Influence of soluble PEG-OH incorporation in a 3D cell-laden PEG-fibrinogen (PF) hydrogel on smooth muscle cell morphology and growth

We have been able to control hydrogel compliance and cell spreading in a three-dimensional (3D) cell-laden system (hydrogel) using soluble PEG-OH. This was accomplished by encapsulating smooth muscle cells (SMCs) into poly(ethylene glycol)-fibrinogen (PEG-fibrinogen or PF) with poly(ethylene glycol)-diol (PEG-OH) as a macromolecular leachant. The cell-encapsulating hydrogels were prepared with three concentrations of soluble PEG-OH having a mass of 10 kDa (1, 5 and 10% w/v). Rheology was used to measure the elastic (storage) component of the complex shear modulus of these hydrogels, while quantitative morphometrics were used to characterize SMC morphology. PF hydrogel with a higher amount of PEG-OH displayed a lower storage modulus and a higher elongated cell morphology of SMCs. Structural changes of PF hydrogels mainly owing to gelation-induced phase separation imparted by the soluble PEG-OH in 3D cell-laden hydrogels dramatically affected both the properties of the hydrogel network including the modulus as well as cell spreading.