Effect of poly(ethylene glycol) molecular weight on tensile and swelling properties of oligo(poly(ethylene glycol) fumarate) hydrogels for cartilage tissue engineering

Abstract

This study was designed to determine the effect of changes in poly(ethylene glycol) (PEG) molecular weight on swelling and mechanical properties of hydrogels made from a novel polymer, oligo(poly(ethylene glycol) fumarate) (OPF), recently developed in our laboratory. Properties of hydrogels made from OPF with initial PEG molecular weights of 860, 3900, and 9300 were examined. The PEG 3900 formulation had a tensile modulus of 23.1 +/- 12.4 kPa and percent elongation at fracture of 53.2 +/- 13.7%; the PEG 9300 formulation had similar tensile properties (modulus: 16.5 +/- 4.6 kPa, elongation: 76.0 +/- 26.4%). However, the PEG 860 gels had a significantly higher modulus (89.5 +/- 50.7 kPa) and a significantly smaller percent elongation at fracture (30.1 +/- 6.4%), when compared with other formulations. Additionally, there were significant differences in percent swelling between each of the formulations. Molecular weight between crosslinks (M(c)) and mesh size were calculated for each OPF formulation. M(c) increased from 2010 +/- 116 g/mol with PEG 860 to 6250 +/- 280 g/mol with PEG 9300. Mesh size calculations showed a similar trend (76 +/- 2 A for PEG 860 to 160 +/- 6 A for PEG 9300). It was also found that these hydrogels could be laminated if a second layer was added before the first had completely crosslinked. Mechanical testing of these laminated gels revealed that the presence of an interfacial area did not significantly alter their tensile properties. These results suggest that the material properties of OPF-based hydrogels can be altered by changing the molecular weight of PEG used in synthesis and that multilayered OPF hydrogel constructs can be produced, with each layer having distinct mechanical properties.

Differentiation of mesenchymal stem cells in heparin-containing hydrogels via coculture with osteoblasts

“…However, these materials were chosen because previous research has shown similar materials to have the appropriate mesh size (Å to nm) to allow diffusion of nutrients for cell encapsulation (Henke et al 2010;Temenoff et al 2002), while preventing potential confounding factors for this study, such as cell spreading. The high viability and number of cells (Fig.…”

Biosynthetic hydrogel scaffolds made from fibrinogen and polyethylene glycol for 3D cell cultures

“…1). Hydrogels made of PEG are ideally suited for this task because they are highly biocompatible [8] and exhibit versatile physical characteristics based on their weight percent, molecular chain length, and crosslinking density [9]. An additional advantage of PEG hydrogels is their ability to undergo a controlled liquid-to-solid transition (gelation) in the presence of a cell suspension [10].…”

Introduction to cell–hydrogel mechanosensing

“…These types of hydrogel are particularly useful in examining cellular behaviour owing to their biocompatibility, biodegradability and biofunctionality [68]. cornea agarose-fibrin [29] alginate-gelatin nanofibre [163] collagen [146,149,150] collagen-PLGLA nanofibre [160] alginate [34] cellulose [35] heparin [36] alginate-hyaluronic acid [33] collagen [190] collagen-chitosan [32] dextran [30,31] hyaluronic acid [44] alginate [27] collagen [23,24] dextran [25] gelatin [26] collagen [17,97] fibrin [37] agarose [51,175,179,196] alginate [126] chitosan [20,50] fibrin [42,51] gellan gum [22,51] hyaluronic acid [110] PEG [60] A key factor when examining cell-material mechano-interactions is the mechanisms of cell adhesion to the hydrogel. Cell surface receptors such as integrins bind to ligands within the hydrogel if such adhesion sites exist.…”

“…This leads to a less stable and less organized structure than that found in collagen. The most extensively examined synthetic hydrogel material is poly(ethylene glycol) and its derivatives (figure 2) that can be chemically modified by attaching other polymer groups thus allowing a wide range of physical characteristics that can affect how the hydrogel interacts with cells [60][61][62][63].…”