Gel Filtration Research Articles

Extraction and functional characterization of fucoidans and alginates from Ecklonia maxima: A focus on skin, immune, and intestinal health

Polysaccharides from the brown seaweed Ecklonia maxima (EM), were structurally characterized using high performance size exclusion chromatography (HPSEC), Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy, and assessed for immunomodulation. MTT and AlamarBlue assays evaluated their effects on cell viability and proliferation (skin cells; HDF, HaCaT). Nitric oxide (NO) production and phagocytosis activities were evaluated using RAW264.7 cells. In addition, Caco-2 cells were exposed to EM polysaccharides, including fucoidans and alginates, with the aim of evaluating their potential toxicity towards intestinal cells. The expression levels of tumor necrosis factor alpha (TNF-α) and transforming growth factor beta (TGF-β1) were measured by qPCR at 24 h after treatment with fucoidans (EM-1A, EM-1B, EM-2B, EM-3B) and alginates (EM-2A, EM-3A) polysaccharide fractions, demonstrating that EM-2A and 3A effectively inhibited inflammation, while EM-2B increased wound healing in HaCaT. Skin cell proliferation and migration were significantly increased (0.13 μg/μL), while exposure of RAW264.7 cells to cold or hot-extracted (2A, 2B) polysaccharides did not affect cell proliferation within 24 h. Cell proliferation in Caco-2 cells were significantly reduced by EM-1A fraction at 72 h, inhibiting cell proliferation (p < 0.001). Phagocytosis activity was significantly higher in EM-2B (122.3 ± 1.2%, p < 0.0001), suggesting pro-inflammatory potential. HDF cell proliferation was higher in EM-3A, whereas SOD activity was lower than controls (LPS: 27.3 ± 1.3%). Fucoidan from fraction 2B fraction accelerated skin cell proliferation and migration, showing their potential as bioactive compounds. The findings suggest that EM fucoidan and alginate polysaccharides would be useful for the development of products for food, pharmaceutical and biotechnology applications.

Study on the Structural Features of Eight Dendrobium Polysaccharides and Their Protective Effects on Gastric Mucosa.

This study aimed to analyze the structure of polysaccharides from eight different Dendrobium species and their protective effects on gastric mucosa. Ultraviolet (UV) analysis showed that the contents of eight polysaccharides ranged from 51.89 ± 6.91% to 80.57 ± 11.63%; the degree of acetylation ranged from 0.17 ± 0.03 to 0.48 ± 0.03. High-performance liquid chromatography (HPLC) results showed that these polysaccharides were mainly composed of mannose (Man) and glucose (Glc) with a small amount of galactose (Gal) and arabinose (Ara), and the monosaccharide ratios of different Dendrobium species were different. High-performance size exclusion chromatography-multi angle light scattering-refractive index detector (HPSEC-MALS-RID) showed that the molecular weight (Mw) of all Dendrobium polysaccharides was >1 × 105 Da; D. huoshanense had the lowest molecular weight. Subsequently, an ethanol injured GES-1 cell model was constructed to evaluate the gastric mucosal protective potential of polysaccharides from eight different Dendrobium species. The results showed that the protective effect of the low concentration 50 μg/mL DHP treatment group was similar to that of the control group (p > 0.05), and the cell viability could reach 97.32% of that of the control group. Based on the polysaccharide composition, different kinds of Dendrobium have different degrees of migration and repair effects on GES-1 damaged cells, and the effect of DHP is slightly better than that of other varieties (83.13 ± 1.05%). Additionally, Dendrobium polysaccharides alleviated ethanol-induced oxidative stress and inflammatory response in gastric mucosal cells by enhancing the activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase) and reducing the levels of malondialdehyde and reactive oxygen species. Overall, DHP can most effectively protect gastric mucosa. These findings enhance our understanding of the relationship between the structure and biological activity of Dendrobium polysaccharides, providing a foundation for the quality control of Dendrobium. Furthermore, these findings offer theoretical support for the development of Dendrobium polysaccharides as nutraceuticals to treat digestive system diseases.

Storage-induced changes in β-strand interactions within bovine lactoferrin powder analyzed through X-ray diffraction

Bovine lactoferrin (bLF) is a multifunctional protein used in the food and pharmaceutical industries. Various commercially available bLF powders (bLFPs) have different ratios of protein monomers to aggregates, which affects the aggregation rate. However, the changes in molecular structure and interactions during aggregation are unclear. This study investigated changes in the structure and interactions of stored bLFPs during aggregation. Five commercially available bLFPs with different molecular weight distributions were analyzed before and after storage using size-exclusion chromatography and X-ray diffraction (XRD) to monitor aggregation and β-strand interaction, respectively. These bLFPs were stored for four weeks under high temperature and humidity conditions as a stress test. The XRD results revealed changes in peak II (around 2θ = 20°), corresponding to β-strand interactions. The peak II change rate suggested that the aggregation occurs due to partial structural fluctuations and interaction changes. Furthermore, time-course analysis of peak II and correlations with the pre-storage monomer ratio and aggregation phase index demonstrated that β-strand interactions decreased during the transformation of monomers to low-molecular-weight (LMW) aggregates, while it increased during the LMW-to-high-molecular-weight aggregate phase. These results provide novel insights into the conformational changes and molecular interactions of bLFPs during aggregation.

Simultaneous and sequential combination of techniques for the sustainable and extensive extraction of proteins and polyphenols from malt rootlets

The emergence of tecnhiques such as microwave-assisted extraction (MAE), enzyme-assisted extraction (EAE), ultrasounds-assisted extraction (UAE), and pressurized liquid extraction (PLE) has brough many benefits but their single use does not guarantee the hollistic extraction of target compounds from complex samples. Taking into account their different principles and that one technique may favour the extraction of certain compounds over others, this work proposes the combination of these techniques for improving extraction yields in the recovery of proteins, as example of large molecule, and phenolic compounds, as example of small molecule, from a recalcitrant sample. No single extraction technique recovered all proteins or phenolic compounds, even after a proper optimization. Among them, PLE was the most advantageous, enabling the extraction of 67 % proteins and 1.20 g gallic acid equivalent (GAE)/100 g sample. Analysis of samples by scanning electron microscopy (SEM) and separation of extracts by reversed-phase high performance liquid chromatography (RP-HPLC) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that PLE showed the most distinct efficiency among EAE, MAE, and UAE, whereas the latter three exhibited more similar results. Based in these results, ten different combinations (sequential and/or simultaneous) of these techniques were proposed. PLE in combination with another technique showed a great potential for the extraction of both large and small molecules. Particularly, the combination of EAE and PLE recovered 100 % of proteins and more than three times the phenolic compounds extracted by other methods reported in the literature, even revealing significant synergistic effects.

Scaling laws for nanoparticles – Online shape heterogeneity analysis by size exclusion chromatography coupled with multi-angle light scattering

Nanoparticle-based drug delivery systems are rising technologies to access challenging therapeutic targets. Following commercial success of lipid-based nanoparticles (LBNP), accruing understandings of nanoparticle structures and critical quality attributes through advanced analytics are beneficial to future clinical development and generalization of this delivery platform. The morphological attributes of nanoparticles, such as shape, can affect uptake, cell-interaction, drug release, circulation, and flow. Gaining an understanding of these structure-activity relationships in early-stage formulation development is important because mix morphologies can affect quality and potency but often exist before process control strategies are fully implemented. In this study, we used shape heterogeneous nanoparticle mixtures, containing various populations of liposomes and lipodisks, as a model system and developed an online semi-quantitative method to characterize the nanoparticle shape heterogeneity by size exclusion chromatography (SEC) coupled with multi-angle light scattering (MALS). The liposomes and lipodisks were separated in SEC when their sizes were ∼3 fold different. When the particles of different shapes were in similar sizes, size-based separation was not always feasible. Instead, light scattering data distinguished liposomes and lipodisks by the scaling law linking radius of gyration and molecular weight of the nanoparticles, enabling morphological identification. A semi-quantitative model was built based on the exponential correlation between the scaling law exponents and the ratios of liposomes and lipodisks. The model was applied to test 6 random formulations made with different compositions and manufacturing processes, and the predicted liposome percentage for 5 formulations was within 25 % absolute difference from the percentage determined by cryogenic electron microscopy (cryo-EM). We envision this method being routinely used to characterize liposome and lipodisk shape heterogeneity during formulation screening as well as on stability studies. Potentially, the method can be converted to in-process control method and extended to other categories of nanoparticles beyond liposomes.

Novel peptides with calcium‐binding capacity from antler bone hydrolysate, its bioactivity on MC3T3‐E1 cells, and the possible chelating mode

AbstractIn this study, peptide‐calcium chelate was screened from antler bone hydrolysate, and its bioactivity on MC3T3‐E1 cells and its chelating mechanism were investigated. In vitro experiments showed that peptide‐calcium chelate promoted the differentiation and mineralization of MC3T3‐E1 cells. Subsequently, three novel calcium‐chelating peptides were obtained from antler bone hydrolysate using hydroxyapatite chromatography (HAC), Sephadex G‐25 gel filtration chromatography, and reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Meanwhile, this work determined peptides' amino acid sequences as TKLGTQLQL, LETVILGLLKT, and KMVFLMDLLK based on LC–MS/MS. Then the present work prepared the three peptides, with the corresponding calcium‐chelating rates being verified as 87.68 ± 2.86%, 80.72 ± 0.93%, and 67.96 ± 0.98%, respectively. Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible absorption (UV–vis) spectroscopy, X‐ray diffraction (XRD), circular dichroism (CD), zeta potential, and molecular dynamics (MD) simulations were adopted to investigate the chelating mode of peptides with calcium ions. As a result, oxygen in the carboxyl group and the nitrogen in the amino group were related to calcium binding. In addition, the chelation site preferred the negatively charged carboxylate groups of Leu or Thr. The present work revealed that antler bone might be the new calcium‐chelating peptide source and elucidated their positive role in osteogenesis.

Characterization of Peptide Profiles and the Hypoallergenic and High Antioxidant Activity of Whey Protein Hydrolysate Prepared Using Different Hydrolysis Modes.

Food proteins and peptides are generally considered a source of dietary antioxidants. The aim of this study was to investigate the antioxidant activity, allergenicity, and peptide profiles of whey protein hydrolysates (WPHs) using different hydrolysis methods. The results demonstrated that the degrees of hydrolysis of the hydrolysates with one-step (O-AD) and two-step (T-AD) methods reached 16.25% and 17.64%, respectively. The size exclusion chromatography results showed that the O-AD had a higher content of >5 and <0.3 kDa, and the distribution of peptide profiles for the two hydrolysates was significantly different. Furthermore, 5 bioactive peptides and 15 allergenic peptides were identified using peptidomics. The peptide profiles and the composition of the master proteins of the O-AD and T-AD were different. The DPPH and ABTS radical scavenging abilities of WPHs were measured, and hydrolysates were found to exhibit a strong radical scavenging ability after being treated using different hydrolysis methods. An enzyme-linked immunosorbent assay showed that the sensitization of WPHs was significantly reduced. This study may provide useful information regarding the antioxidant properties and allergenicity of WPHs.

High glucose induces DNA methyltransferase 1 dependent epigenetic reprogramming of the endothelial exosome proteome in type 2 diabetes

In response to hyperglycemia, endothelial cells (ECs) release exosomes with altered protein content and contribute to paracrine signalling, subsequently leading to vascular dysfunction in type 2 diabetes (T2D). High glucose reprograms DNA methylation patterns in various cell/tissue types, including ECs, resulting in pathologically relevant changes in cellular and extracellular proteome. However, DNA methylation-based proteome reprogramming in endothelial exosomes and associated pathological implications in T2D are not known. Hence, in the present study, we used Human umbilical vein endothelial cells (HUVECs), High Fat Diet (HFD) induced diabetic mice (C57BL/6) and clinical models to understand epigenetic basis of exosome proteome regulation in T2D pathogenesis . Exosomes were isolated by size exclusion chromatography and subjected to tandem mass tag (TMT) labelled quantitative proteomics and bioinformatics analysis. Immunoblotting was performed to validate exosome protein signature in clinically characterized individuals with T2D. We observed ECs cultured in high glucose and aortic ECs from HFD mouse expressed elevated DNA methyltransferase1 (DNMT1) levels. Quantitative proteomics of exosomes isolated from ECs treated with high glucose and overexpressing DNMT1 showed significant alterations in both protein levels and post translational modifications which were aligned to T2D associated vascular functions. Based on ontology and gene-function-disease interaction analysis, differentially expressed exosome proteins such as Thrombospondin1, Pentraxin3 and Cystatin C related to vascular complications were significantly increased in HUVECs treated with high glucose and HFD animals and T2D individuals with higher levels of glycated hemoglobin. These proteins were reduced upon treatment with 5-Aza-2’-deoxycytidine. Our study shows epigenetic regulation of exosome proteome in T2D associated vascular complications.

Beta cell extracellular vesicle PD-L1 as a novel regulator of CD8+ T cell activity and biomarker during the evolution of Type 1 Diabetes.

Surviving beta cells in type 1 diabetes respond to inflammation by upregulating programmed death-ligand 1 (PD-L1) to engage immune cell programmed death-1 (PD-1) and limit destruction by self-reactive immune cells. Extracellular vesicles (EVs) and their cargo can serve as biomarkers of beta cell health and contribute to islet intercellular communication. We hypothesized that the inflammatory milieu of type 1 diabetes increases PD-L1 in beta cell EV cargo and that EV PD-L1 may protect beta cells against immune-mediated cell death. Beta cell lines and human islets were treated with proinflammatory cytokines to model the proinflammatory type 1 diabetes microenvironment. EVs were isolated using ultracentrifugation or size exclusion chromatography and analysed via immunoblot, flow cytometry, and ELISA. EV PD-L1: PD-1 binding was assessed using a competitive binding assay and in vitro functional assays testing the ability of EV PD-L1 to inhibit NOD CD8 T cells. Plasma EV and soluble PD-L1 were assayed in plasma of individuals with islet autoantibody positivity (Ab+) or recent-onset type 1 diabetes and compared to non-diabetic controls. PD-L1 protein colocalized with tetraspanin-associated proteins intracellularly and was detected on the surface of beta cell EVs. 24-h IFN-α or IFN-γ treatment induced a two-fold increase in EV PD-L1 cargo without a corresponding increase in number of EVs. IFN exposure predominantly increased PD-L1 expression on the surface of beta cell EVs and beta cell EV PD-L1 showed a dose-dependent capacity to bind PD-1. Functional experiments demonstrated specific effects of beta cell EV PD-L1 to suppress proliferation and cytotoxicity of murine CD8 T cells. Plasma EV PD-L1 levels were increased in islet Ab+ individuals, particularly in those with single Ab+, Additionally, in from individuals with either Ab+ or type 1 diabetes, but not in controls, plasma EV PD-L1 positively correlated with circulating C-peptide, suggesting that higher EV-PD-L1 could be protective for residual beta cell function. IFN exposure increases PD-L1 on the beta cell EV surface. Beta cell EV PD-L1 binds PD1 and inhibits CD8 T cell proliferation and cytotoxicity. Circulating EV PD-L1 is higher in islet autoantibody positive patients compared to controls. Circulating EV PD-L1 levels correlate with residual C-peptide at different stages in type 1 diabetes progression. These findings suggest that EV PD-L1 could contribute to heterogeneity in type 1 diabetes progression and residual beta cell function and raise the possibility that EV PD-L1 could be exploited as a means to inhibit immune-mediated beta cell death.

Large-scale map of RNA-binding protein interactomes across the mRNA life cycle

mRNAs interact with RNA-binding proteins (RBPs) throughout their processing and maturation. While efforts have assigned RBPs to RNA substrates, less exploration has leveraged protein-protein interactions (PPIs) to study proteins in mRNA life-cycle stages. We generated an RNA-aware, RBP-centric PPI map across the mRNA life cycle in human cells by immunopurification-mass spectrometry (IP-MS) of ∼100 endogenous RBPs with and without RNase, augmented by size exclusion chromatography-mass spectrometry (SEC-MS). We identify 8,742 known and 20,802 unreported interactions between 1,125 proteins and determine that 73% of the IP-MS-identified interactions are RNA regulated. Our interactome links many proteins, some with unknown functions, to specific mRNA life-cycle stages, with nearly half associated with multiple stages. We demonstrate the value of this resource by characterizing the splicing and export functions of enhancer of rudimentary homolog (ERH), and by showing that small nuclear ribonucleoprotein U5 subunit 200 (SNRNP200) interacts with stress granule proteins and binds cytoplasmic RNA differently during stress.

N‐heterocyclic carbene copper complexes catalyze the C1 polymerization of substituted diazomethanes

AbstractThe C1 polymerization of substituted diazomethanes, including diazoethane and 2,2,2‐trifluoromethyl diazomethane, are reported. N‐heterocyclic carbene copper complexes were employed as catalysts for the polymerization reactions and afforded the corresponding persubstituted polymers containing methyl or trifluoromethyl units along the backbones of the polymer products. The polymers were characterized using size exclusion chromatography, a variety of spectroscopic and thermal techniques, and contact angle measurements. Polymers prepared using the C1 polymerization methodology described herein are more hydrophobic than related polymers that were obtained using a standard C2 polymerization method and the fluorinated polymers were determined to be more hydrophobic than their hydrogenated analogues. The relationship between fluorine content and wettability of persubstituted polymers was quantified.

Thermoregulation Effects of Phoneutria nigriventer Isolated Toxins in Rats.

Body temperature is primarily regulated by the hypothalamus, ensuring proper metabolic function. Envenomation by Phoneutria nigriventer can cause symptoms such as hypothermia, hyperthermia, sweating, and shivering, all related to thermoregulation. This study aims to analyze and identify components of the venom that affect thermoregulation and to evaluate possible mechanisms. Rats were used for thermoregulation analysis, venom fractionation by gel filtration and reverse-phase chromatography (C18), and sequencing by Edman degradation. The venom exhibited hypothermic effects in rats, while its fractions demonstrated both hypothermic (pool II) and hyperthermic (pool III) effects. Further separations of the pools with C18 identified specific peaks responsible for these effects. However, as the peaks were further purified, their effects became less significant. Tests on U87 human glioblastoma cells showed no toxicity. Sequencing of the most active peaks revealed masses similar to those of the Tachykinin and Ctenotoxin families, both known to act on the nervous system. The study concludes that molecules derived from venom can act synergistically or antagonistically. Additionally, toxins that affect thermoregulation are poorly studied and require further characterization. These toxins could potentially serve as sources for the development of new thermoregulatory drugs.

Immunomodulatory activity of red algal galactans and their partially depolymerized derivatives in RAW264.7 macrophages

Funoran and furcellaran were isolated through a successive cascade extraction process, followed by the depolymerization of extracted polymers via an auto-hydrolysis process. The molecular weight and structural peculiarities of both native and partially depolymerized polysaccharides were investigated using size-exclusion chromatography (SEC), FTIR, and NMR spectroscopy. Immunotropic effects of the native and partially depolymerized polysaccharides were explored through various in vitro assays. Although both higher and lower molecular weight funoran exhibited anti-inflammatory activity on LPS-stimulated RAW264.7 cells by significantly downregulating iNOS and COX-2 gene expression, as well as the secretion of pro-inflammatory cytokines, native funoran performed slightly better. Conversely, higher molecular weight furcellaran remarkably activated RAW264.7 cells compared to the non-treated control by inducing inflammatory mediators and pro-inflammatory cytokines, including the anti-inflammatory cytokine IL-10. Lower molecular weight furcellaran was unable to activate the macrophages, showing a similar behavior pattern to funoran samples in LPS-treated cells. Furthermore, the TLR4/NF-κB signaling pathway appears to be modulated by sulfated polysaccharides, leading to both anti-inflammatory and immunostimulatory responses in RAW264.7 cells through blocking and activating mechanisms. These findings indicate that sulfated polysaccharides could be promising therapeutic agents, and indeed, the molecular weight of polysaccharides plays a crucial role in the immune response of RAW264.7 macrophages.

Structural characterization of the POTRA domains from A. baumannii reveals new conformations in BamA

Recent studies have demonstrated BamA, the central component of the β-barrel assembly machinery (BAM), as an important therapeutic target to combat infections caused by Acinetobacter baumannii and other Gram-negative pathogens. Homology modeling indicates BamA in A.baumannii consists of five polypeptide transport-associated (POTRA) domains and a β-barrel membrane domain. We characterized the POTRA domains of BamA from A.baumannii in solution using size-exclusion chromatography small angle X-ray scattering (SEC-SAXS) analysis and determined crystal structures in two conformational states that are drastically different than those previously observed in BamA from other bacteria, indicating that the POTRA domains are even more conformationally dynamic than has been observed previously. Molecular dynamics simulations of the POTRA domains from A.baumannii and Escherichia coli allowed us to identify key structural features that contribute to the observed novel states. Together, these studies expand on our current understanding of the conformational plasticity within BamA across differing bacterial species.

Optimizing Desolvation Conditions for Glutathione-Cross-Linked Bovine Serum Albumin Nanoparticles: Implication for Intravenous Drug Delivery.

Protein-based nanocarriers, particularly albumin nanoparticles (NPs), offer numerous advantages when compared to other nanomaterials. These carriers are characterized by biocompatibility, biodegradability, reduced immunogenicity, and decreased cytotoxicity. Moreover, proteins possess an inherent ability to target tumor cells directly or indirectly. This study aims to investigate the impact of various organic solvents on the characteristics of synthesized bovine serum albumin NPs (BSA NPs). BSA NPs were produced using methanol, acetone, ethanol, dimethylsulfoxide (DMSO), and acetonitrile through the desolvation technique to achieve particles of acceptable size. Dynamic light scattering (DLS), blood compatibility assays, polyacrylamide gel electrophoresis (PAGE), and size exclusion chromatography (SEC) were employed to elucidate the properties of the generated NPs. The cytotoxicity of BSA NPs prepared under different conditions was assessed using Michigan Cancer Foundation - Mammary Adenocarcinoma - Breast Cancer 231 cells (MDA-MB-231 cells). The particle size of the synthesized NPs varied based on the organic solvent utilized, with the smallest size of 114.2 nm observed with methanol. Blood compatibility results indicated no abnormal interactions between BSA NPs and blood components. PAGE analysis revealed a strong band near 72 kDa for untreated BSA and BSA treated with all organic solvents. In SEC, the retention time of native albumin was 6.65 min, while the average retention times of the prepared BSA NPs ranged from 5.14 to 5.21 min, showing similarity to the native protein. Except for NPs produced with methanol and acetonitrile, cytotoxicity testing on MDA-MB-231 cells demonstrated no significant harmful effects at various concentrations (0-500 μg/mL). The choice of desolvating agent significantly influences the size of BSA NPs. Various factors, such as solvent characteristics like hydrogen bonds, polarity, dielectric constant, and functional groups, can affect the particle size and structure of BSA NPs. The compatibility of cross-linked BSA NPs with blood components suggests their potential for intravenous drug delivery applications.

Experimental and molecular dynamics simulation study on the mechanism of β-lactoglobulin self-aggregation induced by ultra-high temperature

Ultra-high temperature (UHT) treatment effectively prevents milk spoilage, yet it can cause protein aggregation, thereby impacting milk stability. β-Lactoglobulin (β-Lg) is a thermally unstable whey protein, but the mechanism of its self-aggregation induced by UHT treatment remains unclear. Herein, experimental approaches and molecular dynamics simulations were performed to elucidate β-Lg aggregation under UHT. The physicochemical properties of the aggregates were initially characterized after different UHT treatments. Size exclusion chromatography and multi-angle static light scattering showed β-Lg aggregates with molecular weights from 20 to 900 kDa and particle sizes from 100 to 350 nm, with bead string and irregular morphologies. Multispectroscopy showed that UHT treatment caused the unfolding of the β-Lg. Molecular dynamics simulations further observed hydrogen bond disruption and β-barrel opening, enhancing the electrostatic interactions and hydrophobicity of β-Lg surfaces, leading to non-covalent aggregation. Furthermore, SDS-PAGE confirmed the involvement of disulfide bonds in aggregate formation, and mass spectrometry identified the disruption of original disulfide bonds under UHT, promoting intermolecular disulfide bonding involving residues Cys119, Cys121, and Cys160. These findings provide a comprehensive understanding of β-Lg aggregation under UHT conditions, which is essential for improving the stability and quality of UHT-treated milk products.

Exploitation of Pore Structure for Increased CO2 Selectivity in Type 3 Porous Liquids.

CO2 capture requires materials with high adsorption selectivity and an industrial ease of implementation. To address these needs, a new class of porous materials was recently developed that combines the fluidity of solvents with the porosity of solids. Type 3 porous liquids (PLs) composed of solvents and metal-organic frameworks (MOFs) offer a promising alternative to current liquid carbon capture methods due to the inherent tunability of the nanoporous MOFs. However, the effects of MOF structural features and solvent properties on CO2-MOF interactions within PLs are not well understood. Herein experimental and computational data of CO2 gas adsorption isotherms were used to elucidate both solvent and pore structure influences on ZIF-based PLs. The roles of the pore structure including solvent size exclusion, structural environment, and MOF porosity on PL CO2 uptake were examined. A comparison of the pore structure and pore aperture was performed using ZIF-8, ZIF-L, and amorphous-ZIF-8. Adsorption experiments here have verified our previously proposed solvent size design principle for ZIF-based PLs (1.8× ZIF pore aperture). Furthermore, the CO2 adsorption isotherms of the ZIF-based PLs indicated that judicious selection of the pore environment allows for an increase in CO2 selectivity greater than expected from the individual PL components or their combination. This nonlinear increase in the CO2 selectivity is an emergent behavior resulting from the complex mixture of components specific to the ZIF-L + 2'-hydroxyacetophenone-based PL.

Generation of Anti-Epidermal Growth Factor Receptor-2 (HER2) Immunoliposomes Using Microbial Transglutaminase (mTG)-Mediated Site-Specific Conjugated Antibodies.

Nanocarriers have found their interests in many fields including drug delivery and labeling of cells with the aim to target and eradicate tumor cells. One of the approaches to specifically address nanocarriers, such as liposomes, to their target is to attach antibodies of interest to their surface. To date, the development of immunoliposomes has been widely explored but has mainly involved chemical and unspecific reactions that could impair antibody stability, integrity, and orientation, thus reducing optimized immunoliposomes generation. In this study, we report the use of the patented COVISOLINK technology and the strain-promoted alkyne-azide cycloaddition (SPAAC) to generate immunoliposomes that target HER2 positive breast cancer with Trastuzumab as the antibody to be coupled. The efficacy of our two-step functionalization strategy and the successful specific coupling of the antibodies were validated by high-performance liquid chromatography-size exclusion chromatography (HPLC-SEC), which allowed a precise quantification of antibodies conjugated to liposomes and confirmed by cryo-TEM and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses. We also demonstrate by flow cytometry and epifluorescence microscopy that the produced anti-HER2 immunoliposomes were able to interact specifically with their target cells (SK-BR-3) while remaining negative with cells that express HER2 at a low level (MDA-MB-231). Hence, for the first time, our COVISOLINK strategy using microbial transglutaminase (mTG) enables the preparation and production of well-characterized immunoliposomes that could be used in different applications, including therapies.

Phytochemical profiling and characterization of flavonoid derivatives from propolis sample and investigation of cytotoxic and antiprotozoal activities

Recently, the growth of consumer demand for functional foods with potential nutritional and health benefits led to rapid growth of analytical tools for profiling of bioactive metabolites and assure quality. Bee propolis is one of the most important bee products owing to its myriad health value. As a gummy exudate produced in beehives after harvesting from different plant species, bee propolis contains bioactive secondary metabolites. The current study aims to profiling the chemical composition of propolis samples from Nigeria using HPLC–UV-ELSD and with the aid of NMR-based analysis for assignment of metabolites classes abundant in Nigerian propolis. Red Nigerian propolis samples were subjected to phytochemical analysis using HPLC–UV-ELSD and NMR. Further chromatographic separation of promising fractions was performed by column chromatography and size exclusion chromatography. Screening of the antitrypanosomal and cytotoxic activities against Trypanosoma brucei and human leukemia cell lines (U937), respectively, was performed. The performance of LC–MS permitted identification of the different components from which 13 compound were identified and allowed combination of fractions to afford 9 fractions from which two isoflavonoids were isolated and identified using 1D and 2D NMR analysis with MS as isosativan and Medicarpin. Red Nigerian propolis crude extract showed the highest inhibitory activity at 6.5 µg/ml compared to moderate activity for the isolated compounds with MIC of 7.6 µg/ml and 12.1 µg/ml for medicarpin and isosativan, respectively. Moreover, the fraction RN-6 from the total extract showed the potent cytotoxic effect with IC50 = 26.5 µg/ml compared to standard diminazen which showed IC50 = 29.5 µg/ml.

Both Hemocyanin and β-1,3-Glucan-Binding Protein from the Shrimp Shell of Litopenaeus vannamei Are Responsible for Its Color Change from Brown to Red during Thermal Processing.

Because of the composition and structural complexity of crustacean shells, their color change mechanism during thermal processing remains unclear. This study identified and characterized two intrinsic protein components, hemocyanin (Lv-Hc) and β-1,3-glucan-binding protein (Lv-BGBP) from Litopenaeus vannamei shrimp shells by a combination of ion-exchange chromatography, gel filtration, and mass spectrometry. It was found that a mixture of Lv-Hc, a gray protein, and Lv-BGBP (which is a natural astaxanthin-binding protein with a red color) is responsible for the brown color of fresh shrimp shells. Upon heating to 100 °C, the mixture of these proteins turned red, mimicking the color change observed in cooked shrimp shells. This transition is attributed to the extremely high thermal stability of Lv-BGBP, which has the ability to protect astaxanthin from thermal induced degradation. These findings provide significant insights into the molecular mechanism governing shrimp shell coloration, advancing our understanding of crustacean biochemistry.