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Due to its high toxicity, Pb2+ pollution is a serious threat for human health and environments. However, in situ real-time detection of Pb2+ pollution is difficult and laboratory instruments are usually required. Then, the possibility to monitor water quality without laboratory instruments could lead to the extensive assessment of polluted water so...
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... particular, sodium alginate, beside its large solubility in water, undergoes a fast physical cross-linking when in contact with bivalent and trivalent ions such as Pb 2+ according to the so-called "egg-box" model [80][81][82][83]. The SA structure and the cross-linking egg-box model are represented in Figure 1. There, the guluronic acid residues of the polymer are directly coordinated by Pb 2+ to form a water insoluble, permanent 3D-network [83][84][85][86]. ...
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Water pollution is one of the major environmental problems facing developing countries all over the planet. The mathematical model for soluble and insoluble water pollutants has been formulated in light of ordinary differential equations. Sensitivity analysis is carried out to examine parameter values that are associated with the reproduction numbe...
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... The recent advances in nanotechnology have opened the way to the design and fabrication of new materials for a broad variety of applications including the biomedical [1] and pharmaceutical industries [2], the textile [3] and the agriculture sectors [4], food packaging products [5], sensing materials [6][7][8], and wastewater remediation treatments [9]. In this sense, plasmonic nanoparticles are characterized by an increasing deal of interest owing to their unique physical and chemical properties [10]. ...
Poly(vinyl alcohol) nanofibrous mats containing ad hoc synthesized gold nanostructures were prepared via a single-step electrospinning procedure and investigated as a novel composite platform with several potential applications. Specifically, the effect of differently shaped and sized gold nanostructures on the resulting mat physical-chemical properties was investigated. In detail, nearly spherical nanoparticles and nanorods were first synthesized through a chemical reduction of gold precursors in water by using (hexadecyl)trimethylammonium bromide as the stabilizing agent. These nanostructures were then dispersed in poly(vinyl alcohol) aqueous solutions to prepare nanofibrous mats, which were then stabilized via a humble thermal treatment able to enhance their thermal stability and water resistance. Remarkably, the nanostructure type was proven to influence the mesh morphology, with the small spherical nanoparticles and the large nanorods leading to thinner well defined or bigger defect-rich nanofibers, respectively. Finally, the good mechanical properties shown by the prepared composite mats suggest their ease of handleability thereby opening new perspective applications.
... Nevertheless, when in contact with high moisture environments typical of food packages, these redox dyes may be released from the water-insoluble polymer matrix in which they are embedded and diffuse into the packaging, hence posing health concerns. In this sense, the cation-binding capability of alginate, a polysaccharide extracted from brown algae and widely exploited in biomedical, pharmaceutical, wastewater remediation, and food applications [78][79][80][81][82][83], has been used to prevent dye leaching [84]. brown algae and widely exploited in biomedical, pharmaceutical, wastewater remediation, and food applications [78][79][80][81][82][83], has been used to prevent dye leaching [84]. ...
... In this sense, the cation-binding capability of alginate, a polysaccharide extracted from brown algae and widely exploited in biomedical, pharmaceutical, wastewater remediation, and food applications [78][79][80][81][82][83], has been used to prevent dye leaching [84]. brown algae and widely exploited in biomedical, pharmaceutical, wastewater remediation, and food applications [78][79][80][81][82][83], has been used to prevent dye leaching [84]. ...
Food packaging encompasses the topical role of preserving food, hence, extending the shelf-life, while ensuring the highest quality and safety along the production chain as well as during storage. Intelligent food packaging further develops the functions of traditional packages by introducing the capability of continuously monitoring food quality during the whole chain to assess and reduce the insurgence of food-borne disease and food waste. To this purpose, several sensing systems based on different food quality indicators have been proposed in recent years, but commercial applications remain a challenge. This review provides a critical summary of responsive systems employed in the real-time monitoring of food quality and preservation state. First, food quality indicators are briefly presented, and subsequently, their exploitation to fabricate intelligent packaging based on responsive materials is discussed. Finally, current challenges and future trends are reviewed to highlight the importance of concentrating efforts on developing new functional solutions.
... Polysaccharides are a class of naturally occurring polymers broadly employed in several application fields owing to their unique properties such as biodegradability, biocompatibility, ease of functionalization, responsivity to external stimuli, low cost, and reduced environmental impact [1][2][3][4][5][6][7][8][9]. For instance, in the last decade several polysaccharidebased products have been developed for biomedical [10], pharmaceutical [11], food packaging [12], food additive [13], environmental [14,15], sensing [16], and textile applications [17]. Among such materials, sodium alginate is one of the most promising and investigated. ...
Alginate-based electrospun nanofibers prepared via electrospinning technique represent a class of materials with promising applications in the biomedical and pharmaceutical industries. However, to date, the effect of alginate molecular mass and block composition on the biological response of such systems remains to some extent unclear. As such, in the present work, three alginates (i.e., M.pyr, L.hyp, A.nod) with different molecular features are employed to prepare nanofibers whose ability to promote cell adhesion is explored by using both skin and bone cell lines. Initially, a preliminary investigation of the raw materials is carried out via rheological and zeta-potential measurements to determine the different grade of polyelectrolyte behaviour of the alginate samples. Specifically, both the molecular mass and block composition are found to be important factors affecting the alginate response, with long chains and a predominance of guluronic moieties leading to a marked polyelectrolyte nature (i.e., lower dependence of the solution viscosity upon the polymer concentration). Subsequently, physically crosslinked alginate nanofibrous mats are first morphologically characterized via both scanning electron and atomic force microscopy, which show a homogenous and defect-free structure, and their biological response is then evaluated. Noticeably, fibroblast and keratinocyte cell lines do not show significant differences in terms of cell adhesion on the three mats (i.e., 30-40 % and 10-20 % with respect to the seeded cells, respectively), with the formers presenting a greater affinity toward the alginate-based nanofibers. Conversely, both the investigated osteoblast cells are characterized by a distinct behaviour depending on the alginate type. Specifically, polysaccharide samples with an evident polyelectrolyte nature are found to better promote cell viability (i.e., cell adhesion in the range 15-36 % with respect to seeded cells) compared to the ones displaying a nearly neutral behaviour (i.e., cell adhesion in the range 5-25 % with respect to seeded cells). Therefore, the obtained results, despite being preliminary, suggest that the alginate type (i.e., molecular structure properties) may play a topical role in conditioning the efficiency of healing patches for bone reparation, but it has a negligible effect in the case of skin regeneration.
... Polysaccharides are a class of naturally occurring polymers broadly employed in several application fields owing to their unique properties such as biodegradability, biocompatibility, ease of functionalization, responsivity to external stimuli, low cost, and reduced environmental impact [1][2][3][4][5][6][7][8][9]. For instance, in the last decade several polysaccharidebased products have been developed for biomedical [10], pharmaceutical [11], food packaging [12], food additive [13], environmental [14,15], sensing [16], and textile applications [17]. Among such materials, sodium alginate is one of the most promising and investigated. ...
In the present work, alginate-based mats with and without ZnO nanoparticles were prepared via electrospinning technique and subjected to a washing-crosslinking process to obtain highly stable products characterized by thin and homogeneous nanofibers with a diameter of 100 ± 30 nm. Using a commercial collagen product as control, the biological response of the prepared mats was carefully evaluated with particular attention paid to the influence of the used crosslinking agent (Ca²⁺ or Sr²⁺ or Ba²⁺ ions) and to the presence of the nanofillers. Fibroblast and keratinocyte cultures successfully proved the safety of the prepared alginate-based mats, whereas ZnO nanoparticles were found to provide strong anti-bacteriostatic and anti-bacterial properties; above all, the strontium- and barium-crosslinked samples showed performances in terms of cell adhesion and growth very similar to those of the commercial collagen membrane despite they showed a significant lower protein adsorption. Moreover, the mechanical and water-related properties of the strontium-crosslinked mats embedding ZnO nanoparticles were proven to be similar to those of human skin (i.e Young Modulus of 470 MPa and water vapour permeability of 3.8 ∙ 10⁻¹² g / m Pa s), thus proving the ability the prepared mats to be able to endure a considerable stress maintaining at the same time the fundamental ability to remove exudates. Taking into account the obtained results, the proposed alginate-based products could lead to harmless and affordable surgical patches and wound dressing membranes with a simpler and safer production procedure than the commonly employed animal collagen-derived systems.
Nowadays, consumers can estimate the condition of packaged foods only by checking the expiration date on the label. However, this approach is inefficient when it comes to assessing the actual edibility of fresh products, since the events that accelerate the onset of degradation phenomena, such as a rise in temperature, cannot be continuously assessed. In this context, the detection of a different parameter, such as low concentration of amines, can reveal the onset of degradation processes. Here, a colorimetric photonic multilayer sensor is reported for detecting low amine concentrations suitable for sealed packages. The sensor consists of alternating layers of poly(N‐vinylcarbazole) and polyacrylic acid, and its response is based on the selective interaction between the latter and amines. This interaction causes the polymer layers to swell and introduce disorder into the photon structure, resulting in fading its bright color. Since the reaction of these systems is usually reversible, manipulation or false readings are possible due to inapt sealing of the package. It is shown that the activation of carboxylic acid residues of the sensitive polymer with N‐hydroxysuccinimide produces an irreversible response to amine vapor concentrations as low as 3 parts per billion.
Distributed Bragg reflectors (DBRs) are primarily used in lasers and telecommunications. Liquid film deposition of DBRs holds great promise for expanding their utilization in environmental friendly, low‐cost, and large‐area applications. In this perspective, this work reviews the progress in solution‐based DBR research and evaluates their application in light‐emitting devices, photovoltaics and sensing. For these applications, a high refractive index contrast between the alternating layers of a DBR is important for achieving high reflectivity from only a small number of layers. While there is a plethora of solution processes that can produce low‐refractive index films, the realization of high‐refractive index films is challenging. Recent advances in materials and coating processes have addressed this challenge and novel solution‐based DBRs showed remarkable performance which is on par with traditional physical/chemical vapor phase deposition. This work examines what inhibits solution‐based DBRs, despite the great progress, to reach the stage of commercial application. In addition, this work found that DBR research is substantially extended beyond photonics, thus by summarizing materials and processes in a single table it aims to provide the necessary information to researchers with diverse backgrounds. This perspective discusses recent trends and points out the challenges in solution‐based distributed Bragg reflectors manufactured for light‐emitting, photovoltaic, and sensing applications.
Alginate is a naturally occurring polysaccharide commonly derived from brown algae cell walls which possesses unique features that make it extremely promising for several biomedical and pharmaceutical purposes. Alginate biomaterials are indeed nowadays gaining increasing interest in drug delivery and tissue engineering applications owing to their intrinsic biocompatibility, non‐toxicity, versatility, low cost, and ease of functionalization. Specifically, alginate‐based nanostructures show enhanced capabilities with respect to alginate bulk materials in the targeted delivery of drugs and chemotherapies, as well as in helping tissue reparation and regeneration. Hence, it is not surprising that the number of scientific reports related to this topic have rapidly grown in the last decade. With these premises, the present review aims to provide a comprehensive state‐of‐the‐art of the most recent advances in the preparation of alginate‐based nanoparticles and electrospun nanofibers for drug delivery, cancer therapy, and tissue engineering purposes. After a short introduction concerning the general properties and uses of alginate and the concept of nanotechnology, the recent literature is then critically presented to highlight the main advantages of alginate‐based nanostructures. Finally, the current limitations and the future perspectives and objectives are discussed in detail. Alginate nanomaterials hold great promises in the biomedical and pharmaceutical industry owing to their biocompatibility, versatility, easy fabrication, and “smart” properties. Among others, in recent years alginate nanoparticles and alginate electrospun nanofibers have gained an increasing interest in drug delivery, cancer therapy, and tissue engineering.
The present review discusses the use of cyclodextrins and their derivatives to prepare electrospun nanofibers with specific features. Cyclodextrins, owing to their unique capability to form inclusion complexes with hydrophobic and volatile molecules, can indeed facilitate the encapsulation of bioactive compounds in electrospun nanofibers allowing fast-dissolving products for food, biomedical, and pharmaceutical purposes, filtering materials for wastewater and air purification, as well as a variety of other technological applications. Additionally, cyclodextrins can improve the processability of naturally occurring biopolymers helping the fabrication of “green” materials with a strong industrial relevance. Hence, this review provides a comprehensive state-of-the-art of different cyclodextrins-based nanofibers including those made of pure cyclodextrins, of polycyclodextrins, and those made of natural biopolymer functionalized with cyclodextrins. To this end, the advantages and disadvantages of such approaches and their possible applications are investigated along with the current limitations in the exploitation of electrospinning at the industrial level.
