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Retinal degenerative diseases are a leading cause of vision loss and blindness globally, impacting millions. These diseases result from progressive damage to retinal pigment epithelial (RPE) cells for which no curative or palliative treatments exist. Cell therapy, particularly RPE transplantation, has emerged as a promising strategy for vision restoration. This review provides a comprehensive overview of the recent advancements in clinical trials related to RPE transplantation. We discuss scaffold-free and scaffold-based approaches, including RPE cell suspensions and pre-organized RPE monolayers on biomaterial scaffolds. Key considerations, such as the form and preparation of RPE implants, delivery devices, strategies, and biodegradability of scaffolds, are examined. The article also explores the challenges and opportunities in RPE scaffold development, emphasising the crucial need for functional integration, immunomodulation, and long-term biocompatibility to ensure therapeutic efficacy. We also highlight ongoing efforts to optimise RPE transplantation methods and their potential to address retinal degenerative diseases. [ABSTRACT FROM AUTHOR]

This review article delves into the development of electrolytes for flexible zinc-air batteries (FZABs), a critical component driving the advancement of flexible electronics. We started by surveying the current advancements in electrolyte technologies, including solid-state and gel-based types, and their contributions to enhance the flexibility, efficiency, and durability of FZABs. Secondly, we explored the challenges in this domain, focusing on maintaining electrolyte stability under mechanical stress, ensuring compatibility with flexible substrates, optimizing ion conductivity, and under harsh environmental conditions. Furthermore, the key issues regarding interface details between electrolyte and the electrodes are covered as well. We then discussed the future of electrolyte development in FZABs, highlighting potential avenues such as materials development, sustainability, in-situ studies, and battery integration. This review offers an in-depth overview of the advancements, challenges, and potential breakthroughs in creating electrolytes for FZABs over the past five years. It serves as a guide for both researchers and industry professionals in this dynamic area. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) have been widely recognized as efficient solutions for thermal management across various industries, including logistics, construction, electronics, and others. Nevertheless, these materials encounter challenges such as leakage, poor thermal conductivity, and supercooling. To address these challenges, a comprehensive examination was conducted on the recent advancements pertaining to silicon‐based materials. These studies include their application as high temperature PCMs, as encapsulation matrices, and their integration as additives to enhance material properties. Aluminum–silicon (Al−Si) alloys offer a viable thermal management solution for high‐temperature applications, such as those found in car batteries. Silicon dioxide (SiO2), silicon carbide (SiC), and silicate‐based minerals have demonstrated the ability to synergistically encapsulate PCMs to prevent leakage, enhance thermal conductivity, and mitigate supercooling. However, the efficacy of these strategies in reducing supercooling varies, and a considerable number of studies have reported an exacerbation. Therefore, appropriate material selection and fine tuning for formulation are necessary. This review critically assesses silicon‐based materials as a component of PCM composite that have been developed over the years. Also, it presents an academic analysis of the selection of silicon‐based materials and the design strategy for PCM composites to optimize PCM formulations according to specific desired properties. [ABSTRACT FROM AUTHOR]

In response to the pressing issue of water pollution caused by heavy metal ions, there is a growing demand for green adsorbents that can effectively remove these contaminants while being easy to separate and regenerate. A novel magnetic composite was synthesized by bonding amino‐functionalized Fe3O4−SiO2 magnetic particles (MNP‐NH2) to polyethyleneimine (PEI)‐grafted cellulose nanofibers (CNF). The modification of CNF with PEI through a peptidic coupling reaction resulted in the uniform dispersion and strong attachment of MNP‐NH2 particles (286.7 nm) onto the PEI‐CNF surface. This composite exhibited exceptional adsorption capabilities for heavy metals, achieving 16.73 mg/g for Pb, 16.12 mg/g for Cu, and 12.53 mg/g for Co. These remarkable adsorption capacities are attributed to the complex interactions between the metal ions and the amino, carboxyl, and hydroxyl groups on the surface of PEI‐CNF‐MNP. The introduction of PEI significantly enhanced the adsorption capacities, and the adsorption sequence (Pb(II)>Cu(II)>Co(II)) can be explained by differences in ionic radius and surface complexation strength. Langmuir isotherm and pseudo‐second‐order kinetic models described the adsorption process, while Na2EDTA was proved effective for desorption with high recovery rates. This magnetic composite holds promise for treating heavy metal‐contaminated wastewater due to its impressive performance. [ABSTRACT FROM AUTHOR]

Designing nanocomposites with heterointerface as bifunctional electrocatalysts is a potential strategy to overcome the intrinsic activity limitation of electrocatalytic water splitting in acidic media, but it remains challenging. Herein, the highly efficient RuO2/Co3O4 electrocatalyst with a uniform nanoflower structure is prepared by hydrothermal growth combined with interface engineering. Benefiting from the unique nanostructure, the migration of electrons and intermediates is optimized by the sufficient exposure of abundant micropores and defects. Moreover, the formation of strong electronic interaction at the RuO2/Co3O4 heterointerfaces boosts the electrochemical active surface area and accelerates the reaction kinetics, which effectively improve the catalytic activity and stability of the catalyst. Based on enhanced intrinsic activity and electron transfer, the as‐synthesized RuO2/Co3O4 displays impressive hydrogen evolution reaction and oxygen evolution reaction activity, which respectively require low overpotentials of 240 and 100 mV to achieve a current density of 10 mA cm−2 in 0.5 m H2SO4. As a bifunctional electrode, RuO2/Co3O4 exhibits a low operating voltage of 1.58 V at 10 mA cm−2 for overall electrochemical water splitting. This study demonstrates the importance of heterostructure engineering in providing an avenue to achieve acid‐stable bifunctional electrocatalysts for energy conversion applications. [ABSTRACT FROM AUTHOR]

Antibacterial photodynamic therapy (aPDT) is emerging as an effective means of treating pathogenic bacteria, especially in light of the challenges posed by antibiotic resistance. SQR29, an organophotosensitizer, was encapsulated in a poly(lignin/PEG/PPG urethane) hydrogel to enable targeted treatment at a specific infected area. The hydrogel exhibited free radical scavenging properties which were effective in preventing oxidative stress and promoted wound healing. The hydrogel exhibited a significant aPDT effect on Gram-positive bacteria, hence showing its potential in combating antibiotic-resistant pathogenic bacteria in chronic wound infection. [ABSTRACT FROM AUTHOR]

Metal-support interaction has been used for selectivity control towards electro-chemical CO2 reduction reaction (CO2RR). However, little progress has been made in adjusting the size of metal nanoparticles in supporting material and its effect on CO2RR. Herein, we prepared Cu metal nanoparticle catalysts ranging from a few nanometers to tens in crystallite size encapsulated in Zn, N-doped carbon supports and systematically study the size effect of the supported Cu metal catalysts on the reactivity of CO2RR. The catalyst containing 15.7-nm Cu crystallites has a higher Faradaic efficiency (nearly 80%) at − 0.7 V vs. RHE for CO, higher than 12.2-nm and 8.9-nm Cu catalysts. The result shows the dependence of CO2RR performance on Cu metal size, originating from the interaction between metal nanoparticles and their supporting matrix. This work may shed light on the promise of in situ construction method for supported metal catalyst and the investigation of metal-support interaction towards stable and selective electrochemical CO2 reduction. Cu metal nanoparticle catalysts ranging from a few to tens of nanometers in crystallite size were encapsulated in Zn, N-doped carbon supports, of which the size effect and metal-support interaction regulates the reactivity of CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Aggregation of organic photothermal agents enhances their photothermal effect. Conventionally, aggregation is achieved by solvatochromic effects which is not translatable for photothermal applications. This report details the incorporation of an organic photosensitizer into a chitosan hydrogel which induced its aggregation, enhancing its photothermal effect and feasibility for its intended applications. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Polymer electrolytes for flexible zinc-air batteries: Recent progress and future directions" published in the journal Nano Research. The correction addresses an error in the name and affiliation of the seventh author, Janet Beng Hoon Tan. The corrections have been made to the online version of the original article. The article discusses the progress and future directions of polymer electrolytes for flexible zinc-air batteries. The authors are affiliated with various institutions in Singapore. [Extracted from the article]

There has been increasing exploration of the development and production of biodegradable polymers in response to issues with petrol‐based polymers and their impact on the environment. Here we report a new approach to synthesize a natural nanogel from lignin and nanocellulose. First, lignin nanobeads were synthesized by a solvent‐shifting method, which showed a spherical shape with a diameter of 159.7 nm. Then the lignin nanobeads were incorporated into a nanocellulose network to form the lignin/cellulose nanogels. The nanocellulose fibrils (CNF−C) nanogels reveal a higher storage modulus than the nanocellulose crystal (CNC−C) ones due to the denser network with self‐entanglement of longer cellulose chains. The presence of lignin nanobeads in the nanogels helped to increase the viscoelasticity of the nanogels. This work highlights that the new kinds of green nanogels could be potentially utilized in a variety of biomedical applications such as drug delivery and wound dressing. [ABSTRACT FROM AUTHOR]

Supramolecular hydrogels have attracted considerable interest due to their unique stimuli‐responsive and self‐healing properties. However, these hydrogel systems are usually achieved by covalent grafting of supramolecular units onto the polymer backbone, which in turn limits their reprocessability. Herein, we prepared a supramolecular hydrogel system by forming dynamic covalent crosslinks between 4‐carboxyphenylboronic acid (CPBA) and polyvinyl alcohol (PVA). The system was then further crosslinked with either calcium ions or branched polyethylenimine (PEI) to generate hydrogels with distinctly different properties. Incorporation of calcium ions resulted in the formation of hydrogels with higher storage modulus of 7290 Pa but without self‐healing properties. On the other hand, PEI‐crosslinked hydrogel (PVA‐CPBA‐PEI) exhibited >2000% critical strain value, demonstrated high stability over 52 days and showed sustained antibacterial effect. A combination of supramolecular interactions and dynamic covalent crosslinks can be an alternate strategy to fabricate next‐generation hydrogel materials. [ABSTRACT FROM AUTHOR]

Background: Cabazitaxel significantly improves clinical outcomes compared with a second androgen receptor-targeted agent (ARTA) in patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with docetaxel and an ARTA (abiraterone or enzalutamide), as demonstrated in the CARD trial (NCT02485691). We aimed to estimate healthcare costs avoided with the use of cabazitaxel as a third-line (3 L) treatment versus a second ARTA from a US payer perspective.Methods: Model inputs were based on the CARD trial, published sources, and estimates of typical clinical care patterns by genitourinary oncologists (n = 3). Assessed time points were 6, 12, 18, and 24 months. Outcomes included progression-free survival (PFS), radiographic PFS (rPFS), and overall survival (OS); hospitalization and intensive care unit (ICU) days; and costs (reported in 2020 US dollar [USD] and converted into Euro) to manage symptomatic skeletal events (SSEs), adverse events (AEs), and end-of-life care.Results: At 18 months, in a cohort of 100 patients, the use of cabazitaxel was estimated to result in 9 more patients achieving rPFS, 2 more patients achieving PFS, and 17 more survivors versus a second ARTA. The costs of SSEs, AEs, and end-of-life care were $498,909 (€424,073), $276,198 (€234,768), and $808,785 (€687,468), respectively, for cabazitaxel and $627,569 (€533,434), $251,124 (€213,455), and $1,028,294 (€874,050), respectively, for a second ARTA. Cabazitaxel was estimated to be associated with a 21% reduction in both SSE management and end-of-life care costs. Hospitalization cost was $1,442,870 (€1,226,440) for cabazitaxel and $1,728,394 (€1,469,135) for a second ARTA, representing an estimated 17% reduction in these costs. Cabazitaxel, as compared with a second ARTA, was associated with 58 fewer hospitalization days and 2 fewer ICU days and was estimated to avoid $323,095 (€274,630, 17%) in total costs, driven by SSEs management and end-of-life care.Conclusion: The use of cabazitaxel as a 3 L treatment after docetaxel and an ARTA in patients with mCRPC is estimated to result in clinical benefits (longer rPFS, PFS, and OS) and lower healthcare resource utilization (fewer hospitalization and ICU days), compared with a second ARTA. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis (OA) is common musculoskeletal disorders associated with overgeneration of free radicals, and it causes joint pain, inflammation, and cartilage degradation. Lignin as a natural antioxidant biopolymer has shown its great potential for biomedical applications. In this work, we developed a series of lignin-based nanofibers as antioxidative scaffolds for cartilage tissue engineering. Results: The nanofibers were engineered by grafting poly(lactic acid) (PLA) into lignin via ring-opening polymerization and followed by electrospinning. Varying the lignin content in the system was able to adjust the physiochemical properties of the resulting nanofibers, including fiber diameters, mechanical and viscoelastic properties, and antioxidant activity. In vitro study demonstrated that the PLA-lignin nanofibers could protect bone marrow-derived mesenchymal stem/stromal cells (BMSCs) from oxidative stress and promote the chondrogenic differentiation. Moreover, the animal study showed that the lignin nanofibers could promote cartilage regeneration and repair cartilage defects within 6 weeks of implantation. Conclusion: Our study indicated that lignin-based nanofibers could serve as an antioxidant tissue engineering scaffold and facilitate the cartilage regrowth for OA treatment. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) are considered a promising candidate in green energy storage due to their considerable abundance. The low mass loading (less than 2.0 mg cm−2) of SIBs‐based cathodes cannot meet the energy density on the practical device level, which is mainly restricted by sluggish Na+ transport. To the end, a facile and compatible strategy was demonstrated by utilizing hyaluronic acid (HA) binder to achieve fast ion transport and targeted energy density for Na3V2(PO4)3 (NVP) cathodes. As a novel functional aqueous binder, HA allowed cathodic materials to organize the unique conductive network. The network‐like electrode structure could buffer volume changes during sodiation/desodiation process and provide bi‐continuous charge transport channels for both Na+ and electrons at the interface. HA promoted the formation of the stable solid permeable interface films, protecting the electrochemical stability of the cathode and ensuring its good cycle performance. These functions of HA binder enabled that NVP delivered a reversible discharge capacity of 107.3 mAh g−1 at 0.5 C (1 C=117 mA g−1), which showed no sacrifice of electrochemical performances with mass loading increasing from 1.1 to 4.4 mg cm−2. Even at a high rate of 20 C, NVP‐HA (loading 4.0 mg cm−2) could reserve a good capacity of 76.8 mAh g−1 with the retention of 99.3 % after 2000 cycles. This study provides a novel strategy to achieve high energy density for SIBs in large‐scale energy storage. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction (ECR) is one of the most effective methods to obtain carbonaceous chemicals and reduce greenhouse gases passingly under the ambient condition. However, efficient electrocatalysts featured with high selectivity and stability are still lacking. A novel molecule-mediated Ag electrocatalyst with capped thiols is rationally designed for high-performance ECR. The thiol-capped and carbon-supported Ag nanostructures (Ag-TC) are formed by in situ electrochemical reduction from three-dimentional (3D) Ag-thiol metal-organic compound with cysteine as the anchor agent and carbon source. Ag-TC exhibits high selectivity and stability for CO2 conversion to CO (86.7%), which is more catalytically active than that of common Ag nanoparticles. The function of thiols for ECR is proved by replacing cysteine with alanine without thiol group. Meanwhile, alternatively replacing and removing the surface molecules on the Ag foil further demonstrate the effect of thiols. This work enlightens the promise of in situ construction method for molecule capped metal electrocatalyst towards selective and stable ECR. [ABSTRACT FROM AUTHOR]

Here, a sustainable antioxidant carrier based on lignin is developed to deliver palmitoyl tripeptide‐38. The poly(lignin/polyethylene glycol (PEG)/polypropylene glycol (PPG) urethane) is polymerized by randomly coupling lignin, PEG and PPG segment blocks using hexamethylene diisocyanate as a crosslinker. The derived poly(lignin/PEG/PPG urethane) loaded with palmitoyl tripeptide‐38, referred to as LM, is designed with careful considerations of both intrinsic and extrinsic causes of skin aging and a two‐way approach is taken on to effectively target the problem of skin aging. Upon exposure to the ultraviolet irradiation, LM successfully protects the cells by reducing the presence of reactive oxygen species, the damage to the antioxidant enzymes, and the expression of MMP‐1. Concurrently, LM also promotes the collagen production for skin repair. It is noteworthy that the collagen I content, in cells exposed to ultraviolet irradiation with LM‐4 and LM‐8 treatment (LM with 4 and 8 µg mL−1 palmitoyl tripeptide‐38, respectively), exceeds that of the control. Overall, this work successfully demonstrates a sustainable carrier with good antioxidant properties that effectively assisted the uptake of palmitoyl tripeptide‐38 by the cells. [ABSTRACT FROM AUTHOR]

As a top predator, the Eurasian otter (Lutra lutra) is an indicator of healthy freshwater ecosystems and a flagship species for conservation. Once widespread in China, the species is now distributed mainly in the upper reaches of the great rivers of western China. However, a lack of knowledge on local otter populations continues to hinder their conservation in China. Here, we conducted a detailed study on habitat use of Eurasian otters in Yushu City and Tangjiahe National Nature Reserve in western China using transect surveys. At both study sites, otters preferred to defecate on large rocks close to or protruding from the river and about 50 cm above the waterline. In Yushu, no spraints were found along the 5 km river bank section in the downtown area, with otters preferring sprainting sites with natural banks, riparian zones, and lower human population density. However, this pattern was not obvious at Tangjiahe, where river transformation and human disturbance are minor. Otter river use intensity was negatively correlated with elevation and human population density in Yushu in both seasons. In Tangjiahe, otter river use intensity was positively correlated with prey mass and flow rate and negatively correlated with human population in spring, but positively correlated with human population and negatively correlated with flow rate in autumn. These results reflect the flexible habitat use strategies of otters at different sites, underlining the necessity to study otters living in different regions and habitat types. We provide suggestions for river modification and call for more site-specific studies to promote otter conservation in China. [ABSTRACT FROM AUTHOR]

The cathode materials for sodium ion batteries (SIBs) are intrinsically unstable due to their oxidation by electrolyte solution at high voltage; thus, developing novel solid permeable interfaces as passivation layers is critical to avoid these side oxidation reactions and increase the cycling durability of SIBs. Nevertheless, the abuse of passivation layers can hinder the Na+ transfer and further impact the rate capability. Herein, we demonstrated an effective approach that utilized konjac glucomannan (KGM) biopolymer as a multifunctional binder to build stable solid permeable interface films to achieve high-performance for Na3V2(PO4)3/C (NVP) cathodes. Compared with polyvinylidene difluoride (PVDF), the strong adhesion and solid permeable interface films of KGM protect the integrity of the electrodes. The unique conductive network and rich polar functional groups enable KGM to enhance the transfer of electrons and Na+ ions at the interfaces. Thanks to the multiple functions of KGM offering adhesion strength, a conductive network and a solid permeable interface, the NVP cathode exhibited a reversible capacity of 108.0 mA h g−1 at 0.5C (1C = 117 mA g−1). At a high rate of 50C, NVP profited from KGM to show a good capacity of 63.1 mA h g−1 and a high durability of 10 000 cycles with a small fading rate of 0.00259% per cycle. Hard carbon‖NVP full batteries, using KGM as the cathode binder, possessed a high specific energy of 137.7 W h kg−1, indicating the potential applications of KGM as an environmentally friendly binder for achieving high-rate capacity and long-term cycling durability of SIBs. [ABSTRACT FROM AUTHOR]

Polyester elastomers are soft, biodegradable and biocompatible and are commonly used in various biomedical applications, especially in tissue engineering. These synthetic polyesters can be easily fabricated using various techniques such as solvent casting, particle leaching, molding, electrospinning, 3-dimensional printing, photolithography, microablation etc. A large proportion of tissue engineering research efforts have focused on the use of allografts, decellularized animal scaffolds or other biological materials as scaffolds, but they face the major concern of triggering immunological responses from the host, on top of other issues. This review paper will introduce the recent developments in elastomeric polyesters, their synthesis and fabrication techniques, as well as their application in the biomedical field, focusing primarily on tissue engineering in ophthalmology, cardiac and vascular systems. Some of the commercial and near-commercial polyesters used in these tissue engineering fields will also be described. [ABSTRACT FROM AUTHOR]

Porous and bulk water-responsive urethane-based shape memory polymers (SMPs) containing poly(ethylene glycol) (PEG), poly(caprolactone), and poly(dimethylsiloxane) are fabricated. The copolymers are processed by electrospinning to achieve porous structures. Shape fixation and recovery are achieved via the solvation and recrystallization of the hydrophilic PEG switching segment. Mechanical testing is performed to determine the SMP functionality. Water uptake rate for porous SMP is found to be higher than bulk SMP partly due to higher surface area for water contact. This enables porous structure water-responsive SMPs to recover faster compared to bulk SMPs. The water-responsive SMP exhibits good extents of shape fixity and shape recovery when immersed in water (≈35 °C). Different actuation times can be achieved based on the total surface area and efficiency of water-entry into the polymer. [ABSTRACT FROM AUTHOR]

Electronic devices have become ubiquitous in modern society and are prevalent in every facet of human activities. Although electronic devices have brought much convenience and value, the insatiable appetite for newer and more attractive devices has also created a growing ecological problem: managing electronic waste or e-waste. As the lifetime of electronic devices gets shorter and shorter, the pressure on e-waste management systems is mounting with no abate in sight. Therefore, an alternative to traditional electronics must be sought. Bio-degradable electronics have thus emerged as the most viable and ideal replacement to address the issue of uncontrollable e-waste. Bio-degradability will ensure that the waste generated will be at least non-toxic and even environmentally friendly. Furthermore, bio-degradable organic materials have also been shown to be biocompatible and human-friendly, being able to be metabolized safely in the body without causing adverse physiological reactions. As such, this developing class of “green” electronics is not only able to alleviate the growing e-waste problem, but also fulfils niche applications interfacing with the human body. This Review will introduce various bio-degradable organic materials that can serve as substitutes for the different components of an electronic device, highlight recent research achievements and applications in implementing such bio-degradable devices as well as present an overview of the printing technologies available that provide the low-cost and high throughput advantages of solution-processable organic materials over the traditional inorganic materials. [ABSTRACT FROM AUTHOR]

In light of the incessant consumption of raw materials in the world today, the search for sustainable resources is ever pressing. Lignin, the second most naturally abundant biomass, which makes up 15% to 35% of the cell walls of terrestrial plants, has always been treated as waste and used in low-value applications such as heat and electricity generation. However, its abundance in nature could potentially solve the problem of the rapidly depleting resources if it was successfully translated into a renewable resource or valorized to higher value materials. Advanced lignin modification chemistry has generated a number of functional lignin-based polymers, which integrate both the intrinsic features of lignin and additional properties of the grafted polymers. These modified lignin and its copolymers display better miscibility with other polymeric matrices, leading to improved performance for these lignin/polymer composites. This review summarizes the progress in using such biopolymers as reinforcement fillers, antioxidants, UV adsorbents, antimicrobial agents, carbon precursors and biomaterials for tissue engineering and gene therapy. Recent developments in lignin-based smart materials are discussed as well. [ABSTRACT FROM AUTHOR]

A lignin-based copolymer with good biocompability was successfully prepared via atom transfer radical polymerization (ATRP) for efficient gene delivery. Kraft lignin was modified into lignin-based macroinitiators and then poly(glycidyl methacrylate)-co-poly(ethylene glycol)methacrylate (PGMA–PEGMA) side chains were prepared via ATRP grafting onto lignin. Ethanolamine was sequentially functionalized onto lignin–PGMA–PEGMA and a cationic lignin–PGEA–PEGMA copolymer consisting of a lignin core and different-length PGEA–PEGMA side chains was produced. Lignin–PGEA–PEGMA copolymers could efficiently compact pDNA into nanoparticles with sizes ranging from 150 to 250 nm at N/P ratios of 10 or higher. The gene transfection efficiency depends greatly on the mass percentage of PGEA units and the N/P ratio. The lignin–PGEA–PEGMA with 46.9% (mass%) of PGEA units (i.e. LG100) has highest transfection efficiency in comparison with the copolymers with a lower amount of PGEA units. In addition, LG100 has high transfection efficiency under serum conditions, which is comparable to or much higher than PEI control in HEK 293T and Hep G2 cell lines. More importantly, lignin–PGEA–PEGMA copolymers have excellent antioxidant activity. The novel cationic lignin–PGEA–PEGMA copolymers can be promising gene carriers for gene delivery. [ABSTRACT FROM AUTHOR]

Lignin, one of the most abundant biopolymers on Earth, has been recognized as a renewable alternative to traditional petroleum-based plastics. The integration of lignin with synthetic and engineering plastics is an important approach to develop sustainable polymers. However, it is challenging to blend lignin with other polymers due to its brittle nature and poor dispersion in many composites. In order to improve the miscibility and compatibility of lignin with other plastics, a series of poly(methyl methacrylate) (PMMA) grafted lignin copolymers were prepared from atom transfer radical polymerization. The chain length of PMMA oligomers and glass transition temperature of the lignin copolymers was controlled by varying the lignin: methyl methacrylate ratio. The lignin mass fractions in the copolymers varied from 5.6% to 46.1%. These lignin–PMMA copolymers were further blended with poly(ε-caprolactone) (PCL) and engineered into nanofibrous composites by electrospinning. Tensile test and dynamical mechanical analysis showed that the incorporation of lignin–PMMA copolymers significantly improved the tensile strength, Young's modulus, and storage modulus of the resulting nanofibrous composites. The length of the PMMA chain played a crucial role in the miscibility of lignin in PCL, and therefore enhanced the stiffness and ultimate elongation of the resulting nanofibers. Cell culture studies suggested that these PCL/lignin–PMMA nanofibers were biocompatible and promoted the proliferation, attachment and interactions of human dermal fibroblasts. With reinforced mechanical properties and good biocompatibility, these green and stretchable electrospun nanofibers are potentially useful as biomaterial substrates for biomedical applications. [ABSTRACT FROM AUTHOR]

The dinuclear complex [Cu2I2(L1)2] ( 1) (L1=3-((4-(pyridin-2-yl)-1 H-1,2,3-triazol-1-yl)methyl)benzonitrile) is characterized by single-crystal X-ray diffraction (XRD), powder XRD, IR, photoluminescence spectroscopy, and thermogravimetric analysis. Unlike other related, known copper iodide complexes, it exhibits strong yellow emission in the solid state at both room temperature and 77 K. Showing good compatibility with PMMA, it is blended with the polymer in different weight ratios to prepare luminescent composite fibers. [ABSTRACT FROM AUTHOR]

Micro- and nanoengineering of materials offer novel technologies and serve as an interface between material sciences and biomedical nanotechnology. Various techniques are used for the engineering of polymers, and it allows the precise orientation of biomolecules with designed nanoregions in a substrate, with defined sizes and continuity offering well featured substrate topographies. Methods such as the electron beam lithography coupled with microcontact printing have been applied for the fabrication of high resolution surface features that are smaller than the size of a cell. This review elaborates more deeply on the different methods used for the fabrication of patterned surfaces such as the photolithography, electron beam lithography, microcontact printing, soft lithography, capillary force lithography, and patterning of electrospun fibers. The nanoengineered substrates may have the ability to influence the differentiation of stem cells to specific lineages and here we survey a few details on the influence of surface topology and its potential for tissue regeneration. [ABSTRACT FROM AUTHOR]

One funding number in the Acknowledgements section was unfortunately mistakenly used. This error did not affect any of the conclusions from the published paper. [ABSTRACT FROM AUTHOR]

The potential of pluripotent embryonic stem cells (ESCs) isolated from the inner mass of blastocysts are investigated for its ability to differentiate on biocompatible electrospun nanofibers, for regeneration of the myocardially infracted heart. Nanostructured poly( d, l-lactide- co-glycolide)/collagen (PLGA/Col) scaffolds with fiber diameters in the range of 300 ± 65 nm, was fabricated by electrospinning to mimic the extracellular matrix of the native tissue. During the culture of embryoid bodies outgrowth on the scaffolds, and further differentiation of ESCs to cardiomyocytes, the PLGA/Col nanofibers was found better than that of the electrospun PLGA nanofibers, where a better interaction and growth of ESC differentiated cardiomyocytes was observed on the composite scaffolds. The phenotypical characteristics of ESC-derived cardiomyocytes and molecular protein expression were carried out by scanning electron microscopy and immunocytochemistry, respectively. Our studies highlight the significance of a suitable material, its architecture, and cell-biomaterial interactions that is essential at a nanoscale level signifying the application of a bioengineered cardiac graft for stem cell differentiation and transplantation, which could be an intriguing strategy for cardiac regeneration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 447-454, 2014. [ABSTRACT FROM AUTHOR]

The potential of cardiomyogenic differentiation of human mesenchymal stem cells (hMSCs) on emulsion electrospun scaffold containing poly( l-lactic acid)-co-poly-(ε-caprolactone), gelatin and vascular endothelial growth factor (PLCL/GV) was investigated in this study. The characterizations of the scaffold were carried out using scanning electron microscope (SEM), transmission electron microscope, water contact angle and porometer. The proliferation of hMSCs showed that 73.4 % higher cell proliferation on PLCL/GV scaffolds than that on PLCL scaffold after 20 days of cell culture. Results of 5-chloromethylfluorescein diacetate staining and SEM morphology analysis indicated that hMSCs differentiated on PLCL/GV scaffolds showed irregular morphology of cardiomyocyte phenotype compared to the typical long and thin hMSC phenotype. Immunostaining results showed the expression of alpha actinin and myosin heavy chain. Our studies identified emulsion electrospinning as a method for fabrication of core-shell fibers suitable for the differentiation of stem cells to cardiac cells, with potential application in cardiac regeneration. [ABSTRACT FROM AUTHOR]

Myocardial infarction is the major cause of death in many industrialized nations as it leads to end-stage heart failure. Tissue engineering (TE) approaches for treatment of the infarcted tissue have gained huge attention over the recent years and research in this direction mainly aims for the optimization of a biomaterial scaffold with suitable cell source for tissue regeneration. In this regard, we fabricated completely natural polymeric scaffolds using fibrinogen and gelatin in two different weight ratios and performed cross-linking [Fib/Gel (1:4)-CL; Fib/Gel(2:3)-CL] while cross-linked fibrinogen scaffolds were used as the control. The fiber diameters of the fabricated scaffolds were obtained in the range of 150-300 nm. Chemical characterization of the scaffolds confirmed the presence of both the proteins and showed the absence of any chemical reactions between them. The tensile strength and the stiffness values of Fib/Gel(1:4)-CL matrices were found to be 0.0125 and 0.46 MPa, respectively, which were much similar to the innate properties of the native myocardium. Cell culture studies using human cardiomyocytes revealed higher cell prolifer-ation on Fib/Gel(1:4)-CL scaffolds compared to cell proliferation on Fib/Gel(2:3)-CL scaffolds, which was even higher than the cell proliferation on cross-linked fibrinogen scaf-folds. Moreover, the cardiomyocytes seeded on composite substrates expressed the typical functional cardiac proteins such as alpha-actinin, troponin I, connexin-43, and myosin heavy chain, and could be potential for application in cardiac TE. [ABSTRACT FROM AUTHOR]

Nanotechnology has enabled the engineering of a variety of materials to meet the current challenges and needs in vascular tissue regeneration. In this study, four different kinds of native proteins namely collagen, gelatin, fibrinogen, and bovine serum albumin were incorporated with polyurethane (PU) and electropsun to obtain composite PU/protein nanofibers. SEM studies showed that the fiber diameters of PU/protein scaffolds ranged from 245 to 273 nm, mimicking the nanoscale dimensions of native ECM. Human aortic smooth muscle cells (SMCs) were cultured on the electrospun nanofibers, and the ability of the cells to proliferate on different scaffolds was evaluated via a cell proliferation assay. Cell proliferation on PU/Coll nanofibers was found the highest compared to other electrospun scaffolds and it was 42 % higher than the proliferation on PU/Fib nanofibers after 12 days of cell culture. The cell-biomaterial interaction studies by SEM confirmed that SMCs adhered to PU/Coll and PU/Gel nanofibers, with high cell substrate coverage, and both the scaffolds promoted cell alignment. The functionality of the cells was further demonstrated by immunocytochemical analysis, where the SMCs on PU/Coll and PU/Gel nanofibers expressed higher density of SMC proteins such as alpha smooth muscle actin and smooth muscle myosin heavy chain. Cells expressed biological markers of SMCs including aligned spindle-like morphology on both PU/Coll and PU/Gel with actin filament organizations, better than PU/Fib and PU/BSA scaffolds. Our studies demonstrate the potential of randomly oriented elastomeric composite scaffolds for engineering of vascular tissues causing cell alignment. [ABSTRACT FROM AUTHOR]

Poly(3-hexylthiophene) (P3HT) is one of the most promising photovoltaic (PV) polymers in photocurrent therapy. A novel photosensitive scaffold for skin tissue engineering was fabricated by blending P3HT with polycaprolactone (PCL) and electrospun to obtain composite PCL/P3HT nanofibers with three different weight ratios of PCL : P3HT (w/w) of 150 : 2 [PCL/P3HT(2)], 150 : 10 [PCL/P3HT(10)] and 150 : 20 [PCL/P3HT(20)]. The photosensitive properties of the blend solutions and the composite nanofibers of PCL/P3HT were investigated. The incident photon-to-electron conversion efficiencies of the PCL/P3HT(2), PCL/P3HT(10), PCL/P3HT(20) were identified as 2.0 × 10−6, 1.6 × 10−5 and 2.9 × 10−5, respectively, which confirm the photosensitive ability of the P3HT-containing scaffolds. The biocompatibility of the scaffold was evaluated by culturing human dermal fibroblasts and the results showed that the proliferation of HDFs under light stimulation on PCL/P3HT(10) was 12.8%, 11.9%, and 11.6% (p≤ 0.05) higher than the cell growth on PCL, PCL/P3HT(2) and PCL/P3HT(20), respectively. Human dermal fibroblasts cultured under light stimulation on PCL/P3HT(10) not only showed better cell proliferation but also retained cell morphology similar to the phenotype observed on tissue culture plates (control). Our experimental results suggest novel and potential application of an optimized amount of P3HT-containing scaffold, especially PCL/P3HT(10) nanofibrous scaffold in photocurrent therapy for skin regeneration. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) and silver ions (Ag+) show growth-inhibitory activity against microorganisms and have been used for decades as antibacterial agents in various fields. To fabricate a nanofibrous scaffold which is antibacterial against bacteria and non-toxic to cells, we electrospun composite poly(L-lactic acid)-co-poly(ϵ-caprolactone) nanofibres containing silver nanoparticles (PLLCL-AgNPs) with different concentrations (0.25, 0.50 and 0.75 wt%) of silver nitrate (AgNO3) in PLLCL. The diameters of the electrospun PLLCL-AgNPs nanofibres decreased with the increase of AgNO3 concentration in PLLCL solutions. Human skin fibroblasts cultured on the scaffolds showed that the PLLCL nanofibres containing lesser amounts of AgNPs (0.25 wt%) had better cell proliferation and retained the cell morphology similar to the phenotype observed on tissue culture plates (control). The antibacterial activity of AgNPs in PLLCL nanofibres was investigated against Staphylococcus aureus and Salmonella enterica and the antimicrobial activity was found to increase with the increasing concentration of nanoparticles present in the scaffold. Based on our studies, we propose that PLLCL nanofibres containing 0.25 wt% AgNO3 or PLLCL-Ag(25), favors cell proliferation and inhibits bacteria and could be a suitable substrate for wound healing. [ABSTRACT FROM AUTHOR]

A biocompatible and elastomeric nanofibrous scaffold is electrospun from a blend of poly(1,8-octanediol- co-citrate) [POC] and poly( L-lactic acid) - co-poly-(3-caprolactone) [PLCL] for application as a bioengineered patch for cardiac tissue engineering. The characterization of the scaffolds was carried out by Fourier transform infra red spectroscopy, scanning electron microscopy (SEM), and tensile measurement. The mechanical properties of the scaffolds are studied with regard to the percentage of POC incorporated with PLCL and the results of the study showed that the mechanical property and degradation behavior of the composites can be tuned with respect to the concentration of POC blended with PLCL. The composite scaffolds with POC: PLCL weight ratio of 40:60 [POC/PLCL4060] was found to have a tensile strength of 1.04 ± 0.11 MPa and Young's Modulus of 0.51 ± 0.10 MPa, comparable to the native cardiac tissue. The proliferation of cardiac myoblast cells on the electrospun POC/PLCL scaffolds was found to increase from Days 2 to 8, with the increasing concentration of POC in the composite. The morphology and cytoskeletal observation of the cells also demonstrated the biocompatibility of the POC containing scaffolds. Electrospun POC/PLCL4060 nanofibers are promising elastomeric substrates that might provide the necessary mechanical cues to cardiac muscle cells for regeneration of the heart. © 2012 Wiley Periodicals, Inc. Biopolymers 97:529-538, 2012. [ABSTRACT FROM AUTHOR]

Emulsion electrospinning is a novel approach to fabricate core-shell nanofibers, and it is associated with several advantages such as the alleviation of initial burst release of drugs and it protects the bioactivity of incorporated drugs or proteins. Aiming to develop a sustained release scaffold which could be a promising substrate for cardiovascular tissue regeneration, we encapsulated vascular endothelial growth factor (VEGF) with either of the protective agents, dextran or bovine serum albumin (BSA) into the core of poly( l-lactic acid- co-ε-caprolactone) (PLCL) nanofibers by emulsion electrospinning. The morphologies and fiber diameters of the emulsion electrospun scaffolds were determined by scanning electron microscope, and the core-shell structure was evaluated by laser scanning confocal microscope. Uniform nanofibers of PLCL, PLCL-VEGF-BSA, and PLCL-VEGF-DEX with fiber diameters in the range of 572 ± 92, 460 ± 63, and 412 ± 61 nm, respectively were obtained by emulsion spinning. The release profile of VEGF in phosphate-buffered saline for up to 672 h (28 days) was evaluated, and the scaffold functionality was established by performing cell proliferations using human bone marrow derived mesenchymal stem cells. Results of our study demonstrated that the emulsion electrospun VEGF containing core-shell structured PLCL nanofibers offered controlled release of VEGF through the emulsion electrospun core-shell structured nanofibers and could be potential substrates for cardiac tissue regeneration. [ABSTRACT FROM AUTHOR]

Hydrogel-based biomaterial systems have great potential for tissue reconstruction by serving as temporary scaffolds and cell delivery vehicles for tissue engineering (TE). Hydrogels have poor mechanical properties and their rapid degradation limits the development and application of hydrogels in TE. In this study, nanofiber reinforced composite hydrogels were fabricated by incorporating electrospun poly(&egr;-caprolactone) (PCL)/gelatin 'blend' or 'coaxial' nanofibers into gelatin hydrogels. The morphological, mechanical, swelling and biodegradation properties of the nanocomposite hydrogels were evaluated and the results indicated that the moduli and compressive strengths of the nanofiber reinforced hydrogels were remarkably higher than those of pure gelatin hydrogels. By increasing the amount of incorporated nanofibers into the hydrogel, the Young's modulus of the composite hydrogels increased from 3.29 ± 1.02 kPa to 20.30 ± 1.79 kPa, while the strain at break decreased from 66.0 ± 1.1% to 52.0 ± 3.0%. Compared to composite hydrogels with coaxial nanofibers, those with blend nanofibers showed higher compressive strength and strain at break, but with lower modulus and energy dissipation properties. Biocompatibility evaluations of the nanofiber reinforced hydrogels were carried out using bone marrow mesenchymal stem cells (BM-MSCs) by cell proliferation assay and immunostaining analysis. The nanocomposite hydrogel with 25 mg ml-1 PCL/gelatin 'blend' nanofibers (PGB25) was found to enhance cell proliferation, indicating that the 'nanocomposite hydrogels' might provide the necessary mechanical support and could be promising cell delivery systems for tissue regeneration. [ABSTRACT FROM AUTHOR]