scholarly journals An isothermal, non-enzymatic, and dual-amplified fluorescent sensor for highly sensitive DNA detection

2021 ◽  
Vol 40 (1) ◽  
pp. 312-322
Author(s):  
Idorenyin Iwe ◽  
Zhigang Li
Keyword(s):  
Thermal Cycling ◽  
Signal Amplification ◽  
Fluorescent Sensor ◽  
Serum Samples ◽  
Practical Applications ◽  
Highly Sensitive ◽  
Dual Stage ◽  
Catalytic Hairpin Assembly ◽  
Nucleic Acid Assay ◽  
Fetal Bovine

Abstract Sensitive DNA assays are of importance in life science and biomedical engineering, but they are heavily dependent on thermal cycling programs or enzyme-assisted schemes, which require the utilization of bulky devices and costly reagents. To circumvent such requirements, we developed an isothermal enzyme-free DNA sensing method with dual-stage signal amplification ability based on the coupling use of catalytic hairpin assembly (CHA) and Mg2+-dependent deoxyribozyme (DNAzyme). In this study, the sensing system involves a set of hairpin DNA probes for CHA (ensuring the first stage of signal amplification) as well as ribonucleobase-modified molecular beacons that serve as activatable substrates for DNAzymes (warranting the second stage of signal amplification). An experimentally determined detection limit of about 0.5 pM is achieved with a good linear range from 0.5 to 10 pM. The results from spiked fetal bovine serum samples further confirm the reliability for practical applications. The non-thermal cycling, enzyme-free, and dual-amplified features make it a powerful sensing tool for effective nucleic acid assay in a variety of biomedical applications.

scholarly journals A Universal Proximity CRISPR Cas12a Assay for Ultrasensitive Detection of Nucleic Acids and Proteins

2019 ◽  
Author(s):  
Yongya Li ◽  
Hayam Mansour ◽  
Yanan Tang ◽  
Feng Li
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Signal Amplification ◽  
Target Recognition ◽  
Homogeneous Solution ◽  
Ultrasensitive Detection ◽  
Primer Extension Reaction ◽  
Serum Samples ◽  
Highly Sensitive ◽  
Assay Design

AbstractHerein, we describe a proximity CRISPR Cas12a assay that harnesses “collateral” single-stranded DNase activity of Cas12a as a universal amplifier for the ultrasensitive detection of nucleic acids and proteins. The target recognition is achieved through proximity binding rather than recognition by CRISPR RNA (crRNA), which allows the flexible assay design and expansion to proteins. A binding-induced primer extension reaction is then used to generate a predesigned CRISPR-targetable sequence as a barcode for signal amplification. We demonstrate that our assay is highly sensitive and universal. As low as 1 fM nucleic acid target could be detected isothermally in a homogeneous solution via the integration with nicking cleavage. We’ve also successfully adapted the assay for the sensitive and wash-free detection of antibodies in both buffer and diluted human serum samples.

scholarly journals A highly sensitive and selective on–off fluorescent sensor based on a complex of polySchiff-Fe2+ for Cr(vi) detection in an aqueous medium

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8963-8969
Author(s):  
Zhiying Li ◽  
Congshu Li ◽  
Huiyun Yan
Keyword(s):  
Aqueous Medium ◽  
Fluorescent Sensor ◽  
Human Race ◽  
Safety And Health ◽  
Highly Sensitive

Designing exceptional probes to detect minute quantities of chromium(vi) is of huge importance for the safety and health of the human race.

A highly sensitive electrochemical microRNA-21 biosensor based on intercalating methylene blue signal amplification and a highly dispersed gold nanoparticles/graphene/polypyrrole composite

The Analyst ◽  
2021 ◽  
Vol 146 (8) ◽  
pp. 2679-2688
Author(s):  
Chammari Pothipor ◽  
Noppadol Aroonyadet ◽  
Suwussa Bamrungsap ◽  
Jaroon Jakmunee ◽  
Kontad Ounnunkad
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Signal Amplification ◽  
Electrochemical Biosensor ◽  
Highly Sensitive ◽  
Highly Dispersed ◽  
Polypyrrole Composite ◽  
Amplification Strategy ◽  
Dispersed Gold ◽  
Potential Tool

An ultrasensitive electrochemical biosensor based on a gold nanoparticles/graphene/polypyrrole composite modified electrode and a signal amplification strategy employing methylene blue is developed as a potential tool for the detection of miRNA-21.

scholarly journals Metal Nanoparticle and Quantum Dot Tags for Signal Amplification in Electrochemical Immunosensors for Biomarker Detection

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 85
Author(s):  
Anton Popov ◽  
Benediktas Brasiunas ◽  
Asta Kausaite-Minkstimiene ◽  
Almira Ramanaviciene
Keyword(s):  
Signal Amplification ◽  
Electrochemical Immunosensor ◽  
Metal Nanoparticle ◽  
Biomarker Detection ◽  
Analytical Instruments ◽  
Electrochemical Immunosensors ◽  
Highly Sensitive ◽  
Recent Developments ◽  
Electrochemical Signal ◽  
Detection Of Biomarkers

With the increasing importance of healthcare and clinical diagnosis, as well as the growing demand for highly sensitive analytical instruments, immunosensors have received considerable attention. In this review, electrochemical immunosensor signal amplification strategies using metal nanoparticles (MNPs) and quantum dots (Qdots) as tags are overviewed, focusing on recent developments in the ultrasensitive detection of biomarkers. MNPs and Qdots can be used separately or in combination with other nanostructures, while performing the function of nanocarriers, electroactive labels, or catalysts. Thus, different functions of MNPs and Qdots as well as recent advances in electrochemical signal amplification are discussed. Additionally, the methods most often used for antibody immobilization on nanoparticles, immunoassay formats, and electrochemical methods for indirect biomarker detection are overviewed.

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