Facile Synthesis of Fluorescent Carboxymethyl Cellulose Polymer Dots and Multi-Purpose Applications in Ph and Glucose Sensing

Herein, fluorescent carboxymethyl cellulose polymer dots (B-PDs) were synthesized by a straightforward route under mild conditions using ethylenediamine-modified carboxymethyl cellulose (CMC-NH2) and phenylboronic acid as precursors. The B-PDs exhibit a uniform nanoscale size distribution, good water solubility, photostability and excellent fluorescence emission with a high fluorescence quantum yield of 21.6 %. The B-PDs display a reversible fluorescence response with blue emission in acidic solution and green emission in alkaline solution. Moreover, the B-PDs can be designed as an excellent fluorescent sensor for glucose detection. After the addition of glucose, the FL intensity at lambda ex = 388 nm can be enhanced due to the assembly of glucose on the B-PDs based on the reversible reaction between boronic acid and cis-diols through the aggregation-induced enhancement effect (AIE). Two good linear relationships can be obtained between (F-F0)/F0 and the glucose amount ranging from 0 -0.005 M (R2 = 0.9971) and 0.01 -1.2 M (R2 = 0.9984), and the detection limit (LOD) was calculated to be 52 mu M (3a/slope). Meanwhile, the proposed probe was successfully utilized to analyze glucose in human urine samples (recovery: 97.9-104.1 %, RSD: 2.64-4.23 %) by the standard addition method, indicating good feasibility as a practical platform for sensing.