Cartilage-like mechanical properties of poly (ethylene glycol)-diacrylate hydrogels

Abstract

Hydrogels prepared from poly-(ethylene glycol) (PEG) have been used in a variety of studies of cartilage tissue engineering. Such hydrogels may also be useful as a tunable mechanical material for cartilage repair. Previous studies have characterized the chemical and mechanical properties of PEG-based hydrogels, as modulated by precursor molecular weight and concentration. Cartilage mechanical properties vary substantially, with maturation, with depth from the articular surface, in health and disease, and in compression and tension. We hypothesized that PEG hydrogels could mimic a broad range of the compressive and tensile mechanical properties of articular cartilage. The objective of this study was to characterize the mechanical properties of PEG hydrogels over a broad range and with reference to articular cartilage. In particular, we assessed the effects of PEG precursor molecular weight (508 Da, 3.4 kDa, 6 kDa, and 10 kDa) and concentration (10–40%) on swelling property, equilibrium confined compressive modulus (HA0), compressive dynamic stiffness, and hydraulic permeability (kp0) of PEG hydrogels in static/dynamic confined compression tests, and equilibrium tensile modulus (Eten) in tension tests. As molecular weight of PEG decreased and concentration increased, hydrogels exhibited a decrease in swelling ratio (31.5–2.2), an increase in HA0 (0.01–2.46 MPa) and Eten (0.02–3.5 MPa), an increase in dynamic compressive stiffness (0.055–42.9 MPa), and a decrease in kp0 (1.2 × 10−15 to 8.5 × 10−15 m2/(Pa s)). The frequency-dependence of dynamic compressive stiffness amplitude and phase, as well as the strain-dependence of permeability, were typical of the time- and strain-dependent mechanical behavior of articular cartilage. HA0 and Eten were positively correlated with the final PEG concentration, accounting for swelling. These results indicate that PEG hydrogels can be prepared to mimic many of the static and dynamic mechanical properties of articular cartilage.

Reinforcement of hydrogels using three-dimensionally printed microfibres

“…This is based on the principle that cells in native tissues are responsive to different types of mechanical stresses, such as compression, tension and shear [10][11][12] . These properties, for example stiffness, can be improved by increasing the hydrogel polymer concentration or crosslink density 2,3,13 or by the formation of tissue-specific extracellular matrix before implantation of the graft 2,14,15 . However, this generally compromises the biological performance of the hydrogel 2,3 or requires a long and costly period of pre-culture.…”

A Three-Dimensional Chondrocyte-Macrophage Coculture System to Probe Inflammation in Experimental Osteoarthritis

“…Poly(ethylene glycol) diacrylate (PEGDA)-based hydrogels were used in this study for the establishment of the 3D coculture system, due to their widespread use in cartilage tissue engineering, [34][35][36][37] their easily tunable mechanical properties, 38,39 and their ability to significantly resist cell adhesion even in serum-containing culture environments relative to many biomaterials. 34,40,41 This latter property permits desired cell adhesion to be ''programmed'' into the PEGDA network through conjugation of bioactive moieties.…”

Photopatternable PEDOT:PSS/PEG hybrid thin film with moisture stability and sensitivity

“…We had taken the specimens out of the DI water and dried them before the conductance measurement, in which the hybrid film swells and shrinks repeatedly due to moisture absorption. As reported, PEG hydrogels have a lower fracture strain than PDMS 43 ; thus, cracks and structure failure would occur at the PEDOT:PSS/PEG interface, especially when the hybrid film is under external mechanical forces. Due to hydrophobic nature of the PDMS substrate, interfacial strain between the PEG and PEDOT:PSS layers would increase gradually with the thickness of the PEG layer 44 .…”