Development of a Soluble KIT Electrochemical Aptasensor for Cancer Theranostics

Abstract

An electrochemical sensor based on a conformation-changing aptamer is reported to detect soluble KIT, a cancer biomarker, in human serum. The sensor was fabricated with a ferrocene-labeled aptamer (K d < 5 nM) conjugated to a gold electrode. Quantitative KIT detection was achieved using electrochemical impedance spectroscopy (EIS) and square-wave voltammetry (SWV). EIS was used to optimize experimental parameters such as the aptamer-to-spacer ratio, aptamer immobilization time, pH, and KIT incubation time, and the sensor surface was characterized using voltammetry. The assay specificity was demonstrated using interfering species and exhibited high specificity toward the target protein. The aptasensor showed a wide dynamic range, 10 pg/mL−100 ng/mL in buffer, with a 1.15 pg/mL limit of detection. The sensor also has a linear response to KIT spiked in human serum and successfully detected KIT in cancer-cell-conditioned media. The proposed aptasensor has applications as a continuous or intermittent approach for cancer therapy monitoring and diagnostics (theranostics).

Bicarbonate insertion triggered self-assembly of chiral octa-gold nanoclusters into helical superstructures in the crystalline state

“…However, up to date, cluster-based helical architectures have been 50 rarely reported due to the lack of structural stability and difficulty in atomic-leveled characterizations. [23][24][25][26][27] Thus, the in-depth investigation on the helical superstructures of ordered arrangement units at atomic level is still in the hysteretic state. Protective ligands on the surface of coinage metal nanoclusters 55 are especially crucial in dominating the sizes, structural patterns and physicochemical properties, moreover, appropriate choice of surface ligands is directly correlated to their packing in crystalline state, [28][29][30][31][32][33][34] which may result in diverse superstructures.…”

“…However, to date, cluster-based helical architectures have been rarely reported due to the lack of structural stability and difficulty in atomic-level characterization. [23][24][25][26][27] Thus, in-depth investigation of helical superstructures of ordered arrangement units at the atomic level is still in the hysteretic state.…”

A compact, low-cost, and binary sensing (BiSense) platform for noise-free and self-validated impedimetric detection of COVID-19 infected patients

“…Label-free, accurate, quantitative, and low-cost electrochemical immuno-biosensors are one of the most promising approaches for accurate, rapid, and quantitative detection of various bodily fluid proteins, cytokines, and hormones. These biosensors have been used for the early diagnosis of several diseases, such as brain injuries ( Khetani et al 2018 , 2021 ), cancer ( Akhavan et al, 2014 ; Chung et al, 2021 ; Pimalai et al, 2021 ), infectious diseases ( Idili et al, 2021 ; Wu et al, 2018 ), and other clinical and pharmaceutical applications ( Arduini et al, 2016 ; Castle et al, 2021 ; El Harrad et al, 2018 ; Monošík et al, 2012 ). For complex bodily fluids such as the blood, the matrix effect has been a critical challenge for the reliable detection of several biomarkers for which multiplex biosensors with the capability of detecting matrix effect are highly beneficial ( Gao et al, 2017 ; Liu et al, 2021 ; Salahandish et al, 2022a ; Timilsina et al, 2021 ; Zupančič et al, 2021 ).…”

Cortisol Detection in Undiluted Human Serum Using a Sensitive Electrochemical Structure-Switching Aptamer over an Antifouling Nanocomposite Layer

“…Recently, electrochemical-based assays have gained popularity due to their low cost, high sensitivity, and high level of integration, especially in portable form factors. − While most electrochemical techniques use an assay similar to ELISAs, a new format using affinity reagents with conformation-changing properties is appealing since the electroactive reporter can be directly conjugated to the probe molecule, removing the need for a second recognition element. − Aptamers are single-stranded oligonucleotides developed through systemic evaluation of ligand by exponential enrichment process (SELEX) with a high affinity toward the target molecule . They have advantages in terms of stability, cost, shelf-life, and ease of chemical modifications compared to traditional antibody-based systems. , Furthermore, aptamers can be engineered to have a conformation-switching property that allows them to modulate the label’s position during a binding event when labeled with a redox-active molecule. ,, These properties make conformation-changing aptamers attractive for wash-free, reagent-less, continuous monitoring applications.…”

“…29,30 Furthermore, aptamers can be engineered to have a conformationswitching property that allows them to modulate the label's position during a binding event when labeled with a redoxactive molecule. 26,31,32 These properties make conformationchanging aptamers attractive for wash-free, reagent-less, continuous monitoring applications.…”