Usage of polymer brushes as substrates of bone cells

Fabrication and Impact of Fouling-Reducing Temperature-Responsive POEGMA Coatings with Embedded CaCO3 Nanoparticles on Different Cell Lines

In the present work, we have successfully prepared and characterized novel nanocomposite material exhibiting temperature-dependent surface wettability changes, based on grafted brush coatings of non-fouling poly(di(ethylene glycol)methyl ether methacrylate) (POEGMA) with the embedded CaCO3 nanoparticles. Grafted polymer brushes attached to the glass surface were prepared in a three-step process using atom transfer radical polymerization (ATRP). Subsequently, uniform CaCO3 nanoparticles (NPs) embedded in POEGMA-grafted brush coatings were synthesized using biomineralized precipitation from solutions of CaCl2 and Na2CO3. An impact of the low concentration of the embedded CaCO3 NPs on cell adhesion and growth depends strongly on the type of studied cell line: keratinocytes (HaCaT), melanoma (WM35) and osteoblastic (MC3T3-e1). Based on the temperature-responsive properties of grafted brush coatings and CaCO3 NPs acting as biologically active substrate, we hope that our research will lead to a new platform for tissue engineering with modified growth of the cells due to the release of biologically active substances from CaCO3 NPs and the ability to detach the cells in a controlled manner using temperature-induced changes of the brush.

Development of a Surface-Functionalized Titanium Implant for Promoting Osseointegration: Surface Characteristics, Hemocompatibility, and In Vivo Evaluation

This study aimed to evaluate the impact of surface-modified biomedical titanium (Ti) dental implant on osseointegration. The surfaces were modified using an innovative dip-coating technique (IDCT; sandblasted, large-grit, and acid-etched, then followed by coating with the modified pluronic F127 biodegradable polymer). The surface morphology and hemocompatibility evaluations were investigated by field-emission scanning electron microscopy, while the contact analysis was observed by goniometer. The IDCT-modified Ti implant was also implanted in patients with missing teeth by single-stage surgical procedure then observed immediately and again four months after placement by cone-beam computerized tomography (CBCT) imaging. It was found that the IDCT-modified Ti implant was rougher than the dental implant without surface modification. Contact angle analysis showed the IDCT-modified Ti implant was lower than the dental implant without surface modification. The hemocompatibility evaluations showed greater red blood cell aggregation and fibrin filament formation on the IDCT-modified Ti implant. The radiographic and CBCT image displayed new bone formation at four months after the IDCT-modified Ti implant placement. Therefore, this study suggests that the IDCT-modified Ti dental implant has great potential to accelerate osseointegration.

Anionic Polymer Brushes for Biomimetic Calcium Phosphate Mineralization-A Surface with Application Potential in Biomaterials

This article describes the synthesis of anionic polymer brushes and their mineralization with calcium phosphate. The brushes are based on poly(3-sulfopropyl methacrylate potassium salt) providing a highly charged polymer brush surface. Homogeneous brushes with reproducible thicknesses are obtained via surface-initiated atom transfer radical polymerization. Mineralization with doubly concentrated simulated body fluid yields polymer/inorganic hybrid films containing AB-Type carbonated hydroxyapatite (CHAP), a material resembling the inorganic component of bone. Moreover, growth experiments using Dictyostelium discoideum amoebae demonstrate that the mineral-free and the mineral-containing polymer brushes have a good biocompatibility suggesting their use as biocompatible surfaces in implantology or related fields.

Coatings from micropatterned sulfobetaine polymer brushes as substrates for MC3T3-E1 cells

In the last decades, polymer brush coatings have proven to be excellent anti-fouling materials by preventing protein adhesion. When using this property to restrict cell growth laterally in cell culture, it is crucial to ensure that other cell functions remain unaffected. The present study therefore examines MC3T3-E1 cell growth and morphology on patterned PSBMA brush substrates and probes their proliferation potential at mRNA level. The osteoblastic cells display a more elongated morphology than cells on the control substrates, but show no sign of elevated levels of the apoptosis marker p53 or diminished levels of Ki-67 or H4, which serve as indicators of proliferation. Therefore, patterned polymer brushes do not seem to influence cells in their proliferation state and are suitable cell culture substrates. Nevertheless, the use of polymer brush surfaces in long-term cell culture was found to be limited by their instability in cell culture medium.

Ordered and disordered proteins as nanomaterial building blocks

Proteins possess a number of attractive properties that have contributed to their recent emergence as nanoscale building blocks for biomaterials and bioinspired materials. For instance, the amino acid sequence of a protein can be precisely controlled and manipulated via recombinant DNA technology, and proteins can be biosynthesized with very high purity and virtually perfect monodispersity. Most importantly, protein-based biomaterials offer the possibility of technologically harnessing the vast array of functions that these biopolymers serve in nature. In this review, we discuss recent progress in the field of protein-based biomaterials, with an overall theme of relating protein structure to material properties. We begin by discussing materials based on proteins that have well-defined three-dimensional structures, focusing specifically on elastin- and silk-like peptides. We then explore the newer field of materials based on intrinsically disordered proteins, using nucleoporin and neurofilament proteins as case studies. A key theme throughout the review is that specific environmental stimuli can trigger protein conformational changes, which in turn can alter macroscopic material properties and function.