An enhanced chemiluminescence bioplatform by confining glucose oxidase in hollow calcium carbonate particles

Enzyme-relative enhanced chemiluminescence (CL) has been receiving increased interest in various scientific fields, such as environmental monitoring, food analysis and clinical diagnosis1. CL, without the need of any excitation light source and any spectral resolving system, has many attractive advantages in low background signals, high sensitivity, wide linear range, simplicity of operation and cost-effectiveness2. Nevertheless, CL analysis has to suffer from shortcomings, such as poor selectivity because of co-existing species and relatively low emission intensity resulting from some CL reactions possessing very low efficiency in transforming chemical energy into light3. This issue can be resolved by introduction of enzyme, especially immobilized enzyme on some matrixes, such as grapheme oxide, CNT, TiO2 nanotubes and PANI microtubes4,5,6,7. Due to confine effect provided by these materials, immobilized enzyme can not only guarantee the selectivity of CL reaction but also cause the enhancement of enzymatic reactivity. Calcium carbonate (CaCO3) is not only widely recognized bone filling materials in medicine but also the most popular filler in industrial application8. CaCO3 particles have some polymorphs mainly including calcite, vaterite and aragonite. Among them, hollow structural calcium carbonate (HCC) particles exhibited amazing encapsulation capability of biomolecules and drugs because of their many beneficial properties such as high porosity, high surface area to volume ratio and biocompatibility towards biomolecules9,10,11. More importantly, their hollow structure has great potential for providing confined space to improve enzyme biocatalysis. So, understanding the enzymatic reaction kinetics occurring within the confine space of HCC particles is of interest and would provide a novel strategy to effectively and specifically amplify CL signal. Nevertheless, to our knowledge, the HCC particles have never been used for any enzyme-enhanced CL amplification. Herein, we present a facile strategy to develop a novel CL platform based on HCC/Lucigenin&GOx (HLG) film for sensitive detection of glucose in human serum samples. The CL platform was facilely prepared by adding a mixture solution of GOx and lucigenin on HCC film to get a HLG film. When glucose was incubated with the HLG film to generate H2O2, enzyme reaction kinetic parameters such as enzymatic rate constant kcat and Michaelis-Menten constant (Km) on the CL platform were studied, better than those of free GOx and the immobilized GOx on the reported grapheme oxide CL system. A high sensitivity with a LOD of 9.0 pM and good selectivity were shown. All advantages would be ascribed to the HCC platform that not only provides high ratio of surface-to-volume for better mass and energy transfer, but also gives rise of confine effect for facilitating the maintenance of bioactivity and the high affinity toward substrate of immobilized enzyme. No need of complicated assembly procedure and pretreatment of sample, the sensitive and selective CL platform would provide wide potential applications in disease diagnosis and food safety.