The use of hybrid manufacturing to produce bimodal scaffolds has represented a great advancement in tissue engineering. These scaffolds provide a favorable environment in which cells can adhere and produce new tissue. However, there are several areas of opportunity to manufacture structures that provide enough strength and rigidity, while also improving chemical integrity. As an advancement in the manufacturing process of scaffolds, a cooling system was introduced in a fused deposition modeling (FDM) machine to vary the temperature on the printing bed. Two groups of polylactic acid (PLA) scaffolds were then printed at two different bed temperatures. The rate of degradation was evaluated during eight weeks in Hank’s Balanced Salt Solution (HBSS) in a controlled environment (37 °C–120 rpm) to assess crystallinity. Results showed the influence of the cooling system on the degradation rate of printed scaffolds after the immersion period. This phenomenon was attributable to the mechanism associated with alkaline hydrolysis, where a higher degree of crystallinity obtained in one group induced greater rates of mass loss. The overall crystallinity was observed, through differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FTIR) analysis, to increase with time because of the erosion of some amorphous parts after immersion.

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Background. While there are clear recommendations for the technique and suture material for abdominal fascial closure, surgeons may have personal preferences arising from prevoius experiences or influenced during training. The decision of which suture material to use should not influence the outcome of fascial closure. The objective of this study is to analyze the influence of time and tension on the mechanical properties of sutures used for abdominal fascial closure. Methods. Polyglactin 910, polypropylene, and polydioxanone sutures were exposed to 8 and 10 newtons of constant tensile strain during a period of 7 and 14 days. They were then mechanically tested to assess changes in their properties regarding strength and deformation. Results. No significant changes were observed in maximum tensile force or extension within the different suture groups. Regarding deformation, polypropylene and polydioxanone did not exhibit alterations in their curve behavior, while polyglactin 910 did exhibit changes compared to the control group, as seen by the elevation in its Young modulus when manipulated. Conclusions. Our study finds that while different sutures behave differently, nor time or tension have a negative effect on their biomechanical resilience and can withstand tensile strengths well above any physiological or pathological condition.

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