Facile synthesis of fluorescent carboxymethyl cellulose polymer dots and multi-purpose applications in pH and glucose sensing

Abstract

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 λex = 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 μM (3σ/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.