is to explore the localization and effects of four neuroendocrine markers(NSE, SP, NFH and DβH) in normal and cryptorchid testes of Bactrian camels.Methods: The cryptorchid testes were located in the abdominal cavity and were collected by orchiectomy. Fresh testes tissues were processed into small pieces and then divided into three samples. One sample was frozen in liquid nitrogen for western blotting hybridization reaction, while the other sample was fixed with 4% paraformaldehyde solution for histochemical analysis, and the third fixed in glutaraldehyde for transmission electron microscopy observation.Results: The results showed that cryptorchidism caused a reduction in layers of spermatogenic epithelium and decreased glycogen positivity in the basement membrane.The ultrastructure revealed that macrophages were always found around the Leydig cells, which were crowded with swelling mitochondria in cryptorchidism. Expression of NSE in the Leydig cells of cryptorchidism was significantly weakened compared to that in the normal group(p<0.01). We found that SP was always distributed along the nerve fibers in normal testes and was expressed in the Leydig cells of cryptorchidism. However, expression of NFH in the cryptorchidic tissue was strongly positive in spermatogenic epithelium, with limited expression in Leydig cells and no expression in peritubular myoid cells. Therefore, expression of DβH in the Sertoli cells was comparatively strong in both the normal and cryptorchidism groups.NFH and DβH expression was significantly increased in the cryptorchidism group compared with the nomal group(p<0.01).Conclusions: These findings indicated that the underdeveloped seminiferous epithelium and pathological changes in cryptorchid tissue in Bactrian camels were potentially related to a disorder in glycoprotein metabolism.Our results suggest that NSE and SP could helpful to judge the pathological changes of cryptorchidism. The present study provides the first evidence at the protein level for the existence of NFH and DβH in Sertoli and Leydig cells in Bactrian camel cryptorchidism and provides a more in-depth understanding of neuroendocrine regulation is crucial for animal cryptorchidism.

A colorimetric biosensor for ultrasensitive detection of SURF1 gene based on dual DNA-induced cascade hybridization reaction

In this work, a simple and ultrasensitive colorimetric biosensor for detection of SURF1 gene fragments (Leigh syndrome) has been developed based on dual DNA-induced cascade hybridization reaction. Firstly, biotin...

Studies on the interactions of Ag(i) with DNA and their implication on the DNA-templated synthesis of silver nanoclusters and on the interaction with complementary DNA and RNA sequences

Variables affecting the fluorescent properties of DNA-stabilized silver nanoclusters are studied. The secondary structure of the AgNC-stabilizing DNA sequence dramatically affects the analytical signal behind the hybridization reaction.

Simple and Multiplexed Enrichment of Rare DNA Variants via Sequence-Selective and Temperature-Robust Amplification

Rare DNA sequence variants hold important clinical and biological information, but are chal-lenging for existing methods (e.g. PCR, NGS) to profile in an inexpensive, multiplexed, simple-to-implement, and sequence-general way. Here, we present Blocker Displacement Amplification (BDA), a temperature-robust PCR method that selectively amplifies all sequence variants within a roughly 20 nt window by 1000-fold over wildtype sequences, allowing easy detection and quantitation of hundreds of potentials variants originally at ≤0.1% allele frequency. BDA employs a rationally designed competitive hybridization reaction to achieve similar enrichment performance across anneal temperatures ranging from 56°C to 64°C. This temperature robustness facilitates multiplexed enrichment of many different variants across the genome, and furthermore enables the use of in-expensive and portable thermocycling instruments for rare DNA variant detection. To show the sequence generality of BDA, we demonstrated enrichment on 156 single-nucleotide variants (SNVs). BDA has been validated on multiple different PCR platforms, DNA polymerases, and sample types including clinical cell-free DNA samples collected from the blood plasma of lung cancer patients. BDA quantitation of mutation allele fraction is generally consistent with deep sequencing results.