In situ self-assembly chitosan/ε-polylysine bionanocomposite film with enhanced antimicrobial properties for food packaging

Chitosan films with olive leaf extract (OLE) incorporated at different concentrations were characterized regarding their antimicrobial, antioxidant and some relevant physical properties (i.e., solubility, water vapor permeability, and tensile properties). Results indicate that the active films have substantial antimicrobial activity against Listeria monocytogenes and Campylobacter jejuni mostly extending the microorganisms lag phase. A lower level of inhibition was found in the case of Escherichia coli. However, the OLE seems not to improve the intrinsic antimicrobial properties of the chitosan itself, except for C. jejuni. These results were confirmed with in situ testing using chicken. The chitosan films with OLE exhibited antioxidant activity, increasing with the OLE concentration, from 0.04 to 0.15 g/L ascorbic acid equivalents, corresponding to films with 10%–30% OLE relative to the chitosan. Chitosan films loaded with OLE exhibited a higher solubility in food simulants and a reduced permeability against water vapor. Overall, the combination of OLE and chitosan allows to obtain a promising active bio-based packaging solution for addressing safety and quality issues.

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Eco-Friendly ZnO/Chitosan Bionanocomposites Films for Packaging of Fresh Poultry Meat

Coatings ◽

10.3390/coatings10020110 ◽

2020 ◽

Vol 10 (2) ◽

pp. 110 ◽

Cited By ~ 7

Author(s):

Victor Gomes Lauriano Souza ◽

Carolina Rodrigues ◽

Sara Valente ◽

Catarina Pimenta ◽

João Ricardo Afonso Pires ◽

...

Keyword(s):

Food Packaging ◽

Antioxidant Properties ◽

Antimicrobial Properties ◽

Poultry Meat ◽

Zno Nps ◽

Food Preservatives ◽

Active Food Packaging ◽

Apple Peel

The advances on the development of novel materials capable to enhance the shelf life of food products may contribute to reduce the current worldwide food waste problem. Zinc oxide nanoparticles (ZnO NPs) are considered GRAS (Generally Recognized as Safe) by the Food and Drug Administration (FDA) and due to their good antimicrobial properties are suitable to be applied as active compounds in food packaging. ZnO NPs were synthesized to be tested in active bionanocomposites through an eco-friendlier route using apple peel wastes. This work aimed to develop bionanocomposites based on chitosan and incorporated with ZnO NPs to characterize its bioactivity via in vitro and in situ studies, using fresh poultry meat as the food matrix. Overall, bio-based biodegradable films presented good antimicrobial activity, being the intrinsic antimicrobial properties of chitosan enhanced by the ZnO NPs added on the system. When used as primary packaging of the meat, the samples protected with the films presented a decrease on the deterioration speed, which was represented by the preservation of the initial reddish color of the meat and reduction on the oxidation process and microbiological growth. The nanoparticles enhanced especially the antioxidant properties of the films and proved to be potential food preservatives agents to be used in active food packaging.

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In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083035 ◽

1978 ◽

Vol 36 (2) ◽

pp. 434-435

Author(s):

D. Reis ◽

B. Vian ◽

J. C. Roland

Keyword(s):

Cell Wall ◽

Self Assembly ◽

Plant Cell Wall ◽

Higher Plants ◽

Three Dimensional ◽

Cytochemical Study ◽

Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

10.26434/chemrxiv.7098695 ◽

2018 ◽

Author(s):

Elaine A. Kelly ◽

Judith E. Houston ◽

Rachel Evans

Keyword(s):

Real Time ◽

Absorption Spectroscopy ◽

Self Assembly ◽

Uv Light ◽

Wormlike Micelles ◽

Tetraethylene Glycol ◽

Light Illumination ◽

First Time ◽

Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such asdrug delivery and micellar catalysis. Currently, their behaviour in the equilibrium cis-and trans-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C8AzoOC8E4) using small-angle neutron scattering (SANS). We show that the incorporation of in-situUV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C8AzoOC8E4could switch between wormlike micelles (transnative state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked in-situthrough combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

10.26434/chemrxiv.9876395.v1 ◽

2019 ◽

Author(s):

Hao Wu ◽

Jeffrey Ting ◽

Siqi Meng ◽

Matthew Tirrell

Keyword(s):

Small Angle ◽

Self Assembly ◽

Electrostatic Interactions ◽

Polyelectrolyte Complex ◽

Time Resolved ◽

X Ray ◽

X Ray Scattering ◽

Kinetics Of ◽

Ray Scattering

We have directly observed the in situ self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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Development of In Situ Self-Assembly Nanoparticles to Encapsulate Lopinavir and Ritonavir for Long-Acting Subcutaneous Injection

Pharmaceutics ◽

10.3390/pharmaceutics13060904 ◽

2021 ◽

Vol 13 (6) ◽

pp. 904

Author(s):

Irin Tanaudommongkon ◽

Asama Tanaudommongkon ◽

Xiaowei Dong

Keyword(s):

Sustained Release ◽

Trough Concentration ◽

Self Assembly ◽

Subcutaneous Injection ◽

Drug Loading ◽

Entrapment Efficiency ◽

Long Acting

Most antiretroviral medications for human immunodeficiency virus treatment and prevention require high levels of patient adherence, such that medications need to be administered daily without missing doses. Here, a long-acting subcutaneous injection of lopinavir (LPV) in combination with ritonavir (RTV) using in situ self-assembly nanoparticles (ISNPs) was developed to potentially overcome adherence barriers. The ISNP approach can improve the pharmacokinetic profiles of the drugs. The ISNPs were characterized in terms of particle size, drug entrapment efficiency, drug loading, in vitro release study, and in vivo pharmacokinetic study. LPV/RTV ISNPs were 167.8 nm in size, with a polydispersity index of less than 0.35. The entrapment efficiency was over 98% for both LPV and RTV, with drug loadings of 25% LPV and 6.3% RTV. A slow release rate of LPV was observed at about 20% on day 5, followed by a sustained release beyond 14 days. RTV released faster than LPV in the first 5 days and slower than LPV thereafter. LPV trough concentration remained above 160 ng/mL and RTV trough concentration was above 50 ng/mL after 6 days with one subcutaneous injection. Overall, the ISNP-based LPV/RTV injection showed sustained release profiles in both in vitro and in vivo studies.

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Injectable Drug Delivery System Based on In Situ Self‐Assembly of Liquid Star Polyethylene Glycol–Poly(lactic‐ co ‐glycolic acid)

Advanced NanoBiomed Research ◽

10.1002/anbr.202170033 ◽

2021 ◽

Vol 1 (3) ◽

pp. 2170033

Author(s):

Bat-hen Eylon ◽

Alona Shagan ◽

Ayelet Shabtay-Orbach ◽

Adi Gross ◽

Boaz Mizrahi

Keyword(s):

Drug Delivery ◽

Polyethylene Glycol ◽

Drug Delivery System ◽

Delivery System ◽

Self Assembly ◽

Glycolic Acid ◽

Injectable Drug

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Sputter-Deposited Ag Nanoparticles on Electrospun PCL Scaffolds: Morphology, Wettability and Antibacterial Activity

Coatings ◽

10.3390/coatings11030345 ◽

2021 ◽

Vol 11 (3) ◽

pp. 345

Author(s):

Daniele Valerini ◽

Loredana Tammaro ◽

Roberta Vitali ◽

Gloria Guillot ◽

Antonio Rinaldi

Keyword(s):

Ag Nanoparticles ◽

Food Packaging ◽

Antimicrobial Agents ◽

Antimicrobial Properties ◽

Deposition Process ◽

Polymer Fibers ◽

Antibacterial Action ◽

Porous Scaffolds ◽

Electrospinning Technique ◽

Sputtering Deposition

Porous scaffolds made of biocompatible and environmental-friendly polymer fibers with diameters in the nano/micro range can find applications in a wide variety of sectors, spanning from the biomedical field to textiles and so on. Their development has received a boost in the last decades thanks to advances in the production methods, such as the electrospinning technique. Conferring antimicrobial properties to these fibrous structures is a primary requirement for many of their applications, but the addition of antimicrobial agents by wet methods can present a series of drawbacks. In this work, strong antibacterial action is successfully provided to electrospun polycaprolactone (PCL) scaffolds by silver (Ag) addition through a simple and flexible way, namely the sputtering deposition of silver onto the PCL fibers. SEM-EDS analyses demonstrate that the polymer fibers get coated by Ag nanoparticles without undergoing any alteration of their morphological integrity upon the deposition process. The influence on wettability is evaluated with polar (water) and non-polar (diiodomethane) liquids, evidencing that this coating method allows preserving the hydrophobic character of the PCL polymer. Excellent antibacterial action (reduction > 99.995% in 4 h) is demonstrated against Escherichia coli. The easy fabrication of these PCL-Ag mats can be applicable to the production of biomedical devices, bioremediation and antifouling systems in filtration, personal protective equipment (PPE), food packaging materials, etc.

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Effect of Na- and Organo-Modified Montmorillonite/Essential Oil Nanohybrids on the Kinetics of the In Situ Radical Polymerization of Styrene

Nanomaterials ◽

10.3390/nano11020474 ◽

2021 ◽

Vol 11 (2) ◽

pp. 474

Author(s):

Ioannis S. Tsagkalias ◽

Alexandra Loukidi ◽

Stella Chatzimichailidou ◽

Constantinos E. Salmas ◽

Aris E. Giannakas ◽

...

Keyword(s):

Essential Oil ◽

Radical Polymerization ◽

Food Packaging ◽

In Situ Polymerization ◽

Average Molecular Weight ◽

Monomer Conversion ◽

Hydroxyl Groups ◽

Modified Montmorillonite ◽

Kinetics Of

The great concern about the use of hazardous additives in food packaging materials has shown the way to new bio-based materials, such as nanoclays incorporating bioactive essential oils (EO). One of the still unresolved issues is the proper incorporation of these materials into a polymeric matrix. The in situ polymerization seems to be a promising technique, not requiring high temperatures or toxic solvents. Therefore, in this study, the bulk radical polymerization of styrene was investigated in the presence of sodium montmorillonite (NaMMT) and organo-modified montmorillonite (orgMMT) including thyme (TO), oregano (OO), and basil (BO) essential oil. It was found that the hydroxyl groups present in the main ingredients of TO and OO may participate in side retardation reactions leading to lower polymerization rates (measured gravimetrically by the variation of monomer conversion with time) accompanied by higher polymer average molecular weight (measured via GPC). The use of BO did not seem to affect significantly the polymerization kinetics and polymer MWD. These results were verified from independent experiments using model compounds, thymol, carvacrol and estragol instead of the clays. Partially intercalated structures were revealed from XRD scans. The glass transition temperature (from DSC) and the thermal stability (from TGA) of the nanocomposites formed were slightly increased from 95 to 98 °C and from 435 to 445 °C, respectively. Finally, better dispersion was observed when orgMMT was added instead of NaMMT.

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An In-Situ Reaction Route to Molecular Level Dispersed Bisimide and ZnO Nanorod Hybrids with Efficient Photo-Induced Charge Transfer

Nanoscale Research Letters ◽

10.1186/s11671-021-03504-3 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Chunzheng Lv ◽

Lirong He ◽

Jiahong Tang ◽

Feng Yang ◽

Chuhong Zhang

Keyword(s):

Charge Transfer ◽

Electric Field ◽

Self Assembly ◽

Molecular Level ◽

Surface Photovoltage ◽

Zno Nanorod ◽

In Situ Reaction ◽

Perylene Bisimide ◽

Induced Charge

AbstractAs an important photoconductive hybrid material, perylene/ZnO has attracted tremendous attention for photovoltaic-related applications, but generally faces a great challenge to design molecular level dispersed perylenes/ZnO nanohybrids due to easy phase separation between perylenes and ZnO nanocrystals. In this work, we reported an in-situ reaction method to prepare molecular level dispersed H-aggregates of perylene bisimide/ZnO nanorod hybrids. Surface photovoltage and electric field-induced surface photovoltage spectrum show that the photovoltage intensities of nanorod hybrids increased dramatically for 100 times compared with that of pristine perylene bisimide. The enhancement of photovoltage intensities resulting from two aspects: (1) the photo-generated electrons transfer from perylene bisimide to ZnO nanorod due to the electric field formed on the interface of perylene bisimide/ZnO; (2) the H-aggregates of perylene bisimide in ZnO nanorod composites, which is beneficial for photo-generated charge separation and transportation. The introduction of ordered self-assembly thiol-functionalized perylene-3,4,9,10-tetracarboxylic diimide (T-PTCDI)/ ZnO nanorod composites induces a significant improvement in incident photo-to-electron conversion efficiency. This work provides a novel mentality to boost photo-induced charge transfer efficiency, which brings new inspiration for the preparation of the highly efficient solar cell.

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