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1.
Int J Biol Macromol ; : 131616, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38631592

RESUMO

Hydrogels have shown great potential for application in food science due to their diverse functionalities. However, most hydrogels inevitably contain toxic chemical cross-linking agent residues, posing serious food safety concerns. In this paper, a curcumin/sodium alginate/carboxymethyl chitosan hydrogels (CSCH) were prepared by self-assembly of two oppositely charged polysaccharides, carboxymethyl chitosan and sodium alginate, to form a three-dimensional network encapsulating curcumin for extending food shelf life. The network structure of the CSCH film confirmed by FTIR, XRD, and XPS was mainly formed by electrostatic interactions. The chemical stability of CSCH network encapsulated curcumin was 4.2 times greater than that of free curcumin, with excellent gas barrier, antimicrobial, antioxidant, and biosafety properties. It was found that CSCH films reduced dehydration, prevented nutrient loss, inhibited microbial growth, and lowered the respiration rate, which effectively maintained the quality of mango and prolonged its shelf-life up to 11 days. Notably, CSCH films possessed the properties of rapid recycling (10 mins) and biodegradability (53 days). This polysaccharide-based hydrogel film provides a viable strategy for the development of green and sustainable food packaging.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38605670

RESUMO

Recently, conductive hydrogels have emerged as promising materials for smart, wearable devices. However, limited mechanical properties and low sensitivity greatly restrict their lifespan. Based on the design of biomimetic-layered structure, the conductive hydrogels with nacre-mimetic structure were prepared by using layered acrylic bentonite (AABT) and phytic acid (PA) as multifunctional "brick" and "mortar" units. Among them, the unique rigid cyclic multihydroxyl structure of the "organic mortar" PA preserves both ultrastretchability (4050.02%) and high stress (563.20 kPa) of the hydrogel, which far exceeds most of the reported articles. Because of the synergistic effect of AABT and PA, the hydrogel exhibits an excellent adhesive strength (87.74 kPa). The role of AABT in the adhesive properties of hydrogels is proposed for the first time, and a general strategy for improving the adhesive properties of hydrogels by using AABT is demonstrated. Furthermore, AABT provides ion channels and PA ionizes abundant H+, conferring a high gauge factor (GF = 14.95) and excellent antimicrobial properties to the hydrogel. Also, inspired by fruit batteries, simple self-powered flexible sensors were developed. Consequently, this study provides knowledge for functional bentonite filler modified hydrogel, and the prepared multifunctional ionic conductive hydrogel shows great application potential in the field of intelligent wearable devices.

3.
Int J Biol Macromol ; 265(Pt 1): 130798, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38479674

RESUMO

Controlling ethylene production and microbial infection are key factors to prolong the shelf life of climacteric fruit. Herein, a nanocomposite film, hexanal-loaded ZIF-8/CS (HZCF) with "nano-barrier" structure, was developed by a one-pot co-crystallized of ZIF-8 in situ growth on quaternized chitosan (CS) and encapsulation of hexanal into ZIF-8 via microporous adsorption. The resultant film realized the temperature responsive release of hexanal via the steric hindrance and hierarchical pore structure as "nano-barrier", which can inhibit ethylene production in climacteric fruit on demand. Based on this, the maximum ethylene inhibition rate of HZCF was up to 52.6 %. Meanwhile, the film exhibits excellent antibacterial, mechanical, UV resistance and water retention properties, by virtue of the functional synergy between ZIF-8 and CS. Contributed to the multifunctional features, HZCF prolonged the shelf life of banana and mango for at least 16 days, which is 8 days longer than that of control fruit. More strikingly, HZCF is washable and biodegradable, which is expected to replace non-degradable plastic film. Thus, this study provides a convenient novel approach to simplify the encapsulation of active molecule on metal-organic frameworks (MOFs), develops a packaging material for high-efficient freshness preservation, and helps to alleviate the survival crisis caused by food waste.


Assuntos
Aldeídos , Quitosana , Climatério , Eliminação de Resíduos , Quitosana/farmacologia , Quitosana/química , Frutas , Temperatura , Etilenos/química , Antibacterianos/farmacologia , Embalagem de Alimentos
4.
J Mater Chem B ; 12(13): 3262-3272, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38456357

RESUMO

Traditional petroleum-based plastics have high energy consumption, require professional equipment, are non-degradable after use, and lack antibacterial properties, making it impossible to achieve long-lasting freshness in fruits and vegetables. Herein, we report a novel co-type film-forming method with low energy consumption and without production equipment, which uses PVA-borax gel as a substrate and adds a certain proportion of CMC and TA to prepare multifunctional CMC/TA@PVA-borax composite hydrogels (CTPB). The dynamic borax ester bonding and hydrogen bonding in the CTPB hydrogel results in an ultra-high tensile strength of more than 5500% and rapid self-healing within 8 s. Interestingly, hydrogels can be arbitrarily shaped and stretched like play dough and thus can be stretched into ductile films by co-type film formation. The antimicrobial properties of the hydrogel film can be attributed to the synergistic effects of TA and borax. The mussel structure of TA allows the hydrogel film to adhere directly to different surfaces for more effective bacterial killing. In addition, the hydrogel film has a high level of biosafety and biodegradability and shows good performance in fruit storage. This study provides a convenient and low-energy method for the preparation of films, which in part reduces the increasing environmental pollution caused by petroleum-based plastics.


Assuntos
Boratos , Frutas , Petróleo , Resistência à Tração , Álcool de Polivinil/química , Hidrogéis/química , Plásticos
5.
J Mater Chem B ; 12(7): 1864-1874, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38293805

RESUMO

Challenges associated with the storage and uncontrolled release of ClO2 gas present significant hurdles to its practical application. Herein, a clever strategy for self-triggering the sustained release of chlorine dioxide (ClO2) gas is proposed by crosslinking carboxymethyl chitosan (CMCS) with Zn2+ to construct a novel CMCS-Zn@NaClO2 gel with eco-friendly, environmental stability, and convenient, long term, and efficient antibacterial activity. The precursor (NaClO2) in the CMCS solution was alkaline and triggered by the acidic Zn(NO3)2·6H2O solution to achieve sustained self-triggering ClO2 release. The ClO2 gas self-release could be sustained on demand at different temperatures for at least 20 days due to the environmental structure stability of the gel. The hydrogels showed an increase in pore size after sustained release. Molecular dynamics simulations showed the spontaneous release of ClO2 gas at room temperature and the contraction of the CMCS agglomeration, which were consistent with the macroscopic behaviour. The gel displayed a long-acting and high antibacterial efficacy, resulting in a bacteria-killing rate of over 99.9% (inhibitory concentrations of 2.5 mg mL-1 against E. coli and 0.16 mg mL-1 against S. aureus). The hydrogels could effectively extend the shelf life of fruits and demonstrated an excellent wide range of antibacterial properties. This work provides a new approach to solving the storage difficulty of ClO2 gas and offers a fresh perspective on the design of materials with convenient self-triggering release by a precursor, as well as the relationship between the material microstructure and sustained-release behaviour.


Assuntos
Anti-Infecciosos , Quitosana , Escherichia coli , Preparações de Ação Retardada/farmacologia , Staphylococcus aureus , Quitosana/química , Hidrogéis/farmacologia , Hidrogéis/química , Anti-Infecciosos/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química
6.
Int J Biol Macromol ; 259(Pt 1): 129090, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38161019

RESUMO

In this work, a multifunctional preservative film of ZnO/carboxymethyl starch/chitosan (ZnO/CMS/CS) with the unique "Steel Wire Mesh" structure is fabricated by the chemical crosslinked of ZnO NPs, CMS and CS. Unlike traditional nano-filled polymer film, the formation of the "Steel Wire Mesh" structure of ZnO/CMS/CS film is based on the synergistic effect of ZnO NPs filled CMS/CS and the coordination crosslinked between CMS/CS and Zn2+ derived from ZnO NPs. Thanks to the "Steel Wire Mesh" structure, the tensile strength and water vapor barrier of 2.5ZnO/10CMS/CS film are 2.47 and 1.73 times than that of CS film, respectively. Furthermore, the transmittance of 2.5ZnO/10CMS/CS film during antifogging test is close to 89 %, confirming its excellent antifogging effects. And the 2.5ZnO/10CMS/CS film also exhibits excellent long-acting antibacterial activity (up to 202 h), so it can maintain the freshness and appearance of strawberries at least 5 days. More importantly, the 2.5ZnO/10CMS/CS film is sensitive to humidity changes, which achieves real-time humidity monitoring of the fruit storage environment. Note that the preparation method of the film is safe, simple and environmentally friendly, and its excellent degradation performance will not bring any problems of food safety and environmental pollution.


Assuntos
Quitosana , Fragaria , Amido/análogos & derivados , Óxido de Zinco , Quitosana/química , Óxido de Zinco/farmacologia , Óxido de Zinco/química , Antibacterianos/farmacologia , Antibacterianos/química , Embalagem de Alimentos
7.
Int J Biol Macromol ; 249: 126020, 2023 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-37516221

RESUMO

Ionic hydrogels used as ideal and flexible strain sensor materials should have excellent mechanical, adhesive and antimicrobial properties. However, it is challenging to achieve these multifunctional requirements simultaneously. Herein, we designed and prepared a multifunctional ionic hydrogel with a multi-length tentacle bentonite backbone to initiate the free radical polymerization of acrylic acid bentonite (AABT) and acrylamide (AAm). The interactions of covalent cross-linking, hydrogen bonding cross-linking, charge interactions and physical entanglement between hybrid polyacrylamide-AABT (PAAm-AABT), sodium carboxymethyl starch (SCMS) and PAAm form an multi-in-one hybrid supramolecular network hydrogel (CABZ). This CABZ ion-conductive hydrogel is capable of detecting weak deformation with a detection limit of 1 % strain, high tensile properties of 995 %, excellent strength of 254.5 kPa, fast response (≈0.21 s), high sensitivity of 0.86 and high conductivity of 0.37 S/m. In addition, this CABZ ion-conductive hydrogel has impressive adhesion properties with shear adhesion strength up to 50.78 kPa and broad-spectrum antibacterial properties achieved by AABT-loaded ZnO nanoparticles. Through special AABT hybrid cross-linking, the CABZ ion-conductive hydrogel achieves stable mechanical properties, highly sensitive signal response and antimicrobial properties, which will make it a good choice for flexible wearable sensor materials.


Assuntos
Anti-Infecciosos , Bentonita , Anti-Infecciosos/farmacologia , Condutividade Elétrica , Hidrogéis
8.
Int J Biol Macromol ; 243: 125145, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37268070

RESUMO

The continuous infestation of pests has seriously affected rice growth, yield and quality. How to reduce the use of pesticides and effectively control insect pests is a bottleneck problem. Herein, based on hydrogen bonding and electrostatic interactions, we posed a novel strategy to construct emamectin benzoate (EB) pesticide loading system using self-assembled phosphate-modified cellulose microspheres (CMP) and chitosan (CS). CMP provides more binding sites for EB loading and CS coating further enhances the carrier loading capacity up to 50.75 %, which jointly imparted pesticide photostability and pH-responsiveness. The retention capacity of EB-CMP@CS in rice growth soil reached 101.56-fold that of commercial EB, which effectively improved the absorption of pesticides during rice development. During the pest outbreak, EB-CMP@CS achieved effective pest control by increasing the pesticide content in rice stems and leaves, the control efficiency of the rice leaffolder (Cnaphalocrocis medinalis) reached 14-fold that of commercial EB, and could maintain the effective pest control effect during the booting stage of rice. Finally, EB-CMP@CS-treated paddy fields had improved yields and were free of pesticide residues in the rice grain. Therefore, EB-CMP@CS achieves effective control of rice leaffolder in paddy fields and has potential application value in green agricultural production.


Assuntos
Quitosana , Mariposas , Oryza , Praguicidas , Animais , Quitosana/farmacologia , Fosfatos/farmacologia , Oryza/metabolismo , Praguicidas/farmacologia
9.
Carbohydr Polym ; 316: 121073, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37321748

RESUMO

Strawberry is a seasonal and regional fruit. Thus, strawberry waste caused by spoilage and decay is an urgent problem that must be solved. Developing hydrogel films (HGF) for multifunctional food packaging can effectively slow down strawberry. Based on the carboxymethyl chitosan/sodium alginate/citric acid with excellent biocompatibility, preservation effect, and ultrafast (10 s) coating on the strawberry surface, HGF specimens were designed and prepared through the electrostatic interaction of opposite charges between polysaccharides. The prepared HGF specimen exhibited excellent low moisture permeability and antibacterial properties. Its lethality rates against both Escherichia coli and Staphylococcus aureus were more than >99 %. The HGF could keep strawberries fresh for up to 8, 19, and 48 days at 25.0, 5.0, and 0 °C, respectively, by delaying the fruits' ripening, dehydration, microbial invasion, and respiration rate. The HGF dissolved and regenerated five times still exhibited good performance. The water vapor transmission rate of the regenerative HGF could reach 98 % of that of the original HGF. The regenerative HGF could maintain the freshness of strawberries for up to 8 days at 25.0 °C. This study provides new insight into an alternative film design for convenient, green, and renewable alternative films to delay perishable fruit spoilage.


Assuntos
Quitosana , Fragaria , Alginatos/farmacologia , Quitosana/farmacologia , Reprodutibilidade dos Testes , Embalagem de Alimentos , Antibacterianos/farmacologia , Conservação de Alimentos
10.
Int J Biol Macromol ; 242(Pt 1): 124681, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37141968

RESUMO

Conventional vulcanized rubbers cause a non-negligible waste of resources due to the formation of 3D irreversible covalently cross-linked networks. The introduction of reversible covalent bonds, such as reversible disulfide bonds, into the rubber network, is an available solution to the above problem. However, the mechanical properties of rubber with only reversible disulfide bonds cannot meet most practical applications. In this paper, a strengthened bio-based epoxidized natural rubber (ENR) composite reinforced by sodium carboxymethyl cellulose (SCMC) was prepared. SCMC forms a mass of hydrogen bonds between its hydroxyl groups and the hydrophilic groups of ENR chain, which gives the ENR/2,2'-Dithiodibenzoic acid (DTSA)/SCMC composites an enhanced mechanical performance. With 20 phr SCMC, the tensile strength of the composite increases from 3.0 to 10.4 MPa, which is almost 3.5 times that of the ENR/DTSA composite without SCMC. Simultaneously, DTSA covalently cross-linked ENR with the introduction of reversible disulfide bonds, which enables the cross-linked network to rearrange its topology at low temperatures and thus endows the ENR/DTSA/SCMC composites with healing properties. The ENR/DTSA/SCMC-10 composite has a considerable healing efficiency of about 96 % after healing at 80 °C for 12 h.


Assuntos
Carboximetilcelulose Sódica , Borracha , Borracha/química , Compostos de Epóxi/química , Dissulfetos , Sódio
11.
Small ; 19(23): e2208116, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36890772

RESUMO

With the consumption of disposable electronic devices increasing, it is meaningful but also a big challenge to develop reusable and sustainable materials to replace traditional single-use sensors. Herein, a clever strategy for constructing a multifunctional sensor with 3R circulation (renewable, reusable, pollution-reducing biodegradable) is presented, in which silver nanoparticles (AgNPs) with multiple interactions are introduced into a reversible non-covalent cross-linking network composed of biocompatible and degradable carboxymethyl starch (CMS) and polyvinyl alcohol (PVA) to simultaneously obtain high mechanical conductivity and long-term antibacterial properties by a one-pot method. Surprisingly, the assembled sensor shows high sensitivity (gauge factor up to 4.02), high conductivity (0.1753 S m-1 ), low detection limit (0.5%), long-term antibacterial ability (more than 7 days), and stable sensing performance. Thus, the CMS/PVA/AgNPs sensor can not only accurately monitor a series of human behavior, but also identify handwriting recognition from different people. More importantly, the abandoned starch-based sensor can form a 3R circulation. Especially, the fully renewable film still shows excellent mechanical performance, achieving reusable without sacrificing its original function. Therefore, this work provides a new horizon for multifunctional starch-based materials as sustainable substrates for replacing traditional single-use sensors.

12.
Carbohydr Polym ; 306: 120625, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36746577

RESUMO

Natural polymers with abundant hydrophilic groups are potential candidates for humidity sensor designing. Unfortunately, most of natural polymers lack essential stretchability and high conductivity, which hinder their development in the field of flexible humidity sensor. Cooperation with rubbers and conductive nanometer materials is an effective method to make the best use of natural polymers in flexible humidity sensor. In this paper, a flexible and sensitive sensor with rapid response to humidity change is fabricated based on aldehyde-modified sodium carboxymethyl starch (ACMS), carboxylated styrene-butadiene rubber (XSBR) and Ag nanoflakes through film-forming method. The pre-prepared ACMS owns a better dispersibility in the aqueous phase and serves as reducing agent for formation of Ag nanoflakes. After the film-forming process, the composite film shows a strength of 5.66 MPa and a high stretchability with strain of 367 %. Besides, our sensor shows a rapider response to humidity change than the commercial electronic hygrometer that it takes only 1 s to respond to the humidity change from 25 % RH to 27 % RH. Therefore, the XSBR/ACMS/Ag sensor possesses an impressive sensitive response to slight sweat on human skin and breath, which could find applications in monitoring people's health and distinguish their physical condition.


Assuntos
Polímeros , Borracha , Humanos , Umidade , Água
13.
Carbohydr Polym ; 302: 120433, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36604093

RESUMO

The lack of antimicrobial effect of commercial paper coating for food packaging makes it difficult to prevent food spoilage and harms the environment by non-biodegradation. Herein, carboxymethyl cellulose (CMC) provides negatively charged sites for anchoring Ag+ and Zn2+ to grow AgNPs and ZIF-8 in situ on its molecular chains. The ZIF-8/AgNPs@CMC paper coating has excellent synergistic antibacterial activity to prolong the shelf-life of food. It not only has good thermal stability but binds closely to the paper and its adhesion force reaches 628.9 nN. Besides, the ZIF-8/AgNPs@CMC coated paper has better mechanical properties, water vapor barrier, and resists water solubility. Interestingly, due to the confinement effect of ZIF-8, the cumulative release of AgNPs after 168 h is only 2.66 % to avoid possible food safety risks. Especially, the coating can be almost biodegraded in the soil after 30 days, which provides the possibility to replace the non-biodegradable coatings in food packaging.


Assuntos
Antibacterianos , Carboximetilcelulose Sódica , Carboximetilcelulose Sódica/farmacologia , Antibacterianos/farmacologia , Embalagem de Alimentos , Fenômenos Mecânicos , Solubilidade
14.
Carbohydr Polym ; 301(Pt A): 120317, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36436862

RESUMO

Pathogens transmitted through the water environment pose a great threat to human health. Hence developing more reliable and efficient antibacterial materials to eliminate bacterium in water environments is urgent. Herein, we posed a novel strategy of interweaving carboxymethyl chitosan (CMCS) and Ag/Cu-MOFs to construct renewable Ag/Cu-BTC@CMCS composite beads with rapid sterilization, long-term antibacterial effects and high biosafety. Characterizations revealed that CMCS and bimetallic MOFs act as the "warehouses" of metal ions and played key roles in anchoring, storage, delivery, and controlled release of metal ions. The synergistic antibacterial effect achieved by the combination of Ag+ and Cu2+ provides the composite beads with high antibacterial efficiency, resulting in low minimum inhibitory concentrations (0.32 mg/mL against E. coli and 0.16 mg/mL against S. aureus) and over 99.9 % bacteria killing rate. Benefiting from the rapid release of metal ions from polymer chains and the long-term release from MOFs, the composite beads can effectively sterilize the simulated swimming pool water in 2 h and persistently inhibit bacterial reproduction over 48 h, and show a safe level of residual heavy metals because of the chelation of CMCS. This work provides new insights and promises a strategy for the design and commercial application of novel water fungicides.


Assuntos
Quitosana , Metais Pesados , Humanos , Quitosana/farmacologia , Staphylococcus aureus , Escherichia coli , Antibacterianos/farmacologia , Metais Pesados/farmacologia , Água , Esterilização
15.
ACS Appl Mater Interfaces ; 14(50): 56074-56086, 2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36508579

RESUMO

Most electronic skins (e-skins) show unique performance or possess sensory functions. The raw materials used for their preparation are potentially toxic or harmful, and there may be problems such as poor compatibility between the conductive fillers and polymers. In this paper, a silver-loaded nanocomposite film (PVA/CMS/vanillin/nanoAg) was prepared by the in situ reduction method in a greener route. The mechanical properties of this nanocomposite film had improved with a tensile strength of 30.95 MPa, an elongation at break of 101.9%, and a Young's modulus of 10.62 MPa. In the composite matrix, a cross-linked network was constructed based on the coordination and hydrogen bonds, which was conducive to the stability of the reduced AgNPs and AgNWs. When applied as an e-skin in humidity/sweat sensors and wearable electronics, the nanocomposite film responds to humidity within 60 s and records the electric signals of human joint movements and skin sweating with a response range of 0-140% to strain at 93% RH. This kind of e-skin has excellent antibacterial and antioxidant activities and shows an outstanding ultraviolet-proof performance, which provides a greener promising reference route for the design of wearable e-skins to monitor the health and movements of humans.


Assuntos
Sudorese , Dispositivos Eletrônicos Vestíveis , Humanos , Antioxidantes/farmacologia , Antioxidantes/análise , Suor/química , Umidade , Eletrônica , Antibacterianos/farmacologia , Antibacterianos/análise
16.
Carbohydr Polym ; 297: 120041, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36184148

RESUMO

Overuse of pesticides is an urgent issue to be solved in sustainable agriculture. Based on the synergistic drug loading effect of ß-cyclodextrin (ß-CD) encapsulation and alginate (Alg) cross-linking, a new environment-responsive drug delivery system (TMX-loaded Alg/ß-CD) was constructed. The relationship between carrier structure and solubility of thiamethoxam (TMX) was researched by molecular simulation. ß-CD has good binding affinity with TMX, which can increase TMX solubility by 40 %. Further co-loading with alginate could double the drug loading of the cyclodextrin inclusion complex up to 41 %. TMX-loaded Alg/ß-CD exhibits excellent environment-responsive controlled-release performance, and TMX sustained release time is 7.5 times longer than that of commercial agents. The pest control efficacy of TMX-loaded Alg/ß-CD is 20 days longer than that of commercial TMX, and the crops has no pesticide residues after using. This study provides a promising strategy for the commercial application of polysaccharide in pest control and pesticide reduction.


Assuntos
Praguicidas , beta-Ciclodextrinas , Alginatos/química , Preparações de Ação Retardada/química , Polissacarídeos , Tamoxifeno/química , Tiametoxam
17.
Food Chem ; 395: 133614, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-35810627

RESUMO

The global annual fruit and vegetable waste accounts for more than half of food waste, and the main cause of this waste is the deterioration of fruit and vegetable. In addition, fruit spoilage can produce foodborne illnesses and pose a public health threat. In order to guarantee the quality and safety of fruits in the fruit supply chain. We prepared multifunctional silver based metal-organic frameworks@carboxymethyl filter paper (Ag-MOFs@CMFP) composite paper by in situ synthesis. The composite paper used in fruit packaging can effectively slows down fruit deterioration. Besides, Ag-MOFs@CMFP composite paper can reflect the quality of the fruit by detecting changes in humidity, which has yet to be reported elsewhere. Significantly, transmitting the humidity response signal to the mobile phone can realize remote real-time wireless monitoring of fruit quality. This work may contribute to achieve the integration of real-time wireless monitoring, preservation and packaging for fruit-supply chain.


Assuntos
Frutas , Eliminação de Resíduos , Conservação de Alimentos , Prata , Verduras
18.
Int J Biol Macromol ; 214: 181-191, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35700848

RESUMO

The spoilage of fruit is one of the most important causes of fruit waste. High humidity by fresh fruit respiration leads to bacterial reproduction, which is the key factor of products corruption. Herein, a biological multifunctional film (Cur-HKUST-1@CMS/PVA) for fruits preservation with a high moisture environment was developed by cross-linking carboxymethyl starch (CMS)/polyvinyl alcohol (PVA) with MOF-199 (HKUST-1), and loaded with curcumin. The hydrophilic CMS facilitates water adsorption and moisture can stimulate curcumin release from HKUST-1. HKUST-1 not only acts as curcumin carriers but also forms synergistic antibacterial with curcumin to improve the antibacterial activity of the composites. XRD and SEM demonstrated that moisture disrupts the structure of HKUST-1 and releases curcumin and the results showed that the release of curcumin increased from 25.11 % to 58.32 % after moisture stimulation. In addition, Cur-HKUST-1@CMS/PVA had excellent antibacterial activity and antioxidant ability. As validation, the film can keep pitaya and avocado freshness at least 4 days longer than the control, confirming the effectiveness of Cur-HKUST-1@CMS/PVA in preventing fruit decay. Consequently, Cur-HKUST-1@CMS/PVA is a promising active packaging material for improve the shelf life of perishable fruits.


Assuntos
Curcumina , Antibacterianos/química , Antibacterianos/farmacologia , Curcumina/química , Curcumina/farmacologia , Frutas , Estruturas Metalorgânicas , Álcool de Polivinil/química , Amido/análogos & derivados
19.
Int J Biol Macromol ; 214: 338-347, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35716789

RESUMO

The microstructure changes (such as micro defects and free volume, etc.) is a deep factor that determines the sustained release behavior of polymer film. However, there are few reports exploring the micro defects of sustained-release materials. Herein, we develop a facile method to non-destructive monitoring and sustained-release ethylene within chitosan. The comprehensive means of positron annihilation lifetime spectroscopy, atomic force microscopy and Raman spectrums are performed together to study the microstructures change of ethylene sustained-release and its mechanism. When ethylene is in chitosan film, it shows good ripening performance and mechanical properties. The sustained-release ethylene improves its bioavailability and can control the fruit-ripening on-demand. More importantly, the microstructural changes of cavities have a significant impact on the sustained release of ethylene, due to the creation of cavities, the free volume of positrons undergoes a process of increasing from less to more and then gradually decreasing, reaching a maximum at 120 h. Furthermore, the ethephon/chitosan film could on-demand control the ripening time of mangoes and bananas. Therefore, this research presents a comprehensive means to study of microstructure change monitoring and controllable sustained release, and provides the possibility to solve the problem of on-demand ripening of fruit and reducing pesticide residue.


Assuntos
Quitosana , Frutas , Quitosana/química , Preparações de Ação Retardada , Etilenos/química , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Compostos Organofosforados , Proteínas de Plantas/genética
20.
Adv Mater ; 34(1): e2107309, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34648668

RESUMO

Recently, flexible wearable electronic devices have attracted immense interest as an alternative for conventional rigid metallic conductors in personal healthcare monitoring, human motion detection, and sensory skins, owing to their intrinsic characteristics. However, the practical applications of most wearable sensors are generally limited by their poor stretchability and sensitivity, unsatisfactory strength, lower conductivity, and single sensory function. Here a hydrogen bond cross-linked network based on carboxylic styrene butadiene rubber (XSBR) and hydrophilic sericin (SS) non-covalently modified carbon nanotubes (CNTs) is rationally designed and then fabricated into multi-functional sensors. The resultant versatile sensors are able to detect both weak and large deformations, which owns a low detection limit of 1% strain, high stretchability up to 217%, superior strength of 12.58 MPa, high sensitivity with a gauge factor up to 25.98, high conductivity of 0.071 S m-1 , and lower percolation threshold of 0.504 wt%. Moreover, the prepared sensors also possess an impressively thermal response (0.01636 °C-1 ) and realize the application in the measurement of human body temperature. The multifunctional and scalable XSBR/SSCNT sensor with the integrated tracking capabilities of real-time and in situ physiological signals, providing a promising route to develop wearable artificial intelligence in human health and sporting applications.


Assuntos
Nanotubos de Carbono , Dispositivos Eletrônicos Vestíveis , Inteligência Artificial , Humanos , Movimento (Física) , Nanotubos de Carbono/química , Borracha , Temperatura Cutânea
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