Phenylboronic acid derivative-modified (6,5) single-wall carbon nanotube probes for detecting glucose and hydrogen...

In this paper, we presented a new method for constructing near-infrared fluorescence probes and their applications in detecting glucose and hydrogen peroxide (H₂O₂). We used purified (6,5) single-wall carbon nanotubes (SWCNTs) separated by a polyethylene glycol/dextran aqueous two-phase system as the basis for near-infrared probes. Different phenylboronic acids were used for non-covalent modification of SWCNTs (6,5). Glucose was detected by the specific binding of the boronic acid group with cis-diol. Hydrogen peroxide was detected by horseradish peroxidase (HRP) combined with phenylboronic-acid-modified SWCNTs. The results revealed that the fluorescence intensity of purified SWCNTs was significantly enhanced without other chiral nanotube interactions compared to that of the raw SWCNT material. The fluorescence responses of 3-carboxy-5-nitrophenylboronic acid-modified purified CNTs could be used to effectively measure glucose in the concentration range from 0.01 mM to 0.50 mM with an interval linear index of R ² = 0.996 (LOD = 1.7 μM, S/N = 3). The detected H₂O₂ with the 3-aminobenzeneboronic acid-modified (6,5) SWCNT with HRP was in the concentration range from 5.0 μM to 40 μM with an interval linear index of R ² = 0.997 (LOD = 0.85 μM, S/N = 3). Moreover, this sensor exhibited a strong anti-interference effect without biological matrix fluorescence effects above 1000 nm wavelength. Thus, the proposed novel near-infrared fluorescence probes employed for reducing the interference of the biomatrix in this region are expected to be used in subsequent biosensor investigations.