Myoglobin entrapment in poly(vinyl alcohol) dense membranes

Figueiredo, Kátia Cecília de Souza; Alves, Tito Lívio Moitinho; Borges, Cristiano Piacsek

doi:10.1590/0104-6632.20140313s00002307

Cited by 7 publications

(3 citation statements)

References 25 publications

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“…Since the magnitude of H f is related to the crystallinity degree of the samples, it is safe to argue that the crystallinity degree of the samples decreases as the crosslinking time does. This thermal behavior is attributed to the interaction between the GA molecules and the PVA polymer chains that lead to a decrease in the ability of the PVA polymeric chains to reorder themselves in the form of crystallites that participate in the fusion process, as it has been reported in similar works involving PVA membranes . In fact, excessive crosslinking times have been associated to a PVA branching; which can promote a diminishing on the crystal thickness .…”

Section: Resultsmentioning

confidence: 72%

Thermal stability of the immobilization process of horseradish peroxidase in electrospun polymeric nanofibers

Rodríguez-deLuna

Moreno-Cortez

Garza-Navarro

et al. 2017

J of Applied Polymer Sci

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The horseradish peroxidase enzyme (type VI 250 U mg−1) was encapsulated in polymeric nanofibers using the electrospinning technique and successfully immobilized by the exposure to glutaraldehyde (GA) vapor in order to create covalent bonds between the polyivinilalcohol (PVA) polymeric chains and the enzyme molecules. The morphology of the nanofibers was analyzed by scanning electron microscopy (SEM) showing a diameter in the range of 100–200 nm. The presence of the enzyme in the electrospun nanofibers was confirmed by infrared spectroscopy (FTIR). The optimum crosslinking time was 1 h of exposure to GA vapor. The maximum percentage of the retained protein and the enzyme activity was obtained using the lowest initial enzyme concentration. The enzyme activity of the sample was retained after four reuse cycles. Differential scanning calorimetry (DSC) was used to study the thermal stability of the samples. The thermal study of the immobilized HRP enzyme provide for the first time additional information regarding the interaction of the HRP enzyme molecules with the PVA chains of the nanofiber matrix, as well as the effect of the crosslinking time in the glass transition temperature and the heat of fusion of the samples. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44811.

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Section: Resultsmentioning

confidence: 72%

Thermal stability of the immobilization process of horseradish peroxidase in electrospun polymeric nanofibers

Rodríguez-deLuna

Moreno-Cortez

Garza-Navarro

et al. 2017

J of Applied Polymer Sci

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“…A broad band around 3329 cm −1 was linked to O−H stretching from the hydrogen bonded band. 62 The vibration bands between 3000 and 2840 cm −1 were related to the C−H stretching of alkyl groups. 63 The peak at 1142 cm −1 referred to the C−O stretching vibration, which mostly corresponds to crystallinity of PVA.…”

Section: Acs Applied Bio Materialsmentioning

confidence: 99%

Development of a Long-Term Drug Delivery System with Levonorgestrel-Loaded Chitosan Microspheres Embedded in Poly(vinyl alcohol) Hydrogel

Long

Etxabide

Kornelsen

et al. 2019

ACS Appl. Bio Mater.

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This study reports on the fabrication of a controlled release system for the delivery of levonorgestrel (LNG) for long-term contraception. LNG was encapsulated in chemically cross-linked chitosan (CS) microspheres, and microspheres presented a spherical geometry with a good particle size distribution (polydispersity index (PDI) < 0.1). The LNG-CS microspheres were classified based on their particle size range, <63, 63−125, and 125−300 μm, where the 125−300 μm particles were selected to be incorporated into a physically cross-linked and annealed PVA hydrogel matrix to prolong the drug release. PVA concentrations and the annealing treatment influenced the swelling behavior of PVA hydrogels. Fourier transform infrared (FTIR) spectroscopy indicated that CS was successfully crosslinked through the formation of a Schiff base; the PVA hydrogel was formed through hydrogen bonding without reacting with LNG, which was only physically entrapped, thus maintaining its stability. Differential scanning calorimetry (DSC) showed that freeze−thaw and annealing processes increased the degree of crystallinity in the PVA hydrogel. In vitro drug release assessments for all formulations showed zero order without any burst release. Over a period of 100 days, 34, 27, and 21% of LNG was released from the CS-LNG microspheres in the size ranges < 63, 63−125, and 125−300 μm, respectively, while only 14, 11, and 9% of LNG was released when the CS-LNG microspheres were incorporated into 10, 15, and 20% PVA hydrogels, respectively. The drug release kinetics exhibited both diffusion-and swelling-controlled mechanisms following the Korsmeyer−Peppas model. This work presents a promising delivery system for long-term contraception with controlled zero-order release behaviors.

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“…This was usually related to polymer chains generated through reaction between hydroxyl side groups and breakage of cross‐links. [ 22,49 ] Tp2 of ZHF (Figure 4(A)[b–d]) were in the range of 334 ± 5°C, which were higher than that of HF by about 50°C. This result indicated that thermal stability of the composite films was improved by loading zeolite.…”

Section: Resultsmentioning

confidence: 99%

Precisely controlled delivery of plant hormone using poly(vinyl alcohol)/zeolite A hydrofilm composite

Viboonratanasri

Thongdee

Prajuabsuk

et al. 2021

Polymer Engineering & Sci

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Programmable release of a plant hormone, 1‐naphthylacetic acid (NAA), could be achieved by using a novel zeolite–hydrofilm (ZHF) composite. The ZHF was prepared using poly(vinyl alcohol) and glutaraldehyde as a cross‐linking agent with the addition of different amounts of zeolite A (0, 1.5, 2.0, 2.5, and 3.0 wt%). This reveals that ZHF was formed as a phase‐separated microcomposite with chemical interactions between zeolite A and polymer matrix. We found that the composite film with 2.5 wt% zeolite A had the largest pore size, which exhibited the highest water absorbency and the longest water retention time of over 7 h with high thermal and mechanical stabilities. Release profile displayed rapid desorption of NAA from the film at the initial stage, followed by sustained release thereafter. This behavior was explained by the Korsmeyer–Peppas model with a predominant mechanism of simple Fickian diffusion. Additionally, ZHF with NAA could effectively enhance adventitious root formation of Ocimum basilicum Linn. (sweet basil) cuttings due to accurate releasing NAA and time duration for releasing plant hormone. Finally, the NAA released at the film surface could be in a controlled manner with less negative impact on plant and environment.

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Myoglobin entrapment in poly(vinyl alcohol) dense membranes

Cited by 7 publications

References 25 publications

Thermal stability of the immobilization process of horseradish peroxidase in electrospun polymeric nanofibers

Thermal stability of the immobilization process of horseradish peroxidase in electrospun polymeric nanofibers

Development of a Long-Term Drug Delivery System with Levonorgestrel-Loaded Chitosan Microspheres Embedded in Poly(vinyl alcohol) Hydrogel

Precisely controlled delivery of plant hormone using poly(vinyl alcohol)/zeolite A hydrofilm composite

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