Label-Free Detection of Ochratoxin A Using Aptamer as Recognition Probe at Liquid Crystal-Aqueous Interface

Aqueous interfaces of stimuli-responsive, thermotropic nematic liquid crystals (LC) have been utilized in the design biosensing platforms for a range analytes. Owing to orientational changes LC, these can easily report aptamer-target binding events at LC-aqueous interface. We demonstrate label-free, simple and robust technique detection Ochratoxin A (OTA) using aptamer as recognition probe. The self-assembly CTAB (cetyltrimethylammonium bromide; cationic surfactant) aqueous-LC interface gives homeotropic orientation LC. In presence negatively charged OTA specific aptamer, forms complex with CTAB. Formation aptamer-CTAB results ordering transition LCs planar/tilted. OTA, strong stable G-quadruplex structure that redistribution leads designed LC aptasensor exhibits limit 0.1 nM. observed sensitivity was affected by pH ionic strength. addition, we demonstrated applicability tap water apple juice. This approach offers advantages over conventional methods terms fabrication, ease operation, analysis.