Mussel Adhesive Protein Provides Cohesive Matrix for Collagen Type-1Α

Supporting Information Mussel adhesive protein provides cohesive matrix for collagen type-1α ______

Nadine R. Martinez Rodrigueza, Saurabh Dasb, Yair Kaufmanb, Wei Weic, Jacob N.

Israelachvilib,c,1 and J. Herbert Waiteb,c,1

aDepartment of Molecular, Cell & Developmental Biology, University of California, Santa

b Barbara, California 93106, USA; Department of Chemical Engineering, University of California,

Santa Barbara, California 93106, USA; cMaterials Research Laboratory, University of California,

Santa Barbara, California 93106, USA; dDepartment of Chemistry and Biochemistry, University

of California, Santa Barbara, California 93106, USA.

1Corresponding authors:

Email: [email protected], Phone: (805) 893-8407, Fax: (805) 893-7870.

Email: [email protected], Phone: (805) 893-2817

Keywords: mussel foot proteins, collagen type-1, mfp-3 (a)

(b) (c)

Figure S1. QCM frequency and dissipation changes upon adsorption of (a) mfp-3f, (b) mfp-3s and collagen type-1 to TiO2. In this multi-step adsorption, mfp-3f, mfp-3s or collagen type-1 was adsorbed to a TiO2 surface. Buffer addition of 0.1 M sodium acetate buffer, pH 3.0 and 0.25 M

KNO3 or 0.1 M phosphate buffer, pH 7.5 and 0.25 M KNO3 was added as indicated in the figures.

(a) (b) (c)

Figure S2. (a) AFM image of collagen type-1 deposited onto mica and scanned in the presence of 0.1 M sodium acetate buffer, pH 3.0 and 0.25 M KNO3. (b) Enlarged 1.5 µm x 1.5 µm image of (a). (c) Mica surface was rinsed and imaged with 0.1 M phosphate buffer, pH 7.5 and 0.25 M

KNO3 buffer. (a) (b)

Figure S3. (a) AFM image of collagen type-1 deposited onto mica and scanned in the presence of 0.1 M phosphate buffer, pH 7.5 and 0.25 M KNO3. (b) Enlarged 1.5 µm x 1.5 µm image of

Figure S4. Representative force vs. distance plots for mcfp-3 slow deposited at Cmfp3s = 20

µg/mL in 0.1 M sodium acetate buffer, pH 3.0 and 0.25 M KNO3 and with collagen (CCOL1A1 = 25 µg/mL) injected between the two films in 0.1 M sodium acetate buffer, pH 3.0 and 0.25 M

Figure S5. Representative force vs. distance plot showing the interaction between two symmetric collagen type-1 films deposited at 25 µg/mL in 0.1 M sodium acetate buffer, pH 3.0 and 0.25 M KNO3. (a)

Figure S6. Effect of collagen on symmetric mfp3F with and without periodate treatment.

Symmetric configuration of mfp-3f at acidic conditions (pH 3.0) showed strong cohesion for

2 2 short (tc ~ 2 min, Wad = -3.4 0.6 mJ/m ) and long (tc = ~ 60 min, Wad = -4.8 mJ/m ) contact times

(Fig a). Mfp-3f protein films were subjected to oxidation with periodate (Cperiodate = 500 pm) at -2 pH 3.0. There was a loss in cohesion after short contact, Wad = -0.9 1.1 mJ m and Wad = -3.7

-2 0.9 mJ m after 1h contact after periodate treatment. Collagen type-1 (Ccollagen= 25 µg/ mL) was then added to the bulk solution of the periodate-treated symmetric mfp-3f films at pH 3.0 (Fig.

2 2 11b). Cohesion was recovered at short contact, Wad = -3.3 0.9 mJ/m and Wad = -4.9 mJ/m for long time, where collagen bridged to two oxidized mfp-3f films. Long range repulsion was apparent during approach in all runs due to steric and coulombic interactions as both collagen and mfp-3f have high (basic) pIs.