Supporting Information Ratiometric Detection of Intracellular Lysine and ph with One-Pot Synthesized Dual Emissive Carbon Dots Wei Song, 1 Wenxiu Duan, 2 Yinghua Liu, 1 Zhongju Ye, 3 Yonglei Chen, 1 Hongli Chen, 1 Shengda Qi, 1 Jiang Wu, 1 Dan Liu, 2 Lehui Xiao, 3, * Cuiling Ren, 1, * and Xingguo Chen 1 1 State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, People s Republic of China 2 School of Life Sciences, University of Science and Technology of China, Hefei, 230027, People s Republic of China 3 College of Chemistry, Nankai University, Tianjin, 300071, People s Republic of China *Corresponding Author E-mail: rencl@lzu.edu.cn; lehuixiao@163.com
Experimental Section Materials. o-phenylenediamine was commercially obtained from Aladdin Chemistry Co. Ltd. (Shanghai, China). Phosphoric acid was supplied by Tianjin Kaixin Chemical Industry Co. Ltd (Tianjin, China). Sodium phosphate, Sodium dihydrogen phosphate, amino acids (lysine, glycine, alanine, arginine, histidine, cysteine, threonine, and tryptophan), glutathione and metal salts (CdCl 2, FeCl 2, FeCl 3, HgCl 2, MnCl 2, CuCl 2 and ZnCl 2 ) were all purchased from Tianjin Guangfu Chemical Reagents Co. Ltd. (Tianjin, China). 1, 5-diaminopentane, 6-aminocaproic acid and DL-norleucine were purchased from Alfa Aesar. Ultrapure water was used throughout the experiments. Instruments and Apparatus. The morphology and sizes of the prepared dual emission carbon dots were acquired on a Hitachi-600 transmission electron microscope (TEM, Hitachi, Japan). Powder X-ray diffraction (XRD) pattern were obtained by a D/max 82400 X-ray powder diffractometer (Rigaku, Japan) as incident radiation with CuKa (λ=0.154056 Å). Fourier transform infrared spectroscopy (FT-IR) was recorded using a Nicolet Nexus 670 spectrometer using KBr pellets, scanned in the range of 4000 to 500 cm 1 at room temperature. X-ray photoelectron spectroscopy (XPS) measurement was conducted on a PHI-5702 spectrometer equipped with an Al Kα exciting source. The ultraviolet visible (UV vis) absorption spectra were conducted on a TU-1901 double beam UV-vis spectrophotometer (Beijing Purkinje General Instrument Co., Ltd., Beijing, China). All fluorescence spectra were performed on a RF-5301
spectrofluorophotometer equipped with a Xe lamp under ambient conditions (Shimadzu, Kyoto, Japan). Time-resolved fluorospectroscopy was carried out on a time correlated-single-photo-counting (TCSPC) system from FL 920 spectrometer with λ ex =560 nm. Fluorescent photographs were taken using a Nikon camera under sun light and UV lamp (365 nm). The cellular imaging was acquired on a Nikon Ti inverted microscope with a spinning disk confocal (Yokogawa). MTT Assay. The cell viability assessment was carried out using the MTT assay. Typically, 100 μl of cells were seeded in a 96-well plate with a density of 5 10 5 cells per ml and allowed to adhere overnight. After incubation with dcds for 10 h at 37 in a humidified atmosphere with 5% CO 2, 10 μl of MTT (5 mg ml 1 ) was added to each well. After incubating for another 4 h at 37, the media were removed, and 100 μl DMSO was added to each well and shaken for 2 min. Finally, the absorbance was measured at 490 nm using a microplate reader (Tecan). The cell viability was defined as the ratio of the absorbance in the presence of dcds (sample) to that in the absence of dcds (control). Cell viability = I sample /I control.
Figures, Tables. Figure S1. XPS survey spectra for dcds. Figure S2. FL spectra (a) and UV-vis spectra (b) of CDs prepared by opd with different reagents: sulphuric acid (blue line), citric acid (green line), sodium phosphate (red line) and ammonium phosphate (black line). FL spectra (c) and UV-vis spectra (d) of CDs prepared by m-phenylenediamine (red line) and p-phenylenediamine (black line) with phosphoric acid. Figure S3. The linear relationship between F 440 /F 624 or F 440 and the concentration of lysine at different ph (C dcds =2.8 μg/ml). Figure S4. Time course response of dcds to lysine at 440 and 624 nm, respectively. (C dcds =2.8 μg/ml, ph=2.0). Figure S5. (a) FL spectra of dcds in the absence and present of lysine. TEM images of dcds before (b) and after (c) the addition of lysine. (d) FTIR and (e) UV-vis spectra of dcds in the absence and present of lysine. Figure S6. FL spectra of dcds and their mixture with lysine, 1, 5-diaminopentane, 6-aminocaproic acid and DL-norleucine (concentrations were all 260 μm). Figure S7. (a) FL intensity variation at 624 and 440 nm and (b) FTIR spectra of the dcds under different ph conditions. Figure S8. Cell viability of HeLa cells treated with different concentrations of dcds. Figure S9. FL intensity variation of the prepared dcds under different (a) ion strength, (b) temperature and (c) irradiation time (λ ex =380 nm). Figure S10. Fluorescence images of HeLa cells treated with dcds in blue channel, red channel and merged image of blue and red channel. Scale bar is 10 μm. Table S1. Detection performance of dcds towards lysine at different ph. Table S2. Detection results of lysine by dcds in human serum. Table S3. Zeta-potential of dcds at different conditions.
Figure S1. XPS survey spectra for dcds.
Figure S2. FL spectra (a) and UV-vis spectra (b) of CDs prepared by opd with different reagents: sulphuric acid (blue line), citric acid (green line), sodium phosphate (red line) and ammonium phosphate (black line). FL spectra (c) and UV-vis spectra (d) of CDs prepared by m-phenylenediamine (red line) and p-phenylenediamine (black line) with phosphoric acid.
Figure S3. The linear relationship between F 440 /F 624 or F 440 and the concentration of lysine at different ph (C dcds =2.8 μg/ml).
Figure S4. Time course response of dcds to lysine at 440 and 624 nm, respectively. (C dcds =2.8 μg/ml, ph=2.0).
Figure S5. (a) FL spectra of dcds in the absence and presence of lysine. TEM images of dcds before (b) and after (c) the addition of lysine. (d) FTIR and (e) UV-vis spectra of dcds in the absence and present of lysine.
Figure S6. FL spectra of dcds and their mixture with lysine, 1, 5-diaminopentane, 6-aminocaproic acid and DL-norleucine (concentrations were all 260 μm).
Figure S7. (a) FL intensity variation at 624 and 440 nm and (b) FTIR spectra of the dcds under different ph conditions.
Figure S8. Cell viability of HeLa cells treated with different concentrations of dcds.
Figure S9. FL intensity variation of the prepared dcds under different (a) ion strength, (b) temperature and (c) irradiation time (λ ex =380 nm).
Figure S10. Fluorescence images of HeLa cells treated with dcds in blue channel, red channel and merged image of blue and red channel. Scale bar is 10 μm.
Table S1. Detection performance of dcds towards lysine at different ph. ph line range (μm) detection limit (μm) 1.5 0.5-170 0.110 2.0 0.5 260 0.094 3.0 1.0-170 0.190 5.0 0.5-150 0.120 7.4 1.0-170 0.200
Table S2. Detection results of lysine by dcds in human serum. Sample Detected (μм) Added (μм) Found (μм) RSD (%, n=3) Recovery (%) 5.00 9.03 0.99 103.2 Serum 3.99 50.00 54.43 0.43 100.6 100.00 101.9 0.50 97.9
Table S3. Zeta-potential of dcds at different conditions. Sample Zeta potential (mv) ph=2.0 4.23 ph=2.0+ lysine (260 μm) 1.37 ph=5.0-1.64 ph=8.0-5.78