8th Workshop Ellipsometry, Dresden, March, 11 2014 Interaction of proteins with nanoporous titania substrates Maurizio Canepa Dipartimento di Fisica (DIFI) Università di Genova (UNIGE) canepa@fisica.unige.it www.fisica.unige.it/surfmag 1
People Chiara Chiara Toccafondi Toccafondi DIFI-UNIGE DIFI-UNIGE((present presentaddress addressitalian ItalianInstitute Instituteof oftechnology, Technology,Genova) Genova) Film& Film&SAMs SAMspreparation, preparation, SE SE(+ (+modeling), modeling), AFM, AFM,XPS... XPS... (PhD (PhDthesis thesisavailable, available, in inenglish) english) Francesco Francesco Bisio Bisio CNR-SPIN CNR-SPINGenova Genova modelling modelling Ornella Ornella Cavalleri Cavalleri DIFI-UNIGE DIFI-UNIGE AFM, AFM,bio-competences bio-competences Emanuele Emanuele Barborini Barborini TETHIS, TETHIS,Milan Milan Samples Samples Italian ItalianMIUR MIURFIRB FIRB2012-2015 2012-2015 grant grantrbap11etka_05 RBAP11ETKA_05 University Universityof ofgenova GenovaPRA PRA2011-12 2011-12 2
Complex organic-inorganic systems: route Model systems thiols/flat gold Aromatic Dithiols selenides Nanoporous Nanoporous Polymers (Au, (Au,TiO2) TiO2) Proteins 2D 2DN-Particle N-Particlearrays arrays Graphene (Au,Al,Au/Ag) (Au,Al,Au/Ag) Complex systems (sensors, bio-sensors) 3
Cluster Assembled films Sputtering of metal rod by He plasma seeded - cluster supersonic beam Deposition (Random stacking of Nps) Spheroids, size 10 nm Nano-porosity (density grading) High specific area Thickness (QM) (large uncertainty) Ex-situ oxidation (plasma) Previous works on cluster assembled Au films Bisio et al. Optical properties of cluster assembled nanoporous gold films PRB 2009 Bisio et al. Interaction of liquids with nanoporous cluster assembled Au films JPC 2010 4 Bisio et al. Interaction of alkanethiols with nanoporous cluster assembled Au films Langmuir 2011 Toccafondi et al. Yeast Cytochrome c Monolayer on Flat and Nanostructured Gold Films Studied by UV Vis Spectroscopic Ellipsometry Bionanoscience 2011
~15 kda Hard ~60 kda Soft Colour sensitive to deformation/ unfolding 5
Aims (in collaboration with TETHIS, Milan) Liquid + molecule penetration into a cluster-assembled intrinsically nanoporous structure Applications Nano-Filters, bioassays, photocatalysis Spectroscopic Ellipsometry M-2000 245-1700 nm +XPS, AFM In-depth info ( stratigraphy ) In-liquid measurements Info on nanoporosity ( B-EMA porosimetry ) 6
TiO2 films SiO2 substrates ( Wafer + native oxide, Suprasil) 20-150 nm nominal thickness XRD+Raman (TETHIS) structure: complex XPS oxidation uniformity roughness NP size ageing AFM Nominal thickness (nm) C. Toccafondi, PhD thesis 2013 7
SE Focus on 50 nm thickness ( nom. 40-60 ) AFM: uniform coverage (substrate fully covered), moderate roughness, stable XPS: high degree of oxidation down to the substrate B EM A MSE = 12 C. Toccafondi, PhD thesis 2013 8
In liquid 9 C. Toccafondi, PhD thesis 2013
lysozime Cfr. Arwin et al. PSS(a) 2000 (SiO2) C. Toccafondi, PhD thesis 2013 10
Albumin Cfr. Karlsson et al. JCIS 2003, TSF 2004 (SiO2) C. Toccafondi, PhD thesis 2013 11
YCC pole@190nm pole@190nm 12 12oscillators oscillators From FromTransmission Transmissionmeasurements measurements One only fit parameter: One only fit parameter: collective collective amplitude amplitude 12
YCC SAM @ (flat) Au 13
YCC SAM @ (flat) SiO2 abs in sol abs in sol Possible molecular change (oxidation state) upon interaction with substrate 14
YCC C. Toccafondi, PhD thesis 2013 15
YCC Filling values similar to Lysozime C. Toccafondi, PhD thesis 2013 16
Summary Educated use of B-EMA enough flexibility to deal with in-depth complexity ( morphologic, electronic) of cluster-assembled nanoporous TiO2 Reasonable reproduction of SE data in different ambient - in air: estimate of porosity - in liquid: pores ( outer and inner) filling - interaction with proteins of different size and structure - estimate of penetration - limited output on unfolding (especially for transparent molecules) 17