Search

The employment of individual poly(lactic acid) (PLA) or cellulose acetate (CA) electrospun fibers as bone tissue replacement was restricted by the weak mechanical properties of CA and the poor cell-affinity of PLA. In this study, core-shell fibers with PLA as the core component and CA as the shell layer were fabricated via coaxial electrospinning with significant improvements in the tensile strength and biocompatibility in comparison to individual PLA and CA fibers and blend PLA/CA fibers. The employment of a core-to-shell flow rate ratio of 0.25:0.5 mL/hr:mL/hr resulted in the formation of defect-free and uniformly distributed PLA-CA core-shell fibers (cs-PLA1-CA2) with the highest ultimate tensile strength (19.53 ± 1.68 MPa) and Young's modulus (0.62 ± 0.09 GPa) among all core-shell fibers produced in this study. These tensile values match the tensile properties of native cancellous bone and represent around a 130% and 160% improvement in strength and stiffness compared to monolithic CA fibers, respectively. Higher weight fraction and improved crystallinity of PLA-core were revealed to contribute to this mechanical enhancement of cs-PLA1-CA2. An in vitro biocompatibility study was conducted using human fetal osteoblasts (hFOB). The results indicate improved cell distribution, better cell-scaffold attachment, and higher cell proliferation and alkaline phosphatase (ALP) activity of cs-PLA1-CA2 compared to monolithic PLA and blend PLA/CA fibers, while matching the growth performance of hFOB seeded on tissue culture polystyrene (TCP). The PLA-CA core-shell fibers produced in this study hold great promise for use as bone tissue scaffolds. [ABSTRACT FROM AUTHOR]

Aims: An intriguing difference between vertebrate skeletal and cardiac muscles is that the lengths of the thin filaments are constant in the former but variable in the latter. The thick filaments have constant lengths in both types of muscles. The contractile behaviour of a muscle is affected by the lengths of both types of filaments as the tension generated during contraction depends on the amount of filament overlap. To understand the behaviour of cardiac muscle, it is important to know the distribution of the thin filament lengths. The previous detailed analysis by Robinson and Winegrad used serial transverse sections to determine the lengths of the thin filaments. However, the precision, set by the 100 nm section thickness, was low. Here, we have used electron tomography to produce 3D images of rat and mouse cardiac muscles in which we can actually see individual thin filaments up to the free ends and see that these free ends have variable locations. For comparison, we also measure the thin filament lengths in skeletal muscle (frog sartorius). [ABSTRACT FROM PUBLISHER]

In this study, modified coaxial electrospinning (CE) was employed to improve electrospinnability and to tailor surface morphology and bead formation of poly(lactic acid) (PLA) fibers by means of core-to-shell flowrate ratio variation. Chloroform/N,N-dimethylformamide (DMF) mixture was used as sheath solution which serves as a protective layer to prevent rapid solidification of PLA droplet causing needle clogging. Five different core-to-shell flowrate ratios yielded beads-on-a-string PLA fibers with distinctive fiber and bead properties. These diverse morphologies were characterized in terms of fiber diameter (D f), fiber percentage (P f), number of beads per area (n b), bead area (A b), bead aspect ratio (L b /D b), ratio of bead-to-fiber diameter (D b /D f) and surface roughness. From thermal analysis, crystallinity of PLA fibers was shown to be significantly dependent on the fiber processing history, where higher degree of molecular chain orientation and longer jet flight time correspond to higher crystallinity values. Core-to-shell flowrate ratio of 1:3 resulted in PLA fibers with the least n b , smallest D b /D f and highest L b /D b (spindle-like shape), which correspond to the highest tensile properties and minimum hydrophobicity among beads-on-a-string fibers studied, as indicated by effective stress-strain curve and water contact angle measurement. Furthermore, the results suggested that D b /D f was the dominant factor affecting tensile properties more than the effect of crystallinity, while L b /D b (bead shape) was the key aspect which influenced the wettability of the PLA beads-on-a-string fibers. [Display omitted] • Clogging was eliminated through employment of modified coaxial electrospinning. • Core-to-shell flowrate ratio variation yielded distinctive fiber/bead properties. • Tensile properties were predominantly affected by bead-to-fiber diameter ratio. • Bead aspect ratio primarily influencing the wettability of beads-on-a-string fibers. [ABSTRACT FROM AUTHOR]

Reusable and eco-friendly poly(vinyl alcohol)/chitin/nanocellulose based biopolymer composite films were synthesized and characterized. Maleic acid (MA) was used as a crosslinker of the biopolymer composite film. The effect of constituent materials of the biopolymer composite film and the pH on removal of methylene blue (MB) dye from aqueous testing solution were studied by batch adsorption studies. The successful deposition of MB dye onto the adsorbent (biopolymer composite film) was confirmed using Fourier transform infrared spectroscopy (FTIR) analysis. Adsorption isotherm studies were fitted to the Freundlich model with the maximum adsorption capacity amounted to 467.5 mg/g. The adsorption kinetics were in conformance to the pseudo-second order model (R2 = 0.9924–0.9987). The point zero charge (pHpzc) of the adsorbents were investigated by pH drift method where the MA cross-linked adsorbents showed pHpzc values in the range of 8.05–8.55. Moreover, the best adsorption performance was observed in sample PVA/CT10/NCC/MA30, with calculated maximum adsorption capacity amounted to 467.5 mg/g. Thermodynamic studies showed that the adsorption were spontaneous, exothermic and less-ordered reactions. High adsorption reusability was determined for PVA/CT10/NCC/MA30 composite, with adsorption percentage of 83.67 ± 1.08% at the fifth cycle. All these positive results implied the potential application of PVA/Chitin/NCC composites for the MB dye's adsorption from aqueous testing solution. [ABSTRACT FROM AUTHOR]

The growth of global food demand combined with the increased appeal to access different foods from every corner of the globe is forcing the food industry to look for alternative technologies to increase the shelf life. Essential oils (EOs) as naturally occurring functional ingredients have shown great prospects in active food packaging. EOs can inhibit the growth of superficial food pathogens, modify nutritious values without affecting the sensory qualities of food, and prolong the shelf life when used in food packaging as an active ingredient. Since 2016, various reports have demonstrated that combinations of electrospun fibers and encapsulated EOs could offer promising results when used as food packaging. Such electrospun platforms have encapsulated either pure EOs or their complexation with other antibacterial agents to prolong the shelf life of food products through sustained release of active ingredients. This paper presents a comprehensive review of the essential oil-loaded electrospun fibers that have been applied as active food packaging material. [ABSTRACT FROM AUTHOR]

Organ repair, regeneration, and transplantation are constantly in demand due to various acute, chronic, congenital, and infectious diseases. Apart from traditional remedies, tissue engineering (TE) is among the most effective methods for the repair of damaged tissues via merging the cells, growth factors, and scaffolds. With regards to TE scaffold fabrication technology, polyurethane (PU), a high-performance medical grade synthetic polymer and bioactive material has gained significant attention. PU possesses exclusive biocompatibility, biodegradability, and modifiable chemical, mechanical and thermal properties, owing to its unique structure-properties relationship. During the past few decades, PU TE scaffold bioactive properties have been incorporated or enhanced with biodegradable, electroactive, surface-functionalised, ayurvedic products, ceramics, glass, growth factors, metals, and natural polymers, resulting in the formation of modified polyurethanes (MPUs). This review focuses on the recent advances of PU/MPU scaffolds, especially on the biomedical applications in soft and hard tissue engineering and regenerative medicine. The scientific issues with regards to the PU/MPU scaffolds, such as biodegradation, electroactivity, surface functionalisation, and incorporation of active moieties are also highlighted along with some suggestions for future work. Various polyurethane (PU) and modified polyurethane (MPU) tissue engineering scaffolds (TES). Unlabelled Image [ABSTRACT FROM AUTHOR]

The key attributes of core–shell fibers are their ability to preserve bioactivity of incorporated-sensitive biomolecules (such as drug, protein, and growth factor) and subsequently control biomolecule release to the targeted microenvironments to achieve therapeutic effects. Such qualities are highly favorable for tissue engineering and drug delivery, and these features are not able to be offered by monolithic fibers. In this review, we begin with an overview on design requirement of core–shell fibers, followed by the summary of recent preparation methods of core–shell fibers, with focus on electrospinning-based techniques and other newly discovered fabrication approaches. We then highlight the importance and roles of core–shell fibers in tissue engineering and drug delivery, accompanied by thorough discussion on controllable release strategies of the incorporated bioactive molecules from the fibers. Ultimately, we touch on core–shell fibers-related challenges and offer perspectives on their future direction towards clinical applications. [ABSTRACT FROM AUTHOR]

Electrospun polycaprolactone (PCL) nanofibers have emerged as a promising material in diverse biomedical applications due to their various favorable features. However, their application in the field of biosensors such as point-of-care lateral flow assays (LFA) has not been investigated. The present study demonstrates the use of electrospun PCL nanofibers as a reaction membrane for LFA. Electrospun PCL nanofibers were treated with NaOH solution for different concentrations and durations to achieve a desirable flow rate and optimum detection sensitivity in nucleic acid-based LFA. It was observed that the concentration of NaOH does not affect the physical properties of nanofibers, including average fiber diameter, average pore size and porosity. However, interestingly, a significant reduction of the water contact angle was observed due to the generation of hydroxyl and carboxyl groups on the nanofibers, which increased their hydrophilicity. The optimally treated nanofibers were able to detect synthetic Zika viral DNA (as a model analyte) sensitively with a detection limit of 0.5 nM. Collectively, the benefits such as low-cost of fabrication, ease of modification, porous nanofibrous structures and tunability of flow rate make PCL nanofibers a versatile alternative to nitrocellulose membrane in LFA applications. This material offers tremendous potential for a broad range of point-of-care applications. [ABSTRACT FROM AUTHOR]