Full Length Article In vitro behavior of human mesenchymal stem cells on poly(N-isopropylacrylamide) based biointerfaces obtained by matrix assisted pulsed laser evaporation Madalina Icriverzi a,b,1 , Laurentiu Rusen c,1 , Livia Elena Sima a , Antoniu Moldovan c , Simona Brajnicov c,d , Anca Bonciu c,e , Natalia Mihailescu c , Maria Dinescu c , Anisoara Cimpean b , Anca Roseanu a,⇑ , Valentina Dinca c,⇑ a Institute of Biochemistry, Romanian Academy, 296 Splaiul Independentei, Bucharest, Romania b University of Bucharest, Faculty of Biology, Splaiul Independentei 91-95, Bucharest R-050095, Romania c National Institute for Lasers, Plasma and Radiation Physics, Atomistilor 409, 077125 Magurele, Bucharest, Romania d University of Craiova, Faculty of Mathematics and Natural Sciences, RO-200585 Craiova, Romania e University of Bucharest, Faculty of Physics, RO-077125 Magurele, Romania article info Article history: Received 8 August 2017 Revised 7 January 2018 Accepted 23 January 2018 Keywords: pNIPAM coatings MAPLE Mesenchymal stem cells abstract The use of smart coatings with tunable characteristics in bioengineering fields is directly correlated with the surface chemical and topographical properties, the method of preparation, and also with the type of cells implied for the specific application. In this work, a versatile surface modification technique based on the use of lasers (Matrix-Assisted Pulsed Laser Evaporation (MAPLE)) was used to yield poly(N-isopropylacrylamide) (pNIPAM) and its derivatives (amine, azide and amide terminated pNIPAM) functional and termoresponsive thin films. Surface properties of pNIPAM and its derivative films such as morphology, roughness and hydrophobic/hydrophilic character, as well as the thermoresponsive capacity were investigated by atomic force microscopy and contact angle measurements. The chemical characteristics of the pNIPAM based thin films were analysed by Fourier Transform Infrared Spectroscopy (FTIR). The chemical functionality was kept for all the samples obtained by MAPLE and the thermoresponse was demonstrated by the change in the contact angle and thickness values when the temperature was shifted from 37 °C to 24 °C for all the materials tested, with a smaller change for mal- eimide terminated pNIPAM. Biological assays performed in vitro (fluorescence microscopy and Scanning Electron Microscopy (SEM)) confirmed the conditioning of the early mesenchymal stem cell (MSC) growth by specific chemistry of the coatings. The cell imaging analysis revealed no cytotoxic effect of pNIPAM surfaces irrespective of type of functionalization. An increased proliferation rate of the cells grown on pNIPAM-azide surfaces and a lower cell density on pNIPAM-maleimide surfaces compared to the pNIPAM surfaces was observed, which can direct their use to potential surfaces in regenerative medicine approaches. Ó 2018 Elsevier B.V. All rights reserved. 1. Introduction A key strategy for the development of high-performance bioma- terials useful in regenerative medicine is to provide controlled and tunable smart interfacial properties able to modulate the response of target cells. Since the initial synthesis of temperature-responsive surfaces of poly (N-isopropylacrylamide) (pNIPAM) in 1986, its peculiar characteristic on reversible phase transition behavior (i.e. the collapse of the swollen polymer matrix for a temperature above the lower critical solution temperature (LCST) in an aqueous solution) and temperature response closed to human body, led to an increased interest for developing methods for preparation, char- acterization and especially application of these types of materials as sensors, drug delivery vehicles smart systems or tissue engi- neering constructs [1–12]. Because of its restricted application in tissue engineering due to the poor capacity to support cell adhesion, various aspects related https://doi.org/10.1016/j.apsusc.2018.01.200 0169-4332/Ó 2018 Elsevier B.V. All rights reserved. ⇑ Corresponding authors. E-mail addresses: roseanua@gmail.com (A. Roseanu), valentina.dinca@inflpr.ro (V. Dinca). 1 LR and MI contributed equally to this work. Applied Surface Science 440 (2018) 712–724 Contents lists available at ScienceDirect Applied Surface Science journal homepage: www.elsevier.com/locate/apsusc