Characterization and quantification of biological micropatterns using cluster SIMS

• Published in: Surface and interface analysis 2011-01, Vol.43 (1-2), p.555-558
• Main Authors: Chen, Li-Jung, Shah, Sunny S., Verkhoturov, Stanislav V., Revzin, Alexander, Schweikert, Emile A.
• Format: Article
• Language: English
• Subjects: Atomic, molecular, and ion beam impact and interactions with surfaces; Biological; biological micropatterns; Biosensors; Bombardment; C60 SIMS; cluster SIMS; collagen micropatterns; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; event-by-event bombardment/detection; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Indium tin oxide; micropatterns; Patterning; Physics; Secondary ion mass spectrometry; Self assembly; single-impact SIMS; Surface chemistry
• ISSN: 0142-2421; 1096-9918; 1096-9918
• DOI: 10.1002/sia.3399

Micropatterning is used widely in biosensor development, tissue engineering and basic biology. Creation of biological micropatterns typically involves multiple sequential steps which may lead to cross‐contamination and contribute to suboptimal performance of the surface. Therefore, there is a need to develop novel strategies for characterizing location‐specific chemical composition of biological micropatterns. In this paper, C60+ time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) operating in the event‐by‐event bombardment/detection mode was used for spatially resolved chemical analysis of micropatterned indium tin oxide (ITO) surfaces. Fabrication of the micropatterns involved multiple steps including self‐assembly of poly(ethylene glycol)‐silane (PEG‐silane), patterning of photoresist, treatment with oxygen plasma and adsorption of collagen (I). The ITO surfaces were analyzed with 26‐keV C60+ SIMS run in the event‐by‐event bombardment/detection mode at different steps of the modification process. We were able to evaluate the extent of cross‐contamination between different steps and quantify coverage of the immobilized species. The methodology described here provides a novel means for characterizing the composition of biological micropatterns in a quantitative and spatially resolved manner. Copyright © 2010 John Wiley & Sons, Ltd.