Introduction: The demand for implants is continuously increasing, among other things, due to the aging of the population [1]. A biomaterial should provide an environment for cells that is desirable for tissue regeneration. Ideally, a biomaterial promotes cell adhesion, growth, and function [2]. Biomaterials design considerations are chemical [3,4] as well as surface architecture (topography, topology) [5] modifications [6]. It is known that cells transmit external signals into the interior via receptors or ion channels [2,5,7]. Our motivation is to assess and understand innovative medical materials from various biomaterials that promote tissue regeneration. Depending on the replacement, different materials were analysed for bone ingrowth, such as titanium coatings. These studies focused on the correlation of physico-chemical properties of different surfaces and cell adhesion.

Experimental: Irradiation with an ultrashort pulse laser was applied for creating different nano- and microstructures of titanium alloy (Ti6Al4V) [8] and medical steel due to varied laser parameters (e.g., pulse energy, line overlap, and procedure of laser passage). The cold atmospheric pressure plasma jet kINPen®09 (Neoplas Tools GmbH) was used for chemical surface designing with Argon gas [3]. We tested the hydrophilicity by evaluating water contact angles (WCA), area surface roughness (Sa), and profile. The cellular adhesion, morphology, and physiology of human MG-63 osteoblasts and HaCaT keratinocytes were studied by scanning electron microscopy (SEM), flow cytometry, confocal laser scanning microscopy (LSM), and microplate reader within 24 hours.

Results: Micromachining by ultrashort pulse laser was well suited for micro-roughening and created different micro-and nanostructures due to different laser settings. On the laser-structured materials, adapted cell behaviour could be observed that varied according to topographical motifs. On very rough microstructures with deep cavities, cell growth and spreading were inhibited. A beneficial cellular response to nano-structuring and sinusoidal micro-structuring could be demonstrated regardless of hydrophilicity (Fig. 1). Interestingly, plasma increased surface hydrophilicity and consequently promoted cell adhesion, occupation, and growth on laser-structured materials. At the same time, the plasma-treated surface induced an increase in intracellular calcium ions. A rapid cellular acceptance of biomaterials in the tissue is a critical factor for integration for permanent implants.

Conclusion: An ultrashort pulse laser is a powerful tool for biomaterial surface modification, and the additional treatment with plasma improves the wettability and cell adhesion. Cell biological studies are necessary to better understanding and evaluate of innovative medical materials and their interplay with the surrounding biosystem.