Covalent Immobilization Of Collagen Research Articles

Enhanced Tissue Compatibility of Polyetheretherketone Disks by Dopamine-Mediated Protein Immobilization

Polyetheretherketone (PEEK) disks with hydrophilic and bioactive surface properties were prepared by covalent immobilization of collagen (Col) or insulin (In) on poly-dopamine (D)-coated PEEK samples using WSC (water soluble carbodiimide) as an activating agent. The poly-dopamine on the PEEK disk was coated by carrying out self-assembled polymerization of the dopamine neurotransmitter in a basic medium at pH 8.5. The poly-dopamine coating of the PEEK surface facilitated the deposition of a uniform layer of aligned molecules of collagen, which increased the bioactivity of the PEEK surfaces allowing for adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells in a minimum essential medium in the presence of 5% CO2 at 37 °C. The collagen-modified PEEK surface had higher bioactivity for MC3T3-E1 cells, compared to the self-assembled poly-dopamine coated PEEK surface or pristine PEEK alone. Alkaline phosphatase, von Kossa, and Alizarin red staining of MC3T3-E1 cells cultured on a collagen-modified PEEK surface, were all found to be increased compared to staining of cells cultured on other PEEK surfaces. The self-assembled polymerization of dopamine on a PEEK surface was found to be useful for the immobilization of proteins such as collagen and insulin. Thus, collagen-and insulinimmobilized PEEK provide an opportunity to enhance the bioactivity of the PEEK samples allowing for better cells adhesion and tissue integration for potential use in tissue implants.

Cytocompatible polyurethanes from fatty acids through covalent immobilization of collagen

Two different polyurethanes synthesized from two triols derived from undecenoic acid (PU1) and oleic acid (PU2) fatty acids were functionalised with Collagen type I via plasma treatment aimed at obtaining novel biomaterials with improved biological properties. Scanning Electron Microscopy, X-ray photoelectron spectroscopy, optical microscopy, colorimetric titration methods and contact angle measurements confirmed the surface changes at each stage of treatment, both in terms of morphology and chemical composition. The results for osteoblastic cells (MG63) cultured in vitro proved that PUs modified with collagen had better cytocompatibility that the control PUs. In particular, PU2 displays higher cytocompatibility.

Surface engineering of PHBV by covalent collagen immobilization to improve cell compatibility

Covalent immobilization of collagen onto poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film was achieved to improve its cell compatibility. Amide groups photografted on PHBV films were initially converted into amine groups through Hofmann degradation and collagen was then chemically bonded to amine groups, consequently forming the amide, amine, and collagen-modified PHBV. The structures of these modified PHBV films were confirmed by ATR-FTIR, XPS, and SEM analyses. Compared with that of PHBV film, surface wettability of the modified PHBV films enhanced remarkably. In particular, water contact angle of the collagen-modified PHBV film decreased from 65.0 degrees to 2.1 degrees within 130 s. Sheep chondrocytes cultured on PHBV and modified PHBV films were evaluated by cell adhesion test, MTT assay, and morphological observation under SEM. Results showed that the collagen-modified PHBV film had better cell adhesion and proliferation than other modified PHBV films and PHBV film. Chondrocytes on the collagen-modified PHBV film adhered through filopodia, spread by cytoplasmic webbing, and formed cells layer earlier than other modified ones, indicating that the collagen-modified PHBV is a promising biomaterial for cartilage tissue engineering.

Stable immobilization of rat hepatocytes as hemispheroids onto collagen‐conjugated poly‐dimethylsiloxane (PDMS) surfaces: Importance of direct oxygenation through PDMS for both formation and function

The highly oxygen-permeable material, poly-dimethylsiloxane (PDMS), has the potential to be applied to cell culture microdevices, but cell detachment from PDMS has been a major problem. In this study, we demonstrate that a combination of collagen covalently immobilized PDMS and an adequate oxygen supply enables the establishment of a stable, attached spheroid (hemispheroid) culture of rat hepatocytes. The bottom PDMS surfaces were first treated with oxygen plasma, then coupled with aminosilane followed by a photoreactive crosslinker, and they were finally reacted with a collagen solution. X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that the covalent immobilization of collagen on the surface occurred only where the crosslinker had been introduced. On the collagen-conjugated PDMS surface, rat hepatocytes organized themselves into hemispheroids and maintained the viability and a remarkably high albumin production at least for 2 weeks of culture. In contrast, hepatocytes on the other types of PDMS surfaces formed suspended spheroids that had low albumin production. In addition, we showed that blocking the oxygen supply through the bottom PDMS surface inhibited the formation of hemispheroids and the augmentation of hepatocellular function. These results show that appropriate surface modification of PDMS is a promising approach towards the development of liver tissue microdevices.

Improving cell adhesion on titanium by covalent immobilization of collagen

Improving cell adhesion on titanium by covalent immobilization of collagen

Soft tissue reaction to collagen-immobilized porous polyethylene: subcutaneous implantation in rats for 20 wk

Collagen-immobilized porous polyethylene, in which the immobilization was through covalent bonding, and virgin porous polyethylene were implanted subcutaneously in rats from 1 to 20 wk. The results were the ingrowth of the connective tissue into collagen-immobilized porous polyethylene was rich and contained a low level of inflammatory cellular infiltration compared with that of virgin porous polyethylene. The material-tissue interface showed that the living body-originated collagen fibres were firmly anchored into the immobilized collagen layer. These results suggested that covalent immobilization of collagen on to the biomaterial surface is useful in promoting the ingrowth of soft tissue and the tissue adhesion.

Tissue reactions induced by modified poly(vinyl alcohol) hydrogels in rabbit cornea.

The purpose of this study was to compare the tissue reactions induced by modified poly(vinyl alcohol) (PVA) hydrogels with other materials implanted in the rabbit cornea. PVA hydrogels with and without covalently bonded collagen were compared to ethylene-vinyl alcohol copolymer, and polysulfone discs. These materials were implanted in the rabbit corneal stroma. The resultant tissue reactions were histologically and clinically studied. The PVA hydrogels had high flux rates of glucose and L-lactic acid in vitro. Covalent immobilization of collagen onto their surface was found to render them more biocompatible. However, excessive ulceration and vascularization of the cornea still occurred in vivo, possibly because of extremely little blinking of the rabbits, which might cause desiccation of the cornea.