Royal Society of ChemistryAreias, A.; Ribeiro, C.; Sencadas, V.; Garcia Giralt, N.; Diez Perez, A.; Gómez Ribelles, JL.; Lanceros Mendez, S. (2012). Influence of crystallinity and fiber orientation on hydrophobicity and biological response of poly(L-lactide) electrospun mats. Soft Matter. 8 (21) AbstractPoly(L-lactide) electrospun mates have been produced with random and aligned fiber orientation and degrees of crystallinity from 0 up to nearly 50%. These two factors, fiber alignment and degree of crystallinity strongly affect the hydrophobicity of the samples, being this larger for the aligned fiber mats and for the fibers with higher degree of crystallinity. Whereas the first effect can be associated to a decrease in the degree of porosity the second should be related to variations in the fiber roughness at nanometric scale and an increase in fiber stiffness. Proliferation of human chondrocytes cultured in monolayer on these substrates is similar in both aligned and non-aligned amorphous mats. Crystallization of the aligned mats, on the other hand, nearly suppresses proliferation and the cells produce higher amounts of aggrecan, characteristic of the extracellular matrix of hyaline cartilage.

18The production of chitosan nanofiber mats by electrospinning presents serious 19 difficulties due to the lack of suitable solvents and the strong influence of processing were the parameters considered in this study.

Poly(l-lactide) electrospun mats with random and aligned fiber orientation and films have been produced with degrees of crystallinity ranging from 0 up to nearly 50%. The overall surface roughness is practically constant irrespective of the sampling areas (1 × 1 µm to 20 × 20 µm) for degrees of crystallinity below 30%, increasing for higher degrees of crystallinity for the larger sampling areas. Further, due to fiber confinement, surface roughness variations are smaller in electrospun mats. Samples with 50% of crystallinity show the lowest osteoblast and the highest fibroblast proliferation. Therefore, it is verified that higher roughness promotes lower osteoblast but higher fibroblast proliferation. The overall results indicate the relevant role of the sub-microenvironment variations associated to the microscale roughness in determining the different cell responses.

Digital solutions have emerged as an alternative to conventional physiotherapy, particularly for chronic musculoskeletal pain (CMP) management; however, its long-term effects remain largely unexplored. This study focuses on patients reporting CMP, assessing 1-year clinical outcomes after a multimodal digital care program (DCP) versus non-participants, who enrolled in the program but never engaged in a single exercise session or partook of the educational content made available to them. In this longitudinal study ad-hoc analysis, pain and functionality outcomes at 1-year reassessment were studied, focusing on the odds of reaching minimal clinically important difference (MCID) and, overall average reduction in both outcomes. Healthcare utilization was additionally studied within the same period. From 867 individuals allocated to the study, 460 completed the 1-year reassessment (intervention group: 310; comparison group: 150). The intervention group presented sustained and greater pain reduction until 1-year reassessment than the comparison group, reflecting greater odds ratio of achieving the MCID both in pain and functionality (1.90 95% CI: 1.27–2.86, p = 0.002 and 2.02 95% CI: 1.31–3.12, p = 0.001, respectively). A lower healthcare utilization during the 1-year follow-up was observed in the intervention group than in the comparison group. This study suggests that a digital CMP program may have a lasting impact on improved pain and functionality in patients with CMP.

Electrospun chitosan nanofiber mats have been obtained using chitosan solutions in a mixture of trifluoroacetic acid and dichloromethane. The relationship between processing parameters (solvent composition, polymer concentration in the solution, feeding rate, applied voltage, travelling distance between the needle and the collector) and fiber morphology was studied. Taguchi's methodology was followed to determine which parameters have the strongest influence on mean fiber diameter and fiber homogeneity. Chitosan nanofibers obtained with this procedure were water soluble due to the protonation of amine side groups but were successfully neutralized by immersion in calcium carbonate solutions. It was established that fiber diameter is mainly determined by the solution concentration and the distance from the needle to the collector while other parameters have less influence. The set of parameters that produce the thinnest fibers were a concentration of 8 wt%, a TFA/DCM ratio of 80:20 (v/v %), a voltage of 30 kV, a flow rate of 6.0 mL/h, a gap distance of 10 cm, using a needle diameter of 0.5, allowing to produce randomly oriented mats with a mean fiber thickness of 66 nm.