Biopolymer-based nanoparticles and microparticles: Fabrication, characterization, and application

Delivery by Design (DbD): A Standardized Approach to the Development of Efficacious Nanoparticle- and Microparticle-Based Delivery Systems

The design and development of nanoparticle- and microparticle-based delivery systems for the encapsulation, protection, and controlled release of active agents has grown considerably in the agrochemical, cosmetic, food, personal care, and pharmaceutical industries. These colloidal delivery systems can be utilized to overcome problems such as poor solubility, low activity, and chemical instability of active agents, as well as to create novel functional attributes such as controlled or targeted delivery. The purpose of this article is to develop a systematic approach, referred to as "delivery-by-design" (DbD), to make the design and fabrication process more efficient and effective. Initially, a brief review of some of the challenges associated with incorporating active agents into commercial products is given, and then an overview of different kinds of simple and complex colloidal delivery systems is given. The DbD approach is then presented as a series of stages: (1) definition of the molecular and physicochemical properties of the active agent; (2) definition of the required physicochemical, sensory, and functional attributes of the end-product; (3) specification of the required attributes of the colloidal delivery system; (4) specification of particle properties and delivery system selection; (5) optimization of delivery system manufacturing process; (6) establishment and implementation of delivery system testing protocol; and (7) optimization of delivery system performance. Utilization of the DbD approach may lead to more rapid design of efficacious and economically viable colloidal delivery systems for commercial applications.

Microencapsulation of Eugenia uniflora L. juice by spray drying using fructans with different degrees of polymerisation

The objective of this work was to microencapsulate pitanga (Eugenia uniflora L.) juice by spray drying, using High Performance Agave Fructans (HPAF) and High Degree of Polymerisation Agave Fructans (HDPAF) and maltodextrin (MD), respectively, as the wall materials. The physicochemical and antioxidant properties of the capsules during storage at various temperatures were evaluated. The microparticles developed using fructans HPAF and HDPAF, exhibited similar physicochemical and flow properties to those presented by the microparticles prepared with MD. The highest yield and concentration of anthocyanins after drying and during storage were found for a 1:6 core:wall material ratio. The total color change was a good indicator of the microcapsule stability. This study showed that both fructans fraction possess similar encapsulating properties to MD and that the HDPAF were more efficacious than MD at protecting the antioxidants during drying and storage.

Hydrogels for Biomedical Applications: Cellulose, Chitosan, and Protein/Peptide Derivatives

Hydrogels based on polysaccharide and protein natural polymers are of great interest in biomedical applications and more specifically for tissue regeneration and drug delivery. Cellulose, chitosan (a chitin derivative), and collagen are probably the most important components since they are the most abundant natural polymers on earth (cellulose and chitin) and in the human body (collagen). Peptides also merit attention because their self-assembling properties mimic the proteins that are present in the extracellular matrix. The present review is mainly focused on explaining the recent advances on hydrogels derived from the indicated polymers or their combinations. Attention has also been paid to the development of hydrogels for innovative biomedical uses. Therefore, smart materials displaying stimuli responsiveness and having shape memory properties are considered. The use of micro- and nanogels for drug delivery applications is also discussed, as well as the high potential of protein-based hydrogels in the production of bioactive matrices with recognition ability (molecular imprinting). Finally, mention is also given to the development of 3D bioprinting technologies.

Synthesis of silver nanoparticles using bacterial exopolysaccharide and its application for degradation of azo-dyes

In this study, the synthesis and characterization of exopolysaccharide-stabilized sliver nanoparticles (AgNPs) was carried out for the degradation of industrial textile dyes. Characterization of AgNPs was done using surface plasmon spectra using UV-Vis spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy. The morphological nature of AgNPs was determined through transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM), which indicated that the AgNPs were spherical in shape, with an average size of 35 nm. The thermal behaviour of AgNPs revealed that it is stable up to 437.1 °C and the required energy is 808.2J/g in TGA-DTA analysis. Ability of EPS stabilized AgNPs for degradation of azo dyes such as Methyl orange (MO) and Congo red (CR) showed that EPS stabilized AgNPs were found to be efficient in facilitating the degradation process of industrial textile dyes. The electron transfer takes place from reducing agent to dye molecule via nanoparticles, resulting in the destruction of the dye chromophore structure. This makes EPS-AgNPs a suitable, cheap and environment friendly candidate for biodegradation of harmful textile dyes.

Micro- and nano bio-based delivery systems for food applications: In vitro behavior

Micro- and nanoencapsulation is an emerging technology in the food field that potentially allows the improvement of food quality and human health. Bio-based delivery systems of bioactive compounds have a wide variety of morphologies that influence their stability and functional performance. The incorporation of bioactive compounds in food products using micro- and nano-delivery systems may offer extra health benefits, beyond basic nutrition, once their encapsulation may provide protection against undesired environmental conditions (e.g., heat, light and oxygen) along the food chain (including processing and storage), thus improving their bioavailability, while enabling their controlled release and target delivery. This review provides an overview of the bio-based materials currently used for encapsulation of bioactive compounds intended for food applications, as well as the main production techniques employed in the development of micro- and nanosystems. The behavior of such systems and of bioactive compounds entrapped into, throughout in vitro gastrointestinal systems, is also tracked in a critical manner. Comparisons between various in vitro digestion systems (including the main advantages and disadvantages) currently in use, as well as correlations between the behavior of micro- and nanosystems studied through in vitro and in vivo systems were highlighted and discussed here for the first time. Finally, examples of bioactive micro- and nanosystems added to food simulants or to real food matrices are provided, together with a revision of the main challenges for their safe commercialization, the regulatory issues involved and the main legislation aspects.

Formulation, Characterization and Properties of Hemp Seed Oil and Its Emulsions

The formulation, characterization, and anticipated antibacterial properties of hemp seed oil and its emulsions were investigated. The oil obtained from the seeds of Cannabis sativa L. in refined and unrefined form was characterized using iodine, saponification, acid values, and gas chromatography, and was employed for the preparation of stable oil-in-water emulsions. The emulsions were prepared using pairs of non-ionic surfactants (Tween, Span). The effects of the emulsification method (spontaneous emulsification vs. high-intensity stirring), hydrophilic lipophilic balance (HLB), type and concentration of surfactant, and oil type on the size and distribution of the emulsion particles were investigated. It was found that the ability to form stable emulsions with small, initial particle sizes is primarily dependent on the given method of preparation and the HLB value. The most efficient method of emulsification that afforded the best emulsions with the smallest particles (151 ± 1 nm) comprised the high-energy method, and emulsions stable over the long-term were observed at HBL 9 with 10 wt % concentration of surfactants. Under high-intensity emulsification, refined and unrefined oils performed similarly. The oils as well as their emulsions were tested against the growth of selected bacteria using the disk diffusion and broth microdilution methods. The antibacterial effect of hemp seed oil was documented against Micrococcus luteus and Staphylococcus aureus subsp. aureus. The formulated emulsions did not exhibit the antibacterial activity that had been anticipated.

Incorporation of PLLA micro-fillers for mechanical reinforcement of calcium-phosphate cement

Calcium phosphate cements (CPCs) are biocompatible, resorbable, injectable and osteoconductive. Those properties render such materials suitable for applications where bone repair and regeneration is required However, their brittle nature limits their application only to non-load-bearing applications. The incorporation of long polymeric fibers can improve the mechanical properties of CPCs, but aggregation is a major problem. Instead, short polymeric fillers can be easily dispersed in the cement matrix, but their reinforcing effect has not been studied yet. In this study, continuous poly-_L-lactic acid fibers (PLLA) with a smooth or porous surface morphology were prepared by electrospinning. PLLA micro-fillers were developed, by means of an aminolysis process, and added to α-TCP or α-TCP/PLGA-based cements. Micro-filler distribution as well as the morphology, cohesiveness, setting times and mechanical properties were evaluated. PLLA micro-fillers were homogeneously dispersed throughout the cement while the handling properties were not significantly affected. A decrease in the initial setting times was observed when PLLA was added, while the mechanical properties were comparable to those of the α-TPC or α-TCP/PLGA compositions.

Design of experiments for microencapsulation applications: A review

Microencapsulation techniques have been intensively explored by many research sectors such as pharmaceutical and food industries. Microencapsulation allows to protect the active ingredient from the external environment, mask undesired flavours, a possible controlled release of compounds among others. The purpose of this review is to provide a background of design of experiments in microencapsulation research context. Optimization processes are required for an accurate research in these fields and therefore, the right implementation of micro-sized techniques at industrial scale. This article critically reviews the use of the response surface methodologies in pharmaceutical and food microencapsulation research areas. A survey of optimization procedures in the literature, in the last few years is also presented.

β-Lactoglobulin: An efficient nanocarrier for advanced delivery systems

Thanks to the progress of nanotechnology there are several agent-delivery systems that can be selected to achieve rapid and specific delivery of a wide variety of biologically active agents. Consequently, the manipulation and engineering of biopolymers has become one of the most exciting subjects for those who study delivery systems on the nanoscale. In this regard, both nanoparticle formation and a carrier role have been observed in the case of the globular milk whey protein, β-lactoglobulin (β-LG), setting it apart from many other proteins. To date, many efforts adopting different approaches have created β-LG nanoparticles useful in forming delivery systems for various agents with specific targets. In this review, the potential of β-LG to play the role of an efficient and diverse carrier protein, as well as its ability to form a well-targeted nano-scale delivery system is discussed.

Designing biopolymer microgels to encapsulate, protect and deliver bioactive components: Physicochemical aspects

Biopolymer microgels have considerable potential for their ability to encapsulate, protect, and release bioactive components. Biopolymer microgels are small particles (typically 100nm to 1000μm) whose interior consists of a three-dimensional network of cross-linked biopolymer molecules that traps a considerable amount of solvent. This type of particle is also sometimes referred to as a nanogel, hydrogel bead, biopolymer particles, or microsphere. Biopolymer microgels are typically prepared using a two-step process involving particle formation and particle gelation. This article reviews the major constituents and fabrication methods that can be used to prepare microgels, highlighting their advantages and disadvantages. It then provides an overview of the most important characteristics of microgel particles (such as size, shape, structure, composition, and electrical properties), and describes how these parameters can be manipulated to control the physicochemical properties and functional attributes of microgel suspensions (such as appearance, stability, rheology, and release profiles). Finally, recent examples of the utilization of biopolymer microgels to encapsulate, protect, or release bioactive agents, such as pharmaceuticals, nutraceuticals, enzymes, flavors, and probiotics is given.

Nanotechnology Approaches for Increasing Nutrient Bioavailability

Health-promoting ingredients such as phenolic compounds, vitamins, and minerals are being increasingly introduced into foods and beverages to produce "functional foods" specifically designed to improve human health, well-being, and performance. However, it is often challenging to incorporate these nutraceuticals into foods because they have poor solubility characteristics, impart undesirable flavor profiles, are chemically unstable, or have low bioavailability. This problem can often be overcome by encapsulating the bioactive components in nanoparticle-based delivery systems. The bioavailability of encapsulated bioactive agents often increases when the size of the particles containing them decreases, due to their faster digestion, ability to penetrate the mucus layer, or direct uptake by cells. Nanoparticles can be formulated to survive passage through specific regions of the gastrointestinal tract and then release their payload at a specified point, thus maximizing their potential health benefits. Nutraceutical-loaded nanoparticles can be fabricated through lipid formulations, natural nanocarriers, specialized equipment, biopolymer nanoparticles, and miscellaneous techniques. Classification into these five groups is based on the main mechanism or ingredient used to fabricate the nanoparticles. This chapter focuses on the utilization of food-grade nanoparticles for improving the performance of nutraceuticals in functional foods and beverages.

Enzyme-Based Strategies for Structuring Foods for Improved Functionality

Enzyme technologies can be used to create food dispersions with novel functional attributes using structural design principles. Enzymes that utilize food-grade proteins and/or polysaccharides as substrates have gained recent interest among food scientists. The utilization of enzymes for structuring foods is an ecologically and economically viable alternative to the utilization of chemical cross-linking and depolymerization agents. This review highlights recent progress in the use of enzymes to modify food structures, particularly the interfacial and/or bulk properties of food dispersions with special emphasis on commercially available enzymes. Cross-linking enzymes such as transglutaminase and laccase promote the formation of intra- and intermolecular bonds between biopolymers to improve stability and functionality, whereas various degrading enzymes such as proteases alter the native conformation of proteins, leading to self-assembly of hierarchically ordered colloids. Results of this bio-inspired approach show that rational use of structure-affecting enzymes may enable food manufacturers to produce food dispersions with improved physical, functional, textural, and optical properties.

Magnetization of eugenol to fabricate magnetic-responsive emulsions for targeted delivery of caffeic acid phenethyl ester

The manipulative colloidal vehicles with appreciable stability were fabricated by rice proteins under an eco-friendly, cross-linkage free environment, which can be tailored for targeted delivery of diagnostic or curative drugs.

Light-responsive molecular containers

This review highlights relevant studies of light-controlled molecular containers able to catch and release small molecules.

Structural design approaches for creating fat droplet and starch granule mimetics

This article focuses on hydrogel-based strategies for creating reduced calorie foods with desirable physicochemical, sensory, and nutritional properties.

Nanobiomaterials' applications in neurodegenerative diseases

The blood-brain barrier is the interface between the blood and brain, impeding the passage of most circulating cells and molecules, protecting the latter from foreign substances, and maintaining central nervous system homeostasis. However, its restrictive nature constitutes an obstacle, preventing therapeutic drugs from entering the brain. Usually, a large systemic dose is required to achieve pharmacological therapeutic levels in the brain, leading to adverse effects in the body. As a consequence, various strategies are being developed to enhance the amount and concentration of therapeutic compounds in the brain. One such tool is nanotechnology, in which nanostructures that are 1-100 nm are designed to deliver drugs to the brain. In this review, we examine many nanotechnology-based approaches to the treatment of neurodegenerative diseases. The review begins with a brief history of nanotechnology, followed by a discussion of its definition, the properties of most reported nanomaterials, their biocompatibility, the mechanisms of cell-material interactions, and the current status of nanotechnology in treating Alzheimer's, Parkinson's diseases, and amyotrophic lateral sclerosis. Of all strategies to deliver drug to the brain that are used in nanotechnology, drug release systems are the most frequently reported.

Calcium-alginate microparticles for sustained release of catechin prepared via an emulsion gelation technique

Catechin-loaded Ca-alginate beads and microparticles were prepared by an emulsion gelation method using sunflower oil for efficient sustained release of catechin. The emulsion was prepared by sequential mixing of alginate, oil, and oleic acid ester as an emulsifier. Encapsulation efficiency (EE) and inhibition of catechin release of the beads were significantly increased approximately to 453.83 and 148.71% by the emulsion gelation technique, respectively (p<0.05). For the microparticles, the highest inhibition of catechin release after 1 h of incubation (78.82%) was observed at the microparticles prepared by 5% (w/w) oil, 3% (w/w) alginate, 4% (w/v) CaCl₂, and 200 mg catechin with the most hydrophilic emulsifier, decaglycerol mono-ester. Moreover, the catechin release was sustained at acidic conditions and increased with increase in pH of release medium. These results suggest that catechin encapsulation within Ca-alginate particles by emulsion gelation method can be an effective delivery system for catechin.