Modular scaffolds assembled around living cells using poly(ethylene glycol) microspheres with macroporation via a non-cytotoxic porogen

Evan A. Scott, Michael D. Nichols, Rebecca Kuntz-Willits, Donald L. Elbert*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Modular, bioactive, macroporous scaffolds were formed by crosslinking poly(ethylene glycol) (PEG) microspheres around living cells. Hydrogel microspheres were produced from reactive PEG derivatives in aqueous sodium sulfate solutions without the use of surfactants or copolymers. Microspheres were formed following thermally induced phase separation if the gel point was reached prior to extensive coarsening of the PEG-rich domains. Three types of PEG microspheres with different functionalities were used to form scaffolds: one type provided mechanical support, the second type provided controlled delivery of the angiogenesis-promoting molecule, sphingosine 1-phosphate (S1P) and the third type served as a slowly dissolving non-cytotoxic porogen. Scaffolds were formed by centrifuging microspheres in the presence of HepG2 hepatoma cells, resulting in a homogenous distribution of cells. During overnight incubation at 37 °C, the microspheres reacted with serum proteins in cell culture medium to stabilize the scaffolds. Within 2 days in culture, macropores formed due to the dissolution of the porogenic PEG microspheres, without affecting cell viability. Gradients in porosity were produced by varying the buoyancy of the porogenic microspheres. Conjugated RGD cell adhesion peptides and the delivery of S1P promoted endothelial cell infiltration through macropores in the scaffolds. The scaffolds presented here differ from previous hydrogel scaffolds in that: (i) cells are not encapsulated in hydrogel; (ii) macropores form in the presence of cells; and (iii) scaffold properties are controlled by the modular assembly of different microspheres that perform distinct functions.

Original languageEnglish (US)
Pages (from-to)29-38
Number of pages10
JournalActa Biomaterialia
Issue number1
StatePublished - Jan 2010


  • Hydrogel
  • LCST
  • Modular scaffold
  • Poly(ethylene glycol)
  • Tissue engineering

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Biotechnology
  • Biomedical Engineering
  • Biomaterials


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