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The technology of food packaging is responding to significant market dynamics such as the rapid growth in e-commerce and preservation of fresh food, a sector that accounts for over 40% of plastic waste. Further, mandates for sustainability and recent changes in national governmental policies and regulations that include banning single-use plastic products as observed in sweeping reforms in Europe, Asia, and several US States are forcing industries and consumers to find alternative solutions. This review highlights an ongoing shift of barrier coatings from traditional synthetic polymers to sustainable breakthrough materials for paper-based packaging and films. Advantages, challenges and adapting feasibility of these materials are described, highlighting the implications of selecting different materials and processing options. A brief description on progress in methods of coating technologies is also included. Finally, the end fate of the barrier materials is classified depending on the packaging type, coating materials used and sorting facility availability. Different types of coatings, such as water-based biopolymers, due to their greater environmental compatibility, are making inroads into more traditional petroleum-based wax and plastic laminate paperboard products for fresh food bakery, frozen food, and take-out containers applications. In addition, nano-biocomposites have been studied at an accelerating pace for developing active and smart packaging. Based on the momentum of recent developments, a strong pace of continuing developments in the field can be expected. [Display omitted] • Top trends in food packaging are driven by sustainability, e-commerce, and the end fate of the materials. • Recent developments in bio-based materials have the potential of replacing petro-based polymers. • High speed and specialized coating methods have emerged in the past few years for food packaging development. • Businesses are focused on the recycling of synthetic and biopolymers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Developed Poly(N-Isopropylacrylamide)-Cellulose Nanocrystal hydrogel films. • Achieved unique thermo-responsivity and tunable optical performance. • Developed a hybrid materials system to modulate LCST and moisture content for thermo-responsivity and optical tunability. • Demonstrated a ∼ 15 °C reduction of the LCST relative to pure PNIPAm hydrogel films. • Below the LCST, PNIPAm/CNC hydrogel films exhibit transparency or semi-transparency. Abstract A hybrid materials system to modulate lower critical solution temperature (LCST) and moisture content for thermo-responsivity and optical tunability was strategically developed by incorporating cellulose nanocrystals (CNCs) into a poly(N -isopropylacrylamide) (PNIPAm) hydrogel matrix. The PNIPAm/CNC hydrogel films exhibit tunable optical properties and wavelength bandpass selectivity as characterized by PROBE Spectroscopy and Dynamic Light Scattering (DLS). Importantly, the micro/nano structures of the PNIPAm/CNC hydrogel films were completely different when dried below and above the LCST. Below the LCST, PNIPAm/CNC hydrogel films exhibit transparency or semi-transparency due to the uniform bonding of hydrophilic PNIPAm and CNC through hydrogen bonds. Above the LCST, the hydrogel films engage in both hydrophobic PNIPAm and hydrophilic CNC interactions due to changes in PNIPAm conformation which lead to light scattering effects and hence opacity. Furthermore, the incorporation of CNC induces a ∼ 15 °C reduction of the LCST relative to pure PNIPAm hydrogel films. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A new pathway for sustainable packaging materials was engineered by formulating multilayer CNF/CNC barrier coatings. • CNF and CNC synergistically enabled high oil and grease resistance (a kit rating of 11) comparable to fluorochemicals. • A significant reduction in oxygen transmission rate was demonstrated (∼by a factor of about 260) compared to uncoated paper. • Sustainable biomaterials are relevant to society's ongoing efforts to improve health, safety, and environmental stewardship. Abstract Cellulose derivatives such as cellulose nanofibers (CNF) and cellulose nanocrystals (CNC) have enormous potential to reduce or replace petroleum and fluorochemicals for food and other packaging applications. CNFs have been studied for their excellent oxygen and gas barrier properties; however, their performance rapidly decreases in the presence of moisture and higher humidity. CNCs are less sensitive to moisture due to their highly crystalline nature; however, coatings and films made of CNCs are much more prone to fracture due to their high brittleness. Our work demonstrates a unique composite barrier coating system of CNF and CNC that synergistically enables oil and grease resistance (a kit rating of 11) comparable to fluorochemicals. It also demonstrates a significant increase in air resistance (∼by a factor of about 300), and a reduction in oxygen transmission rate (∼by a factor of about 260) compared to uncoated paper. The improvements in oil and gas barrier properties were evaluated with respect to the molecular, chemical, and structural properties of the developed coatings. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: Congenital pouch colon (CPC) associated with anorectal malformation (ARM) is most commonly reported from Northern India. So far, no physiologic study comparing the detailed contractile status of CPC with non-CPC conditions are available. The present article deals with the contractile study and histopathologic observations in CPC, which may be useful for better surgical management. Methods: Freshly excised 12 neonatal CPC and similar number of non-CPC (control) specimens were transferred to ice-cold (4°C-6°C) Krebs-Ringer solution bubbled with 100% oxygen. Longitudinally prepared 2 to 4 colonic strips were obtained from central part of each specimen and subjected to the contraction recording after exposure to cumulative concentrations of acetylcholine (ACh) and histamine. Acetylcholine-induced contractions were evaluated after application of atropine (muscarinic blocker), and histaminergic contractions were recorded after pheniramine (H1 blocker), lignocaine (neuronal blocker), and atropine. Histopathologic observations were made by using H&E and Masson trichrome stains. Results: Control specimens showed spontaneous contractions, but CPC strips did not. Both control and CPC responded to ACh and histamine. The response to histamine was greater (P < .05) in CPC as compared to control, whereas the response to ACh was more (P < .05) in control. In CPC, response of histamine (100 μmol/L) was blocked by pheniramine (0.32 mmol/L) and lignocaine (4 mmol/L) by 97% and 80%, respectively, and enhanced by 57% after preapplication of atropine (10 μmol/L). Acetylcholine (100 μmol/L)-induced contractions were attenuated (86%) in presence of atropine. Histopathologic examination showed fewer mature ganglion cells with various changes in muscle layers including fibrosis, disruption, hypertrophy, atrophy, and constriction bands. Conclusion: Congenital pouch colon associated with ARM lacks normal spontaneous contractions but retains ACh and histamine-induced contractility. In view of the functional and histologic abnormalities, we propose that CPC associated with ARM is an abnormally functional and developed tissue. Therefore, resection of the pouch should be considered for better functional outcome of the remaining bowel. [Copyright &y& Elsevier]

[Display omitted] • Extraction of lignin-containing cellulose nanofibers (LCNF) from hemp hurds waste. • Development of LCNF coatings/films with reduced polarity and low hydrophilicity. • Elucidation of the role of lignin content and distribution on barrier properties. • Significantly higher water contact angle with LCNF coatings and films. • LCNF-based coatings/films can contribute to a circular economy and sustainability. Residual hemp (Cannabis sativa) hurd fibers obtained from hydrothermal, carbonate, and kraft treatments were the resources used to obtain lignocellulosic nanofibers (LCNF) by using an ultra-fine friction grinder. The morphological, crystallinity, and chemical characteristics of the nanocellulose films were carried out using SEM, XRD, EDX and ToF-SIMS. Water barrier properties of the same were measured in terms of water contact angle, water vapor permeability (WVP) and water absorption. The barrier properties were found to be dependent not only on the lignin content and lignin distribution, but also on the film density and porous structure. LCNF films and coatings showed much higher water contact angle (WCA) (80°-102°) than films produced from the bleached CNF. WVP was found to be more dependent on the density of films than lignin content. Overall, LCNF-based films and coatings derived from hemp hurd residual fibers can contribute to a circular economy and sustainability. [ABSTRACT FROM AUTHOR]

• Tunable poly(N-Isopropylacrylamide)-cellulose nanofibrils hydrogel films. • Fabrication using inverted SLA 3D printing to provide a new manufacturing platform. • Switchable bio-adhesion to bacteria depending on the CNF content and distribution. • Unique thermo-responsivity and tunable optical performance. • Modulation of LCST (∼ 8 °C reduction) relative to pure PNIPAm hydrogel films. A hybrid poly(N-isopropylacrylamide) (PNIPAm)/cellulose nanofibrils (CNFs) hydrogel composite was fabricated by inverted stereolithography 3D printing to provide a new platform for regulating lower critical solution temperature (LCST) properties and thus tuning optical and bioadhesive properties. The phenomena of interest in the as-printed PNIPAm/CNF hydrogels may be attributed to the fiber-reinforced composite system between crosslinked PNIPAm and CNFs. The optical tunability was found to be correlated to the micro/nano structures of the PNIPAm/CNF hydrogel films. It was found that PNIPAm/CNF hydrogels exhibit switchable bioadhesivity to bacteria in response to CNF distribution in the hydrogels. After 2.0 wt% CNF was incorporated, it was found that a remarkable 8°C reduction of the LCST was achieved relative to PNIPAm hydrogel crosslinked by TEGDMA without CNF. The prepared PNIPAm/CNF hydrogels possessed highly reversible optical, bioadhesion, and thermal performance, making them suitable to be used as durable temperature-sensitive sensors and functional biomedical devices. [ABSTRACT FROM AUTHOR]