Adsorption of human plasma albumin and fibronectin onto nanostructured black silicon surfaces (2)

SUPPORTING INFORMATION Adsorption of Human Plasma Albumin and Fibronectin onto Nanostructured Black Silicon Surfaces Duy H K Nguyen,† Vy T.H Pham,† Mohammad Al Kobaisi,† Chris Bhadra,† Anna Orlowska,‡ Shahram Ghanaati,‡ Berardo Mario Manzi, Vladimir A Baulin, Saulius Joudkazis,† Peter Kingshott,† Russell J Crawford,§ and Elena P Ivanova*,† † Department of Chemistry and Biotechnology, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn VIC 3122, Australia ‡ Frankfurt Orofacial Regenerative Medicine, University Hospital Frankfurt, Theodor-Stern- Kai 7, D-60590 Frankfurt am Main, Germany  Department d’Enginyeria Quimica, Universitat Rovira i Virgili, 26 Av dels Paisos Catalans, 43007 Tarragona, Spain § School of Science, College of Science, Engineering and Health, RMIT University, Melbourne VIC 3001, Australia S1 Quantification of adsorbed protein The thickness and surface coverage of human serum albumin and plasma fibronectin on the bSi surfaces were calculated from the XPS data The thickness of adsorbed proteins (z) was calculated using the overlayer equation shown below,1-8 where the bSi surface is assumed to have random roughness and variable emission angles: 𝑧 = −𝜆𝐼𝑀𝐹𝑃 × cos 𝜃 × ln (1 − 𝐼 ) 𝐼∞ where I and I∞ are the %N recorded on the protein coated bSi surfaces, and %N present in each protein, respectively λIMFP is the mean free path of N 1s photoelectrons generated from the protein overlayers (it is assumed to be 2.5 nm), and cos θ is the angle between the sample and analyser.8 In this case we use θ=57.3°: the average angle of emission for a randomly rough particle-like surface for bSi surfaces and θ=0° for control silicon wafers.8 The reference value for I∞ is determined by calculating % N from the atomic composition for each protein which is obtained by submitting the sequence or the SwissProt/TrEMBL accession number for the protein into the PortParam calculator (http://web.expasy.org/protparam/) For human fibronectin this is determined to be 17.7 %N and for human serum albumin this is 16.7 %N Once the thickness of each protein is determined; the surface coverage (Θ) is calculated in ng/cm2 assuming the density of dry protein to be 1.4 g/cm 3.6 The calculation assumes the surface is uniformly covered with protein and occupies a volume of cm × cm × z.8 𝛩 = 𝑧 × 1.4 × 102 Table S1 Protein Uptake on bSi and Si Wafer Surfaces Using the Overlayer Equation Obtained from XPS Elemental Analysis protein concentration adsorbed protein mass protein molecule uptake (àg/mL) (ng/cm2) (ì109) (molecule/cm2) albumin fibronectin bSi Si wafer bSi Si wafer 0.4 5.7 ± 0.2 17.2 ± 3.1 51.6 ± 1.8 155.8 ± 28.1 4.0 20.3 ± 2.3 38.8 ± 8.3 183.8 ± 20.8 351.4 ± 75.2 40.0 60.8 ± 0.6 52.0 ± 13.8 550.6 ± 5.4 470.9 ± 125.0 0.3 4.5 ± 0.3 * 6.2 ±0.4 * 3.0 8.4 ± 1.9 27.8 ± 4.5 11.5 ± 2.6 38.0 ± 6.2 30.0 100.0 ± 6.5 126.3 ± 22.1 136.9 ± 8.9 172.9 ± 30.2 * Below detection limit Table S2 Topographical Analysis of the bSi Surface with Protein Adsorption Taking Place at Different Bulk Protein Concentrations over a Scanning Area of 10 àm ì 10 àm 0.4 albumin (µg/mL) 4.0 40.0 82.3 ± 16.9 96.3 ± 21.4 141.3 ± 18.7 803.4 ± 96.8 Sskw 804.6 ± 67.9 1097.3 ± 249.0 1103.4 ± 46.4 -0.4 ± 0.1 Skur -0.5 ± 0.1 0.2 ± 0.5 -0.5 ± 0.1 1.4 ± 0.2 1.0 ± 0.5 2.4 ± 0.4 fibronectin (µg/mL) -0.1 ± 0.3 PBS Sq (nm) 0.3 3.0 30.0 76.5 ± 9.4 Smax (nm) 104.1 ± 7.5 144.0 ± 6.3 135.4 ± 4.6 803.4 ± 96.8 Sskw 1010.4 ± 126.3 1033.9 ± 60.1 1019.7 ± 142.1 -0.4 ± 0.1 Skur -0.7 ± 0.1 -0.6 ± 0.2 -0.4 ± 0.1 1.4 ± 0.2 0.3 ± 0.2 -0.3 ± 0.2 -0.5 ± 0.1 roughness parameter Sq (nm) PBS 76.5 ± 9.4 Smax (nm) (a) (b) 2720 CCD cts 2937 CCD cts 1292 CCD cts 2087 CCD cts 900 CCD count CCD count 900 850 800 750 2000 Raman shift (cm-1) 4000 850 800 750 2000 4000 Raman shift (cm-1) Figure S1 Raman activity of the water distribution on bSi surfaces (a) Depth profile of 10 àm (height) ì àm (width) areas showing the penetrating depth of water from the tip to the foot of the pillars, demonstrating the absence of air retained between the nanopillars (b) The space between the pillar tips and water layer, showing a homogenous spreading of water on the surface of bSi Scale bar is 0.3 µm Reference (1) Bramblett, A L.; 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Quantification of adsorbed protein The thickness and surface coverage of human serum albumin and plasma fibronectin on the bSi surfaces were calculated from the XPS data The thickness of adsorbed... (http://web.expasy.org/protparam/) For human fibronectin this is determined to be 17.7 %N and for human serum albumin this is 16.7 %N Once the thickness of each protein is determined; the surface... Raman activity of the water distribution on bSi surfaces (a) Depth profile of 10 µm (height) ì àm (width) areas showing the penetrating depth of water from the tip to the foot of the pillars,