Supporting Information Robust, Highly-visible and Facile Bioconjugation Colloidal Crystal Beads for Bioassay Panmiao Liu, Tao Sheng, Zhuoying Xie,,,* Jialun Chen and Zhongze Gu,,* State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China, 210096 National Demonstration Center for Experimental Biomedical Engineering Education, Southeast University, Nanjing, China, 210096 * Corresponding author: zyxie@seu.edu.cn; gu@seu.edu.cn S-1
Figure S1. Raman spectra of PDA@SiO 2 CPC beads and SiO 2 CPC beads. Figure S2. (a) Magnified FESEM image of PDA@SiO 2 particles with 7 nm thickness PDA shell. (b) FESEM image of the cross section of PDA@SiO 2 CPC beads. S-2
Figure S3. FESEM images of PDA@SiO 2 nanoparticles with 204 nm, 231 nm and 275 nm from left to right and the insert scale bar is 200 nm. S4. Color theory and calculation of three tristimulus values Color is a perception of the human eye vision system to light. The CIE 1931 color spaces were the first defined quantitative links between physical pure colors in the electromagnetic visible spectrum, and physiological perceived colors in human color vision. The mathematical relationships that define these color spaces are essential tools for color management. For colored measurement, electromagnetic visible spectrum was defaulted to absolute reflection spectra, obtained with the calibration standard whiteboard as completely diffuse reflector. Absolute reflectance is a bridge of the visual color to the color data, socalled tristimulus values (CIE XYZ), calculated by the CIE's color matching functions. Tristimulus values (CIE XYZ) are the three parameters that correspond to the levels of stimulus of three types of cone cells in the retina of the human eyes to the light of certain wavelengths in the visible region, which peaks at approximately 430 nm, 540 nm, and 570 nm. The CIE XYZ color space is deliberately designed that the Y parameter is a measure of the luminance of a color. The chromaticity of a color is then specified by the two derived parameters x and y, two of the three normalized values being functions of all three tristimulus values X, Y, and Z. The derived color space specified by x, y, and Y is known as the CIE xyy color space and is widely used to specify colors in practice. All color sensations are in principle endowed with inherent tristimulus values (CIE XYZ), which could be used for the evaluation of three attributes of color: hue, luminance and saturation. Among them, hue presents the appearance of a color and is represented by the dominant wavelength in the CIE xyy color space. Dominant wavelength is wavelength of spectral trajectory sited on the intersection point of chromaticity parameter (x, y) of this color with the spectral trajectory. Luminance of a color specifies the lightness of the color. In the CIE xyy color space, Y parameter is a measure of this attribute. Saturation denotes the purity of a color. In the CIE xyy color space, the quantitative value to specify this property is calculated as follows: In the formula, X, Y and Z are the three tristimulus values of this color and Xλ, Yλ and Zλ are the tristimulus values of the corresponding dominant wavelength sited in the spectral trajectory. S-3
Figure S4. Photograph (a), reflection spectrum(b), absolute reflectance spectrum(c) and 1931 CIE coordinates (d) of the PDA@SiO 2 CPC beads and SiO 2 CPC beads. S-4
Figure S5. (a) Schematic of compression test of PDA@SiO 2 CPC beads. (b) optical image before and after compression on the NanoTest system, the insert scale bar is 100 µm. Figure S6. Typical load vs depth curve analysis showing the compression (breaking) of the CPC beads. S-5
Figure S7. (a) Fluorescence image of human anti-goat IgG immobilized PDA@SiO 2 CPC beads graft FITC-tagged goat-anti-human IgG, the scale bar is 200 µm. (b) Fluorescence image of BSA completely sealed PDA@SiO 2 CPC beads graft FITC-tagged goat-anti-human IgG (the white circle is the position of beads), the scale bar is 200 µm. (c) Schematic of human anti-goat IgG immobilized PDA@SiO 2 CPC beads graft FITC-tagged goat-anti-human IgG. (d) Schematic of BSA sealed PDA@SiO 2 CPC beads graft FITC-tagged goat-antihuman IgG. S-6
Figure S8. Fluorescence resulted images at different AFP concentration using PDA@SiO 2 CPC beads as carrier. Figure S9. Fluorescence resulted images at different CEA concentration using PDA@SiO 2 CPC beads as carrier. S-7
Figure S10. Fluorescence resulted images at different PSA concentration using PDA@SiO 2 CPC beads as carrier. Figure S11. Averaged fluorescence intensity of AFP, CEA and PSA from three practical clinical serum. The number of replicates at any concentration and sample was five. Error bars represent standard deviation. S-8