Femtosecond Laser Fabrication of Engineered Functional Surfaces Based on Biodegradable Polymer and Biopolymer/Ceramic Composite Thin Films

Abstract

Surface functionalization introduced by precisely-defined surface structures depended on the surface texture and quality. Laser treatment is an advanced, non-contact technique for improving the biomaterials surface characteristics. In this study, femtosecond laser modification was applied to fabricate diverse structures on biodegradable polymer thin films and their ceramic blends. The influences of key laser processing parameters like laser energy and a number of applied laser pulses (N) over laser-treated surfaces were investigated. The modification of surface roughness was determined by atomic force microscopy (AFM). The surface roughness (Rrms) increased from approximately 0.5 to nearly 3 µm. The roughness changed with increasing laser energy and a number of applied laser pulses (N). The induced morphologies with different laser parameters were compared via Scanning electron microscopy (SEM) and confocal microscopy analysis. The chemical composition of exposed surfaces was examined by FTIR, X-ray photoelectron spectroscopy (XPS), and XRD analysis. This work illustrates the capacity of the laser microstructuring method for surface functionalization with possible applications in improvement of cellular attachment and orientation. Cells exhibited an extended shape along laser-modified surface zones compared to non-structured areas and demonstrated parallel alignment to the created structures. We examined laser-material interaction, microstructural outgrowth, and surface-treatment effect. By comparing the experimental results, it can be summarized that considerable processing quality can be obtained with femtosecond laser structuring.

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition

“…Similar results were described for other polymer types. Femtosecond laser treatment favorably influenced attachment and orientation of mouse calvaria osteoblasts and human adipose derived mesenchymal stem cells on thin films of pure chitosan and composite blends of chitosan (Ch)/HAp/ZrO 2 [ 62 ]. The authors of another work [ 83 ] studied human osteoblasts ATCC cultured on the surface of poly(L-lactide)/hydroxyapatite films modified using femtosecond laser and did not detect any cytotoxicity.…”

“…and adapt structural and physical properties of film surface to cell engineering applications. Daskalova et al [ 62 ] reported using femtosecond laser modification to produce various structures of thin films of biodegradable polymers and their ceramic blends (pure chitosan thin films and different percentage of composite blends of chitosan (Ch)/HAp/ZrO 2 thin films). Laser treatment increased film surface roughness and enhanced attachment and orientation of eukaryotic cells.…”

“…Analysis of the most recent published studies, including a thorough review by Professor Ravi-Kumar et al [ 58 ], key experimental works [ 28 , 48 , 54 , 55 ], and the latest studies [ 56 , 57 , 58 , 59 , 61 , 62 ] has provided the basis for summarizing the currently available data and existing notions of the effects produced by laser treatment of polymer materials. Laser ablation is widely used today to treat various materials (metals, ceramics, glass, and polymers).…”

Biomimetic Hierarchical Structuring of PLA by Ultra-Short Laser Pulses for Processing of Tissue Engineered Matrices: Study of Cellular and Antibacterial Behavior

“…Ortiz et al reported that the laser ablation of poly-L-lactic acid (PLLA) is governed by a multi-photon process in the three cases of interaction: with the fundamental (1064 nm), the second (532 nm) and the third harmonic generation wave (355 nm) of Nd: YVO 4 laser [ 65 ]. The group of Daskalova et al, for example, achieved 3D porous structures composed of µm-sized porous foam on the surface of collagen, elastin and chitosan thin films by femtosecond laser structuring at ƛ = 800 nm in which cells adhere, elongate, and orientate [ 66 , 67 , 68 ].…”

Polystyrene Thin Films Nanostructuring by UV Femtosecond Laser Beam: From One Spot to Large Surface

“…Considering the laser regime in the literature, femtosecond beams are less employed for polymer-thin-films processing [ 41 , 42 ], and particularly with UV beams, as investigated in the present work. The advantage of the femtosecond (fs) regime compared to the nanosecond one is that the LIPSS could be formed despite the low absorption coefficient of the polymers [ 43 ].…”