Progress in food packaging applications of biopolymer-nanometal composites - A comprehensive review.

Eco-friendly nanotechnology-enabled biopolymers are one of the novel concepts of packaging materials to substitute traditional synthetic polymers and their composites. This article succinctly reviews the recent developments of introducing additional functionalities to biopolymers using metal and metal oxide nanoparticles. The functionality of metal nanoparticles such as silver, zinc oxide, titanium dioxide, copper oxide, gold, and magnesium oxide, as food packaging materials were discussed. The addition of nanoparticles in biopolymers improves mechanical properties, gas barrier properties, durability, temperature stability, moisture stability, antimicrobial activity, antioxidant property, and UV absorbance and can prevent the presence of ethylene and oxygen, hence extending the shelf life of foodstuffs. Other than this, the functional activity of these biopolymer composite films helps them to act like smart or intelligent packaging. The selection of metal nanoparticles, particle migration, toxicological effect, and potential future scope in the food packaging industry are also reviewed.

MXene-Based Elastomer Mimetic Stretchable Sensors: Design, Properties, and Applications.

Flexible sensors based on MXene-polymer composites are highly prospective for next-generation wearable electronics used in human-machine interfaces. One of the motivating factors behind the progress of flexible sensors is the steady arrival of new conductive materials. MXenes, a new family of 2D nanomaterials, have been drawing attention since the last decade due to their high electronic conductivity, processability, mechanical robustness and chemical tunability. In this review, we encompass the fabrication of MXene-based polymeric nanocomposites, their structure-property relationship, and applications in the flexible sensor domain. Moreover, our discussion is not only limited to sensor design, their mechanism, and various modes of sensing platform, but also their future perspective and market throughout the world. With our article, we intend to fortify the bond between flexible matrices and MXenes thus promoting the swift advancement of flexible MXene-sensors for wearable technologies.

Fabrication and Applications of Magnetic Polymer Composites for Soft Robotics.

The emergence of magnetic polymer composites has had a transformative impact on the field of soft robotics. This overview will examine the various methods by which innovative materials can be synthesized and utilized. The advancement of soft robotic systems has been significantly enhanced by the utilization of magnetic polymer composites, which amalgamate the pliability of polymers with the reactivity of magnetic materials. This study extensively examines the production methodologies involved in dispersing magnetic particles within polymer matrices and controlling their spatial distribution. The objective is to gain insights into the strategies required to attain the desired mechanical and magnetic properties. Additionally, this study delves into the potential applications of these composites in the field of soft robotics, encompassing various devices such as soft actuators, grippers, and wearable gadgets. The study emphasizes the transformative capabilities of magnetic polymer composites, which offer a novel framework for the advancement of biocompatible, versatile soft robotic systems that utilize magnetic actuation.

Capra cartilage-derived peptide delivery via carbon nano-dots for cartilage regeneration.

Targeted delivery of site-specific therapeutic agents is an effective strategy for osteoarthritis treatment. The lack of blood vessels in cartilage makes it difficult to deliver therapeutic agents like peptides to the defect area. Therefore, nucleus-targeting zwitterionic carbon nano-dots (CDs) have immense potential as a delivery vehicle for effective peptide delivery to the cytoplasm as well as nucleus. In the present study, nucleus-targeting zwitterionic CDs have been synthesized as delivery vehicle for peptides while also working as nano-agents towards optical monitoring of cartilage healing. The functional groups of zwitterion CDs were introduced by a single-step microwave assisted oxidation procedure followed by COL II peptide conjugation derived from Capra auricular cartilage through NHS/EDC coupling. The peptide-conjugated CDs (PCDs) allows cytoplasmic uptake within a short period of time (∼30 m) followed by translocation to nucleus after ∼24 h. Moreover, multicolor fluorescence of PCDs improves (blue, green, and read channel) its sensitivity as an optical code providing a compelling solution towards enhanced non-invasive tracking system with multifunctional properties. The PCDs-based delivery system developed in this study has exhibited superior ability to induce ex-vivo chondrogenic differentiation of ADMSCs as compared to bare CDs. For assessment of cartilage regeneration potential, pluronic F-127 based PCDs hydrogel was injected to rabbit auricular cartilage defects and potential healing was observed after 60 days. Therefore, the results confirm that PCDs could be an ideal alternate for multimodal therapeutic agents.

Revolutionizing Food Safety with Quantum Dot-Polymer Nanocomposites: From Monitoring to Sensing Applications.

The present review article investigates the prospective utilisation of quantum dot-polymer nanocomposites in the context of ensuring food safety. The text pertains to the advancement of nanocomposites, encompassing their distinctive optical and electrical characteristics, and their prospective to transform the detection and perception of food safety risks. The article explores diverse methodologies for producing nanocomposites and underscores their potential utility in identifying impurities, microorganisms, and harmful substances in food. The article provides an overview of the challenges and limitations associated with the utilisation of nanocomposites in food safety applications, encompassing concerns regarding toxicity and the necessity for standardised protocols. The review article presents a comprehensive examination of the present research status in this area and underscores the potential of quantum dots-polymer nanocomposites in transforming food safety monitoring and sensing.

Bioimaging Probes Based on Magneto-Fluorescent Nanoparticles.

Novel nanomaterials are of interest in biology, medicine, and imaging applications. Multimodal fluorescent-magnetic nanoparticles demand special attention because they have the potential to be employed as diagnostic and medication-delivery tools, which, in turn, might make it easier to diagnose and treat cancer, as well as a wide variety of other disorders. The most recent advancements in the development of magneto-fluorescent nanocomposites and their applications in the biomedical field are the primary focus of this review. We describe the most current developments in synthetic methodologies and methods for the fabrication of magneto-fluorescent nanocomposites. The primary applications of multimodal magneto-fluorescent nanoparticles in biomedicine, including biological imaging, cancer treatment, and drug administration, are covered in this article, and an overview of the future possibilities for these technologies is provided.

Naturally Derived Carbon Dots In Situ Confined Self-Healing and Breathable Hydrogel Monolith for Anomalous Diffusion-Driven Phytomedicine Release.

Fluorescent nanocarbons are well-proficient nanomaterials because of their optical properties and surface engineering. Herein, Apium graveolens-derived carbon dots (ACDs) have been synthesized by a one-step hydrothermal process without using any surplus vigorous chemicals or ligands. ACDs were captured via an in situ gelation reaction to form a semi-interpenetrating polymer network system showing mechanical robustness, fluorescent behavior, and natural adhesivity. ACDs-reinforced hydrogels were tested against robust uniaxial stress, repeated mechanical stretching, thixotropy, low creep, and fast strain recovery, confirming their elastomeric sustainability. Moreover, the room-temperature self-healing behavior was observed for the ACDs-reinforced hydrogels, with a healing efficacy of more than 45%. Water imbibition through hydrogel surfaces was digitally monitored via "breathing" and "accelerated breathing" behaviors. The phytomedicine release from the hydrogels was tuned by the ACDs' microstructure regulatory activity, resulting in better control of the diffusion rate compared to conventional chemical hydrogels. Finally, the phytomedicine-loaded hydrogels were found to be excellent bactericidal materials eradicating more than 85% of Gram-positive and -negative bacteria. The delayed network rupturing, superstretchability, fluorescent self-healing, controlled release, and antibacterial behavior could make this material an excellent alternative to soft biomaterials and soft robotics.

Mussel-Inspired Polynorepinephrine/MXene-Based Magnetic Nanohybrid for Electromagnetic Interference Shielding in X-Band and Strain-Sensing Performance.

The current work delivers preparation of MXene-based magnetic nanohybrid coating for flexible electronic applications. Herein, we report carbon dot-triggered photopolymerized polynorepinepherene (PNE)-coated MXene and iron oxide hybrid deposited on the cellulose microporous membrane via a vacuum-assisted filtration strategy. The surface morphologies have been monitored by scanning electron microscopy analysis, and the coating thickness was evaluated by the gallium-ion-based focused ion beam method. Coated membranes have been tested against uniaxial tensile stretching and assessed by their fracture edges in order to assure flexibility and mechanical strength. Strain sensors and electromagnetic interference (EMI) shielding have both been tested on the material because of its electrical conductivity. The bending strain sensitivity has been stringent because of their fast 'rupture and reform' percolation network formation on the coated surface. Increased mechanical strength, solvent tolerance, cyclic deformation tolerance, and EMI shielding performance were achieved by decreasing interstitial membrane porosity. Considering a possible application, the membrane also has been tested against simulated static and dynamic water flow conditions that could infer its excellent robustness which also has been confirmed by elemental analysis via ICP-MS. Thus, as of nurturing the works of the literature, it could be believed that the developed material will be an ideal alternative of flexible lightweight cellulose for versatile electronic applications.

Design of Magnetic Hydrogels for Hyperthermia and Drug Delivery.

Hydrogels are spatially organized hydrophilic polymeric systems that exhibit unique features in hydrated conditions. Among the hydrogel family, composite hydrogels are a special class that are defined as filler-containing systems with some tailor-made properties. The composite hydrogel family includes magnetic-nanoparticle-integrated hydrogels. Magnetic hydrogels (MHGs) show magneto-responsiveness, which is observed when they are placed in a magnetic field (static or oscillating). Because of their tunable porosity and internal morphology they can be used in several biomedical applications, especially diffusion-related smart devices. External stimuli may influence physical and chemical changes in these hydrogels, particularly in terms of volume and shape morphing. One of the most significant external stimuli for hydrogels is a magnetic field. This review embraces a brief overview of the fabrication of MHGs and two of their usages in the biomedical area: drug delivery and hyperthermia-based anti-cancer activity. As for the saturation magnetization imposed on composite MHGs, they are easily heated in the presence of an alternating magnetic field and the temperature increment is dependent on the magnetic nanoparticle concentration and exposure time. Herein, we also discuss the mode of different therapies based on non-contact hyperthermia heating.

Carbon-Dots-Initiated Photopolymerization: An In Situ Synthetic Approach for MXene/Poly(norepinephrine)/Copper Hybrid and its Application for Mitigating Water Pollution.

The current work presents a facile and green synthesis of carbon quantum dots (C-dots), which could serve as initiators for polymerization. Herein, C-dots have been synthesized from an easily available green herb, dill leaves, by a single-step hydrothermal method. These C-dots were efficiently utilized as initiators for the photopolymerization of the polymer poly(norepinephrine) (PNE) for the first time. The photopolymerization is discussed by a factorial design, and the optimized synthesis conditions were evaluated by a third-order regression model of three reaction parameters: monomer concentration, C-dots concentration, and UV exposure time. The sign convention of the factorial design mode indicated that monomer concentration and time of exposure are the most important factors for polymerization. The photopolymerized poly(norepinephrine) was extensively studied using Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), mass spectra, scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurement, and thermogravimetric analysis (TGA). UV-assisted deposition of PNE on six different types of substrates was performed, and their water contact angle and surface morphology were studied to evaluate the coating. This UV-triggered polymerization technique was further applied to fabricate sandwich-like composite catalyst MXene/poly(norepinephrine)/copper nanoparticles. This catalyst displayed good performance in the reduction of 4-NP (4-nitrophenol) at ambient temperature, and the first-order rate constant of the catalysis was 9.39 × 10-3 s-1. The reusability of the catalyst was evaluated in terms of the conversion factor. After 10 catalytic cycles, the conversion to catalyze 4-NP was still greater than 91%. The catalytic performance was also evaluated in the continuous flow condition through a membrane, fabricated from a cellulose filter paper coated with MXene/poly(norepinephrine)/copper nanoparticles. This composite catalyst not only offers a practical mode for the catalytic reaction of MXene-based materials but also lays down the foundation for the development of new catalysts.

Immobilization of Heteroatom-Doped Carbon Dots onto Nonpolar Plastics for Antifogging, Antioxidant, and Food Monitoring Applications.

This work presents the facile synthesis of heteroatom-doped fluorescent carbon quantum dots (C-dots), which could serve as an antioxidant. Herein, nitrogen, phosphorous, and sulfur codoped carbon dots (NPSC-dots) have been synthesized by a single-step hydrothermal strategy. Owing to the radical scavenging activity of the NPSC-dots, they were tested against several methods as well as in practical applications. The antioxidant ability of the NPSC-dots was efficiently utilized on plastic films by coating with these NPSC-dots. For the very first time, NPSC-dots were immobilized onto nonpolar plastic films (polypropylene) via photochemical covalent grafting to extend the shelf life of food items or storage without affecting the quality of plastic films. The NPSC-dot-coated PP film with negligible deterioration of transparency was extensively studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), contact angle measurement, and thermogravimetric analysis (TGA). The fluorescent character, antioxidant ability, and durability under different solvent systems of the coated film were examined. Also, the coated films were extensively and rigorously evaluated against simulated drastic environmental conditions to ensure the durability and antifogging application.

Tailor made magnetic nanolights: fabrication to cancer theranostics applications.

Nanoparticles having magnetic and fluorescent properties could be considered as a gift to materials scientists due to their unique magneto-optical qualities. Multiple component particles can overcome challenges related with a single component and unveil bifunctional/multifunctional features that can enlarge their applications in diagnostic imaging agents and therapeutic delivery vehicles. Bifunctional nanoparticles that have both luminescent and magnetic features are termed as magnetic nanolights. Herein, we present recent progress of magneto-fluorescent nanoparticles (quantum dots based magnetic nanoparticles, Janus particles, and heterocrystalline fluorescent magnetic materials), comprehensively describing fabrication strategies, types, and biomedical applications. In this review, our aim is not only to encompass the preparation strategies of these special types of magneto-fluorescent nanomaterials but also their extensive applications in bioimaging techniques, cancer therapy (targeted and hyperthermic), and sustained release of active agents (drugs, proteins, antibodies, hormones, enzymes, growth factors).

Microwave-Synthesized Polysaccharide-Derived Carbon Dots as Therapeutic Cargoes and Toughening Agents for Elastomeric Gels.

Fluorescent carbon dots (CDs) play a versatile role in materials science. Herein, we have developed alginate-derived nitrogen-doped CDs as a drug carrier and a toughening agent for hydrogels by a microwave-assisted method. In the first phase of work, we carried out covalent conjugation of the drug onto the CD surface for controlled delivery of drug molecules, and in the second phase of work, we demonstrated how CDs could act as a toughening agent as well as a viscosity modifier for poly(acrylic acid-co-methacrylamide) copolymer hydrogels. The hydrogels were evaluated by Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, and solid-state nuclear magnetic resonance. The hybrid hydrogels have been tested to be mechanically robust with extraordinary stretchability (∼1200% elongation at break), recoverable to the original position (low permanent set), tunable water uptake, and thixotropic character in dynamic stress. The crosslinked structure has been evaluated through void calculation revealing gradual densification of the network with increasing CD content. Exceptional gel strength (ratio of elastic modulus to loss modulus; G'/G″) has been achieved from analogous crosslinking made by CDs. The delayed network rupturing and superstretchability could make this material a good choice for soft biomaterials and soft robotics.

Review: Remotely controlled magneto-regulation of therapeutics from magnetoelastic gel matrices.

Surface active magnetic nanoparticles especially superparamagnetic iron oxides are already occupying a major domain in medical therapeutics. Arresting of these magnetic nanoparticles into polymer hydrogel is a spatial assembly of nanoparticles that serves the precise delivery of drug molecules. Magnetic hydrogels are very less cultured area still in the biomedical field. This review embraces how the external magnetic field (either static or oscillating) affects the payload release from the hydrogel matrix and their magneto-regulative deformation. Besides these, we also discussed how the ferrosponge and biphasic ferrogel based scaffold type systems impact over the release kinetics and tunability of drug release behaviours.

Applications of N-Doped Carbon Dots as Antimicrobial Agents, Antibiotic Carriers, and Selective Fluorescent Probes for Nitro Explosives.

The synthesis of nitrogen-doped carbon dots (N@CDs) was accomplished by a hydrothermal process using meta- phenylenediamine as a source of carbon and nitrogen. As prepared N@CDs exhibited bright blue color fluorescence emission (λex = 340 nm and λem = 420 nm) with a quantum yield of 12%. Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were eradicated by N@CDs with a minimum inhibition concentration (MIC) of 1 and 0.75 mg/mL, respectively. The N@CDs were also proven as nanovesicles for drug molecules where the drug release displayed a sustained time-dependent profile at the physiological condition. The release of ciprofloxacin as a model drug was governed by the Korsmeyer-Peppas model, indicating ∼60% of its release from the N@CD conjugated drug system at the physiological pH. Selective analysis of trinitrophenol (TNP), a popular explosive, was achieved by fluorescence quenching of N@CDs, compared favorably with other nitrophenols. An estimated detection limit of TNP was 2.45 µM with a linear response spanning from 1 to 75 µM.

Acoustic cavitation assisted destratified clay tactoid reinforced in situ elastomer-mimetic semi-IPN hydrogel for catalytic and bactericidal application.

Ultrasonicaion is non-chemical process where acoustic waves have been targeted to aqueous medium dispersed precursor materials. In situ synthesis of silver nanoparticles anchored in hydrogel matrix has been opted via ~20 kHz frequency assisted (bath sonication) synthesis having the ultrasonication power intensity (UPI) of ~106 J/m2. Power intensity is inversely proportional to the surface area of the clay tactoids. The hydrogel have been prepared by in situ 20 kHz assisted sonochemical destratification of laponite clay tactoids which could be terminologically stated as 'top-down method'. Silver nanoparticles (AgNPs) have been deposited in the surfaces of the porous matrix of hydrogel via 'soak and irradiate' method. Soaking of silver ions into the gel matrix is welcomed due to their efficient stabilization and fast transformation towards AgNPs. AgNPs played the key role in catalytic reduction and bactericidal activity. Moreover, the prepared hydrogel has enough robust to withstand cyclic stress, uniaxial stress and oscillatory stress which have been extensively justified by the physico-mechanical characterizations. The gel supported catalyst showed first order reaction kinetics and less time consuming period during reduction of 4-nitrophenol as a model pollutant.

Converting waste Allium sativum peel to nitrogen and sulphur co-doped photoluminescence carbon dots for solar conversion, cell labeling, and photobleaching diligences: A path from discarded waste to value-added products.

Proper waste utilization in order to promote value added product is a promising scientific practice in recent era. Inspiring from the recurring trend, we propose a single step oxidative pyrolysis derived fluorescent carbon dots (C-dots) from Allium sativum peel, which is a natural, nontoxic, and waste raw material. Because of its excellent optical properties, and photostability this C-dots have been used in versatile area of applications. Due to its immediate water dispersing character, C-dots reinforced Poly(acrylic acid) (PAA) films revealed improvement in uniaxial stretching behavior and can be used as transparent sunlight conversion film. The nanocomposite film has been tested against rigorous simulated sunlight which proved almost identical sunlight conversion behavior with no photo-bleachable character which is definitely added an extra quality of transparent polymer films. Moreover, the C-dots dispersion has been used as in vitro biomarker for living cells owing to its ease in solubility, biocompatibility, non-cytotoxicity and bright fluorescence even in subcutaneous environment. For this case, adipose derived mesenchymal stem cells (ADMSCs) have been chosen and injected to rabbit ear skin to perform two-photon imaging experiment. The present work opens a new avenue towards the large-scale synthesis of bio-waste based fluorescent C-dots, paving the way for their versatile applications.

Isolation and mass spectrometry based hydroxyproline mapping of type II collagen derived from Capra hircus ear cartilage.

Collagen II (COLII), the most abundant protein in vertebrates, helps maintain the structural and functional integrity of cartilage. Delivery of COLII from animal sources could improve cartilage regeneration therapies. Here we show that COLII can be purified from the Capra ear cartilage, a commonly available bio-waste product, with a high yield. MALDI-MS/MS analysis evidenced post-translational modifications of the signature triplet, Glycine-Proline-Hydroxyproline (G-P-Hyp), in alpha chain of isolated COLII (COLIIA1). Additionally, thirty-two peptides containing 59 Hyp residues and a few G-X-Y triplets with positional alterations of Hyp in COLIIA1 are also identified. Furthermore, we show that an injectable hydrogel formulation containing the isolated COLII facilitates chondrogenic differentiation towards cartilage regeneration. These findings show that COLII can be isolated from Capra ear cartilage and that positional alteration of Hyp in its structural motif, as detected by newly developed mass spectrometric method, might be an early marker of cartilage disorder.

Biocompatible carbon dots derived from κ-carrageenan and phenyl boronic acid for dual modality sensing platform of sugar and its anti-diabetic drug release behavior.

Detection of sugar by enzymatic assay has been suffering from costly, time-taking, instable and denaturation of glucose oxidase. Recently, chemosensors that have affinity towards boronate became the hot topic in the domain of monosaccharide detection. In this work, a novel strategy was addressed to fabricate carbon dots (C-dots) from linear sulfated polysaccharides κ- carrageenan and phenyl boronic acid for nonenzymatic monosaccharide (glucose) detection. The boronic acid group anchored C-dots surface can form assembly by covalently bonded with the cis-diol moiety of the glucose which caused fluorescence quenching of the C-dots. The inert surface nature of the luminescent C-dots enables them to sense as low as 1.7 µM glucose without the interference of other biomolecules. The proposed sensing system was successfully applied for assay of glucose in blood serum. Interestingly, these C-dots were used as a nano vehicle for delivery of anti-diabetic drug Metformin. Good biocompatibility results were found with MTT and hemolysis assay. Owing to its simplicity and effectiveness, the as-prepared C-dots offered great promise for blood sugar diagnosis and treatment.

Polysaccharide and poly(methacrylic acid) based biodegradable elastomeric biocompatible semi-IPN hydrogel for controlled drug delivery.

Nanoparticles embedded semi-interpenetrating (semi-IPNs) polymeric hydrogels with enhanced mechanical toughness and biocompatibility could have splendid biomedical acceptance. Here we propose poly(methacrylic acid) grafted polysaccharide based semi-IPNs filled with nanoclay via in situ Michael type reaction associated with covalent crosslinking with N,N-methylenebisacrylamide (MBA). The effect of nanoclay in the semi-IPN hydrogel has been investigated which showed significant improvement of mechanical robustness. Meanwhile, the hydrogels showed reversible ductility up to 70% in response to cyclic loading-unloading cycle which is an obvious phenomenon of rubber-like elasticity. The synthesized semi-IPN hydrogel show biodegradability and non-cytotoxic nature against human cells. The live-dead assay showed that the prepared hydrogel is a viable platform for cell growth without causing severe cell death. The in vitro drug release study in psychological pH (pH = 7.4) reveals that the controlled drug release phenomena can be tuned by simulating the environment pH. Such features in a single hydrogel assembly can propose this as high performance; biodegradable and non-cytotoxic 3D scaffold based promising biomaterial for tissue engineering.