| AVS 54th International Symposium | |
| Biomaterial Interfaces | Thursday Sessions |
| Session BI+AS+NS-ThA |
| Session: | Surface Analysis and Related Methods for Biological Materials |
| Presenter: | P. Kingshott, The University of Aarhus, Denmark |
| Authors: | S. Pillai, The University of Aarhus, Denmark G. Singh, The University of Aarhus, Denmark C. Blomfield, Kratos Analytical Ltd, UK A. Roberts, Kratos Analytical Ltd, UK R.L. Meyer, The University of Aarhus, Denmark P. Kingshott, The University of Aarhus, Denmark |
| Correspondent: | Click to Email |
Controlled patterning of surfaces with different chemistries and structures at nanoscale length scales is highly desirable for understanding the fundamental mechanisms of protein and cell interactions with biomaterials. The use of nanoparticles (NPs) to pattern surfaces by colloidal lithography or templating using one type of NP is well known for applications such as biosensors,1 biomaterials2 and tissue engineering.3 We demonstrate that by using mixed nanoparticles unique highly-ordered patterns can be obtained by simple self-assembly from buffer onto hydrophobic surfaces from both concentrated and dilute two-component NP suspensions.4 The new method uses suspensions of poly(styrene) (PS) NPs of different size (d = 500 to 60nm) with different NP ratios and volume fractions. The ordering is independent of the NP surface chemistry (sulfated, carboxylated, or aminated PS) or zeta potential and occurs over a broad pH range (4-10). The method is demonstrated for two types of hydrophobic surfaces, a commercial adhesive carbon tape and octadecyltrichlorosilane (OTS)-modified glass where patterns of hexagonally packed large particles are inter-dispersed with smaller particles. However, very poor ordering is achieved using gold, mica and HOPG (highly oriented pyrolytic graphite) as substrates. The morphologies of the nanoparticle assemblies are characterised extensively by SEM and AFM. In addition, XPS and ToF-SIMS are used to characterise the surface chemistry of the NP surfaces, which also provides knowledge of the mechanisms of NP assembly by showing that the ordering is most likely associated with charge screening by buffer salts resulting in an entropically driven assembly process. These preliminary results indicate that use of two component NP assemblies opens up the possibilities of decorating surfaces with well-defined chemical nanopatterns capable of selective attachment of different proteins and/or protein resistant molecules.
1I. Willner, and E. Katz, Angew. Chem., Int. Ed. 2000, 39, 1180.
2H. Agheli , J. Malmstrom, E.M. Larsson, M. Textor, D.S. Sutherland, Nano Lett. 2006, 6, 1165.
3S.N. Bhatia , U.J. Balis, M.L. Yarmush, M. Toner, FASEB J. 1999, 14, 1883.
4R. Mukhopadhyay, O. Al-Hanbali, S. Pillai, A. Gry Hemmersam, R.L. Meyer, C.A. Hunter, K.J. Rutt, F. Besenbacher, S.M. Moghimi, P. Kingshott, submitted.