Chiral detection using reusable fluorescent amylose-functionalized graphene

By using DNA or a peptide as a common probe, graphene-based biosensing has made significant progress. However, to the best of our knowledge, a graphene-based chiral sensor has not been reported. Chiroselective recognition is perhaps the most subtle to achieve because of the similarity of the optical enantiomers. Therefore, besides using DNA or peptides as probes, developing graphene-based sensors with chiral selectivity is highly desirable. Here a reusable natural cheap polysaccharide, amylose-functionalized graphene was developed for highly sensitive and visual fluorescent chiral sensing. The detection sensitivity toward L-Trp is over 100-times higher than that of recently reported electrochemical sensors and colorimetric sensors. In comparison with commonly used DNA or peptides as a probe, natural amylose is more attractive because of its low cost, ready availability, simple manipulation and renewability. The specific selectivity for tryptophan (Trp) enantiomers towards other essential amino acids allows potential chiroselective analysis of Trp in complex samples such as biological fluids. This design can, in principle, be implemented for other slender target molecules that can form an inclusion complex with amylose.