Oriented Nanoarchitectonics of Bacteriorhodopsin for Enhancing ATP Generation in a Fo F1 -ATPase-Based Assembly System.

Energy conversion plays an important role in the metabolism of photosynthetic organisms. Improving energy transformation by promoting a proton gradient has been a great challenge for a long time. In the present study, we realize a directional proton migration through the construction of oriented bacteriorhodopsin (BR) microcapsules coated by Fo F1 -ATPase molecular motors through layer-by-layer (LBL) assembly. The changes in the conformation of BR under illumination lead to proton transfer in a radial direction, which generates a higher proton gradient to drive the synthesis of adenosine triphosphate (ATP) by Fo F1 -ATPase. Furthermore, to promote the photosynthetic activity, optically matched quantum dots were introduced into the artificial coassembly system of BR and Fo F1 -ATPase. Such a design creates a new path for the use of light energy.

Whole-GUV patch-clamping.

Studying how the membrane modulates ion channel and transporter activity is challenging because cells actively regulate membrane properties, whereas existing in vitro systems have limitations, such as residual solvent and unphysiologically high membrane tension. Cell-sized giant unilamellar vesicles (GUVs) would be ideal for in vitro electrophysiology, but efforts to measure the membrane current of intact GUVs have been unsuccessful. In this work, two challenges for obtaining the "whole-GUV" patch-clamp configuration were identified and resolved. First, unless the patch pipette and GUV pressures are precisely matched in the GUV-attached configuration, breaking the patch membrane also ruptures the GUV. Second, GUVs shrink irreversibly because the membrane/glass adhesion creating the high-resistance seal (>1 GΩ) continuously pulls membrane into the pipette. In contrast, for cell-derived giant plasma membrane vesicles (GPMVs), breaking the patch membrane allows the GPMV contents to passivate the pipette surface, thereby dynamically blocking membrane spreading in the whole-GMPV mode. To mimic this dynamic passivation mechanism, beta-casein was encapsulated into GUVs, yielding a stable, high-resistance, whole-GUV configuration for a range of membrane compositions. Specific membrane capacitance measurements confirmed that the membranes were truly solvent-free and that membrane tension could be controlled over a physiological range. Finally, the potential for ion transport studies was tested using the model ion channel, gramicidin, and voltage-clamp fluorometry measurements were performed with a voltage-dependent fluorophore/quencher pair. Whole-GUV patch-clamping allows ion transport and other voltage-dependent processes to be studied while controlling membrane composition, tension, and shape.

Crystallographic snapshot of an arrested intermediate in the biomimetic activation of CO2.

The design of molecular catalysts that mimic the behavior of enzymes is a topical field of activity in emerging technologies, and can lead to an improved understanding of biological systems. Herein, we report how the bulky arms of the cations in [(n C4 H9 )4 N](+) [HCO3 ](-) give rise to a host scaffold that emulates the substrate binding sites in carbonic anhydrase enzymes, affording a unique glimpse of an arrested intermediate in the base-mediated binding and activation of CO2 .

Enhanced Reactivities of Iron(IV)-Oxo Porphyrin Species in Oxidation Reactions Promoted by Intramolecular Hydrogen-Bonding.

High-valent iron-oxo species are one of the common intermediates in both biological and biomimetic catalytic oxidation reactions. Recently, hydrogen-bonding (H-bonding) has been proved to be critical in determining the selectivity and reactivity. However, few examples have been established for mechanistic insights into the H-bonding effect. Moreover, intramolecular H-bonding effect on both C-H activation and oxygen atom transfer (OAT) reactions in synthetic porphyrin model system has not been investigated yet. In this study, a series of heme-containing iron(IV)-oxo porphyrin species with or without intramolecular H-bonding are synthesized and characterized. Kinetic studies revealed that intramolecular H-bonding can significantly enhance the reactivity of iron(IV)-oxo species in OAT, C-H activation, and electron-transfer reactions. This unprecedented unified H-bonding effect is elucidated by theoretical calculations, which showed that intramolecular H-bonding interactions lower the energy of the anti-bonding orbital of iron(IV)-oxo porphyrin species, resulting in the enhanced reactivities in oxidation reactions irrespective of the reaction type. To the best of the knowledge, this is the first extensive investigation on the intramolecular H-bonding effect in heme system. The results show that H-bonding interactions have a unified effect with iron(IV)-oxo porphyrin species in all three investigated reactions.

Cuproptosis-immunotherapy using PD-1 overexpressing T cell membrane-coated nanosheets efficiently treats tumor.

The cuproptosis cell death pathway brings fresh opportunities for tumor therapy. However, efficient and targeted cuproptosis induction in tumors is still a challenge. Unfortunately, the well-known cuproptosis initiator, disulfiram and copper complex (DSF/Cu2+), also increases PD-L1 level in tumors, which may diminish the final therapeutic outcome. In this study, DSF/Cu2+-loading MXene nanosheets are coated with PD-1 overexpressing T cell membrane to generate CuX-P system. CuX-P could recognize and stick to PD-L1 on tumor cells like a patch, which promotes the endocytosis of both CuX-P and PD-L1 by tumor cells. Following internalization and release of DSF/Cu2+ in the cytoplasm, PD-L1 expression is upregulated. However, due to the presence of CuX-P in the tumor microenvironment, the then supplemented PD-L1 on tumor surface again binds CuX-P for internalization. This feedback loop keeps blocking and consuming the PD-L1 on tumor surface and promotes the enrichment of CuX-P in tumors to induce cuproptosis. After CuX-P treatment with laser irradiation, strong anti-tumor immune responses are stimulated in a mouse model with triple-negative breast cancer. Thus, this study develops a tumor-targeted biomimetic system that offers simultaneous cuproptosis killing, photothermal therapy (PTT) and immunotherapy in mice.

Norfloxacin and gentamicin degradation catalyzed by manganese porphyrins under mild conditions: the importance of toxicity assessment.

The current work assessed the degradation degree and the degradation products derived from norfloxacin (NOR) and gentamicin (GEN) using iodosylbenzene and iodobenzene diacetate, in the presence of manganese porphyrin as catalysts. Better results for NOR degradation (> 80%) were obtained when more hydrophobic porphyrins were employed. ß-brominated manganese porphyrins showed a lower GEN degradation (~ 25%) than the non-brominated ones (~ 35%), probably due to their steric hindrance. In any case, complete mineralization was achieved neither for NOR nor for GEN, and the assignment of the generated products, complemented by the study of their toxicity, was an important step performed. From the obtained results, no correlation was found between the number of identified products and the reported toxicity value (rSpearman,NOR = 0.006; p value = 0.986 and rSpearman,GEN = - 0,198; p value = 0.583), which reinforces the idea of synergism and antagonistic phenomena. The higher degradation degree could have led to products of lower steric hindrance and easier penetration into the A. fischeri cells, which subsequently led to an increase in toxicity for these experiments. In most cases, the products presented higher toxicity than the original compound, which raises a concern about their occurrence in environmental matrices.

Inspiring biomimetic system based on red blood cell membrane vesicles for effective curcumin loading and release.

The aim of this study is to introduce an inspiring biomimetic system based on the red blood cell membrane (RBCM) vesicles for improved encapsulation efficiency and release of curcumin (Cur). Here, the role of the sonication time (0.5, 1.5, 3 and 5 min) on the properties of RBCM-CUR vesicles is investigated. It is determined that the hydrodynamic vesicle size, zeta potential, and release behavior are tunable by changing the sonication time. Noticeably, the average size of vesicles decreased from 163.0 ± 21 nm to 116.3 ± 16 nm by increasing the sonication time from 0.5 to 5 min. Moreover, the drug release value, after 24 h incubation, enhances from 57 to 99% with the expansion of sonication from 0.5 to 5 min. Additionally, the entrapment efficiency of Cur as a model drug is high in whole sonication time, owing to the amphiphilic nature of RBCM. Finally, the RBCM-CUR vesicles are not only cytocompatible, but also could support the attachment and proliferation of fibroblast cells in vitro. The RBCM based system for delivery of Cur could be a promising system for the wound healing applications.

The Biomimetic System of Oleanolic Acid and Oleic Acid at the Air-Water Interface-Interactions in Terms of Nanotechnology-Based Drug Delivery Systems.

Oleanolic acid (OLA) and oleic acid (OA) are ubiquitous in the plant kingdom, exhibiting a therapeutic effect on human health, and are components of novel pharmaceutical formulations. Since OLA has limited solubility, the utilization of nanotechnology-based drug delivery systems enhancing bioavailability is highly advantageous. We report on the interfacial behavior of the OLA:OA system at various molar ratios, using the Langmuir technique to assess the dependence of the molar composition on miscibility and rheological properties affecting film stability. Specifically, we evaluate the interfacial properties (morphology, thermodynamics, miscibility, and viscoelasticity) of the OLA:OA binary system in various molar ratios, and indicate how the OLA:OA system exhibits the most favorable molecular interactions. We apply the Langmuir monolayer technique along with the complementary techniques of Brewster angle microscopy, dilatational interfacial rheology, and excess free energy calculations. Results demonstrate that the properties of mixed monolayers depend on OLA:OA molar ratio. Most of the systems (OLA:OA 2:1, 1:1, 1:5) are assumed to be immiscible at surface pressures >10 mN/m. Moreover, the OLA:OA 1:2 is immiscible over the entire surface pressure range. However, the existence of miscibility between molecules of OLA and OA in the 5:1 for every surface pressure tested suggests that OA molecules incorporate into the OLA lattice structure, improving the stability of the mixed film. The results are discussed in terms of providing physicochemical insights into the behavior of the OLA:OA systems at the interface, which is of high interest in pharmaceutical design.

Artificial Compound Eye Systems and Their Application: A Review.

The natural compound eye system has many outstanding properties, such as a more compact size, wider-angle view, better capacity to detect moving objects, and higher sensitivity to light intensity, compared to that of a single-aperture vision system. Thanks to the development of micro- and nano-fabrication techniques, many artificial compound eye imaging systems have been studied and fabricated to inherit fascinating optical features of the natural compound eye. This paper provides a review of artificial compound eye imaging systems. This review begins by introducing the principle of the natural compound eye, and then, the analysis of two types of artificial compound eye systems. We equally present the applications of the artificial compound eye imaging systems. Finally, we suggest our outlooks about the artificial compound eye imaging system.

Integration of biochemical and topographic cues for the formation and spatial distribution of invadosomes in nasopharyngeal epithelial cells.

Invadosomes are invasive protrusions generated by cells which can secrete matrix metalloproteinases for focal digestion of extracellular matrix. They also aid invasive cancer cells in their transmigration through vascular endothelium. However, how the physical and chemical cues in a three-dimensional (3D) system signal the spatial localization of invadosomes remains largely unknown. Here we study the topographic guidance of invadosome formation in invasive nasopharyngeal cells under the stimulation of an inflammatory cytokine, TGF-ß1, using engineered gratings with different width and depth. We first report that TGF-ß1 can act as an external signal to upregulate the formation of invadosomes with a random distribution on a plane 2D surface. When the cells were seeded on parallel 3D gratings of 5 µm width and 1 µm depth, most of the invadosomes aligned to the edges of the gratings, indicating a topographic cue to the control of invadosome localization. While the number of invadosomes per cell were not upregulated when the cells were seeded on 3D topography, guidance of invadosomes localization to edges is correlated with cell migration directionality on 1 µm deep gratings. Invadosomes preferentially form at edges when the cells move at a lower speed and are guided along narrow gratings. The invadosomes forming at 3D edges also have a longer half-life than those forming on a plane surface. These data suggest that there are integrated biochemical and 3D geometric cues underlying the spatial regulation of invasive structures so as to elicit efficient invasion or metastasis of cells. STATEMENT OF SIGNIFICANCE: Nasopharyngeal cells were integrated with the biological cues and matrix topography to govern the activity and spatial distribution of invadosomes. The biochemical induction of invadosome formation by TGF-ß1 in nasopharyngeal cells was observed. When the cells were seeded on parallel 3D gratings, most of the invadosomes aligned to the edges of the gratings due to topographical induced invadosome localization. While the number of invadosomes per cell were not upregulated, guidance of invadosomes localization to edges is correlated with cell migration directionality on 1 µm deep gratings. Invadosomes preferentially form at edges with a higher stability when the cells are guided along narrow gratings. The integrated biochemical and 3D geometric cues could elicit efficient invasion or metastasis of cells.

Efficient atrazine degradation catalyzed by manganese porphyrins: Determination of atrazine degradation products and their toxicity evaluation by human blood cells test models.

Atrazine (ATZ) is an herbicide that has been considered an environmental pollutant worldwide. ATZ contaminates groundwaters and can persist in soils for up to a year causing several environmental and health problems. This study aimed to investigate ATZ degradation catalyzed by manganese porphyrins as biomimetic cytochrome P450 models. We used PhIO, PhI(OAc)2, H2O2, t-BuOOH, m-CPBA, or Oxone® as oxidant under mild conditions and evaluated a range of manganese porphyrins as catalyst. Concerning oxidant, iodosylbenzene provided the best result-ATZ degradation catalyzed by one of the studied manganese porphyrins in acetonitrile was as high as 47%. We studied the same catalyst/oxidant systems in natural water from a Brazilian river as solvent and obtained up to 100% ATZ degradation when iodobenzene diacetate was the oxidant, regardless of the manganese porphyrin. Besides the already known ATZ degradation products, we also identified unexpected degradation compounds (ring-opening products). Toxicity tests showed that the latter products were capable of proliferate blood cells because they did not show toxicity under the evaluated conditions.

Hypericin photodynamic activity in DPPC liposome. PART I: biomimetism of loading, location, interactions and thermodynamic properties.

Hypericin (Hyp) is a potential photosensitizer drug for Photodynamic Therapy (PDT). However, the high lipophilicity of Hyp prevents its preparation in water. To overcome the Hyp solubility problem, this study uses the liposomal vesicle of DPPC. Otherwise liposome is also one of the most employed artificial systems that mimetizes cell membranes. Our present focus is the interaction of Hyp into DPPC liposome as biomimetic system. We studied the loading, interaction, and localization of Hyp (2.8 µmol L-1) in DPPC (5.4 mmol L-1) liposomes, as well as the thermodynamic aspects of Hyp-liposomes. The Hyp addition to the DPPC liposome dispersion showed a Encapsulation Efficiency for [Hyp] = 2.8 µmol L-1 in [DPPC] = 5.3 mmol L-1 of 74.3% and 89.3% at 30.0 and 50.0 °C, respectively. The encapsulation profile obeys a pseudo first-order kinetic law, with a rate constant of 1.26 × 10-3 s-1 at 30.0 °C. Also the data suggests this reaction is preceded by an extremely rapid step. A study on the binding of Hyp/DPPC liposomes (Kb), performed at several temperatures, showed results of 4.8 and 18.5 × 103 L mol-1 at 293 and 323 K, respectively. Additionally, a decrease was observed in the ΔG of the Hyp/DPPC interaction (-20.6 and - 26.4 kL mol-1 at 293 and 323 K, respectively). The resulting ΔH > 0 with ΔS < 0 shows that the entropy is driven the process. Studies of Hyp location in the liposome at 298 K revealed the existence of two different Hyp populations with a Stern-Volmer constant (Ksv) of 4.65 and 1.87 L mol-1 using iodide as an aquo-suppressor at concentration ranged from 0 to 0.025 mol L-1 and from 0.025 to 0.150 mol L-1, respectively. Furthermore, studies of Fluorescence Resonance Energy Transfer, using DPH as a donor and Hyp as an acceptor, revealed that Hyp is allocated in different binding sites of the liposome. This is dependent on temperature. Thermal studies revealed that the Hyp/DPPC formulation presented reasonable stability. Size and morphological investigations showed that Hyp incorporation increases the average size of DPPC liposomes from 116 to 154 nm. The study demonstrated the ability of the Hyp-DPPC liposome as an interesting system for drug delivery system that can be applied to PDT.

Improvement in insulin absorption into gastrointestinal epithelial cells by using molecularly imprinted polymer nanoparticles: Microscopic evaluation and ultrastructure.

A molecularly imprinted polymer nanoparticle (MIP) was prepared by integrating a mixed functional monomer into a highly cross-linked polymer. The nanosized insulin as a template transferred into the binding cavities, anchored functional monomer(s) that the insulin structure formed within free space of the molecular size region by MIP nanoparticles. The oral administration with the insulin-loaded MIP resulted in higher fluorescence intensity of rhodamine-labeled insulin into the epithelial cells. We observed the correlation between the lipophilic domains of dye over the affected areas of sites with the interplay of the intestinal epithelial layer on the different intestinal sections. And, the detection with guinea pig anti-insulin antibody followed by goat anti-guinea pig antibody clearly elicited the efficient insulin function in the necessary biological milieu. The root mean square roughness of the MIP indicated difference of the surface density, significantly lower compared with the polymer attributed to the protein-mucin uptake that efficiently promoted the insulin penetration. Eventually electron microscopy data of the conjugated biotin-gold nanoparticles showed the transport of insulin across the intestinal epithelium via transcellular pathway, and the development of the pancreatic ß cell in the streptozocin-induced diabetic rats. Histopathological observation exhibited no obvious toxic effect after orally treated with MIP loaded insulin (100mg/kg) daily for 14days compared to control group. The use of an insulin-loaded MIP was proven to be an effective therapeutic protein delivery through transmucosal oral route.

Shape remodeling and blebbing of active cytoskeletal vesicles.

Morphological transformations of living cells, such as shape adaptation to external stimuli, blebbing, invagination, or tethering, result from an intricate interplay between the plasma membrane and its underlying cytoskeleton, where molecular motors generate forces. Cellular complexity defies a clear identification of the competing processes that lead to such a rich phenomenology. In a synthetic biology approach, designing a cell-like model assembled from a minimal set of purified building blocks would allow the control of all relevant parameters. We reconstruct actomyosin vesicles in which the coupling of the cytoskeleton to the membrane, the topology of the cytoskeletal network, and the contractile activity can all be precisely controlled and tuned. We demonstrate that tension generation of an encapsulated active actomyosin network suffices for global shape transformation of cell-sized lipid vesicles, which are reminiscent of morphological adaptations in living cells. The observed polymorphism of our cell-like model, such as blebbing, tether extrusion, or faceted shapes, can be qualitatively explained by the protein concentration dependencies and a force balance, taking into account the membrane tension, the density of anchoring points between the membrane and the actin network, and the forces exerted by molecular motors in the actin network. The identification of the physical mechanisms for shape transformations of active cytoskeletal vesicles sets a conceptual and quantitative benchmark for the further exploration of the adaptation mechanisms of cells.