Organic Field Effect Transistor Chiral Sensors With Ultra-high Sensitivity Based On Cationic β-Cyclodextrin Derivatives

Chirality is one of the basic characteristic traits of nature.Enantiomers have similar structures and identical physical properties,but often exhibit different or even opposite biological,pharmacological,toxicological activities and metabolic processes in biological systems.Achieving rapid and highly sensitive chiral discrimination is always a great challenge in modern-day analytical sciences.Herein,cyclodextrin derivatives named Mono-6A-deoxy-6-（1-allylimidazolium）-per（3,5-dimethyl）-henylcarbamoylated-β-CD（Im⁺-Ph-β-CD）and Per（3,5-dimethyl）phenylcarbamoylated-β-CD（Ph-β-CD）are synthesized and employed to construct chiral sensor based on organic field-effect transistors（COFETs）with F₁₆CuPc as semiconducting layer to afford rapid chiral sensing with ultra-high sensitivity.Firstly,COFET is developed by directly assembling Im⁺-Ph-β-CD and Ph-β-CD onto the semiconductor layer as sensing units.A lowest detection concentration of 1 a Mis achieved for Phe,PA,MA and CA.The Im⁺-Ph-β-CD/COFET afforded better enantioselectivity enantioselective due to the enantioselective electrostatic interaction between the analytes and the positively charged CD in addition to the inclusion complexation.Then,COFET is developed by employing Im⁺-Ph-β-CD as both the recognition unit and a quasi gate,which induces a secondary accumulation channel of electrons in the n-type transistor to achieve the signal transduction and amplification via field effect.The charge of imidazolium group is partially shielded due to its self-inclusion in the CD cavity,and this shield effect is reduced at varying degrees in the existence of isomers due to the competitive inclusion.Consequently,the different weak intermolecular interactions related to the target-induced CD-enantiomer complexation with different geometry and stabilization energy for each isomer can be transformed to electronic signals based on the variety of Im⁺-Ph-β-CD’s effective charge rather than the intrinsic charge of analytes hence leading to chiral differentiation,and the hydrogen-bonding network of Im+-Ph-β-CD further magnify the signal.The as-prepared COFETs affords rapid and real-time discrimination to small molecule enantiomers at single molecule level with a limit of detection of 8.07×10^-19 M in a 200μL volume（about 97molecules）.This working strategy even allows chiral discrimination of electrically neutral analytes.Moreover,we prove the great potentiality of the chiral organic field effect transistor in quantitative analysis of commercial medicines.