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Sensors (Basel, Switzerland) Jul 2022Rubber is one of the most used materials in the world; however, raw rubber shows a relatively very low mechanical strength. Therefore, it needs to be cured before its...
Rubber is one of the most used materials in the world; however, raw rubber shows a relatively very low mechanical strength. Therefore, it needs to be cured before its ultimate applicatios. Curing process specifications, such as the curing time and temperature, influence the material properties of the final cured product. The transient radar method (TRM) is introduced as an alternative for vulcanization monitoring in this study. Three polyurethane-rubber samples with different curing times of 2, 4, and 5.5 min were studied by TRM to investigate the feasibility and robustness of the TRM in curing time monitoring. Additionally, the mechanical stiffness of the samples was investigated by using a unidirectional tensile test to investigate the potential correlations between curing time, dielectric permittivity, and stiffness. According to the results, the complex permittivity and stiffness of the samples with 2, 4, and 5.5 min of curing time was 17.33 ± 0.07 - (2.41 ± 0.04)j; 17.09 ± 0.05 - (4.90 ± 0.03)j; 23.60 ± 0.05 - (14.06 ± 0.06)j; and 0.29, 0.35, and 0.38 kPa, respectively. Further statistical analyses showed a correlation coefficient of 0.99 ( = 0.06), 0.80 ( = 0.40), and 0.92 ( = 0.25) between curing time-stiffness, curing time-permittivity (real part), and curing time-permittivity (imaginary part), respectively. The correlation coefficient between curing time and permittivity can show the potential of the TRM system in contact-free vulcanization monitoring, as the impact of vulcanization can be tracked by means of TRM.
Topics: Polyurethanes; Radar; Rubber; Temperature
PubMed: 35808504
DOI: 10.3390/s22135010 -
International Journal of Molecular... May 2023Fibrous membranes of thermoplastic polyurethane (TPU) were fabricated through a uni-axial electrospinning process. Fibers were then separately charged with two...
Fibrous membranes of thermoplastic polyurethane (TPU) were fabricated through a uni-axial electrospinning process. Fibers were then separately charged with two pharmacological agents, mesoglycan (MSG) and lactoferrin (LF), by supercritical CO impregnation. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis proved the formation of a micrometric structure with a homogeneous distribution of mesoglycan and lactoferrin. Besides, the degree of retention is calculated in four liquid media with different pHs. At the same time, angle contact analysis proved the formation of a hydrophobic membrane loaded with MSG and a hydrophilic LF-loaded one. The impregnation kinetics demonstrated a maximum loaded amount equal to 0.18 ± 0.20% and 0.07 ± 0.05% for MSG and LT, respectively. In vitro tests were performed using a Franz diffusion cell to simulate the contact with the human skin. The release of MSG reaches a plateau after about 28 h while LF release leveled off after 15 h. The in vitro compatibility of electrospun membranes has been evaluated on HaCaT and BJ cell lines, as human keratinocytes and fibroblasts, respectively. The reported data proved the potential application of fabricated membranes for wound healing.
Topics: Humans; Polyurethanes; Lactoferrin; Wound Healing; Skin; Nanofibers
PubMed: 37298221
DOI: 10.3390/ijms24119269 -
Molecules (Basel, Switzerland) May 2023In this study, poly(AA-co-ACMO) and polyurethane-based nanofibers were prepared in a ratio of 1:1 (NF11) and 2:1 (NF21) as antimicrobial carriers for chronic wound...
In this study, poly(AA-co-ACMO) and polyurethane-based nanofibers were prepared in a ratio of 1:1 (NF11) and 2:1 (NF21) as antimicrobial carriers for chronic wound management. Different techniques were used to characterize the nanofibers, and poly(AA-co-ACMO) was mostly found on the surface of PU. With an increase in poly(AA-co-ACMO) dose from 0 (PU) and 1:1 (NF11) to 2:1 (NF21) in the casting solution, the contact angle (CA) was reduced from 137 and 95 to 24, respectively, and hydrophilicity was significantly increased. As most medications inhibit biological processes by binding to a specific protein, in vitro protein binding was investigated mechanistically using a stopped-flow technique. Both NF11 and NF21 bind to BSA via two reversible steps: a fast second-order binding followed by a slow first-order one. The overall parameters for NF11 ( = 1.1 × 10 M, = 89.0 × 10, Δ = -23.1 kJ mol) and NF21 ( = 189.0 × 10 M, = 5.3 × 10 M, Δ = -27.5 kJ mol) were determined and showed that the affinity for BSA is approximately (NF11)/(NF21) = 1/180. This indicates that NF21 has much higher BSA affinity than NF11, although BSA interacts with NF11 much faster. NF21 with higher hydrophilicity showed effective antibacterial properties compared to NF11, in agreement with kinetic data. The study provided an approach to manage chronic wounds and treating protein-containing wastewater.
Topics: Polyurethanes; Nanofibers; Polymers; Anti-Bacterial Agents; Hydrophobic and Hydrophilic Interactions
PubMed: 37175361
DOI: 10.3390/molecules28093951 -
Medicina (Kaunas, Lithuania) Nov 2022: Curcumin (Cc) as an active substance is known for its anti-inflammatory, anticoagulant, antioxidant, and anti-carcinogenic effects, together with its role in...
: Curcumin (Cc) as an active substance is known for its anti-inflammatory, anticoagulant, antioxidant, and anti-carcinogenic effects, together with its role in cholesterol regulation, and its use in different gastrointestinal derangements. On the other hand, curcumin can be used for its properties as an inactive substance, with Cc particles being more often tested in pharmaceutical formulations for drug delivery, with promising safety records and kinetics. The aim of this research was to obtain and characterize polyurethane microparticles that can be used as a carrier with a controlled Cc release. : The in vitro samples were characterized by the Zetasizer procedure, and UV-Vis spectroscopy, while the in-vivo measurements on human subjects were performed by non-invasive skin assays (trans-epidermal water loss, erythema, and skin hydration). A total of 16 patients with oropharyngeal cancer stages II and III in equal proportions were recruited for participation. : The experimental values of sample characteristics using the Zetasizer identified a mean structural size of 215 nm in the polyester-urethane preparate (PU), compared to 271 nm in the curcumin-based PU. Although the size was statistically significantly different, the IPDI and Zeta potential did not differ significantly (22.91 mV vs. 23.74 mV). The average age during the study period was 57.6 years for patients in the PU group, respectively, and 55.1 years in those who received the curcumin preparations. The majority of oropharyngeal cancers were of HPV-related etiology. There were no significant side effects; 75.0% of patients in the PU group reporting no side effects, compared to 87.5% in the Cc group. The 48 h TEWL measurement at the end of the experiment found a statistically significant difference between the PU and the Cc group (2.2 g/h/m vs. 2.6 g/h/m). The erythema assessment showed a starting measurement point for both research groups with a 5.1-unit difference. After 48 h, the difference between PU and PU_Cc was just 1.7 units (-value = 0.576). The overall difference compared to the reference group with sodium lauryl sulfate (SLS) was statistically significant at a 95% significance level. : Our findings indicate the obtaining of almost homogeneous particles with a medium tendency to form agglomerations, with a good capacity of encapsulation (around 60%), a medium release rate, and a non-irritative potential. Therefore, this polyester-urethane with Cc microparticles can be tested in other clinical evaluations.
Topics: Humans; Middle Aged; Curcumin; Polyesters; Drug Delivery Systems; Polyurethanes; Oropharyngeal Neoplasms
PubMed: 36422227
DOI: 10.3390/medicina58111689 -
Journal of Materials Science. Materials... Aug 2021Electrospun polymers are an example of multi-functional biomaterials that improve the material-cellular interaction and aimed at enhancing wound healing. The main...
Electrospun polymers are an example of multi-functional biomaterials that improve the material-cellular interaction and aimed at enhancing wound healing. The main objective of this work is to fabricate electrospun polyurethane membranes using arginine as chain extender (PUUR) in order to test the fibroblasts affinity and adhesion on the material and the polymer toxicity. Polyurethane membranes were prepared in two steps: (i) the polyurethane synthesis, and ii) the electrospinning process. The membranes were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. The evaluation of PUUR as a scaffolding biomaterial for growing and developing of cells on the material was realized by LIVE/DEAD staining. The results show that the fluorescent surface area of human fibroblasts (hFB), was greater in control dense membranes made from Tecoflex than in electrospun and dense PUUR. From SEM analysis, the electrospun membranes show relatively uniform attachment of cells with a well-spread shape, while Tecoflex dense membranes show a non-proliferating round shape, which is attributed to the fiber's structure in electrospun membranes. The cell morphology and the cell attachment assay results reveal the well spreading of hFB cells on the surface of electrospun PUUR membranes which indicates a good response related to cell adhesion.
Topics: Arginine; Biocompatible Materials; Calorimetry, Differential Scanning; Cell Adhesion; Cell Survival; Colorimetry; Electrochemistry; Fibroblasts; Humans; Membranes, Artificial; Microscopy, Electron, Scanning; Molecular Weight; Nanofibers; Polymers; Polyurethanes; Porosity; Spectroscopy, Fourier Transform Infrared; Temperature; Tensile Strength; Tissue Engineering; Tissue Scaffolds; Wound Healing
PubMed: 34417669
DOI: 10.1007/s10856-021-06581-z -
Advanced Science (Weinheim,... Nov 2021The stress-response strategy is one of the nature's greatest developments, enabling animals and plants to respond quickly to environmental stimuli. One example is the...
The stress-response strategy is one of the nature's greatest developments, enabling animals and plants to respond quickly to environmental stimuli. One example is the stress-response strategy of the Venus flytrap, which enables such a delicate plant to perceive and prey on insects at an imperceptible speed by their soft terminal lobes. Here, inspired by this unique stress-response strategy, a soft gripper that aims at the challenges of high-speed dynamic grasping tasks is presented. The gripper, called high-speed soft gripper (HSG), is based on two basic design concepts. One is a snap-through instability that enables the HSG to sense the mechanical stimuli and actuating instantly. The other one is the spider-inspired pneumatic-powered control system that makes the trigger process repeatable and controllable. Utilizing the stress-response strategy, the HSG can accomplish high-speed sensing and grasping and handle a dynamic grasping task like catching a thrown baseball. Whereas soft machines typically exhibit slow locomotion speed and low manipulation strength for the intrinsic limitations of soft materials, the exploration of the stress-response strategy in this study can help pave the way for designing a new generation of practical high-speed soft robots.
Topics: Biological Phenomena; Equipment Design; Polyurethanes; Robotics; Tensile Strength
PubMed: 34473423
DOI: 10.1002/advs.202102539 -
Tissue Engineering. Part A Mar 2016Polyurethanes are versatile elastomers but suffer from biological limitations such as poor control over cell attachment and the associated disadvantages of increased...
Polyurethanes are versatile elastomers but suffer from biological limitations such as poor control over cell attachment and the associated disadvantages of increased fibrosis. We address this problem by presenting a novel strategy that retains elasticity while modulating biological performance. We describe a new biomaterial that comprises a blend of synthetic and natural elastomers: the biostable polyurethane Elast-Eon and the recombinant human tropoelastin protein. We demonstrate that the hybrid constructs yield a class of coblended elastomers with unique physical properties. Hybrid constructs displayed higher elasticity and linear stress-strain responses over more than threefold strain. The hybrid materials showed increased overall porosity and swelling in comparison to polyurethane alone, facilitating enhanced cellular interactions. In vitro, human dermal fibroblasts showed enhanced proliferation, while in vivo, following subcutaneous implantation in mice, hybrid scaffolds displayed a reduced fibrotic response and tunable degradation rate. To our knowledge, this is the first example of a blend of synthetic and natural elastomers and is a promising approach for generating tailored bioactive scaffolds for tissue repair.
Topics: Animals; Biocompatible Materials; Cell Proliferation; Elasticity; Elastomers; Humans; Implants, Experimental; Male; Mice, Inbred C57BL; Polyurethanes; Porosity; Prosthesis Implantation; Rheology; Stress, Mechanical; Subcutaneous Tissue; Tissue Engineering; Tissue Scaffolds; Tropoelastin
PubMed: 26857114
DOI: 10.1089/ten.TEA.2015.0409 -
Journal of Biomedical Materials... Nov 2021Congenital heart defects (CHDs) are the leading cause of death in live-born infants. Currently, patches used in the repair of CHDs are exclusively inert and...
Congenital heart defects (CHDs) are the leading cause of death in live-born infants. Currently, patches used in the repair of CHDs are exclusively inert and non-degradable, which increases the risk of arrhythmia, follow-up surgeries, and sudden cardiac death. In this preliminary study, we sought to fabricate biodegradable scaffolds that can support cardiac regeneration in the repair of CHDs. We electrospun biodegradable scaffolds using various blends of polyurethane (PU) and polycaprolactone (PCL) with and without sacrificial poly(ethylene oxide) (PEO) particles and assessed the mechanical properties, cell infiltration levels, and inflammatory response in vitro (surface cell seeding) and in vivo (subcutaneous mouse implant). We hypothesized that a blend of the two polymers would preserve the low stiffness of PU as well as the high cell infiltration observed in PCL scaffolds. The inclusion of PU in the blends, even as low as 10%, decreased cell infiltration both in vitro and in vivo. The inclusion of sacrificial PEO increased pore sizes, reduced Young's moduli, and reduced the inflammatory response in all scaffold types. Collectively, we have concluded that a PCL patch electrospun with sacrificial PEO particles is the most promising scaffold for further assessment as in our heart defect model.
Topics: Animals; Cell Line; Humans; Materials Testing; Mice; Polyesters; Polyurethanes; Tissue Engineering; Tissue Scaffolds
PubMed: 33876870
DOI: 10.1002/jbm.a.37201 -
ACS Biomaterials Science & Engineering May 2020Biodegradable cardiac patch is desirable to possess mechanical properties mimicking native myocardium for heart infarction treatment. We fabricated a series of...
Biodegradable cardiac patch is desirable to possess mechanical properties mimicking native myocardium for heart infarction treatment. We fabricated a series of anisotropic and biodegradable polyurethane porous scaffolds via thermally induced phase separation (TIPS) and tailored their mechanical properties by using various polyurethanes with different soft segments and varying polymer concentrations. The uniaxial mechanical properties, suture retention strength, ball-burst strength, and biaxial mechanical properties of the anisotropic porous scaffolds were optimized to mechanically match native myocardium. The optimal anisotropic scaffold had a ball burst strength (20.7 ± 1.5 N) comparable to that of native porcine myocardium (20.4 ± 6.0 N) and showed anisotropic behavior close to biaxial stretching behavior of the native porcine myocardium. Furthermore, the optimized porous scaffold was combined with a porcine myocardium-derived hydrogel to form a biohybrid scaffold. The biohybrid scaffold showed morphologies similar to the decellularized porcine myocardial matrix. This combination did not affect the mechanical properties of the synthetic scaffold alone. After rat subcutaneous implantation, the biohybrid scaffolds showed minimal immune response and exhibited higher cell penetration than the polyurethane scaffold alone. This biohybrid scaffold with biomimetic mechanics and good tissue compatibility would have great potential to be applied as a biodegradable acellular cardiac patch for myocardial infarction treatment.
Topics: Animals; Hydrogels; Myocardium; Polyurethanes; Rats; Swine; Tissue Engineering; Tissue Scaffolds
PubMed: 33313394
DOI: 10.1021/acsbiomaterials.9b01860 -
Applied and Environmental Microbiology Sep 2016Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it...
UNLABELLED
Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU.
IMPORTANCE
Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling.
Topics: Biodegradation, Environmental; Fungi; Gas Chromatography-Mass Spectrometry; Paint; Polyesters; Polyurethanes; Soil Microbiology
PubMed: 27316963
DOI: 10.1128/AEM.01344-16