Body-Shaping Membrane to Regenerate Breast Fat by Elastic Structural Holding

Tissue regeneration requires structural holding and movement support using tissue-type-specific aids such as bone casts,skin bandages,and joint protectors.Currently,an unmet need exists in aiding breast fat regeneration as the breast moves following continuous body motion by exposing the breast fat to dynamic stresses.Here,the concept of elastic structural holding is applied to develop a shape-fitting moldable membrane for breast fat regeneration(“adipoconductive”)after surgical defects are made.The membrane has the following key characteristics:(a)It contains a panel of honeycomb structures,thereby efficiently handling motion stress through the entire membrane;(b)a strut is added into each honeycomb in a direction perpendicular to gravity,thereby suppressing the deformation and stress concentration upon lying and standing;and(c)thermo-responsive moldable elastomers are used to support structural holding by suppressing large deviations of movement that occur sporadically.The elastomer became moldable upon a temperature shift above T_(m).The structure can then be fixed as the temperature decreases.As a result,the membrane promotes adipogenesis by activating mechanotransduction in a fat miniature model with pre-adipocyte spheroids under continuous shaking in vitro and in a subcutaneous implant placed on the motion-prone back areas of rodents in vivo.

Influence of viscosity on chondrogenic differentiation of mesenchymal stem cells during 3D culture in viscous gelatin solution-embedded hydrogels

Differentiation of human bone marrow-derived mesenchymal stem cells(hMSCs)is regulated by a variety of cues of their surrounding microenvironments.In particular,mechanical properties of cell culture matrices have been recently disclosed to play a pivotal role in stem cell differentiation.However,it remains elusive how viscosity affects the chondrogenic differentiation of hMSCs during three-dimensional(3 D)culture.In this study,a 3 D culture system that was established by embedding viscous gelatin solution in chemically cross-linked gelatin hydrogels was used for 3 D culture of hMSCs in gelatin solutions with different viscosities.The influence of solution viscosity on chondrogenic differentiation of hMSCs was investigated.Viscous gelatin solutions promoted cell proliferation in the order of low,middle and high viscosity while elastic hydrogels restricted cell proliferation.High viscosity gelatin solution led to increased production of the cartilaginous matrix.Under the synergistic stimulation of chondrogenic induction factors,high viscosity was beneficial for the chondrogenic differentiation of hMSCs.The results suggested the role of viscosity should be considered as one of the dominant mechanical cues affecting stem cell differentiation.