Preparation and characterisation of novel casein-gum Arabic composite microcapsules for targeted in vivo delivery of Lactiplantibacillus plantarum A3

The health benefits of probiotics in the body are predicated on their ability to remain viable in harsh gastrointestinal conditions and complex pathological microenvironments. Casein and gum Arabic (GA), with dual emulsifying and stabilising effects in colloidal systems. Therefore, the objective of this research was to develop a novel microcapsule to encapsulate Lactiplantibacillus plantarum A3 using casein and GA as wall materials to improve the survival of the bacteria during gastrointestinal digestion, storage and lyophilization. The casein and GA composite microcapsules were prepared and characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the microcapsules had stable morphology, uniform size and spherical shape. The results revealed that the encapsulation of microcapsules significantly improved the survival of L. plantarum A3 in gastrointestinal fluid environment (5.52 × 109 cfu/ml) and lyophilization treatment (6.25 × 109 cfu/ml). Furthermore, the microencapsulated L. plantarum A3 exhibited an improved ability to regulate intestinal microbiota by effectively increasing the relative abundance of Bacteroidetes, Proteobacteria and Actinobacteria and decreasing the relative abundance of Firmicutes in vivo. The findings of the study will help to design a lactic acid bacteria encapsulation system based on the gastrointestinal environment and provide a basis for the development of probiotic functional products.

Crystal dissolution by particle detachment

Crystal dissolution, which is a fundamental process in both natural and technological settings, has been predominately viewed as a process of ion-by-ion detachment into a surrounding solvent. Here we report a mechanism of dissolution by particle detachment (DPD) that dominates in mesocrystals formed via crystallization by particle attachment (CPA). Using liquid phase electron microscopy to directly observe dissolution of hematite crystals - both compact rhombohedra and mesocrystals of coaligned nanoparticles - we find that the mesocrystals evolve into branched structures, which disintegrate as individual sub-particles detach. The resulting dissolution rates far exceed those for equivalent masses of compact single crystals. Applying a numerical generalization of the Gibbs-Thomson effect, we show that the physical drivers of DPD are curvature and strain inherently tied to the original CPA process. Based on the generality of the model, we anticipate that DPD is widespread for both natural minerals and synthetic crystals formed via CPA.

Facet-Dependent Photodegradation of Methylene Blue by Hematite Nanoplates in Visible Light

The expression of specific crystal facets in different nanostructures is known to play a vital role in determining the sensitivity toward the photodegradation of organics, which can generally be ascribed to differences in surface structure and energy. Herein, we report the synthesis of hematite nanoplates with controlled relative exposure of basal (001) and edge (012) facets, enabling us to establish direct correlation between the surface structure and the photocatalytic degradation efficiency of methylene blue (MB) in the presence of hydrogen peroxide. MB adsorption experiments showed that the capacity on (001) is about three times larger than on (012). Density functional theory calculations suggest the adsorption energy on the (001) surface is 6.28 kcal/mol lower than that on the (012) surface. However, the MB photodegradation rate on the (001) surface is around 14.5 times faster than on the (012) surface. We attribute this to a higher availability of the photoelectron accepting surface Fe³⁺ sites on the (001) facet. This facilitates more efficient iron valence cycling and the heterogeneous photo-Fenton reaction yielding MB-oxidizing hydroxyl radicals at the surface. Our findings help establish a rational basis for the design and optimization of hematite nanostructures as photocatalysts for environmental remediation.

Connecting particle interactions to agglomerate morphology and rheology of boehmite nanocrystal suspensions

HYPOTHESIS

The rheology of complex suspensions, such as nuclear waste slurries at the Hanford and Savannah River sites, imposes significant challenges on industrial-scale processing. Investigating the rheology and connecting it to the agglomerate morphology and underlying particle interactions in slurries will provide important fundamental knowledge, as well as prescriptive data for practical applications. Here, we use suspensions of nano-scale aluminum oxyhydroxide minerals in the form of boehmite as an analog of the radioactive waste slurry to investigate the correlation between particle interactions, agglomerate morphology, and slurry rheology.

EXPERIMENTS

A combination of Couette rheometry and small-angle scattering techniques (independently and simultaneously) were used to understand how agglomerate structure of slurry changes under flow and how these structural changes manifest themselves in the bulk rheology of the suspensions.

FINDINGS

Our experiments show that the boehmite slurries are thixotropic, with the rheology and structure of the suspensions changing with increasing exposure to flow. In the slurries, particle agglomerates begin as loose, system-spanning clusters, but exposure to moderate shear rates causes the agglomerates to irreversibly consolidate into denser clusters of finite size. The structural changes directly influence the rheological properties of the slurries such as viscosity and viscoelasticity. Our study shows that solution pH affects the amount of structural rearrangement and the kinetics of the rearrangement process, with an increase in pH leading to faster and more dramatic changes in bulk rheology, which can be understood via correlations between particle interactions and the strength of particle network. Nearly identical structural changes were also observed in Poiseuille flow geometries, implying that the observed changes are relevant in pipe flow as well.

Cr(III) Adsorption by Cluster Formation on Boehmite Nanoplates in Highly Alkaline Solution

The development of advanced functional nanomaterials for selective adsorption in complex chemical environments requires partner studies of binding mechanisms. Motivated by observations of selective Cr(III) adsorption on boehmite nanoplates (γ-AlOOH) in highly caustic multicomponent solutions of nuclear tank waste, here we unravel the adsorption mechanism in molecular detail. We examined Cr(III) adsorption to synthetic boehmite nanoplates in sodium hydroxide solutions up to 3 M, using a combination of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), scanning/transmission electron microscopy (S/TEM), electron energy loss spectroscopy (EELS), high-resolution atomic force microscopy (HR-AFM), time-of-fight secondary ion mass spectrometry (ToF-SIMS), Cr K-edge X-ray absorption near edge structure (XANES)/extended X-ray absorption fine structure (EXAFS), and electron paramagnetic resonance (EPR). Adsorption isotherms and kinetics were successfully fit to Langmuir and pseudo-second-order kinetic models, respectively, consistent with monotonic uptake of Cr(OH)₄^- monomers until saturation coverage of approximately half the aluminum surface site density. High resolution AFM revealed monolayer cluster self-assembly on the (010) basal surfaces with increasing Cr(III) loading, possessing a structural motif similar to guyanaite (β-CrOOH), stabilized by corner-sharing Cr-O-Cr bonds and attached to the surface with edge-sharing Cr-O-Al bonds. The selective uptake appears related to short-range surface templating effects, with bridging metal connections likely enabled by hydroxyl anion ligand exchange reactions at the surface. Such a cluster formation mechanism, which stops short of more laterally extensive heteroepitaxy, could be a metal uptake discrimination mechanism more prevalent than currently recognized.

Facet-Specific Photocatalytic Degradation of Organics by Heterogeneous Fenton Chemistry on Hematite Nanoparticles

Hematite nanoparticles are abundant in the photic zone of aquatic environments, where they play a prominent role in photocatalytic transformations of bound organics. Here, we examine the photocatalytic degradation of rhodamine B by visible light using two different structurally well-defined hematite nanoparticle morphologies. In addition to detailed solid characterization and aqueous kinetics measurements, we also exploit species-selective scavengers in electron paramagnetic resonance spectroscopy to sequester specific reaction channels and thereby assess their impact. The photodegradation rates for nanoplates dominated by {001} facets and nanocubes dominated by {012} facets were 0.13 and 0.7 h^-1, respectively, and the turnover frequencies for the active sites on {001} and {012} were 7.89 × 10^-3 and 3.07× 10^-3 s^-1, yielding apparent activation energies of 17.13 and 24.94 kcal/mol within the energetic span model, respectively. Facet-specific differences appear to be directly not linked with the simple aerial cation site density but instead with their extent of undercoordination. By establishing this linkage, the findings lay a foundation for predicting the photocatalytic degradation efficiency for the myriad of possible hematite nanoparticle morphologies and more broadly help unveil key reactions at the interface that may govern photocatalytic organic transformations in natural and engineered aquatic environments.

Differentiation between malignant and benign breast masses: combination of semi-quantitative analysis on DCE-MRI and histogram analysis of ADC maps

AIM

To investigate the performance of combined semi-quantitative analysis on dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) and histogram analysis of diffusion-weighted imaging (DWI) for distinguishing malignant from benign breast masses.

MATERIALS AND METHODS

This study included 178 patients with breast masses (benign:malignant=88:9) who underwent both DCE-MRI and DWI. The semi-quantitative parameters, derived from DCE-MRI, included maximum slope of increase (MSI), signal intensity slope (SI_slope), initial percentage of enhancement (E_initial), percentage of peak enhancement (E_peak), early signal enhancement ratio (ESER), and second enhancement percentage (SEP). Histogram parameters derived from apparent diffusion coefficient (ADC) maps included ADC_min, ADC_max, ADC_mean, ADC₁₀, ADC₂₅, ADC₅₀, ADC₇₅, ADC₉₀, skewness, and kurtosis. All parameters were compared between malignant and benign groups, and their differences were tested using independent-samples t-test or Mann-Whitney test. Receiver operating characteristic (ROC) curves were used to determine the diagnostic value of each significant parameter.

RESULTS

Among semi-quantitative parameters, SI_slope exhibited the best diagnostic performance in predicting malignancy (cut-off value, 0.096; ROC, 0.756; sensitivity, 86.7%; specificity, 61.4%). Among histogram parameters, ADC₁₀ exhibited the best diagnostic performance in predicting malignancy (cut-off value, 1.051; ROC, 0.885; sensitivity, 86.7%; specificity, 84.1%). The optimal diagnostic performance of combined ADC₁₀ and SI_slope (area under curve [AUC], 0.888; sensitivity, 82.2%; specificity, 95.5%) was significantly better than SI_slope alone (p<0.001). Moreover, the combination showed higher AUC (0.888 versus 0.885) than ADC₁₀ alone, but the difference was not statistically significant (p=0.914).

CONCLUSION

SI_slope and ADC₁₀ are significant predictors for breast malignancy. The combination of DCE-MRI and DWI improves differentiating performance.

Citrullinated vimentin stimulates proliferation, pro-inflammatory cytokine secretion, and PADI4 and RANKL expression of fibroblast-like synoviocytes in rheumatoid arthritis

OBJECTIVES

We aimed to investigate the possible effects of vimentin (Vim) and citrullinated Vim (cVim) on proliferation capacity, pro-inflammatory cytokine secretion, and the expression of peptidylarginine deiminase type 4 (PADI4) and receptor activator of nuclear factor kappa B ligand (RANKL) in cultured fibroblast-like synoviocytes (FLSs) from rheumatoid arthritis (RA) and osteoarthritis (OA) patients.

METHOD

Human native Vim was citrullinated with rabbit PAD in vitro and detected using a Western blot assay with anti-modified citrulline antibody (anti-MC Ab). FLSs from RA or OA synovial samples were stimulated with Vim or cVim. Cell proliferation capacity was determined using the Celltiter 96 AQueous cell proliferation assay. The concentrations of tumour necrosis factor (TNF)-α, interleukin (IL)-1, and IL-17 were measured by enzyme-linked immunosorbent assay (ELISA). The expression of PADI4 and RANKL was measured by real-time polymerase chain reaction (RT-PCR) and a Western blot assay.

RESULTS

Our Western blot assay with anti-MC Ab indicated that the amount of cVim increased significantly after Vim had been incubated with rabbit PAD in vitro. The proliferation capacity and secretion of TNF-α and IL-1 were significantly enhanced in the FLSs of RA patients when treated with cVim. However, when treated with Vim, an inhibitory effect on the proliferation capacity was noted in the FLSs from RA and also from OA patients. cVim significantly increased the expression of PADI4 and RANKL in the FLSs from RA patients.

CONCLUSION

cVim seems to have remarkable biological effects on RA as confirmed by the stimulation of proliferation capacity, pro-inflammatory cytokine secretion, and PADI4 and RANKL expression in the FLSs of RA patients.

Comparative proteomic analysis for the detection of biomarkers in pancreatic ductal adenocarcinomas

AIMS

To search for novel potential protein biomarkers for the early detection and better intervention of pancreatic ductal adenocarcinoma (PDAC).

METHODS

Eight pairs of matched PDAC and non-cancerous pancreas tissues were profiled with two-dimensional electrophoresis; differentially expressed proteins were identified by mass spectrometry. Expression patterns of TBX4 (T-box transcription factor TBX4) and HSP60 (60 KDa heat shock protein) were studied with immunohistochemistry using tissue microarrays.

RESULTS

A total of 48 differentially expressed proteins were identified; 30 of them are novel potential biomarkers. Immunohistochemistry showed that TBX4 expression could be seen in both centroacinar cells and small ducts in normal pancreas and tumour cells in 5/5 (100%) well differentiated, 35/38 (92.1%) moderately differentiated, and 11/18 (61.1%) poorly differentiated PDAC tissues with different staining intensity. However, in normal acinar cells and tumour cells in the other 3/38 (7.9%) moderately differentiated and 7/18 (38.9%) poorly differentiated PDAC tissues, there was no visible TBX4 expression. The expression difference of TBX4 between moderately differentiated and poorly differentiated PDAC tissues was statistically significant (p<0.01). In addition, there was obvious morphology difference between TBX4 negatively stained and positively stained tumour cells, which suggests different cellular origins. Strong expression of HSP60 could be seen in both acinar cells and small ducts in normal pancreas tissues and tumour cells in PDAC tissues except for islets and tumour stoma; no correlation was found between HSP60 expression and differentiation of PDAC tissues.

CONCLUSIONS

30 novel potential biomarkers differentially expressed in PDAC tissues were identified. TBX4 may be a differentiation related protein; its prognostic value for PDAC deserves further study.