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This study investigates the dielectric properties of conductive biocomposites (CBs), which are integral to the development of advanced materials for flexible electronics and medical devices. A novel method employing Microwave Reflectometry (MR) is introduced, utilizing a miniaturized Vector Network Analyzer (m-VNA) and a dedicated sensing element (SE), to extract the dielectric properties of CBs. The method is grounded in a minimization principle, aligning the measured S 11 reflection scattering parameter with its electromagnetic (EM) simulation, facilitating a refined process for determining the dielectric properties. The experimental setup was meticulously engineered, optimized, and validated using reference dielectric samples (RDSs) with known dielectric properties. The method was then applied to three innovative CBs, resulting in an accurate extrapolation of their dielectric properties. The findings highlight the method's versatility, cost-efficiency, and applicability to ultra-thin and flexible biopolymer films, offering significant potential for advancements in flexible electronics and bio-sensing applications. [ABSTRACT FROM AUTHOR]

Periodontitis is a global, multifaceted, chronic inflammatory disease caused by bacterial microorganisms and an exaggerated host immune response that not only leads to the destruction of the periodontal apparatus but may also aggravate or promote the development of other systemic diseases. The periodontium is composed of four different tissues (alveolar bone, cementum, gingiva, and periodontal ligament) and various non-surgical and surgical therapies have been used to restore its normal function. However, due to the etiology of the disease and the heterogeneous nature of the periodontium components, complete regeneration is still a challenge. In this context, guided tissue/bone regeneration strategies in the field of tissue engineering and regenerative medicine have gained more and more interest, having as a goal the complete restoration of the periodontium and its functions. In particular, the use of electrospun nanofibrous scaffolds has emerged as an effective strategy to achieve this goal due to their ability to mimic the extracellular matrix and simultaneously exert antimicrobial, anti-inflammatory and regenerative activities. This review provides an overview of periodontal regeneration using electrospun membranes, highlighting the use of these nanofibrous scaffolds as delivery systems for bioactive molecules and drugs and their functionalization to promote periodontal regeneration. [ABSTRACT FROM AUTHOR]

Simple Summary: The enormous demand for swabs for clinical use that has characterised recent years, together with the need to develop effective, eco-friendly, and low-cost strategies for their production, has driven nanotechnological research to the development of new manufacturing processes. In this context, electrospinning represents a promising solution as it guarantees broad control in terms of fibre size and porosity and good scalability of the production process. In this study, this technique was chosen for the fabrication of biodegradable polymeric membranes to be used for the manufacture of swab tips. The electrospun mats thus obtained were characterised, and the prototype swab thus assembled was investigated in its uptake and release properties. Furthermore, the use of this prototype for the collection of bacteriological samples was preliminarily evaluated. The in vitro tests revealed a good potential, comparable to those of commercial foam swabs adopted as the reference standard and hopefully replaceable by the manufactured prototype. In recent years, the enormous demand for swabs for clinical use has promoted their relevance and, consequently, brought the environmental issues due to their single use and lack of biodegradability to the attention of the healthcare industry. Swabs consist of a stick that facilitates their easy handling and manoeuvrability even in complex districts and an absorbent tip designed to uptake and release biological samples. In this study, we focused on the fabrication of an innovative biodegradable poly(vinyl alcohol) (PVA) nanofiber swab tip using the electrospinning technique. The innovative swab tip obtained showed comparable uptake and release capacity of protein and bacterial species (Pseudomonas aeruginosa and Staphylococcus aureus) with those of the commercial foam-type swab. In this way, the obtained swab can be attractive and suitable to fit into this panorama due to its low-cost process, easy scalability, and good uptake and release capabilities. [ABSTRACT FROM AUTHOR]

The advancement achieved in Tissue Engineering is based on a careful and in-depth study of cell–tissue interactions. The choice of a specific biomaterial in Tissue Engineering is fundamental, as it represents an interface for adherent cells in the creation of a microenvironment suitable for cell growth and differentiation. The knowledge of the biochemical and biophysical properties of the extracellular matrix is a useful tool for the optimization of polymeric scaffolds. This review aims to analyse the chemical, physical, and biological parameters on which are possible to act in Tissue Engineering for the optimization of polymeric scaffolds and the most recent progress presented in this field, including the novelty in the modification of the scaffolds' bulk and surface from a chemical and physical point of view to improve cell–biomaterial interaction. Moreover, we underline how understanding the impact of scaffolds on cell fate is of paramount importance for the successful advancement of Tissue Engineering. Finally, we conclude by reporting the future perspectives in this field in continuous development. [ABSTRACT FROM AUTHOR]

The goal of regenerative medicine is to achieve tissue regeneration. In the past, commonly used techniques included autologous or allogeneic transplantation and stem cell therapy, which have limitations, such as a lack of donor sites in the case of autologous transplantation and the invasiveness of stem cell harvesting. In recent years, research has, therefore, focused on new and less invasive strategies to achieve tissue regeneration. A step forward in this direction has been made with the development of autologous platelet concentrates (APCs), which are derived from the patient's own blood. They can be classified into three generations: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factors (CGFs). These APCs have different structural characteristics, depending on the distinctive preparation method, and contain platelets, leukocytes, and multiple growth factors, including those most involved in regenerative processes. The purpose of this review is to clarify the most used techniques in the field of regenerative medicine in recent years, comparing the different types of APCs and analyzing the preparation protocols, the composition of the growth factors, the level of characterization achieved, and their clinical applications to date. [ABSTRACT FROM AUTHOR]

Biopolymer-based formulations show great promise in enhancing the effectiveness of entomopathogenic fungi as bioinsecticides. Chitosan and starch, among other biopolymers, have been utilized to improve spore delivery, persistence, and adherence to target insects. These formulations offer advantages such as target specificity, eco-friendliness, and sustainability. However, challenges related to production costs, stability, and shelf life need to be addressed. Recently, biomimetic lure and kill approaches based on biopolymers offer cost-effective solutions by leveraging natural attractants. Further research is needed to optimize these formulations and overcome challenges. Biopolymer-based formulations have the potential to revolutionize pest control practices, providing environmentally friendly and sustainable solutions for agriculture. [ABSTRACT FROM AUTHOR]

Simple Summary: The aim of this study was to identify new and innovative strategies to improve the tissue-regeneration process. Concentrated growth factor (CGF) is an autologous biomaterial rich in growth factors and multipotent stem cells. The purpose of our study was to evaluate the osteogenic differentiation of CGF primary cells in the presence of a hydroxyapatite–silicon scaffold, which represents a very interesting material in the field of bone reconstructive surgery. Our findings showed that the hydroxyapatite–silicon scaffold provided support to primary CGF cells by enhancing osteogenic differentiation. These data suggest interesting perspectives in the use of CGF together with scaffolds in the field of regenerative medicine. The application of scaffolding materials together with stem cell technologies plays a key role in tissue regeneration. Therefore, in this study, CGF (concentrated growth factor), which represents an autologous and biocompatible blood-derived product rich in growth factors and multipotent stem cells, was used together with a hydroxyapatite and silicon (HA-Si) scaffold, which represents a very interesting material in the field of bone reconstructive surgery. The aim of this work was to evaluate the potential osteogenic differentiation of CGF primary cells induced by HA-Si scaffolds. The cellular viability of CGF primary cells cultured on HA-Si scaffolds and their structural characterization were performed by MTT assay and SEM analysis, respectively. Moreover, the matrix mineralization of CGF primary cells on the HA-Si scaffold was evaluated through Alizarin red staining. The expression of osteogenic differentiation markers was investigated through mRNA quantification by real-time PCR. We found that the HA-Si scaffold was not cytotoxic for CGF primary cells, allowing their growth and proliferation. Furthermore, the HA-Si scaffold was able to induce increased levels of osteogenic markers, decreased levels of stemness markers in these cells, and the formation of a mineralized matrix. In conclusion, our results suggest that HA-Si scaffolds can be used as a biomaterial support for CGF application in the field of tissue regeneration. [ABSTRACT FROM AUTHOR]

In the present study, we have produced a sodium carboxymethylcellulose (CMC) hydrogel from a bacterial cellulose etherification reaction with chloroacetic acid in an alkaline medium. Bacterial cellulose (BC) was synthesized via economical and environmentally friendly methods using the Gluconacetobacter xylinus bacterium. After purification, freeze-drying, and milling, BC microparticles were dispersed in NaOH solution for different time periods before the etherification reaction. This has allowed the understanding of the alkalinization effect on BC modification. All synthesized CMC were soluble in water, and FTIR and XRD analyses confirmed the etherification reaction. The bath of BC in NaOH solution affects both molecular weight and degree of substitution. SEM analysis revealed the change of BC microstructure from fibrous-like to a smooth, uniform structure. The CMC-0 h allowed the production of crosslinked hydrogel after dehydrothermal treatment. Such hydrogel has been characterized rheologically and has shown a water absorption of 35 times its original weight. The optimization of the CMC produced from BC could pave the way for the production of ultrapure hydrogel to be applied in the healthcare and pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Oral drug administration provides a convenient and patient‐compliant way for drug delivery, especially for chronic diseases and prolonged pharmacological treatments. However, due to the repetitiveness of such therapeutic approach, the patients are led to neglect/forget the therapy affecting the healthcare delivery. Indeed, the non‐adherence to pharmacological prescriptions and the unknown amount of real‐time drug release result in a non‐compliant therapeutic drug level over the protracted therapies. The proposed technology will enable the monitoring of both pharmacological adherence and real‐time drug release. The approach exploits a passive intrabody communication (IBC) activation in order to enable an edible pill, realized starting from food additives and food‐grade materials, to monitor pharmacological adherence. Following activation, the signal is modulated by IBC coupling switching triggered by pill degradation in a gastrointestinal tract, resulting in a monitored drug release. The proof‐of‐concept is designed for a targeted release and monitoring of Metformin in the intestine. The system shows an in vitro limit of cumulative drug release detection of 18 µg mL−1 and a limit of real‐time drug release detection of 2 µg mL−1 min−1. This platform represents the first solution to monitor passive drug release in real‐time, from intake to complete absorption, enabling unique and long‐sought healthcare therapy and treatment opportunity. [ABSTRACT FROM AUTHOR]

Edentulism is the condition of having lost natural teeth, and has serious social, psychological, and emotional consequences. The need for implant services in edentulous patients has dramatically increased during the last decades. In this study, the effects of concentrated growth factor (CGF), an autologous blood-derived biomaterial, in improving the process of osseointegration of dental implants have been evaluated. Here, permeation of dental implants with CGF has been obtained by using a Round up device. These CGF-coated dental implants retained a complex internal structure capable of releasing growth factors (VEGF, TGF-β1, and BMP-2) and matrix metalloproteinases (MMP-2 and MMP-9) over time. The CGF-permeated implants induced the osteogenic differentiation of human bone marrow stem cells (hBMSC) as confirmed by matrix mineralization and the expression of osteogenic differentiation markers. Moreover, CGF provided dental implants with a biocompatible and biologically active surface that significantly improved adhesion of endothelial cells on CGF-coated implants compared to control implants (without CGF). Finally, data obtained from surgical interventions with CGF-permeated dental implants presented better results in terms of optimal osseointegration and reduced post-surgical complications. These data, taken together, highlight new and interesting perspectives in the use of CGF in the dental implantology field to improve osseointegration and promote the healing process. [ABSTRACT FROM AUTHOR]

Pest management is looking for green and cost-effective innovative solutions to control tiger mosquitoes and other pests. By using biomimetic principles and biocompatible/biodegradable biopolymers, it could be possible to develop a new approach based on substrates that selectively attract insects by reproducing specific natural environmental conditions and then kill them by hosting and delivering a natural biopesticide or through mechanical action (biomimetic lure and kill approach, BL&K). Such an approach can be theoretically specialized against tiger mosquitoes (BL&K-TM) by designing hydrogels to imitate the natural oviposition site's conditions to employ them inside a lure and kill ovitraps as a biomimetic oviposition substrate. In this work, the hydrogels have been prepared to prove the concept. The study compares lab/on-field oviposition between standard substrates (absorbing paper/masonite) and a physical and chemically crosslinked hydrogel composition panel. Then the best performing is characterized to evaluate a correlation between the hydrogel's properties and oviposition. Tests identify a 2-Hydroxyethylcellulose (HEC)-based physical hydrogel preparation as five times more attractive than the control in a lab oviposition assay. When employed on the field in a low-cost cardboard trap, the same substrate is seven times more capturing than a standard masonite ovitrap, with a duration four times longer. [ABSTRACT FROM AUTHOR]

Background: Pest management has been facing the spread of invasive species, insecticide resistance phenomena, and concern for the impact of chemical pesticides on human health and the environment. It has tried to deal with them by developing technically efficient and economically sustainable solutions to complement/replace/improve traditional control methods. The renewal has been mainly directed towards less toxic pesticides or enhancing the precision of their delivery to reduce the volume employed and side effects through lure-and-kill approaches based on semiochemicals attractants. However, one of the main pest management problems is that efficacy depends on the effectiveness of the attractant system, limiting its successful employment to semiochemical stimuli-responsive insects. Biomaterial-based and bioinspired/biomimetic solutions that already guide other disciplines (e.g., medical sciences) in developing precision approaches could be a helpful tool to create attractive new strategies to liberate precision pest management from the need for semiochemical stimuli, simplify their integration with bioinsecticides, and foster the use of still underemployed solutions. Approach proposed: We propose an innovative approach, called "biomimetic lure-and-kill". It exploits biomimetic principles and biocompatible/biodegradable biopolymers (e.g., natural hydrogels) to develop new substrates that selectively attract insects by reproducing specific natural environmental conditions (biomimetic lure) and kill them by hosting and delivering a natural biopesticide or through mechanical action. Biomimetic lure-and-kill-designed substrates point to provide a new attractive system to develop/improve and make more cost-competitive new and conventional devices (e.g. traps). A first example application is proposed using the tiger mosquito Aedes albopictus as a model. Conclusions: Biomaterials, particularly in the hydrogel form, can be a useful tool for developing the biomimetic lure-and-kill approach because they can satisfy multiple needs simultaneously (e.g., biomimetic lure, mechanical lethality, biocompatibility, and bioinsecticide growth). Such an approach might be cost-competitive, and with the potential for applicability to several pest species. Moreover, it is already technically feasible, since all the technologies necessary to design and configure materials with specific characteristics are already available on the market. [ABSTRACT FROM AUTHOR]

Objective: This study aims to assess the efficacy and safety of Gelesis100, a novel, nonsystemic, superabsorbent hydrogel to treat overweight or obesity.Methods: The Gelesis Loss Of Weight (GLOW) study was a 24-week, multicenter, randomized, double-blind, placebo-controlled study in patients with BMI ≥  27 and ≤ 40 kg/m2 and fasting plasma glucose ≥ 90 and ≤ 145 mg/dL. The co-primary end points were placebo-adjusted weight loss (superiority and 3% margin super-superiority) and at least 35% of patients in the Gelesis100 group achieving ≥ 5% weight loss.Results: Gelesis100 treatment caused greater weight loss over placebo (6.4% vs. 4.4%, P = 0.0007), achieving 2.1% superiority but not 3% super-superiority. Importantly, 59% of Gelesis100-treated patients achieved weight loss of ≥ 5%, and 27% achieved ≥ 10% versus 42% and 15% in the placebo group, respectively. Gelesis100-treated patients had twice the odds of achieving ≥ 5% and ≥ 10% weight loss versus placebo (adjusted OR: 2.0, P = 0.0008; OR: 2.1, P = 0.0107, respectively), with 5% responders having a mean weight loss of 10.2%. Patients with prediabetes or drug-naive type 2 diabetes had six times the odds of achieving ≥ 10% weight loss. Gelesis100 treatment had no apparent increased safety risks.Conclusions: Gelesis100 is a promising new nonsystemic therapy for overweight and obesity with a highly desirable safety and tolerability profile. [ABSTRACT FROM AUTHOR]

In this work, a time domain reflectometry (TDR)-based system for continuous and diffused monitoring of soil water content in agriculture is presented. The proposed TDR-based system employs elongate sensing elements (SEs). In practical application, each wire-like SE is buried along the cultivation row to be monitored, and through a single TDR measurement it is possible to retrieve the water content profile of the cultivation along the length of the SE. By connecting the TDR-based monitoring system to the irrigation machines, it would be possible to automatically start/stop irrigation based on the actual water requirement of the cultivations, thus favoring precision agriculture and enhancing irrigation efficiency. To demonstrate the feasibility of the proposed monitoring solution, a dedicated hardware+software platform was developed and the TDR-based system was experimented in open-field cultivations. [ABSTRACT FROM AUTHOR]

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Abstract: Herein, we propose the fabrication of a new carrier with core/shell structure—inner core of cellulose acetate (CA) coated by a micrometric layer of chitosan (CS)—fabricated through an integrated process, which combines Electro Dynamic Atomization (EDA) and layer‐by‐layer (LbL) technique. We demonstrate that CA based microspheres possess a unique capability to relevantly retain the drugs—that is, Ketoprofen Lysinate (KL)—along the gastric tract, while providing a massive release along the intestine. CS shell slightly influences the morphology and water retention under different pH conditions, improving drug encapsulation without compromising drug release kinetics. In vitro studies in simulated gastric and intestine fluids (SGF, SIF) with physiological enzymes, show a moderate release of LSK during the first 2 h (ca. 20% at pH 2), followed by a sustained release during the next 6 h (ca. 80% at pH 7). The obtained results demonstrate that CA‐based microspheres hold strong potential to be used as carriers for a delayed oral administration of anti‐inflammatory drugs. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2636–2644, 2018. [ABSTRACT FROM AUTHOR]

Abstract: Biodegradable cellulose-based hydrogels are attracting increasing interest in the academic and industrial fields thanks to their high swelling capacity and reproducibility, which allow many novel applications. These properties are enabled by amplification effect of their sensitiveness on a molecular level, translated into macroscopic effects such as a change in swelling degree. The monitoring of the hydrogel state is a crucial step for understanding the response of the hydrogel to external environment. Accordingly, the major aim of this study is to exploit ultrasound to characterize the swelling and degradation of cellulose-based hydrogel with different blend of molecular weight and degree of substitutions. The ultrasonic sensor used herein relies on the determination of a Pulse-echo time of flight. This technique provides dimensional information, thanks to its capability of monitoring the thickness of the swollen/unswollen hydrogel during sorption mechanism. Furthermore, by combining these data with a rheological characterization, the degree of crosslink and its modification during multiple swelling/deswelling cycles (due to ion strength variation) has been monitored. This technique could be an effective, alternative, fast and non-destructive method for real-time hydrogel characterization.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract: This study reports on the development of a scaffold with a gradient of bioactive solid signal embedded in the biodegradable polymer matrix by combining a sol–gel approach and freeze‐drying technology. The chemical approach based on the sol–gel transition of calcium phosphates ensures the particles dispersion into the gelatin matrix and a direct control of interaction among COOHgelatin/Ca2+ ions. Morphological analysis demonstrated that on the basis of the amount of inorganic component and by using specific process conditions, it is possible to control the spatial distribution of nanoparticles around the gelatin helix. In fact, methodology and formulations were able to discriminate between the different hydroxyapatite concentrations and their respective morphology. The good biological response represented by good cell attachment, proliferation and increased levels of alkaline phosphatase as an indicator of osteoblastic differentiation of human mesenchymal stem cells toward the osteogenic lineage, demonstrating the effect of bioactive solid signals on cellular behavior. Furthermore, the inhibition of reactive oxygen species production by composite materials predicted potential anti‐inflammatory properties of scaffolds thus confirming their biocompatibility. Indeed, these interesting biological results suggest good potential application of this scaffold as filler to repair bone defects. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2007–2019, 2018. [ABSTRACT FROM AUTHOR]

In this work, tunable nonwoven mats based on poly(3-hydroxybutyrate) (PHB) and type I collagen (Coll) were successfully produced by electrospinning. The PHB/Coll weight ratio (fixed at 100/0, 70/30, and 50/50, resp.) was found to control the morphological, thermal, mechanical, and degradation properties of the mats. Increasing collagen amounts led to larger diameters of the fibers (in the approximate range 600–900 nm), while delaying their thermal decomposition (from 245°C to 262°C). Collagen also accelerated the hydrolytic degradation of the mats upon incubation in aqueous medium at 37°C for 23 days (with final weight losses of 1%, 15%, and 23% for 100/0, 70/30, and 50/50 samples, resp.), as a result of increased mat wettability and reduced PHB crystallinity. Interestingly, 70/30 meshes were the ones displaying the lowest stiffness (~116 MPa; p<0.05 versus 100/0 and 50/50 meshes), while 50/50 samples had an elastic modulus comparable to that of 100/0 ones (~250 MPa), likely due to enhanced physical crosslinking of the collagen chains, at least at high protein amounts. All substrates were also found to allow for good viability and proliferation of murine fibroblasts, up to 6 days of culture. Collectively, the results evidenced the potential of as-spun PHB/Coll meshes for tissue engineering applications. [ABSTRACT FROM AUTHOR]

The authors have recently developed a time‐domain reflectometry (TDR)‐based leak‐localisation system which, being based on an electromagnetic technique, overcomes the well‐known downsides (sensitivity to environmental noise, to pipe material and geometry etc.) of traditional, electro‐acoustic leak‐localisation techniques. Starting from the positive results obtained so far, in this work, the authors investigate the possibility of implementing an integrated TDR/ground penetrating radar (TDR/GPR) approach. The TDR would allow the preliminary leak localisation, while the GPR technique would be used to have a countercheck for possible false positives. Also, GPR would allow to assess the quantity of the leaked water (thus scheduling a priority order for repair) and to obtain a three‐dimensional view of the subsurface soil around the pipes, so as to assess their health status. In this work, the combined TDR/GPR approach is tested on a pipe section in the presence of two leaks. In addition to this, in this study, also a different configuration of the TDR sensing element (SE) is experimented. As described in what follows, this new SE configuration is expected to expedite considerably the implementation and the use of the TDR‐based leak detection system. [ABSTRACT FROM AUTHOR]

Genipin (GN) is a natural molecule extracted from the fruit of Gardenia jasminoides Ellis according to modern microbiological processes. Genipin is considered as a favorable cross-linking agent due to its low cytotoxicity compared to widely used cross-linkers; it cross-links compounds with primary amine groups such as proteins, collagen, and chitosan. Chitosan is a biocompatible polymer that is currently studied in bone tissue engineering for its capacity to promote growth and mineral-rich matrix deposition by osteoblasts in culture. In this work, two genipin cross-linked chitosan scaffolds for bone repair and regeneration were prepared with different GN concentrations, and their chemical, physical, and biological properties were explored. Scanning electron microscopy and mechanical tests revealed that nonremarkable changes in morphology, porosity, and mechanical strength of scaffolds are induced by increasing the cross-linking degree. Also, the degradation rate was shown to decrease while increasing the cross-linking degree, with the high cross-linking density of the scaffold disabling the hydrolysis activity. Finally, basic biocompatibility was investigated in vitro, by evaluating proliferation of two human-derived cell lines, namely, the MG63 (human immortalized osteosarcoma) and the hMSCs (human mesenchymal stem cells), as suitable cell models for bone tissue engineering applications of biomaterials. [ABSTRACT FROM AUTHOR]

Due to its intrinsic biocompatibility, degradability, and antibacterial properties, chitosan is widely explored for biomedical and pharmaceutical applications, especially for the development of tissue engineering scaffolds and controlled drug delivery systems. In this work, physically crosslinked chitosan-based particles with submicrometric size were synthesized by means of a modified coacervation process, starting from aqueous solutions differing for the chitosan molecular weight and concentration. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to analyse the particle morphology and the mean diameter yielded by the different synthesis parameters. Daily DLS measurements were also performed to monitor the expected swelling of the particles in a buffer solution, up to four days of storage. The experimental findings showed that submicrometric chitosan particles, with an average diameter in the range 150–400 nm, could be successfully produced, with both chitosan molecular weight and concentration affecting the particle size. Moreover, the smallest particles, among those synthesized, were found to be stable in water solutions up to three days. This seems to suggest the potential of the investigated particles for short-term biomedical applications, e.g., controlled drug delivery over time windows ranging from hours to days. [ABSTRACT FROM PUBLISHER]

Bioactive food-preserving materials are based on the use of a natural antimicrobial compound loaded in a carrier material, which is able to trigger its release when requested and to modulate the rate of release, thus using either toxic or inhibitory properties against pathogens or bacteria due to food decomposition. In this study, the Schiff base formation for chitosan functionalization was achieved by the reaction of chitosan with cinnamaldehyde at different concentrations. Cinnamaldehyde is an aromatic α,β-unsaturated aldehyde, and the major component in essential oils from some cinnamon species. It has been shown to exert antimicrobial action against a large number of microorganisms including bacteria, yeasts, and mould. The formation of the Schiff base is reversible under suitable conditions, and this might allow the release of the active cinnamaldehyde from chitosan, used as the carrier. The reaction kinetics was investigated by means of rheological measurements, while infrared spectroscopy was used to assess the efficacy of the functionalization. The addition of nanometric graphene stacks to the cinnamaldehyde-functionalized chitosan films was evaluated with the aim to increase the mechanical properties of the film. Finally, the films were tested for antifungal properties with bread slices against a selected mould line. [ABSTRACT FROM AUTHOR]

The Mark-Houwink-Sakurada (MHS) equation allows for estimation of rheological properties, if the molecular weight is known along with good understanding of the polymer conformation. The intrinsic viscosity of a polymer solution is related to the polymer molecular weight according to the MHS equation, where the value of the constants is related to the specific solvent and its concentration. However, MHS constants do not account for other characteristics of the polymeric solutions, i.e., Deacetilation Degree (DD) when the solute is chitosan. In this paper, the degradation of chitosan in different acidic environments by thermal treatment is addressed. In particular, two different solutions are investigated (used as solvent acetic or hydrochloric acid) with different concentrations used for the preparation of chitosan solutions. The samples were treated at different temperatures (4, 30, and 80 °C) and time points (3, 6 and 24 h). Rheological, Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analyses (TGA) were performed in order to assess the degradation rate of the polymer backbones. Measured values of molecular weight have been integrated in the simulation of the batch degradation of chitosan solutions for evaluating MHS coefficients to be compared with their corresponding experimental values. Evaluating the relationship between the different parameters used in the preparation of chitosan solutions (e.g., temperature, time, acid type and concentration), and their contribution to the degradation of chitosan backbone, it is important to have a mathematical frame that could account for phenomena involved in polymer degradation that go beyond the solvent-solute combination. Therefore, the goal of the present work is to propose an integration of MHS coefficients for chitosan solutions that contemplate a deacetylation degree for chitosan systems or a more general substitution degree for polymers in which viscosity depends not only on molecular weight and solvent combinations. [ABSTRACT FROM AUTHOR]

Physical foaming combined with microwave-induced curing was used in this study to develop an innovative device for bone tissue regeneration. In the first step of the process, a stable physical foaming was induced using a surfactant (i.e. pluronic) as blowing agent of a homogeneous blend of Sodium salt of carboxymethylcellulose (CMCNa) and polyethylene glycol diacrylate (PEGDA700) solution. In the second step, the porous structure of the scaffold was chemically stabilized by radical polymerization induced by a homogeneous rapid heating of the sample in a microwave reactor. In this step 2,2-Azobis[2-(2-imidazolin-2 yl)propane]Dihydrochloride was used as thermoinitiator (TI). CMCNa and PEGDA were mixed with different blends to correlate the properties of final product with the composition. The chemical properties of each sample were evaluated by spectroscopy analysis ATR-IR (before and after curing) in order to maximize reaction yield, and optimize kinetic parameters (i.e. time curing, microwave power). The stability of the materials was evaluated in vitro by degradation test in Phosphate Buffered Saline. Biological analyses were performed to evaluate the effect of scaffold materials on cellular behavior in terms of proliferation and early osteogenic differentiation of human Mesenchymal Stem Cells. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 726-733, 2016. [ABSTRACT FROM AUTHOR]

In this study, free-standing expanded graphite chitosan (EG-chitosan) nanocomposite films have been prepared using a novel green and simple preparation method, starting from a commercial expandable graphite (GIC). The in situ exfoliation of GIC by a solvent-free sonication method was monitored as a function of the process parameters using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV-visible transmittance (UV-VIS) analyses. The optimal process parameters were selected in order to obtain an efficient dispersion of EG in chitosan solutions. The effective EG amount after the in situ exfoliation was also determined by thermogravimetric analyses. [ABSTRACT FROM AUTHOR]

ABSTRACT The main aim of this work is the synthesis and characterization of cross-linked chitosan systems. Chitosan hydrogels can be prepared by physical or chemical cross-linking of polymer chains. Chemical cross-linking, leading to the creation of hydrogel networks possessing improved mechanical properties and chemical stability, can be achieved using either synthetic agents or natural-based agents. In this work, the cross-linker Genipin, a naturally derived compound, was selected because of the lower acute toxicity compared to many other commonly used synthetic cross-linking reagents. In particular, the chemical stabilization of chitosan through genipin cross-linking molecules was performed and characterized by calorimetric analyses (differential scanning calorimetry), swelling measurements in different pHs, and ionic strength. The reaction kinetics was carried out by means of rheological measurements, and both the activation energy ( Ea) and the reaction order ( m) were calculated. The hydrogel analyses were carried out at different concentrations of genipin (GN1 and GN2). The results were used to evaluate the possibility to use the chemical cross-linked chitosan-genipin hydrogel for biomedical applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42256. [ABSTRACT FROM AUTHOR]

In this work, an innovative cellulose-based superabsorbent polymer (SAP) was experimentally assessed as an environmentally friendly alternative to acrylate-based SAPs, for the optimization of water consumption in agriculture. The cellulose-based SAP was synthesized and tested for its swelling capability in different aqueous media. The effectiveness of the SAP in agricultural applications was then evaluated by analyzing its performance after several absorption/desorption cycles, over a period of approximately 80 days, upon addition to different types of soil, i.e., white and red soil, for the cultivation of two varieties of plants typical of the Mediterranean area (tomatoes and chicory). The results confirmed that SAP-amended soil can store a considerable amount of water and can release it gradually to the plant roots when needed. The adoption of the proposed SAP in cultivations could thus represent a promising solution for the rationalization of water resources, especially in desert areas. [ABSTRACT FROM AUTHOR]