Electrochemical Aptasensor of Cardiac Troponin I for the Early Diagnosis of Acute Myocardial Infarction

Abstract

Cardiac troponin I (cTnI) is well-known as a promising biomarker for the early diagnosis of acute myocardial infarction (AMI). In this work, single-stranded DNA aptamers against cTnI were identified by the Systematic Evolution of Ligands by Exponential enrichment (SELEX) method. The aptamer candidates exhibited a high selectivity and sensitivity toward both cTnI and the cardiac Troponin complex. The binding affinities of each aptamer were evaluated based on their dissociation constants (Kd) by surface plasma resonance. The Tro4 aptamer that had the highest binding capacity to cTnI showed a very low Kd value (270 pM) compared with that of a cTnI antibody (20.8 nM). Furthermore, we designed a new electrochemical aptasensor based on square wave voltammetry using ferrocene-modified silica nanoparticles. The developed aptasensor demonstrated an excellent analytical performance for cTnI with a wide linear range of 1-10 000 pM in a buffer and a detection limit of 1.0 pM (24 pg/mL; S/N = 3), which was noticeably lower than the cutoff values (70-400 pg/mL). The specificity of the aptamers was also examined using nontarget proteins, demonstrating that the proposed sensor responded to only cTnI. In addition, cTnI was successfully detected in a human serum albumin solution. On the basis of the calibration curve that was constructed, the concentrations of cTnI in a solution supplemented with human serum were effectively measured. The calculated values correlated well with the actual concentrations of cTnI. It is anticipated that the highly sensitive and selective aptasensor for cTnI could be readily applicable for the accurate diagnosis of AMI.

Highly Sensitive Electrochemiluminescence Assay for Cardiac Troponin I and Adenosine Triphosphate by using Supersandwich Amplification and Bifunctional Aptamer

“…The cTnI binding aptamer was designed according to Jo et al, which can selectively bind to cTnI with a low dissociation constant at 270 pM. [23] The ATP binding aptamer was designed according to Huizenga et al, which can highly specifically bind with ATP. [24] Two auxiliary ss-DNA probes were used as linker DNAs without signal label.…”

Immunoassay for troponin I using a glassy carbon electrode modified with a hybrid film consisting of graphene and multiwalled carbon nanotubes and decorated with platinum nanoparticles

“…This sensitivity of the bioelectrode is significantly high, which is about 1.8 time more than the recently reported sensitivity of the PtNP modified graphene based bioelectrode for cTnI detection [38] over a wide linear detection range of cTnI. This signifies the importance of the 3-Dimentional G-MWCNT over the 2D pristine graphene matrix with respect to a large electroactive surface area, which provided a comparatively large amount of PtNP deposition for site specific protein immobilization with a better probe orientation, showing a much wider linear detection range for cTnI than the earlier reported bioelectrodes [21,25,[39][40][41][42][43] (Table 3). Reproducibility, specificity and stability of the assay…”

Peptide-based antifouling aptasensor for cardiac troponin I detection by surface plasmon resonance applied in medium sized Myocardial Infarction

“…MgCl 2 was purchased from Macklin Biochemical Co. Ltd. (Shanghai, China). The cTnI-binding aptamers terminate d with a biotin group, 5'-biotin-CGTGCAGTACGCCAACCTTTCTCATGCGCT GCCCCTCTTA-3' [39], the zwitt erionic peptides ( sequence: EKEKEKE-PPPPC, purity > 95%) and the zwitterion ic peptides with a terminal biotin (s equence: N'-biotin-EKEKEKE-PPP PC, purity > 95 %) were synthesized by Sangon Biotech Co., Ltd. (Shanghai, China). Absolute ethyl alcohol and sodium chloride (NaCl) were purchased from Beijing Chemical Works (Beijing, China).…”