Hybridizing aggregated gold nanoparticles with hydrogel to prepare flexible SERS chip for detecting organophosphorus pesticides Jiaxin Zhang, Xiajun Zhu, Mingming Chen, Tianwen Chen, Zhihong Liu, Jianli Huang, Fengfu Fu, Zhenyu Lin and Yongqiang Dong Abstract Surface enhanced Raman scattering (SERS) is an ultrasensitive analytic technique. However, the application of SERS in quantitative analysis usually suffers from poor reliability due to the limitations of current developed SERS substrates.