Highly stable colorimetric aptamer sensors for detection of ochratoxin A through optimizing the sequence with the covalent conjugation of hemin

Abstract

Optimization of hairpin DNA is introduced to detect ochratoxin A (OTA) by chemically conjugating its cofactor, hemin, toward the 5'-end. The newly designed OTA aptasensor showed enhanced stability and sensitivity, thereby lowering the detection limit to an ~1 nM level. Furthermore, an optimal spacer for hemin conjugation was investigated for stable responses toward very diluted OTA solutions.

Gold nanoparticles enhanced SERS aptasensor for the simultaneous detection of Salmonella typhimurium and Staphylococcus aureus

“…Several characteristics of aptamers make them attractive for pre-analytical sample processing and biodiagnostic assay development, including their small size, ease of synthesis and labeling, lack of immunogenicity, low cost of production and target binding affinity and specificity (Ahmadi et al, 2014;Jo et al, 2011). Biosensors that use an aptamer as a specific recognition part known as an aptasensor have become an area of research interest (Tombelli et al, 2005;Suh et al, 2014;Kim et al, 2014;Guo et al, 2014;Lee et al, 2014).…”

Design and optimization of an ultra-sensitive hairpin DNA aptasensor for Salmonella detection

“…In order to tackle this problem, hemin was covalently conjugated to the 5 0 -end of the SHD strand, as in our previous study, which enhanced the stability of G-quadruplex formation without requiring an excessive dose of hemin. 19 Since the hemin conjugation lowers DG EAD2 , DG SHD should be further lower relative to DG EAD2 to prevent the premature loosening of the hairpin. Therefore, SHD 2 ð DG…”

DNA for Non-nucleic Acid Sensing

“…This approach has been widely used for the detection of ochratoxin A (Lee et al 2014), ATP ) and thrombin (Yuan et al 2011). For thrombin, nanoparticles functionalized both by the aptamer sequence and guanine-rich sequences (Yuan et al 2012) were used in the transduction scheme.…”