Femtosecond laser micro‐machined polyimide films for cell scaffold applications

Abstract

Engineering of sophisticated synthetic 3D scaffolds that allow controlling behaviour and location of the cells requires advanced micro/nano-fabrication techniques. Ultrafast laser micro-machining employing a 1030-nm wavelength Yb:KGW femtosecond laser and a micro-fabrication workstation for micro-machining of commercially available 12.7 and 25.4 μm thickness polyimide (PI) film was applied. Mechanical properties of the fabricated scaffolds, i.e. arrays of differently spaced holes, were examined via custom-built uniaxial micro-tensile testing and finite element method simulations. We demonstrate that experimental micro-tensile testing results could be numerically simulated and explained by two-material model, assuming that 2-6 μm width rings around the holes possessed up to five times higher Young's modulus and yield stress compared with the rest of the laser intacted PI film areas of 'dog-bone'-shaped specimens. That was attributed to material modification around the micro-machined holes in the vicinity of the position of the focused laser beam track during trepanning drilling. We demonstrate that virgin PI films provide a suitable environment for the mobility, proliferation and intercellular communication of human bone marrow mesenchymal stem cells, and discuss how cell behaviour varies on the micro-machined PI films with holes of different diameters (3.1, 8.4 and 16.7 μm) and hole spacing (30, 35, 40 and 45 μm). We conclude that the holes of 3.1 μm diameter were sufficient for metabolic and genetic communication through membranous tunneling tubes between cells residing on the opposite sides of PI film, but prevented the trans-migration of cells through the holes. Copyright © 2016 John Wiley & Sons, Ltd.

Dot-Matrix Hologram Rendering Algorithm and its Validation through Direct Laser Interference Patterning

“…The laser pulse picker, optical intensity attenuation, the control of interfering laser beams, and sample translation—all were implemented by employing a FemtoLab (Vilnius, Lithuania, Altechna R&D) laser workstation. More detailed information about the setup can be found in 50 , 51 . Dot-matrix hologram images were imposed by positioning the sample using XYZ translation stages (Pittsburgh, PA, USA, Aerotech) controlled via SCA software (Vilnius, Lithuania, Altechna R&D).…”

Tunneling Nanotubes and Gap Junctions–Their Role in Long-Range Intercellular Communication during Development, Health, and Disease Conditions

“…For example, during the stroke, ischemia and reperfusion conditions regulating the formation of TNTs may provide a means of cell rescue. Furthermore, TNTs offer a novel delivery route for stem-cell based therapies against genetic conditions resulting in organelle dysfunction (Bruzauskaite et al, 2016 ; Antanavičiūtė et al, 2017 ) and for chemotherapeutic drugs that disrupt DNA replication, such as nucleoside analogs (Bruzauskaite et al, 2016 ; Antanavičiūtė et al, 2017 ). A study by Lou demonstrated that TNTs could facilitate the intercellular spread of therapeutic oncolytic viral vectors; furthermore, TNTs also mediated the bystander effect by facilitating distribution of therapeutic drugs (nucleoside analogs) activated by viral thymidine kinase.…”

“…A study by Lou demonstrated that TNTs could facilitate the intercellular spread of therapeutic oncolytic viral vectors; furthermore, TNTs also mediated the bystander effect by facilitating distribution of therapeutic drugs (nucleoside analogs) activated by viral thymidine kinase. The study establishes TNTs as an alternate route, beyond gap junctions, for cells to amplify the effects of potential disease-targeting drugs, opening a new door to harnessing TNTs as potential cellular conduits for drug delivery (Bruzauskaite et al, 2016 ; Antanavičiūtė et al, 2017 ). Conversely, where infectious agents ‘hijack’ TNTs to spread their pathology, blocking TNTs by targeting specific TNT components could represent another therapeutic strategy in disease.…”

Evaluation of Preosteoblast MC3T3-E1 Cells Cultured on a Microporous Titanium Membrane Fabricated Using a Precise Mechanical Punching Process

“…Cells migrate into micropores when cultivated, and are more likely to localize around square holes. Therefore, increases in cell numbers may be slightly smaller on the flat surface areas on the head side than on a control material [33]. In our previous studies on the functions of preosteoblast MC3T3-E1 cells cultured on a microporous Ti membrane, cells maintained basic survival in growth medium supplemented with 2% FBS, and the growth rate was very slow, which was suitable for long-term observations of the morphological structure of cells (30 continuous days) by scanning electron microscopy (SEM).…”