Color-tunable luminescent macrofibers based on CdTe QDs-loaded bacterial cellulose nanofibers for pH and glucose sensing

The incorporation of quantum dots into the nanoscale host matrices and assembly of fluorescent building blocks with well-organized structure are critical for the preparation of highly sensitive sensor device. Color-tunable luminescent macrofibers were obtained using wet spinning by assembling CdTe-loaded bacterial cellulose (BC) nanofibers onto one-dimensional structure. BC nanofibers are able to integrate luminescent properties of CdTe quantum dots (QDs) and extend their advantages to fiber-based structures. The luminescent macrofibers with green, yellow and orange fluorescence could be tuned easily by controlling the size of CdTe QDs. This luminescent material with moderate oriented nanofibers was used to detect pH and glucose. The resulting macrofibers exhibited a sigmoidal dependence with pH and high sensitivity to glucose concentrations. The detection limit of glucose is 0.026 mM, and the response range and sensitivity of the enzyme-modified macrofibers can be regulated through changing the reaction time which is suitable for different situations. Furthermore, the assay did not require addition of external reagents because all components were deposited onto the fiber substrate. The comparison with commercialized glucose meter indicated that this system is reliable and suitable for practical application. The paper would provide a new platform for the fabrication of fiber-based biosensor based on BC nanofibers, possessing great potential for the development of flexible and wearable biosensing devices. (C) 2017 Elsevier B.V. All rights reserved.