1. Electronic Supporting Information (ESI)
Synthesis of Hybrid Nanofibers for Highly Efficient Enrichment and Detection of Phosphopeptides
Ruifang Gao†, Xiao Chen†, Chuntao Chen, Rui Shi, Fuzhong Ouyang, Jiazhi Yang, Dongping Sun*, Jian Liu*
R. Gao, R. Shi, F. Ouyang, Prof. J. Liu*
Institute of Functional Nano & Soft Materials (FUNSOM)
Jiangsu Key Laboratory for Carbon-based Functional Materials & Devices
Soochow University, Suzhou, Jiangsu Province, China
X. Chen, C. Chen, Dr. J. Yang, Prof. D. Sun*
Institute of Chemicobiology and Functional Materials,
School of Chemical Engineering,
Nanjing University of Science and Technology,
200 Xiao Ling Wei Street, Nanjing, Jiangsu Province, China
† These authors contribute equally to this manuscript.
Correspondence:
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2. 500 nm
200 nm
50 nm
20 nm a b c d
Fig. S1 TEM images of bare BC nanofibers under different magnification. (a) An overview of the BC nanofibers; (b-c) A zoomed-in view of BC nanofibers; (d) A single BC nanofibers.

3. Ti
Fig. S2 Energy-dispersive spectroscopy (EDX) spectra of the hybrid nanofibers.

4. Fig. S3 MALDI-TOF mass spectra of the tryptic digest mixture of β-casein and BSA (1:1, w/w) before enrichment.

5. (a)
(b)
(c)
Fig. S4 (a-c) MALDI-TOF mass spectra of the digest of -casein by the pre-treated tips. Dilution series: 1X, 0.1X, 0.01X respectively, and loading amount for (c): 17 pmol. The phosphorylated fragments and their de-phosphorylated counterparts indicated by * and #, respectively.

6. (a)
(b)
(c)
Fig. S5 (a-c) MALDI-TOF mass spectra of the enriched samples from a mixture of analytes in a series of mass ratios including1:1; 1:10; 1:100 of digested -casein and BSA, using the pre-treated tips. The phosphorylated fragments and their de-phosphorylated counterparts indicated by * and #, respectively.

7. (a)
(b)
Fig. S6 (a) The standard calibration curve using the BCA protein colorimetric detection kit. (b) The measurements of the enrichment capacity of three different materials, including post-treated nanofibers, pre-treated nanofibers, and the commercial TiO2 tip. Error bar: standard deviation (n=3).