The Corona Phase Molecular Recognition (CoPhMoRe) method employs fluorescent semiconducting single-wall carbon nanotubes (SWCNTs) wrapped with heteropolymers composed of hydrophobic and hydrophilic groups, thereby creating binding sites on the surface for specific analytes. A heteropolymer corona phase of SWCNTs has been used for the recognition of insulin. In this study, we extend CoPhMoRe to enable ratiometric sensing of analytes such as insulin by incorporating quantum defects into the pristine structure of fluorescent SWCNTs. This modification results in the emergence of a new emission feature alongside the intrinsic E11 emission. To achieve this, covalent modification of SWCNTs wrapped with the polymer was performed to create sp³ defects within the sp² hybridized carbon atom network of the SWCNTs. Additionally, we scaled up a method for the isolation of single-chirality SWCNTs, which enhances the efficacy of CoPhMoRe by simplifying the fluorescence characterization of the sensor. Using sorted SWCNTs for making insulin sensors enhances sensor response to insulin by 30% compared to the sensors made up of unsorted SWCNTs. The use of sorted SWCNTs also significantly improves the fabrication of ratiometric insulin sensors by enabling precise modulation of the ratio between new emission feature and E11 ratio. To quantify the ratiometric sensor response, a new set of metrics is introduced, including the wavelength shift and intensity of the new emission feature and E11 emission, along with their ratio. Based on these metrics, our findings suggest that a minimum ratio of 3 between new emission feature and E11 emission is recommended for the transformation of a standard nanosensor into a ratiometric nanosensor via the incorporation of quantum defects into the pristine structure of a single-chirality SWCNT.
