Yufei Liuyufei Liu*1, Liyun Gao2, Huijuan Yan1, Jingfang Shangguan1, Zhen Zhang3 and Xia

Electronic Supporting Material

A cationic conjugated polymer coupled with exonuclease I: Application to the fluorometric determination of protein and cell imaging

Yufei LiuYufei Liu*1, Liyun Gao2, Huijuan Yan1, Jingfang Shangguan1, Zhen Zhang3 and Xia Xiang*3

1.School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, P. R. China;

2. Department of toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, Henan 453003, P. R. China;

3. Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, Hubei 430000, P. R. China

*Corresponding author. Tel: +86 373-3831662,E-mail addresses:;

Synthesis of PFP

PFP was synthesized according to previously reported methods [1, 2]. 1,4-phenyldiboronic acid, 2,7-dibromo-9,9-bis(6’-bromo-hexyl)-fluorene, Pd(dppf)Cl2 and potassium carbonate were mixed and vigorously stirred at 85°C for 24 h. After that, the mixture was cooled to precipitate by using methanol. The resulting precipitate was filtered and washed with methanol and acetone, as well as dried under vacuum. Then, trimethylamine was added dropwise to the above product which was dissolved in THF at-78°C in advance, and allowed to warm room temperature. The result precipitate was redissolvedby water. Extra 30% trimethylamine wasadded after the mixture above was cooled down to -78°C, then stirring the mixture at room temperature for 24 h. Finally, the PFP as a yellowpowder was obtained by precipitating using acetone. 1H NMR (400 MHz, CD3OD, ppm): δ 8.15-7.38 (m, 10H), 3.20 (t, 4H),3.00 (s, 18H), 2.24 (br, 4H), 1.55 (br, 4H), 1.17 (br, 8H), 0.75 (br, 4H).

Fig. S1FTIR spectrum(A) and zeta potential (B) of the as-prepared PFP.

Fig. S2Absorbance and fluorescence spectra of PFP(abs, a; em, b) and P1(abs, c; em, d).

Fig. S3 (A) Effects of Exo I concentration on FRET-induced fluorescence spectraexcited at 370 nm (from top to bottom: 0, 5, 10, 15, 20, 25, 30U). Insert: linear curve of the FRET ratio with different concentrations of Exo I. (B) Effects of the PFP concentration on the FRET ratio without and with Exo I excited at 370 nm (n=6).

Fig. S4 (A) Normalized FRET-induced fluorescence spectra in the presence of different concentrations of SA: 0, 2, 6, 10, 20, 100, 200, 1000, 2000 ngmL-1 in 1% serum. (B) Linear relationship between the FRET ratio and SA concentrations in 1% serum (n=6).

Fig. S5 Theschematic illustration of PFP and Exo I-based fluorescent strategy for FR detection.

Fig. S6 Normalized fluorescence spectra of the fluorescence strategy in response to the increasing concentrations of FR(0, 10, 20, 100, 200, 600, 1000 ngmL-1), Inset: Calibration curve for FR detection (n=6).

Fig. S7 Cell viability values estimated by MTT proliferation tests (n=6).

References

1. Xing XJ, Liu XG., He Y, Lin Y, Zhang CL, Tang HW,Pang DW (2013)Amplified fluorescent sensing of DNA using graphene oxide and a conjugated cationic polymer. Biomacromolecules 14:117-123.

2. Stork M, GaylordBS, Heeger A J, Bazan GC (2002) Energy transfer in mixtures of water- soluble oligomers: effect of charge, aggregation, and surfactant complexation. Adv Mater 14:361-366.