This study presents a new innovative method where electrospinning is used to coat single microfibers with nanofibers. The nanofiber-coated microfibers can be formed into scaffolds with the combined benefits of tailored porosity for cellular infiltration and nanostructured surface morphology for cell growth. The nanofiber coating is obtained by using a grounded collector rotating around the microfiber, to establish an electrical field yet allow collection of nanofibers on the microfiber. A Teflon tube surrounding the fibers and collector is used to force the nanofibers to the microfiber. Polycaprolactone nanofibers were electrospun onto polylactic acid microfibers and scaffolds of 95 and 97% porosities were made. Human chondrocytes were seeded on these scaffolds and on reference scaffolds of purely nanofibers and microfibers. Thereafter, cellular infiltration was investigated. The results indicated that scaffold porosity had great effects on cellular infiltration, with higher porosity resulting in increased infiltration, thereby confirming the advantage of the presented method.

Regeneration of articular cartilage damage is an area of great interest due to the limited ability of cartilage to self-repair. The latest cartilage repair strategies are dependent on access to biomaterials to which chondrocytes can attach and in which they can migrate and proliferate, producing their own extracellular matrix. In the present study, engineered porous bacterial cellulose (BC) scaffolds were prepared by fermentation of Acetobacter xylinum (A. xylinum) in the presence of slightly fused wax particles with a diameter of 150-300 microm, which were then removed by extrusion. This porous material was evaluated as a scaffold for cartilage regeneration. Articular chondrocytes from young adult patients as well as neonatal articular chondrocytes were seeded with various seeding techniques onto the porous BC scaffolds. Scanning electron microscopy (SEM) analysis and confocal microscopy analysis showed that cells entered the pores of the scaffolds and that they increasingly filled out the pores over time. Furthermore, DNA analysis implied that the chondrocytes proliferated within the porous BC. Alcian blue van Gieson staining revealed glycosaminoglycan (GAG) production by chondrocytes in areas where cells were clustered together. With some further development, this novel biomaterial can be a suitable candidate for cartilage regeneration applications.