An alternative way to encapsulate probiotics within electrospun alginate nanofibers as monitored under simulated gastrointestinal conditions and in kefir

Decorating Bacteria with a Therapeutic Nanocoating for Synergistically Enhanced Biotherapy

Disorders in the gut microbiota have been implicated in various diseases, such as inflammatory bowel diseases, diabetes, and cancers. Oral microecologics are of great importance due to their ability to directly intervene the gut microbiome as well as their noninvasiveness and low side effects, while have suffered from low bioavailability and a single therapeutic effect. Here, probiotics are coated with a therapeutic nanocoating for synergistically enhanced biotherapy, a method inspired by the robust protective and therapeutic effectiveness of silkworm cocoon. With its transition from a random coil to β-sheet conformation, silk fibroin can self-assemble onto the surface of bacteria. By a simple layer-by-layer procedure, an entire nanocoating can be formed along with a near quantitative coating ratio and almost uninfluenced bacterial viability. Thanks to its protective barrier role and innate pharmaceutical activity, silk fibroin nanocoating endows the coated bacteria with a markedly improved survival against gastric insults and a synergistically enhanced therapeutic effect in a murine model of intestinal mucositis. This work demonstrates how therapeutic elements can be combined with probiotics via a simple coating strategy and proposes an alternative to enhance bioavailability and treatment efficacy of oral microecologics.

Encapsulation of Pharmaceutical and Nutraceutical Active Ingredients Using Electrospinning Processes

Electrospinning is an inexpensive and powerful method that employs a polymer solution and strong electric field to produce nanofibers. These can be applied in diverse biological and medical applications. Due to their large surface area, controllable surface functionalization and properties, and typically high biocompatibility electrospun nanofibers are recognized as promising materials for the manufacturing of drug delivery systems. Electrospinning offers the potential to formulate poorly soluble drugs as amorphous solid dispersions to improve solubility, bioavailability and targeting of drug release. It is also a successful strategy for the encapsulation of nutraceuticals. This review aims to briefly discuss the concept of electrospinning and recent progress in manufacturing electrospun drug delivery systems. It will further consider in detail the encapsulation of nutraceuticals, particularly probiotics.

Microencapsulation of Bioactive Ingredients for Their Delivery into Fermented Milk Products: A Review

The popularity and consumption of fermented milk products are growing. On the other hand, consumers are interested in health-promoting and functional foods. Fermented milk products are an excellent matrix for the incorporation of bioactive ingredients, making them functional foods. To overcome the instability or low solubility of many bioactive ingredients under various environmental conditions, the encapsulation approach was developed. This review analyzes the fortification of three fermented milk products, i.e., yogurt, cheese, and kefir with bioactive ingredients. The encapsulation methods and techniques alongside the encapsulant materials for carotenoids, phenolic compounds, omega-3, probiotics, and other micronutrients are discussed. The effect of encapsulation on the properties of bioactive ingredients themselves and on textural and sensory properties of fermented milk products is also presented.

Encapsulating bacteria in alginate-based electrospun nanofibers

Encapsulation technologies are imperative for the safe delivery of live bacteria into the gut where they regulate bodily functions and human health. In this study, we develop alginate-based nanofibers that could potentially serve as a biocompatible, edible probiotic delivery system. By systematically exploring the ratio of three components, the biopolymer alginate (SA), the carrier polymer poly(ethylene oxide) (PEO), and the FDA approved surfactant polysorbate 80 (PS80), the surface tension and conductivity of the precursor solutions were optimized to electrospin bead-free fibers with an average diameter of 167 ± 23 nm. Next, the optimized precursor solution (2.8/1.2/3 wt% of SA/PEO/PS80) was loaded with Escherichia coli (E. coli, 108 CFU mL-1), which served as our model bacterium. We determined that the bacteria in the precursor solution remained viable after passing through a typical electric field (∼1 kV cm-1) employed during electrospinning. This is because the microbes are pulled into a sink-like flow, which encapsulates them into the polymer nanofibers. Upon electrospinning the E. coli-loaded solutions, beads that were much smaller than the size of an E. coli were initially observed. To compensate for the addition of bacteria, the SA/PEO/PS80 weight ratio was reoptimized to be 2.5/1.5/3. Smooth fibers with bulges around the live microbes were formed, as confirmed using fluorescence and scanning electron microscopy. By dissolving and plating the nanofibers, we found that 2.74 × 105 CFU g-1 of live E. coli cells were contained within the alginate-based fibers. This work demonstrates the use of electrospinning to encapsulate live bacteria in alginate-based nanofibers for the potential delivery of probiotics to the gut.

Nanomaterial-based encapsulation for controlled gastrointestinal delivery of viable probiotic bacteria

Probiotics are microorganisms that have beneficial health effects when administered in adequate dosages. The oral administration of probiotic bacteria is widely considered beneficial for both intestinal as well as systemic health but its clinical efficacy is conflicted in the literature. This may at least in part be due to the loss of viability during gastrointestinal passage resulting in poor intestinal delivery. Microencapsulation technology has been proposed as a successful strategy to address this problem by maintaining the viability of probiotics, thereby improving their efficacy following oral administration. More recently, nanomaterials have demonstrated significant promise as encapsulation materials to improve probiotic encapsulation. The integration of nanotechnology with microencapsulation techniques can improve the controlled delivery of viable probiotic bacteria to the gut. The current review aims at summarizing the types of nanomaterials used for the microencapsulation of probiotics and showing how they can achieve the delivery and controlled release of probiotics at the site of action.

Insights on the Critical Parameters Affecting the Probiotic Viability During Stabilization Process and Formulation Development

Probiotics have gained a lot of interest in recent years as an alternative as well as adjuvant therapy for several conditions owing to their health benefits. These live microorganisms have proven efficacy for treating gut disorders, inflammation, bacterial vaginosis, hepatic and depressive disorders, and many more. There are conventional as well as non-conventional formulations available for the delivery of probiotics with the latter having fewer regulatory guidelines. The conventional formulations include the pharmaceutical formulations specifically designed to deliver an efficacious number of viable microorganisms. Studies have indicated 10⁸-10⁹ CFU/g as an ideal dose of probiotics for achieving health benefits, and hence, all the formulations must at least contain the said number of viable bacteria to show a therapeutic effect. The most crucial feature of probiotic formulations is that the bacteria are prone to several environmental and processing factors which all together reduce the viability of the bacteria in the final formulation. These factors include processing parameters like temperature, humidity, pressure, and storage conditions. Thus, the present review primarily focuses on the critical process parameters affecting the probiotic viability during stabilization process and formulation development. Understanding these factors prior to processing helps in delivering probiotics in the required therapeutic numbers at the target site.

Perspective on Constructing Cellulose-Hydrogel-Based Gut-Like Bioreactors for Growth and Delivery of Multiple-Strain Probiotic Bacteria

The current perspective presents an outlook on developing gut-like bioreactors with immobilized probiotic bacteria using cellulose hydrogels. The innovative concept of using hydrogels to simulate the human gut environment by generating and maintaining pH and oxygen gradients in the gut-like bioreactors is discussed. Fundamentally, this approach presents novel methods of production as well as delivery of multiple strains of probiotics using bioreactors. The relevant existing synthesis methods of cellulose hydrogels are discussed for producing porous hydrogels. Harvesting methods of multiple strains are discussed in the context of encapsulation of probiotic bacteria immobilized on cellulose hydrogels. Furthermore, we also discuss recent advances in using cellulose hydrogels for encapsulation of probiotic bacteria. This perspective also highlights the mechanism of probiotic protection by cellulose hydrogels. Such novel gut-like hydrogel bioreactors will have the potential to simulate the human gut ecosystem in the laboratory and stimulate new research on gut microbiota.

Improved digestive stability of probiotics encapsulated within poly(vinyl alcohol)/cellulose acetate hybrid fibers

Novel cellulose acetate (CA) and poly(vinyl alcohol) (PVA) hybrid fibers, fabricated via angled dual-nozzle electrospinning, were used for the encapsulation of probiotics to enhance their gastrointestinal stability. In this study, Escherichia coli strain Nissle 1917 (EcN) cells were encapsulated within PVA/CA composite mats, where CA enhanced the bacterial stability under gastric conditions and PVA provided protection against the toxic solvent during the electrospinning process. Scanning electron microscopy images revealed that EcN was successfully encapsulated within the hybrid fibers. In the simulated digestive system, free cells lost their viability within 100 min, whereas PVA/CA-encapsulated cells survived with a final count of 3.9 log CFU/mL (from an initial count of 7.8 log CFU/mL), an increase of 1 log CFU/mL compared with those in PVA/PVA fibers. Considering the enhanced viability of the encapsulated cells in the gastrointestinal system, multi-nozzle electrospinning is a promising technique for the fabrication of novel matrices for probiotic encapsulation.

Nano-technological approaches for plant and marine-based polysaccharides for nano-encapsulations and their applications in food industry

Novel food preservation methods, along with preservatives have been employed to prevent food products from spoilage. There is an increasing demand to substitute synthetic preservatives with natural bioactive compounds since they are safe and environmentally friendly. Bioactive compounds with functional and therapeutic properties are found in foods and have also beneficial physiological and immunological health effects. However, there are some issues associated with bioactive compounds, such as low stability, solubility, and permeability. Encapsulation techniques, especially nano-encapsulation, are a promising technique to overcome these restrictions. A range of the plants' constituents can be converted into bio-nanomaterials. Major plant constituents are polysaccharides which have good biocompatibility properties and therapeutic activities, such as antioxidant, antiviral, anti-inflammatory, anti-allergic, and anti-tumor. Among plant and marine-based polysaccharides, cellulose, starch, alginates, chitosan, and carrageenans have been used as carrier materials to preserve core material. Moreover, many studies indicated that favorable sources such as plant and marine based polysaccharides are emerging. This chapter will cover plant and marine-based polysaccharides for nano-encapsulation and their application in the food industry.

A sandwich structured drug delivery composite membrane for improved recovery after spinal cord injury under longtime controlled release

A sandwich structured composite membrane for longtime controlled release of nerve growth factor (NGF) to repair spinal cord injury (SCI) is prepared through electrospray. In this system, PLA film is used as the sealing layer to prevent drug diffusion and provide mechanical support, PLGA microspheres as the sandwich layer to load and controlled release NGF, and chitosan (CS) film as the planting layer to seed bone marrow mesenchymal stem cells (BMSCs). The composite membrane has good biocompatibility and can effectively promote PC-12 cells to differentiate into neurons. In addition, the composite membrane can be directly applied to the injured areas without further damage. The longtime sustained release of NGF guaranteed enough requirement time for SCI repair, which will decrease the administration frequency and improve patient compliance. The administration of BMSCs coupled with the sandwich composite membrane effectively relieves SCI, decreases cavity formation, enhances neuronal regeneration and tissue repair, as well as improves the recovery of locomotor functions. Overall, this present work provides a future perspective for the treatment of SCI by the NGF-loaded sandwich composite membrane with prolonged drug release function.