Annals of Biomedical Engineering

, Volume 46, Issue 8, pp 1146–1159 | Cite as

Cell Mimicking Microparticles Influence the Organization, Growth, and Mechanophenotype of Stem Cell Spheroids

  • Nicholas R. Labriola
  • Jessica S. Sadick
  • Jeffrey R. Morgan
  • Edith Mathiowitz
  • Eric M. DarlingEmail author


Substrate stiffness is known to alter cell behavior and drive stem cell differentiation, though most research in this area has been restricted to traditional, two-dimensional culture systems rather than more physiologically relevant, three-dimensional (3D) platforms. In this study, we utilized polymer-based, cell mimicking microparticles (CMMPs) to deliver distinct, stable mechanical cues to human adipose derived stem cells in 3D spheroid culture to examine changes in adipogenic differentiation response and mechanophenotype. After 21 days of adipogenic induction, spheroids containing CMMPs (composite spheroids) stiffened in accordance with CMMP elasticity such that spheroids containing the stiffest, ~ 10 kPa, CMMPs were over 27% stiffer than those incorporating the most compliant, ~ 0.25 kPa CMMPs. Adipogenically induced, cell-only spheroids were over 180% larger and 50% more compliant than matched controls. Interestingly, composite spheroids cultured without chemical induction factors dissociated when presented with CMMPs stiffer than ~ 1 kPa, while adipogenic induction factors mitigated this behavior. Gene expression for PPARG and FABP4 were upregulated more than 45-fold in adipogenically induced samples compared to controls but were unaffected by CMMP elasticity, attributed to insufficient cell-CMMP contacts throughout the composite spheroid. In summary, mechanically tuned CMMPs influenced whole-spheroid mechanophenotype and stability but minimally affected differentiation response.


Stem cell differentiation Adipogenesis Elastic and viscoelastic properties 3D spheroid culture Self-assembly Atomic force microscopy (AFM) Hyper-compliant microparticles Tissue engineering 



Atomic force microscopy


Ammonium persulfate


Adipose derived stem cells


Cell mimicking microparticle


Young’s modulus/elastic modulus


Relaxed modulus


Instantaneous modulus


Fatty acid binding protein 4






Phosphate buffered saline


Peroxisome proliferator-activated receptor gamma




Apparent viscosity







The authors would like to thank Manisha K. Shah for her assistance with confocal imaging. This work was supported by awards from the National Institute of General Medical Sciences (EMD, P20 GM104937), National Institute of Arthritis and Musculoskeletal and Skin Diseases (EMD, R01 AR063642), and the National Science Foundation (EMD, CAREER Award, CBET1253189). The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Science Foundation or National Institutes of Health.

Conflict of interest

NRL, EM, and EMD have patent filings relevant to the technology in this study. EMD owns MimicSphere, LLC, which focuses on the same technology.

Author Contributions

NRL and EMD designed the study. NRL performed all CMMP/substrate preparation, cell culture, mechanical testing, and imaging. NRL, EMD, and JSS analyzed the data. NRL, EMD, JSS, JRM, and EM wrote and edited the manuscript. JRM and EM provided materials and consultation on the design, execution, and interpretation of the experiment and data sets.

Supplementary material

10439_2018_2028_MOESM1_ESM.pdf (1.5 mb)
Supplementary material 1 (PDF 1507 kb)


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Copyright information

© Biomedical Engineering Society 2018

Authors and Affiliations

  • Nicholas R. Labriola
    • 1
  • Jessica S. Sadick
    • 2
  • Jeffrey R. Morgan
    • 1
    • 2
    • 3
  • Edith Mathiowitz
    • 1
    • 2
    • 3
  • Eric M. Darling
    • 1
    • 2
    • 3
    • 4
    Email author
  1. 1.Center for Biomedical EngineeringBrown UniversityProvidenceUSA
  2. 2.Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceUSA
  3. 3.School of EngineeringBrown UniversityProvidenceUSA
  4. 4.Department of OrthopaedicsBrown UniversityProvidenceUSA

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