122 Int. J. Abrasive Technology, Vol. 3, No. 2, 2010 Copyright © 2010 Inderscience Enterprises Ltd. Bioaffinity limitations for anisotropically etched silicon microfluidics Anas Alazzam, Arvind Chandrasekaran*, Muthukumaran Packirisamy, Ion Stiharu and Rama Bhat Department of Mechanical Engineering, Concordia University, 1515 St. Catherine (o), Montreal QC, H3G2W1, Canada E-mail: azazzam@yahoo.com E-mail: achandra@alcor.concordia.ca E-mail: pmuthu@alcor.concordia.ca E-mail: istih@alcor.concordia.ca E-mail: rbhat@alcor.concordia.ca *Corresponding author Abstract: Immobilisation of biological specimens is an essential process in biomicrofluidics for micro total analysis systems (μTASs) applications, to carry out high throughput bioassays. Closed microfluidic channels restrict immobilisation feasibilities to only direct conjugation of the biomolecules with the channel surface through appropriate flow control-based incubation techniques. In this work, the limitations of bioaffinity on anisotropically etched silicon microfluidic channels have been studied. The flow behaviour within the microchannels has been analysed by solving the Navier-Stokes equation using finite element method (FEM). The results have been used to predict the immobilisation and rinsing behaviour within anisotropically etched trapezoidal and triangular microfluidic channels. Keywords: micro total analysis systems; μTASs; lab-on-a-chip; biosensing; microfluidics; finite element analysis; FEA; immobilisation; anisotropic etching; silicon; bioaffinity; stagnant flow. Reference to this paper should be made as follows: Alazzam, A., Chandrasekaran, A., Packirisamy, M., Stiharu, I. and Bhat, R. (2010) ‘Bioaffinity limitations for anisotropically etched silicon microfluidics’, Int. J. Abrasive Technology, Vol. 3, No. 2, pp.122–132. Biographical notes: Anas Alazzam received his BSc and MSc from Jordan University of Science and Technology, Jordan, in 2002 and 2004, respectively. He is currently pursuing his PhD in the Department of Mechanical and Industrial Engineering, Concordia University, Montreal, Quebec, Canada. His research interests include dielectrophoretic separation of human cells and biological applications of microdevices. Arvind Chandrasekaran completed his MASc from Concordia University in 2006 and has finished his Bachelor of Engineering in the Faculty of Mechanical Engineering from the University of Madras, India in 2003. He is currently a PhD candidate in Mechanical Engineering at Concordia University, Montreal, Canada. His main area of research is integrated micro total analysis systems, biophotonics and microfluidics.