Preparation of stem cell aggregates with gelatin microspheres to enhance biological functions

Abstract

The objective of this study is to improve the viability and osteogenic differentiation of cultured rat bone marrow-derived mesenchymal stem cells (MSC) by the use of gelatin hydrogel microspheres. Gelatin was dehydrothermally crosslinked at 140° C for 48 h in a water in oil emulsion state. When cultured with the gelatin hydrogel microspheres in round, U-bottomed wells of 96-well plates coated with poly(vinyl alcohol) MSC formed aggregates homogeneously incorporating the microspheres. The viability of the cell aggregates was significantly higher compared with that of aggregates formed without microspheres. MSC proliferation in the aggregates depended on the number and diameter of the incorporated microspheres. Higher MSC proliferation was observed for aggregates incorporating a greater number of larger gelatin microspheres. When evaluated as a measure of aerobic glycolysis the ratio of l-lactic acid production/glucose consumption in MSC was significantly lower for MSC cultured with gelatin microspheres than those without microspheres. MSC production of alkaline phosphatase (ALP) and sulfated glycosaminaglycan (sGAG) was examined to evaluate their potential osteogenic and chondrogenic differentiation. The amount of ALP produced was significantly higher for MSC aggregates cultured with gelatin microspheres than that of MSC cultured without microspheres. On the other hand, the amount of sGAG produced was significantly lower for MSC aggregates containing microspheres. It is concluded that the incorporation of gelatin hydrogel microspheres prevents the aggregated MSC suffering from a lack of oxygen, resulting in enhanced MSC aggregation and cell proliferation and osteogenic differentiation.

Cellular Self-Assembly with Microsphere Incorporation for Growth Factor Delivery Within Engineered Vascular Tissue Rings

“…Others have reported increases in tissue strength and stiffness with gelatin microsphere incorporation, 13,21 which may be due to improved oxygen and nutrient diffusion in dense tissues. 16,42 The decrease in ring MTM was unexpected, as microsphere incorporation has been shown to increase tissue stiffness. 21,43 However, microspheres in this experiment appear to be degraded by 14 days and may no longer be directly contributing to stiffness.…”

“…13 Cellular self-assembly may have advantages over scaffold-based approaches for vascular tissue engineering. Compared to cells seeded on scaffold materials, selfassembled cellular constructs may have greater cell density, enhanced extracellular matrix (ECM) production and tissue strength, improved biological function, and lower susceptibility to degradation and infection, 11,[14][15][16] and thus may be more similar in structure and function to native tissue. However, existing methods for fabricating self-assembled blood vessels create homogenous tubes not conducive to creating focal heterogeneities characteristic of certain diseases such as aneurysm or intimal hyperplasia.…”

An Artificial Silk-elastin-like Protein Suppresses Cells Adhesion without Apoptosis

“…There have been reported on some materials which have the potential to suppress the cell adhesion to form cell aggregates (spheroids) [8][9][10][11][12][13][14][15]. It is well recognized that once detached from the substrate to adhere, cells are normally programmed to die due to their activation of apoptosis pathway [16].…”

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“…Recently, some natural and chemosynthetic biodegradable materials have been introduced to injectable microsphere technique; for examples, gelatin 14 hemoglobin 15 , polycarbonate 16 , polyamino acid 17 , polylactic acid (PLA) 18 , polylactic-co-glycolic acid (PLGA) 19 , and some segmented copolymers 20,21 . In above-mentioned materials, PLA and PLGA were approved to use as biomedical material for its biodegradability in vivo by FDA and were successfully used in loading tprotein/peptide drugs [22][23][24] .…”