Polydopamine-Based Interfacial Engineering of Extracellular Matrix Hydrogels for the Construction and Long-Term Maintenance of Living Three-Dimensional Tissues

Abstract

Diverse biological processes in the body rely on the ability of cells to exert contractile forces on their extracellular matrix (ECM). In three-dimensional (3D) cell culture, however, this intrinsic cellular property can cause unregulated contraction of ECM hydrogel scaffolds, leading to a loss of surface anchorage and the resultant structural failure of in vitro tissue constructs. Despite advances in the 3D culture technology, this issue remains a significant challenge in the development and long-term maintenance of physiological 3D in vitro models. Here, we present a simple yet highly effective and accessible solution to this problem. We leveraged a single-step surface functionalization technique based on polydopamine to drastically increase the strength of adhesion between hydrogel scaffolds and cell culture substrates. Our method is compatible with different types of ECM and polymeric surfaces and also permits prolonged shelf storage of functionalized culture substrates. The proof-of-principle of this technique was demonstrated by the stable long-term (1 month) 3D culture of human lung fibroblasts. Furthermore, we showed the robustness and advanced application of the method by constructing a dynamic cell stretching system and performing over 100 000 cycles of mechanical loading on 3D multicellular constructs for visualization and quantitative analysis of stretch-induced tissue alignment. Finally, we demonstrated the potential of our technique for the development of microphysiological in vitro models by establishing microfluidic 3D co-culture of vascular endothelial cells and fibroblasts to engineer self-assembled, perfusable 3D microvascular beds.

Surface-directed engineering of tissue anisotropy in microphysiological models of musculoskeletal tissue

“…Here, we have demonstrated, using SS chemistry as an example, that the surface anchorage method enables tethering of millimeter scale anisotropic tissues held in isometric tension during extended culture for up to 28 days without structural failure. Other methods of surface modification that enable scaffold anchorage can be used to similar effect ( 39 ).…”

Surface Modification Techniques for Endothelial Cell Seeding in PDMS Microfluidic Devices

“…PDA improves surface hydrophilicity by reducing WCA and introduces different functional groups for bioconjugation [ 84 ]. PDA-treated PDMS surface showed 50% decrease in WCA as compared to untreated PDMS [ 62 ]. A flow based surface modification technique by using PDA was utilized to design a microfluidic cell culture device for organ-on-a-chip study [ 63 ].…”

“…Similar modification was done by adding fibronectin instead of collagen-I [ 88 ]. PDA modified PDMS can drastically increase the adhesion of ECM scaffold and cell culture substrate [ 49 , 62 , 66 ]. A PDA functionalized PDMS device was constructed to maintain the long-term culture condition of vascular ECs and human lung fibroblasts co-culture in collagen-I [ 62 ].…”

“…PDA modified PDMS can drastically increase the adhesion of ECM scaffold and cell culture substrate [ 49 , 62 , 66 ]. A PDA functionalized PDMS device was constructed to maintain the long-term culture condition of vascular ECs and human lung fibroblasts co-culture in collagen-I [ 62 ]. PDA coated device provided a firm anchor for the hydrogel and maintained cell proliferation inside the gel for a month.…”

Lipopolysaccharide-Induced Vascular Inflammation Model on Microfluidic Chip

“…PDMS and cover glasses were sterilized by 70% ethanol, then assembled by plasma treatment. The assembled microfluidic devices were coated with 2.0 mg/mL polydopamine for enhanced adhesion of the hydrogel to the device ( Figure 1 ) [ 35 ]. After washing channels of microfluidic device with distilled water, the device was incubated in a 37 °C incubator for more than 12 h.…”