Ultrasensitive Enantioselective Chiroptical Sensing with Large-Area Twisted Aligned Carbon Nanotube Films

Abstract Enantioselective chiroptical sensing is gaining traction across various applications. However, intrinsic molecular chiroptical responses are weak, and existing amplification approaches add synthesis, manufacturing, or operational complexity that limits sensitivity and scalability. Here, we present an enantioselective sensing paradigm merging adsorption-driven chirality induction with large-scale optical transduction in twisted stacks of aligned carbon nanotube (CNT) films. Chiral molecules adsorb onto CNTs to form chiroptically active composites that are macroscopically assembled by alignment and rotational stacking, yielding large ultraviolet circular dichroism (CD). We resolve enantiomer handedness and quantify concentration in single-enantiomer aqueous solutions using a single sensor without lithography, hotspot delivery, or a paired opposite-handed reference. We achieve high sensitivity with estimated sub-μM minimum detectable concentrations for glucose and provide a proof-of-concept demonstration with alanine. Neither analyte-only solution shows detectable CD under the present measurement conditions. We demonstrate Langmuir-type adsorption behavior using molecular dynamics simulations and reproduce experimental results using optical simulations. This platform provides a foundation for future development toward cost-effective in situ enantiomer monitoring in aqueous environments.