Response of osteoblasts on amine-based polymer coatings cor-relates with the amino group density
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ABSTRACT: The integration of implants can be improved by physical but mainly by chemical modifications of the implant surface. It has already been shown that amine-based coatings improve cell attachment, cell migration, and intracellular signaling. The aim of this study was to determine the role of the amino group density in this positive cell response by developing controlled amino-rich nano-layers. Using Clariom S microarrays to perform genome-wide expression profilng, changes in adhesion related genes after cultivation of osteoblast-like cells on an amino group-rich coating could be seen.
Project description:Background: Due to their excellent mechanical and biocompatibility properties, titanium-based implants are successfully used as biomedical devices. However, when new bone formation fails for different reasons, impaired fracture healing will become a clinical problem and will affect the patient's quality of life. This study proposes to design a new bioactive surface of titanium implants with a synergetic PEG biopolymer-based composition for gradual delivery of growth factors (FGF2, VEGF, and BMP4) during bone healing. Methods: The optimal architecture of non-cytotoxic polymeric coatings deposited by dip coating under controlled parameters was assessed both in cultured cells and on rat in vivo animal model (100% viability). Results: Notably, the titanium adsorbed polymer matrix induced an improved healing process when compared with the individual action of each biomolecules. High-performance mass spectrometry analysis demonstrated that recovery after a traumatic event is governed by specific differentially regulated proteins, acting in a coordinated response to the external stimulus. Predicted protein interactions shown by STRING analysis were well organized in hub-based networks related with response to chemical, wound healing and response to stress pathways. Conclusions: The described functional polymer coatings of the titanium implants demonstrated the significant improvement of bone healing process after injury.
Project description:Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physicochemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within 1 h following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating, and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology, and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna. Four replicates each of five toxicant exposure groups of ~20 animals and four replicates of control, unexposed animals. Each control was compared to each exposed data set for a total of 16 comparisons per chemical condition.
Project description:Capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) has become a valuable analytical technique in top-down proteomics (TDP) in recent years. CZE-MS/MS-based TDP typically employs separation capillaries with neutral coatings (i.e., linear polyacrylamide, LPA). However, issues related to separation resolution and reproducibility remain with the LPA-coated capillaries due to the unavoidable non-specific protein adsorption onto the capillary wall. Cationic coatings can be critical alternatives to LPA coating for CZE-MS/MS-based TDP due to the electrostatic repulsion between the positively charged capillary inner wall and proteoform molecules in the acidic separation buffer. Unfortunately, there are only very few studies using cationic coating-based CZE-MS/MS for TDP studies. In this work, we aimed to develop a simple and efficient approach for preparing separation capillaries with cationic coating, i.e., poly(acrylamide-co-(3-acrylamidopropyl)trimethylammonium chloride, PAMAPTAC for CZE-MS/MS-based TDP. The PAMAPTAC coating-based CZE-MS produced significantly better separation resolution of proteoforms compared to traditionally used LPA-coated approach. It achieved reproducible separation and measurement of simple proteoform mixture and a complex proteome sample (i.e., a yeast cell lysate) regarding migration time, proteoform intensity, and the number of proteoform identifications. The PAMAPTAC coating-based CZE-MS enabled the detection of large proteoforms (≥30 kDa) from the yeast cell lysate reproducibly without any size-based prefractionation. Interestingly, the electrophoretic mobility of proteoforms using the PAMAPTAC coating can be predicted accurately using a simple semiempirical model. The results render the PAMAPTAC coating as a valuable alternative to the LPA coating to advance CZE-MS-based TDP towards high-resolution separation and highly reproducible measurement of proteoforms in complex samples.
Project description:The purpose of the present study is to influence of CA coating on immortalized Schwann cells in vitro in comparison to standard culture conditions as well as to laminin as a positive standard. CA is a homopolymer of polysialic acid (PSA), which has â attached to the neuronal cell adhesion molecule (NCAM) â emerged as particulate attractive candidate for promoting morphological plasticity of axonal processes during axonal path finding and activity-dependent remodelling. For this purpose self-spotted microarrays with 352 neurospecific genes were hybridized with mRNA from immortalized Schwann cells cultivated on different coating conditions: In order to enable a comprehensive comparison to the established coating material laminin as well as to standard coating conditions (cultivation on the cell culture surface) a loop-design has been chosen, which is based on the dye-swap design and facilitates a direct comparison of the different states. Results from 3 microarrays are summarized in this study. The samples originate from different coatings. Microarrays were hybridized in a loop design with one common reference using a dye swap approach.
Project description:The goal of this study is to compare the RNA expression profile of wild-type C. elegans nematodes to mutants defective in the synthesis of the biogenic amine neurotransmitters dopamine, serotonin, tyramine, and octopamine in day 2 adults.
Project description:Our study shows reduced expression of Trace-Amine Associated Receptors (TAARs) in the olfactory epithelium of mice in which Taar elements 1 and 2 (TE1+2) are deleted in cis.
Project description:Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physicochemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within 1 h following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating, and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology, and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna.
Project description:The poor osseointegration of dental implants in diabetic patients has become a long-standing clinical problem. Magnesium has been proved to promote bone healing under normal conditions. Here, we elucidate the mechanism by which Mg2+ promotes vascularized osseointegration in diabetic status. We generated a diabetic mice model and demonstrated the alveolar bone healing was compromised, with significantly decreased angiogenesis. We then developed Mg-coating implants with hydrothermal synthesis. These implants sucessfully improved the vascularization and osseointegration in diabetic status. Mechanically, Mg2+ promoted the degradation of Kelch-like ECH associated protein 1 (Keap1) and the nucleation of nuclear factor erythroid 2-related factor 2 (Nrf2) by up-regulating the expression of sestrin 2 (SESN2) in endothelial cells, thus reducing the elevated levels of oxidative stress in mitochondria and relieving endothelial cell dysfunction under hyperglycemia. Altogether, our data proved that Mg2+ promoted vascularized osseointegration in diabetic mice by regulating endothelial mitochondrial metabolism.