title: The effect of polyethylene glycol on the stability of pores in polyvinyl alcohol hydrogels during annealing.
abstract: Poly(vinyl alcohol) (PVA) hydrogels are candidate biomaterials for cartilage resurfacing or interpositional arthroplasty devices requiring high-creep resistance and high water content to maintain lubricity. Annealing of PVA improves creep resistance but also reduces the water content. We hypothesized that maintaining poly(ethylene glycol) (PEG) within PVA during annealing would prevent the collapse of the pores and thus would result in high equilibrium water content (EWC). Our hypothesis tested positive. The PVA hydrogels containing PEG maintained their opacity through annealing and exhibited large pores under confocal imaging while hydrogels not containing PEG turned translucent and no pores were visible after annealing. The EWC of gels annealed with PEG (83 +/- 1.0%) was higher than that of the gels processed without PEG (55 +/- 4.8). The crystallinity of the former was 8.0 +/- 1.7% and the latter was 27.5 +/- 8.7%. The hydrogels processed in the presence of PEG exhibited a significantly higher total creep strain (69 +/- 3.4%) when compared to the PEG-free hydrogels (17 +/- 3.7) under an initial contact stress of 0.45 MPa. EWC appeared to be strongly related to the creep resistance of annealed PVA theta-gels.
authors.affiliation: Harris Orthopaedic Biomechanics and Biomaterials Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital, 55 Fruit Street, GRJ-1206, Boston, MA 02114, USA.
authors.forename: Hatice
authors.initials: H
authors.lastname: Bodugoz-Senturk
authors.forename: Jeeyoung
authors.initials: J
authors.lastname: Choi
authors.forename: Ebru
authors.initials: E
authors.lastname: Oral
authors.forename: Jean H
authors.initials: JH
authors.lastname: Kung
authors.forename: Celia E
authors.initials: CE
authors.lastname: Macias
authors.forename: Gavin
authors.initials: G
authors.lastname: Braithwaite
authors.forename: Orhun K
authors.initials: OK
authors.lastname: Muratoglu
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D018613:Microscopy, Confocal; D011092:Polyethylene Glycols / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D016062:Porosity; D014867:Water / Q000737:chemistry
chemical_list: C062364:polyvinyl alcohol hydrogel; D014867:Water; D011092:Polyethylene Glycols; D011142:Polyvinyl Alcohol