FULL PAPER Cellular architecture and migration behavior of fibroblast cells on polyhydroxyoctanoate (PHO): A natural polymer of bacterial origin Tomasz Witko 1 | Daria Solarz 1 | Karolina Feliksiak 1 | Zenon Rajfur 1 | Maciej Guzik 2 1 Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Krakow, Poland 2 Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Krakow, Poland Correspondence Maciej Guzik, Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Niezapominajek 8, Krakow 30-239, Poland. Email: ncguzik@cyfronet.pl Abstract Biodegradable and biocompatible novel materials of natural origin are gaining more and more attention in recent years. These so called biopolymers, characterized by their biointegrity and biocompatibility, find completely new and promising applica- tions in biomedical sciences. The presented work focuses on the medium chain length elastomeric polyhydroxyalkanoate biopolymer—polyhydroxyoctanoate (PHO). This biopolymer is fully biodegradable without formation of harmful byproducts.We investigated PHO's physical properties with nanoindentation technique and scratch testing to determine Young's modulus and friction coefficient. Further, the work focused on the impact of PHO, used as growth substrate, on the physiology and mor- phology of mouse embryonic fibroblast cells (MEF 3T3). Application of fluorescent staining protocols and advanced microscopic techniques allowed to study the mor- phological changes in the cytoskeletons of cells grown on PHO and also gave an insight into their migration strategies on the polymer surface. We found that PHO exhibits no cellular cytotoxicity, similarly to a glass substrate. MEF cells spread better on glass surface than on each tested PHO substrate though there was almost no dif- ference between PHO substrates cast from different solvents. However, a detailed analysis of actin and microtubule cytoskeletal architecture reveals changes in the density of actin and microtubular networks. Migration of MEF cells on PHO sub- strates was slower than on the glass substrate. To elucidate the molecular mecha- nisms of observed changes in cytoskeletal architecture and migration parameters can be of special interest for future medical application of PHO polymer. KEYWORDS biopolymers, confocal microscopy, cytoskeleton, migration, polyhydroxyalkanoates 1 | INTRODUCTION Mechanical and chemical properties of the environment influence the structure and morphology of living cells. The ability of an eukaryotic cell to resist deformation during motility, to change shape and to maintain intracellular transport comes from the presence of the cytoskeleton of an interconnected network of filamentous polymers and regulatory proteins located in the cell body. [1–3] Cells, cultured on substrates with different elasticity, undergo a number of intricate mechanical interactions mediated by focal adhesions and other adhesive structures. [1,2] It is known that certain migrating cells (i.e., fibroblasts) respond to substrate rigidity by orienting movement Received: 28 February 2019 Revised: 31 May 2019 Accepted: 24 June 2019 DOI: 10.1002/bip.23324 Biopolymers. 2019;e23324. wileyonlinelibrary.com/journal/bip © 2019 Wiley Periodicals, Inc. 1 of 12 https://doi.org/10.1002/bip.23324