From chiral biomolecules to chiral nanocrystals: A review of the latest developments and emerging concepts

This article reviews the latest developments in the field of chiral nanocrystals (NCs), focusing primarily on plasmonic NCs. Such nanomaterials under illumination concentrate electromagnetic energy in their vicinity, enabling efficient biosensing, asymmetric photocatalysis, and light manipulation. Starting our discussion with Lord Kelvin's definition of chirality, we describe how enantiomer pairs appear when the molecule becomes progressively more complex. Making a comparison with Pasteur's chirality of molecules, we discuss nanoscale enantiomers lacking exact mirror symmetry, so-called nonexact enantiomers, and why they should appear fundamentally. Whereas chirality is an intrinsically three-dimensional (3D) concept describing perfect mirror-imaged pairs, a novel property of pseudo-chirality is handy for understanding two-dimensional (2D) systems, including the case of plasmonic growth with circularly polarized light. The topics considered in the review include bio-templated NCs, chiral bio-assemblies, transfer of chirality from biomolecules to NCs, chirality and pseudo-chirality in 3D and 2D systems, growth of NCs under circularly polarized excitation, and more.