Descrição
The present work studies the influence of hydrolytic enzymes (a-amylase or lipase) on the degradation of fiber
mesh scaffolds based on a blend of starch and poly(e-caprolactone) (SPCL) and the osteogenic differentiation of
osteogenic medium–expanded rat bone marrow stromal cells (MSCs) and subsequent formation of extracellular
matrix on these scaffolds under static culture conditions. The biodegradation profile of SPCL fiber meshes was
investigated using enzymes that are specifically responsible for the enzymatic hydrolysis of SPCL using concentrations
similar to those found in human serum. These degradation studies were performed under static and
dynamic conditions. After several degradation periods (3, 7, 14, 21, and 30 days), weight loss measurements and
micro-computed tomography analysis (specifically porosity, interconnectivity, mean pore size, and fiber thickness)
were performed. The SPCL scaffolds were seeded with rat MSCs and cultured for 8 and 16 days using
complete osteogenic media with and without enzymes (a-amylase or lipase). Results indicate that culture medium
supplemented with enzymes enhanced cell proliferation after 16 days of culture, whereas culture medium
without enzymes did not. No calcium was detected in groups cultured with a-amylase or without enzymes after
each time period, although groups cultured with lipase presented calcium deposition after the eighth day,
showing a significant increase at the sixteenth day. Lipase appears to positively influence osteoblastic differentiation
of rat MSCs and to enhance matrix mineralization. Furthermore, scanning electron microscopy images
showed that the enzymes did not have a deleterious effect on the three-dimensional structure of SPCL fiber
meshes, meaning that the scaffolds did not lose their structural integrity after 16 days. Confocal micrographs
have shown cells to be evenly distributed and infiltrated within the SPCL fiber meshes up to 410 mm from the
surface. This study demonstrates that supplementation of culture media with lipase holds great potential for the
generation of bone tissue engineering constructs from MSCs seeded onto SPCL fiber meshes, because lipase
enhances the osteoblastic differentiation of the seeded MSCs and promotes matrix mineralization without
harming the structural integrity of the meshes over 16 days of culture.
; Pham, Q. P. 
