Elastic Membrane That Undergoes Mechanical Deformation Enhances Osteoblast Cellular Attachment and Proliferation

The main objective of this paper was to investigate the effect of transmission of force on bone cells that were attached to a deformable membrane. We functionalized a silastic membrane that measured 0.005 inches thickness and coated it with an extra cellular matrix (ECM) protein, fibronectin (FN). MC3T3-E1 osteoblast-like cells were cultured on the functionalized FN-coated membrane after which cell attachment and proliferation were evaluated. We observed an immediate attachment and proliferation of the bone cells on the functionalized membrane coated with FN, after 24 hours. Upon application of a mechanical force to cells cultured on the functionalized silicone membrane in the form of a dynamic equibiaxial strain, 2% magnitude; at 1-Hz frequency for 2 h, the osteoblast cells elicited slightly elevated phalloidin fluorescence, suggesting that there was reorganization of the cytoskeleton. We concluded from this preliminary data obtained that the engineered surface transduced applied mechanical forces directly to the adherent osteoblast cells via integrin binding tripeptide receptors, present in the FN molecules, resulting in the enhanced cellular attachment and proliferation

Exercise Reduces DNA Damage, Inflammation and Apoptotic Markers in the Brain of High Fat Fed Animals

Please view abstract in the attached PDF fil

Exercise Reduces High-Fat Diet Induced Colon Inflammation but Does Not Influence MUC2 Expression

Please see the pdf version of the abstract

Fibronectin adsorption on surface-activated poly(dimethylsiloxane) and its effect on cellular function

This article reports that surface modification of poly(dimethylsiloxane) (PDMS) influences fibronectin (Fn) adsorption and enhances cell attachment. Controlled adsorption of Fn on chemically activated polymer substrates is known to influence cellular function. Thin films of PDMS were spun cast on silicon wafers to obtain homogeneous and molecularly smooth surfaces. The films were made hydrophilic by exposure to ultraviolet ozone activation (PDMS*). The films then were characterized by contact angle goniometry, ellipsometry, atomic force microscopy (AFM). Rutherford backscattering spectrometry and X-ray photoelectron spectroscopy. Contact angle measurements indicated higher hydrophobicity of the nonactivated PDMS substrates than PDMS*. AFM scans of the substrates indicated higher surface roughness of PDMS* (Ra = 0.55 nm) than PDMS (Ra = 0.25 nm). Although Fn surface density (Γ) was slightly higher on PDMS than on PDMS*, due to hydrophobic interactions between substrate and Fn, cell function was greatly enhanced on the Fn-coated PDMS* (PDMS*-Fn) than on PDMS (PDMS-Fn). Higher attachment of MC3T3-E1 osteoblast-like cells was observed on PDMS*-Fn than on PDMS-Fn. Moreover, cell spreading and cytoskeleton organization after 72 h was clearly favored on the Fn-coated PDMS* surfaces. © 2004 Wiley Periodicals, Inc

Initial attachment of osteoblast-like cells on functionalized surfaces coated with calcium phosphate

Tissue engineering techniques which combine synthetic grafts with molecules and cells are considered as viable long term solutions for bone tissue repair and reconstruction procedures. The self SAM technology enables modeling of surface functional groups on biomaterials, while the concept of ion-selective precipitation reaction causes formation of Ca-P coating on these functionalized surfaces. Hydrophilic surfaces such as -COOH or -OH end groups have very powerful induction capability for the heterogeneous nucleation of hydroxyapatite-like layer, while nucleation could be prohibited on an - NH 2-terminated surface. Using the SAM technique we grafted three different organosilanes onto silicon wafers to yield -NH2, -COOH and -OH functionalized surfaces respectively. The surfaces were characterized by contact angle measurements, ellipsometry, FTIR, SEM/EDX and RBS. Ca-P coating was formed on the SAMs by immersion in a simulated physiological fluid (pH 7.4, at 37°C). FTIR showed dependence of the morphology of the Ca-P coating on both the type of surface functionality and on the duration of coating. The spectrum exhibited P-O and C-O absorption bands characteristic of a carbonated calcium hydroxyapatite with stronger P-O bands on -OH surface. MC3T3-E1 osteoblast-like cells were used in bioassays to study the effect of the end groups on the initial cellular attachment and alkaline phosphatase expression on Ca-P coated surfaces. Cell assays showed increased cellular attachment on the Ca-P coated-OH SAM, after cells were seeded for 1h, compared to the -NH 2 and -COOH-terminated surfaces, while up to 5x alkaline phosphatase activity was shown on Ca-P coated surfaces. At a low temperature therefore, the end groups of SAMs act as effective nucleation sites to induce formation of a biomimetic apatite coating, in a one-step biomineralization process. The most potent apatite forming surface, the -OH SAM surface, demonstrates that surface -OH groups are important to induce bone bioactive behavior at surfaces