Preparation of photoluminescent enzymatic nanosensors for glucose sensing

Significance Statement

Diabetes mellitus is a worldwide problem because many people are diseased. Its main characteristic the glucose level, is chronically raised. Rigorous controlling of glucose level can decelerate long-term complications such as microangiopathy, kidney or nerve damages which are attributed to diabetes. Hence, numerous sensors were developed for fast monitoring of glucose levels in physiological fluids.

In the present work, a simple and steady fluorescent nanoparticle NPs-GOx was prepared by coupling GOx to nanoparticle doped with two fluorescence dyes for detecting glucose. The ensembles comprises oxygen sensitived ratiometric fluorescence nanoparticles (NPs) and glucose oxidase (GOx), which can be used as glucose biosensor for its quantitative analysis. The large surface area of these nanoparticles resulted in a high enzyme loading. Specifically, NPs are prepared by a one-step reprecipitation-encapsulation method for sensing dissolved oxygen. To endow the NPs with glucose-detecting capability, GOx was successfully immobilized onto the surface of PLL shell via a glutaraldehyde-mediated Schiff-base reaction. Thus, the nanoprobe NPs-GOx for glucose detecting is successfully constructed. The nanoprobe possess excellent fluorescence emission (at 520nm and 650nm) and high stability. Glucose calibration was performed with ratiometric photoluminescence and time-resolved fluorescence (TRF) respectively, and a series of calibration plots were constructed according to determination time. In comparison, the ratiometric method resulted in wide dynamic range (e.g. 2–10 mM) and high limit of detection (∼1–2 mM), while the TRF mode gave narrow dynamic range (e.g. 1–6 mM) with low detection limit (∼0.1–0.2 mM). Finally the enzymatic glucose nanosensors were tested in human serum samples with a TRF microplate reader.

Preparation of photoluminescent enzymatic nanosensors for glucose sensing. Global Medical Discovery

About the author

Prof. Hong-shang Peng received his PhD degree in Optics from Beijing Jiaotong University in 2007. After postdoctoral research in the group of Prof. Otto S. Wolfbeis at University of Regensburg (Germany) as an Alexander von Humboldt fellow, he joined the faculty of Beijing Jiaotong University in 2009. From 2013 to 2014, he visited the group of Prof. Daniel T. Chiu at the University of Washington (Seattle). In Nov. 2015, he transferred to Minzu University of China as a Professor. His research interest focused on fluorescent nanoparticles as biosensors and bio-imaging agents. 

About the author

Shao-wei Gao is a graduate student of Beijing Jiaotong University in China. She obtains her bachelor’s degree from Beijing Jiaotong University. Her research focuses on fluorescent glucose and hydrogen peroxide nanosensors. 

Journal Reference

Sensors and Actuators B: Chemical, Volume 222, January 2016, Pages 638–644. 

Shao-wei Gao1,Hong-shang Peng1, Xiao-hui Wang1,Fang-tian You1,Feng Teng1,Hong-xia Wang2

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  1. Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, PR China
  2. Department of Neurology, Zhongguancun Hospital, Beijing 100190, PR China
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Abstract

A novel photoluminescent glucose nanosensor was facilely prepared by coupling glucose oxidase (GOx) with poly-l-lysine coated oxygen nanosensors via a glutaraldehyde-mediated Schiff-base reaction. The GOx molecules residing on particle surface catalyzed glucose with the expense of oxygen, which was detected by the sensing particle core incorporated with the reference dye coumarin 6 and oxygen probe Pt(II)-meso-tetra(pentafluorophenyl)porphine. The proposed glucose nanosensors (∼150 nm in hydrodynamic diameter) had a quick response time varied from less than 2 min to 4 min. Glucose calibration was performed with ratiometric photoluminescence and time-resolved fluorescence (TRF) respectively, and a series of calibration plots were constructed according to determination time. In comparison, the ratiometric method resulted in wide dynamic range (e.g. 2–10 mM) and high limit of detection (∼1–2 mM), while the TRF mode gave narrow dynamic range (e.g. 1–6 mM) with low detection limit (∼0.1–0.2 mM). Finally the enzymatic glucose nanosensors were tested in human serum samples with a TRF microplate reader.

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