Abstract 29: Biodegradable Elastomeric Polyurethane Scaffolds Mechanically Matching With Native Heart Muscle

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Cancan Xu ◽  
Bryn Brazile ◽  
Kytai Nguyen ◽  
Jun Liao ◽  
Liping Tang ◽  
...  
Keyword(s):  
Heart Muscle ◽  
Soft Segment ◽  
Phosphate Buffer Solution ◽  
Film Surface ◽  
Hexamethylene Diisocyanate ◽  
Porous Scaffolds ◽  
Buffer Solution ◽  
Molecular Weights ◽  
Initial Modulus ◽  
Significant Difference

Introduction: Biodegradable cardiac patches need to be mechanically matching with native heart muscle, in order to provide appropriate mechanical support to rapidly restore heart functions and promote tissue remodeling for myocardial infarction (MI) management. Here, we utilized chemical molecular design to develop biodegradable elastomers with low initial modulus and then process them into porous scaffolds mechanically matching with native heart muscle. Methods and Results: We synthesized various amorphous copolymers including poly (δ-valerolactone-co-ε-caprolactone) (PVCL) and poly (ether ester) triblock copolymers with various molecular weights and poly(ethylene glycol) (PEG) molecular weights (PVCL-PEG-PVCL). The polyurethanes were then synthesized from PVCL or PVCL-PEG-PVCL as a soft segment, hexamethylene diisocyanate (HDI) as a hard segment and putrescine as a chain extender. The polyurethane products were presented as PU-PEGx-VCLy, where x and y refer to molecular weights of PEG and PVCL, respectively. Five polymers including PU-VCL 2k , PU-VCL 6K , PU-PEG 1K -VCL 1K , PU-PEG 1K -VCL 6K and PU-PEG 2K -VCL 6K were obtained. All polymers gradually degraded in phosphate buffer solution and enzyme solution. The 3T3 fibroblasts can grow and proliferate on all polymer film surface within 5 day culture, indicating the polymers have good cellular compatibility. PU-VCL 6K , PU-PEG 1K -VCL 6K and PU-PEG 2K -VCL 6K were further processed into porous scaffolds using thermally induced phase separation (TIPS). The PU-PEG 2K -VCL 6K scaffold at wet state had 0.19 ± 0.08 MPa initial modulus, which has no significant difference from initial modulus (0.19 ± 0.04 MPa) of the native porcine heart muscle. But the tensile strength of this scaffold is lower than that of heart muscle, which requies to be improved in the future. Conclusions: A new family of biodegradable elastic polyurethanes was synthesized and processed into porous scaffolds. The scaffolds showed promising mechanical match with heart muscle. These biodegradable polyurethane scaffolds would find opportunities to be used as a cardiac patch for heart infarction treatment.

scholarly journals Synthesis, Characterization, and Biodegradation Studies of Poly(1,4-cyclohexanedimethylene-adipate-carbonate)s

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Ajay S. Chandure ◽  
Ganesh S. Bhusari ◽  
Suresh S. Umare
Keyword(s):  
Weight Loss ◽  
Enzymatic Degradation ◽  
Hydrolytic Degradation ◽  
Phosphate Buffer Solution ◽  
Film Surface ◽  
Solution Viscosity ◽  
Buffer Solution ◽  
Sem Images ◽  
Titanium Butoxide ◽  
Soil Burial

Aliphatic/alicyclic poly(1,4-cyclohexanedimethylene-adipate-carbonate)s (PCACs) were synthesized by a transesterification from 1,4-cyclohexamethylendimethanol (1,4-CHDM), adipic acid (AA), diethyl carbonate (DEC), and titanium butoxide Ti(OBu)4 as a transesterification catalyst. The synthesized PCACs were characterized by the Fourier transform infrared (FTIR), X-ray diffraction analysis (XRD), solubility, solution viscosity, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) for their structural, physical, thermal, and morphological investigation. The structure of synthesized PCACs was confirmed by FTIR. All TGA curves of PCACs shows 10% weight loss above 270°C, and they reveal good thermal stability. Biodegradability of PCACs was investigated by hydrolytic degradation at (pH 7.2 and 11.5), enzymatic degradation using Rhizopus delemar lips at 37°C in phosphate buffer solution (PBS), and soil burial degradation at 30°C. The hydrolytic degradation shows the greater rate of weight loss in PBS at pH-11.5 than pH-7.2. The hydrolytic and soil burial degradation shows faster rate of weight loss as compared to enzymatic degradation. Biodegradation rate of PCACs follows the order: PCAC-20 > PCAC-40 > PCAC-60. SEM images show that degradation occurred all over the film surface, creating holes and cracks. These biodegradable PCACs may be able to replace conventional polymer in the fabrication of packaging film in near future.

scholarly journals Transparent fluorinate acrylic polyurethane with hydrophobicity obtained by crosslinking of hydroxyl-containing fluoroacrylate copolymer with HDI trimer

2015 ◽  
Vol 33 (3) ◽  
pp. 451-459 ◽  
Author(s):  
Yudi Guo ◽  
Dongyan Tang ◽  
Fan Yang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Soft Segment ◽  
Monomer Concentration ◽  
Film Surface ◽  
Hexamethylene Diisocyanate ◽  
Crosslinking Degree ◽  
Fluorinated Polyurethane ◽  
Degradation Temperature ◽  
Acrylic Polyurethane ◽  
The Fourier Transform

Abstract Hydroxyl-containing fluoroacrylate copolymers with different fluorine and hydroxyl concentrations were synthesized via free-radical solution polymerization. Transparent fluorinated polyurethane (FPU) films were prepared by curing the copolymers with HDI (hexamethylene diisocyanate) trimer. The Fourier transform infrared spectroscopy (FT-IR) results revealed introduction of fluorine both into the copolymer and polyurethane. X-ray photoelectron spectroscopy (XPS) analyses indicated that a gradient concentration of fluorine existed in the depth profile of the fluorinated polyurethane films. The highest contact angle (CA) was obtained for the FPU film with fluoroacrylate monomer concentration of 22 wt.% because of fluorine present on the film surface. The surface topographies detected by SEM and AFM indicated that surface roughness contributed little to the film hydrophobicity. By increasing the fluoroacrylate monomer concentration, the decreasing of crosslinking degree of hard segment resulted in lowering the first degradation temperature, while more C-F groups in soft segment led to higher second degradation temperature. UV-Vis spectrophotometer measurements indicated that the FPU film with the fluoroacrylate monomer concentration of 16 wt.% still had a high transmittance of more than 90 % in the whole visible wavelength range.

A microfluidic device with integrated impedance detection for λ-DNA

2003 ◽  
Vol 773 ◽  
Author(s):  
Myung-Il Park ◽  
Jonging Hong ◽  
Dae Sung Yoon ◽  
Chong-Ook Park ◽  
Geunbae Im
Keyword(s):  
Microfluidic Device ◽  
Electrochemical Impedance ◽  
Direct Detection ◽  
Full Potential ◽  
Label Free ◽  
Buffer Solution ◽  
Detection Systems ◽  
Significant Difference ◽  
Detection Of Biomolecules ◽  
Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration

1985 ◽  
Vol 17 (10) ◽  
pp. 39-41 ◽  
Author(s):  
A. Schnattinger
Keyword(s):  
Membrane Filtration ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Phosphate Buffer Solution ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Two Stage

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus. Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers. The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2). A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV. HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates. The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

scholarly journals Electro-Polymerized Titan Yellow Modified Carbon Paste Electrode for the Analysis of Curcumin

Surfaces ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 191-204
Author(s):  
Edwin S. D’Souza ◽  
Jamballi G. Manjunatha ◽  
Chenthattil Raril ◽  
Girish Tigari ◽  
Huligerepura J. Arpitha ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Solution Ph ◽  
Real Sample Analysis ◽  
Titan Yellow ◽  
Paste Electrode

A modest, efficient, and sensitive chemically modified electrode was fabricated for sensing curcumin (CRC) through an electrochemically polymerized titan yellow (TY) modified carbon paste electrode (PTYMCPE) in phosphate buffer solution (pH 7.0). Cyclic voltammetry (CV) linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) approaches were used for CRC detection. PTYMCPE interaction with CRC suggests that the electrode exhibits admirable electrochemical response as compared to bare carbon paste electrode (BCPE). Under the optimized circumstances, a linear response of the electrode was observed for CRC in the concentration range 2 × 10−6 M to 10 × 10−6 M with a limit of detection (LOD) of 10.94 × 10−7 M. Moreover, the effort explains that the PTYMCPE electrode has a hopeful approach for the electrochemical resolution of biologically significant compounds. Additionally, the proposed electrode has demonstrated many advantages such as easy preparation, elevated sensitivity, stability, and enhanced catalytic activity, and can be successfully applied in real sample analysis.

Influence of Red Blood Cell Concentrations on the Measurement of Turbulence Using Hot-Film Anemometer

1983 ◽  
Vol 105 (4) ◽  
pp. 406-410 ◽  
Author(s):  
A. M. Sallam ◽  
N. H. C. Hwang
Keyword(s):  
Phosphate Buffer Solution ◽  
Experimental Information ◽  
Characteristic Change ◽  
Density Functions ◽  
Buffer Solution ◽  
Number Range ◽  
Flow Phenomenon ◽  
Human Red Blood Cells ◽  
Spectral Density Functions ◽  
Hot Film

Measurement of local velocity fluctuations was made with an L-shaped conical hot-film probe in a submerged circular jet. The experiment was carried out in solutions of washed human red blood cells (RBC) in a phosphate buffer solution (PBS), at hematocrit concentrations (Ht percent) of 10, 19, 29, and 38 percent. The viscosity of the testing solutions was kept at 3.2 c.p. by adding proper amount of dextran. The experiment was conducted at Reynolds numbers (NR) 674, 963, 1255 and 1410, based on the jet exit velocity and exit diameter. Statistical analyses were performed on the recorded instantaneous velocity signals to obtain the root-mean-square (rms) values, the probability density functions (PDF) and the power spectral density functions (PSDF) of the signals. Within the range tested, we noticed an incidental rise in rms values at 19 to 29 Ht percent for NR = 963 similar to those reported earlier in the literature. Further analyses using PDF and PSDF, however, showed neither a trend nor any physical significance of this rise. Based on the analyses of both the PDF and the PSDF, we believe that the incidental rise in rms value can be partially attributed to the high spikes registered by the probe in a high RBC concentrations fluid flow. The bombardment of RBC on the probe thermal boundary layer may cause a characteristic change in the probe response to certain flow phenomenon, at least within the Reynolds number range used in this study. Additional theoretical and experimental information is needed to pin point the nature of this response. We thus suggest that the second and higher moments of the HFA signals obtained in a fluctuating flow field involving a liquid with relatively high contaminant concentrations cannot be interpreted as a simple flow phenomenon.

Electrochemical Determination of Uric Acid at CdTe Quantum Dot Modified Glassy Carbon Electrodes

2015 ◽  
Vol 98 (5) ◽  
pp. 1260-1266 ◽  
Author(s):  
Deng Pan ◽  
Shengzhong Rong ◽  
Guangteng Zhang ◽  
Yannan Zhang ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Uric Acid ◽  
Quantum Dot ◽  
Glassy Carbon ◽  
Semiconductor Nanocrystals ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Buffer Solution ◽  
Peak Current ◽  
Cdte Quantum Dot

Abstract Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of uric acid (UA) at a CdTe quantum dot (QD) modified the glassy carbon electrode (GCE). CdTe QDs, as new semiconductor nanocrystals, can greatly improve the peak current of UA. The anodic peak current of UA was linear with its concentration between 1.0 × 10–6 and 4.0 × 10–4 M in 0.1 M pH 5.0 phosphate buffer solution. The LOD for UA at the CdTe electrode (1.0 × 10–7 M) was superior to that of the GCE. In addition, we also determined the effects of scan rate, pH, and interferences of UA for the voltammetric behavior and detection. The results indicated that modified electrode possessed excellent reproducibility and stability. Finally, a new and efficient electrochemical sensor for detecting UA was developed.

Bacterial chemotaxis to fungal propagules in vitro and in soil

1983 ◽  
Vol 29 (9) ◽  
pp. 1104-1109 ◽  
Author(s):  
D. K. Arora ◽  
A. B. Filonow ◽  
J. L. Lockwood
Keyword(s):  
Sandy Loam ◽  
Phosphate Buffer Solution ◽  
Bacterial Chemotaxis ◽  
Macrophomina Phaseolina ◽  
Buffer Solution ◽  
Erwinia Herbicola ◽  
Cochliobolus Victoriae ◽  
Fungal Propagules ◽  
Loam Soil

Erwinia herbicola, Pseudomonas fluorescens, and P. putida were strongly attracted in vitro to substances exuded by conidia of Cochliobolus victoriae and sclerotia of Macrophomina phaseolina, but not to phosphate buffer solution. Numbers of bacteria attracted to propagules of C. victoriae or M. phaseolina in an unsterilized sandy loam soil were significantly (P = 0.05) greater than background populations occurring in soil saturated with buffer. Chemotactic response was greater to C. victoriae than to M. phaseolina both in vitro and in soil. Results suggest that living fungal propagules may act as attractants for motile bacteria in soil.

Surface Morphological Changes Accompanying Dissolution of Bioactive Glass: Effect of Residual Stress

2008 ◽  
Vol 47-50 ◽  
pp. 1302-1306 ◽  
Author(s):  
John A. Nychka ◽  
Ding Li
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Bioactive Glass ◽  
Morphological Changes ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Mechanochemical Effect ◽  
Dissolution Behaviour ◽  
Glass Surfaces

We report our observations concerning the time evolution of surface morphology occurring during the in vitro immersion of bioactive glass surfaces in contact with phosphate buffer solution. We compare regions under intentionally produced residual stresses via micro-indentation to those where no indentation was performed. The sign of the residual stress is shown to be important for predicting dissolution behaviour; compression retards dissolution, whereas tension enhances dissolution. We analyze our results with a simple model for the work of bond dissociation. We report that a highly constrained residual compressive stress state, such as in an indent, leads to a work deficit in comparison to tension, which accounts for the slower dissolution rate of compressed bioactive glass. Such a mechanochemical effect suggests that the presence of residual stresses from the manufacture of biomedical implants and devices could lead to accelerated or delayed dissolution and that careful control of residual stresses should be sought for predictable performance in dissolvable materials.

Sign in / Sign up

Export Citation Format

Share Document