Title:	Biaxial stretcher with vision-based force sensing for estimating anisotropy of single cells
Authors:	Marwah, Himanshu Bhatt, Hetarth Fartyal, Neeraj Nautiyal, Rohit Veer, Sukh Pullarkat, Pramod A Balakrishnan, Sreenath
Keywords:	Biaxial stretcher Vision-based force sensing Cellular anisotropy SU-8 micromechanism Glioblastoma cells
Issue Date:	6-Apr-2026
Publisher:	Journal of Micro and Bio Robotics
Citation:	Journal of Micro and Bio Robotics, 2026, Vol. 22, AR No. 9
Abstract:	Mechanical properties of single cells offer insight into organismal development, disease progression, and mechanotransduction. Yet, estimating the complete mechanical state of single cells, involving multiple parameters, remains challenging due to limited deformation modes available in existing techniques and complex instrumentation. To address this gap, we are developing several compliant micromechanisms that together enable multiple modes of cell manipulation on a single chip. Building on an earlier uniaxial stretcher, here we demonstrate a biaxial stretching mechanism with vision-based force sensing. Because the mechanism uses elastic beams for actuation, stretching forces can be computed from optical displacement measurements using a closed-form analytical model derived from beam theory. This obviates the need for dedicated force sensors thereby simplifying device fabrication and operation. The force displacement relations were validated on macro- and microscale prototypes. The device is microfabricated out of SU-8 using a two-layer photolithography process, yielding an array of miniature stretchers that can be mounted on a coverslip for high-resolution imaging during manipulation. We stretch U87-MG human glioblastoma cells biaxially, compute bulk stiffness, stress and strain in orthogonal directions using microscopy and further fit 2D Fung’s model to investigate anisotropy. This biaxial stretcher can be combined with additional modules (e.g., for shear or twist) to realize a multimodal single-cell mechanophenotyping platform for comprehensive analysis of cellular mechanics. Such a versatile platform represents a new approach to single-cell mechanical characterization.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/8702
ISSN:	2194-6426
Alternative Location:	https://doi.org/10.1007/s12213-026-00206-w
Copyright:	© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2026
Appears in Collections:	Research Papers (SCM)

Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.