A multifunctional nanozyme hydrogel film with antibacterial and antioxidant activity for fruit packaging and freshness preservation.

Multifunctional and antimicrobial carboxymethyl cellulose-based active hydrogel film for fruits packaging and preservation

Strong, tough, antibacterial, antioxidant, biodegradable multi-functional intelligent hydrogel film for real-time detection and maintenance of salmon freshness.

Polyvinyl alcohol-based multifunctional hydrogel film: a novel strategy for food preservation packaging

Responsive polymer thin films

Aloe vera extracts, consisting of active compounds that decrease pain and inflammation and stimulate skin growth and repair, are selected as a drug model in this work. Polyvinyl alcohol (PVA) was used as base material. Release profiles of Aloe vera extracts from PVA electrospun fibers were compared to those from PVA hydrogel films prepared by freezing/thawing method. This method provided a physical crosslinked polymer. The concentration of PVA solution used for electrospinning and hydrogel preparation was 10% wt with different contents of Aloe vera extracts (0, 30, 50, 70 and 90% w/w). The properties of electrospun fibers and hydrogel films were evaluated in terms of morphology, chemical structure, swelling behavior and release profiles. The morphological properties of electrospun fibers and hydrogel film were observed by SEM. Electrospun fibers were smoothly round, high surface area, and non-woven, while hydrogel film possessed rough surface and was covered with porous. Fourier transform infrared spectroscopic measurement exhibited the existence of relevant functional groups of both PVA and Aloe vera extracts. The results showed relevant functional groups of Aloe vera extracts in both electrospun fibers and hydrogel film. The release of Aloe vera extracts from both electrospun fibers and hydrogel film was evaluated in phosphate buffer of pH 5.5 at 25 °C and was monitored by UV–vis spectroscopy. It was revealed that as the content of Aloe vera increased, the amount of Aloe vera extracts released from electrospun fibers decreased. This result contrasts with the release of aloe vera from hydrogel film which increased when the content of aloe vera increased. It was also noticed that the amount of Aloe vera extracts released from electrospun fibers was more than that from hydrogel films at 600 minutes. The results also showed that the releasing rate of Aloe vera from electrospun fibers was faster than that from hydrogel films. This is probably because electrospun fibers had much higher surface area than that of hydrogel film thus, the release was faster.

Fabrication and application of multifunctional conductive hydrogel film for wearable sensors via efficient freeze-thaw cycling and annealing process

High-performance carboxymethyl cellulose-based hydrogel film for food packaging and preservation system

AgNPs-loaded chitosan/sodium alginate hydrogel film by in-situ green reduction with tannins for enhancing antibacterial activity

Sustainable packaging has given vital importance for food protection, food safety, food property maintenance, regulatory compliance, and cost-effectiveness, with the aim of supporting long-term human and ecological health. On the other hand, hydrogel-based food package exhibited numerous advantages to protect fresh fruits and vegetables and continued to enhance their shelf life at ambient temperature. Hence, an effort has been given to discuss the development of bacterial cellulose (BCs)-based polysaccharide-polyol complex biomaterial for sustainable food packaging materials. A novel polymeric hydrogel film is prepared by modifying the existing polyvinylpyrrolidone—sodium carboxymethylcellulose (PVP-CMC) hydrogel film with the addition of BCs, which is designated as ‘PVP-CMC-BCs’. This book chapter mainly describes the use and efficacy of BCs-based hydrogel film for improved shelf life of soft and delicate fruits and vegetables. The efficacy of ‘PVP-CMC-BCs’ hydrogel film is evaluated on the basis of the ‘shelf life’ of table grapes, spinach, tomatoes, etc., as a confirmation test. It is evident from the results that ‘PVP-CMC-BCs’ hydrogel film can keep mostly all kinds of delicate fresh fruits and vegetables for 30 days without any physiological degradation in appearance. Thus, ‘PVP-CMC-BCs’ hydrogel film can be considered as an alternative to the conventional plastic packaging. Moreover, the present study introduces a new generation of bioplastic hydrogel film for sustainable food packaging for elusive agro-bio products.

ABSTRACTThe present work aimed to develop polyvinyl alcohol (PVA) hydrogel films with physically crosslinking through controllable entanglement density of the polymer chains. The viscoelasticity of PVA aqueous solutions was investigated over a broad range in molecular weight. The chain length between the crosslinks in the hydrogel () and entanglement density was determined by the plateau modulus (G'). The value of () increased with the PVA molecular weight, which can be attributed to the enhanced entanglement associated with the hydrogen bonds between inter‐ and interchains. The melting and crystallization of the transparent PVA hydrogel films showed that the crystallinity was below 30%, which indicated that microcrystallites formed. Therefore, the entanglement effect and microcrystallization enhanced the stable crosslinked hydrogel network, which further improved by an increase in the molecular weight. Altogether, the PVA with the molecular weight higher than 88,000 g/mol can be envisioned as a promising material for preparing the hydrogel film possessing excellent performance. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1673–1683

This study is based on creating and assessing citric acid (CA) cross-linked biopolymer composite Metronidazole (MTZ) loaded hydrogel films for wound healing applications. Different concentrations of sodium carboxymethyl cellulose (NaCMC), hydroxypropylmethyl cellulose (HPMC), and polyvinyl alcohol (PVA) were used to create hydrogel films using the solvent cast method. FTIR verified the chemical cross-linking (ester bond) between NaCMC and HPMC. WVTR for hydrogel films ranged between 167.10 ± 33 to 341.41 ± 18 g/m2 /day.S0 (Control) hydrogel film shows lowest tensile strength which indicates poor mechanical properties of this hydrogel film.Hydrogel films with more concentration of HPMC show a high swelling index initially but get dissolved completely within one hour, as the swelling index is inversely proportional to cross-linking density thus these results indicate poor cross-linking in S4 to S8 batches of film. Scanning Electron Microscopy (SEM), results shows drug particles on surface of control (S0) hydrogel film reveal absence of crosslinker. CA crosslinked hydrogel film show smooth and uniform morphology.X-ray diffraction (XRD) observed the crystalline nature of drug and amorphous nature of hydrogel film. In vitro studies reveal sustained release of MTZ from hydrogel films. Antibacterial study and Antimicrobial activity were investigated against Bacteriod fragilis and Escherichia coli. The hemocompatibility test reveals the biocompatibility of cross-linked hydrogel films. Overall, outcomes strongly recommended the prospective use of prepared biopolymer composite hydrogel films in wound healing applications.

A self-matching, ultra-fast film forming and washable removal bio-crosslinked hydrogel films for perishable fruits

‘Gouda cheese’ is one of the most popular varieties of cheese eaten worldwide. The preservation problem of gouda arises due to microbial contamination and infestation. Therefore, essential oil (EO) based PVP-CMC-BC-GG hydrogel film was prepared to solve the problem and to extend the shelf-life of ‘Gouda cheese’. Anthocyanin (isolated from red cabbage) based pH stickers are integrated into the packaging system to recognize the spoilage of ‘cheese’. EOs (clove and/or cinnamon) are added to PVP-CMC-BC-GG hydrogel film to improve its antimicrobial, physical, mechanical, and thermal properties as well as shelf-life of cheese. The films are assessed based on their physical, structural, and functional properties, real-time assessment on cheese, and biodegradability. The results revealed that although the addition of oils to the PVP-CMC-BC-GG hydrogel films enhanced its mechanical, hydrophobic, and antimicrobial properties, the biodegradability of PVP-CMC-BC-GG films declined with the addition of EOs. The thermal properties remained the same irrespective of the addition of EOs. The shelf life of cheese was extended for more than 10–12 days, inside the PVP-CMC-BC-GG hydrogel sachet compared to the conventional PE packaging system. Hence the use of the PVP-CMC-BC-GG sachet (containing EO or without EO) is recommended for cheese packaging along with the use of PVP-CMC-BC-GG anthocyanin bio stickers for monitoring the quality of cheese.

Skin wound management is an important issue in the medical community. Herein, we report a multifunctional film with many advanced features as a dressing for the healing of wounds. The dressing was made using chitosan and poly(acrylamide) (pAAm) hydrogel in order to form a double network (DN) hydrogel film. Compared to the pure chitosan hydrogel, which is fragile, the added pAAm network conferred excellent mechanical capability to the composite film, making it flexible and easy to treat. By further doping the hydrogel with carbon nanotubes and drugs, the film could promote wound healing. Animal experiments demonstrated that the DN hydrogel film could reduce inflammation and promote tissue regeneration. Thus, this film is promising as a treatment for wound healing.

This study synthesized poly(vinyl alcohol)/carboxymethyl chitosan/cyanidin (PVA/CMCS/CY) hydrogel films. First, PVA and CMCS were used to synthesize hydrogel films by ultraviolet irradiation. Meanwhile, CY was in situ combined into the hydrogel films through the electrostatic attraction between CMCS and CY. Next, the products were analyzed using Fourier-transform infrared spectroscopy, scanning electron microscopy, contact angle test, swelling analysis, and mechanical property test. The results revealed that compared with PVA/CMCS hydrogel films, the PVA/CMCS/CY hydrogel films had an interporous structure and good swelling and mechanical properties. Moreover, the drug release experiments demonstrated that the PVA/CMCS/CY hydrogel films had a CY encapsulation efficiency of 33.5% with a sustained CY release of up to 60 h. Furthermore, the examined antibacterial activities against Staphylococcus aureus and Escherichia coli showed that the porous PVA/CMCS/CY hydrogel films exhibited a certain inhibition. Cell viability experiments demonstrated that the PVA/CMCS/CY films displayed no obvious cytotoxicity to human umbilical vein endothelial cells.