The fall armyworm (FAW, Spodoptera frugiperda) is an invasive lepidopteran pest of staple crops. Its broad host range, ability to spread rapidly, and increasing resistance to pesticides pose a major threat to global food security. RNA interference (RNAi) offers a sustainable and targeted alternative to broad-spectrum chemical pesticides, but its efficacy is limited in lepidopterans primarily by the rapid degradation of double-stranded RNA (dsRNA) in the midgut and poor epithelial uptake. Here, we investigated lipid nanoparticles (LNPs) as a delivery strategy to enhance dsRNA stability and uptake in FAW larvae. LNP-dsRNA complexes (40-50 nm, +39 to +56 mV) were generated by the microfluidic mixing of a ternary lipid blend. Encapsulation protected dsRNA from degradation by gut enzyme extracts for up to 1 h, even under highly alkaline conditions (pH 11.5). The analysis of larvae exposed to Cy3-labeled dsRNA by fluorescence microscopy demonstrated that LNPs improved internal distribution beyond the gut lumen, whereas unformulated dsRNA mainly accumulated at the peritrophic membrane. These results indicate that LNPs resist the gut environment and overcome limited systemic uptake, the two major physiological barriers to RNAi in lepidopterans, enabling the more efficient delivery of dsRNA. This study establishes a lipid nanoparticle-based dsRNA delivery platform that overcomes key physiological barriers in FAW, providing a prerequisite for future in vivo gene knockdown and efficacy studies.

Structural and functional integrity of the blood-brain barrier (BBB) is crucial for maintaining brain homeostasis. Preeclampsia, characterized by new-onset hypertension and endothelial dysfunction in pregnancy, often involves BBB disruption and neurological complications. Small extracellular vesicles (sEVs) have emerged as potential drivers of BBB disruption during preeclampsia; however, their impact on maternal brain health, particularly at the cellular level, remains understudied. Here, the effect of preeclampsia-derived sEVs on BBB integrity and cellular responses of brain endothelial cells, microglia and astrocytes was investigated. Circulating sEVs were isolated from plasma of healthy women and women with late-onset preeclampsia and studied in human-based mono-, bi- or tri-culture models using transwell and microfluidic (BBB-on-a-chip) systems. In these models, EV-associated signals were detected within brain endothelial cells consistent with intracellular uptake and trafficking. EV-derived cargo was detected in cells on the abluminal side of the endothelial layer, suggesting possible transfer across the barrier, although the underlying mechanism remains unclear. Exposure to preeclampsia-derived sEVs (PE-sEVs) was also associated with changes in brain endothelial cell protein composition and subcellular localization, accompanied by functional alterations of BBB properties, including increased permeability. Finally, astrocytes and microglia responded to PE-sEV exposure, as evidenced by increased IBA1 and GFAP expression, IL-6 release, and enhanced astrocyte migration. These findings suggest that circulating sEVs, including those of placental origin, may be involved in maternal brain alterations in preeclampsia potentially through effects on BBB integrity and glial activation. This may indicate the possible relevance of circulating sEVs as biomarkers and in the pathophysiology of the disease. KEY POINTS: Preeclampsia is a pregnancy-related condition involving high blood pressure and endothelial dysfunction, and is often associated with disruption of the blood-brain barrier (BBB) and neurological complications. Circulating small extracellular vesicles (sEVs) normally increase during pregnancy but are further elevated in preeclampsia, and may carry inflammatory cargo to the maternal brain. Using in vitro models, including an organ-on-a-chip, composed of human brain endothelial cells, microglia and astrocytes, this study examined how sEVs from healthy and preeclamptic pregnancies affect BBB properties, and glial activation. Results support the notion that preeclampsia-derived sEVs increase BBB permeability, traverse the endothelial layer, and induce glial responses including microglial activation and astrocyte reactivity by increased IL-6 release and cellular motility. The observed alterations may link placental dysfunction to maternal cerebrovascular injury, highlighting sEVs as potential modulators of brain damage in preeclampsia and as promising diagnostic or therapeutic targets.

Abstract The Ni(II) complex [NiCl(bda)]+ containing the aliphatic PNP pincer ligand bis((2-diphenylphosphino)ethyl)amine (bda) was covalently immobilized on the mesoporous silica SBA-15. SBA-15 was functionalized with (3-chloropropyl)triethoxysilane as an anchoring agent, which was further reacted with the amine group of the Ni-coordinated bda ligand, forming the hybrid material SBA-15@PTES@Ni. The material was characterized using Fourier-transform infrared spectroscopy, UV-visible-diffuse reflectance spectroscopy, thermogravimetric analysis, low-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and inductively coupled plasma. SBA-15@PTES@Ni was used as a catalyst for the hydrogenation of 4-nitrophenol to 4-aminophenol using NaBH4 in aqueous solution. With catalyst loadings of 1 to 3 mg, complete conversions were achieved in 6 to 10 min, with rate constants up to 6.92 × 10–3 s–1.

AbstractThe Ni(II) complex [NiCl(bda)]+ containing the aliphatic PNP pincer ligand bis((2-diphenylphosphino)ethyl)amine (bda) was covalently immobilized on the mesoporous silica SBA-15. SBA-15 was functionalized with (3-chloropropyl)triethoxysilane as an anchoring agent, which was further reacted with the amine group of the Ni-coordinated bda ligand, forming the hybrid material SBA-15@PTES@Ni. The material was characterized using Fourier-transform infrared spectroscopy, UV-visible-diffuse reflectance spectroscopy, thermogravimetric analysis, low-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and inductively coupled plasma. SBA-15@PTES@Ni was used as a catalyst for the hydrogenation of 4-nitrophenol to 4-aminophenol using NaBH4 in aqueous solution. With catalyst loadings of 1 to 3 mg, complete conversions were achieved in 6 to 10 min, with rate constants up to 6.92 × 10–3 s–1.

Abstract The control of agricultural pest insects currently relies on broad-spectrum insecticides, which select for resistance in pest populations while also harming non-target species. In contrast, RNA interference (RNAi) has a species-dependent mode of action based on the delivery of double-stranded RNA (dsRNA) that precisely matches essential genes in pests, minimizing off-target effects. The successful application of RNAi requires the development of sprayable formulations that temporarily protect the dsRNA from environmental degradation (allowing uptake by pest insects) but also ensure the efficient release of the dsRNA within insect cells. Lipid nanoparticles (LNPs) based on pharmaceutical-grade lipids are currently too expensive for agricultural use, making the development of affordable and scalable dsRNA-LNP formulations essential for spray-induced gene silencing. Here we used technical-grade lipid components (available at the ton scale) and demonstrated the cost-effective production of structurally controlled dsRNA-LNP formulations by optimizing formulation recipes and scaling up the microfluidic mixing process. The dispersions contained spherical nanoparticles less than 100 nm in diameter, with a zeta potential exceeding + 20 mV, and an entropy-driven Gibbs free energy change for dsRNA-LNP decomplexation in the moderate range of approximately – 20 kJ/mol. The formulations protected dsRNA from RNase III degradation and hydrolysis at pH 4–11 for at least 24 h while allowing SDS-mediated dsRNA release. Our work provides insight into the structure–property correlations of inexpensive dsRNA-LNP formulations for sustainable RNAi-based pest management systems.

Multicore magnetic nanoparticles (MNPs), comprising iron oxide cores embedded in a sugar or starch matrix, are a class of nanomaterials with promising magnetic heating properties. Their internal structure, and particularly the strength of the internal core-core magnetic interactions, are believed to determine the functional properties, but there have been few detailed studies on this to date. We report here on an interlaboratory and multimodality transmission electron microscopy (TEM) and magnetic study of a high-performance MNP material (supplied by Resonant Circuits Limited, RCL) that is currently being used in a clinical study for the treatment of pancreatic cancer. TEM data were collected under a variety of conditions: conventional; high-resolution; scanning; cryogenic; and, for the first time, liquid phase. All the imaging modes showed mostly irregular dextran lamellae of lateral dimensions 30-90 nm, plus ca. 15% n/n of what appeared to be 30-60 nm long "nanorods", and a multitude of well-dispersed ca. 3.7 nm diameter iron oxide cores. Cryogenic electron tomography indicated that the nanorods were edge-on lamellae, but in dried samples, tomography showed rod- or lath-shaped forms, possibly resulting from the collapse of lamellae during drying. High-resolution TEM (HRTEM) showed the dextran to be crystallized in the low-temperature hydrated dextran polymorph. Magnetic remanence Henkel-plot analysis indicated a weak core-core interaction field of ca. 4.8 kA/m. Theoretical estimates using a point-dipole model associated this field with a core-to-core separation distance of ca. 5 nm, which tallies well with the ca. 4-6 nm range of separation distances observed in liquid-cell TEM data. On this basis, we identify the structure-function link in the RCL nanoparticles to be the unusually well-dispersed multicore structure that leads to their strong heating capability. This insight provides an important design characteristic for the future development of bespoke nanomaterials for this significant clinical application.

There is a growing interest in exploring the therapeutically mediated modulation of tumor vascularization of pancreatic cancer, which is known for its poorly perfused tumor microenvironment limiting the delivery of therapeutic agents to the tumor site. Here, we assessed how magnetic hyperthermia in combination with chemotherapy selectively affects growth, the vascular compartment of tumors, and the presence of tumor cells expressing key regulators of angiogenesis. To that purpose, a orthotopic PANC-1 (fluorescent human pancreatic adenocarcinoma) mouse tumor model (Rj:Athym-Foxn1nu/nu) was used. Magnetic hyperthermia was applied alone or in combination with systemic chemotherapy (gemcitabine 50 mg per kg body weight, nab-pacitaxel 30 mg/kg body weight) on days 1 and 7 following magnetic nanoparticle application (dose: 1 mg per 100 mm3 of tumor). We used ultrasound imaging, immunohistochemistry, multi-spectral optoacoustic tomography (MSOT), and hematology to assess the biological parameters mentioned above. We found that magnetic hyperthermia in combination with gemcitabine/paclitaxel chemotherapy was able to impact tumor growth (decreased volumes and Ki67 expression) and to trigger neo-angiogenesis (increased small vessel diameter) as a result of the therapeutically mediated cell damages/stress in tumors. The applied stressors activated specific pro-angiogenic mechanisms, which differed from those seen in hypoxic conditions involving HIF-1α, since (a) treated tumors showed a significant decrease of cells expressing VEGF, CD31, HIF-1α, and neuropilin-1; and (b) the relative tumor blood volume and oxygen level remained unchanged. Neo-angiogenesis seems to be the result of the activation of cell stress pathways, like MAPK pathways (high number of pERK-expressing tumor cells). In the long term, the combination of magnetic hyperthermia and chemotherapy could potentially be applied to transiently modulate tumor angiogenesis and to improve drug accessibility during oncologic therapies of pancreatic cancer.

Lipopolysaccharide (LPS, endotoxin) is ubiquitous and represents a harmful contaminant of pharmaceutical compounds, recombinant biologicals and drug products. The pyrogen can induce severe immune responses and pathology in vitro and in vivo. Health authorities require strict control of endotoxin in parenteral drugs. However, for research and pre-clinical compound analysis, endotoxin testing is not a required quality control, which may cause potential drawbacks in the translational pipeline. Endotoxin testing is usually performed by the Limulus amebocyte lysate (LAL) assay, which is hampered by the so-called low endotoxin recovery (LER) effect when certain drug formulations are tested. A comprehensive study including structural, biophysical, and biological analyses was conducted to identify LER root cause for phosphate- and polysorbate-containing parenteral drug products. LPS in water showed extended ribbon-like aggregate structures. In placebo (formulation buffer without drug) and in drug product (drug in formulation buffer), a reaggregation of LPS into a network of interlinked micelles with hidden head group charges, and a strong reduction of the negative surface potential was observed. The non-accessibility of the LPS backbone has a direct impact leading (i) to a loss of activation of the LAL-cascade, (ii) reduced activation of the TLR4/MD-2 receptor system, and (iii) increased survival in a mouse model of endotoxemia. These data provide a structure-based explanation of the LER-underlying mechanisms. A human whole blood assay is shown to resolve LER and detect the pyrogenic activity of endotoxin with high sensitivity. This may open new test options to improve quality control in drug development and drug safety.

The effective pharmacological treatment of inflamed wounds such as pyoderma gangraenosum remains challenging, as the systemic application of suitable drugs such as glucocorticoids is compromised by severe side effects and the inherent difficulties of wounds as drug targets. Furthermore, conventional semi-solid formulations are not suitable for direct application to open wounds. Thus, the treatment of inflamed wounds could considerably benefit from the development of active wound dressings for the topical administration of anti-inflammatory drugs. Although bacterial cellulose appears to be an ideal candidate for this purpose due to its known suitability for advanced wound care and as a drug delivery system, the incorporation of poorly water-soluble compounds into the hydrophilic material still poses a problem. The use of microemulsions could solve that open issue. The present study therefore explores their use as a novel approach to incorporate poorly water-soluble glucocorticoids into bacterial cellulose. Five microemulsion formulations were loaded with hydrocortisone or dexamethasone and characterized in detail, demonstrating their regular microstructure, biocompatibility and shelf-life stability. Bacterial cellulose was successfully loaded with the formulations as confirmed by transmission electron microscopy and surprisingly showed homogenous incorporation, even of w/o type microemulsions. High and controllable drug permeation through Strat-M® membranes was observed, and the anti-inflammatory activity for permeated glucocorticoids was confirmed in vitro. This study presents a novel approach for the development of anti-inflammatory wound dressings using bacterial cellulose in combination with microemulsions.

Lipid nanoparticles (LNPs) produced by antisolvent precipitation (ASP) are used in formulations for mRNA drug delivery. The mesoscopic structure of such complex multicomponent and polydisperse nanoparticulate systems is most relevant for their drug delivery properties, medical efficiency, shelf life, and possible side effects. However, the knowledge on the structural details of such formulations is very limited. Essentially no such information is publicly available for pharmaceutical dispersions approved by numerous medicine agencies for the use in humans and loaded with mRNA encoding a mimic of the spike protein of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) as, e.g., the Comirnaty formulation (BioNTech/Pfizer). Here, we present a simple preparation method to mimic the Comirnaty drug-free LNPs including a comparison of their structural properties with those of Comirnaty. Strong evidence for the liquid state of the LNPs in both systems is found in contrast to the designation of the LNPs as solid lipid nanoparticles by BioNTech. An exceptionally detailed and reliable structural model for the LNPs i.a. revealing their unexpected narrow size distribution will be presented based on a combined small-angle X-ray scattering and photon correlation spectroscopy (SAXS/PCS) evaluation method. The results from this experimental approach are supported by light microscopy, 1H NMR spectroscopy, Raman spectroscopy, cryogenic electron microscopy (cryoTEM), and simultaneous SAXS/SANS studies. The presented results do not provide direct insights on particle formation or dispersion stability but should contribute significantly to better understanding the LNP drug delivery process, enhancing their medical benefit, and reducing side effects.

Released from trophoblast and other fetal cells, placental extracellular vesicles (EVs) reach the maternal peripheral blood and modulate immune responses. Increased EVs in plasma of preeclampsia (PE) patients indicate their involvement in the etiology of this condition. This study addresses the uptake of plasma EVs by peripheral blood mononuclear cells (PBMCs) and explores the underlying internalization mechanisms. Plasma EVs were isolated from women with normotensive pregnancy (EVNP) and those with PE (EVPE), and characterized by cryo-transmission electron microscopy, nanoparticle tracking analysis, Western blotting, flow cytometry, and micro bicinchoninic acid assay (micro-BCA). To investigate whether the origin of PBMCs affects uptake, samples from males, pregnant women, and non-pregnant women were included. Primary PBMCs and macrophages derived from the human leukemia monocytic cell line THP-1 were incubated with PKH-stained EVs, and uptake was assessed by flow cytometry and confocal microscopy. Key molecules involved in monocyte differentiation and macrophage function were evaluated in EV-treated cells using LEGENDplexTM assay and real-time polymerase chain reaction (RT-PCR). Independent of the PBMC source, EVs were mostly captured by monocytes and in a lower proportion by T lymphocytes. Capture of EVPE was higher than of EVNP in primary T lymphocytes, monocytes, and THP-1-derived macrophages. After inhibition by Wortmannin and Cytochalasin D, EV internalization by THP-1-derived macrophages was significantly inhibited but not completely abolished. No defined polarization profile of treated THP-1-derived macrophages could be identified. These findings provide evidence of EV modifications in PE, which enhance their uptake by monocytes and other immune cells, mainly through phagocytosis and endocytosis.

Membrane-shaping proteins are driving forces behind establishment of proper cell morphology and function. Yet, their reported structural and in vitro properties are noticeably inconsistent with many physiological membrane topology requirements. We demonstrate that dendritic arborization of neurons is powered by physically coordinated shaping mechanisms elicited by members of two distinct classes of membrane shapers: the F-BAR protein syndapin I and the N-Ank superfamily protein ankycorbin. Strikingly, membrane-tubulating activities by syndapin I, which would be detrimental during dendritic branching, were suppressed by ankycorbin. Ankycorbin's integration into syndapin I-decorated membrane surfaces instead promoted curvatures and topologies reflecting those observed physiologically. In line with the functional importance of this mechanism, ankycorbin- and syndapin I-mediated functions in dendritic arborization mutually depend on each other and on a surprisingly specific interface mediating complex formation of the two membrane shapers. These striking results uncovered cooperative and interdependent functions of members of two fundamentally different membrane shaper superfamilies as a previously unknown, pivotal principle in neuronal shape development.

INTRODUCTION:In orthodontics, white spot lesions are a persistent and widespread problem caused by the demineralization of buccal tooth surfaces around bonded brackets. The remaining adhesive around the brackets leads to surface roughness, which might contribute to demineralization. The present in vitro study aimed to compare a conventional and a modern adhesive system (APC Flash-Free technology) for orthodontic brackets with regard to the adhesion of Streptococcus sobrinus, a leading caries pathogen.METHODS:This in vitro study included 20 premolar teeth and compared 10 APC Flash-Free adhesive-coated ceramic brackets (FF)with 10 conventionally bonded (CB) ceramic clarity brackets. Specimens were incubated in an S. sobrinus suspension for 3 h. To evaluate the bacterial formation, samples were analysed with a scanning electron microscope (SEM). Imaging software was used to quantify and statistically compare percentage values of colonization (PVC) in both groups' adhesion and transition areas.RESULTS:We found a significant difference in biofilm formation between the groups for the adhesive and transition areas. PVC in the adhesive area was approximately 10.3-fold greater for the CB group compared with the FF group (median: 3.2 vs 0.31; P < 0.0001). For the transition area, median PVC was approximately 2.4-fold greater for the CB group compared with the FF group (median: 53.17 vs 22.11; P < 0.01).CONCLUSIONS:There was a significantly lower level of S. sobrinus formation around the FF bracket system than there was surrounding the conventionally bonded group. This study suggests that the FF adhesive bracket system can help reduce the occurrence of bacterial growth around orthodontic brackets.

IntroductionCochleates are cylindrical particles composed of dehydrated phospholipid bilayers. They are typically prepared by addition of calcium ions to vesicles composed of negatively charged phospholipids such as phosphatidylserines (PS). Due to their high physical and chemical stability, they provide an interesting alternative over other lipid-based drug formulations for example to improve oral bioavailability or to obtain a parenteral sustained-release formulation.MethodsIn the present study, the feasibility to prepare cochleate suspensions from soy lecithin-derived phosphatidylserines (SPS) was investigated and compared to the “gold standard” dioleoyl-phosphatidylserine (DOPS) cochleates. The SPS lipids covered a large range of purities between 53 and >96% and computer-controlled mixing was evaluated for the preparation of the cochleate suspensions. Electron microscopic investigations were combined with small-angle x-ray diffraction (SAXD) and Laurdan generalized polarization (GP) analysis to characterize particle structure and lipid organization.ResultsDespite some differences in particle morphology, cochleate suspensions with similar internal lipid structure as DOPS cochleates could be prepared from SPS with high headgroup purity (≥96%). Suspensions prepared from SPS with lower purity still revealed a remarkably high degree of lipid dehydration and well-organized lamellar structure. However, the particle shape was less defined, and the typical cochleate cylinders could only be detected in suspensions prepared with higher amount of calcium ions. Finally, the study proves the feasibility to prepare suspensions of cochleates or cochleate-like particles directly from a calcium salt of soy-PS by dialysis.

Objectives White spot lesions are one of the most common side effects of orthodontic therapy with a multibracket appliance and may indicate a preliminary stage of caries, also known as initial caries. Several approaches may be utilized to prevent these lesions, such as reducing bacterial adhesion in the area surrounding the bracket. This bacterial colonization can be adversely affected by a number of local characteristics. In this context, the effects of excess dental adhesive in the bracket periphery were investigated by comparing a conventional bracket system with the APC flash-free bracket system. Materials and methods Both bracket systems were applied to 24 extracted human premolars, and bacterial adhesion with Streptoccocus sobrinus ( S. sobrinus) was performed for 24 h, 48 h, 7 d, and 14 d. After incubation, bacterial colonization was examined in specific areas by electron microscopy. Results Overall, significantly fewer bacterial colonies were found in the adhesive area around the APC flash-free brackets ( n = 507 ± 13 bacteria) than the conventionally bonded bracket systems ( n = 850 ± 56 bacteria). This is a significant difference (** p = 0.004). However, APC flash-free brackets tend to create marginal gaps with more bacterial adhesion in this area than conventional bracket systems ( n = 265 ± 31 bacteria). This bacterial accumulation in the marginal-gap area is also significant (* p = 0.029). Conclusion A smooth adhesive surface with minimal adhesive excess is beneficial for reducing bacterial adhesion but also poses a risk of marginal gap formation with subsequent bacterial colonization, which can potentially trigger carious lesions. Clinical relevance To reduce bacterial adhesion, the APC flash-free bracket adhesive system with low adhesive excess might be beneficial. APC flash-free brackets reduce the bacterial colonization in the bracket environment. A lower number of bacteria can minimize white spot lesions in the bracket environment. APC flash-free brackets tend to form marginal gaps between the bracket adhesive and the tooth.

ABSTRACT Lanthanides (Ln) are the most recently described life metals and are central to methylotrophy (type of metabolism in which organic substrates without carbon-carbon bonds serve as carbon and energy source) in diverse taxa. We recently characterized a novel, Ln-dependent, and Ln-accumulating methylotroph, Beijerinckiaceae bacterium RH AL1, which requires lighter Ln (La, Ce, Nd) for methanol oxidation. Starting from two sets of incubations, one with different La concentrations (50 nM and 1 µM) and one with different Ln elements [La, Nd, or an Ln cocktail (containing Ce, Nd, Dy, Ho, Er, Yb)], we could show that La concentration and different Ln elements strongly affect gene expression and intracellular Ln accumulation. Differential gene expression analysis revealed that up to 41% of the encoded genes were differentially expressed. The effects of La concentration and Ln elements were not limited to Ln-dependent methanol oxidation but reached into many aspects of metabolism. We observed that Ln influence the flagellar and chemotactic machinery and that they affect polyhydroxyalkanoate biosynthesis. The most differentially expressed genes included lanM, coding for the well-characterized lanthanide-binding protein lanmodulin, and a glucose dehydrogenase gene linked to the conversion of β-D-glucose to D-glucono-1,5-lactone, a known potential metal chelator. Electron microscopy, together with RNAseq, suggested that Beijerinckiaceae bacterium RH AL1 can discriminate between Ln elements and that they are differently taken up and accumulated. The discrimination of Ln and links between Ln and various aspects of metabolism underline a broader physiological role for Ln in Beijerinckiaceae bacterium RH AL1. IMPORTANCE Since its discovery, Ln-dependent metabolism in bacteria attracted a lot of attention due to its bio-metallurgical application potential regarding Ln recycling and circular economy. The physiological role of Ln is mostly studied dependent on presence and absence. Comparisons of how different (utilizable) Ln affect metabolism have rarely been done. We noticed unexpectedly pronounced changes in gene expression caused by different Ln supplementation. Our research suggests that strain RH AL1 distinguishes different Ln elements and that the effect of Ln reaches into many aspects of metabolism, for instance, chemotaxis, motility, and polyhydroxyalkanoate metabolism. Our findings regarding Ln accumulation suggest a distinction between individual Ln elements and provide insights relating to intracellular Ln homeostasis. Understanding comprehensively how microbes distinguish and handle different Ln elements is key for turning knowledge into application regarding Ln-centered biometallurgy.

BACKGROUND:enamel demineralization is a common side effect of orthodontic therapy with fixed braces. The aim of the present in vitro study was to compare a conventional adhesive system and a modern adhesive system (APC Flash-Free [FF] technology) with regard to the demineralization of enamel by Streptococcus sobrinus (S. sobrinus).METHODS:this in vitro study included premolar teeth and compared APC FF adhesive brackets (Group A, n = 15) with conventional adhesive brackets (Group B, n = 15) from the same company. Specimens were incubated with a positive control group (PCG, n = 5) and a negative control group (NCG, n = 5) in an S. sobrinus suspension for three weeks. To evaluate the grade of enamel demineralization, the samples were analyzed using a polarizing microscope.RESULTS:the test specimens of group B with conventionally bonded bracket adhesive showed significantly greater (+10.8 μm) demineralization with regard to the penetration depth of the demineralization than the PCG (p = 0.012). Thus, there was a difference from group A with the new bracket adhesive of the FF brackets (+7.29 μm). Significantly, demineralization was more pronounced cervically than coronally in both groups, and it occurred cervically more frequently than grade 3 demineralization (p = 0.001).CONCLUSIONS:it seems plausible that new orthodontic bracket adhesives and the modern FF adhesive system positively contribute to the reduction in enamel demineralization during orthodontic treatment.

Magnetic hyperthermia can cause localized thermal eradication of several solid cancers. However, a localized and homogenous deposition of high concentrations of magnetic nanomaterials into the tumor stroma and tumor cells is mostly required. Poorly responsive cancers such as the pancreatic adenocarcinomas are hallmarked by a rigid stroma and poor perfusion to therapeutics and nanomaterials. Hence, approaches that enhance the infiltration of magnetic nanofluids into the tumor stroma convey potentials to improve thermal tumor therapy. We studied the influence of the matrix-modulating enzymes hyaluronidase and collagenase on the uptake of magnetic nanoparticles by pancreatic cancer cells and 3D spheroids thereof, and the overall impact on magnetic heating and cell death. Furthermore, we validated the effect of hyaluronidase on magnetic hyperthermia treatment of heterotopic pancreatic cancer models in mice. Treatment of cultured cells with the enzymes caused higher uptake of magnetic nanoparticles (MNP) as compared to nontreated cells. For example, hyaluronidase caused a 28% increase in iron deposits per cell. Consequently, the thermal doses (cumulative equivalent minutes at 43 °C, CEM43) increased by 15–23% as compared to heat dose achieved for cells treated with magnetic hyperthermia without using enzymes. Likewise, heat-induced cell death increased. In in vivo studies, hyaluronidase-enhanced infiltration and distribution of the nanoparticles in the tumors resulted in moderate heating levels (CEM43 of 128 min as compared to 479 min) and a slower, but persistent decrease in tumor volumes over time after treatment, as compared to comparable treatment without hyaluronidase. The results indicate that hyaluronidase, in particular, improves the infiltration of magnetic nanoparticles into pancreatic cancer models, impacts their thermal treatment and cell depletion, and hence, will contribute immensely in the fight against pancreatic and many other adenocarcinomas.

At least 7 proteorhodopsin sequences ofOxyrrhis marinawere recently proven in bands obtained by sucrose density gradient centrifugation, and MS analyses revealed that the bands consisted almost of pure, native proteorhodopsins (Rhiel et al.2020). The proteorhodopsin fractions, i.e., bands B2, B3, and B4 were subjected to transmission electron microscopy. Negative staining revealed that band B2 consisted most likely of monomeric/oligomeric proteorhodopsins with particle dimensions of about 6 nm. Negative staining, freeze-fracture, and cryo-transmission electron microscopy revealed that bands B3 and B4 consisted of vesicular, sheet-like, and cup-shaped structures which all seemed to be composed of protein. Frequently, ring-like protein aggregates were registered at higher magnifications. They measured about 4 nm in diameter with a tiny hole of 1.5 nm in the middle. The bands B2, B3, and B4 were pooled and used to raise an antiserum. Immunoelectron microscopy resulted in intense labeling of the isolated structures. Immunofluorescence light microscopy of formaldehyde-fixedOxyrrhiscells resulted in intense labeling of the cell periphery. Some cell internal structures became labeled, too. Immunoelectron microscopy of freeze-fractured cells revealed that most likely the membranes of the amphiesmal vesicles were labeled at the cell periphery, while the cell internal label seemed to originate from the food vacuoles.