Nanosecond laser ablation enhances cellular infiltration in a hybrid tissue scaffold

•A simple laser ablation process was optimized to fabricate microchannels in a polymer-tissue scaffold.•The laser micropatterning process selectively ablated a part of polymer layer.•Ablated scaffolds demonstrated adequate structural, thermal, and mechanical properties.•Lastly, ablated scaffolds exhibited enhanced cellular colonization in the microchannels.

Hybrid tissue engineered (HTE) scaffolds constituting polymeric nanofibers and biological tissues have attractive bio-mechanical properties. However, they suffer from small pore size due to dense overlapping nanofibers resulting in poor cellular infiltration. In this study, using nanosecond (ns) laser, we fabricated micro-scale features on Polycaprolactone (PCL)-Chitosan (CH) nanofiber layered bovine pericardium based Bio-Hybrid scaffold to achieve enhanced cellular adhesion and infiltration. The laser energy parameters such as fluence of 25 J/cm2, 0.1 mm instep and 15 mark time were optimized to get structured microchannels on the Bio-Hybrid scaffolds. Laser irradiation time of 40 μs along with these parameters resulted in microchannel width of ~ 50 μm and spacing of ~ 35 μm between adjacent lines. The biochemical, thermal, hydrophilic and uniaxial mechanical properties of the Bio-Hybrid scaffolds remained comparable after laser ablation reflecting extracellular matrix (ECM) stability. Human umbilical cord mesenchymal stem cells and mouse cardiac fibroblasts seeded on these laser-ablated Bio-Hybrid scaffolds exhibited biocompatibility and increased cellular adhesion in microchannels when compared to non-ablated Bio-Hybrid scaffolds. These findings suggest the feasibility to selectively ablate polymer layer in the HTE scaffolds without affecting their bio-mechanical properties and also describe a new approach to enhance cellular infiltration in the HTE scaffolds.

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