Dictating the spatial-temporal delivery of molecular adjuvant and antigen for the enhanced vaccination.

The incorporation of molecular adjuvants has revolutionized vaccine by boosting overall immune efficacy. While traditional efforts have been concentrated on the quality and quantity of vaccine components, the impact of adjuvant and antigen delivery kinetics on immunity remains to be fully understood. Here, we employed poly (lactic-co-glycolic acid) nanoparticle (PLGA NP) -stabilized Pickering emulsion (PPE) to refine the delivery kinetics of molecular adjuvant CpG and antigen, aiming to optimize immune responses. The hierarchical structure of PPE enabled spatially differential loading of CpG and antigen. The component inserted on the oil-water interphase exhibited a rapid release profile, while the one encapsulated in the PLGA NPs demonstrated a sustained release. This led to distinct intracellular spatial-temporal release kinetics. Compared to the PPE with sustained CpG release and burst release of antigen, we found that the PPE with rapid CpG release and sustained antigen release triggered an early and robust activation of Toll-like receptor 9 (TLR9) in direct way. This fostered a more immunogenic microenvironment, significantly outperforming the inverted delivery profile in dendritic cells (DCs) activation, resulting in higher CD40 expression, elevated proinflammatory cytokine levels, sustained antigen cross-presentation, an enhanced Th1 response, and increased CD8+ T cells. Moreover, prior exposure of CpG led to suppressed tumor growth and enhanced efficacy in Varicella-zoster virus (VZV) vaccine. Our findings underscore the importance of tuning adjuvant and antigen delivery kinetics in vaccine design, proposing a novel path for enhancing vaccination outcomes.

Effect of transcutaneous electrical nerve stimulation based on wrist-ankle acupuncture theory for pain relief during colonoscopy without anesthesia: a randomized controlled trial.

BACKGROUND: Colonoscopy is essential for diagnosing colorectal diseases but can cause pain during the procedure. This study explored the analgesic effects of transcutaneous electrical nerve stimulation based on wrist-ankle acupuncture theory (TENS-WAA) in colonoscopy without anesthesia. METHODS: This prospective study included 120 participants undergoing colonoscopies without anesthesia. The trial group received low-frequency, high-intensity TENS-WAA adjusted to the maximum tolerable current, while the control group received minimal current. The primary outcome was the retrospective pain score on a visual analog scale (VAS). Secondary outcomes included time, heart rate, and credibility/expectancy questionnaire (CEQ) scores. RESULTS: Participants who received TENS-WAA reported significantly lower pain VAS scores than the control group (estimated median difference -1.1, 95%CI -2 to -0.4; P = 0.002). Male participants in the trial group experienced significantly lower pain scores than the control group (mean difference -1.4, 95%CI -2.41 to -0.39; P = 0.008). The trial group showed significantly less variation in heart rates (P<0.001) and higher CEQ scores (P = 0.001) than the control group. No adverse events were reported. CONCLUSION: TENS-WAA effectively reduced pain during colonoscopy without anesthesia, especially in male participants, providing a promising noninvasive analgesic method.

Unlocking the Therapeutic Applicability of LNP-mRNA: Chemistry, Formulation, and Clinical Strategies.

Messenger RNA (mRNA) has emerged as an innovative therapeutic modality, offering promising avenues for the prevention and treatment of a variety of diseases. The tremendous success of mRNA vaccines in effectively combatting coronavirus disease 2019 (COVID-19) evidences the unlimited medical and therapeutic potential of mRNA technology. Overcoming challenges related to mRNA stability, immunogenicity, and precision targeting has been made possible by recent advancements in lipid nanoparticles (LNPs). This review summarizes state-of-the-art LNP-mRNA-based therapeutics, including their structure, material compositions, design guidelines, and screening principles. Additionally, we highlight current preclinical and clinical trends in LNP-mRNA therapeutics in a broad range of treatments in ophthalmological conditions, cancer immunotherapy, gene editing, and rare-disease medicine. Particular attention is given to the translation and evolution of LNP-mRNA vaccines into a broader spectrum of therapeutics. We explore concerns in the aspects of inadequate extrahepatic targeting efficacy, elevated doses, safety concerns, and challenges of large-scale production procedures. This discussion may offer insights and perspectives on near- and long-term clinical development prospects for LNP-mRNA therapeutics.

Augmenting vaccine efficacy: Tailored immune strategy with alum-stabilized Pickering emulsion.

BACKGROUND: The achievement of optimal vaccine efficacy is contingent upon the collaborative interactions between T and B cells in adaptive immunity. Although multiple immunization strategies have been proposed, there is a notable scarcity of comprehensive investigations pertaining to enhance immune effects through immune strategy adjustments for individual vaccine. METHODS: The hierarchically structured aluminum hydroxide microgel-stabilized Pickering emulsion (ASPE) was prepared by ultrasonic method. This study explored the influence of the immune strategy of ASPE to immune responses, including antigen exposure pattern, adjuvants and antigen dosage, and administration interval. RESULTS: The findings revealed that external antigen adsorption facilitated increased exposure of antigen epitopes, leading to elevated IgG titers and secretion of cytokines such as interferon-gamma (IFN-γ) or interleukin-4 (IL-4). Additionally, even a low dose (1 µg/dose) of antigens of ASPE boosted sufficient neutralizing antibody levels and memory T cells compared to high-dose antigens, which consistent with the adjuvant dosage effect. Furthermore, maintaining a 4-week immunization interval yielded optimal levels of antigen-specific IgG titers in both short-term and long-term scenarios, as compared to intervals of 2, 3, and 5 weeks. A consistent trend was observed in the proliferation of memory B cells, reaching a superior level at the 4-week interval, which could enhance protection against viral re-infection. CONCLUSION: Tailoring immunization strategies for specific vaccines has emerged as powerful driver in maximizing vaccine efficacy and eliciting robust immune responses, thereby presenting cutting-edge approaches to enhanced vaccination.

Staphylococcus Aureus Membrane Vesicles Kill Tumor Cells Through a Caspase-1-Dependent Pyroptosis Pathway.

Introduction: Nanosized outer membrane vesicles (OMVs) from Gram-negative bacteria have attracted increasing interest because of their antitumor activity. However, the antitumor effects of MVs isolated from Gram-positive bacteria have rarely been investigated. Methods: MVs of Staphylococcus aureus USA300 were prepared and their antitumor efficacy was evaluated using tumor-bearing mouse models. A gene knock-in assay was performed to generate luciferase Antares2-MVs for bioluminescent detection. Cell counting kit-8 and lactic dehydrogenase release assays were used to detect the toxicity of the MVs against tumor cells in vitro. Active caspase-1 and gasdermin D (GSDMD) levels were determined using Western blot, and the tumor inhibition ability of MVs was determined in B16F10 cells treated with a caspase-1 inhibitor. Results: The vesicular particles of S. aureus USA300 MVs were 55.23 ± 8.17 nm in diameter, and 5 µg of MVs remarkably inhibited the growth of B16F10 melanoma in C57BL/6 mice and CT26 colon adenocarcinoma in BALB/c mice. The bioluminescent signals correlated well with the concentrations of the engineered Antares2-MVs (R2 = 0.999), and the sensitivity for bioluminescence imaging was 4 × 10-3 µg. Antares2-MVs can directly target tumor tissues in vivo, and 20 µg/mL Antares2-MVs considerably reduced the growth of B16F10 and CT26 tumor cells, but not non-carcinomatous bEnd.3 cells. MV treatment substantially increased the level of active caspase-1, which processes GSDMD to trigger pyroptosis in tumor cells. Blocking caspase-1 activation with VX-765 significantly protected tumor cells from MV killing in vitro and in vivo. Conclusion: S. aureus MVs can kill tumor cells by activating the pyroptosis pathway, and the induction of pyroptosis in tumor cells is a promising strategy for cancer treatment.

LysSYL: a broad-spectrum phage endolysin targeting Staphylococcus species and eradicating S. aureus biofilms.

BACKGROUND: Staphylococcus aureus and its single or mixed biofilm infections seriously threaten global public health. Phage therapy, which uses active phage particles or phage-derived endolysins, has emerged as a promising alternative strategy to antibiotic treatment. However, high-efficient phage therapeutic regimens have yet to be established. RESULTS: In this study, we used an enrichment procedure to isolate phages against methicillin-resistant S. aureus (MRSA) XN108. We characterized phage SYL, a new member of the Kayvirus genus, Herelleviridae family. The phage endolysin LysSYL was expressed. LysSYL demonstrated stability under various conditions and exhibited a broader range of efficacy against staphylococcal strains than its parent phage (100% vs. 41.7%). Moreover, dynamic live/dead bacterial observation demonstrated that LysSYL could completely lyse MRSA USA300 within 10 min. Scan and transmission electron microscopy revealed evident bacterial cell perforation and deformation. In addition, LysSYL displayed strong eradication activity against single- and mixed-species biofilms associated with S. aureus. It also had the ability to kill bacterial persisters, and proved highly effective in eliminating persistent S. aureus when combined with vancomycin. Furthermore, LysSYL protected BALB/c mice from lethal S. aureus infections. A single-dose treatment with 50 mg/kg of LysSYL resulted in a dramatic reduction in bacterial loads in the blood, liver, spleen, lungs, and kidneys of a peritonitis mouse model, which resulted in rescuing 100% of mice challenged with 108 colony forming units of S. aureus USA300. CONCLUSIONS: Overall, the data provided in this study highlight the strong therapeutic potential of endolysin LysSYL in combating staphylococcal infections, including mono- and mixed-species biofilms related to S. aureus.

Sub-MIC vancomycin enhances the antibiotic tolerance of vancomycin-intermediate Staphylococcus aureus through downregulation of protein succinylation.

Bacteria develop tolerance after transient exposure to antibiotics, and tolerance is a significant driver of resistance. The purpose of this study is to evaluate the mechanisms underlying tolerance formation in vancomycin-intermediate Staphylococcus aureus (VISA) strains. VISA strains were cultured with sub-minimum inhibitory concentrations (sub-MICs) of vancomycin. Enhanced vancomycin tolerance was observed in VISA strains with distinct genetic lineages. Western blot revealed that the VISA protein succinylation (Ksucc) levels decreased with the increase in vancomycin exposure. Importantly, Ksucc modification, vancomycin tolerance, and cell wall synthesis were simultaneously affected after deletion of SacobB, which encodes a desuccinylase in S. aureus. Several Ksucc sites were identified in MurA, and vancomycin MIC levels of murA mutant and Ksucc-simulated (MurA(K69E) and MurA(K191E)) mutants were reduced. The vancomycin MIC levels of K65-MurA(K191E) in particular decreased to 1 mg/L, converting VISA strain K65 to a vancomycin-susceptible S. aureus strain. We further demonstrated that the enzymatic activity of MurA was dependent on Ksucc modification. Our data suggested the influence of vancomycin exposure on bacterial tolerance, and protein Ksucc modification is a novel mechanism in regulating vancomycin tolerance.

Confining the Growth of AgNPs onto Epigallocatechin Gallate-Decorated Zein Nanoparticles for Constructing Potent Protein-Based Antibacterial Nanocomposites.

Sliver nanoparticles (AgNPs) have attracted tremendous interest as an alternative to commercially available antibiotics due to their low microbial resistance and broad-spectrum antimicrobial activity. However, AgNPs are highly reactive and unstable and are susceptible to fast oxidation. Synthesizing stable and efficient AgNPs using green chemistry principles remains a major challenge. To address this issue, we establish a facile route to form AgNP-doped zein nanoparticle core-satellite superstructures with ultralow minimum bactericidal concentration (MBC). In brief, polyphenol surface-functionalization of zein nanoparticles was performed, and the epigallocatechin gallate (EGCG) layer on zein nanoparticles served as a reducing-cum-stabilizing agent. We used EGCG-decorated zein nanoparticles (ZE) as a template to direct the nucleation and growth of AgNPs to develop metallized hybrid nanoparticles (ZE-Ag). The highly monodispersed core-satellite nanoparticles (∼150 nm) decorated with ∼4.9 nm AgNPs were synthesized successfully. The spatial restriction of EGCG by zein nanoparticles confined the nucleation and growth of AgNPs only on the surface of the particles, which prevented the formation of entangled clusters of polyphenols and AgNPs and concomitantly inhibited the coalescence and oxidation of AgNPs. Thus, this strategy improved the effective specific surface area of AgNPs, and as a result, ZE-Ag efficiently killed the indicator bacteria, Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus(MRSA) after 20 min of incubation, with MBCs of 2 and 4 µg/mL, respectively. This situation indicated that as-prepared core-satellite nanoparticles possessed potent short-term sterilization capability. Moreover, the simulated wound infection model also confirmed the promising application of ZE-Ag as an efficient antimicrobial composite. This work provides new insights into the synthesis and emerging application of AgNPs in food preservation, packaging, biomedicine, and catalysis.

Loaded delta-hemolysin shapes the properties of Staphylococcus aureus membrane vesicles.

Background: Membrane vesicles (MVs) are nanoscale vesicular structures produced by bacteria during their growth in vitro and in vivo. Some bacterial components can be loaded in bacterial MVs, but the roles of the loaded MV molecules are unclear. Methods: MVs of Staphylococcus aureus RN4220 and its derivatives were prepared. Dynamic light scattering analysis was used to evaluate the size distribution, and 4D-label-free liquid chromatography-tandem mass spectrometry analysis was performed to detect protein composition in the MVs. The site-mutation S. aureus RN4220-Δhld and agrA deletion mutant RN4220-ΔagrA were generated via allelic replacement strategies. A hemolysis assay was performed with rabbit red blood cells. CCK-8 and lactate dehydrogenase release assays were used to determine the cytotoxicity of S. aureus MVs against RAW264.7 macrophages. The serum levels of inflammatory factors such as IL-6, IL-1ß, and TNFα in mice treated with S. aureus MVs were detected with an enzyme-linked immunosorbent assay kit. Results: Delta-hemolysin (Hld) was identified as a major loaded factor in S. aureus MVs. Further study showed that Hld could promote the production of staphylococcal MVs with smaller sizes. Loaded Hld affected the diversity of loaded proteins in MVs of S. aureus RN4220. Hld resulted in decreased protein diversity in MVs of S. aureus. Site-mutation (RN4220-Δhld) and agrA deletion (RN4220-ΔagrA) mutants produced MVs (ΔhldMVs and ΔagrAMVs) with a greater number of bacterial proteins than those derived from wild-type RN4220 (wtMVs). Moreover, Hld contributed to the hemolytic activity of wtMVs. Hld-loaded wtMVs were cytotoxic to macrophage RAW264.7 cells and could stimulate the production of inflammatory factor IL-6 in vivo. Conclusion: This study presented that Hld was a major loaded factor in S. aureus MVs, and the loaded Hld played vital roles in the MV-property modification.

Optimizing a high-sensitivity NanoLuc-based bioluminescence system for in vivo evaluation of antimicrobial treatment.

Focal and systemic infections are serious threats to human health. Preclinical models enable the development of new drugs and therapeutic regimens. In vivo, animal bioluminescence (BL) imaging has been used with bacterial reporter strains to evaluate antimicrobial treatment effects. However, high-sensitivity bioluminescent systems are required because of the limited tissue penetration and low brightness of the BL signals of existing approaches. Here, we report that NanoLuc (Nluc) showed better performance than LuxCDABE in bacteria. However, the retention rate of plasmid constructs in bacteria was low. To construct stable Staphylococcus aureus reporter strains, a partner protein enolase (Eno) was identified by screening of S. aureus strain USA300 for fusion expression of Nluc-based luciferases, including Nluc, Teluc, and Antares2. Different substrates, such as hydrofurimazine (HFZ), furimazine (FUR), and diphenylterazine (DTZ), were used to optimize a stable reporter strain/substrate pair for BL imaging. S. aureus USA300/Eno-Antares2/HFZ produced the highest number of photons of orange-red light in vitro and enabled sensitive BL tracking of S. aureus in vivo, with sensitivities of approximately 10 CFU from mouse skin and 750 CFU from mouse kidneys. USA300/Eno-Antares2/HFZ was a powerful combination based on the longitudinal evaluation of the therapeutic efficacy of antibiotics. The optimized S. aureus Eno-Antares2/HFZ pair provides a technological advancement for the in vivo evaluation of antimicrobial treatment.

Static analysis of elastic cable structures under mechanical load using discrete catenary theory.

In this paper, the nonlinear mechanical response of elastic cable structures under mechanical load is studied based on the discrete catenary theory. A cable net is discretized into multiple nodes and edges in our numerical approach, which is followed by an analytical formulation of the elastic energy and the associated Hessian matrix to realize the dynamic simulation. A fully implicit framework is proposed based on the discrete differential geometry (DDG) theory. The equilibrium configuration of a target object is derived by adding damping force into the system, known as the dynamic relaxation method. The mechanical response of a single suspended cable is investigated and compared with the analytical solution for cross-validation. A more intricate scenario is further discussed in detail, where a structure consisting of multiple slender cables is connected through joints. Utilizing the robustness and efficiency of our discrete numerical framework, a systematic parameter sweep is performed to quantify the force displacement relationships of nets with the different number of cables and different directions of fibers. Finally, an empirical scaling law is provided to account for the rigidity of elastic cable net in terms of its geometric properties, material characteristics, component numbers, and cable orientations. Our results would provide new insight in revealing the connections between flexible structures and tensegrity structures, and could motivate innovative designs in both mechanical and civil engineered equipment.

Cloning and Characterization of a Novel Endo-Type Metal-Independent Alginate Lyase from the Marine Bacteria Vibrio sp. Ni1.

The applications of alginate lyase are diverse, but efficient commercial enzymes are still unavailable. In this study, a novel alginate lyase with high activity was obtained from the marine bacteria Vibrio sp. Ni1. The ORF of the algB gene has 1824 bp, encoding 607 amino acids. Homology analysis shows that AlgB belongs to the PL7 family. There are two catalytic domains with the typical region of QIH found in AlgB. The purified recombinant enzyme of AlgB shows highest activity at 35 °C, pH 8.0, and 50 mmol/L Tris-HCl without any metal ions. Only K+ slightly enhances the activity, while Fe2+ and Cu2+ strongly inhibit the activity. The AlgB preferred polyM as substrate. The end products of enzymatic mixture are DP2 and DP3, without any metal ion to assist them. This enzyme has good industrial application prospects.

Targets and Potential Mechanism of Scutellaria baicalensis in Treatment of Primary Hepatocellular Carcinoma Based on Bioinformatics Analysis.

OBJECTIVE: To analyze the target and potential mechanism of Scutellaria baicalensis (SB) in the treatment of HCC based on bioinformatics, so as to provide suggestions for the diagnosis, treatment, and drug development of hepatocellular carcinoma (HCC). METHODS: The regulated gene targets of SB were screened by gene expression pattern clustering and differential analysis of gene expression data of HepG2 cells treated with SB at 0 h, 1 h, 3 h, 6 h, 12 h, and 24 h. The module genes related to HCC were identified by the weighted gene coexpression network analysis (WGCNA). KEGG and GO enrichment were used to analyze the molecular function and structure of the module, and GSEA was used to evaluate the different functional pathways between normal people and patients with HCC. Then, the module gene was used for univariate Cox proportional hazard analysis and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis to build a prognostic model. The protein-protein interaction network (PPI) was used to analyze the core genes regulated by SB (CGRSB) of the module, and the survival curve revealed the CGRSB impact on patient survival. The CIBERSORT algorithm combined with correlation analysis to explore the relationship between CGRSB and immune infiltration. Finally, the single-cell sequencing technique was used to analyze the distribution of CGRSB at the cellular level. RESULTS: SB could regulate 903 genes, of which 234 were related to the occurrence of HCC. The prognosis model constructed by these genes has a good effect in evaluating the survival of patients. KEGG and GO enrichment analysis showed that the regulation of SB on HCC mainly focused on some cell proliferation, apoptosis, and immune-related functions. GSEA enrichment analysis showed that these functions are related to the occurrence of HCC. A total of 24 CGRSB were obtained after screening, of which 13 were significantly related to survival, and most of them were unfavorable factors for patient survival. The correlation analysis of gene expression showed that most of CGRSB was significantly correlated with T cells, macrophages, and other functions. The results of single-cell analysis showed that the distribution of CGRSB in macrophages was the most. CONCLUSION: SB has high credibility in the treatment of HCC, such as CDK2, AURKB, RRM2, CENPE, ESR1, and PRIM2. These targets can be used as potential biomarkers for clinical diagnosis. The research also shows that the p53 signal pathway, MAPK signal pathway, apoptosis pathway, T cell receptor pathway, and macrophage-mediated tumor immunity play the most important role in the mechanism of SB in treating HCC.

Structural insights revealed by crystal structures of CYP76AH1 and CYP76AH1 in complex with its natural substrate.

CYP76AH1 is the key enzyme in the biosynthesis pathway of tanshinones in Salvia miltiorrhiza, which are famous natural products with activities against various heart diseases and others. CYP76AH1 is a membrane-associated typical plant class II cytochrome P450 enzyme and its catalytic mechanism has not to be clearly elucidated. Structural determination of eukaryotic P450 enzymes is extremely challenging. Recently, we solved the crystal structures of CYP76AH1 and CYP76AH1 in complex with its natural substrate miltiradiene. The structure of CYP76AH1 complexed with miltiradiene is the first plant cytochrome P450 structure in complex with natural substrate. The studies revealed a unique array pattern of amino acid residues, which may play an important role in orienting and stabilizing the substrate for catalysis. This work would provide structural insights into CYP76AH1 and related P450s and the basis to efficiently improve tanshinone production by synthetic biology techniques.

Increased expression of cyclooxygenase-2 in synovium tissues and synovial fluid from patients with knee osteoarthritis is associated with downregulated microRNA-758-3p expression.

Cyclooxygenase-2 (COX-2) is a common factor in inflammation, and its specific regulatory mechanism has not been fully elucidated. The present study aimed to investigate COX-2 mRNA and protein expression levels in synovium tissues and synovial fluid from patients with knee osteoarthritis (KOA), and determine the molecular mechanism by which microRNA (miRNA/miR)-758 regulates KOA via COX-2. A total of 37 patients with KOA and 29 patients with acute knee trauma (control group) were enrolled in the present study. Reverse transcription-quantitative PCR analysis was performed to detect miR-758-3p and COX-2 mRNA expression, while western blotting and ELISA were performed to detect COX-2 protein expression in synovium and synovial fluid, respectively. The dual-luciferase reporter assay was performed to verify the interaction between miR-758-3p and the 3'-untraslated region (UTR) of COX-2 mRNA. Synovial cells were transfected with agomiR-758-3p, and the MTT assay was performed to assess cell proliferation. The results demonstrated that COX-2 expression was higher in patients with KOA than those with acute knee trauma. Conversely, miR-758-3p expression was lower in patients with KOA than those with acute knee trauma. Notably, miR-758-3p interacted with the 3'-UTR of COX-2 mRNA to regulate its expression. Overexpression of miR-758-3p inhibited the expression and release of COX-2, as well as the proliferation of human KOA synovial cells. Taken together, these results suggest that COX-2 expression is upregulated in synovium tissues and synovial fluid from patients with KOA, which is associated with downregulated miR-758-3p expression. In addition, miR-758-3p affects the proliferation of synovial cells and the expression of relevant proteins in these cells, thus promoting the occurrence and development of KOA.

CaCO3-Chitosan Composites Granules for Instant Hemostasis and Wound Healing.

Excessive bleeding induces a high risk of death and is a leading cause of deaths that result from traffic accidents and military conflict. In this paper, we developed a novel porous chitosan-CaCO3 (CS-CaCO3) composite material and investigated its hemostatic properties and wound healing performance. The CS-CaCO3 composites material was prepared via a wet-granulation method. Granulation increases the infiltrating ability of the CS-CaCO3 composites material. The improved water absorption ability was enhanced to 460% for the CS-CaCO3 composites material compared to the CaCO3 or chitosan with only one single component. The coagulation studies in vivo illustrated that the blood clotting time was greatly reduced from 31 s for CaCO3 to 16 s for the CS-CaCO3 composite material. According to the results of the wound healing experiments in rats, it was found that the CS-CaCO3 composite material can promote wound healing. The CS-CaCO3 composite material could accelerate wound healing to a rate of 9 days, compared with 12 days for the CaCO3. The hemostatic activity, biocompatibility, and low cost of CS-CaCO3 composite material make it a potential agent for effective hemostatic and wound healing materials.

Growth of Au nanoparticles on phosphorylated zein protein particles for use as biomimetic catalysts for cascade reactions at the oil-water interface.

Chemo-enzymatic cascade processes are invaluable due to their ability to rapidly construct high-value products from available feedstock chemicals in a one-pot relay manner. However, they have proven to be challenging because of the mutual inactivation of both catalysts. A conceptually novel strategy based on Pickering interfacial catalysis (PIC) is proposed here to address this challenge. This study aimed to construct a protein-stabilized Pickering system for biphasic cascade catalysis, enabled by phosphorylated zein nanoparticles (ZCPOPs) immobilized in gold nanoparticles (Au NCs). Ultra-small Au NCs, 1-2 nm in diameter, were integrated into ZCPOPs at room temperature. Then, the as-synthesized ZCPOPs-Au NCs were used to stabilize the oil-in-water (o/w) Pickering emulsion. Besides their excellent catalytic activity and recycling ability in a variety of oil phases, ZCPOPs-Au NCs possess unpredictable catalytic activity and exhibit mimicking properties of horseradish peroxidase. Particularly, the cascade reaction is well achieved using a metal catalyst and a biocatalyst at the oil-water interface. The result showed that such a combination of chemo- and biocatalysis improved the catalytic yield more than two times compared with that of sole metal catalysis. This study opened a new avenue to design nanomaterials using the combination of chemo- and biocatalysis in a Pickering emulsion system for multistep syntheses.

Bioavailability of quercetin in zein-based colloidal particles-stabilized Pickering emulsions investigated by the in vitro digestion coupled with Caco-2 cell monolayer model.

Protein-based Pickering emulsions have received considerable attention as nutraceutical vehicles. However, the oral bioavailability of nutraceuticals encapsulated in Pickering emulsions was not well established. In this work, a simulated gastrointestinal tract/Caco-2 cell culture model was applied to investigate the oral bioavailability of quercetin encapsulated in zein-based Pickering emulsions with quercetin in zein particles as the control. Pickering emulsions with shell (ZCP-QE) and core quercetin (ZCPE-Q) were constructed, and quercetin bioaccessibility, cell uptake and secretion, and the overall bioavailability were evaluated and compared. The overall oral bioavailability of quercetin was increased from 2.71% (bulk oil) to 38.18% (ZCPs-Q) and 18.97% (ZCPE-Q), particularly reached 41.22% for ZCP-QE. This work took new insights into the contributions of bioaccessibility and absorption (cell uptake plus secretion) to the overall oral bioavailability of quercetin. A schematic representation is proposed to relate the types of colloidal nanostructures in the digesta to the uptake, cell absorption, and overall oral bioavailability of quercetin. This study provided an attractive basis for identifying effective strategies to improve the oral bioavailability of hydrophobic nutraceuticals.

Shape Memory Alloy (SMA) Actuator With Embedded Liquid Metal Curvature Sensor for Closed-Loop Control.

We introduce a soft robot actuator composed of a pre-stressed elastomer film embedded with shape memory alloy (SMA) and a liquid metal (LM) curvature sensor. SMA-based actuators are commonly used as electrically-powered limbs to enable walking, crawling, and swimming of soft robots. However, they are susceptible to overheating and long-term degradation if they are electrically stimulated before they have time to mechanically recover from their previous activation cycle. Here, we address this by embedding the soft actuator with a capacitive LM sensor capable of measuring bending curvature. The soft sensor is thin and elastic and can track curvature changes without significantly altering the natural mechanical properties of the soft actuator. We show that the sensor can be incorporated into a closed-loop "bang-bang" controller to ensure that the actuator fully relaxes to its natural curvature before the next activation cycle. In this way, the activation frequency of the actuator can be dynamically adapted for continuous, cyclic actuation. Moreover, in the special case of slower, low power actuation, we can use the embedded curvature sensor as feedback for achieving partial actuation and limiting the amount of curvature change.