A thiolated oxidized guar gum and sodium lginate dual-network microspheres with enhanced gastric acid resistance and mucoadhesion for delivery of probiotics.

Probiotics offer numerous beneficial functions for human bodies, while the low survival rate under gastric acid and short retention time in the intestine are the major obstacles to their utilization. To address these issues, we designed a novel dual-network hydrogel microsphere that combines gastric acid resistance with enhanced mucoadhesion, aiming for the targeted delivery of probiotics. Thiolated oxidized guar gum (SOGG) was disulfide-linked to form the first network, and sodium alginate (SA) was cross-linked with Ca2+ to form the second network. Under the protection of the interpenetrating dual network microspheres, a much higher viability of Lactobacillus rhamnosus (LGG) (8.73 log CFU/mL) was achieved in simulated gastric fluid, compared to the zero-survival rate of free LGG. Mucoadhesion tests showed that the adhesion rate of SOGG/SA microspheres to the intestinal mucosa was 1.75 times higher than that of thiol-free microspheres. In vivo studies revealed that LGG-loaded microspheres significantly enhanced intestinal barrier function, remodeled the gut microbiome, and alleviated DSS-induced colitis in mice. Overall, SOGG/SA microspheres provide an effective strategy to the challenges of probiotic reduction in the stomach and rapid expulsion from the intestines, enhancing their health benefits.

Intranasal mRNA-LNP vaccination protects hamsters from SARS-CoV-2 infection.

Intranasal vaccination represents a promising approach for preventing disease caused by respiratory pathogens by eliciting a mucosal immune response in the respiratory tract that may act as an early barrier to infection and transmission. This study investigated immunogenicity and protective efficacy of intranasally administered messenger RNA (mRNA)-lipid nanoparticle (LNP) encapsulated vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Syrian golden hamsters. Intranasal mRNA-LNP vaccination systemically induced spike-specific binding [immunoglobulin G (IgG) and IgA] and neutralizing antibodies. Intranasally vaccinated hamsters also had decreased viral loads in the respiratory tract, reduced lung pathology, and prevented weight loss after SARS-CoV-2 challenge. Together, this study demonstrates successful immunogenicity and protection against respiratory viral infection by an intranasally administered mRNA-LNP vaccine.

Improvement of the UV-resistance capability of fish gelatin-oxidized starch film via inserting mycosporine-like amino acids.

BACKGROUND: Mycosporine-like amino acids (MAAs) are known as the strongest solar guardians in nature. RESULTS: In the present study, the extraction of MAAs from dried Pyropia haitanensis was achieved. Fish gelatin and oxidized starch composite films embedded with MAAs (0-0.3% w/w) were fabricated. The maximum absorption wavelength of the composite film appeared at 334 nm, which was consistent with MAA solution. Furthermore, the UV absorption intensity of the composite film was highly dependent on the concentration of MAAs. The composite film exhibited excellent stability during the 7-day storage period. The physicochemical features of composite film were demonstrated by the measurement of water content, water vapor transmission rate, oil transmission, and visual characteristics. Furthermore, in the actual anti-UV effect investigation, the increase in peroxide value and the acid value of grease under the films coverage was delayed. In the meantime, the decrease in ascorbic acid content in dates was postponed, and survivability of Escherichia coli was increased. CONCLUSION: Our results suggest that fish gelatin-oxidized starch-mycosporine-like amino acids film (FOM film) with biodegradable and anti-ultraviolet properties has a high potential for usage in food packaging materials. © 2023 Society of Chemical Industry.

Preparation and Properties of Salecan-Soy Protein Isolate Composite Hydrogel Induced by Thermal Treatment and Transglutaminase.

Salecan (Sal) is a novel marine microbial polysaccharide. In the present research, Sal and soy protein isolate (SPI) were adopted to fabricate Sal-SPI composite hydrogel based on a stepwise process (thermal treatment and transglutaminase induction). The effect of Sal concentration on morphology, texture properties, and the microstructure of the hydrogel was evaluated. As Sal concentration varied from 0.4 to 0.6 wt%, hydrogel elasticity increased from 0.49 to 0.85 mm. Furthermore, the internal network structure of Sal-SPI composite hydrogel also became denser and more uniform as Sal concentration increased. Rheological studies showed that Sal-SPI elastic hydrogel formed under the gelation process. Additionally, FTIR and XRD results demonstrated that hydrogen bonds formed between Sal and SPI molecules, inferring the formation of the interpenetrating network structure. This research supplied a green and simple method to fabricate Sal-SPI double network hydrogels.

Synthesis and Rheological Characterization of a Novel Salecan Hydrogel.

Salecan (Sal) is a novel microbial polysaccharide. In the present research, thermal treatment was performed to fabricate Sal hydrogel. The effect of Sal concentration on water holding capacity, swelling properties, texture properties, and microstructure of the hydrogels was discussed. It was found that the equilibrium degree of swelling (EDS) of Sal hydrogels was above 1500%, inferred Sal was a highly hydrophilic polysaccharide. As Sal concentration increased from 3.5 to 8.0 wt%, the hardness increased from 0.88 to 2.07 N and the water hold capability (WHC) increased from 91.3% to 98.2%. Furthermore, the internal network structure of Sal hydrogel also became denser and more uniform. Rheological studies suggested that elastic hydrogel formed under the gelation process. All these results demonstrated that Sal hydrogel prepared by thermal treatment had good gelling properties, which opened up a new safe way for the preparation of Sal hydrogel and broadened the application range of Sal.

The Preparation of Anti-Ultraviolet Composite Films Based on Fish Gelatin and Sodium Alginate Incorporated with Mycosporine-like Amino Acids.

Mycosporine-like amino acids (MAAs) are ultraviolet-absorbing compounds and have antioxidant functions. In this paper, MAAs were added into fish gelatin/sodium alginate films as an anti-ultraviolet additive. The effects of 0-5% MAAs (w/w, MAAs/fish gelatin) on the physical properties, antioxidant properties, antibacterial properties and anti-ultraviolet properties of fish gelatin/sodium alginate films were investigated. The results suggest that the content of the MAAs influenced the mechanical properties. The water content, swelling and water vapor permeability of the films were not altered with the addition of MAAs. In addition, the composite films showed effective antioxidant activity and antimicrobial activity. The incorporation of MAAs significantly improved the DPPH radical scavenging activity of the films from 35.77% to 46.61%. Moreover, the block ultraviolet rays' ability was also greatly improved when the film mixed with the MAAs and when the value of the light transmission was 0.6% at 350 nm. Compared with the pure composite film, the growth of E. coli covered by the composite film with 3.75% and 5% MAAs exhibited the best survival rate. These results reveal that MAAs are a good film-forming substrate, and MAAs have good potential to prepare anti-ultraviolet active films and antioxidant active films for applications. Overall, this project provides a theoretical basis for the study of active composite films with anti-ultraviolet activities, and it provides new ideas for the application of MAAs.

Impact of Sequence Specificity of Spherical Nucleic Acids on Macrophage Activation in Vitro and in Vivo.

The effects of spherical nucleic acid (SNA) gold nanoparticle conjugates on the activation of macrophages in vitro and release of cytokines in vivo were explored. Herein, we show that G-quadruplexes, the formation of which is enhanced on gold nanoparticle surfaces, elicit an increase in cytokine release from mouse and human macrophages and induce the upregulation of activation receptors as well as NO2 production in vitro. Moreover, these G-rich SNAs can induce cytokine release when injected intravenously, though there were no severe, long-term effects observed. These results further reinforce the notion that nucleic acid sequence and structure play an important role in how SNAs interact in biological milieu and highlight a key design parameter.

RNA-Based Immunostimulatory Liposomal Spherical Nucleic Acids as Potent TLR7/8 Modulators.

Immunostimulatory spherical nucleic acids (IS-LSNAs) comprised of RNA selective for toll-like receptors (TLRs) 7/8 are synthesized and characterized. These structures consist of liposomal cores functionalized with a dense shell of RNA inserted into the wall of the lipid core via hydrophobic cholesterol moieties. IS-LSNAs potently activate TLR7/8 via NF-κΒ signaling in reporter cell lines and in primary immune cells as evidenced by cytokine production and the upregulation of costimulatory receptors. Importantly, they are preferentially taken up by plasmacytoid dendritic cells, an observation that makes them potentially useful for immunotherapy. In addition, these structures contain a core that can be loaded with antigens and used to prime T cells. In this regard, it is shown that dendritic cells treated with IS-SNAs loaded with ovalbumin peptide can prime ova specific CD8+ T cells. In addition to introducing the first IS-LSNAs consisting of RNA, these experiments show that one can facilitate an antigen-specific T cell response greater than that of free or cationic lipid-transfected RNA of the same sequence selective for TLR7/8. This work points toward the promise of using IS-LSNAs comprised of RNA as potent and highly tunable TLR-specific agents for the development of vaccines and other pharmaceuticals that require selective immunomodulation.

The Impact of Protein Corona Formation on the Macrophage Cellular Uptake and Biodistribution of Spherical Nucleic Acids.

The effect of serum protein adsorption on the biological fate of Spherical Nucleic Acids (SNAs) is investigated. Through a proteomic analysis, it is shown that G-quadruplexes templated on the surface of a gold nanoparticle in the form of SNAs mediate the formation of a protein corona that is rich in complement proteins relative to SNAs composed of poly-thymine (poly-T) DNA. Cellular uptake studies show that complement receptors on macrophage cells recognize the SNA protein corona, facilitating their internalization, and causing G-rich SNAs to accumulate in the liver and spleen more than poly-T SNAs in vivo. These results support the conclusion that nucleic acid sequence and architecture can mediate nanoparticle-biomolecule interactions and alter their cellular uptake and biodistribution properties and illustrate that nucleic acid sequence is an important parameter in the design of SNA therapeutics.

Nanoflares as probes for cancer diagnostics.

Patients whose cancer is detected early are much more likely to have a positive prognosis and outcome. Nanoflares hold promise as a practical diagnostic platform for the early detection of cancer markers in living cells. These probes are based on spherical nucleic acid (SNAs) and are typically composed of gold nanoparticle cores and densely packed and highly oriented oligonucleotide shells; these sequences are complementary to specific mRNA targets and are hybridized to fluorophore-labeled reporter strands. Nanoflares take advantage of the highly efficient fluorescence quenching properties of gold, the rapid cellular uptake of SNAs that occurs without the use of transfection agents, and the enzymatic stability of such constructs to report a highly sensitive and specific signal in the presence of intracellular target mRNA. In this chapter, we will focus on the synthesis, characterization, and diagnostic applications of nanoflares as they relate to cancer markers.

Spherical nucleic acid nanoparticle conjugates enhance G-quadruplex formation and increase serum protein interactions.

To understand the effect of three-dimensional oligonucleotide structure on protein corona formation, we studied the identity and quantity of human serum proteins that bind to spherical nucleic acid (SNA) nanoparticle conjugates. SNAs exhibit cellular uptake properties that are remarkably different from those of linear nucleic acids, which have been related to their interaction with certain classes of proteins. Through a proteomic analysis, this work shows that the protein binding properties of SNAs are sequence-specific and supports the conclusion that the oligonucleotide tertiary structure can significantly alter the chemical composition of the SNA protein corona. This knowledge will impact our understanding of how nucleic acid-based nanostructures, and SNAs in particular, function in complex biological milieu.