Collagen type-IV Langmuir and Langmuir–Schäfer layers as model biointerfaces to direct stem cell adhesion

Abstract

In biomaterial development, the design of material surfaces that mimic the extra-cellular matrix (ECM) in order to achieve favorable cellular instruction is rather challenging. Collagen-type IV (Col-IV), the major scaffolding component of Basement Membranes (BM), a specialized ECM with multiple biological functions, has the propensity to form networks by self-assembly and supports adhesion of cells such as endothelial cells or stem cells. The preparation of biomimetic Col-IV network-like layers to direct cell responses is difficult. We hypothesize that the morphology of the layer, and especially the density of the available adhesion sites, regulates the cellular adhesion to the layer. The Langmuir monolayer technique allows for preparation of thin layers with precisely controlled packing density at the air–water (A–W) interface. Transferring these layers onto cell culture substrates using the Langmuir–Schäfer (LS) technique should therefore provide a pathway for preparation of BM mimicking layers with controlled cell adherence properties. In situ characterization using ellipsometry and polarization modulation-infrared reflection absorption spectroscopy of Col-IV layer during compression at the A–W interface reveal that there is linear increase of surface molecule concentration with negligible orientational changes up to a surface pressure of 25 mN m−1. Smooth and homogeneous Col-IV network-like layers are successfully transferred by LS method at 15 mN m−1 onto poly(ethylene terephthalate) (PET), which is a common substrate for cell culture. In contrast, the organization of Col-IV on PET prepared by the traditionally employed solution deposition method results in rather inhomogeneous layers with the appearance of aggregates and multilayers. Progressive increase in the number of early adherent mesenchymal stem cells (MSCs) after 24 h by controlling the areal Col-IV density by LS transfer at 10, 15 and 20 mN m−1 on PET is shown. The LS method offers the possibility to control protein characteristics on biomaterial surfaces such as molecular density and thereby, modulate cell responses.

Laminin–Dynamic Bonds Enable Multifunctionality in a Biological 2D Network

“…For thin organic films, the ellipsometric angle Δ contains information about both film thickness and refractive index. [ 24 ] Recently, we have shown that for Col IV, Δ is proportional to the areal surface excess protein concentration, [ 25 ] and we hypothesize that this applies to Lam‐111 given its similar structure. As evident in Figure 3A, there was a fast increase in Δ after spreading and this Δ value plateaus after ≈40 min, indicating that the surface excess concentration was relatively constant after this period.…”

Ultrathin collagen type I films formed at the air-water interface

“…Δ was plotted against the reciprocal trough area A for different compression rates of 30, 50 and 70 mm/min (see SI Fig. S1) and the mass of adsorbed protein was determined according to a relationship established in our previous work [14]:…”

A Hyaluronan Hydrogel Scaffold for Culture of Human Oral Mucosal Epithelial Cells in Limbal Stem-Cell Therapy

“…It regulates cell adhesion, supports chemotaxis and migration, and directs tissue development [38]. Among the 29 collagen proteins identified, collagen IV is the major scaffolding component of basement membranes, where its self-assembled ropelike networks are formed to support adhesion of stem cells [39,40]. The adhesion mechanism is proposed to be through α1β1, α2β1, α10β1 and α11β1 integrins that are responsible for linking the ECM with the intracellular cytoskeleton [41,42].…”

“…The coating of substrates for cell culture is commonly performed by incubating a solution of collagen IV on the material for several hours to deposit a layer, followed by washing off the excess solution. Factors such as hydrophilicity of substrate and surface charge play important roles in formation of collagen IV layers by solution deposition method [39,48,49].…”