Hybrid Nanostructures Containing Sulfadiazine Modified Chitosan as Antimicrobial Drug Carriers

Electrospinning of chitosan-based nanofibers: from design to prospective applications

Chitosan is a biopolymer originating from renewable resources, with great properties which make it an attractive candidate for plenty of applications of contemporary interest. By manufacturing chitosan into nanofibers using the electrospinning method, its potential is amplified due to the enhancement of the active surface and the low preparation cost. Many attempts were made with the aim of preparing chitosan-based nanofibers with controlled morphology targeting their use for tissue engineering, wound healing, food packaging, drug delivery, air and water purification filters. This was a challenging task, which resulted in a high amount of data, sometimes with apparent contradictory results. In this light, the goal of the paper is to present the main routes reported in the literature for chitosan electrospinning, stressing the advantages and disadvantages of each of them. Special emphasis is placed on the influence of various electrospinning parameters on the morphological characteristics of the fibers and their suitability for distinct applications.

Vegetable Additives in Food Packaging Polymeric Materials

Plants are the most abundant bioresources, providing valuable materials that can be used as additives in polymeric materials, such as lignocellulosic fibers, nano-cellulose, or lignin, as well as plant extracts containing bioactive phenolic and flavonoid compounds used in the healthcare, pharmaceutical, cosmetic, and nutraceutical industries. The incorporation of additives into polymeric materials improves their properties to make them suitable for multiple applications. Efforts are made to incorporate into the raw polymers various natural biobased and biodegradable additives with a low environmental fingerprint, such as by-products, biomass, plant extracts, etc. In this review we will illustrate in the first part recent examples of lignocellulosic materials, lignin, and nano-cellulose as reinforcements or fillers in various polymer matrices and in the second part various applications of plant extracts as active ingredients in food packaging materials based on polysaccharide matrices (chitosan/starch/alginate).

Preparation of Coaxial Polylactic Acid-Propyl Gallate Electrospun Fibers and the Effect of Their Coating on Salmon Slices during Chilled Storage

Pseudomonas fluorescens bacteria can grow well in cold-storage conditions and cause food spoilage. Quorum sensing (QS) is a biological pathway existing in a large number of microorganisms, through which bacteria regulate several of their physiological activities. A number of substances have been identified as quorum sensing inhibitors (QSIs); they can interfere with the QS system and control bacterial spoilage characteristics and production of virulence factors. In our previous study, propyl gallate at sub-minimum inhibitory concentration levels showed a potent anti-QS activity. Thus, in this study, coaxial polylactic acid-propyl gallate electrospun fibers were fabricated and their physicochemical properties were characterized. Salmon slices were coated with these electrospun fibers and the effect of this coating on the salmon slices during chilled storage was evaluated. The results showed that the electrospun fibers had a small diameter and smooth surface with no beads or other defects. The thermal stability, tensile strength, and other properties of the fibers were suitable for refrigerated storage conditions. Without inhibiting the bacterial growth in the salmon slices, the QSI-containing electrospun fibers exerted a significant inhibitory effect on the production of total volatile base nitrogen and trimethylamine. Furthermore, the deterioration of muscle tissue in the salmon slices was significantly delayed during cold storage. Quantitative analysis indicated that the electrospun fibers had a significant inhibitory effect on the bacterial spoilage ability. The results suggested that the electrospun fibers loaded with QSIs might be an effective strategy to control food spoilage and enhance the quality of aquatic food products.

Polymeric Nanocomposites and Nanocoatings for Food Packaging: A Review

Special properties of the polymeric nanomaterials (nanoscale size, large surface area to mass ratio and high reactivity individualize them in food packaging materials. They can be processed in precisely engineered materials with multifunctional and bioactive activity. This review offers a general view on polymeric nanocomposites and nanocoatings including classification, preparation methods, properties and short methodology of characterization, applications, selected types of them used in food packaging field and their antimicrobial, antioxidant, biological, biocatalyst and so forth, functions.

Single-stage electrospun innovative combination of polyurethane and neem oil: Synthesis, characterization and appraisal of blood compatibility

Wound healing is a complex process and it requires proper scaffolding for regeneration. An ideal scaffold should provide optimal environmental conditions in order to assist cellular attachment, proliferation and differentiation. In this work, a new composite based on polyurethane and neem oil was fabricated using one-step electrospinning technique. Fabricated composite patch along with the pristine polyurethane was characterized through scanning electron microscopy, Fourier transform and infrared spectroscopy, thermogravimetric analysis, contact angle measurement and atomic force microscopy. Moreover, the blood compatibility was evaluated using activated partial thromboplastin time, partial thromboplastin time and haemolysis assay. Scanning electron microscopy studies of composites revealed the existence of fibres with a smaller diameter (635  ± 105 nm) compared to the pristine polyurethane (969 ± 217 nm). Fourier transform and infrared analysis revealed the formation of hydrogen bond and peak shifting characteristics confirming the interaction of the neem oil with the polyurethane. Contact angle analysis showed the decrease in contact angle indicating the hydrophilic nature of the fabricated patch compared to pristine polyurethane. Thermal gravimetric analysis depicted the better thermal stability of the novel composite patch due to the existence of neem oil in the pristine polyurethane. The presence of neem oil in polyurethane matrix also resulted in an increase in the surface roughness as observed in the AFM analysis. The novel composite patch showed an ability to reduce the thrombogenicity and promoting the anticoagulant nature signified by blood compatibility assays like activated partial thromboplastin time and partial thromboplastin time. Finally, the haemolytic percentage of the fabricated composite (1%) was found to be reduced compared to control (2.733%) indicating better blood compatibility and safety with the red blood cells. Following the results, the fabricated patches offered enhanced physicochemical and blood compatible nature making it as a promising candidate for wound healing application.

Electrospun Blank Nanocoating for Improved Sustained Release Profiles from Medicated Gliadin Nanofibers

Nanomaterials providing sustained release profiles are highly desired for efficacious drug delivery. Advanced nanotechnologies are useful tools for creating elaborate nanostructure-based nanomaterials to achieve the designed functional performances. In this research, a modified coaxial electrospinning was explored to fabricate a novel core-sheath nanostructure (nanofibers F2), in which a sheath drug-free gliadin layer was successfully coated on the core ketoprofen (KET)-gliadin nanocomposite. A monolithic nanocomposite (nanofibers F1) that was generated through traditional blending electrospinning of core fluid was utilized as a control. Scanning electron microscopy demonstrated that both nanofibers F1 and F2 were linear. Transmission electron microscopy verified that nanofibers F2 featured a clear core-sheath nanostructure with a thin sheath layer about 25 nm, whereas their cores and nanofibers F1 were homogeneous KET-gliadin nanocomposites. X-ray diffraction patterns verified that, as a result of fine compatibility, KET was dispersed in gliadin in an amorphous state. In vitro dissolution tests demonstrated that the thin blank nanocoating in nanofibers F2 significantly modified drug release kinetics from a traditional exponential equation of nanofibers F1 to a zero-order controlled release model, linearly freeing 95.7 ± 4.7% of the loaded cargoes over a time period of 16 h.

Alginate modified with maleimide-terminated PEG as drug carriers with enhanced mucoadhesion

The goal of this study was to generate a new mucoadhesive carbohydrate-based delivery system composed of alginate (Alg) backbone covalently attached to polyethylene glycol (PEG) modified with a unique functional end-group (maleimide). The immobilization of PEG-maleimide chains significantly improved the mucoadhesion properties attributed to thioether bonds creation via Michael-type addition and hydrogen bonding with the mucus glycoproteins. Mucoadhesion studies using tensile and rotating cylinder assays revealed a 3.6-fold enhanced detachment force and a 2.8-fold enhanced retention time compared to the unmodified polymer, respectively. Additional indirect studies confirmed the presence of polymer-mucus glycoproteins interactions. Drug release experiments were used to evaluate the release profiles from Alg-PEG-maleimide tablets in comparison to Alg and Alg-SH tablets. Viability studies of normal human dermal fibroblasts cells depicted the non-toxic nature of Alg-PEG-maleimide. Overall, our studies disclose that PEG-maleimide substitutions on other biocompatible polymers can lead to the development of useful biomaterials for diverse biomedical applications.

Release of Doxorubicin by a Folate-Grafted, Chitosan-Coated Magnetic Nanoparticle

In clinical tumor therapy, chemotherapeutic routes have caused severe side effects; current delivery methods are unsatisfactory. Successful design of a remotely folate (FA)-grafted chitosan (CS)-coated magnetic nanoparticle (MNP) with low toxicity, has been achieved. A chemotherapeutic drug such as doxorubicin (DOX), is loaded in the MNP-based matrix (FA-grafted CS-DOX-_TPP-MNP), which is coated by an activated target tumor molecule of FA-grafted CS biopolymer with the inclusion of tripolyphosphate (TPP) as a linker. The resultant nano-complexes exhibited random aggregates (~240 nm) and zeta potential (−24.9 mV). In vivo experiments using athymic BALB/c nude mice with human glioblastoma U87 cells in a subcutaneous tumor model revealed that magnetic guidance of FA-grafted CS-DOX-_TPP-MNP, injected via the tail vein, significantly decreased tumor growth. This manuscript demonstrates the feasibility of magnetizing control of FA-grafted CS-DOX-_TPP-MNP to enhance the localization of drug release.