Chemiluminescent aptasensor for chloramphenicol based on N-(4-aminobutyl)-N-ethylisoluminol-functionalized flower-like gold nanostructures and magnetic nanoparticles

A novel chemiluminescent aptasensor for the highly sensitive detection of chloramphenicol (CAP) in milk was successfully developed using biotinylated CAP aptamer-functionalized magnetic nanoparticles (MNPs) as capture probes and thiolated hybridized complementary strand-modified N-(4-aminobutyl)-N-ethylisoluminol (ABEI)-functionalized flower-like gold nanostructures (AuNFs) as signal probes. P-iodophenol (PIP) was also added to form an ABEI-H2O2-PIP steady-state chemiluminescence (CL) system. Based on a competitive format, the CL intensity was negatively correlated with the concentration of CAP in the range of 0.01-0.20 ng/mL and the detection limit was 0.01 ng/mL in buffer and 1 ng/mL in milk. The proposed method was successfully applied to measure CAP in milk samples and compared to a commercial ELISA method. The high sensitivity of AuNFs, excellent selectivity and stability of aptamers, and good overall stability of the chemiluminescent bioassay with magnetic separation make them a promising approach for the detection of small molecular illegal additives. Additionally, the high sensitivity, easy operation, and good reproducibility exhibited by the stable chemiluminescent bioassay demonstrate its applicability for the trace detection of CAP in applications, such as animal husbandry.

Tetrahedral DNA nanostructure-based microRNA biosensor coupled with catalytic recycling of the analyte

MicroRNAs are not only important regulators of a wide range of cellular processes but are also identified as promising disease biomarkers. Due to the low contents in serum, microRNAs are always difficult to detect accurately . In this study, an electrochemical biosensor for ultrasensitive detection of microRNA based on tetrahedral DNA nanostructure is developed. Four DNA single strands are engineered to form a tetrahedral nanostructure with a pendant stem-loop and modified on a gold electrode surface, which largely enhances the molecular recognition efficiency. Moreover, taking advantage of strand displacement polymerization, catalytic recycling of microRNA, and silver nanoparticle-based solid-state Ag/AgCl reaction, the proposed biosensor exhibits high sensitivity with the limit of detection down to 0.4 fM. This biosensor shows great clinical value and may have practical utility in early diagnosis and prognosis of certain diseases.

SERS quantitative analysis of trace HSA with a Coomassie brilliant blue G-250 molecular probe in nanogold sol substrate

A SERS quantitative analysis method was developed for the detection of trace HSA with a Coomassie brilliant blue G-250 probe in nanogold sol substrate.

A dansyl-based fluorescent probe for selectively detecting Cu2+and imaging in living cells

Copper is a crucial transition metal ion that plays an essential role in environmental, biological, and chemical systems.

Synthesis and characterization of fluorescent chitosan–ZnSe/ZnS nanoparticles for potential drug carriers

The objective of the study is to describe a new approach of combining quantum dots into chitosan as an anti-cancer drug carrier.

A Turn-Off Fluorescent Nanosensor for Iron in Aqueous Solution Based on Fluorescent Carbon Nanoparticles

The water-soluble fluorescent carbon nanomaterials with low toxicity and high biocompatibility are considered as promising materials for biomedical and sensor applications. Here, we report that a nanosensor system has been developed to simultaneously detect two valence states of iron ( Fe 2+ and/or Fe 3+) in aqueous solution based on fluorescent carbon nanoparticles (FCNs). The nanosensor has high selectivity and sensitivity with a limit of detection (LOD) of 5 μM, which is equivalent to 0.3 mg/L (5.36 μM) of iron in drinking water by United States Environment Protection Agency (US-EPA). Furthermore, a distinguishable color change of solution, from pale yellow to red-brown, can be observed as iron concentration reaching 40 μM, which provides way for fast, visible detection of irons.

Telomerase as a potential marker for inflammation and cancer detection in bronchial washing: a prospective study

OBJECTIVES

The diagnosis of lung cancer remains difficult especially in peripheral tumors, given the absence of relevant markers and of sensitive imaging techniques. Telomerase is a ribonucleotide enzyme responsible for the immortalization of cancerous cells and seems to increase in bronchial aspirates of lung cancer patients. The purpose of our study is to further investigate the value of telomerase measurement in bronchial aspirates as a diagnostic tool for lung cancer.

DESIGN AND METHODS

Random 82 bronchial aspirates were obtained from patients undergoing bronchoscopy to diagnose any lung illness including inflammation and cancer. Cytology examination, quantification of proteins by Bradford method, and telomerase activity measurement by quantitative Real-time PCR were performed. Out of 82 specimens, 11 were excluded because of hemolysis, absence of elements or lack of final diagnosis. ROC curve analysis was done.

RESULTS

A significant difference in telomerase activity average was noted between normal patients and those with inflammation and cancer. Discriminatory capacity of telomerase activity was: for cancer vs. non cancer, AUC =0.74 (95% CI: 0.62-0.84), sensitivity=78%, specificity=72%, Negative Predictive Value=87%, at cut-off >0.46 atmol/mg protein/20 min; for cancer vs. normal, AUC=0.87 (95% CI: 0.72-0.96), se=78%, sp=92%, NPV=71%, at cut-off >0.46; for cancer vs. inflammation, AUC=0.69 (95% CI: 0.55-0.80), se=74%, sp=70%, NPV=79%, at cut-off >1.03, and for inflammation vs. normal, AUC=0.76 (95% CI: 0.62-0.88), se=79%, sp=77%, NPV=59%, at cut-off >0.

CONCLUSION

Telomerase activity in bronchial aspirates is a promising diagnostic marker for lung cancer and inflammation detection.

Aptamer-mediated chemiluminescence detection of prion protein on a membrane using trimethoxyphenylglyoxal

Effective recognition and quantitative analysis of the prion protein are important in drug discovery and diagnosis for prion diseases, such as bovine spongiform encephalopathy and Creutzfeldt-Jakob diseases. We have developed a high-throughput method for a specific and sensitive determination of prion protein on a solid-phase membrane, based on a chemiluminescence reaction of aptamer with 3,4,5-trimethoxyphenylglyoxal. This method using aptamer is facile, inexpensive and convenient for the detection of the prion protein on a membrane, indicating a lower detection limit of ca. 4.2 pmol spot(-1).

Chemiluminescence platforms in immunoassay and DNA analyses

Chemiluminescent (CL) detection techniques for DNA assays and immunoassays have become very popular in recent years. This review discusses recent advances in those CL assays that have occurred over the last few years. In the monoplex assay section, different classes of CL labels including nanoparticle, DNAzyme, acridinium ester, enzyme and luminol-based CL assays are reviewed concerning the detection of DNAs and proteins. In the multiplex assay section, both spatial resolution and substrate zone-resolved techniques are discussed.