Search Results (38)

Polyurethane (PU) is widely employed in the biomedical field. As application scenarios become increasingly complex, it is essential to modify PU to meet diverse requirements. Additionally, the degradation of PU is closely linked to the sustainability of its function, with degradation products having a direct impact on adjacent tissues. In this study, a novel PU containing double bonds in its main chain was developed. We investigated the influence of various ratios of soft segment composition on the degradation performance of PU, maintaining a fixed ratio of soft to hard segments and utilizing specific synthesis methods. The structure and molecular weight of the PU were analyzed using FTIR, NMR, and GPC techniques. The results of physical and chemical performance tests indicated that an increase in polycaprolactone diol (PCL diol) content within the soft segment enhanced the mechanical properties, hydrophobicity, and degradation performance of the PU. A further assessment of the degradation toxicity of PU was carried out using zebrafish as a model organism. The findings indicated that the degradation solution of PU exhibited slight toxicity to zebrafish embryonic development over prolonged degradation periods. However, it also significantly enhanced the hatching of zebrafish embryos. In summary, the novel PU developed in this study demonstrates favorable biocompatibility, and the approach of introducing reaction sites or modifying the composition of its soft segments within the molecular structure offers a promising and effective strategy to address specific application requirements. Full article

Background: The volatile compounds present in rose extracts exhibit significant potential applications in medicine and cosmetics due to their capacity to enhance skin hydration and barrier function, two factors that are crucial for anti-aging and skin protection. The antimicrobial, anti-inflammatory, and analgesic properties of these extracts also suggest their potential utility in oral health applications. The aim of the current study was to obtain a new type of polyurethane delivery system based on a polyaddition process in the presence of a surfactant. Methods: Lysine-diisocyanate, polyethylene glycol, polycaprolactone diol, hexanediol, glycerol-1,2-diacetate, Tween^® 20, and caffeine were used to synthesize two samples of PU structures, one with and one without rose extract. The structures’ shape, size and surface charge, encapsulation efficacy, pH, solubility, release kinetics, and permeation rate were all assessed; the irritation potential of samples was verified by skin parameters testing the cytotoxicity by in vitro cell viability assay. Results: Within our findings, structures measuring between 98 and 203 nm were found, while the sample containing the rose extract showed an entrapment efficacy of 71.76%. Almost 90% of the structures penetrated the membrane in 48 h, and around 45% were released from the carrier in the same period. Biosafety evaluations conducted both in vivo and in vitro confirmed that PU structures are safe as delivery vehicles. Conclusions: This study shows the potential of polyurethane structures with rose extracts for use in biomedical applications and cosmetics. However, more research is needed to examine the clinical testing of polyurethane delivery systems and optimize release kinetics and permeation rates for particular therapeutic uses. Full article

This study developed bio-based waterborne polyurethane (BWPU) dispersions containing lignin as a sustainable filler with castor oil (CO), polycaprolactone diol (PCL), or poly(trimethylene ether) glycol (PO3G). The effects of the polyol structure and the presence of lignin on the mechanical performance, thermal stability, water absorption, ethanol resistance, and UV-blocking capabilities of the resulting BWPU samples were evaluated. The results revealed that lignin affects the molecular packing and interchain interactions of CO-based BWPU, thus improving its tensile strength and thermal stability while reducing its water absorption and ethanol permeability. In the PCL-based BWPU, lignin had a minimal impact on water absorption and ethanol resistance but led to greater UV-blocking ability due to interactions between the semi-crystalline matrix of PCL and the aromatic structure of the lignin. In the PO3G-based BWPU, lignin disrupted the polymer network, increasing its water absorption and reducing its ethanol resistance but significantly improving its elongation and UV-shielding behavior. These results highlight the dual role of lignin as a sustainable reinforcing agent and functional additive in enhancing the properties of BWPU. By tailoring the polyol structure and optimizing lignin use, this study demonstrates a framework for the development of eco-friendly PU composites suitable for use as coatings, barriers, UV-shielding films, and packaging Full article

Background and Objectives: Nucleotide delivery has emerged as a noteworthy research trend in recent years because of its potential utility in addressing a range of genetic defects resulting in the presence of incorrect nucleotides. The primary goals of this research were to create and to characterize polyurethane microstructures, with the aim of utilizing them for nucleotide transport. Materials and Methods: Two samples were prepared using an aliphatic diisocyanate in reaction with a mixture of polyethylene glycol and polycaprolactone diol, where 2′-deoxycytidinic acid was used as the active agent and glycerol 1,2-diacetate was used as an enhancer of the aqueous solubility. The solubility, pH, size distribution, and surface charge of the samples were measured, and encapsulation efficacy and release, cell proliferation, and irritation tests on mouse skin were conducted. Results: The results showed almost neutral acidic–basic structures with a high heterogeneity, and a medium tendency to form clusters with non-cytotoxic and non-irritative potentials. Conclusions: Future research could explore the efficacy of this carrier in delivering other nucleotides, as well as investigating the long-term effects and safety of these microstructures in vivo. Full article

Biodegradable thin films based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(caprolactone diol) (PCL-diol) blend were developed using the solution casting method. PHBV is biodegradable, biocompatible, and produced naturally by bacterial activity, but its use is restricted by high crystallinity and low resistance to thermal degradation with melting temperatures close to degradation thus narrowing the processing window. Solution casting was chosen as a cost-effective method reducing energy consumption and avoiding thermal degradation during processing. The increase in PCL-diol in blend composition (40–60 wt%) enhances the film-forming ability of PHBV and the wettability along with the decrease in the roughness of the resulting materials as revealed by contact angle measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Optimal composition in terms of filmogenity and surface structure has been achieved by the addition of PCL-diol in the amount of 60 wt%. FTIR confirmed the expected chemical structures with no evidence of chemical interactions between the two polymers. Full article

The progressive trend of utilizing bioactive materials constitutes diverse materials exhibiting biocompatibility. The innovative aspect of this research is the tuning of the thermo-mechanical behavior of polyurethane (PU) composites with improved biocompatibility for vibrant applications. Polycaprolactone (CAPA) Mn = 2000 g-mol⁻¹ was used as a macrodiol, along with toluene diisocyanate (TDI) and hexamethylene diisocyanate (HMDI), to develop prepolymer chains, which were terminated with 1,4 butane diol (BD). The matrix was reinforced with various concentrations of chitosan (1–5 wt %). Two series of PU composites (PUT/PUH) based on aromatic and aliphatic diisocyanate were prepared by varying the hard segment (HS) ratio from 5 to 30 (wt %). The Fourier-transformed infrared (FTIR) spectroscopy showed the absence of an NCO peak at 1730 cm⁻¹ in order to confirm polymer chain termination. Thermal gravimetric analysis (TGA) showed optimum weight loss up to 500 °C. Dynamic mechanical analysis (DMA) showed the complex modulus (E*) ≥ 200 MPa. The scanning electron microscope (SEM) proved the ordered structure and uniform distribution of chain extender in PU. The hemolytic activities were recorded up to 15.8 ± 1.5% for the PUH series. The optimum values for the inhibition of biofilm formation were recorded as 46.3 ± 1.8% against E. coli and S. aureus (%), which was supported by phase contrast microscopy. Full article

The delivery of nucleosides represents an interesting research trend in recent years due to their application in various viral infections. The main aims of this study were to develop and to characterize polyurethane particles that are intended to be used for the transport of nucleosides. Three samples have been prepared using aliphatic diisocyanates, a mixture of polyethylene glycol, polycaprolactone, and diols, respectively. The samples were characterized through refractivity measurements, drug loading efficacy, release and penetration rate investigations, FTIR and Raman spectroscopy, thermal analyses, Zetasizer, SEM, HDFa cells viability, and irritation tests on mice skin. The results indicate the obtaining of particles with sizes between 132 and 190 nm, positive Zeta potential values (28.3–31.5 mV), and a refractivity index around 1.60. A good thermal stability was found, and SEM images show a medium tendency to agglomerate. The samples’ color, pH, and electrical conductivity have changed only to a small extent over time, and the evaluations indicate an almost 70% encapsulation efficacy, a prolonged release, and that around 70% of particles have penetrated an artificial membrane in the first 24 h. The synthesized products should be tested in further clinical trials, and the current tests on cell cultures and mice skin revealed no side effects. Full article

In this work, we explore the influence of soft segment structure on the crystallinity and phase separation of semicrystalline multi-block thermoplastic polyurethanes (TPUs) based on poly(butylene adipate) diol, polycaprolactone diol, and their mixture. According to thermal and structural analyses, the crystal growth rate and degree of crystallinity decrease with an increase in the PCL/PBA ratio and reach a minimum at the equimolar composition of polyesters. A reduction in crystal phase content leads to an improvement in elastomeric behavior. TPU samples with high PCL content demonstrate enhanced crystallinity but a lower melting temperature compared to TPU with PBA crystals. Crystallization of TPU below room temperature results in an enhancement of total crystallinity and a change in the phase composition of the PBA block. The difference in semicrystalline morphology and crystallization kinetics can be explained by the efficiency of phase separation and the density of hydrogen bonding between soft and hard segments. Our findings show that the ratio of the two crystallizable polyesters, combined with the choice of crystallization temperature, allows for independent control over the melting temperature and the overall degree of crystallinity of the TPUs. This significantly impacts the mechanical characteristics of the materials. The effect of adding a second crystallizable polyester on the crystallization behavior, phase composition, and mechanical properties of TPU is discussed for the first time. Full article

A series of polyurethanes (PU) were synthesised via one-step polymerisation without a chain extender, using toluene diisocyanate as well as a variety of soft segments composed of different macrodiols. Poly(D,L-lactide) (PDLLA) and polycaprolactone diol (PCL) were synthesised as a polyester type polyols to obtain soft segments. The process of varying the molar ratio of newly synthesised PDLLA in soft segments has been confirmed as a powerful tool for fine-tuning the final properties of PU. Fourier-transformed infrared spectroscopy was used for evaluation of molecular structures of synthesised PDLLA polyol and final PU. Nuclear magnetic resonance spectrometry was used to confirm the presumed structure of PU. The influence of soft segment composition on polyurethane thermal characteristics was examined using thermogravimetric analysis and differential scanning calorimetry. The composition of soft segments had little impact on the thermal stability of PU materials, which is explained by the comparable structures of both polyester polyols. Wide-angle X-ray scattering was utilised to evaluate the effect of amorphous PDLLA on the degree of crystallinity of PCL in soft PU segments. It was discovered that not only did the PDLLA ratio in the soft segment have a substantial influence on the degree of microphase separation in the soft and hard segments, but it also influenced the crystallisation behaviour of the materials. Furthermore, the restriction of crystallisation of the PCL soft segment has been verified to be dependent on the hard segment concentration and the ratio of PDLLA/PCL polyols. The sample with pure PCL as the polyol component achieved the highest degree of crystallinity (34.8%). The results demonstrated that the composition of soft segments directly affected the properties of obtained polyurethane films. These results can be utilised to easily achieve a desirable set of properties required for application in biomaterials. Full article

In this work, 3D printed polylactic acid (PLA)/polycaprolactone (PCL) nanocomposites with favorable thermo-responsive cyclic shape memory effects (SMEs) and crystallization and mechanical properties were fabricated using a two-step method. First, an isocyanate-terminated PCL diol (PCL-NCO) was synthesized through the reaction between isocyanate groups of hexamethylene diisocyanate and active hydroxyl groups of PCL diol, and its physicochemical properties were characterized. A PLA/PCL blend with a PCL content of 50 wt% was fabricated via fused filament fabrication (FFF) 3D printing, and the influence of the PCL-NCO on the SME of the PLA/PCL blend was studied. The results indicated that the PCL-NCO significantly improved the cyclic shape memory performance of 3D printed PLA/PCL blends and was proved to be an effective interface compatibilizer for the blend system. Subsequently, the structure and properties of 3D printed PLA/PCL nanocomposites were investigated in detail by adding cellulose nanocrystal-organic montmorillonite (CNC-OMMT) hybrid nanofillers with different contents. It was found that the hybrid nanofillers greatly enhanced crystallization and mechanical properties of the nanocomposites due to adequate dispersion. The modification of the PLA/PCL blend and the preparation of the 3D printed nanocomposite can not only prolong the service life of a shape memory polymer product, but also broaden its application scope in advanced fields. Full article

Quercetin is a hydrophobic molecule with short blood circulation times and instability. The development of a nano-delivery system formulation of quercetin may increase its bioavailability, resulting in greater tumor suppressing effects. Triblock ABA type polycaprolactone-polyethylenglycol- polycaprolactone (PCL-PEG-PCL) copolymers have been synthetized using ring-opening polymerization of caprolactone from PEG diol. The copolymers were characterized by nuclear magnetic resonance (NMR), diffusion-ordered NMR spectroscopy (DOSY), and gel permeation chromatography (GPC). The triblock copolymers self-assembled in water forming micelles consisting of a core of biodegradable polycaprolactone (PCL) and a corona of polyethylenglycol (PEG). The core-shell PCL-PEG-PCL nanoparticles were able to incorporate quercetin into the core. They were characterized by dynamic light scattering (DLS) and NMR. The cellular uptake efficiency of human colorectal carcinoma cells was quantitatively determined by flow cytometry using nanoparticles loaded with Nile Red as hydrophobic model drug. The cytotoxic effect of quercetin-loaded nanoparticles was evaluated on HCT 116 cells, showing promising results. Full article

A novel series of biodegradable polylactide-based triblock polyurethane (TBPU) copolymers covering a wide range of molecular weights and compositions were synthesized for potential use in biomedical applications. This new class of copolymers showed tailored mechanical properties, improved degradation rates, and enhanced cell attachment potential compared to polylactide homopolymer. Triblock copolymers, (TB) PL-PEG-PL, of different compositions were first synthesized from lactide and polyethylene glycol (PEG) via ring-opening polymerization in the presence of tin octoate as the catalyst. After which, polycaprolactone diol (PCL-diol) reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as a nontoxic chain extender to form the final TBPUs. The final composition, molecular weight, thermal properties, hydrophilicity, and biodegradation rates of the obtained TB copolymers, and the corresponding TBPUs were characterized using ¹H-NMR, GPC, FTIR, DSC, and SEM, and contact angle measurements. Results obtained from the lower molecular weight series of TBPUs demonstrated potential use in drug delivery and imaging contrast agents due to their high hydrophilicity and degradation rates. On the other hand, the higher molecular weight series of TBPUs exhibited improved hydrophilicity and degradation rates compared to PL-homopolymer. Moreover, they displayed improved tailored mechanical properties suitable for utilization as bone cement, or in regeneration medicinal applications of cartilage, trabecular, and cancellous bone implants. Furthermore, the polymer nanocomposites obtained by reinforcing the TBPU3 matrix with 7% (w/w) bacterial cellulose nanowhiskers (BCNW) displayed a ~16% increase in tensile strength, and 330% in % elongation compared with PL-homo polymer. Full article

In this study, a high-performance H₂S sensor that operates at RT was successfully fabricated using biodegradable electroactive polymer-polyurethane-urea (PUU) and PUU-activated-carbon (AC) composites as sensitive material. The PUU was synthesized through the copolymerization of biodegradable polycaprolactone diol and an electroactive amine-capped aniline trimer. AC, with a large surface area of 1620 m²/g and a pore diameter of 2 nm, was derived from coconut-shell waste. The composites, labeled PUU-AC1 and PUU-AC3, were prepared using a physical mixing method. The H₂S-gas-sensing performance of PUU-AC0, PUU-AC1, and PUU-AC3 was evaluated. It was found that the PUU sensor demonstrated good H₂S-sensing performance, with a sensitivity of 0.1269 ppm⁻¹ H₂S. The H₂S-gas-sensing results indicated that the PUU-AC composites showed a higher response, compared with PUU-AC0. The enhanced H₂S-response of the PUU-AC composites was speculated to be due to the high surface-area and abounding reaction-sites, which accelerated gas diffusion and adsorption and electron transfer. When detecting trace levels of H₂S gas at 20 ppm, the sensitivity of the sensors based on PUU-AC1 and PUU-AC3 increased significantly. An observed 1.66 and 2.42 times’ enhancement, respectively, in the sensors’ sensitivity was evident, compared with PUU-AC0 alone. Moreover, the as-prepared sensors exhibited significantly high selectivity toward H₂S, with minimal to almost negligible responses toward other gases, such as SO₂, NO₂, NH₃, CO, and CO₂. Full article

A series of semi-crystalline multi-block thermoplastic polyurethanes (TPU), containing poly(butylene adipate) (PBA), polycaprolactone (PCL) and their equimolar mixture (PBA/PCL) as a soft segment was synthesized. The changes in the physical-mechanical and thermal properties of the materials observed in the course of a 36-month storage at room temperature were related to the corresponding structural evolution. The latter was monitored using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXS) and mechanical tests (tensile strength test). The effects of the composition of the soft segment on the phase separation and crystallization of the soft segment were analyzed in detail. It was found that the melting temperature of the crystalline phase increases with storage time, which is associated with hindering of the phase separation of the hard and soft segments of the TPU samples as it was detected by FTIR. Full article

Biofilms are known to be difficult to eradicate and control, complicating human infections and marine biofouling. In this study, self-polishing and anti-fouling waterborne polyurethane coatings synthesized from gemini quaternary ammonium salts (GQAS), polyethylene glycol (PEG), and polycaprolactone diol (PCL) demonstrate excellent antibiofilm efficacy. Their anti-fouling and anti-biofilm performance was confirmed by a culture-based method in broth media, with the biofilm formation factor against Gram-positive (S. aureus) and Gram-negative bacterial strains (E. coli) for 2 days. The results indicate that polyurethane coatings have excellent anti-biofilm activity when the content of GQAS reached 8.5 wt% against S. aureus, and 15.8 wt% against E. coli. The resulting waterborne polyurethane coatings demonstrate both hydrolytic and enzymatic degradation, and the surface erosion enzymatic degradation mechanism enables them with good self-polishing capability. The extracts cyto-toxicity of these polyurethane coatings and degradation liquids was also systematically studied; they could be degraded to non-toxic or low toxic compositions. This study shows the possibility to achieve potent self-polishing and anti-biofilm efficacy by integrating antibacterial GQAS, PEG, and PCL into waterborne polyurethane coatings. Full article