Nb2CTx MXene Integrated Tapered Microfiber Based on Light-Controlled Light for Ultra-Sensitive and Wide-Range Hemoglobin Detection

Hemoglobin is an indicator of various diseases in humans, and shows excellent photothermal properties. Here, a biosensor combining the molecular photothermal effect with the Nb
₂
CT
_x
MXene integrated microfiber is proposed for the specific detection of human hemoglobin concentration by light-controlled light technique. The Nb
₂
CT
_x
MXene with a large specific surface and hydrophilicity is deposited on the surface of the microfiber through an optical deposition method, which makes hemoglobin molecules adsorbed on the surface of the microfiber and enhance the interaction between light and matter. Under the irradiation of excitation light, the photothermal effect of the molecules amplifies the optical signal to be measured, which further improves the sensitivity and selectivity of detection. The experimental results show that the sensitivity reaches 7.581 nm/(g•dL
⁻¹
) with a limit of detection of 0.0026 g/dL, which is far below the blood hemoglobin level of humans (0–13 g/dL). It has been also confirmed that the sensor exhibits good selectivity. This method has the advantages of being resistant to electromagnetic interference, low cost, and is applicable for in-situ label-free detection, therefore, being potentially useful in the fields of disease diagnosis, food safety monitoring, and environmental pollution detection.