Enrichment–Stowage–Cycle Strategy for Ultrasensitive Electrochemiluminescent Detection of HIV-DNA with Wide Dynamic Range

Abstract

Sensitive detection of human immunodeficiency virus DNA (HIV-DNA) is essential for timely diagnosis and cure of the illness. Herein, a novel “enrichment–stowage–cycle” strategy was proposed to fabricate a multiple amplified electrochemiluminecence (ECL) biosensor for HIV-DNA detection. On the basis of the enrichment role of magnetic nanobeads, assembly role of copolymer nanospheres and strand displacement amplification (SDA), the processes were named as “enrichment”, “stowage”, and “cycle”, respectively. The method employed electrochemiluminescent nanospheres (ENs) as signal labels by assembling three layers of CdSe/ZnS quantum dots (QDs) onto the surface of copolymer nanospheres. Compared to QDs, the same concentration of ENs can the enhance the ECL intensity by about 11.3-fold. SDA could further amplify the signals by about 3.77-fold, possessing high sensitivity for low-abundant biomarkers detection. The integration of magnetic separation improved detection specificity and stability, making the method possible for practical application. On the basis of magnetic separation, ENs and SDA, the ECL biosensor realized ultrasensitive detection of 39.81 fM HIV-DNA, which was more sensitive than other HIV-DNA analytical methods, with a wide dynamic range of 0.05 pM to 50 nM. The successful detection of HIV-DNA in complex samples with good sensitivity and accuracy indicated its potential utilization in early judgment of diseases and fabrication of signal amplification platforms.

Chemiluminescence assay for kanamycin based on target recycling strategy

“…The hairpin structure HP1 containing the kanamycin aptamer was combined with carboxyl‐modified MBs through amidation reaction between carboxyl group of MBs and amino of HP1. [ 24 ] Relying on base complementation, the sDNA labelled with LumAuNPs was linked with MB‐HP1 to form MB‐HP1‐sDNA‐LumAuNPs that could specifically recognize kanamycin. When kanamycin was present in the system, it was accurately recognized by MB‐HP1‐sDNA‐LumAuNPs, the hairpin structure HP1 containing the kanamycin aptamer sequence bound to kanamycin and LumAuNPs–sDNA which could generate CL signals were released.…”

“…The hairpin structure HP1 containing the kanamycin aptamer was combined with carboxyl-modified MBs through amidation reaction between carboxyl group of MBs and amino of HP1. [24] Relying on base complementation, the sDNA labelled with LumAuNPs was linked with MB-HP1 to form MB-HP1-sDNA-LumAuNPs that could specifically recognize kanamycin.…”

Contribution of magnetic particles in molecular diagnosis of human viruses

“…MNPs incorporation boosted specificness for detection as well as constancy, driving the above-mentioned scheme suitable for real-world utilizations. Efficacious recognition regarding HIV-DNA inside composite samples, for instance in milk, FBS (fetal bovine serum), urine, plus blood) showed its probability for diagnosis on time as well as precise quantification of biomarkers present in actual samples with low concentration [ 92 ]. Enriching concerning target compounds, impurities exclusion, in addition to decontamination of recognized analytes offers pronounced accuracy along with opportuneness intended for future research.…”

Magnetic Nanobeads and De Novo Growth of Electroactive Polymers for Ultrasensitive microRNA Detection at the Cellular Level

“…Taking advantage of its high sensitivity, fast response, easy miniaturization, and portability, an electrochemical sensor exhibits great application prospects in accurate miRNA analysis, but it is difficult to realize cell level detection for several reasons. First, the low content, small size, and high homology of miRNAs bring great challenges for the separation and detection of miRNAs in biological samples. , Second, great interference in complex samples can easily produce false-negative results by poisoning the working electrodes or false-positive results by nonspecific adsorption . It is hard to sample directly using this method from a complex matrix.…”

“…With the development of nanomaterials and methodology, various signal amplification strategies have been introduced into the construction of electrochemical sensors to improve detection sensitivity. The main amplification mechanisms can be divided into three categories: (i) conductive substrate modification to improve the specific surface area of working electrodes and the electron transfer rate between electroactive substances and electrodes; − (ii) polymerase chain reaction, enzyme digestion reaction, or strand displacement amplification (SDA) is introduced to realize target cycle magnification; − (iii) appropriate materials are used as carriers or bridges to increase the load of signal labels. ,, For example, monolayer gold nanoisland film modified electrodes amplified the analytical signals by about 2.3-fold compared with bare indium tin oxide (ITO) electrodes . Through SDA, the target could be cycled many times and 0.76 pM HIV-DNA detection was realized .…”