Single-molecule force spectroscopic study on chiral recognition of cysteine derivatives immobilized on a gold substrate by using AFM tips chemically modified with optically active crown ethers

The chiral recognition of cysteine derivatives immobilized on a gold substrate using atomic force microscopy (AFM) tips chemically modified with optically active crown ethers was quantitatively investigated with single-molecule force spectroscopy (SMFS). Interestingly, the chiral recognition ability of the optically active crown ether-modified tip was entirely opposite to that of its optical isomer-modified tip. The difference of rupture forces for the chiral recognition was determined to be about 40 pN under our experimental conditions.