S-1 Supporting Information TiO2-Coated Silica Photonic Crystal Capillaries for Plasmon- Free SERS Analysis Bing Liu, †,‡,§ Kan Wang, †,‡ Bingbing Gao, ∥ Jie Lu, ⊥ Haiming Li, #, ∇ ,○ and Xiangwei Zhao *†,‡,§ † State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, ‡ National Demonstration Center for Experimental Biomedical Engineering Education, § Key Laboratory of Environmental Medicine Engineering of Ministry of Education, ⊥ School of Materials Science and Engineering, # State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210009, China ∥ School of Pharmaceutical Sciences and School of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China. ∇ School of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210003, China ○ Key Laboratory of Radar Imaging and Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China *Email: xwzhao@seu.edu.cn Table of Contents Figure S1 FDTD simulation model of the TiO2-coated silica photonic crystal capillary. Figure S2 Raman and reflection spectra of the TiO2-coated silica photonic crystal capillary. Figure S3 FDTD simulation of the photonic crystal capillary. Figure S4 Reproducibility test of five batches of the TiO2-coated photonic crystal capillary. Figure S5 Raman spectra of 10 -2 M dopamine adsorbed into the bare and TiO2- coated photonic crystal capillaries. Table S1 A comparison of dopamine detection between different methods. Table S2 Detection and recovery test of dopamine in the human urine samples.