Construction of hierarchical porous 3D nanostructures with high specificity as SERS aptasensors for rapid and ultrasensitive detection of MC-LR

Author：Qian Xie a,1 , Jinxin Chi a,1 , Zhixin Li b , Xucong Lin b , Guihua Huang a,*

ABSTRACT：The construction of plasmonic nanostructures is a frontier research area in the field of Surface enhanced Raman scattering (SERS). Three-dimensional (3D) porous materials coupled with aptamers have attracted increasing attention for application in SERS sensing, owing to their great promise towards offering both high specific and ultrasensitive detection capacity. However, most of these SERS sensors are plane-shaped or solution-based, which makes target molecules with a reduced mass transfer, thus leading to a relatively poor capture efficiency. Herein, we demonstrate a capillary-based porous nanostructure coupled with aptamers that can serve as a type of SERS aptasensor for rapid trace detection. The aptasensor was prepared by immobilization of aptamer-modified SERS nanotags on a porous silica monolith which was obtained by an in-situ polymerization in a capillary with a facile fabrication process. The 3D porous silica monolith (3D-PSM) with a hierarchical biporous structure that could enable the rapid permeation of the aqueous phase and provide high specific surface area and active sites, endows the material with high capture efficiency of target molecules. Besides, according to the size of aptamers, stable and uniformed hotspots of 7–8 nm in size were formed, which precisely guaranteed the sensitivity, specificity, and stability of detection. The experimental verification showed that the proposed aptasensor could detect the presence of microcystin-LR at concentrations as low as 0.01 nmol/L, with fast recognition time (10 min), low sample consumption (20 μL), and simple operation. All the results suggest that this new strategy has promising potential in rapid microvolume trace analysis in various fields.

Keywords：Surface-enhanced Raman scattering Aptasensors Porous 3D nanostructures High specific and ultrasensitive Rapid detection

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