Chitosan-Alginate Microcapsules Provide Gastric Protection and Intestinal Release of ICAM-1-Targeting Nanocarriers, Enabling GI Targeting In Vivo

Preparation of a Lactobacillus rhamnosus ATCC 7469 microencapsulated-lactulose synbiotic and its effect on equol production

Equol is a highly active product of soy isoflavones produced by specific bacteria in the human or animal colon. However, equol production is influenced by differences in the gut flora carried by the body. Our previous research has shown that a synbiotic preparation comprising the probiotic Lactobacillus rhamnosus ATCC 7469 and the prebiotic lactulose can enhance equol production by modulating the intestinal flora. Nevertheless, the harsh environment of the gastrointestinal tract limits this capability by diminishing the number of probiotics reaching the colon. Microencapsulation of probiotics is an effective strategy to enhance their viability. In this study, probiotic gel microspheres (SA-S-CS) were prepared using an extrusion method, with sodium alginate (SA) and chitosan (CS) serving as the encapsulating materials. Scanning electron microscopy (SEM) was employed to observe the surface morphology and the internal distribution of bacteria within the microcapsules. The structural characteristics of the microcapsules were investigated using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Furthermore, the thermal stability, storage stability, probiotic viability post-simulated gastrointestinal fluid treatment, and colon release rate were examined. Finally, the impact of probiotic microencapsulation on promoting equol production by the synbiotic preparation was assessed. The results indicated that the microcapsules exhibited a spherical structure with bacteria evenly distributed on the inner surface. Studies on thermal and storage stability showed that the number of viable cells in the probiotic microcapsule group significantly increased compared to the free probiotic group. Gastrointestinal tolerance studies revealed that after in vitro simulated gastrointestinal digestion, the amount of viable cells in the microcapsules was 7 log10 CFU g-1, demonstrating good gastrointestinal tolerance. Moreover, after incubation in simulated colonic fluid for 150 min, the release rate of probiotics reached 93.13%. This suggests that chitosan-coated sodium alginate microcapsules can shield Lactobacillus rhamnosus ATCC 7469 from the gastrointestinal environment, offering a novel model for synbiotic preparation to enhance equol production.

Pectin-Chitosan Hydrogel Beads for Delivery of Functional Food Ingredients

A common challenge in hydrogel-based delivery systems is the premature release of low molecular weight encapsulates through diffusion or swelling and reduced cell viability caused by the low pH in gastric conditions. A second biopolymer, such as chitosan, can be incorporated to overcome this. Chitosan is usually associated with colonic drug delivery systems. We intended to formulate chitosan-coated pectin beads for use in delaying premature release of the encapsulate under gastric conditions but allowing release through disintegration under intestinal conditions. The latter is of utmost importance in delivering most functional food ingredients. Therefore, this study investigated the impact of formulation and process conditions on the size, sphericity, and dissolution behavior of chitosan-coated hydrogel beads prepared by interfacial coacervation. The size and sphericity of the beads depend on the formulation and range from approximately 3 to 5 mm and 0.82 to 0.95, respectively. Process conditions during electro-dripping may be modulated to tailor bead size. Depending on the voltage, bead size ranged from 1.5 to 4 mm. Confocal laser scanning microscopy and scanning electron microscopy confirmed chitosan shell formation around the pectin bead. Chitosan-coated beads maintained their size and shape in simulated gastric fluid but experienced structural damage in simulated intestinal fluid. Therefore, they represent a novel delivery system for functional food ingredients.

Pharmacological effects of Astragalus polysaccharides in treating neurodegenerative diseases

Astragalus membranaceus widely used in traditional Chinese medicine, exhibits multiple pharmacological effects, including immune stimulation, antioxidation, hepatoprotection, diuresis, antidiabetes, anticancer, and expectorant properties. Its main bioactive compounds include flavonoids, triterpene saponins, and polysaccharides. Astragalus polysaccharides (APS), one of its primary bioactive components, have been shown to possess a variety of pharmacological activities, such as antioxidant, immunomodulatory, anti-inflammatory, antitumor, antidiabetic, antiviral, hepatoprotective, anti-atherosclerotic, hematopoietic, and neuroprotective effects. This review provides a comprehensive summary of the molecular mechanisms and therapeutic effects of APS in treating neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). It discusses how APS improve insulin resistance, reduce blood glucose levels, enhance cognitive function, and reduce Aβ accumulation and neuronal apoptosis by modulating various pathways such as Nrf2, JAK/STAT, Toll, and IMD. For PD, APS protect neurons and stabilize mitochondrial function by inhibiting ROS production and promoting autophagy through the PI3K/AKT/mTOR pathway. APS also reduce oxidative stress and neurotoxicity induced by 6-hydroxydopamine, showcasing their neuroprotective effects. In MS, APS alleviate symptoms by suppressing T cell proliferation and reducing pro-inflammatory cytokine expression via the PD-1/PD-Ls pathway. APS promote myelin regeneration by activating the Sonic hedgehog signaling pathway and fostering the differentiation of neural stem cells into oligodendrocytes. This article emphasizes the significant antioxidant, anti-inflammatory, immunomodulatory, and neuroprotective pharmacological activities of APS, highlighting their potential as promising candidates for the treatment of neurodegenerative diseases.

Nanoparticle-Empowered Core-Shell Microcapsules: From Architecture Design to Fabrication and Functions

Compartmentalization is a powerful concept to integrate multiscale components with diverse functionalities into miniature architectures. Inspired by evolution-optimized cell compartments, synthetic core-shell capsules enable storage of actives and on-demand delivery of programmed functions, driving scientific progress across various fields including adaptive materials, sustainable electronics, soft robotics, and precision medicine. To simultaneously maximize structural stability and environmental sensitivity, which are the two most critical characteristics dictating performance, diverse nanoparticles are incorporated into microcapsules with a dense shell and a liquid core. Recent studies have revealed that these nano-additives not only enhance the intrinsic properties of capsules including mechanical robustness, optical behaviors, and thermal conductivity, but also empower dynamic features such as triggered release, deformable structures, and fueled mobility. In this review, the physicochemical principles that govern nanoparticle assembly during microencapsulation are examined in detail and the architecture-controlled functionalities are outlined. Through the analysis of how each primary method implants nanoparticles into microcapsules, their distinct spatial organizations within the core-shell structures are highlighted. Following a detailed discussion of the specialized functions enabled by specific nanoparticles, the vision of the required fundamental insights and experimental studies for this class of microcarriers to fulfill its potential are sketched.

Microgels for Cell Delivery in Tissue Engineering and Regenerative Medicine

Microgels prepared from natural or synthetic hydrogel materials have aroused extensive attention as multifunctional cells or drug carriers, that are promising for tissue engineering and regenerative medicine. Microgels can also be aggregated into microporous scaffolds, promoting cell infiltration and proliferation for tissue repair. This review gives an overview of recent developments in the fabrication techniques and applications of microgels. A series of conventional and novel strategies including emulsification, microfluidic, lithography, electrospray, centrifugation, gas-shearing, three-dimensional bioprinting, etc. are discussed in depth. The characteristics and applications of microgels and microgel-based scaffolds for cell culture and delivery are elaborated with an emphasis on the advantages of these carriers in cell therapy. Additionally, we expound on the ongoing and foreseeable applications and current limitations of microgels and their aggregate in the field of biomedical engineering. Through stimulating innovative ideas, the present review paves new avenues for expanding the application of microgels in cell delivery techniques.

Acer tegmentosum extract-mediated silver nanoparticles loaded chitosan/alginic acid scaffolds enhance healing of E. coli-infected wounds

This work developed Acer tegmentosum extract-mediated silver nanoparticles (AgNPs) loaded chitosan (CS)/alginic acid (AL) scaffolds (CS/AL-AgNPs) to enhance the healing of E. coli-infected wounds. The SEM-EDS and XRD results revealed the successful formation of the CS/AL-AgNPs. FTIR analysis evidenced that the anionic group of AL (-COO-) and cationic amine groups of CS (-NH3+) were ionically crosslinked to form scaffold (CS/AL). The CS/AL-AgNPs exhibited significant antimicrobial activity against both Gram-positive (G+) and Gram-negative (G-) bacterial pathogens, while being non-toxic to red blood cells (RBCs), the hen's egg chorioallantoic membrane (HET-CAM), and a non-cancerous cell line (NIH3T3). Treatment with CS/AL-AgNPs significantly accelerated the healing of E. coli-infected wounds by regulating the collagen deposition and blood parameters as evidenced by in vivo experiments. Overall, these findings suggest that CS/AL-AgNPs are promising for the treatment of infected wounds.

pH Sensitive Quercetin Nanoparticles Ameliorate DSS-Induced Colitis in Mice by Colon-Specific Delivery

SCOPE

Ulcerative colitis (UC) is a classic inflammatory bowel disease (IBD) that represents a serious threat to human health. As a natural flavonoid with multiple biological activities, quercetin (QCT) suffers from low bioavailability through limitations in chemical stability. Here, the study investigates the regulatory effects of quercetin nanoparticles (QCT NPs) on dextran sulfate sodium (DSS) induced colitis mice.

METHODS AND RESULTS

Chitosan is modified to obtain N-succinyl chitosan (NSC) with superior water solubility. Nanoparticles composed of sodium alginate (SA) and NSC can encapsulate QCT after cross-linking, forming QCT NPs. In vitro drug release assays demonstrate the pH sensitivity of QCT NPs. Compared with free quercetin, QCT NPs have better therapeutic efficacy in modulating gut microbiota and its metabolites short chain fatty acid (SCFAs) to relieve DSS-induced colitis in mice, thereby alleviating colon inflammatory infiltration, increasing goblet cells density and mucus protein, ameliorating TNF-α, IL-1β, IL-6, IL-10, and Myeloperoxidase (MPO) levels, and recovering intestinal barrier integrity.

CONCLUSION

pH sensitive QCT nanoparticles can reduce inflammatory reaction, improve gut microbiota, and repair intestinal barrier by targeting colon, thus improving DSS induced colitis in mice, providing reference for the treatment of colitis.

Classification and design strategies of polysaccharide-based nano-nutrient delivery systems for enhanced bioactivity and targeted delivery: A review

Since many nutrients are highly sensitive, they cannot be absorbed and utilized efficiently by the body. Using nano-delivery systems to encapsulate nutrients is an effective method of solving the problems associated with the application of nutrients at this stage. Polysaccharides, as natural biomaterials, have a unique chemical structure, ideal biocompatibility, biodegradability and low immunogenicity. This makes polysaccharides powerful carriers that can enhance the biological activity of nutrients. However, the true role of polysaccharide-based delivery systems requires an in-depth understanding of the structural and physicochemical characteristics of polysaccharide-based nanodelivery systems, as well as effective modulation of the intestinal delivery mechanism and the latest advances in nano-encapsulation. This review provides an overview of polysaccharide-based nano-delivery systems dependent on different carrier types, emphasizing recent advances in the application of polysaccharides, a biocomposite material designed for nutrient delivery systems. Strategies for polysaccharide-based nano-delivery systems to enhance the bioavailability of orally administered nutrients from the perspective of the intestinal absorption barrier are presented. Characterization methods for polysaccharide-based nano-delivery systems are presented as well as an explanation of the formation mechanisms behind nano-delivery systems from the perspective of molecular forces. Finally, we discussed the challenges currently facing polysaccharide-based nano-delivery systems as well as possible future directions for the future.

Injectable hydrogel particles for amorphous solid formulation of biologics

The fast pace of breakthroughs in cancer immunotherapy, combined with the new paradigm of moving toward high-concentration dosages and combinatorial treatments, is generating new challenges in the formulation of biologics. To address these challenges, we describe a method of formulation that enables high-concentration injectable and stable formulation of biologics as amorphous solids in aqueous suspension. This technology combines the benefits of liquid formulation with the stability of solid formulation and eliminates the need for drying and reconstitution. This widely applicable formulation integrates the amorphous solid forms of antibodies with the injectability, lubricity, and tunability of soft alginate hydrogel particles using a minimal process. The platform was evaluated for anti-PD-1 antibody pembrolizumab and human immunoglobulin G at concentrations up to 300 mg/mL with confirmed quality after release. The soft nature of the hydrogel matrix allowed packing the particles to high volume fractions.

Crystalline Antibody-Laden Alginate Particles: A Platform for Enabling High Concentration Subcutaneous Delivery of Antibodies

Subcutaneous (SC) administration is a desired route for monoclonal antibodies (mAbs). However, formulating mAbs for small injection volumes at high concentrations with suitable stability and injectability is a significant challenge. Here, this work presents a platform technology that combines the stability of crystalline antibodies with injectability and tunability of soft hydrogel particles. Composite alginate hydrogel particles are generated via a gentle centrifugal encapsulation process which avoids use of chemical reactions or an external organic phase. Crystalline suspension of anti-programmed cell death protein 1 (PD-1) antibody (pembrolizumab) is utilized as a model therapeutic antibody. Crystalline forms of the mAb encapsuled in the hydrogel particles lead to stable, high concentration, and injectable formulations. Formulation concentrations as high as 315 mg mL-1 antibody are achieved with encapsulation efficiencies in the range of 89-97%, with no perceivable increase in the number of antibody aggregates. Bioanalytical studies confirm superior maintained quality of the antibody in comparison with formulation approaches involving organic phases and chemical reactions. This work illustrates tuning the alginate particles' disintegration by using partially oxide alginates. Crystalline mAb-laden particles are evaluated for their biocompatibility using cell-based in vitro assays. Furthermore, the pharmacokinetics (PK) of the subcutaneously delivered human anti-PD-1 mAb in crystalline antibody-laden alginate hydrogel particles in Wistar rats is evaluated.

Polymer-based drug delivery systems under investigation for enzyme replacement and other therapies of lysosomal storage disorders

Lysosomes play a central role in cellular homeostasis and alterations in this compartment associate with many diseases. The most studied example is that of lysosomal storage disorders (LSDs), a group of 60 + maladies due to genetic mutations affecting lysosomal components, mostly enzymes. This leads to aberrant intracellular storage of macromolecules, altering normal cell function and causing multiorgan syndromes, often fatal within the first years of life. Several treatment modalities are available for a dozen LSDs, mostly consisting of enzyme replacement therapy (ERT) strategies. Yet, poor biodistribution to main targets such as the central nervous system, musculoskeletal tissue, and others, as well as generation of blocking antibodies and adverse effects hinder effective LSD treatment. Drug delivery systems are being studied to surmount these obstacles, including polymeric constructs and nanoparticles that constitute the focus of this article. We provide an overview of the formulations being tested, the diseases they aim to treat, and the results observed from respective in vitro and in vivo studies. We also discuss the advantages and disadvantages of these strategies, the remaining gaps of knowledge regarding their performance, and important items to consider for their clinical translation. Overall, polymeric nanoconstructs hold considerable promise to advance treatment for LSDs.

Palmitic acid- and cysteine-functionalized nanoparticles overcome mucus and epithelial barrier for oral delivery of drug

Nanoparticles (NPs) used for oral administration have greatly improved drug bioavailability and therapeutic efficacy. Nevertheless, NPs are limited by biological barriers, such as gastrointestinal degradation, mucus barrier, and epithelial barrier. To solve these problems, we developed the PA-N-2-HACC-Cys NPs loaded with anti-inflammatory hydrophobic drug curcumin (CUR) (CUR@PA-N-2-HACC-Cys NPs) by self-assembled amphiphilic polymer, composed of the N-2-Hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC), hydrophobic palmitic acid (PA), and cysteine (Cys). After oral administration, the CUR@PA-N-2-HACC-Cys NPs had good stability and sustained release under gastrointestinal conditions, followed by adhering to the intestine to achieve drug mucosal delivery. Additionally, the NPs could penetrate mucus and epithelial barriers to promote cellular uptake. The CUR@PA-N-2-HACC-Cys NPs could open tight junctions between cells for transepithelial transport while striking a balance between mucus interaction and diffusion through mucus. Notably, the CUR@PA-N-2-HACC-Cys NPs improved the oral bioavailability of CUR, which remarkably relieved colitis symptoms and promoted mucosal epithelial repair. Our findings proved that the CUR@PA-N-2-HACC-Cys NPs had excellent biocompatibility, could overcome mucus and epithelial barriers, and had significant application prospects for oral delivery of the hydrophobic drugs.

Core-Shell Particles: From Fabrication Methods to Diverse Manipulation Techniques

Core-shell particles are micro- or nanoparticles with solid, liquid, or gas cores encapsulated by protective solid shells. The unique composition of core and shell materials imparts smart properties on the particles. Core-shell particles are gaining increasing attention as tuneable and versatile carriers for pharmaceutical and biomedical applications including targeted drug delivery, controlled drug release, and biosensing. This review provides an overview of fabrication methods for core-shell particles followed by a brief discussion of their application and a detailed analysis of their manipulation including assembly, sorting, and triggered release. We compile current methodologies employed for manipulation of core-shell particles and demonstrate how existing methods of assembly and sorting micro/nanospheres can be adopted or modified for core-shell particles. Various triggered release approaches for diagnostics and drug delivery are also discussed in detail.

Mucoadhesive carriers for oral drug delivery

Among the various dosage forms, oral medicine has extensive benefits including ease of administration and patients' compliance, over injectable, suppositories, ocular and nasal. Despite of extensive demand and emerging advantages, over 50% of therapeutic molecules are not available in oral form due to their physicochemical properties. More importantly, most of the biologics, proteins, peptide, and large molecular drugs are mostly available in injectable form. Conventional oral drug delivery system has limitation such as degradation and lack of stability within stomach due to presence of highly acidic gastric fluid, hinders their therapeutic efficacy and demand more frequent and higher dosing. Hence, formulation for controlled, sustained, and targeted drug delivery, need to be designed with feasibility to target the specific region of gastrointestinal (GI) tract such as stomach, small intestine, intestine lymphatic, and colon is challenging. Among various oral delivery approaches, mucoadhesive vehicles are promising and has potential for improving oral drug retention and controlled absorption to treat local diseases within the GI tract, as well systemic diseases. This review provides the overview about the challenges and opportunities to design mucoadhesive formulation for oral delivery of therapeutics in a way to target the specific region of the GI tract. Finally, we have concluded with future perspective and potential of mucoadhesive formulations for oral local and systemic delivery.

Biopolymeric Prodrug Systems as Potential Antineoplastic Therapy

Nowadays, cancer represents a major public health issue, a substantial economic issue, and a burden for society. Limited by numerous disadvantages, conventional chemotherapy is being replaced by new strategies targeting tumor cells. In this context, therapies based on biopolymer prodrug systems represent a promising alternative for improving the pharmacokinetic and pharmacologic properties of drugs and reducing their toxicity. The polymer-directed enzyme prodrug therapy is based on tumor cell targeting and release of the drug using polymer–drug and polymer–enzyme conjugates. In addition, current trends are oriented towards natural sources. They are biocompatible, biodegradable, and represent a valuable and renewable source. Therefore, numerous antitumor molecules have been conjugated with natural polymers. The present manuscript highlights the latest research focused on polymer–drug conjugates containing natural polymers such as chitosan, hyaluronic acid, dextran, pullulan, silk fibroin, heparin, and polysaccharides from Auricularia auricula.

Transformable Gallium-Based Liquid Metal Nanoparticles for Tumor Radiotherapy Sensitization

The past decades have witnessed an increasing interest in the exploration of room temperature gallium-based liquid metal (LM) in the field of microfluidics, soft robotics, electrobiology, and biomedicine. Herein, this study for the first time reports the utilization of nanosized gallium-indium eutectic alloys (EGaIn) as a radiosensitizer for enhancing tumor radiotherapy. The sodium alginate (Alg) functionalized EGaIn nanoparticles (denoted as EGaIn@Alg NPs) are prepared via a simple one-step synthesis method. The coating of Alg not only prevents the aggregation and oxidation of EGaIn NPs in an aqueous solution but also enables them low cytotoxicity, good biocompatibility, and in-situ formation of gels in the Ca²⁺ enriched tumor physiological microenvironment. Due to the metallic nature and high density, EGaIn can increase the generation of reactive oxygen species under the irradiation of X-ray, which can not only directly promote DNA damage and cell apoptosis, but also show an efficient tumor inhibition rate in vivo. Moreover, EGaIn@Alg NPs hold good performance as computed tomography (CT) and photoacoustic tomography (PAT) imaging contrast agents. This work provides an alternative nanotechnology strategy for tumor radiosensitization and also enlarges the biomedical application of gallium-based LM.

Comparison between Nanoparticle Encapsulation and Surface Loading for Lysosomal Enzyme Replacement Therapy

Poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) enhance the delivery of therapeutic enzymes for replacement therapy of lysosomal storage disorders. Previous studies examined NPs encapsulating or coated with enzymes, but these formulations have never been compared. We examined this using hyaluronidase (HAse), deficient in mucopolysaccharidosis IX, and acid sphingomyelinase (ASM), deficient in types A−B Niemann−Pick disease. Initial screening of size, PDI, ζ potential, and loading resulted in the selection of the Lactel II co-polymer vs. Lactel I or Resomer, and Pluronic F68 surfactant vs. PVA or DMAB. Enzyme input and addition of carrier protein were evaluated, rendering NPs having, e.g., 181 nm diameter, 0.15 PDI, −36 mV ζ potential, and 538 HAse molecules encapsulated per NP. Similar NPs were coated with enzyme, which reduced loading (e.g., 292 HAse molecules/NP). NPs were coated with targeting antibodies (> 122 molecules/NP), lyophilized for storage without alterations, and acceptably stable at physiological conditions. NPs were internalized, trafficked to lysosomes, released active enzyme at lysosomal conditions, and targeted both peripheral organs and the brain after i.v. administration in mice. While both formulations enhanced enzyme delivery compared to free enzyme, encapsulating NPs surpassed coated counterparts (18.4- vs. 4.3-fold enhancement in cells and 6.2- vs. 3-fold enhancement in brains), providing guidance for future applications.

Core-shell microparticles: From rational engineering to diverse applications

Core-shell microparticles, composed of solid, liquid, or gas bubbles surrounded by a protective shell, are gaining considerable attention as intelligent and versatile carriers that show great potential in biomedical fields. In this review, an overview is given of recent developments in design and applications of biodegradable core-shell systems. Several emerging methodologies including self-assembly, gas-shearing, and coaxial electrospray are discussed and microfluidics technology is emphasized in detail. Furthermore, the characteristics of core-shell microparticles in artificial cells, drug release and cell culture applications are discussed and the superiority of these advanced multi-core microparticles for the generation of artificial cells is highlighted. Finally, the respective developing orientations and limitations inherent to these systems are addressed. It is hoped that this review can inspire researchers to propel the development of this field with new ideas.

Micro-ecology restoration of colonic inflammation by in-Situ oral delivery of antibody-laden hydrogel microcapsules

In-situ oral delivery of therapeutic antibodies, like monoclonal antibody, for chronic inflammation treatment is the most convenient approach compared with other administration routes. Moreover, the abundant links between the gut microbiota and colonic inflammation indicate that the synergistic or antagonistic effect of gut microbiota to colonic inflammation. However, the antibody activity would be significantly affected while transferring through the gastrointestinal tract due to hostile conditions. Moreover, these antibodies have short serum half-lives, thus, require to be frequently administered with high doses to be effective, leading to low patient tolerance. Here, we develop a strategy utilizing thin shell hydrogel microcapsule fabricated by microfluidic technique as the oral delivering carrier. By encapsulating antibodies in these microcapsules, antibodies survive in the hostile gastrointestinal environment and rapidly release into the small intestine through oral administration route, achieving the same therapeutic effect as the intravenous injection evaluated by a colonic inflammation disease model. Moreover, the abundance of some intestinal microorganisms as the indication of the improvement of inflammation has remarkably altered after in-situ antibody-laden microcapsules delivery, implying the restoration of micro-ecology of the intestine. These findings prove our microcapsules are exploited as an efficient oral delivery agent for antibodies with programmable function in clinical application.

1.

This thin shell hydrogel microcapsules using a water-in-water-in-oil as the template by microfluidic technique for orally delivery of antibodies is generated to protect from hostile stomach microenvironment and rapid released in the small intestine without losing their activity.

2.

The shell contains a double crosslinked network attributed to its ionic crosslinking and covalent crosslinking functionalities.

3.

The antibody-laden microcapsules demonstrate great therapeutic efficacy in DSS-induced colonic inflammation disease models, which is approximated to that of the intravenous injection treatment.

4.

Orally taken antibody-laden microcapsules restore the intestinal micro-ecological dysbiosis.

Enhanced Mucosal Transport of Polysaccharide-Calcium Phosphate Nanocomposites for Oral Vaccination

Oral vaccine has attracted much interest, as it can stimulate both mucosal and systemic immunity with noninvasive and good patient compliance. However, the oral vaccine efficiency is strongly constrained by the low absorption of antigens in the small intestine due to the mucosal barriers. Physicochemical characteristics of nanoparticles (NPs) have strong effects on antigen mucosal penetration, helping to improve immune response. However, surface functions of NPs on mucosal transportation have not been clearly understood. In this work, we elaborately investigated how the surface characteristics of mucoadhesive chitosan and its derivant act on oral antigen absorption and immune response. Core-shell chitosan- and o-carboxymethyl chitosan-coated calcium phosphate (CaP) nanocomposites have been fabricated to investigate the surface property effect on protein antigen delivery using the oral route. The interaction between polymer-coated CaP NPs and the intestinal mucosal layer was studied using mucin absorption, NP diffusion through the mucus layer, NP permeability across the epithelium monolayer, and their cellular uptake by antigen presenting cells in detail. Ex vivo mucosa distribution and in vivo oral immunization of polymer-coated CaP nanocomposites were further examined to demonstrate that the surface property of NPs affects CaP diffusion and penetration through the mucosal layer. As expected, OVA orally delivered by polymer-coated CaP nanocomposites improved the response of mucosal immunity compared to antigen OVA itself in vivo.

Advanced biomaterials in cell preservation: Hypothermic preservation and cryopreservation

Cell-based medicine has made great advances in clinical diagnosis and therapy for various refractory diseases, inducing a growing demand for cell preservation as support technology. However, the bottleneck problems in cell preservation include low efficiency and poor biocompatibility of traditional protectants. In this review, cell preservation technologies are categorized according to storage conditions: hypothermic preservation at 1 °C~35 °C to maintain short-term cell viability that is useful in cell diagnosis and transport, while cryopreservation at -196 °C~-80 °C to maintain long-term cell viability that provides opportunities for therapeutic cell product storage. Firstly, the background and developmental history of the protectants used in the two preservation technologies are briefly introduced. Secondly, the progress in different cellular protection mechanisms for advanced biomaterials are discussed in two preservation technologies. In hypothermic preservation, the hypothermia-induced and extracellular matrix-loss injuries to cells are comprehensively summarized, as well as the recent biomaterials dependent on regulation of cellular ATP level, stabilization of cellular membrane, balance of antioxidant defense system, and supply of mimetic ECM to prolong cell longevity are provided. In cryopreservation, cellular injuries and advanced biomaterials that can protect cells from osmotic or ice injury, and alleviate oxidative stress to allow cell survival are concluded. Last, an insight into the perspectives and challenges of this technology is provided. We envision advanced biocompatible materials for highly efficient cell preservation as critical in future developments and trends to support cell-based medicine. STATEMENT OF SIGNIFICANCE: Cell preservation technologies present a critical role in cell-based applications, and more efficient biocompatible protectants are highly required. This review categorizes cell preservation technologies into hypothermic preservation and cryopreservation according to their storage conditions, and comprehensively reviews the recently advanced biomaterials related. The background, development, and cellular protective mechanisms of these two preservation technologies are respectively introduced and summarized. Moreover, the differences, connections, individual demands of these two technologies are also provided and discussed.

Lollipop-Inspired Multilayered Drug Delivery Hydrogel for Dual Effective, Long-Term, and NIR-Defined Glaucoma Treatment

Glaucoma is an ophthalmic disease that is characterized by elevated intraocular pressure (IOP). Eye drops are the preferred choice to reduce IOP for the treatment of glaucoma. However, the bioavailability of eye drops is low (<5%). Their long-term frequent administration cannot ensure patient compliance, which is the main reason for treatment failure. Inspired by lollipop, herein, a multilayered sodium alginate-chitosan (SA-CS) hydrogel ball (HB) decorated by zinc oxide-modified biochar (ZnO-BC) is developed as a new drug delivery system. The multilayer structure encapsulate timolol maleate (TM) and levofloxacin inside the different layers to realize the sustained release of drugs, which can control ocular hypertension and prevent infection effectively. The results show that the release of TM can be sustained in vitro for longer than 2 weeks. Moreover, IOP is also effectively reduced in vivo. Meanwhile, the photothermal conversion activity of ZnO-BC can regulate drug release on demand after stimulation by near-infrared irradiation. More importantly, the designed HB also shows good biocompatibility and antibacterial properties in vitro and in vivo. In summary, ZnO-BC-SA-CS HB can effectively reduce IOP and is expected to replace the classical tedious eye drop strategy, having potential utilization value in the treatment of glaucoma.

Brij-functionalized chitosan nanocarrier system enhances the intestinal permeability of P-glycoprotein substrate-like drugs

The highly expressed P-glycoprotein (Pgp) in the intestine plays a key role in preventing drugs across the intestinal epithelium, which linked by tight junctions (TJs). Thus increasing the oral bioavailability of Pgp substrate-like drugs (PSLDs) remains a great challenge. Herein, we construct a nanocarrier system derived from Brij-grafted-chitosan (BC) to enhance the oral bioavailability and therapeutic effect of berberine (BBR, a typical PLSD) against diabetic kidney disease. The developed BC nanoparticles (BC-NPs) are demonstrated to improve the intestinal permeability of BBR via transiently and reversibly modulating the intercellular TJs (paracellular pathway) and Pgp-mediated drug efflux (transcellular pathway). As compared to free BBR and chitosan nanoparticles, the BC-NPs enhanced the relative oral bioavailability of BBR in rats (4.4- and 2.7-fold, respectively), and the therapeutic potency of BBR in renal function and histopathology. In summary, such strategy may provide an effective nanocarrier system for oral delivery of BBR and PSLDs.

Design and Optimization of a Self-Assembling Complex Based on Microencapsulated Calcium Alginate and Glutathione (CAG) Using Response Surface Methodology

The aim of this work was to characterize and optimize the formation of molecular complexes produced by the association of calcium alginate and reduced glutathione (GSH). The influence of varying concentrations of calcium and GSH on the production of microcapsules was analyzed using response surface methodology (RSM). The microcapsules were characterized by thermogravimetric analysis (TGA-DTG) and infrared spectroscopy (FTIR) in order to assess the hydration of the complexes, their thermal stability, and the presence of GSH within the complexes. The optimum conditions proposed by RSM to reach the maximum concentration of GSH within complexes were a 15% w/v of GSH and 1.25% w/v of CaCl₂, with which a theorical concentration of 0.043 mg GSH per mg of CAG complex was reached.

Light-Responsive Micelles Loaded With Doxorubicin for Osteosarcoma Suppression

The enhancement of tumor targeting and cellular uptake of drugs are significant factors in maximizing anticancer therapy and minimizing the side effects of chemotherapeutic drugs. A key challenge remains to explore stimulus-responsive polymeric nanoparticles to achieve efficient drug delivery. In this study, doxorubicin conjugated polymer (Poly-Dox) with light-responsiveness was synthesized, which can self-assemble to form polymeric micelles (Poly-Dox-M) in water. As an inert structure, the polyethylene glycol (PEG) can shield the adsorption of protein and avoid becoming a protein crown in the blood circulation, improving the tumor targeting of drugs and reducing the cardiotoxicity of doxorubicin (Dox). Besides, after ultraviolet irradiation, the amide bond connecting Dox with PEG can be broken, which induced the responsive detachment of PEG and enhanced cellular uptake of Dox. Notably, the results of immunohistochemistry in vivo showed that Poly-Dox-M had no significant damage to normal organs. Meanwhile, they showed efficient tumor-suppressive effects. This nano-delivery system with the light-responsive feature might hold great promises for the targeted therapy for osteosarcoma.

The bonding nature of the chemical interaction between trypsin and chitosan based carriers in immobilization process depend on entrapped method: A review

The review article is dedicated to a comprehensive study of the chemical bond formed during the immobilization of the proteolytic enzyme pancreatic trypsin in chitosan-based polymer matrixes and its derivatives. The main focus of the study is to describe the chemical bond that causes immobilization between chitosan based carriers and trypsin. Because the nature of the chemical bond between the carrier and trypsin is a key factor in determining the area of application of the conjugate. It has been found out that after the chemical nature of functional groups, their degree of ionization, the structure of the chemical cross-linking, the medium pH and ionic strength of chitosan are modified, the mechanism of trypsin immobilization is affected. As a result, the attraction enzyme to the matrix occurs due to polar covalent and hydrogen bonds, as well as electrostatic, hydrophobic, Van der Waals forces. The collected research works on the immobilization of trypsin on chitosan-based carriers have been systematized in the paper and shown schematically in subsystems according to the type of chemical interaction. It has been shown that the immobilization of trypsin on chitosan based matrixes occur more often due to the covalent and hydrogen bonds between the protein and the carrier.

Proteomics-Informed Identification of Luminal Targets For In Situ Diagnosis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic condition resulting in impaired intestinal homeostasis. Current practices for diagnosis of IBD are challenged by invasive, demanding procedures. We hypothesized that proteomics analysis could provide a powerful tool for identifying clinical biomarkers for non-invasive IBD diagnosis. Here, the global intestinal proteomes from commonly used in vitro and in vivo models of IBD were analyzed to identify apical and luminal proteins that can be targeted by orally delivered diagnostic agents. Global proteomics analysis revealed upregulated plasma membrane proteins in intestinal segments of proximal- and distal colon from dextran sulfate sodium-treated mice and also in inflamed human intestinal Caco-2 cells pretreated with pro-inflammatory agents. The upregulated colon proteins in mice were compared to the proteome of the healthy ileum, to ensure targeting of diagnostic agents to the inflamed colon. Promising target proteins for future investigations of non-invasive diagnosis of IBD were found in both systems and included Tgm2/TGM2, Icam1/ICAM1, Ceacam1/CEACAM1, and Anxa1/ANXA1. Ultimately, these findings will guide the selection of appropriate antibodies for surface functionalization of imaging agents aimed to target inflammatory biomarkers in situ.

Upconversion optogenetic micro-nanosystem optically controls the secretion of light-responsive bacteria for systemic immunity regulation

Chemical molecules specifically secreted into the blood and targeted tissues by intestinal microbiota can effectively affect the associated functions of the intestine especially immunity, representing a new strategy for immune-related diseases. However, proper ways of regulating the secretion metabolism of specific strains still remain to be established. In this article, an upconversion optogenetic micro-nanosystem was constructed to effectively regulate the specific secretion of engineered bacteria. The system included two major modules: (i) Modification of secretory light-responsive engineered bacteria. (ii) Optical sensing mediated by upconversion optogenetic micro-nanosystem. This system could regulate the efficient secretion of immune factors by engineered bacteria through optical manipulation. Inflammatory bowel disease and subcutaneously transplanted tumors were selected to verify the effectiveness of the system. Our results showed that the endogenous factor TGF-β1 could be controllably secreted to suppress the intestinal inflammatory response. Additionally, regulatory secretion of IFN-γ was promoted to slow the progression of B16F10 tumor.

Intertwined mechanisms define transport of anti-ICAM nanocarriers across the endothelium and brain delivery of a therapeutic enzyme

The interaction of drug delivery systems with tissues is key for their application. An example is drug carriers targeted to endothelial barriers, which can be transported to intra-endothelial compartments (lysosomes) or transcellularly released at the tissue side (transcytosis). Although carrier targeting valency influences this process, the mechanism is unknown. We studied this using polymer nanocarriers (NCs) targeted to intercellular adhesion molecule-1 (ICAM-1), an endothelial-surface glycoprotein whose expression is increased in pathologies characterized by inflammation. A bell-shaped relationship was found between NC targeting valency and the rate of transcytosis, where high and low NC valencies rendered less efficient transcytosis rates than an intermediate valency formulation. In contrast, an inverted bell-shape relationship was found for NC valency and lysosomal trafficking rates. Data suggested a model where NC valency plays an opposing role in the two sub-processes involved in transcytosis: NC binding-uptake depended directly on valency and exocytosis-detachment was inversely related to this parameter. This is because the greater the avidity of the NC-receptor interaction the more efficient uptake becomes, but NC-receptor detachment post-transport is more compromised. Cleavage of the receptor at the basolateral side of endothelial cells facilitated NC transcytosis, likely by helping NC detachment post-transport. Since transcytosis encompasses both sets of events, the full process finds an optimum at the intersection of these inverted relationships, explaining the bell-shaped behavior. NCs also trafficked to lysosomes from the apical side and, additionally, from the basolateral side in the case of high valency NCs which are slower at detaching from the receptor. This explains the opposite behavior of NC valency for transcytosis vs. lysosomal transport. Anti-ICAM NCs were verified to traffic into the brain after intravenous injection in mice, and both cellular and in vivo data showed that intermediate valency NCs resulted in higher delivery of a therapeutic enzyme, acid sphingomyelinase, required for types A and B Niemann-Pick disease.

Enhanced Oral Vaccine Efficacy of Polysaccharide-Coated Calcium Phosphate Nanoparticles

Oral administration of vaccines has been limited due to low immune response compared to parenteral administration. Antigen degradation in the acidic gastrointestinal environment (GI), mucus barriers, and inefficient cellular uptake by immune cells are the major challenges for oral vaccine delivery. To solve these issues, the current study investigates calcium phosphate nanoparticles (CaP NPs) coated with polysaccharides as nanocarriers for oral protein antigen delivery. In this design, the CaP NP core had an optimized antigen encapsulation capacity of 90 mg (BSA-FITC)/g (CaP NPs). The polysaccharides chitosan and alginate were coated onto the CaP NPs to protect the antigens against acidic degradation in the GI environment and enhance the immune response in the small intestine. The antigen release profiles showed that alginate-chitosan-coated CaP NPs prevented antigen release in a simulated gastric fluid (pH 1.2), followed by sustained release in simulated intestinal (pH 6.8) and colonic (pH 7.4) fluids. Cellular uptake and macrophage stimulation data revealed that the chitosan coating enhanced antigen uptake by intestine epithelia cells (Caco-2) and macrophages and improved surface expression of costimulatory molecules on macrophages. In vivo test further demonstrated that oral administration of alginate-chitosan-coated CaP@OVA NPs significantly enhanced the mucosal IgA and serum IgG antibody responses as compared to naked OVA, indicating that the CaP-Chi-Alg nanoparticle can potentially be used as a promising oral vaccine delivery system.

Cu(II)-Metallacryptands Self-Assembled to Vesicular Aggregates Capable of Encapsulating and Transporting an Anticancer Drug Inside Cancer Cells

Crystallographically characterized M₂ L₄ type cationic Cu(II)-metallacryptands [MC(X)] derived from a series of bis-pyridyl-bis-urea ligands (L_X ; X = O, S, C) are self-assembled to single-layered vesicular aggregates in DMSO, DMSO/water, and DMSO/DMEM (biological media). One such vesicle is MC(O)-vesicle that is demonstrated to be able to load and release (pH responsive) an anticancer drug, namely doxorubicin hydrochloride (DOX). DOX-loaded MC(O)-vesicle is also successfully transported within MDA-MB-231 cells-a highly aggressive human breast cancer cell line. Such self-assembling behavior to form vesicular aggregates by metallacryptands (MCs) is hitherto unknown.

Recent Advancements in Using Polymers for Intestinal Mucoadhesion and Mucopenetration

Oral administration of actives is the most desired form of delivery, but the formulations need to overcome a variety of barriers including the intestinal mucus. This feature article summarizes the developments from the past 2-3 years in this context focusing on polymer-based formulations. The progress in assembling mucopenetrating nanoparticles is outlined considering coatings using noninteracting polymers as well as virus-like particles and charge-shifting particles. Next, polymers and their modification to enhance mucoadhesion are discussed, followed by providing examples of double-encapsulation systems that aim to combine mucopenetration with mucoadhesion in the same formulation. Finally, a short outlook is provided highlighting a few of the most pressing challenges to address.

Investigation Of Vitamin B12-Modified Amphiphilic Sodium Alginate Derivatives For Enhancing The Oral Delivery Efficacy Of Peptide Drugs

Purpose

Peptide drugs have been used in therapy various diseases. However, the poor bioavailability of peptide drugs for oral administration has limited their clinical applications, on account of the acidic environment and digestive enzymes inside the human gastrointestinal tract. To enhance stability in the human gastrointestinal tract, bioavailability, and targeted drug delivery of peptide drugs through oral administration, a vitamin B₁₂-modified amphiphilic sodium alginate derivative (CSAD-VB₁₂) was synthesized.

Materials and methods

A vitamin B₁₂-modified amphiphilic sodium alginate derivative (CSAD-VB₁₂) was synthesized via the N,N'-dicyclohexylcarbodiimide active method at room temperature, and then characterized using FTIR and ¹H NMR spectroscopy. Insulin was used as a model peptide drug and the insulin-loaded CSAD-VB₁₂ (CSAD-VB₁₂/insulin) nanoparticles with negative zeta potentials were prepared in PBS (pH=7.4). Scanning electron microscopy was used to observe CSAD-VB₁₂/insulin as spherical nanoparticles. The CSAD-VB₁₂ derivatives and CSAD-VB₁₂/insulin nanoparticles displayed nontoxicity towards the human colon adenocarcinoma (Caco-2) cells by CCK-8 test. Caco-2 cell model was used to measure the apparent permeability (Papp) of insulin, CSAD/insulin and CSAD-VB₁₂/insulin. Furthermore, confocal was used to confirm the endocytosis of intestinal enterocytes. Type 1 diabetes mice were used to evaluate the intestinal absorption and retention effect of test nanoparticles.

Results

They were observed as spherical nanoparticles in the size of 30-50 nm. The CSAD-VB₁₂ derivatives and CSAD-VB₁₂/insulin nanoparticles displayed nontoxicity towards the human colon adenocarcinoma (Caco-2) cells. Comparing with insulin and the CSAD/insulin nanoparticles, the CSAD-VB₁₂/insulin nanoparticles exhibited higher permeation ability through intestinal enterocytes in the Caco-2 cell model. Oral administration of the CSAD-VB₁₂/insulin nanoparticles to Type 1 diabetic mice yields higher intestinal retention effect, targeted absorption, and outstanding efficacy.

Conclusion

CSAD-VB₁₂ derivatives enhance the small intestinal absorption efficacy and retention of peptide by oral administration, which indicated that it could be a promising candidate for oral peptide delivery in the prospective clinical application.

Thermo-responsive polymers: Applications of smart materials in drug delivery and tissue engineering

Synthetic polymers are attracting great attention in the last decades for their use in the biomedical field as nanovectors for controlled drug delivery, hydrogels and scaffolds enabling cell growth. Among them, polymers able to respond to environmental stimuli have been recently under growing consideration to impart a "smart" behavior to the final product, which is highly desirable to provide it with a specific dynamic and an advanced function. In particular, thermo-responsive polymers, materials able to undergo a discontinuous phase transition or morphological change in response to a temperature variation, are among the most studied. The development of the so-called controlled radical polymerization techniques has paved the way to a high degree of engineering for the polymer architecture and properties, which in turn brought to a plethora of sophisticated behaviors for these polymers by simply switching the external temperature. These can be exploited in many different fields, from separation to advanced optics and biosensors. The aim of this review is to critically discuss the latest advances in the development of thermo-responsive materials for biomedical applications, including a highly controlled drug delivery, mediation of cell growth and bioseparation. The focus is on the structural and design aspects that are required to exploit such materials for cutting-edge applications in the biomedical field.

Gastric environment-stable oral nanocarriers for in situ colorectal cancer therapy

Colorectal cancer (CRC) is a prevalent and fatal cancer. Oral administration provided the potential for in situ treatment of the colorectal cancer. However, drugs couldn't be well-absorbed mainly due to its degradation in the gastric area and poor intestinal permeability. In this study, we synthesized deoxycholic acid and hydroxybutyl decorated chitosan nanoparticles (DAHBC NPs) as oral curcumin (CUR) delivery system for colorectal cancer treatment. DAHBC with lower critical solution temperature (LCST) below 37 °C (27-33 °C) was obtained. DAHBC NPs were correspondingly stable in simulated gastric conditions (pH 1.2, 37 °C), due to the offset of size change between pH-responsive expansion and thermo-responsive shrinkage. In simulated intestinal tract (pH 7.0-7.4, 37 °C), DAHBC NPs exhibited burst release of CUR owing to the onefold effect of thermo-responsive shrinkage. DAHBC27 NPs showed the minimum CUR leakage (~10%) in simulated gastric conditions, because a furthest temperature-sensitive shrinkage caused by the lowest LCST offset the expansion in acid environment. DAHBC27 NPs induced ~10-fold increased (P < 0.05) CUR absorption by paracellular transport pathway, compared to the free CUR. Thus, DAHBC NPs stabilized in the gastric environment may be a promising oral drugs delivery system for effective in situ colorectal cancer therapy.

Construction of catechol-grafted chitosan alginate/barium sulfate microcapsules for computed tomography real-time imaging and gastroretentive drug delivery

Background: The gastroretentive drug delivery system is an effective administration route, which can improve the bioavailability of the drug and the therapeutic effect by prolonging the release time of the drug and controlling the release rate in the stomach. Methods: Inspired by the excellent adhesion properties of mussel protein, we prepared novel catechol-grafted chitosan alginate/barium sulfate microcapsules (Cat-CA/BS MCs) with mucoadhesive properties and computed tomography (CT) imaging function for gastric drug delivery. First, barium sulfate nanoclusters used as CT contrast agent were synthesized in situ in the Cat-CA/BS MCs through a one-step electronic spinning method. Next, catechol-grafted chitosan as the mucoadhesive moiety was coated on the surface of Cat-CA/BS MCs by polyelectrolyte molecule self-assembly. Results: The prepared Cat-CA/BS MCs could effectively retained in the stomach for 48 hours and successively released ranitidine hydrochloride, which could be used for the treatment of gastric ulcer. Cat-CA/BS MCs exhibited superior CT contrast imaging properties for real-time tracking in vivo after oral administration. Conclusion: These findings demonstrate that Cat-CA/BS MCs serving as multifunctional oral drug carriers possess huge potential in gastroretentive drug delivery and non-invasive visualization.