Biochemically and topographically engineered poly(ethylene glycol) diacrylate hydrogels with biomimetic characteristics as substrates for human corneal epithelial cells

Abstract

Incorporation of biophysical and biochemical cues into the design of biomaterials is an important strategy for tissue engineering, the design of biomedical implants and cell culture. Hydrogels synthesized from poly (ethylene glycol) diacrylate (PEGDA) were investigated as a platform to simultaneously present human corneal epithelial cells (HCECs) in vitro with topography and adhesion peptides to mimic the native physical and chemical attributes of the basement membrane underlying the epithelium in vivo. Hydrogels synthesized from aqueous solutions of 20% PEGDA (MW of 3400 g/mol) prevented non-specific cell adhesion and were functionalized with the integrin-binding peptide Arg-Gly-Asp (RGD) in concentrations from 5 to 20 mM. The hydrogels swelled minimally after curing and were molded with ridge and groove features with lateral dimensions from 200 nm to 2000 nm and 300 nm depth. HCECs were cultured on topographic surfaces functionalized with RGD and compared to control unfunctionalized topographic substrates. HCEC alignment, either parallel or perpendicular to ridges, was influenced by the culture media on substrates promoting non-specific attachment. In contrast, the alignment of HCECs cultured on RGD hydrogels showed substantially less dependence on the culture media. In the latter case, the moldable RGD-functionalized hydrogels allowed for decoupling the cues from surface chemistry, soluble factors, and topography that simultaneously impact HCEC behavior.

Arrays of topographically and peptide-functionalized hydrogels for analysis of biomimetic extracellular matrix properties

“…% PEGDA (MW 3400) retained the topographic features and had anti-fouling properties. 31 There was good fidelity between the stamp lateral dimensions and the resulting hydrated hydrogel surface dimensions; replica molded hydrogels had pitches of 400, 1400, or 4000 nm with groove depths ranging from 450 to approximately 200 nm, as measured with AFM (Fig. 2).…”

Wounding the cornea to learn how it heals

“…3D cultures are newer, more expensive, and more difficult to manipulate: much more research has been done using 2D cultures. Investigators have used corneal stromal cells derived from a variety of species for these types of studies (Dreier et al, 2013; Kim et al, 2010; Lakshman and Petroll, 2012; Micera et al, 2006; Yanez-Soto et al, 2013). …”

“…In 1994, one of the first 3D organotypic cell culture systems was described which incorporated the three major corneal cell types: endothelial cells, fibroblasts, and epithelial cells (Zieske et al, 1994). Building on those observations, 3D culture systems have been developed involving bioengineered scaffolds, to gain insight into collagen biosynthesis and scarring (Dreier et al, 2013; Karamichos et al, 2010; Ren et al, 2008; Ruberti and Zieske, 2008; Saeidi et al, 2012; Yanez-Soto et al, 2013). Other groups have used these types of models to study corneal stem cells (Papini et al, 2005).…”

The influence of substrate topography on the migration of corneal epithelial wound borders

“…Topographically-molded PEGDA hydrogels functionalized with the adhesive peptide RGD, a sequence found in wounded corneal epithelium BM [21], can provide human corneal epithelial cells (HCECs) with specific biomimetic cues inspired by the BM [22]. Here, we report the use of topographically and biochemically controlled poly(ethylene glycol) diacrylate (PEGDA) hydrogel substrates as an artificial BM simulant to improve the wound healing and functionality of the corneal epithelium.…”