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Acta Biomaterialia May 2024Osteoarthritis (OA) poses significant therapeutic challenges, particularly OA that affects the hand. Currently available treatment strategies are often limited in terms...
Osteoarthritis (OA) poses significant therapeutic challenges, particularly OA that affects the hand. Currently available treatment strategies are often limited in terms of their efficacy in managing pain, regulating invasiveness, and restoring joint function. The APRICOT implant system developed by Aurora Medical Ltd (Chichester, UK) introduces a minimally invasive, bone-conserving approach for treating hand OA (https://apricot-project.eu/). By utilizing polycarbonate urethane (PCU), this implant incorporates a caterpillar track-inspired design to promote the restoration of natural movement to the joint. Surface modifications of PCU have been proposed for the biological fixation of the implant. This study investigated the biocompatibility of PCU alone or in combination with two surface modifications, namely dopamine-carboxymethylcellulose (dCMC) and calcium-phosphate (CaP) coatings. In a rat soft tissue model, native and CaP-coated PCU foils did not increase cellular migration or cytotoxicity at the implant-soft tissue interface after 3 d, showing gene expression of proinflammatory cytokines similar to that in non-implanted sham sites. However, dCMC induced an amplified initial inflammatory response that was characterized by increased chemotaxis and cytotoxicity, as well as pronounced gene activation of proinflammatory macrophages and neoangiogenesis. By 21 d, inflammation subsided in all the groups, allowing for implant encapsulation. In a rat bone model, 6 d and 28 d after release of the periosteum, all implant types were adapted to the bone surface with a surrounding fibrous capsule and no protracted inflammatory response was observed. These findings demonstrated the biocompatibility of native and CaP-coated PCU foils as components of APRICOT implants. STATEMENT OF SIGNIFICANCE: Hand osteoarthritis treatments require materials that minimize irritation of the delicate finger joints. Differing from existing treatments, the APRICOT implant leverages polycarbonate urethane (PCU) for minimally invasive joint replacement. This interdisciplinary, preclinical study investigated the biocompatibility of thin polycarbonate urethane (PCU) foils and their surface modifications with calcium-phosphate (CaP) or dopamine-carboxymethylcellulose (dCMC). Cellular and morphological analyses revealed that both native and Ca-P coated PCU elicit transient inflammation, similar to sham sites, and a thin fibrous encapsulation in soft tissues and on bone surfaces. However, dCMC surface modification amplified initial chemotaxis and cytotoxicity, with pronounced activation of proinflammatory and neoangiogenesis genes. Therefore, native and CaP-coated PCU possess sought-for biocompatible properties, crucial for patient safety and performance of APRICOT implant.
PubMed: 38815684
DOI: 10.1016/j.actbio.2024.05.042 -
RSC Advances May 2024Traditionally, waterborne polyurethanes (WPUs) are prepared using toxic organic solvents and catalysts. These WPUs are non-biodegradable and are buried or incinerated...
Traditionally, waterborne polyurethanes (WPUs) are prepared using toxic organic solvents and catalysts. These WPUs are non-biodegradable and are buried or incinerated after the expiration date. This has adverse effects on the environment and human health, which limits the applications of WPUs. Herein, a special synthetic method was developed for biodegradable waterborne polyurethane (BWPU) by adding hydrophilic prepolymers into WPU prepolymers without using organic solvents and catalysts. Different proportions of polyethylene glycol (PEG) were introduced into polycaprolactone (PCL)-based BWPUs to improve the comprehensive properties. Results showed that as the PEG content was increased from 0 to 16 wt%, the solid content of BWPU increased from 34.8 wt% to 53.1 wt%, while the tensile strength and Young's modulus of BWPU films increased from 21.81 MPa to 56.83 MPa and 8.08 MPa to 19.4 MPa, respectively. However, the elongation at break did not decrease significantly, but still reached 827.17%. With an increase in PEG content, the crystallinity and phase separation decreased, while the hydrophilicity and surface energy increased for BWPU films. In addition, the prepared BWPUs had good biodegradability in PBS/lipase solution. The mass loss of BWPU without PEG reached 6.3 wt% after 4 weeks of degradation, whereas the mass losses of BWPUs with PEG reached 2.3-4.3 wt%. Obviously, the introduction of PEG did not increase biodegradability. Thus, the higher the PCL content, the faster the biodegradation rate. This work would provide an effective method for the preparation of ecofriendly biodegradable BWPU with excellent comprehensive properties.
PubMed: 38813130
DOI: 10.1039/d4ra02044h -
Nature Communications May 2024Porous materials with ultrahigh specific strength are highly desirable for aerospace, automotive and construction applications. However, because of the harsh processing...
Porous materials with ultrahigh specific strength are highly desirable for aerospace, automotive and construction applications. However, because of the harsh processing of metal foams and intrinsic low strength of polymer foams, both are difficult to meet the demand for scalable development of structural foams. Herein, we present a supramolecular metallic foam (SMF) enabled by core-shell nanostructured liquid metals connected with high-density metal-ligand coordination and hydrogen bonding interactions, which maintain fluid to avoid stress concentration during foam processing at subzero temperatures. The resulted SMFs exhibit ultrahigh specific strength of 489.68 kN m kg (about 5 times and 56 times higher than aluminum foams and polyurethane foams) and specific modulus of 281.23 kN m kg to withstand the repeated loading of a car, overturning the previous understanding of the difficulty to achieve ultrahigh mechanical properties in traditional polymeric or organic foams. More importantly, end-of-life SMFs can be reprocessed into value-added products (e.g., fibers and films) by facile water reprocessing due to the high-density interfacial supramolecular bonding. We envisage this work will not only pave the way for porous structural materials design but also show the sustainable solution to plastic environmental risks.
PubMed: 38811594
DOI: 10.1038/s41467-024-49091-6 -
Scientific Reports May 2024Repair and reconstruction of the myopectineal orifice area using meshes is the mainstay of surgical treatment of inguinal hernias. However, the limitations of existing...
Repair and reconstruction of the myopectineal orifice area using meshes is the mainstay of surgical treatment of inguinal hernias. However, the limitations of existing meshes are becoming increasingly evident in clinical applications; thus, the idea of using three-dimensionally (3D)-printed biological meshes was put forward. According to the current level of the 3D printing technology and the inherent characteristics of biological materials, the direct use of the 3D printing technology for making biological materials into finished products suitable for clinical applications is not yet supported, but synthetic materials can be first printed into 3D form carriers, compounded with biological materials, and finally made into finished products. The purpose of this study was to develop a technical protocol for making 3D-printed biomesh carriers using polyurethane as a raw material. In our study: raw material, polyurethane; weight, 20-30 g/m; weaving method, hexagonal mesh; elastic tension aspect ratio, 2:1; diameters of pores, 0.1-1 mm; surface area, 8 × 12 cm; the optimal printing layer height, temperature and velocity were 0.1 mm, 210-220 °C and 60 mm/s. Its clinical significance lies in: (1) applied to preoperative planning and design a detailed surgical plan; (2) applied to special types of surgery including patients in puberty, recurrent and compound inguinal hernias; (3) significantly improve the efficiency of doctor-patient communication; (4) it can shorten the operation and recovery period by about 1/3 and can save about 1/4 of the cost for patients; (5) the learning curve is significantly shortened, which is conducive to the cultivation of reserve talents.
Topics: Printing, Three-Dimensional; Polyurethanes; Surgical Mesh; Humans; Hernia, Inguinal; Biocompatible Materials; Herniorrhaphy; Materials Testing
PubMed: 38806559
DOI: 10.1038/s41598-024-63000-3 -
ACS Biomaterials Science & Engineering Jun 2024The development of precision polymer synthesis has facilitated access to a diverse library of abiotic structures wherein chiral monomers are positioned at specific...
The development of precision polymer synthesis has facilitated access to a diverse library of abiotic structures wherein chiral monomers are positioned at specific locations within macromolecular chains. These structures are anticipated to exhibit folding characteristics similar to those of biotic macromolecules and possess comparable functionalities. However, the extensive sequence space and numerous variables make selecting a sequence with the desired function challenging. Therefore, revealing sequence-function dependencies and developing practical tools are necessary to analyze their conformations and molecular interactions. In this study, we investigate the effect of stereochemistry, which dictates the spatial location of backbone and pendant groups, on the interaction between sequence-defined oligourethanes and bisphenol A ligands. Various methods are explored to analyze the receptor-like properties of model oligomers and the ligand. The accuracy of molecular dynamics simulations and experimental techniques is assessed to uncover the impact of discrete changes in stereochemical arrangements on the structures of the resulting complexes and their binding strengths. Detailed computational investigations providing atomistic details show that the formed complexes demonstrate significant structural diversity depending on the sequence of stereocenters, thus affecting the oligomer-ligand binding strength. Among the tested techniques, the fluorescence spectroscopy data, fitted to the Stern-Volmer equation, are consistently aligned with the calculations, thus validating the developed simulation methodology. The developed methodology opens a way to engineer the structure of sequence-defined oligomers with receptor-like functionality to explore their practical applications, e.g., as sensory materials.
Topics: Ligands; Polyurethanes; Stereoisomerism; Molecular Dynamics Simulation; Benzhydryl Compounds; Phenols
PubMed: 38804015
DOI: 10.1021/acsbiomaterials.4c00456 -
ACS Omega May 2024A novel nontoxic method for processing energetic binder, namely, polyglycidyl nitrate (PGN), using Aza-Michael reactions for deriving high-performance explosive...
A novel nontoxic method for processing energetic binder, namely, polyglycidyl nitrate (PGN), using Aza-Michael reactions for deriving high-performance explosive formulations is being reported. The polyol binders used in polymer-bonded explosives (PBX) including PGN are usually cross-linked using isocyanate leading to polyurethane (PU)-based cured solid networks. These reactions require mild reaction conditions and yield good mechanical properties for the PBX but remain challenging due to extraneous reactions of isocyanate resulting in defects in the cured blocks. In addition, the presence of nitrato groups in the vicinity of terminal hydroxyl groups of PGN results in the decuring of cross-linked urethane that affects the storage life of PBX, though PGN-based binder can provide an 18% improvement in the velocity of detonation of PBX at lower solid loadings of 70%. This prevents researchers from exploiting the major performance advantage of using PGN for PBX compositions. This article herein features a green and mild aza-Michael reaction for functional modification of PGN using readily available substrates and triethylene tetramine to form a cross-linked β-aminocarbonyl network. The methodology ensures a void-free, stable, cured network and offers an effective replacement for toxic cure chemistry currently employed for processing of PBX.
PubMed: 38799311
DOI: 10.1021/acsomega.4c00349 -
Bioactive Materials Aug 2024Clinical use of small-diameter vascular grafts remains a challenging issue in neovessel regeneration in view of thrombosis and intimal hyperplasia. Developing a vascular...
Clinical use of small-diameter vascular grafts remains a challenging issue in neovessel regeneration in view of thrombosis and intimal hyperplasia. Developing a vascular graft with structure and function similar to those of the native vessels necessitates a major direction of vascular tissue regeneration. Thus, this study sought to design and fabricate a range of tri-phasic scaffolds (0, 2, and 5 wt% gastrodin-polyurethane (PU)) with spatiotemporally defined structure and gastrodin-release for regulating the highly coordinated processes in growth of the intima and media. While the small pores of inner layer guided infiltration of human umbilical vein endothelial cells (HUVECs), the bigger pores of medial layer could offer smooth muscle cell (SMC)-friendly habitat, and external fibers conferred adequate mechanical properties. Correspondingly, spatial distribution and differential regulation of key proteins in HUVECs and SMCs were mediated by hierarchical release of gastrodin, of which rapid release in inner layer elicited enhanced HUVEC proliferation and migration against those of the SMC activated endothelial nitric oxide synthase (eNOS) and heat shock protein 70 (HSP70) signal. Of note, superior anti-coagulation was reflected in 2 wt% gastrodin-PU extracorporeal blood circulation experiment. After implantation for 12 weeks, there was no formation of obvious thrombosis and intimal hyperplasia in 2 wt% gastrodin-PU. The scaffold maintained high patency and improved vascular remodeling, including the formation of thin endothelialization in lumen and dense extracellular matrix deposition in medial layer. Taken together, the results demonstrate the positive function of hierarchical releasing system that responded to tri-phasic structure, which not only suppressed intimal thickening but also tightly controlled tissue regeneration.
PubMed: 38798891
DOI: 10.1016/j.bioactmat.2024.05.007 -
International Journal of Biological... Jun 2024The amelioration of refractory diabetic ulcers presents a formidable conundrum on a global scale, attributable to the elevated peril of contagion and protracted...
The amelioration of refractory diabetic ulcers presents a formidable conundrum on a global scale, attributable to the elevated peril of contagion and protracted convalescence durations. Within the purlieus of this reparative epoch, the deployment of efficacious wound coverings endowed with both angiogenesis and antibacterial attributes is of paramount significance. Hydrogel wound dressings are distinguished by their elevated biocompatibility, adhesive tenacity, and innate regenerative capacity. Eugenol, a substance distilled from the blossoms of the lilac, serves as a precursor to metformin and is known to impede the genesis of reactive oxygen species. Although its antibacterial effects have been extensively chronicled, the angiogenic ramifications of eugenol within the context of wound remediation remain under-investigated. This research aimed to evaluate the effectiveness of eugenol-infused hydrogel as a wound dressing material. In this context, polyurethane gelatin (PG) was combined with eugenol at concentrations of 0.5% and 1%, creating PG-eugenol hydrogel mixtures with specific mass ratios for both in vivo and in vitro assessments. The in vivo studies indicated that hydrogels infused with eugenol expedited diabetic wound healing by fostering angiogenesis. Enhanced healing was noted, attributed to improved antibacterial and angiogenic properties, increased cell proliferation, tissue regeneration, and re-epithelialization. The in vitro analyses revealed that eugenol-enriched hydrogels stimulated the growth of fibroblasts (HFF-1) and human umbilical vein endothelial cells (HUVECs) and exhibited antibacterial characteristics. This investigation confirms the potential of eugenol-laden hydrogels in effectively treating diabetic wound defects.
Topics: Eugenol; Wound Healing; Polyurethanes; Anti-Bacterial Agents; Gelatin; Animals; Neovascularization, Physiologic; Bandages; Rats; Hydrogels; Male; Humans; Diabetes Mellitus, Experimental; Cell Proliferation; Human Umbilical Vein Endothelial Cells; Angiogenesis
PubMed: 38795896
DOI: 10.1016/j.ijbiomac.2024.132619 -
Polymers May 2024Decreasing oil resources creates the need to search for raw materials in the biosphere, which can be converted into polyols suitable for obtaining polyurethane foams...
Decreasing oil resources creates the need to search for raw materials in the biosphere, which can be converted into polyols suitable for obtaining polyurethane foams (PUF). One such low-cost and reproducible biopolymer is cellulose. There are not many examples of cellulose-derived polyols due to the sluggish reactivity of cellulose itself. Recently, cellulose and its hydroxypropyl derivatives were applied as source materials to obtain polyols, further converted into biodegradable rigid polyurethane foams (PUFs). Those PUFs were flammable. Here, we describe our efforts to modify such PUFs in order to decrease their flammability. We obtained an ester from diethylene glycol and phosphoric(III) acid and used it as a reactive flame retardant in the synthesis of polyol-containing hydroxypropyl derivative of cellulose. The cellulose-based polyol was characterized by infrared spectra (IR) and proton nuclear magnetic resonance (H-NMR) methods. Its properties, such as density, viscosity, surface tension, and hydroxyl numbers, were determined. Melamine was also added to the foamed composition as an additive flame retardant, obtaining PUFs, which were characterized by apparent density, water uptake, dimension stability, heat conductance, compressive strength, and heat resistance at 150 and 175 °C. Obtained rigid PUFs were tested for flammability by determining oxygen index, horizontal flammability test, and calorimetric analysis. Obtained rigid PUFs showed improved flammability resistance in comparison with non-modified PUFs and classic PUFs.
PubMed: 38794632
DOI: 10.3390/polym16101438 -
Polymers May 2024Polyurethane (PU) is a type of polymer, which exists in various forms in the environment. Very few studies are available concerning the structure or enzymatic mechanism...
Polyurethane (PU) is a type of polymer, which exists in various forms in the environment. Very few studies are available concerning the structure or enzymatic mechanism of the microbial community, which can degrade PU. Degradation of PU remains a difficult problem with respect to the environmental and biological disciplines. This study mainly focused on identifying the micro-organisms able to degrade polyurethane and confirming the degradation by performing a plate assay, Sturm test and scanning electron microscopy. Optimal culture conditions for maximum PU degradation were also analyzed through classical methods. A soil burial test was conducted by placing polyurethane films in the soil for one month, and the microbe growing on the surface of polyurethane films-with a maximum degradation of 55%-was isolated and identified as (ARF5). The culture medium was also optimized with different physical and chemical parameters for maximum PU degradation. The presence of CO as a by-product of PU biodegradation was confirmed through the Sturm test.
PubMed: 38794604
DOI: 10.3390/polym16101411