A tag-free fluorescent aptasensor for tobramycin detection using a hybridization of three aptamer strands and SYBR Green I dye

Zahraee, Hamed; Khoshbin, Zahra; Ramezani, Mohammad; Alibolandi, Mona; Abnous, Khalil; Taghdisi, Seyed Mohammad

doi:10.1016/j.saa.2022.122305

Cited by 20 publications

(4 citation statements)

References 43 publications

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“…For these reasons, aptamers are used in many analytical fields, such as diagnosis, drug and blood analysis. [41][42][43][44][45] The high affinity for the target analyte leads to high stability of the complex aptamer-analyte, low detection limits, 46,47 and in some cases, the possibility of reusing the sensor. 48 The development of the microfluidic devices allows for the integration of aptamers into a microfluidic chip, thus obtaining innovative sensor devices (lab-onchip).…”

Section: Aptamer Sensorsmentioning

confidence: 99%

Cortisol sensing by optical sensors

Santonocito,

Puglisi,

Cavallaro

et al. 2024

Analyst

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Section: Aptamer Sensorsmentioning

confidence: 99%

Cortisol sensing by optical sensors

Santonocito,

Puglisi,

Cavallaro

et al. 2024

Analyst

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“…In 5% serum, the K d was 5.6 ± 1.1 μM without stabilization and 5.1 ± 2.0 μM with 10 min stabilization. The literature reported K d for this aptamer is between 6 and 20 μM adenosine [ 18 , 19 , 20 ]. Considering the error associated with this method, there was not a significant difference in K d with or without stabilization, and because all determined K d are only marginally below the lower bound of the reported K d , this demonstrates that the ThT-based titration method can provide valuable information on the strength of target binding in this case.…”

Section: Resultsmentioning

confidence: 99%

“…Sometimes, the change in fluorescence is very small, which can compromise the reliability of this method and make quantitative measurement difficult. For many such assays, the fluorescence intensity drops when target molecules are added and the change in fluorescence intensity is within one-fold, such as in the adenosine aptamer with ThT [ 18 , 19 , 20 , 21 ]. Therefore, it is important that the observed fluorescence drop is due to aptamer binding.…”

Section: Introductionmentioning

confidence: 99%

Surfactant-Assisted Label-Free Fluorescent Aptamer Biosensors and Binding Assays

Zhang

Liu

2023

Biosensors

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Using DNA staining dyes such as SYBR Green I (SGI) and thioflavin T (ThT) to perform label-free detection of aptamer binding has been performed for a long time for both binding assays and biosensor development. Since these dyes are cationic, they can also adsorb to the wall of reaction vessels leading to unstable signals and even false interpretations of the results. In this work, the stability of the signal was first evaluated using ThT and the classic adenosine aptamer. In a polystyrene microplate, a drop in fluorescence was observed even when non-binding targets or water were added, whereas a more stable signal was achieved in a quartz cuvette. Equilibrating the system can also improve signal stability. In addition, a few polymers and surfactants were also screened, and 0.01% Triton X-100 was found to have the best protection effect against fluorescence signal decrease due to dye adsorption. Three aptamers for Hg2+, adenosine, and cortisol were tested for their sensitivity and signal stability in the absence and presence of Triton X-100. In each case, the sensitivity was similar, whereas the signal stability was better for the surfactant. This study indicates that careful control experiments need to be designed to ensure reliable results and that the reliability can be improved by using Triton X-100 and a long equilibration time.

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“…Depending on how the fluorescence signal is generated, the corresponding sensors can be classified into unlabeled and labeled types [33]. The unlabeled type usually uses dyes with some toxicity such as SYBR Green and PicoGreen as signal labels [34,35]. The labeled type often involves complex probe preparation, stringent enzyme involvement, and synthesis of nanomaterials, which increases the sensitivity and at the same time increases the difficulty of practical operation, limiting their practical applications [36].…”

Section: Introductionmentioning

confidence: 99%

Self-Responsive Fluorescence Aptasensor for Lactoferrin Determination in Dairy Products

Liu,

Gao,

Qin

et al. 2024

Molecules

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In this study, a self-responsive fluorescence aptasensor was established for the determination of lactoferrin (Lf) in dairy products. Herein, the aptamer itself functions as both a recognition element that specifically binds to Lf and a fluorescent signal reporter in conjunction with fluorescent moiety. In the presence of Lf, the aptamer preferentially binds to Lf due to its specific and high-affinity recognition by folding into a self-assembled and three-dimensional spatial structure. Meanwhile, its reduced spatial distance in the aptamer–Lf complex induces a FRET phenomenon based on the quenching of 6-FAM by amino acids in the Lf protein, resulting in a turn-off of the fluorescence of the system. As a result, the Lf concentration can be determined straightforwardly corresponding to the change in the self-responsive fluorescence signal. Under the optimized conditions, good linearities (R2 > 0.99) were achieved in an Lf concentration range of 2~10 μg/mL for both standard solutions and the spiked matrix, as well as with the desirable detection limits of 0.68 μg/mL and 0.46 μg/mL, respectively. Moreover, the fluorescence aptasensor exhibited reliable recoveries (89.5–104.3%) in terms of detecting Lf in three commercial samples, which is comparable to the accuracy of the HPCE method. The fluorescence aptasensor offers a user-friendly, cost-efficient, and promising sensor platform for point-of-need detection.

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A tag-free fluorescent aptasensor for tobramycin detection using a hybridization of three aptamer strands and SYBR Green I dye

Cited by 20 publications

References 43 publications

Cortisol sensing by optical sensors

Cortisol sensing by optical sensors

Surfactant-Assisted Label-Free Fluorescent Aptamer Biosensors and Binding Assays

Self-Responsive Fluorescence Aptasensor for Lactoferrin Determination in Dairy Products

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