Supporting Information Facile preparation of mussel inspired polyurethane hydrogel and its rapid curing behavior Peiyu Sun, Jing Wang, Xiong Yao, Ying Peng, Xiaoxiong Tu, Pengfei Du, Zhen Zheng * and Xinling Wang * School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites (Shanghai Jiao Tong University), Shanghai Jiao Tong University, Shanghai 200240, China * Corresponding author. E-mail: xlwang@sjtu.edu.cn, zzheng@sjtu.edu.cn. 1
MR spectroscopy of PU-LDA and LDA PU-LDA LDA DMS a 1 150 140 130 120 110 ee 2 1 b k i 6 k k 4 5 k k 3 k 2 1 a 2 a 3 c 1 +c 2 g 3 g 1 j d 1 fj 1 d h 2 2 g 2 e 2 i c 2 c 1 b a 3 a 1 a 2 a a 2 1 m a 3 b c 1 k 6 k k 4 5 k k k 2 3 1 c 2 e 1 g 1 g 3 h g f 2 i n k 1 k j k 1 6 2 j 2 k k 3 5 k 4 h j 2 g 3 j 1 f g 1 g 2 180 160 140 120 100 80 60 40 20 Figure S1 13 C-MR of PU-LDA and LDA In 13 C-MR for PU-LDA, chemical shifts at 158.6 ppm an58.1ppm are corresponding to carbons in two urea groups ( -C--). Also, chemical shifts at 145.6ppm, 144.1ppm, 130.3ppm, 119.7ppm, 116.5ppm an16.0ppm are corresponding to carbons of the benzyl ring in PU-LDA, which reveal that LDA was successfully introduced into the polyurethane backbone. Wherein, chemical shifts at 145.6ppm an44.1ppm are attributed to carbons of C- in the catecholic group. There are no new chemical shifts for benzyl ring for PU-LDA compared with LDA, which indicated no reaction between C and catecholic hydroxyls during the synthesis of PU-LDA. 2
Synthesis of Lysine-Dopamine (LDA) A dopamine containing chain extender lysine-dopamine (LDA) was synthesized from lysine and dopamine. The detailed process and conditions are illustrated in Scheme S1. 2 L-Lysine 2 C (Boc) 2 TF/ 2 ac 3, 30 o C, 24h C (Boc) 2 -Lysine- S DCM, EDC-Cl RT, 5.5h C (Boc) 2 -Lysine-S 2 Cl Dopamine-Cl Me, RT, 12h C (Boc) 2 -Lysine-dopamine RT, 3h Cl/ethyl acetate C Lysine-dopamine 2 2 Scheme S1. The reaction conditions for the synthesis of LDA. (1) Synthesis of (Boc) 2 -Lysine- (BL) L-lysine (10mmol) was dissolved in the mixed solvent (150mL deionized water and 50mL tetrahydrofuran) in a flask an2.6g ac 3 were added. Then Di-t-butyl dicarbonate (Boc anhydride) (150mmol) was added drop-wise into the flask. The reaction was carried out at 30 o C for 24h under a nitrogen atmosphere. A rotary evaporator was used to remove the solvent and by-product. 1 mol/l Cl aqueous solution was added drop-wise into the flask until the p was approximately 3. Ethyl acetate was applied to extract the product, and then evaporated to isolate the product. Finally, the product was dried in an oven (60 o C) for 24h. The yield of BL was 92%. 1 -MR (DMS-d6, 300 Mz, δ in ppm): 12.42 (br.s, 1, C), 6.98 (d, 1, -C-C<), 6.78 (t, 1, -C-C 2 -), 3.78 (m, 1, - 3
C-C<), 2.85 (m, 2, -C-C 2 -), 1.85-1.05 (m, 24, -C 2 - and C 3 ). (2) Synthesis of (Boc) 2 -Lysine-S (BL) The BL synthesized in the first step was dissolved in 125mL dichloromethane, then - hydroxysuccinimide (S) was added into the flask (S in excess). 1-ethyl-3-(3- dimethyllaminopropyl)carbodiimide hydrochloride(edc-cl) was dissolved in the dichloromethane at 0 o C (2 mol equivalents relative to S). After 30min, the reaction was warmed to room temperature and allowed to proceed for another 5.5h under a nitrogen atmosphere. Pure water was used to wash the solution 3 times; the solvent was removed, and the product dried in an oven (60 o C). The yield of BL was about 88%. 1 -MR (DMS-d6, 300 Mz, δ in ppm): 7.55(d, 1, -C-C<), 6.78 (t, 1, - C-C 2 -), 4.27(m, 1, -C-C<), 2.96-2.65 (m, 6, -(C-C 2 ) 2 and -C-C 2 -), 1.85-1.05 (m, 24, -C 2 - and C 3 ). (3) Synthesis of (Boc) 2 -Lysine-dopamine (BLDA) The BL synthesized in the second step was dissolved in 125mL methanol. Dopamine hydrochloride (Dopamine-Cl) was added into the flask (Dopamine-Cl in excess). After the Dopamine-Cl dissolved, triethylamine (TEA) was added into the solution (the mole ratio of Dopamine-Cl: TEA was 1.5:1.3). The reaction proceeded for 12h at room temperature under a nitrogen atmosphere. The solvent and TEA were removed. Ethyl acetate was applied to dissolve the product, followed by washing with deionized water 3 times. The ethyl acetate was evaporated and the product was dried in an oven (45 o C) for 24h. The yield of BLDA was about 71%. 1 -MR (DMS-d6, 300 Mz, δ in ppm): 8.60-8.90 (d, 2, -Ar() 2 ), 7.76(t, 1, -C-C 2 -), 6.85-6.65(m, 3, - C-C< and -C-C 2 -), 6.64-6.30(m, 3, -Ar), 3.78 (m, 1, -C-C<), 3.28-2.98 (m, 2, -C-C 2 -), 2.85 (m, 2, -C-C 2 -), 2.45 (m, 2,-C-C 2 -C 2 -), 1.85-1.05 (m, 24, -C 2 - and C 3 ). 4
(4) Synthesis of lysine-dopamine (LDA) The BLDA synthesized above was dissolved in 100mL ethyl acetate. 50mL Cl/ethyl acetate solution was then added, and the reaction was carried out for 3h at room temperature under a nitrogen atmosphere. After reaction, the solvent was removed and the product was oven-dried (45 o C) for 24h. The final product is a bis-hydrochloride of LDA. The yield of LDA was about 99%. 1 -MR (DMSd6, 300 Mz, δ in ppm): 8.60-8.90 (d, 2, -Ar() 2 ), 8.46 (t, 1, -C-C 2 ), 8.13 (s, 2, >C- 2 ), 7.79 (s, 2, -C 2-2 ), 6.64-6.30(m, 3, -Ar), 3.64(m, 1, >C- 2 ), 3.42-3.10 (m, 2, - C-C 2 -), 2.73 (m, 2, -C 2-2 ), 2.53 (m, 2,-C-C 2 -C 2 -),1.85-1.05 (m, 6, -C 2 -). BL BL BLDA LDA 13 12 11 BL BL BLDA LDA 14 12 10 8 6 4 2 ppm Figure S2 1 -MR spectra of BL, BL, BLDA and LDA. Q-Tof Premier TM (Waters, USA) was used to identify the molecular structure of the synthesized LDA. The signals appearing at 282.18 (PPM = -6.4) and 563.35 (PPM = 1.1) were assigned to the value of (m+1, C 14 24 3 3 ) and (2m+1, C 28 47 6 6 ) in cation mode, respectively. 5
Movies for the curing of mussel adhesive protein and mussel mimetic polyurethane (PU-LDA) Movie S1. Mussel adhesive protein: secreting, attaching, and curing underwater. Movie S2. Mussel mimetic polyurethane PU-LDA: injecting, attaching, and curing underwater. (1) A mussel secretes the adhesive liquid to the surface of tank A marine mussel was left in a glass tank under seawater. The adhesive liquid with mussel adhesive proteins (MAPs) stockpiled in the foot (acidic environment) was secreted and injected on the surface of the tank under seawater environment (p=8). Instantaneously, a small byssus including byssal thread and byssal plaque formed, which fasten mussel itself to the tank. (2) An injector injects liquid PU-LDA/FeCl 3 solution to the surface of glass slide A glass slide was left under alkali water. The PU-LDA/FeCl 3 solution (acidic environment) stored in the injector was injected onto glass slide under alkali water. Instantaneously, a mussel mimetic polyurethane adhesive gel formed for the spontaneous cross-linking, and the hydrogel was fasten to the glass slide. 6