Colon-targeted delivery systems for nutraceuticals: A review of current vehicles, evaluation methods and future prospects

Docosahexaenoic acid-loaded nanoparticles: A state-of-the-art of preparation methods, characterization, functionality, and therapeutic applications

Docosahexaenoic acid (DHA, C22:6 n-3), an omega-3 polyunsaturated fatty acid, offers several beneficial effects. DHA helps in reducing depression, autoimmune diseases, rheumatoid arthritis, attention deficit hyperactivity syndrome, and cardiovascular diseases. It can stimulate the development of brain and nerve, alleviate lipids metabolism-related disorders, and enhance vision development. However, DHA susceptibility to chemical oxidation, poor water solubility, and unpleasant order could restrict its applications for nutritional and therapeutic purposes. To avoid these drawbacks and enhance its bioavailability, DHA can be encapsulated using an effective delivery system. Several encapsulation methods are recognized, and DHA-loaded nanoparticles have demonstrated numerous benefits. In clinical studies, positive influences on the development of several diseases have been reported, but some assumptions are conflicting and need more exploration, since DHA has a systemic and not a targeted release at the required level. This might cause the applications of nanoparticles that could allow DHA release at the required level and improve its efficiency, thus resulting in a better controlling of several diseases. In the current review, we focused on researches investigating the formulation and development of DHA-loaded nanoparticles using different delivery systems, including low-density lipoprotein, zinc oxide, silver, zein, and resveratrol-stearate. Silver-DHA nanoparticles presented a typical particle size of 24 nm with an incorporation level of 97.67 %, while the entrapment efficiency of zinc oxide-DHA nanoparticles represented 87.3 %. By using zein/Poly (lactic-co-glycolic acid) stabilized nanoparticles, DHA's encapsulation level reached 84.6 %. We have also highlighted the characteristics, functionality and medical implementation of these nanoparticles in the treatment of inflammations, brain disorders, diabetes as well as hepatocellular carcinoma.

Oral delivery of probiotics using single-cell encapsulation

Adequate intake of live probiotics is beneficial to human health and wellbeing because they can help treat or prevent a variety of health conditions. However, the viability of probiotics is reduced by the harsh environments they experience during passage through the human gastrointestinal tract (GIT). Consequently, the oral delivery of viable probiotics is a significant challenge. Probiotic encapsulation provides a potential solution to this problem. However, the production methods used to create conventional encapsulation technologies often damage probiotics. Moreover, the delivery systems produced often do not have the required physicochemical attributes or robustness for food applications. Single-cell encapsulation is based on forming a protective coating around a single probiotic cell. These coatings may be biofilms or biopolymer layers designed to protect the probiotic from the harsh gastrointestinal environment, enhance their colonization, and introduce additional beneficial functions. This article reviews the factors affecting the oral delivery of probiotics, analyses the shortcomings of existing encapsulation technologies, and highlights the potential advantages of single-cell encapsulation. It also reviews the various approaches available for single-cell encapsulation of probiotics, including their implementation and the characteristics of the delivery systems they produce. In addition, the mechanisms by which single-cell encapsulation can improve the oral bioavailability and health benefits of probiotics are described. Moreover, the benefits, limitations, and safety issues of probiotic single-cell encapsulation technology for applications in food and beverages are analyzed. Finally, future directions and potential challenges to the widespread adoption of single-cell encapsulation of probiotics are highlighted.

S/O/W Emulsion with CAPE Ameliorates DSS-Induced Colitis by Regulating NF-κB Pathway, Gut Microbiota and Fecal Metabolome in C57BL/6 Mice

Inflammatory bowel disease (IBD) has attracted much attention worldwide due to its prevalence. In this study, the effect of a solid-in-oil-in-water (S/O/W) emulsion with Caffeic acid phenethyl ester (CAPE, a polyphenolic active ingredient in propolis) on dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice was evaluated. The results showed that CAPE-emulsion could significantly alleviate DSS-induced colitis through its effects on colon length, reduction in the disease activity index (DAI), and colon histopathology. The results of ELISA and Western blot analysis showed that CAPE-emulsion can down-regulate the excessive inflammatory cytokines in colon tissue and inhibit the expression of p65 in the NF-κB pathway. Furthermore, CAPE-emulsion promoted short-chain fatty acids production in DSS-induced colitis mice. High-throughput sequencing results revealed that CAPE-emulsion regulates the imbalance of gut microbiota by enhancing diversity, restoring the abundance of beneficial bacteria (such as Odoribacter), and suppressing the abundance of harmful bacteria (such as Afipia, Sphingomonas). The results of fecal metabolome showed that CAPE-emulsion restored the DSS-induced metabolic disorder by affecting metabolic pathways related to inflammation and cholesterol metabolism. These research results provide a scientific basis for the use of CPAE-emulsions for the development of functional foods for treating IBD.

Optical sensing for real-time detection of food-borne pathogens in fresh produce using machine learning

Contaminated fresh produce remains a prominent catalyst for food-borne illnesses, prompting the need for swift and precise pathogen detection to mitigate health risks. This paper introduces an innovative strategy for identifying food-borne pathogens in fresh produce samples from local markets and grocery stores, utilizing optical sensing and machine learning. The core of our approach is a photonics-based sensor system, which instantaneously generates optical signals to detect pathogen presence. Machine learning algorithms process the copious sensor data to predict contamination probabilities in real time. Our study reveals compelling results, affirming the efficacy of our method in identifying prevalent food-borne pathogens, including Escherichia coli (E. coli) and Salmonella enteric, across diverse fresh produce samples. The outcomes underline our approach's precision, achieving detection accuracies of up to 95%, surpassing traditional, time-consuming, and less accurate methods. Our method's key advantages encompass real-time capabilities, heightened accuracy, and cost-effectiveness, facilitating its adoption by both food industry stakeholders and regulatory bodies for quality assurance and safety oversight. Implementation holds the potential to elevate food safety and reduce wastage. Our research signifies a substantial stride toward the development of a dependable, real-time food safety monitoring system for fresh produce. Future research endeavors will be dedicated to optimizing system performance, crafting portable field sensors, and broadening pathogen detection capabilities. This novel approach promises substantial enhancements in food safety and public health.

Study of PEG-b-PLA/Eudragit S100 Blends on the Nanoencapsulation of Indigo Carmine Dye and Application in Controlled Release

A nanocapsule shell of poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) mixed with anionic Eudragit S100 (90/10% w/w) was previously used to entrap and define the self-assembly of indigo carmine (IC) within the hydrophilic cavity core. In the present work, binary blends were prepared by solution mixing at different PEG-b-PLA/Eudragit S100 ratios (namely, 100/0, 90/10, 75/25, and 50/50% w/w) to elucidate the role of the capsule shell in tuning the encapsulation of the anionic dye (i.e., IC). The results showed that the higher content of Eudragit S100 in the blend decreases the miscibility of the two polymers due to weak intermolecular interactions between PEG-b-PLA and Eudragit S100. Moreover, with an increase in the amount of Eudragit S100, a higher thermal stability was observed related to the mobility restriction of PEG-b-PLA chains imposed by Eudragit S100. Formulations containing 10 and 25% Eudragit S100 exhibited an optimal interplay of properties between the negative surface charge and the miscibility of the polymer blend. Therefore, the anionic character of the encapsulating agent provides sufficient accumulation of IC molecules in the nanocapsule core, leading to dye aggregates following the self-assembly. At the same time, the blending of the two polymers tunes the IC release properties in the initial stage, achieving slow and controlled release. These findings give important insights into the rational design of polymeric nanosystems containing organic dyes for biomedical applications.

Filamentous fungal pellets as a novel and sustainable encapsulation matrix for exogenous bioactive compounds

Edible filamentous fungi (FF) are considered sustainable food materials given their rich nutrient profile and low carbon and water footprints during production. The current study evaluated FF biomass as a natural encapsulation system for exogenous bioactive compounds and as a model system to investigate the complex food matrix-micronutrient interactions during in vitro digestion. Our objective was to compare the fungal pellet, as a multicellular encapsulation system, with single yeast cell-based carriers in terms of loading and release of curcumin, a model compound. The results suggest that the curcumin encapsulation efficiency was similar in single yeast cells and fungal hyphal cells. A vacuum treatment used to facilitate the infusion of curcumin into yeast or fungal cells also enabled rapid internalization of yeast cells into the fungal pellet matrix. Compared to the single-cell encapsulation system, the multicellular systems modified the release kinetics of curcumin during in vitro digestion by eliminating the initial rapid release and reducing the overall release rate of curcumin in the small intestinal phase. These results provide a deeper understanding of the effect of natural edible structures on the bioaccessibility of micronutrients, and demonstrate the potential of using FF biomass as functional food materials.

Alginate-coated pomelo pith cellulose matrix for probiotic encapsulation and controlled release

A novel carrier comprised of ethanol- and alkali-modified cellulosic pomelo pith matrix coated with alginate was developed to improve viability while enabling gastrointestinal release of probiotics. Scanning electron microscopy imaging revealed the agricultural byproduct had a honeycomb-structured cellulose framework, enabling high loading capacity of the probiotic Lactobacillus plantarum up to 9 log CFU/g. Ethanol treatment opened up pores with an average diameter of 97 μm, while alkali treatment increased swelling and porosity, with an average pore size of 51 μm. The survival rate through the stomach was increased from 89.76 % to 91.08 % and 91.24 % after ethanol and alkali modification, respectively. The control group displayed minimal release in the first 4 h followed by a burst release. Both ethanol modification and alkali modification resulted in constant linear release over time. The release time was prolonged when decreasing the width of the pomelo peel rolls from 10 mm to 5 mm while keeping the volume of the peel constant. After 8 weeks of refrigerated storage, the cellulose-encapsulated probiotics retained viability above 7 log CFU/g. This study demonstrates the potential of the structurally intact, sustainably-sourced cellulosic pomelo pith for probiotic encapsulation and controlled delivery.

B-Group Vitamins as Potential Prebiotic Candidates: Their Effects on the Human Gut Microbiome

In recent years, thousands of studies have demonstrated the importance of the gut microbiome for human health and its relationship with certain diseases. The search for new gut microbiome modulators has thus become an objective to beneficially alter the gut microbiome composition and/or metabolic activity, which may modify intestinal physiology. Growing evidence has shown that B-group vitamins might be considered as potential candidates as gut microbiome modulators. However, the relationship between the B-group vitamins and the gut microbiome remains largely unexplored. Studies have suggested that non-absorbed B-group vitamins administered orally can reach the distal intestine or even the colon where these vitamins may have potential health benefits for the host. Clinical trials supporting this effect are still limited. In this review, we discuss evidence regarding the modulatory effects of B-group vitamins on the gut microbiome with a focus on their potential role as prebiotic candidates.

Polysaccharides and proteins-based bionanocomposites for microencapsulation of probiotics to improve stability and viability in the gastrointestinal tract: A review

Probiotics have recently received significant attention due to their various benefits, such as the modulation of gut flora, reduction of blood sugar and insulin resistance, prevention and treatment of digestive disorders, and strengthening of the immune system. One of the major issues concerning probiotics is the maintenance of their viability in the presence of digestive conditions and extended shelf life during storage. To address this concern, numerous techniques have been explored to achieve success. Among these methods, the microencapsulation of probiotics has been proposed as the most effective way to overcome this challenge. The combination of nanomaterials with biopolymer coating is considered a novel approach to improve its viability and effective delivery. The use of polysaccharides and proteins-based bionanocomposites for microencapsulation of probiotics has emerged as an efficient and promising approach for maintaining cell viability and targeted delivery. This review article aims to investigate the use of different bionanocomposites in microencapsulation of probiotics and their effect on cell survival in long-term storage and harsh conditions in the gastrointestinal tract.

Exploring the role of gut microbiota in advancing personalized medicine

Ongoing extensive research in the field of gut microbiota (GM) has highlighted the crucial role of gut-dwelling microbes in human health. These microbes possess 100 times more genes than the human genome and offer significant biochemical advantages to the host in nutrient and drug absorption, metabolism, and excretion. It is increasingly clear that GM modulates the efficacy and toxicity of drugs, especially those taken orally. In addition, intra-individual variability of GM has been shown to contribute to drug response biases for certain therapeutics. For instance, the efficacy of cyclophosphamide depends on the presence of Enterococcus hirae and Barnesiella intestinihominis in the host intestine. Conversely, the presence of inappropriate or unwanted gut bacteria can inactivate a drug. For example, dehydroxylase of Enterococcus faecalis and Eggerthella lenta A2 can metabolize L-dopa before it converts into the active form (dopamine) and crosses the blood-brain barrier to treat Parkinson's disease patients. Moreover, GM is emerging as a new player in personalized medicine, and various methods are being developed to treat diseases by remodeling patients' GM composition, such as prebiotic and probiotic interventions, microbiota transplants, and the introduction of synthetic GM. This review aims to highlight how the host's GM can improve drug efficacy and discuss how an unwanted bug can cause the inactivation of medicine.

Recent research advances on oral colon-specific delivery system of nature bioactive components: A review

Oral colon-specific delivery system (OCDS) is a targeted approach that aims to directly deliver bioactive compounds directly to the colon following oral administration, thereby enhancing the colonic release of bioactive substances and minimizing adverse reactions. The effectiveness of bioactive substances in the colon hinges on the degree of release, which are affected by various factors including pH, mucosal barrier, delivery time and so on. Therefore, this review provides a comprehensive overview of the key factors affecting oral colon-specific release of bioactive components firstly. Considering the oral safety, this review then mainly focuses on the types of carriers with edible OCDS and preparation strategies for OCDS. Finally, several preparation strategies for loading typical natural bioactive ingredients into oral safe OCDS are reviewed, along with future development prospects.

Colon-targeted delivery of polyphenols: construction principles, targeting mechanisms and evaluation methods

Polyphenols have received considerable attention for their promotive effects on colonic health. However, polyphenols are mostly sensitive to harsh gastrointestinal environments, thus, must be protected. It is necessary to design and develop a colon-targeted delivery system to improve the stability, colon-targeting and bioavailability of polyphenols. This paper mainly introduces research on colon-targeted controlled release of polyphenols. The physiological features affecting the dissolution, release and absorption of polyphenol-loaded delivery systems in the colon are first discussed. Simultaneously, the types of colon-targeted carriers with different release mechanisms are described, and colon-targeting assessment models that have been studied so far and their advantages and limitations are summarized. Based on the current research on polyphenols colon-targeting, outlook and reflections are proposed, with the goal of inspiring strategic development of new colon-targeted therapeutics to ensure that the polyphenols reach the colon with complete bioactivity.

The potential of curcumin-based co-delivery systems for applications in the food industry: Food preservation, freshness monitoring, and functional food

Currently, curcumin-based co-delivery systems are receiving widespread attention. However, a systematic summary of the possibility of curcumin-based co-delivery systems used for the food industry from multiple directions based on the functional characteristics of curcumin is lacking. This review details the different forms of curcumin-based co-delivery systems including the single system of nanoparticle, liposome, double emulsion, and multiple systems composed of different hydrocolloids. The structural composition, stability, encapsulation efficiency, and protective effects of these forms are discussed comprehensively. The functional characteristics of curcumin-based co-delivery systems are summarized, involving biological activity (antimicrobial and antioxidant), pH-responsive discoloration, and bioaccessibility/bioavailability. Correspondingly, potential applications for food preservation, freshness detection, and functional foods are introduced. In the future, more novel co-delivery systems for active ingredients and food matrices should be developed. Besides, the synergistic mechanisms between active ingredients, delivery carrier/active ingredient, and external physical condition/active ingredient should be explored. In conclusion, curcumin-based co-delivery systems have the potential to be widely used in the food industry.

Electrospinning and Electrospraying: Emerging Techniques for Probiotic Stabilization and Application

Probiotics are beneficial for human health. However, they are vulnerable to adverse effects during processing, storage, and passage through the gastrointestinal tract, thus reducing their viability. The exploration of strategies for probiotic stabilization is essential for application and function. Electrospinning and electrospraying, two electrohydrodynamic techniques with simple, mild, and versatile characteristics, have recently attracted increased interest for encapsulating and immobilizing probiotics to improve their survivability under harsh conditions and promoting high-viability delivery in the gastrointestinal tract. This review begins with a more detailed classification of electrospinning and electrospraying, especially dry electrospraying and wet electrospraying. The feasibility of electrospinning and electrospraying in the construction of probiotic carriers, as well as the efficacy of various formulations on the stabilization and colonic delivery of probiotics, are then discussed. Meanwhile, the current application of electrospun and electrosprayed probiotic formulations is introduced. Finally, the existing limitations and future opportunities for electrohydrodynamic techniques in probiotic stabilization are proposed and analyzed. This work comprehensively explains how electrospinning and electrospraying are used to stabilize probiotics, which may aid in their development in probiotic therapy and nutrition.

Microbiota-sensitive drug delivery systems based on natural polysaccharides for colon targeting

Colon targeting is an ongoing challenge, particularly for the oral administration of biological drugs or local treatment of inflammatory bowel disease (IBD). In both cases, drugs are known to be sensitive to the harsh conditions of the upper gastrointestinal tract (GIT) and, thus, must be protected. Here, we provide an overview of recently developed colonic site-specific drug delivery systems based on microbiota sensitivity of natural polysaccharides. Polysaccharides act as a substrate for enzymes secreted by the microbiota located in the distal part of GIT. The dosage form is adapted to the pathophysiology of the patient and, thus, a combination of bacteria-sensitive and time-controlled release or pH-dependent systems can be used for delivery.

Improving the bioaccessibility of lipophilic ingredient in its oral intestinal delivery by ultrasound and biological cross-linker

BACKGROUND

Great efforts have been made to improve the oral bioaccessibility of lipophilic ingredients with multi-functionalities. Achieving intestinal delivery of lipophilic ingredients and their encapsulation in micelles composed of bile salts and lipid hydrolysates (i.e. fatty acids) is critical for improving oral bioaccessibility. Therefore, oil-core microcapsules are considered ideal carriers of lipophilic ingredients. Previous studies have reported oil-core/zein-shell microcapsules constructed by a one-step anti-solvent process. Still, its efficacy as an intestinal delivery system was limited because if the porous shell structure.

RESULTS

Zein solution was pretreated with ultrasound and tannic acid (TA) cross-linking. Composite oil-core microcapsule (COM) with a compact shell structure was successfully prepared by using modified zein solution in the anti-solvent process. Fourier-transform infrared spectroscopy and circular dichroism analyses indicated that ultrasound and TA synergistically promote the conformational transition of zein from α-helix to β-sheet and enhance the hydrophobic interactions among protein chains. The above changes contribute to the strengthen of shell zein network. Correspondingly, COM presents superior encapsulation efficiency and environmental stability over the simple oil-core microcapsule (SOM) prepared without the use of ultrasound and TA. Furthermore, antioxidant activity of β-carotene was well retained during the encapsulation process. In vitro studies indicated that COM was more resistant to digestibility and acid-induced swelling. More than 87% of β-carotene could be released in the intestine in a sustainable way. The controllable release behavior thus promoted a significant increase in bioaccessibility of β-carotene encapsulated in COM compared to SOM (85.9% versus 48.5%).

CONCLUSION

The COM generated here shows potential for bioaccessibility improvement of lipophilic ingredients. © 2022 Society of Chemical Industry.

Effects of different hydrocolloids on the water migration, rheological and 3D printing characteristics of β-carotene loaded yam starch-based hydrogel

The effects of guar gum (GG), xanthan gum (XG), carrageenan gum (CG), xanthan-guar gum blend (XG-GG), chitosan (CS), gum arabic (GA) on the water migration, rheological and 3D printing properties of β-carotene loaded yam starch-based hydrogel (BCH) were investigated to expand product form of β-carotene. The results showed that CS addition promoted the migration of weakly bound water to tightly bound water in BCH. Addition of GG, CG, XG-GG, CS and GA enhanced apparent viscosity, G', G'', hardness and gumminess of BCH. CG, XG-GG, CS and GA addition improved printing stability of BCH. The printed objects added with GG and CS displayed smooth lines with fine resolution and higher formability, which showed a more uniform pore distribution and thinner gel skeleton structure. The results of XRD showed that hydrocolloids addition decreased the relative crystallinity of BCH. A combination of physicochemical parameters could be used to discriminate samples through hierarchical cluster analysis.

Encapsulation of polyphenols in pH-responsive micelles self-assembled from octenyl-succinylated curdlan oligosaccharide and its effect on the gut microbiota

An amphiphilic polymer based on octenyl succinic anhydride-modified curdlan oligosaccharide (MCOS) was synthesized. The critical micelle concentration of MCOS was 3.91 μg·mL-1. MCOS could self-assemble into spherical micelles with a particle size of 230.1 nm and a zeta potential of - 37.9 mV. When used for polyphenol encapsulation, the loading capacity of curcumin and quercetin-co-encapsulated micelles was higher than that of single-polyphenol encapsulated micelles. In vitro gastrointestinal release test showed that the MCOS micelle presented a pH-dependent release, released a little polyphenol in simulated gastric fluid, but presented sustained release in the simulated intestinal fluid. The gastrointestinal-digested polyphenol-loaded micelles exhibited excellent antioxidant ability. In vitro human fecal fermentation indicated that the MCOS carrier could promote the production of short-chain fatty acids by gut microbiota and exhibited the highest relative abundance of Megamonas. In addition, the supplementation of curcumin and quercetin-co-loaded MCOS micelles increased the relative abundance of Bifidobacterium and inhibited the growth of Escherichia_Shigella. These findings indicated that the MCOS carrier can be potentially used for the colon-targeted delivery of hydrophobic polyphenols due to its pH-responsive property.

Updated design strategies for oral delivery systems: maximized bioefficacy of dietary bioactive compounds achieved by inducing proper digestive fate and sensory attributes

Interest in the application of dietary bioactive compounds (DBC) in healthcare and pharmaceutical industries has motivated researchers to develop functional delivery systems (FDS) aiming to maximize their bioefficacy. As the direct and indirect health benefiting effects of DBC are acknowledged, traditional design principle of FDS aiming at improving the bioavailability of intact DBC is challenged by the updated one, where the maximized bioefficacy of DBC delivered by FDS will be achieved via rationally absorbed at target sites with proper metabolism pathways. This article briefly summarized the absorption and metabolic fates of orally digested DBC along with their direct and indirect mechanisms to perform health benefiting effects. Current strategies in designing the next generation FDS with an emphasis on their modulation effects on the distribution portion between the upper and lower digestive tract, portal vein and lymphatic absorption, human digestive and gut microbiota enzymatic mediated metabolism were highlighted. Updated research progresses of FDS in adjusting sensory attributes of food end products and inducing synergistic effects rooting from matrix materials and co-delivered cargos were also discussed. Challenges as well as future perspectives concerning the precise nutrition and the critical role of delivery systems in dietary intervention were proposed.

Novel nano-encapsulated probiotic agents: Encapsulate materials, delivery, and encapsulation systems

Gut microbes are closely associated with most human health. When ingested orally, probiotics can effectively regulate the composition and quantity of human intestinal microorganisms, which is beneficial to human health. However, probiotics will be affected by the harsh environment of the digestive tract during the in vivo transportation process, and ensuring the viability of probiotics is a great challenge. Probiotic encapsulating technology provides an effective solution to this problem. The introduction of extreme temperatures, large probiotic microcapsule sizes and the difficulty in controlling probiotic microcapsule particle sizes mean that traditional microcapsule encapsulation methods have some limitations. From traditional microcapsule technology to the bulk encapsulation of probiotics with nanofibers and nanoparticles to the recent ability to wear nano "armor" for a single probiotic through biofilm, biological membrane and nanocoating. Emerging probiotic nanoagents provides a new conceptual and development direction for the field of probiotic encapsulation. In this review, we presented the characteristics of encapsulated probiotic carrier materials and digestive tract transport systems, we focused on the encapsulation systems of probiotic nanoagents, we analyzed the shortcomings and advantages of the current agent encapsulation systems, and we stated the developmental direction and challenges for these agents for the future.

A pH/Time/Pectinase-Dependent Oral Colon-Targeted System Containing Isoliquiritigenin: Pharmacokinetics and Colon Targeting Evaluation in Mice

BACKGROUND AND OBJECTIVES

Oral colon-targeted gel beads containing isoliquiritigenin (ISL) were successfully designed in our study. In order to further explore the targeting of the colon by the gel beads, a systematic study of their in vivo pharmacokinetics and colon targeting was performed in mice.

METHODS

Eighteen male mice were included in this study. The mice were separated into six groups at random. We collected blood, stomach, duodenum, jejunum, ileum, and colon tissues at 2, 4, 6, 8, 12, and 24 h after oral administration of gel beads containing isoliquiritigenin at a dose of 20 mg/kg. Gel beads in tissues were recorded and taken out to observe their swelling and erosion. The total ISL concentrations in different tissues and gel beads were analyzed by high-performance liquid chromatography.

RESULTS

All gel beads reached the upper part of the stomach at 2 h with no obvious swelling. Most of the gel beads were still in the lower part of stomach, while a small amount had reached the small intestine at 4 h. A few gel beads reached the colon and swelled at 6 h. Furthermore, the gel beads in the colon were swollen and erosive at 8 h. Meanwhile, the plasma ISL concentration could be detected, which indicated that the ISL in the gel beads was absorbed. At 12 h, the gel beads were almost dissolved and the plasma concentration was 8.33 times that at 8 h. At 24 h, the gel beads had completely disappeared, and the plasma concentration was 2.55 times that at 12 h.

CONCLUSION

The gel beads containing ISL are a sustained, controlled, and colon-targeting delivery system that can alter the ISL distribution in the gastrointestinal tract.

Local Delivery of Streptomycin in Microcontainers Facilitates Colonization of Streptomycin-Resistant Escherichia coli in the Rat Colon

Oral antibiotic treatment is often applied in animal studies in order to allow establishment of an introduced antibiotic-resistant bacterium in the gut. Here, we compared the application of streptomycin dosed orally in microcontainers to dosage through drinking water. The selective effect on a resistant bacterial strain, as well as the effects on fecal, luminal, and mucosal microbiota composition, were investigated. Three groups of rats (n = 10 per group) were orally dosed with microcontainers daily for 3 days. One of these groups (STR-M) received streptomycin-loaded microcontainers designed for release in the distal ileum, while the other two groups (controls [CTR] and STR-W) received empty microcontainers. The STR-W group was additionally dosed with streptomycin through the drinking water. A streptomycin-resistant Escherichia coli strain was orally inoculated into all animals. Three days after inoculation, the resistant E. coli was found only in the cecum and colon of animals receiving streptomycin in microcontainers but in all intestinal compartments of animals receiving streptomycin in the drinking water. 16S rRNA amplicon sequencing revealed significant changes in the fecal microbiota of both groups of streptomycin-treated animals. Investigation of the inner colonic mucus layer by confocal laser scanning microscopy and laser capture microdissection revealed no significant effect of streptomycin treatment on the mucus-inhabiting microbiota or on E. coli encroachment into the inner mucus. Streptomycin-loaded microcontainers thus enhanced proliferation of an introduced streptomycin-resistant E. coli in the cecum and colon without affecting the small intestine environment. While improvements of the drug delivery system are needed to facilitate optimal local concentration and release of streptomycin, the application of microcontainers provides new prospects for antibiotic treatment.

IMPORTANCE Delivery of antibiotics in microcontainer devices designed for release at specific sites of the gut represents a novel approach which might reduce the amount of antibiotic needed to obtain a local selective effect. We propose that the application of microcontainers may have the potential to open novel opportunities for antibiotic treatment of humans and animals with fewer side effects on nontarget bacterial populations. In the current study, we therefore elucidated the effects of streptomycin, delivered in microcontainers coated with pH-sensitive lids, on the selective effect on a resistant bacterium, as well as on the surrounding intestinal microbiota in rats.

Bifidobacterium spp. as functional foods: A review of current status, challenges, and strategies

Members of Bifidobacterium are among the first microbes to colonize the human intestine naturally, their abundance and diversity in the colon are closely related to host health. Recently, the gut microbiota has been gradually proven to be crucial mediators of various metabolic processes between the external environment and the host. Therefore, the health-promoting benefits of Bifidobacterium spp. and their applications in food have gradually been widely concerned. The main purpose of this review is to comprehensively introduce general features, colonization methods, and safety of Bifidobacterium spp. in the human gut, highlighting its health benefits and industrial applications. On this basis, the existing limitations and scope for future research are also discussed. Bifidobacteria have beneficial effects on the host's digestive system, immune system, and nervous system. However, the first prerequisite for functioning is to have enough live bacteria before consumption and successfully colonize the colon after ingestion. At present, strain breeding, optimization (e.g., selecting acid and bile resistant strains, adaptive evolution, high cell density culture), and external protection technology (e.g., microencapsulation and protectants) are the main strategies to address these challenges in food application.

Controlled Nutrient Delivery through a pH-Responsive Wood Vehicle

To lower the risk of disease and improve health, many nutrients benefit from intestinal-targeted delivery. Here, we present a nutrient-delivery system based on a pH-responsive "wood scroll", in which nutrients are stored, protected, and controllably released through the rolled structure and natural microchannels of a flexible wood substrate, thus ensuring higher bioactivity as well as prolonged steady release of the nutrient load to the intestine. We loaded the wood's natural microchannels with probiotics as a proof-of-concept demonstration. The probiotic-loaded wood scrolls can survive the simulated conditions of the stomach with a high survival rate (95.40%) and exhibit prolonged release (8 h) of the probiotic load at a constant release rate (4.17 × 10⁸ CFUs/h) in the simulated conditions of the intestine. Moreover, by modifying the macroscopic geometry and microstructures of the wood scrolls, both the nutrient loading and release behaviors can be tuned over a wide range for customized or personalized nutrient management. The wood scrolls can also deliver other types of nutrients, as we demonstrate for tea polyphenols and rapeseed oil. This wood scroll design illustrates a promising structurally controlled strategy for the delivery of enteric nutrients using readily available, low-cost, and biocompatible biomass materials that have a naturally porous structure for nutrient storage, protection, and controlled release.

Colon-targeted drug delivery of polysaccharide-based nanocarriers for synergistic treatment of inflammatory bowel disease: A review

Drugs such as immunosuppressants and glucocorticoids used for the treatment of inflammatory bowel disease (IBD) have certain troubling side effects. Polysaccharide-based nanocarriers with high safety and bioavailability are often used in the construction of colon-targeted drug nanodelivery systems (DNSs). It can help the drug resist the harsh environment of gastrointestinal tract, improve stability and concentrate on the intestinal inflammation regions as much as possible, which effectively reduces drug side effects and enhances its bioavailability. Certain polysaccharides, as prebiotics, can not only endow DNSs with the ability to target the colon based on enzyme responsive properties, but also cooperate with drugs to alleviate IBD due to its good anti-inflammatory activity and intestinal microecological regulation. The changes in the gastrointestinal environment of patients with IBD, the colon-targeted drug delivery process of polysaccharide-based nanocarriers and its synergistic treatment mechanism for IBD were reviewed. Polysaccharides used in polysaccharide-based nanocarriers for IBD were summarized.

Preparation, characterization of PLGA/chitosan nanoparticles as a delivery system for controlled release of DHA

In this work, a novel DHA-loaded nanoparticle with PLGA and chitosan (PCSDNP) was successfully prepared. The structure of PCSDNP and DHA-loaded PLGA nanoparticles was measured by transmission electron microscope, scanning electron microscope, and differential scanning calorimeter. The interaction strength between DHA, PLGA, and chitosan was evaluated through Fourier transform infrared spectroscopy. The curves of controlled DHA release and stabilities for different environmental factors of two NPs were evaluated. Importantly, two NPs were almost regularly spherical and the interactions were hydrogen bonds and electrostatic interactions between PLGA and chitosan. These NPs had a good encapsulation rate (80.45%) and high-water solubility than the free DHA molecule. In simulated gastrointestinal fluid, two NPs showed a controlled-release pattern. Overall, PCSDNP had better stability and controlled-release effect with the synergy between CS and PLGA under the conditions of pH (2- 7), ionic strength (0- 500 mM), storage time (0- 42 d), and temperature (30- 80 °C).

Curcumin encapsulation in nanostructures for cancer therapy: A 10-year overview

Curcumin (CUR) is a phenolic compound present in some herbs, including Curcuma longa Linn. (turmeric rhizome), with a high bioactive capacity and characteristic yellow color. It is mainly used as a spice, although it has been found that CUR has interesting pharmaceutical properties, acting as a natural antioxidant, anti-inflammatory, antimicrobial, and antitumoral agent. Nonetheless, CUR is a hydrophobic compound with low water solubility, poor chemical stability, and fast metabolism, limiting its use as a pharmacological compound. Smart drug delivery systems (DDS) have been used to overcome its low bioavailability and improve its stability. The current work overviews the literature from the past 10 years on the encapsulation of CUR in nanostructured systems, such as micelles, liposomes, niosomes, nanoemulsions, hydrogels, and nanocomplexes, emphasizing its use and ability in cancer therapy. The studies highlighted in this review have shown that these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged CUR release, and reduced side effects, among other interesting advantages.

Oral fate and stabilization technologies of lactoferrin: a systematic review

Lactoferrin (Lf), a bioactive protein initially found in many biological secretions including milk, is regarded as the nutritional supplement or therapeutic ligand due to its multiple functions. Research on its mode of action reveals that intact Lf or its active peptide (i.e., lactoferricin) shows an important multifunctional performance. Oral delivery is considered as the most convenient administration route for this bioactive protein. Unfortunately, Lf is sensitive to the gastrointestinal (GI) physicochemical stresses and lactoferricin is undetectable in GI digesta. This review introduces the functionality of Lf at the molecular level and its degradation behavior in GI tract is discussed in detail. Subsequently, the absorption and transport of Lf from intestine into the blood circulation, which is pivotal to its health promoting effects in various tissues, and some assisting labeling methods are discussed. Stabilization technologies aiming at preserving the structural integrity and functional properties of orally administrated Lf are summarized and compared. Altogether, this work comprehensively reviews the structure-function relationship of Lf, its oral fate and the development of stabilization technologies for the enhancement of the oral bioavailability of Lf. The existing limitations and scope for future research are also discussed.

Microfluidic Assembly: An Innovative Tool for the Encapsulation, Protection, and Controlled Release of Nutraceuticals

Nutraceuticals have been gradually accepted as food ingredients that can offer health benefits and provide protection against several diseases. It is widely accepted due to potential nutritional benefits, safety, and therapeutic effects. Most nutraceuticals are vulnerable to the changes in the external environment, which leads to poor physical and chemical stability and absorption. Several researchers have designed various encapsulation technologies to promote the use of nutraceuticals. Microfluidic technology is an emerging approach which can be used for nutraceutical delivery with precise control. The delivery systems using microfluidic technology have obtained much interest in recent years. In this review article, we have summarized the recently introduced nutraceutical delivery platforms including emulsions, liposomes, microspheres, microgels, and polymer nanoparticles based on microfluidic techniques. Emphasis has been made to discuss the advantages, preparations, characterizations, and applications of nutraceutical delivery systems. Finally, the challenges, several up-scaling methods, and future expectations are discussed.

Microencapsulation of Lactobacillus plantarum in W/O emulsions of okara oil and block-copolymers of poly(acrylic acid) and pluronic using microfluidic devices

Okara oil is a by-product remaining from defatting okara, the solid residue generated after extracting the aqueous fraction of grounded soybeans in the elaboration of soy beverages. The goal of this work was to encapsulate the probiotic Lactobacillus plantarum CIDCA 83114 into W/O emulsions composed of a block-copolymer constituted of pluronic® and acrylic acid (PPP12) and okara oil, prepared in microfluidic devices. For comparative purposes, alginate was also included as a second dispersed phase. Lactobacillus plantarum CIDCA 83114 was suspended in PPP12 or alginate giving rise to dispersed phases with different compositions, named I, II, III and IV. Controls were prepared by suspending microorganisms in water as dispersed phase. 6-carboxyfluorescein was added as bacterial marker in all the emulsions. The presence of green dyed bacteria in the dispersed phases, inside the droplets of the emulsions and the absence of fluorescence outside them, confirmed the complete encapsulation of bacteria in the dispersed phases. After being prepared, emulsions were freeze-dried. The exposure to gastric conditions did not lead to significant differences among the emulsions containing polymers. However, in all cases bacterial counts were significantly lower than those of the control. After exposing emulsions to the simulated intestinal environment, bacterial counts in assays I, II and III (emulsions composed of only one dispersed phase or of two dispersed phases with bacteria resuspended in the PPP12 one) were significantly greater than those of the control (p < 0.05) and no detectable microorganisms were observed for assay IV (emulsions composed of two dispersed phases with bacteria resuspended in the alginate one). In particular, bacterial cultivability in emulsions corresponding to assay I (only PPP12 as dispersed phase) exposed to the intestinal environment was 8.22 ± 0.02 log CFU/mL (2 log CFU higher than the values obtained after gastric digestion). These results support the role of PPP12 as an adequate co-polymer to protect probiotics from the gastric environment, enabling their release in the gut, with great potential for food or nutraceutical applications.

Microwave-initiated rapid synthesis of phthalated cashew gum for drug delivery systems

Chemical modification of polysaccharides is an important approach for their transformation into customized matrices that suit different applications. Microwave irradiation (MW) has been used to catalyze chemical reactions. This study developed a method of MW-initiated synthesis for the production of phthalated cashew gum (Phat-CG). The structural characteristics and physicochemical properties of the modified biopolymers were investigated by FTIR, GPC, ¹H NMR, relaxometry, elemental analysis, thermal analysis, XRD, degree of substitution, and solubility. Phat-CG was used as a matrix for drug delivery systems using benznidazole (BNZ) as a model drug. BNZ is used in the pharmacotherapy of Chagas disease. The nanoparticles were characterized by size, PDI, zeta potential, AFM, and in vitro release. The nanoparticles had a size of 288.8 nm, PDI of 0.27, and zeta potential of -31.8 mV. The results showed that Phat-CG has interesting and promising properties as a new alternative for improving the treatment of Chagas disease.