title: Quantifying the effect of experimental design choices for in vitro scratch assays.
abstract: Scratch assays are often used to investigate potential drug treatments for chronic wounds and cancer. Interpreting these experiments with a mathematical model allows us to estimate the cell diffusivity, D, and the cell proliferation rate, λ. However, the influence of the experimental design on the estimates of D and λ is unclear. Here we apply an approximate Bayesian computation (ABC) parameter inference method, which produces a posterior distribution of D and λ, to new sets of synthetic data, generated from an idealised mathematical model, and experimental data for a non-adhesive mesenchymal population of fibroblast cells. The posterior distribution allows us to quantify the amount of information obtained about D and λ. We investigate two types of scratch assay, as well as varying the number and timing of the experimental observations captured. Our results show that a scrape assay, involving one cell front, provides more precise estimates of D and λ, and is more computationally efficient to interpret than a wound assay, with two opposingly directed cell fronts. We find that recording two observations, after making the initial observation, is sufficient to estimate D and λ, and that the final observation time should correspond to the time taken for the cell front to move across the field of view. These results provide guidance for estimating D and λ, while simultaneously minimising the time and cost associated with performing and interpreting the experiment.
authors.affiliation: School of Mathematical Sciences, Queensland University of Technology (QUT), Brisbane, Australia; Institute of Health and Biomedical Innovation, QUT, Brisbane, Australia.
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Johnston
authors.affiliation: School of Mathematical Sciences, University of Adelaide, Adelaide, Australia.
authors.forename: Joshua V
authors.initials: JV
authors.lastname: Ross
authors.affiliation: School of Mathematical Sciences, University of Adelaide, Adelaide, Australia.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Binder
authors.affiliation: School of Mathematical Sciences, Queensland University of Technology (QUT), Brisbane, Australia; Institute of Health and Biomedical Innovation, QUT, Brisbane, Australia.
authors.forename: D L
authors.initials: DL
authors.lastname: Sean McElwain
authors.affiliation: Institute of Health and Biomedical Innovation, QUT, Brisbane, Australia.
authors.forename: Parvathi
authors.initials: P
authors.lastname: Haridas
authors.affiliation: School of Mathematical Sciences, Queensland University of Technology (QUT), Brisbane, Australia; Institute of Health and Biomedical Innovation, QUT, Brisbane, Australia. Electronic address: matthew.simpson@qut.edu.au.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Simpson
mesh_terms: D016475:3T3 Cells; D000465:Algorithms; D000818:Animals; D001499:Bayes Theorem; D002465:Cell Movement; D049109:Cell Proliferation; D019295:Computational Biology / Q000379:methods; D005347:Fibroblasts / Q000166:cytology*; D051379:Mice; D008954:Models, Biological; D015203:Reproducibility of Results; D012107:Research Design
keywords: Approximate Bayesian computation; Cell motility; Cell proliferation; Experimental design; Scratch assay