Biological nano-functionalization of titanium-based biomaterial surfaces: a flexible toolbox

Abstract

Surface functionalization with bioactive molecules (BAMs) on a nanometre scale is a main field in current biomaterial research. The immobilization of a vast number of substances and molecules, ranging from inorganic calcium phosphate phases up to peptides and proteins, has been investigated throughout recent decades. However, in vitro and in vivo results are heterogeneous. This may be at least partially attributed to the limits of the applied immobilization methods. Therefore, this paper highlights, in the first part, advantages and limits of the currently applied methods for the biological nano-functionalization of titanium-based biomaterial surfaces. The second part describes a new immobilization system recently developed in our groups. It uses the nanomechanical fixation of at least partially single-stranded nucleic acids (NAs) into an anodic titanium oxide layer as an immobilization principle and their hybridization ability for the functionalization of the surface with BAMs conjugated to the respective complementary NA strands.

Lysophosphatidic acid-functionalised titanium as a superior surface for supporting human osteoblast (MG63) maturation

“…Surface functionalisation of titanium with bioactive molecules is a key feature of contemporary biomaterials research, indeed a concerted global effort has ensued to enhance the performance and longevity of titanium through surface modifications that include both non-covalent and covalent functionalisation strategies (Beutner et al, 2010 and references therein). With regard to biological agents, Contact angles were measured using water with three measurements taken from the surface of each sample.…”

“…Closely associated with identifying suitable bioactives, are identifying appropriate strategies for attachment of selected molecules to the implant material, whilst, importantly, retaining their biological activity. Although non-covalent steps have been taken to bolster the performance of titanium (Beutner et al, 2010;Hanawa, 2011), it is our opinion that the suitability of such measures to enhance biomaterial functionality in high-performance environments, such as total joint arthroplasty, is unlikely to succeed. Our reasoning is largely pragmatic; selected molecules are more likely to remain tethered to the biomaterial surface and withstand the rigors of implantation if bonded covalently.…”

Multifunctional biomaterial coatings: synthetic challenges and biological activity

“…Another affinity-based approach is the already described strategy that employs the self-organization of nucleic acids. If differently modified complementary strands are used, a multifunctional coating can be easily obtained (Beutner et al, 2010;Zhang et al, 2013).…”

“…This immobilization strategy consists of the adsorption of single nucleic acids strands by their terminal phosphate, followed by fixation in an anodic oxide layer (Beutner et al, 2010). The incubation with complementary strands that carry a biomolecule consequentially functionalizes the titanium or gold surface (Michael et al, 2009;Schliephake et al, 2015).…”

Biological Functionalization of Dental Implants with Fibronectin : A Scanning Electron Microscopic Study

“…Furthermore, the biological functionalization of implant's surfaces, by adding biomimetic bioactive substances to improve its biological characteristics, has also been recently investigated. (5)(6)(7) Generally, the bone-to-implant interaction is complex and does not depend on surface topography only. Chemical or biochemical composition of implant surface also plays a key role in the early stages of bone formation.…”