Construction of optical glucose nanobiosensor with high sensitivity and selectivity at physiological pH on the basis of organic–inorganic hybrid microgels

A Fluorescent Responsive Hybrid Nanogel for Closed-Loop Control of Glucose

“…The reversible glucose-responsive volume change of the gel can modify the physicochemical environment of the embedded ZnO QDs and thus convert the disruptions in homeostasis of glucose level into highly reproducible fluorescent signals (Figures 7 and 8), providing optical readout of the glucose level in blood samples. In comparison with our previously studied hybrid nanogels with the QDs/NPs physically restricted in the polymer networks, [10][11][12] the ZnO@poly(NIPAMAAm-FPBA) hybrid nanogels with ZnO QDs covalently bonding to the gel network chains demonstrate a much higher sensitivity of PL response, possibly due to the rapid and sensitive transmission of the elastic tension directly from the polymer chains to the covalently bonded QDs. The rapid and highly accurate PL response of the sensor is necessary for future in situ studies in biosystems.…”

“…Afterward, the FPBA moieties were coupled to form ZnO@poly(NIPAM-AAm-FPBA) hybrid nanogels using our previously reported procedure. 10,11 First, 0.231 g of FPBA and 0.230 g of EDC were dissolved in 35 ml water. After being cooled in an ice bath, 20 ml purified ZnO@ poly(NIPAM-AAm-AA) hybrid nanogels were added to the solution.…”

“…5,6 Our group and other groups have predominantly improved the response speed by downsizing the glucoseresponsive hydrogels into submicron and even nanogels. [7][8][9][10][11][12][13] In contrast to bulk hydrogels, the microgels/nanogels can be dispersed in water while preserving a highly stable structure. Moreover, with the inorganic quantum dots (QDs) or nanoparticles (NPs) being physically restricted in the polymer networks, the obtained inorganic-polymer hybrid microgels/nanogels could optically read out the glucose concentrations in aqueous solutions.…”

“…The glucose-responsive nanogel can modify the physicochemical environment of the embedded QDs, [10][11][12]17 converting the disruptions in homeostasis of glucose level into optical signals (Figures 7A and 7B). In comparison with the glucose-induced swelling curve (Figure 5A), the quenched PL intensity (100 -100 × I [Glucose] / I 0 mg/dl ) reveals nearly the same trend toward the glucose concentration change (Figure 7C), clearly correlating the glucose-responsive volume change of the nanogel to the PL response of the ZnO QDs immobilized in the nanogel.…”

“…Moreover, with the inorganic quantum dots (QDs) or nanoparticles (NPs) being physically restricted in the polymer networks, the obtained inorganic-polymer hybrid microgels/nanogels could optically read out the glucose concentrations in aqueous solutions. [10][11][12] The goal of this study is to develop a new class of inorganicpolymer hybrid nanogels comprising fluorescent zinc oxide (ZnO) QDs covalently bonding to boronate-derived nanogel network chains of poly[N-iso-propyl-acrylamide (NIPAM)-co-acrylamide (AAm)-co-2-acrylamidomethyl-5-fluorophenylboronic acid (FPBA)] as the glucose recognition element. The newly designed hybrid nanogels are expected to possess improved sensitivity and selectivity for glucose sensing in blood samples.…”