IOP PUBLISHING JOURNAL OF MICROMECHANICS AND MICROENGINEERING J. Micromech. Microeng. 22 (2012) 095009 (10pp) doi:10.1088/0960-1317/22/9/095009 A micropillar-based on-chip system for continuous force measurement of C. elegans Ali Ghanbari 1, 3 , Volker Nock 2, 3 , Shazlina Johari 1, 3 , Richard Blaikie 2 , XiaoQi Chen 1 and Wenhui Wang 1 1 Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand 2 Department of Electrical and Computer Engineering, MacDiarmid Institute for Advanced Materials and Nanotechnology and the University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand E-mail: wenhui.wang@canterbury.ac.nz Received 26 April 2012, in final form 20 June 2012 Published 26 July 2012 Online at stacks.iop.org/JMM/22/095009 Abstract Caenorhabditis elegans is a well-established model organism and has been gaining interest particularly related to worm locomotion and the investigation of the relationship between muscle arms and the motion pattern of the nematode. In this paper, we report on a micropillar-based on-chip system which is capable of quantifying multi-point locomotive forces of a moving C. elegans. A Polydimethylsiloxane (PDMS) device was microfabricated to allow C. elegans to move in a matrix of micropillars in a channel, and an image processing method was developed to resolve the worm force from the bending pillars. The current micropillar-based system is able to measure force with a resolution of 2.07 μN for body width of 80 μm. Initial experiments have been conducted to collect a maximum force level for thirteen wild type worm samples. A maximum force level of 61.94 μN was observed from 1571 data points, based on which an average maximum force level was 32.61 μN for multi-point measurements. The demonstrated capabilities of the system can be an enabling technology that allows biologist to gain a better understanding of subtle force patterns of C. elegans and worm muscle development. (Some figures may appear in colour only in the online journal) 1. Introduction Due to its relative simplicity in anatomy, Caenorhabditis elegans (C. elegans), a soil-dwelling multicellular nematode, is widely used as a model organism for studies in cellular differentiation, neural networking and molecular genetics. With a fully sequenced genome [1] and favorable gestation times, the semi-transparent C. elegans has been successfully established as an experimental genetic system regarding the relationship between genes and locomotive behavior [2, 3]. In a normal environment, nematodes like C. elegans, exhibit a sinusoidal movement pattern induced by waves of muscle contraction and local bending of the cuticle [4, 5]. 3 These authors contributed equally to this work. Changes in the locomotive behavior of the nematodes can be induced by natural aging [6], structured environment [7], external exposure to toxins and drugs [8–10], or through the manipulation of specific genes [11–14]. Genetic modification in particular can be used to yield C. elegans mutants with different numbers of muscle arms, which are physical connections established between C. elegans muscles and the motor neurons via membrane extensions [15]. As muscle arms function as paths for muscles to receive stimulation from the nerve, their number is most likely to affect the motion pattern of the nematode. Determining the correlation between muscle arms and motion patterns can therefore be of specific implications in identifying the role of individual genes in locomotion, through the phenotypic locomotive behavior study [16]. On the smooth surface of agar 0960-1317/12/095009+10$33.00 1 © 2012 IOP Publishing Ltd Printed in the UK & the USA