Ahmed A. Nada

Impregnation of silver nanoparticles into polysaccharide substrates and their properties.

A method to impregnate silver nanoparticles (AgNPs) into different polysaccharides substrates (cellulose powder (CP), microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC) and chitosan (Chit)) by using glucose as reducing agent, is presented. X-ray diffraction analyses of polysaccharides coated with AgNPs showed the formation of silver particle sizes in the range of 3.7-5.6 nm and have almost spherical shape. The entire prepared composite shows antimicrobial effect. The antibacterial activity of polysaccharides loaded with silver nanoparticles was evaluated against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. The results suggest excellent antibacterial activity.

Natural Polymers: Polysaccharides and Their Derivatives for Biomedical Applications

Abstract Several polymers of both natural and synthetic origin have been used for a variety of biomedical applications including pharmaceutical preparations, drug targeting, imaging, drug delivery, prosthetics, and tissue engineering scaffolds. Due to their reproducible characteristics in terms of their molecular weight, degradation and mechanical properties, synthetic polymers are attractive for a variety of the aforementioned applications. However, synthetic polymers from the biological standpoint, synthetic polymers often lack much-desired bioactivity and biocompatibility, which may translate into adverse side effects. Natural polymers on the other hand are abundant and resemble the components present in biological extracellular matrices. Thus, natural polymers are readily accepted by the body and possess high bioactivity and biocompatibility. Natural polymers can be divided into three major classes according to their chemical structure: (i) polysaccharides, (ii) proteins, and (iii) polyesters. This chapter presents an overview of the polysaccharide-based biomaterials, their structure property, and applications in the area of drug delivery and tissue engineering. Particular emphasis is given to polysaccharides such as (i) hyaluronic acid (HA), (ii) chondroitin sulfate, (iii) chitin and chitosan, (iv) alginates, and (v) cellulose. These polymers and their popular derivatives are also discussed in the context of their chemical and biological properties. Polysaccharides in their native form may not be able to provide all the desired properties for a particular biomedical application. Thus, the chapter also focuses on the polysaccharide derivatives and their blend with other polymers for a variety of biomedical applications.

Encapsulation of Nicotinamide into Cellulose Based Electrospun Fibers.

Systematic application of topical drugs has been widely prescribed as an effective treatment for skin disorders. However, the widespread use of such topical drugs is also associated with emergence of resistant strains of microorganisms resulting in patients resist for one or more antibiotics. Nicotinamide, a water-soluble amide of nicotinic acid and a common topical drug, is approved as anti-acne drug with anti-inflammatory potentials. Encapsulation of nicotinamide into electropun water-soluble matrix that chemically crosslinked is the approach to control its release. In this research, biocompatible nano-fibrous mat was developed with hydroxyethyl cellulose (HEC) blended with poly(vinyl alcohol) (PVA) by electro-spinning technique. The concentration of HEC (5%) with PVA (10%) was optimized, blended in different ratios (20–50% HEC concentration) and electro-spun to get smooth nano-fibers. Nicotinamide was successfully encapsulated in the electro-spun fibers. Nicotinamide release was controlled via chemical cross-linking of the produced mat. Selected parameters of spinning solutions (viscosity and conductivity) and process parameters (applied voltage and needle-to-collector distance) were studied. The microstructure, morphology of blended HEC/PVA, nicotinamide -loaded nano-fiber, cross-linked HEC/PVA nano-fibrous scaffolds were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR). SEM images showed that the mean diameters of blend nano-fibers were ranged from 80 to 60 nm. The release profile of the nicotinamide was demonstrated. Release profile of the uncrosslinked and crosslinked mats were demonstred. Immortalized human skin fibroblasts cells were used to examine the biocompatibility of the produced HEC/PVA/ nicotinamide electrospun mats.

Chitosan Liposomal microspheres for Ricinoleic acid Encapsulation

Ricinoleic acid (RA) is a C18 fatty acid (FA) with a double bond at the C 9 position and a hydroxyl group at the C(12) position (cis-12-hydroxyoctadeca-9-enoic acid). Recently, RA has been reported as a pro/anti-inflammatory and analgesic agent for topical applications to be considered as an alternative to irritant substances that relive pain. However, RA when it is exposed to air, it reacts with the oxygen and decomposes into short-chain aldehydes and ketones. Moreover, pathologically, small amount of anaesthetic agent acts on peripheral nerves, producing reversible block in transmission of peripheral nerves impulses. However, larger amounts effect potentially in the central nervous system and may cause cardiac arrest. Accordingly, extended release formulations for local anaesthetic agent such as encapsulation, are highly demanded if the drug will be used for long period. In this work, ricinoleic acid, extracted and characterized, was encapsulated into a new matrix made of phospholipid liposomes and chitosan to protect and control RA release. RA release was controlled by crosslinking the matrices using glutaraldehyde. Spectral and morphology analysis are used to characterize the produced microshpers. The cytotoxicity test is considered to examine the final product biocompatibility. The encapsulation efficiency was investigated by UV- Visible spectroscopy.

Liposomal Microencapsulation of Rodent-repelling Agents onto Jute Burlaps: Assessment of Cytotoxicity and Rat Behavioral Test -

Article history: Received on: 21/04/2016 Revised on: 10/06/2016 Accepted on: 30/06/2016 Available online: 30/08/2016 In Egypt, the world’s biggest wheat importer, about 7 to 10 percent of stored grains are damaged because of poor conditions of storage. Rodent invasion is considered as one of the main reasons that caused wheat grain damage. With respect of food safety, this work aims to treat the grain burlaps (containers) to rodent repellent. The rodent repellent agents was extracted from natural local resources. For the rodent repellent effectiveness, wheat burlaps are treated with rodent repelling agents using eco-friendly components. There are prepared using camphor oil, mint oil, and capsaicinoids (extracted from hot red pepper) as local resources to develop low cost and high-performance final product. The plan of work relies on two main axes; first, the experimental part in which burlap was treated for rodent repellent; second, testing and characterizing the treated samples for cytotoxicity and animal behavior test. The treatment was taking place by conventional pad-dry-cure technique.

Eco-friendly gelatin-based electrospun fibers to control the release of chloramphenicol

Chloramphenicol, antibiotic drug is widely used in the developing countries, may cause bone marrow suppression during its topical treatment and affecting red blood cells. Because the accumulation of high dose of chloramphenicol is necessary for this side effect, controlling its release rate is a possible approach to reduce the risk of its topical application. In the present work, chloramphenicol was encapsulated into gelatin electrospun fibers that cross-linked with non-toxic crosslinker. β-cyclodextrin, cyclic oligosaccharides of 7 membered-sugar ring, was selectively oxidized to cleave the carboncarbon bond in positions C-2 and C-3 of the glucose units to yield two aldehyde groups and end up with poly aldehyde β- cyclodextrin (PA-β-CD). Matrix was designed to control chloramphenicol release rate from nontoxic and biodegradable electrospun mat for topical applications. Bead-free electrospun fibers were produced at the concentration of 24 % w/v gelatin solution at 15 kV with gap distance of 17 cm with a flow rate of 2 ml/hr. Electrospun fibers were produced in the nanoscale (450-150 nm). 6 % of chloramphenicol was chosen to carry out the cross-linked matrices by using PA-β-CD. The encapsulation efficacy was investigated by UV-isible spectroscopy and the antimicrobial activities were demonstrated against Staphylococcus aureus (gram positive) and Pseudomonas aeruginosa (gram negative bacteria) and Candida albicans. The results showed that the samples have a strong inhibitory activity against all pathogenic microorganisms used.

Ricinoleic Acid Encapsulation into Ethyl Cellulose Electrospun Fibers

ABSTRACT Ricinoleic acid (RA), non-irritant, shows a pro- or anti-inflammatory action following its topical application. However, RA goes rancid when it is exposed to oxygen. Encapsulation of RA into ethyl cellulose (EC) electrospun fibers is the approach. RA was extracted from castor oil and characterized. Electrospinning parameters of EC, dissolved in 2:3 dimethylformamide:acetone, were optimized to obtain bead-free fibers. A 1–8 µm EC fibers were obtained at 20 kV, 0.5 mL/h feeding rate, and 20 cm air gap. RA at different concentrations was encapsulated into EC fibers. Release profile was reported and encapsulation was demonstrated via morphological analysis.

Pyrazole-based compounds in chitosan liposomal emulsion for antimicrobial cotton fabrics

The chemistry of pyrazoles has gained increasing attention due to its diverse pharmacological properties such as antiviral, antagonist, antimicrobial, anticancer, anti-inflammatory, analgesic, anti-prostate cancer, herbicidal, acaricidal and insecticidal activities. 1-Phenyl pyrazole-3, 5-diamine, 4-[2-(4-methylphenyl) diazenyl] and 1H- pyrazole-3 (1), 5-diamine, 4-[2-(4-methylphenyl) diazenyl] (2) were synthesized, characterized and encapsulated into liposomal chitosan emulsions for textile finishing. The chemical modifications of cotton fabrics were demonstrated by infrared analysis. Retention of the fabric mechanical properties was investigated by reporting the tensile strength values. Synthesized pyrazole-based compounds were screened for cytotoxicity against skin fibroblast cell line and showed very limited toxicity for both compounds. Antimicrobial potentials of the treated cotton fabrics were tested against bacterial strains E. coli ATCC 8379 and Staphylococcus aureus ATCC 25923.

Controlled Release of Drugs from Cellulosic Wound Bandage Using Silica Microsphere as Drug Encapsulator Module

Article history: Received on: 04/10/2015 Revised on: 18/10/2015 Accepted on: 09/11/2015 Available online: 27/12/2015 Controlled-drug-releasing materials show promising applications in medicinal bandages. In addition, one could incorporate drugs to make such bandages more versatile. During this context, silica microparticles were synthesized, during presence of different drugs namely sodium diclofenac, linoleic acid and recienoleic acid. The morphological characterization shows formation of monodispersed, silica microparticles. FT-IR spectroscopy provided the interaction of the drug molecule at its hydroxide (OH) site with oxygen ions on the silica surface. UV–vis spectroscopy showed persistence of the different drugs signature, especially its R group, confirming its antimicrobial activity even after conjugation. Using zone-of-inhibition studies, the antimicrobial studies were done on two microorganisms, namely, Staphylococcus aureus and Escherichia coli. However, the encapsulator module showed controlled release of all drugs for the duration of 48 h. This work demonstrated an effective protocol to prepare antimicrobial patches for controlled drug delivery.

Polysaccharide-Based Polymer Gels and Their Potential Applications

Utilization of polysaccharides as precursors to develop new polymer gels has been growing recently due to their superior inherent properties such as biodegradability, chemical activity, biocompatibility, non-toxicity, abundance, and affordable price. This chapter discusses polymer gels in terms of chemical structures, modifications, the main properties of promising polysaccharide precursors, the most common crosslinkers, and methods of crosslinking either by physical or chemical methods along with mode of interactions. It also highlights the different techniques used to characterize and evaluate the performance and functional properties of the fabricated gels as well as their potential applications in different fields. Finally, recent developments and future trends are considered to cope with the growing demands for engineering novel polymer gels for further ecofriendly successful applications.