title: Characterization of biomechanical properties of cells through dielectrophoresis-based cell stretching and actin cytoskeleton modeling.
abstract: BACKGROUND
  Cytoskeleton is a highly dynamic network that helps to maintain the rigidity of a cell, and the mechanical properties of a cell are closely related to many cellular functions. This paper presents a new method to probe and characterize cell mechanical properties through dielectrophoresis (DEP)-based cell stretching manipulation and actin cytoskeleton modeling.
  
  
  METHODS
  Leukemia NB4 cells were used as cell line, and changes in their biological properties were examined after chemotherapy treatment with doxorubicin (DOX). DEP-integrated microfluidic chip was utilized as a low-cost and efficient tool to study the deformability of cells. DEP forces used in cell stretching were first evaluated through computer simulation, and the results were compared with modeling equations and with the results of optical stretching (OT) experiments. Structural parameters were then extracted by fitting the experimental data into the actin cytoskeleton model, and the underlying mechanical properties of the cells were subsequently characterized.
  
  
  RESULTS
  The DEP forces generated under different voltage inputs were calculated and the results from different approaches demonstrate good approximations to the force estimation. Both DEP and OT stretching experiments confirmed that DOX-treated NB4 cells were stiffer than the untreated cells. The structural parameters extracted from the model and the confocal images indicated significant change in actin network after DOX treatment.
  
  
  CONCLUSIONS
  The proposed DEP method combined with actin cytoskeleton modeling is a simple engineering tool to characterize the mechanical properties of cells.
authors.affiliation: Key Laboratory of Instrumentation Science and Dynamic Measurement, Ministry of Education, North University of China, Room 418, Building No. 14, No. 3 Xueyuan Road, Taiyuan, 030051, Shanxi, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Bai
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, SAR of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, SAR of China.
authors.forename: Henry K
authors.initials: HK
authors.lastname: Chu
authors.affiliation: Department of Biomedical Engineering, College of Mechanics, Taiyuan University of Technology, No. 79, West Yingze Street, Taiyuan, 030024, Shanxi, China.
authors.forename: Kaiqun
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory of Instrumentation Science and Dynamic Measurement, Ministry of Education, North University of China, Room 418, Building No. 14, No. 3 Xueyuan Road, Taiyuan, 030051, Shanxi, China.
authors.forename: Qiulin
authors.initials: Q
authors.lastname: Tan
authors.affiliation: Key Laboratory of Instrumentation Science and Dynamic Measurement, Ministry of Education, North University of China, Room 418, Building No. 14, No. 3 Xueyuan Road, Taiyuan, 030051, Shanxi, China.
authors.forename: Jijun
authors.initials: J
authors.lastname: Xiong
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, SAR of China. medsun@cityu.edu.hk.
authors.forename: Dong
authors.identifier: http://orcid.org/0000-0003-3945-4037
authors.initials: D
authors.lastname: Sun
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D001696:Biomechanical Phenomena; D045744:Cell Line, Tumor; D003362:Cost-Benefit Analysis; D004586:Electrophoresis / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D055595:Mechanical Phenomena; D040542:Mechanotransduction, Cellular; D008954:Models, Biological; D013314:Stress, Mechanical
keywords: Cell stretching; Cytoskeleton model; Dielectrophoresis; Mechanical property; Optical tweezers