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Systematic Truncating Aptamers to Create High Performance Graphene Oxide (GO)-based Aptasensors for Multiplex Detection of Mycotoxins
摘要： Graphene Oxide (GO)-based aptasensor is currently one of the most popular sensing platforms for simple and rapid detection of various targets. Unfortunately, the GO-based aptasensors with long aptamer strands typically show unsatisfactory performance resulted from insignificant structural transformations upon target bindings. We report herein the utilization of an aptamer truncating strategy to combat such a challenge. Taking a pre-selected anti-aflatoxin B1 (AFB1) aptamer (P-AFB1-50) as a trial system, we sequentially remove the extraneous nucleotides within the aptamer by means of circular dichroism (CD) spectroscopy and binding affinity analysis. Particularly, the ratio of the quenching constants between the GO sheets and the truncated aptamers (labelled with fluorophores) in the absence and presence of target was determined for each of the truncated aptamers to evaluate the optimal sequence. As a result, the truncated aptamer comprising 40 nucleotides was confirmed to show the highest FL output and best detection limit upon conjugation with GO sheets. More importantly, we demonstrated that this truncating strategy is versatile, i.e., it can be easily extended to other aptamer systems (anti-ochratoxin A (OTA) aptamer, P-OTA-61, as an example) for extraneous nucleotide identification. Impressively, the two optimal truncated aptamers can work together on GO sheets to achieve a simultaneous detection of two different mycotoxins (i.e., AFB1 and OTA) in one single testing. Essentially, this research opens a new avenue for the design and testing of aptamer/GO based-sensing platforms for rapid, low-cost and multiplex quantification of analytical targets of interest.
关键词： DNA/GO-based biosensors,AFB1,OTA,long-chain aptamer,multiplex detection,extraneous nucleotide truncation
更新于2025-11-14 15:28:36
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A Label-free Photoelectrochemical Aptasensor Based on N-GQDs Sensitized Zn-SnS2 for Aflatoxin B1 Detection
摘要： A new label-free aptasensor with high visible-light photoelectrochemical (PEC) activity was fabricated for the detection of AFB1 based on N-doped graphene quantum dots (N-GQDs) sensitized Zn doped SnS2 (Zn-SnS2) nanocomposites. N-GQDs sensitized Zn-SnS2 showed eminent PEC performance. Ascorbic acid was utilized as an efficient electron donor for scavenging photogenerated holes and inhibiting light driven electron-hole pair recombination. Under the optimum experimental conditions, the specific binding between AFB1 aptamer and AFB1 resulted in the linear decrease of photocurrent with the increase of logarithm of AFB1 concentration in the range of 0.01 ng mL-1 to 20 ng mL-1 with a detection limit of 3 pg mL-1. The constructed N-GQDs sensitized Zn-SnS2 PEC aptasensor exhibited high sensitivity, low cost and good reproducibility, which is a promising platform for the detection of other important analytes.
关键词： photoelectrochemical aptasensor,N-GQDs,Zn-SnS2,AFB1
更新于2025-09-09 09:28:46