Harnessing a Nanostructured Fluorescence Energy Transfer Sensor for Quick Detection of Extremely Small Amounts of Glucose

Abstract

Fluorescence technique is one of the major solutions for achieving the continuous and noninvasive glucose sensor for diabetes. In this article, a highly sensitive nanostructured sensor is developed to detect extremely small amounts of aqueous glucose by applying fluorescence energy transfer (FRET). A one-pot method is applied to produce the dextran-fluorescein isothiocyanate (FITC)-conjugating mesoporous silica nanoparticles (MSNs), which afterward interact with the tetramethylrhodamine isothiocyanate (TRITC)-labeled concanavalin A (Con A) to form the FRET nanoparticles (FITC-dextran-Con A-TRITC@MSNs). The nanostructured glucose sensor is then formed via the self-assembly of the FRET nanoparticles on a transparent, flexible, and biocompatible substrate, e.g., poly(dimethylsiloxane). Our results indicate the diameter of the MSNs is 60 ± 5 nm. The difference in the images before and after adding 20 μl of glucose (0.10 mmol/liter) on the FRET sensor can be detected in less than 2 min by the laser confocal laser scanning microscope. The correlation between the ratio of fluorescence intensity, I(donor)/I(acceptor), of the FRET sensor and the concentration of aqueous glucose in the range of 0.04-4 mmol/liter has been investigated; a linear relationship is found. Furthermore, the durability of the nanostructured FRET sensor is evaluated for 5 days. In addition, the recorded images can be converted to digital images by obtaining the pixels from the resulting matrix using Matlab image processing functions. We have also studied the in vitro cytotoxicity of the device. The nanostructured FRET sensor may provide an alternative method to help patients manage the disease continuously.

Fluorescence Sensing Technologies for Ophthalmic Diagnosis

“…One highly sensitive nanostructured fluorescent biosensor was fabricated by utilizing FRET to monitor tear glucose levels ( Figure 5 a). 127 In this work, the interaction between the selected nanoparticles FITC-dextran-silica and tetramethyl rhodamine isothiocyanate-labeled Concanavalin A (TRITC-Con A) occurred through binding Con A to dextran molecules. The FRET pairs were then formed by fluorescein isothiocyanate and tetramethyl rhodamine isothiocyanate (FITC-TRITC).…”

“…Moreover, the chip can still be functionalized within 5 days. 127 The obtained fluorescence image was finally converted into readable data with the aid of MATLAB coding. Different concentrations of glucose were evaluated, and the image and data of glucose under 0.05 mmol L –1 in Figure 5 d(i) and 0.10 mmol L –1 in Figure 5 d(ii) were the corresponding results, respectively.…”

“…(d) Image of the FRET sensor and its conversion of readable MATLAB data under the glucose concentration of (i) 0.05 and (ii) 0.10 mmol L –1 , respectively. Reproduced with permission from ref ( 127 ). Copyright 2013, SAGE.…”

Fluorescent Nanobiosensors for Sensing Glucose

“…A highly sensitive nanostructured fluorescent biosensor was developed [ 108 , 109 ]. The fluorescent nanobiosensors sensing mechanism is illustrated in Figure 9 .…”

“… Steps for producing the nanostructured fluorescence resonance energy transfer nanobiosensor for monitoring tear glucose. Reprinted with permission from Reference [ 108 ]. Copyright © [2013] (Jin Zhang).…”