Polycaprolactone-polymethyl methacrylate electrospun blends for biomedical applications

Electrospinning is one of most versatile process to fabricate porous scaffolds in biomedical field. Synthetic polymers such as polycaprolactone (PCL) and polymethyl methacrylate (PMMA) provide excellent properties for biomedical applications due to their biocompatibility and tunable mechanical properties. PCL-PMMA electrospun blends combine compressive/tensile properties of individual polymers as well as biocompatibility/biodegradability. Together with porosity of scaffold, drug/nutrient supply is required in tissue regeneration and healing. High pressure CO₂ has been investigated to plasticize many biopolymers and impregnate drugs in scaffolds. This study explores several compositions of PCL-PMMA electrospun scaffolds for morphological and mechanical properties. These scaffolds are impregnated with hydrophilic (Rhodamine B) and hydrophobic (Fluorescein) dyes using high pressure CO₂ and air plasma treatment. Furthermore, release profiles of dyes have been studied from thin films and porous scaffolds to understand several controlling factors for controlled release applications. Results show dye-polymer interactions, CO₂ impregnation and stress relaxation of electrospun fibers are key factors in release profile from electrospun fibers. This study is a step forward in developing PCL-PMMA based electrospun scaffolds for drug delivery and tissue engineering.     

Mexican Oregano (Lippia graveolens Kunth) as Source of Bioactive Compounds: A Review

Lippia graveolens is a traditional crop and a rich source of bioactive compounds with various properties (e.g., antioxidant, anti-inflammatory, antifungal, UV defense, anti-glycemic, and cytotoxicity) that is primarily cultivated for essential oil recovery. The isolated bioactive compounds could be useful as additives in the functional food, nutraceuticals, cosmetics, and pharmaceutical industries. Carvacrol, thymol, β-caryophyllene, and p-cymene are terpene compounds contained in oregano essential oil (OEO); flavonoids such as quercetin O-hexoside, pinocembrin, and galangin are flavonoids found in oregano extracts. Furthermore, thermoresistant compounds that remain in the plant matrix following a thermal process can be priced in terms of the circular economy. By using better and more selective extraction conditions, the bioactive compounds present in Mexican oregano can be studied as potential inhibitors of COVID-19. Also, research on extraction technologies should continue to ensure a higher quality of bioactive compounds while preventing an undesired chemical shift (e.g., hydrolysis). The oregano fractions can be used in the food, health, and agricultural industries.     

A review on electrospun nanofibers for multiple biomedical applications

Electrospinning is a well-known technique since 1544 to fabricate nanofibers using different materials like polymers, metals oxides, proteins, and many more. In recent years, electrospinning has become the most popular technique for manufacturing nanofibers due to its ease of use and economic viability. Nanofibers have remarkable properties like high surface-to-volume ratio, variable pore size distribution (10–100 nm), high porosity, low density, and are suitable for surface functionalization. Therefore, electrospun nanofibers have been utilized for numerous applications in the pharmaceutical and biomedical field like tissue engineering, scaffolds, grafts, drug delivery, and so on. In this review article, we will be focusing on the versatility, current scenario, and future endeavors of electrospun nanofibers for various biomedical applications. This review discusses the properties of nanofibers, the background of the electrospinning technique, and its emergence in chronological order. It also covers the various types of electrospinning methods and their mechanism, further elaborating the factors affecting the properties of nanofibers, and applications in tissue engineering, drug delivery, nanofibers as biosensor, skin cancer treatment, and magnetic nanofibers.     

Biological amphiphiles (microbial biosurfactants)

Low- and high-molecular-weight biosurfactants are of great interest because of their physicochemical and biological properties, which can be exploited in oil, food, cosmetic and pharmaceutical industries. As for the general types of microbial amphiphiles, the data accumulated over recent years are adding new interesting molecular structures to well-known compounds. Using new strains and cultivation conditions, positive results were found in basic studies of lowering the surface tension of water (72 mN/m→27 mN/m, cmc: 150 mg/l; rhamnose lipids from Pseudomonas aeruginosa), of size determinations of micelles and vesicles (iturin A, a lipopeptide from Bacillus subtilis), of emulsifying properties, biological activities, as well as of application tests in soil remediation.     

Monitoring the effects of component structure and source on formulation stability and adjuvant activity of oil-in-water emulsions

Oil-in-water emulsions have shown promise as safe and effective adjuvant formulations for vaccines. In particular, formulations consisting of metabolizable oils such as shark-derived squalene and detergents such as egg phosphatidylcholine have been used to produce stable vaccine emulsion formulations. However, there is an emphasis in pharmaceutical regulatory bodies on using synthetic or plant-derived components from sustainable sources instead of animal-derived components. This study compares the physicochemical properties and biological efficacy of emulsions consisting of oil and detergent components from animal, plant, and synthetic sources. In particular, effects of component structure and source on emulsion stability and biological activity are examined. It is shown that oil-in-water emulsions using animal-derived components can be substituted with synthetic or plant-derived materials while still exhibiting satisfactory physicochemical and biological properties.     

Exploration of an arabinogalactan isolated from Odina wodier Roxb.: Physicochemical,compositional characterisations and functional attributes

Exudate gum polysaccharides have a diverse range of functionalities in food, cosmetics, textiles, biomedical, pharmaceutical and other industries for centuries. The potentiality of gum odina as tablet binder, coacervates (chitosan‐gum odina complex) for colon‐targeted drug delivery system and also as prebiotic with immunomodulating properties was reported earlier. Since no detail study of the physicochemical, functional properties of the gum has been reported, the present investigation deals with physicochemical, compositional and functional characterisations of purified gum odina (PGO) for adopting in food and pharmaceutical industry. PGO, an arabinogalactan, was obtained by ethanol precipitation from exudates (gum odina) of tropical deciduous plant Odina wodier Roxb. Colour profiling of PGO including L* (87.74 ± 0.42), a* (1.73 ± 0.65) and b* (7.79 ± 0.58) was determined. Physicochemical parameters revealed good flow ability and compressibility desired for an excipient. Concentration‐dependent surface tension was measured by du Noüy ring method. Rheological study showed pseudoplastic behaviour of PGO dispersion. Sugar analysis by gas liquid chromatography indicated presence of arabinogalactan in PGO. Size exclusion chromatography of PGO revealed two high‐molecular‐weight components PGO‐I (95%, Arabinose:Galactose :: 1:1.6) and PGO‐II (5%, Arabinose:Galactose :: 1:4). Further characterisations of PGO by means of CHNS, FTIR, differential scanning calorimetry, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy and energy‐dispersive X‐ray diffraction, conductivity, pH, zeta potential analysis and antioxidant activity indicated typical polysaccharide characteristics. Collectively, this work established the fundamental properties of PGO and the results presented here will facilitate the applications of PGO as sustainable food additive, pharmaceutical excipient for commercial adoption.     

Novel approaches for biotechnological production and application of L-arabinose

Abstract

L-arabinose is found in biopolymers such as hemicellulose, pectin, arabinogalactan-protein complexes, and polysaccharides of exudate plant gums. Recent studies have revealed many possible applications of L-arabinose in the fields of pharmaceutical, food and chemical industries. Novel approaches to obtain L-arabinose are focused on the utilization of lignocellulosic by-products, purified polysaccharides, and residual hydrolysates containing a mixture of sugars. L-arabinose can be released from lignocellulosic biomasses by acid-catalysed or enzymatic hydrolysis. L-arabinose-enriched solutions can be obtained from residual hydrolysates by yeast-mediated biopurification. The most promising, novel processes to obtain L-arabinose have combined the advantages of different methods but technological barriers still exist impeding the industrial implementation.     

Biomedical applications of electrospun polycaprolactone fiber mats

Polycaprolactone (PCL) is a biodegradable polyester emerging into biomedical applications because of its biodegradability, biocompatibility, chemical stability, thermal stability and good mechanical properties. Electrospinning is a versatile method using electrostatic forces for fabricating continuous ultrafine fibers that offer various advantages such as high surface area and high porosity. Thus, this method has gained interest for use in many fields, especially biomedical fields. This review focuses on researches and studies in electrospinning, PCL, electrospinning of PCL and also biomedical applications of the electrospun PCL fiber mats. Copyright © 2016 John Wiley & Sons, Ltd.     

Lipases and their industrial applications

Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) are part of the family of hydrolases that act on carboxylic ester bonds. The physiologic role of lipases is to hydrolyze triglycerides into diglycerides, monoglycerides, fatty acids, and glycerol. These enzymes are widely found throughout the animal and plant kingdoms, as well as in molds and bacteria. Of all known enzymes, lipases have attracted the most scientific attention. In addition to their natural function of hydrolyzing carboxylic ester bonds, lipases can catalyze esterification, interesterification, and transesterification reactions in nonaqueous media. This versatility makes lipases the enzymes of choice for potential applications in the food, detergent, pharmaceutical, leather, textile, cosmetic, and paper industries. The most significant industrial applications of lipases have been mainly found in the food, detergent, and pharmaceutical sectors. Limitations of the industrial use of these enzymes have mainly been owing to their high production costs, which may be overcome by molecular technologies, enabling the production of these enzymes at high levels and in a virtually purified form.     

基于静电纺丝技术的多级结构聚合物纳米纤维复合材料的研究进展

静电纺丝技术是目前制备纳米纤维最重要的方法之一,以其制备的纤维具有直径可控、比表面积大、孔隙率高等优点,因而被广泛应用于过滤、催化、传感器及生物医学等众多领域.以静电纺丝纤维为模板可进一步构建多级结构的功能性聚合物纳米纤维复合材料,拓宽其应用范围.本文着重概述了近年来基于静电纺丝技术的简单共混型、核壳结构及多级结构的聚合物纳米纤维复合材料的制备、结构及性能,并展望了其应用研究前景.     

Hydroxyethyl curdlan as a novel water soluble derivative: Synthesis,characterization, and antioxidant capacity

In this study, hydroxyethyl curdlans (HeCDs) with different molecular weights were successfully fabricated. The structure and properties of the synthesized HeCDs were measured by FTIR, ¹³C nuclear magnetic resonance (NMR), and Raman spectroscopy and compared with curdlan. The degree of crystallinity of HeCDs was measured with X-ray diffractometry (XRD). Differential scanning calorimetry and thermogravimetric analysis were performed to determine thermal properties of HeCs. Solubility of HeCDs was tested in water, common organic solvents, and NaOH solution. Antioxidant activities of HeCs were investigated using various in vitro assay systems. The HeCDs exhibited a dose-dependent free radical scavenging activity as shown by their DPPH radical, ABTS radical and superoxide anion radical inhibition, and ferrous chelating ability and reducing power. The improved water solubility property and antioxidant activity of these curdlan derivatives could have a wide range of applications, particularly its use as an antioxidant in food, food packaging, biomedical, and pharmaceutical industries.     

Use of bacterial cellulose in the textile industry and the wettability challenge—a review

Bacterial cellulose (BC) has been studied as an alternative material in several segments of the food, pharmaceutical, materials and textile industries. The importance of BC is linked to sustainability goals, since it is an easily degradable biomaterial of low toxicity to the environment and is a renewable raw material. For use in the textile area, bacterial cellulose has attracted great interest from researchers, but it presents some challenges notably to its hydrophilic structure. This integrative review article brings together studies and methods related to minimizing the hydrophilicity of bacterial cellulose, in order to expand its applicability in the textile industry in its dry state. The databases consulted were Scopus, ScienceDirect, ProQuest and Web of Science, the documents investigated were scientific articles and the time period investigated was between 2015 and 2021. The results showed that although there are methods to make the BC membrane more hydrophobic, future studies in this regard and on other properties must continue so that bacterial cellulose can be commercially introduced in the textile sector.

     

Nanoemulsions with Amaranth and Sea Buckthorn Oils

Colloid Journal - Nanoemulsions (NEs) containing natural components are of particular interest for use in the pharmaceutical and food industries, including the encapsulation of hydrophobic...     

Stimuli-responsive electrospun fibers and their applications

Stimuli-responsive electrospun nanofibers are gaining considerable attention as highly versatile tools which offer great potential in the biomedical field. In this critical review, an overview is given on recent advances made in the development and application of stimuli-responsive fibers. The specific features of these electrospun fibers are highlighted and discussed in view of the properties required for the diverse applications. Furthermore, several novel biomedical applications are discussed and the respective advantages and shortcomings inherent to stimuli-responsive electrospun fibers are addressed (136 references).     

Chemical Characteristics and Antioxidant Activity of Arctostaphylos uva-ursi L. Spreng. at the Southern Border of the Geographical Range of the Species in Europe

The bearberry (Arctostaphylos uva-ursi L. Spreng.) is a source of herbal material—bearberry leaf (Uvae ursi folium), which is highly valued and sought by pharmaceutical and cosmetic industries. For many years, leaves of this plant have been used in traditional medicine as a diuretic, antimicrobial, and anti-inflammatory agent for various diseases of the urogenital tract. The bearberry has also been proposed as a natural antioxidant additive due to the high contents of phenolic compounds in its leaves. The study was focused on characterization of the basic phytochemical composition and antioxidant activity of extracts derived from bearberry leaves collected from plants located at the southern border of the geographical range of the species in Europe. The investigated herbal material is characterized by a different chemical profile compared to the chemical profiles of bearberry found in other parts of the continent. Bearberry extracts from plants growing in two different habitat types—heathlands and pine forests showed a wide range of variation, especially in the concentration of hyperoside, corilagin, and methylartutin and the total flavonoid contents. In addition to arbutin, bearberry can be a valuable source of phenolic compounds, which are mainly responsible for the antioxidant properties of extracts. The high content of phenols and high values of antioxidant parameters indicate a high potential of bearberry leaves to be used as a powerful natural source of antioxidants in herbal preparations. Therefore, the A. uva-ursi populations can be a source of plant material for pharmaceutical, cosmetic, and food industries.     

Solvent Influences the Morphology and Mechanical Properties of Electrospun Poly(L-lactic acid) Scaffold for Tissue Engineering Applications

Electrospun micro- and nanofiber scaffolds have gained interest in biomedical applications, especially in tissue engineering, because they can be used to reproduce the structure of the extracellular matrix (ECM) of natural tissue. The selection of the solvent is an important factor which affects the diameter, the surface morphology and the crystallinity of the electrospun fibers, and, accordingly, their mechanical properties as well as their degradation kinetics. Furthermore, the surface morphology of the electrospun fibres can be controlled by solvent vapour pressure to produce porous structures which might be helpful for cell adhesion and proliferation. In the present work, poly (L-lactic acid) (PLLA) has been electrospun using solvents with different vapour pressures to investigate the influences of the solvent vapour pressure on morphology, diameter, crystallinity and mechanical properties of the electrospun fiber scaffolds. The results show that the vapour pressure of the solvents (or solvent mixtures) play an important role in the fiber diameter and crystallinity. Furthermore, the crystallinity of the fibers is increased by lowering the vapour pressure of the used solvent. In addition, the mechanical properties (e.g., tensile strength and Young's modulus) are strongly dependent on morphological features such average fibers diameter. The smaller the average diameter, the higher the tensile strength and Young's modulus.     

ELECTROSPRAYING/ELECTROSPINNING OF POLY(γ-STEARYL-L-GLUTAMATE): FORMATION OF SURFACES WITH SUPERHYDROPHOBICITY

  Electrospraying/electrospinning of poly(γ-stearyl-L-glutamate) (PSLG) was investigated on a series solutions with different concentrations in chloroform. Field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) were used to characterize the morphology and structure of the electrosprayed/electrospun polypeptide mats. It was found that electrospraying of PSLG with concentrations lower than 16 wt% afforded beads, while microfibers could be electrospun at the concentration of 22 wt%. The hydrophobicity of the electrosprayed/electrospun PSLG mats was investigated with static water contact angle (WCA) and tilt angle measurements. It was demonstrated that the superhydrophobic surfaces of PSLG with WCAs and tilt angles in the ranges of 150°-170° and 16.5°-4.2°, respectively, were obtained through electrospraying/electrospinning process.     

Structured emulsion-based delivery systems: Controlling the digestion and release of lipophilic food components

There is a need for edible delivery systems to encapsulate, protect and release bioactive and functional lipophilic constituents within the food and pharmaceutical industries. These delivery systems could be used for a number of purposes: controlling lipid bioavailability; targeting the delivery of bioactive components within the gastrointestinal tract; and designing food matrices that delay lipid digestion and induce satiety. Emulsion technology is particularly suited for the design and fabrication of delivery systems for lipids. In this article we provide an overview of a number of emulsion-based technologies that can be used as edible delivery systems by the food and other industries, including conventional emulsions, nanoemulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems can be produced from food-grade (GRAS) ingredients (e.g., lipids, proteins, polysaccharides, surfactants, and minerals) using relatively simple processing operations (e.g., mixing, homogenizing, and thermal processing). The structure, preparation, and utilization of each type of delivery system for controlling lipid digestion are discussed. This knowledge can be used to select the most appropriate emulsion-based delivery system for specific applications, such as encapsulation, controlled digestion, and targeted release.     

Functionalization of chitosan polymer and their applications

The deacetylated derivative of chitin i.e. chitosan is an advantageous and interesting bioactive polymer. Despite its biodegradability, it consists of many reactive primary and secondary hydroxyl (–OH) and amino (–NH₂) functional groups which allow the possibilities of chemical modifications. The several chemical modifications such as alkylation, acylation, quaternization, phthaloylation, sulfation, thiolation, carboxymethylation, graft copolymerization etc. carried out. The chemical modification results various types of derivatives with modified properties for specific applications in varied area mainly of pharmaceutical, biomedical, biotechnological, cosmetic, agricultural, food and non-food industries as well as in water treatment, paper, and textile industry. The ability of chitosan to undergo versatile modifications and applications presents a great opportunity to scientific community and to industry.     

Determination of the degree of N-deacetylation in chitin and chitosan as well as their monomer sugar ratios by near infrared spectroscopy

Chitin and its derivative chitosan are rapidly becoming of commercial interest in the biomedical, wastewater treatment, and fiber industries. One of the most important properties of these copolymers is the degree of N-acetylation. Presently there is no rapid accurate method to determine this value. We propose near infrared spectroscopy for such a method. Using a primary method such as hydrobromic acid titration or ¹H-NMR, standards can be established. Once a model calibration equation has been developed, unknown samples can be analyzed by near infrared spectroscopy in less than 5 min. This is demonstrated by examining representative structural monomers of chitosan, N-acetyl-D-glucosamine and D-glucosamine hydrochloride, as model compounds as well as actual chitin and chitosan samples. © 1993 John Wiley & Sons, Inc.