Biomedical subjects

Martin Kantlehner

Publications and source records attributed to Martin Kantlehner.

3 recordsLinked to original sources

PubMed2005

Titanium implant materials with improved biocompatibility through coating with phosphonate-anchored cyclic RGD peptides.

One key point for improving osseous integration of implants is to render them osteopromotive by specifically favoring the adhesion of osteoblasts. Mimicking the physiological adhesion process of osteoblasts to the extracellular matrix improves cell adhesion in vitro and results in improved and earlier osseous integration of implants in vivo. Our approach involves coating titanium implants with a tailor-made cyclic-RGD peptide, thus allowing them to bind to specific integrin receptors on the cell surface through multimeric phosphonates. The advantages of this very stable, new type of anchoring for practical application are presented.

Animals↗

PubMed2004

Activation of integrin function by nanopatterned adhesive interfaces.

To study the function behind the molecular arrangement of single integrins in cell adhesion, we designed a hexagonally close-packed rigid template of cell-adhesive gold nanodots coated with cyclic RGDfK peptide by using block-copolymer micelle nanolithography. The diameter of the adhesive dots is < 8 nm, which allows the binding of one integrin per dot. These dots are positioned with high precision at 28, 58, 73, and 85 nm spacing at interfaces. A separation of > or = 73 nm between the adhesive dots results in limited cell attachment and spreading, and dramatically reduces the formation of focal adhesion and actin stress fibers. We attribute these cellular responses to restricted integrin clustering rather than insufficient number of ligand molecules in the cell-matrix interface since "micro-nanopatterned" substrates consisting of alternating fields with dense and no nanodots do support cell adhesion. We propose that the range between 58-73 nm is a universal length scale for integrin clustering and activation, since these properties are shared by a variety of cultured cells.

Cell Adhesion↗

PubMed2002

RGD-peptides for tissue engineering of articular cartilage.

One keypoint in the development of a biohybrid implant for articular cartilage defects is the specific binding of cartilage cells to a supporting structure. Mimicking the physiological adhesion process of chondrocytes to the extracellular matrix is expected to improve cell adhesion of in vitro cultured chondrocytes. Our approach involves coating of synthetic scaffolds with tailor-made, cyclic RGD-peptides, which bind to specific integrin receptors on the cell surface. In this study we investigated the expression pattern of integrins on the cell surface of chondrocytes and their capability to specifically bind to RGD-peptide coated materials in the course of monolayer cultivation. Human chondrocytes expressed integrins during a cultivation period of 20 weeks. Receptors proved to be functionally active as human and pig chondrocytes attached to RGD-coated surfaces. A competition assay with soluble RGD-peptide revealed binding specificity to the RGD-entity. Chondrocyte morphology changed with increasing amounts of cyclic RGD-peptides on the surface.

Amino Acid Sequence↗