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This paper investigates delivery of encapsulated drug from poly lactic-co-glycolic micro-/nano-particles. Experimental data collected from about 50 papers are analyzed by machine learning algorithms including linear regression, principal component analysis, Gaussian process regression, and artificial neural networks. The focus is to understand the effect of drug solubility, drug molecular weight, particle size, and pH-value of the release matrix/environment on drug release profiles. The results obtained from machine learning is then used as guidelines for designing new in vitro experiments to examine dependence of drug release profiles on those four factors. It is interesting to see that indeed the results of the new in vitro experiments are in basic agreement with the results obtained from machine learning. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) was modified using D‐mannitol (DM) and 1‐butyl‐3‐methylimidazole bromide (BMIMBr) as the complex plasticizer (DB), and PVA/DB composite was prepared. The plasticizing effect of DB on PVA was studied by Fourier transform infrared spectroscopy (FT‐IR), differntial scanning calorimetry (DSC), thermos gravimetric analysis (TGA) and melt flow indexer (MI). FT‐IR analysis indicated that Br− of BMIMBr and OH of DM could form H‐bonds with OH of PVA. With the increase of DB, the melt temperature (Tm2) and crystallization temperature (Tc1) of PVA/DB composite decreased, the initial thermal decomposition temperatures (Td), thermal processing window (ΔT) and MI values increased respectively. Based on above studies, the influence of DB content on rheological properties of PVA/DB composite was investigated by the capillary rheometer. The result displayed that apparent viscosity of PVA/DB composite decreased with increasing DB content, shear rate and measured temperature. The non‐Newtonian index (n) increased and structural viscosity index (Δη) decreased with the increase of measured temperature and DB. The viscous flow activation energy (Eη) decreased as the shear rate and DB content increased. When the measured temperature, DB content and shear rate were in the range of Tm2+30 −Tm2+35 °C, 40–50 wt% and 764.8–1504.9 s−1, respectively, the spinnability of PVA/DB composite was optimal, which will lay a theoretical foundation for the exploration of melt spinning process in the future. [ABSTRACT FROM AUTHOR]

The development of wound-dressing materials has attracted significant research interests in recent years. With the advancement of nanofabrication, the application of nanoparticles (NPs) in drug delivery systems has become feasible. However, most existing work focuses on incorporation of metal, metal/semi-metal oxide, or organic particles into nanofiber scaffolds. There has been a lack of work on the incorporation of drug-encapsulated polymeric particles into nanofiber scaffolds. In this study, gentamicin-encapsulated poly-(lactic-co-glycolic acid) (PLGA) NPs were synthesized via a double emulsion solvent evaporation method. Electrospinning was used to incorporate gentamicin-encapsulated PLGA NPs into nanofiber scaffolds. Atomic force microscopy (AFM), dynamic light scattering, scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV–vis), and an agar diffusion method were utilized to characterize the morphologies, release profiles, and antibacterial activities of various gentamicin-loaded PLGA NP-incorporated nanofiber scaffolds. The results indicated that the PLGA NPs had a spherical morphology with an average diameter of 130 nm. Purification of PLGA NPs was essential to eliminate the residual poly-(vinyl alcohol) (PVA) and to prevent particle agglomeration. The purified PLGA NPs were uniformly and individually incorporated into the polyurethane (PU)/ poly-(ethenyl oxide) (PEO) or PEO-only nanofiber scaffolds but nearly none into the PU-only fiber scaffolds. PEO served as a continuous phase in the PU/PEO mixture, which significantly improved the compatibility of PLGA NPs and PU, resulting in a well-dispersed distribution of PLGA NPs in the monolithic nanofiber scaffolds. Excellent antibacterial properties against Escherichia coli were found in both PU/PEO and PEO nanofiber scaffolds. This study of incorporating gentamicin-encapsulated PLGA NPs into fiber scaffolds provides insights for achieving successful incorporation of drug-encapsulated polymeric NPs into fiber scaffolds. This offers a promising microfabrication technology for delivery of therapeutic molecules with controlled release for biomedical applications. [ABSTRACT FROM AUTHOR]

Different vinyl acetate (VAc) and vinyl benzoate (VBz) monomer ratios have been chosen as monomers to create high polymerization degree (Pn) and high syndiotacticity‐diad content (S‐diad) poly(vinyl alcohol) (PVA) polymers via emulsifier‐free polymerization in order to address the problem of limited mechanical capabilities of PVA fibers prepared with low Pn and low S‐diad polymer. The variations in hydrogen bonding, Pn, S‐diad, and viscosity of different PVA polymers were investigated and evaluated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, and a viscosity tester. Moreover, various PVA fibers with high strength and modulus have been manufactured using a synthetic polymer as the raw material for dry‐wet spinning. The effect of Pn and S‐diad on the mechanical and thermal characteristics of PVA fibers is evaluated using a variety of characterization techniques, such as the scanning electron microscope, differential scanning calorimetry, thermogravimetric analyzer, X‐ray diffraction, and tensile tester. As the ratio of VBz monomer increased, the results suggested that VBz may have a considerable impact on the Pn and S‐diad of PVA polymers, the OH vibration absorption peak reduced from 3491 to 3442 cm−1; the Pn increased from 2112 to 17,704; and the S‐diad rose from 51.2% to 60.1%. In addition to the fact that Pn and S‐diad significantly increased the fibers' strength and modulus, the crystallinity increased from 41.8% to 51.7%, and the orientation degree rose from 87.5% to 91.7%, as Pn and S‐diad increased; the tensile strength and highest elastic modulus increased from 9.71 ± 0.3 cN/dtex to 12.74 ± 0.5 cN/dtex (increased of 31.2%) and 264.52 ± 9.3 cN/dtex to 338.41 ± 8.6 cN/dtex (increased of 27.9%); the elongation at break decreased from 5.63 ± 0.3% to 2.92 ± 0.2%. [ABSTRACT FROM AUTHOR]

PVA/IL composites were successfully prepared with an ionic liquid (IL), 1‐butyl‐3‐methylimidazolium bromide and poly(vinyl alcohol) (PVA). The plasticizing effect of IL on PVA was investigated using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and melt flow index (MI) measurements. FTIR analysis indicated that the anion (Br−) of IL could form hydrogen bonds with the hydroxyl groups of PVA. With an increase of IL, –OH absorption peaks of PVA/IL composites shifted to higher wavenumbers. DSC analysis showed that both melt and crystallization temperatures of the PVA/IL composites decreased as IL content increased. XRD analysis showed that the degree of crystallinity of the PVA/IL composites had a decreasing trend with an increase of IL. TGA showed that IL could effectively improve the thermal stability of PVA. The thermal stability of the PVA/IL composites decreased gradually with increasing IL content, but was higher than that of PVA. Thermal processing window (ΔT) analysis indicated that the addition of IL could significantly broaden ΔT of the PVA/IL composites, and their ΔT values first remained basically unchanged and then increased slightly with an increase of IL. In addition, MI analysis presented that the melt processability of the PVA/IL composites was not improved with the addition of IL and it was gradually improved with increasing IL content. In this work, PVA/IL composites with wide ΔT and high melt flow properties were prepared, which will lay a solid foundation for the preparation of high‐performance PVA fibers by melt spinning. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

In this study, we investigated engineered nanoparticle (ENP) release associated with the contamination of personal protective clothing during the simulated motion of the human wearing the ENP-contaminated protective clothing and evaluated the relative ENP retention on the fabric. The release of airborne ENPs can contribute to inhalation exposure, which is the route of exposure of most concern to cause adverse health effects in the pulmonary system. The evaluation focuses on four popular fabric materials making the laboratory coats (cotton, polypropylene, polyester cotton blend, and Tyvek) and three types of ENPs (Al2O3, carbon black (CB), and carbon nanotube (CNT)). The magnitudes of particle contamination and resuspension were investigated by measuring the number concentration increase of airborne particles in sizes of 10 nm to 10 μm and the weight changes on fabric pieces. Collected aerosol particles and contaminated fabric surfaces were further characterized for understanding particle morphology, elements, agglomeration, and surface contamination status. The particle resuspension from the contaminated lab coat fabric was found to vary by the type of fabric material. Cotton fabric showed the highest level of particle resuspension for all three tested ENPs. Data were evaluated to determine the dominant forces responsible for ENP adhesion on the surface of the fabric. Tyvek fabric was determined as the best fabric for trapping Al2O3 and carbon black ENPs, indicating less resuspension of particles, meaning lower subsequent release, but not durable enough to wear for the long term compared with other fabrics. [ABSTRACT FROM AUTHOR]

To improve the mechanical properties of polyvinyl alcohol (PVA) fibers, a series of PVA fibers were prepared via dry‐wet spinning with cross‐linking of boric acid (BA) (PVA/BA fibers), and using the mixed solvent of dimethyl sulfoxide and water. Moreover, the final PVA/BA fibers were characterized by Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), differential scanning calorimetery (DSC), thermogravimetric analyzer (TGA), powder X‐ray diffraction (XRD) and yarn strength tester. Furthermore, with the increasing of BA content, FTIR analysis showed that the degree of crosslinking of BA with PVA increased. SEM images of final PVA/BA fibers presented smooth surfaces, and the diameters decreased firstly and then increased. DSC, TGA, and XRD analysis indicated that the melting temperatures, thermal properties and crystallinities first increased and then decreased with the increasing of BA content. In addition, mechanical properties measurements illustrated that the cross‐linking existed at an optimal BA content of 0.3 wt%, and PVA/BA‐0.3 fiber had the highest tensile strength and Young's modulus of 13.1 ± 0.4 and 360.2 ± 10.4 cN/dtex, respectively. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) fibers were prepared using PVA with different degree of polymerization (DP) under the same wet spinning process. The effect of the DP of PVA on the structures and properties of PVA and PVA fibers were studied by using nuclear magnetic resonance hydrogen spectroscopy (1H‐NMR), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimeter (DSC), thermo gravimetric analysis (TGA), and environmental scanning electron microscope (ESEM). The results showed that DP had little effect on the crystallinity and tacticity of PVA, but had a positive effect on melting temperature, and initial decomposition temperature of PVAs. The hot drawing ratio determined by the spinning process where the PVA fibers could be continuously collected without breaking. The drawing ratio was decreased with an increase of DP, resulting in an increase of the final fiber diameter. The PVA fibers with medium DP and medium size demonstrated high strength and high modulus, but relatively low breaking elongation. It suggested that high DP of PVA was not a guarantee of high strength and high modulus PVA fibers, but rather a primary structure factor. The fiber performance was determined by a comprehensive effect combining a variety of factors including polymer properties and spinning conditions. It provided a guideline for PVA fiber manufacture that the PVAs with different DP require different spinning processes to obtain optimal fiber performance. [ABSTRACT FROM AUTHOR]

Biomaterials to facilitate the restoration of cardiac tissue is of emerging importance. While there are many aspects to consider in the design of biomaterials, mechanical properties can be of particular importance in this dynamically remodeling tissue. This review focuses on one specific processing method, electrospinning, that is employed to generate materials with a fibrous microstructure that can be combined with material properties to achieve the desired mechanical behavior. Current methods used to fabricate mechanically relevant micro-/nanofibrous scaffolds, in vivo studies using these scaffolds as therapeutics, and common techniques to characterize the mechanical properties of the scaffolds are covered. We also discuss the discrepancies in the reported elastic modulus for physiological and pathological myocardium in the literature, as well as the emerging area of in vitro mechanobiology studies to investigate the mechanical regulation in cardiac tissue engineering. Lastly, future perspectives and recommendations are offered in order to enhance the understanding of cardiac mechanobiology and foster therapeutic development in myocardial regenerative medicine. [ABSTRACT FROM AUTHOR]

ABSTRACT: Hyperbranched polymers have been found effective in controlling the dispersibility of carbon nanotubes in aqueous solutions. In this study, hyperbranched polylysine (HBPL) was synthesized using lysine and N,N′‐methylenebisacrylamide as precursors via Michael addition. The HBPL then was used to noncovalently modify multiwalled carbon nanotubes (MWCNTs) to prepare MWCNTs‐HBPL. The obtained MWCNTs‐HBPL composites were characterized using FTIR spectroscopy, Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The results showed that the HBPL was successfully attached to the surface of MWCNTs via noncovalent interactions. The dispersibility of the MWCNTs‐HBPL composites in aqueous solutions was investigated using digital photographs, ultraviolet–visible absorption spectroscopy, and zeta potential measurements. The results demonstrated that both the mass ratio of MWCNT to HBPL and the pH of the solution had a significant impact on the dispersibility of the MWCNTs/HBPL solution, suggesting that HBPL treatment is an effective method of controlling the dispersibility of MWCNTs in aqueous solutions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46249. [ABSTRACT FROM AUTHOR]

Persimmon dye is a natural dye potentially used to promote sustainable textile industry. In this article, cotton and wool fabrics were dyed with persimmon dye. The performance of the dye was characterized using color strength and appearance analysis (ColorQuest), American Association of Textile Chemists and Colorists colorfastness tests, and Fourier transform infrared spectroscopy (FTIR). The results showed color strength of dyed cotton and wool fabrics was enhanced with increasing dye concentration and dyeing times. The comparison between cotton and wool suggested persimmon dye exhibits better dyeing performance (higher color strength and higher colorfastness ratings) on wool fabrics than on cotton fabrics. The FTIR analysis indicated no significant chemical reactions or changes in persimmon dye occurred to dyed fabrics, suggesting negligible impact on chemical and physical properties of the dyed fabrics. The reported results are valuable in exploring the opportunity of using persimmon dye as a useful natural dye for a sustainable textile dyeing industry, especially in the case of dyeing natural fibers. [ABSTRACT FROM AUTHOR]

10,12‐Pentacosadiynoic acid (PCDA) monomers were mixed with polyurethane (PU) or poly(ethylene oxide) (PEO) and the mixtures were electrospun to obtain composite nanofibers that were then photopolymerized via ultraviolet radiation, resulting polydiacetylene (PDA) in the nanofibers. The PDA demonstrated color‐changing properties in the presence of Escherichia coli, which exhibited potential for developing flexible colorimetric biosensors for medical textiles. Phase separation was found in the PEO–PDA fibers, resulting in amorphous PEO accumulation at the fiber surface. In contrast, the PU–PDA fibers demonstrated a homogeneous microstructure throughout the fibers. Tensile test results suggested a molecular orientation in the PU–PDA fibers that significantly improved the mechanical properties of the fibers. The presence of PDA in the matrix polymer reduced the overall strength and breaking elongation of both composite nanofibers in comparison to 100% PEO and PU fibers. A single PU–PDA fiber showed significantly higher stiffness and modulus than a single PEO–PDA fiber. Force–distance curve analysis suggested that the PU–PDA fibers exhibited an elastic deformation. In a comparison, the PEO–PDA fibers were brittle and showed low modulus. The results of structural and mechanical properties suggest that the PU–PDA nanofibers are a promising composite for developing nonadherent, durable, and flexible colorimetric biosensors used in medical textiles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47877. [ABSTRACT FROM AUTHOR]

In recent years, Janus materials have become a research hotspot in the field of materials science; however, fabricating inorganic Janus-like nanofibers (NFs) is still a challenge. Herein, we report novel ZnO/NiO Janus-like NFs with efficient photocatalytic performance via an electrospinning method followed by calcination treatment. The morphology, structure, chemical composition and crystallinity of ZnO/NiO Janus-like NFs were studied in detail via SEM, TEM, HRTEM, EDS, FT-IR, XPS and XRD, indicating that the NFs had a perfect Janus-like structure composed of ZnO and NiO. A series of photocatalytic experiments were carried out in aqueous organic dye solutions under 365 nm UV radiation for 1 h, with the degradation rate of malachite green able to reach 96%, proving that the NFs have great potential in the field of organic dye degradation. Furthermore, a reasonable catalytic mechanism for the ZnO/NiO Janus-like NFs was proposed, which was discussed from the view of electron-hole pairs and p-n junctions. In short, the method in our work is expected to become a new way of effectively preparing functional inorganic Janus-like NFs.

Polydiacetylenes (PDAs) are conjugative polymers that demonstrate color changes as a response to an external stimulus. In this study, 10,12-pentacosadiynoic acid (PCDA) was mixed with a supporting polymer including poly(ethylene oxide) (PEO) and polyurethane (PU), and the mixture solution was electrospun to construct fiber composites. The electrospun fibers were then photopolymerized using UV irradiation to produce PEO-PDA and PU-PDA nanofiber mats with a fiber diameter ranging from 130 nm to 2.5 μm. The morphologies of both PEO-PDA and PU-PDA nanofibers were dependent on electrospinning parameters such as the ratio of PCDA to PEO or PCDA to PU and the total polymer concentrations. Scanning electron microscopy images showed beaded fibers of PEO-PDA and PU-PDA at 2 and 18 w/v % concentrations, respectively. Smooth fibers were found when the solvent concentration was increased to 3.75 w/v % in PEO-PDA and 25 w/v % in PU-PDA fibers. Both PEO-PDA and PU-PDA nanofiber composites demonstrated excellent colorimetric responses to the presence of Escherichia coli ATCC25922 bacterial cells and the changes in pH as external stimuli. The nanofibers underwent a rapid colorimetric response when exposed directly to E. coli ATCC25922 grown on Luria-Bertani agar. The comparison between the PEO-PDA and PU-PDA suggested that the combination of PEO and PDA is favorable because it provides a sensitive response to the presence of E. coli . The results were compared with samples of a PDA polymer in the absence of a matrix polymer. The colorimetric response was similar when the PDA polymer and the PDA nanofiber composites were exposed to pH changes, and the color change was found to occur at pH 10 and enhanced at pH 11-13. The PDA-containing nanofiber composites showed stronger colorimetric responses than those of the PDA polymer only, suggesting their potential as biosensors and chemosensors., Competing Interests: The authors declare no competing financial interest.

Polydiacetylene (PDA) is an attractive conjugated material for use in biosensors due to its unique characteristic of undergoing a blue-to-red color change in response to external stimuli. 10,12-Pentacosadiynoic acid (PCDA) and poly (ethylene oxide) (PEO) were used in this study to develop fiber composites via an electrospinning method at various mass ratios of PEO to PCDA, solution concentrations, and injection speeds. The PEO-PDA fibers in blue phase were obtained via photo-polymerization upon UV-light irritation. High mass ratios of PEO to PCDA, low polymer concentrations of spinning solution, and low injection speeds promoted fine fibers with small diameters and smooth surfaces. The colorimetric transition of the fibers was investigated when the fibers were heated at temperatures ranging from 25 °C to 120 °C. A color switch from blue to red in the fibers was observed when the fibers were heated at temperatures greater than 60 °C. The color transition was more sensitive in the fibers made with a low mass ratio of PEO to PCDA due to high fraction of PDA in the fibers. The large diameter fibers also promoted the color switch due to high reflectance area in the fibers. All of the fibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) and compared before and after the color change occurred. The colorimetric transitional mechanism is proposed to occur due to conformational changes in the PDA macromolecules.