Polarimetric Detection of Enantioselective Adsorption by Chiral Au Nanoparticles – Effects of Temperature, Wavelength and Size

Rand S-propylene oxide (PO) have been shown to interact enantiospecifically with the chiral surfaces of Au nanopar‐ ticles (NPs) modified with Dor L-cysteine (cys). This enantiospecific interaction has been detected using optical polarimetry measurements made on solutions of the Dor L-cys modified Au (cys/Au) NPs during addition of racemic PO. The selective adsorption of one enantiomer of the PO onto the cys/Au NP surfaces results in a net rotation of light during addition of the racemic PO to the solution. In order to optimize the conditions used for making these measurements and to quantify enantiospecific adsorption onto chiral NPs, this work has measured the effect of temperature, wavelength and Au NP size on optical rotation by solutions containing Dor L-cys/Au NPs and racemic PO. Increasing temperature, decreasing wave‐ length and decreasing NP size result in larger optical rotations.