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1.
Nature ; 630(8017): 654-659, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38839965

RESUMEN

Emissions reduction and greenhouse gas removal from the atmosphere are both necessary to achieve net-zero emissions and limit climate change1. There is thus a need for improved sorbents for the capture of carbon dioxide from the atmosphere, a process known as direct air capture. In particular, low-cost materials that can be regenerated at low temperatures would overcome the limitations of current technologies. In this work, we introduce a new class of designer sorbent materials known as 'charged-sorbents'. These materials are prepared through a battery-like charging process that accumulates ions in the pores of low-cost activated carbons, with the inserted ions then serving as sites for carbon dioxide adsorption. We use our charging process to accumulate reactive hydroxide ions in the pores of a carbon electrode, and find that the resulting sorbent material can rapidly capture carbon dioxide from ambient air by means of (bi)carbonate formation. Unlike traditional bulk carbonates, charged-sorbent regeneration can be achieved at low temperatures (90-100 °C) and the sorbent's conductive nature permits direct Joule heating regeneration2,3 using renewable electricity. Given their highly tailorable pore environments and low cost, we anticipate that charged-sorbents will find numerous potential applications in chemical separations, catalysis and beyond.


Asunto(s)
Dióxido de Carbono , Dióxido de Carbono/análisis , Dióxido de Carbono/química , Dióxido de Carbono/aislamiento & purificación , Adsorción , Electrodos , Hidróxidos/química , Atmósfera/química , Carbonatos/química , Aire , Temperatura , Carbón Orgánico/química , Porosidad , Carbono/química
2.
Nature ; 630(8016): 360-367, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38778109

RESUMEN

Implanted biomaterials and devices face compromised functionality and efficacy in the long term owing to foreign body reactions and subsequent formation of fibrous capsules at the implant-tissue interfaces1-4. Here we demonstrate that an adhesive implant-tissue interface can mitigate fibrous capsule formation in diverse animal models, including rats, mice, humanized mice and pigs, by reducing the level of infiltration of inflammatory cells into the adhesive implant-tissue interface compared to the non-adhesive implant-tissue interface. Histological analysis shows that the adhesive implant-tissue interface does not form observable fibrous capsules on diverse organs, including the abdominal wall, colon, stomach, lung and heart, over 12 weeks in vivo. In vitro protein adsorption, multiplex Luminex assays, quantitative PCR, immunofluorescence analysis and RNA sequencing are additionally carried out to validate the hypothesis. We further demonstrate long-term bidirectional electrical communication enabled by implantable electrodes with an adhesive interface over 12 weeks in a rat model in vivo. These findings may offer a promising strategy for long-term anti-fibrotic implant-tissue interfaces.


Asunto(s)
Materiales Biocompatibles , Fibrosis , Reacción a Cuerpo Extraño , Prótesis e Implantes , Adhesivos Tisulares , Animales , Femenino , Humanos , Masculino , Ratones , Ratas , Pared Abdominal , Adsorción , Materiales Biocompatibles/química , Colon , Electrodos Implantados , Fibrosis/patología , Fibrosis/prevención & control , Reacción a Cuerpo Extraño/prevención & control , Reacción a Cuerpo Extraño/patología , Corazón , Pulmón , Ratones Endogámicos C57BL , Especificidad de Órganos , Reacción en Cadena de la Polimerasa , Ratas Sprague-Dawley , Estómago , Porcinos , Factores de Tiempo , Adhesivos Tisulares/química , Técnica del Anticuerpo Fluorescente , Reproducibilidad de los Resultados , Análisis de Secuencia de ARN
3.
Nature ; 618(7966): 733-739, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37344647

RESUMEN

Control of adhesion is a striking feature of living matter that is of particular interest regarding technological translation1-3. We discovered that entropic repulsion caused by interfacial orientational fluctuations of cholesterol layers restricts protein adsorption and bacterial adhesion. Moreover, we found that intrinsically adhesive wax ester layers become similarly antibioadhesive when containing small quantities (under 10 wt%) of cholesterol. Wetting, adsorption and adhesion experiments, as well as atomistic simulations, showed that repulsive characteristics depend on the specific molecular structure of cholesterol that encodes a finely balanced fluctuating reorientation at the interface of unconstrained supramolecular assemblies: layers of cholesterol analogues differing only in minute molecular variations showed markedly different interfacial mobility and no antiadhesive effects. Also, orientationally fixed cholesterol layers did not resist bioadhesion. Our insights provide a conceptually new physicochemical perspective on biointerfaces and may guide future material design in regulation of adhesion.


Asunto(s)
Adhesión Bacteriana , Colesterol , Entropía , Proteínas , Adsorción , Proteínas/química , Humectabilidad , Colesterol/química
4.
Proc Natl Acad Sci U S A ; 121(7): e2316569121, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38330016

RESUMEN

Clay minerals are implicated in the retention of biomolecules within organic matter in many soil environments. Spectroscopic studies have proposed several mechanisms for biomolecule adsorption on clays. Here, we employ molecular dynamics simulations to investigate these mechanisms in hydrated adsorbate conformations of montmorillonite, a smectite-type clay, with ten biomolecules of varying chemistry and structure, including sugars related to cellulose and hemicellulose, lignin-related phenolic acid, and amino acids with different functional groups. Our molecular modeling captures biomolecule-clay and biomolecule-biomolecule interactions that dictate selectivity and competition in adsorption retention and interlayer nanopore trapping, which we determine experimentally by NMR and X-ray diffraction, respectively. Specific adsorbate structures are important in facilitating the electrostatic attraction and Van der Waals energies underlying the hierarchy in biomolecule adsorption. Stabilized by a network of direct and water-bridged hydrogen bonds, favorable electrostatic interactions drive this hierarchy whereby amino acids with positively charged side chains are preferentially adsorbed on the negatively charged clay surface compared to the sugars and carboxylate-rich aromatics and amino acids. With divalent metal cations, our model adsorbate conformations illustrate hydrated metal cation bridging of carboxylate-containing biomolecules to the clay surface, thus explaining divalent cation-promoted adsorption from our experimental data. Adsorption experiments with a mixture of biomolecules reveal selective inhibition in biomolecule adsorption, which our molecular modeling attributes to electrostatic biomolecule-biomolecule pairing that is more energetically favorable than the biomolecule-clay complex. In sum, our findings highlight chemical and structural features that can inform hypotheses for predicting biomolecule adsorption at water-clay interfaces.


Asunto(s)
Simulación de Dinámica Molecular , Agua , Arcilla , Adsorción , Agua/química , Electricidad Estática , Aminoácidos , Azúcares
5.
Proc Natl Acad Sci U S A ; 121(11): e2307809121, 2024 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-38437543

RESUMEN

Rapid advances in nucleic acid therapies highlight the immense therapeutic potential of genetic therapeutics. Lipid nanoparticles (LNPs) are highly potent nonviral transfection agents that can encapsulate and deliver various nucleic acid therapeutics, including but not limited to messenger RNA (mRNA), silencing RNA (siRNA), and plasmid DNA (pDNA). However, a major challenge of targeted LNP-mediated systemic delivery is the nanoparticles' nonspecific uptake by the liver and the mononuclear phagocytic system, due partly to the adsorption of endogenous serum proteins onto LNP surfaces. Tunable LNP surface chemistries may enable efficacious delivery across a range of organs and cell types. Here, we describe a method to electrostatically adsorb bioactive polyelectrolytes onto LNPs to create layered LNPs (LLNPs). LNP cores varying in nucleic acid cargo and component lipids were stably layered with four biologically relevant polyanions: hyaluronate (HA), poly-L-aspartate (PLD), poly-L-glutamate (PLE), and polyacrylate (PAA). We further investigated the impact of the four surface polyanions on the transfection and uptake of mRNA- and pDNA-loaded LNPs in cell cultures. PLD- and PLE-LLNPs increased mRNA transfection twofold over unlayered LNPs in immune cells. HA-LLNPs increased pDNA transfection rates by more than twofold in epithelial and immune cells. In a healthy C57BL/6 murine model, PLE- and HA-LLNPs increased transfection by 1.8-fold to 2.5-fold over unlayered LNPs in the liver and spleen. These results suggest that LbL assembly is a generalizable, highly tunable platform to modify the targeting specificity, stability, and transfection efficacy of LNPs, as well as incorporate other charged targeting and therapeutic molecules into these systems.


Asunto(s)
Liposomas , Nanopartículas , Animales , Ratones , Polielectrolitos , Adsorción , Electricidad Estática , Transfección , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Ácido Glutámico
6.
Annu Rev Biochem ; 80: 101-23, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21438688

RESUMEN

Bacteria and eukaryotic cells contain geometry-sensing tools in their cytosol: protein motifs or domains that recognize the curvature, concave or convex, deep or shallow, of lipid membranes. These sensors contrast with classical lipid-binding domains by their extended structure and, sometimes, counterintuitive chemistry. Among the sensors are long amphipathic helices, such as the ALPS motif and the N-terminal region of α-synuclein, whose apparent "design defects" translate into a remarkable ability to specifically adsorb to the surface of small vesicles. Fundamental differences in the lipid composition of membranes of the early and late secretory pathways probably explain why some sensors use mostly electrostatics whereas others take advantage of the hydrophobic effect. Membrane curvature sensors help to organize very diverse reactions, such as lipid transfer between membranes, the tethering of vesicles at the Golgi apparatus, and the assembly-disassembly cycle of protein coats.


Asunto(s)
Membrana Celular/ultraestructura , Lípidos de la Membrana/química , Proteínas de la Membrana/química , Adsorción , Animales , Vesículas Cubiertas por Proteínas de Revestimiento/química , Membrana Celular/química , Proteínas Activadoras de GTPasa/metabolismo , Membrana Dobles de Lípidos/química , Modelos Moleculares , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , alfa-Sinucleína/química
7.
Nature ; 577(7790): 327-336, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31942051

RESUMEN

Bacteria are under immense evolutionary pressure from their viral invaders-bacteriophages. Bacteria have evolved numerous immune mechanisms, both innate and adaptive, to cope with this pressure. The discovery and exploitation of CRISPR-Cas systems have stimulated a resurgence in the identification and characterization of anti-phage mechanisms. Bacteriophages use an extensive battery of counter-defence strategies to co-exist in the presence of these diverse phage defence mechanisms. Understanding the dynamics of the interactions between these microorganisms has implications for phage-based therapies, microbial ecology and evolution, and the development of new biotechnological tools. Here we review the spectrum of anti-phage systems and highlight their evasion by bacteriophages.


Asunto(s)
Bacterias/inmunología , Bacterias/virología , Bacteriófagos/inmunología , Interacciones Microbiota-Huesped/inmunología , Adsorción , Animales , Bacterias/crecimiento & desarrollo , Bacteriófagos/metabolismo , Sistemas CRISPR-Cas/fisiología , Humanos
8.
Proc Natl Acad Sci U S A ; 120(3): e2209979120, 2023 01 17.
Artículo en Inglés | MEDLINE | ID: mdl-36626554

RESUMEN

The electrolysis of nitrate reduction to ammonia (NRA) is promising for obtaining value-added chemicals and mitigating environmental concerns. Recently, catalysts with high-performance ammonia synthesis from nitrate has been achieved under alkaline or acidic conditions. However, NRA in neutral solution still suffers from the low yield rate and selectivity of ammonia due to the low binding affinity and nucleophilicity of NO3-. Here, we confirmed that the in-situ-generated Fe(II) ions existed as specifically adsorbed cations in the inner Helmholtz plane (IHP) with a low redox potential. Inspired by this, a strategy (Fe-IHP strategy) was proposed to enhance NRA activity by tuning the affinity of the electrode-electrolyte interface. The specifically adsorbed Fe(II) ions [SA-Fe(II)] greatly alleviated the electrostatic repulsion around the interfaceresulting in a 10-fold lower in the adsorption-free energy of NO3- when compared to the case without SA-Fe(II). Meanwhile, the modulated interface accelerated the kinetic mass transfer process by 25 folds compared to the control. Under neutral conditions, a Faraday efficiency of 99.6%, a selectivity of 99%, and an extremely high NH3 yield rate of 485.8 mmol h-1 g-1 FeOOH were achieved. Theoretical calculations and in-situ Raman spectroscopy confirmed the electron-rich state of the SA-Fe(II) donated to p orbitals of N atom and favored the hydrogenation of *NO to *NOH for promoting the formation of high-selectivity ammonia. In sum, these findings complement the textbook on the specific adsorption of cations and provide insights into the design of low-cost NRA catalysts with efficient ammonia synthesis.


Asunto(s)
Amoníaco , Nitratos , Electrólitos , Adsorción , Hierro , Compuestos Ferrosos
9.
Proc Natl Acad Sci U S A ; 120(29): e2305705120, 2023 07 18.
Artículo en Inglés | MEDLINE | ID: mdl-37428922

RESUMEN

The assimilation of antibiotic resistance genes (ARGs) by pathogenic bacteria poses a severe threat to public health. Here, we reported a dual-reaction-site-modified CoSA/Ti3C2Tx (single cobalt atoms immobilized on Ti3C2Tx MXene) for effectively deactivating extracellular ARGs via peroxymonosulfate (PMS) activation. The enhanced removal of ARGs was attributed to the synergistic effect of adsorption (Ti sites) and degradation (Co-O3 sites). The Ti sites on CoSA/Ti3C2Tx nanosheets bound with PO43- on the phosphate skeletons of ARGs via Ti-O-P coordination interactions, achieving excellent adsorption capacity (10.21 × 1010 copies mg-1) for tetA, and the Co-O3 sites activated PMS into surface-bond hydroxyl radicals (•OHsurface), which can quickly attack the backbones and bases of the adsorbed ARGs, resulting in the efficient in situ degradation of ARGs into inactive small molecular organics and NO3. This dual-reaction-site Fenton-like system exhibited ultrahigh extracellular ARG degradation rate (k > 0.9 min-1) and showed the potential for practical wastewater treatment in a membrane filtration process, which provided insights for extracellular ARG removal via catalysts design.


Asunto(s)
Antibacterianos , Genes Bacterianos , Antibacterianos/farmacología , Cobalto , Titanio/farmacología , Adsorción , Aguas Residuales , Farmacorresistencia Microbiana/genética
10.
J Virol ; 98(3): e0000724, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38305153

RESUMEN

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease, which is responsible for enormous economic losses to the global pig industry. Although vaccination has been used to prevent PRV infection, the effectiveness of vaccines has been greatly diminished with the emergence of PRV variants. Therefore, there is an urgent need to develop anti-PRV drugs. Polyethylenimine (PEI) is a cationic polymer and has a wide range of antibacterial and antiviral activities. This study found that a low dose of 1 µg/mL of the 25-kDa linear PEI had significantly specific anti-PRV activity, which became more intense with increasing concentrations. Mechanistic studies revealed that the viral adsorption stage was the major target of PEI without affecting viral entry, replication stages, and direct inactivation effects. Subsequently, we found that cationic polymers PEI and Polybrene interfered with the interaction between viral proteins and cell surface receptors through electrostatic interaction to exert the antiviral function. In conclusion, cationic polymers such as PEI can be a category of options for defense against PRV. Understanding the anti-PRV mechanism also deepens host-virus interactions and reveals new drug targets for anti-PRV.IMPORTANCEPolyethylenimine (PEI) is a cationic polymer that plays an essential role in the host immune response against microbial infections. However, the specific mechanisms of PEI in interfering with pseudorabies virus (PRV) infection remain unclear. Here, we found that 25-kDa linear PEI exerted mechanisms of antiviral activity and the target of its antiviral activity was mainly in the viral adsorption stage. Correspondingly, the study demonstrated that PEI interfered with the virus adsorption stage by electrostatic adsorption. In addition, we found that cationic polymers are a promising novel agent for controlling PRV, and its antiviral mechanism may provide a strategy for the development of antiviral drugs.


Asunto(s)
Antivirales , Herpesvirus Suido 1 , Polietileneimina , Electricidad Estática , Animales , Adsorción/efectos de los fármacos , Antivirales/química , Antivirales/farmacología , Herpesvirus Suido 1/efectos de los fármacos , Herpesvirus Suido 1/metabolismo , Polietileneimina/química , Polietileneimina/farmacología , Seudorrabia/tratamiento farmacológico , Seudorrabia/virología , Porcinos/virología , Enfermedades de los Porcinos/virología
11.
Proc Natl Acad Sci U S A ; 119(39): e2211544119, 2022 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-36122236

RESUMEN

Engineered systems designed to remove CO2 from the atmosphere need better adsorbents. Here, we report on zeolite-based adsorbents for the capture of low-concentration CO2. Synthetic zeolites with the mordenite (MOR)-type framework topology physisorb CO2 from low concentrations with fast kinetics, low heat of adsorption, and high capacity. The MOR-type zeolites can have a CO2 capacity of up to 1.15 and 1.05 mmol/g for adsorption from 400 ppm CO2 at 30 °C, measured by volumetric and gravimetric methods, respectively. A structure-performance study demonstrates that Na+ cations in the O33 site located in the side-pocket of the MOR-type framework, that is accessed through a ring of eight tetrahedral atoms (either Si4+ or Al3+: eight-membered ring [8MR]), is the primary site for the CO2 uptake at low concentrations. The presence of N2 and O2 shows negligible impact on CO2 adsorption in MOR-type zeolites, and the capacity increases to ∼2.0 mmol/g at subambient temperatures. By using a series of zeolites with variable topologies, we found the size of the confining pore space to be important for the adsorption of trace CO2. The results obtained here show that the MOR-type zeolites have a number of desirable features for the capture of CO2 at low concentrations.


Asunto(s)
Zeolitas , Adsorción , Silicatos de Aluminio , Dióxido de Carbono
12.
Proc Natl Acad Sci U S A ; 119(49): e2209545119, 2022 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-36442119

RESUMEN

The origin of ice slipperiness has been a matter of great controversy for more than a century, but an atomistic understanding of ice friction is still lacking. Here, we perform computer simulations of an atomically smooth substrate sliding on ice. In a large temperature range between 230 and 266 K, hydrophobic sliders exhibit a premelting layer similar to that found at the ice/air interface. On the contrary, hydrophilic sliders show larger premelting and a strong increase of the first adsorption layer. The nonequilibrium simulations show that premelting films of barely one-nanometer thickness are sufficient to provide a lubricating quasi-liquid layer with rheological properties similar to bulk undercooled water. Upon shearing, the films display a pattern consistent with lubricating Couette flow, but the boundary conditions at the wall vary strongly with the substrate's interactions. Hydrophobic walls exhibit large slip, while hydrophilic walls obey stick boundary conditions with small negative slip. By compressing ice above atmospheric pressure, the lubricating layer grows continuously, and the rheological properties approach bulk-like behavior. Below 260 K, the equilibrium premelting films decrease significantly. However, a very large slip persists on the hydrophobic walls, while the increased friction on hydrophilic walls is sufficient to melt ice and create a lubrication layer in a few nanoseconds. Our results show that the atomic-scale frictional behavior of ice is a combination of spontaneous premelting, pressure melting, and frictional heating.


Asunto(s)
Hielo , Tortugas , Animales , Fricción , Lubrificación , Películas Cinematográficas , Adsorción
13.
Proc Natl Acad Sci U S A ; 119(42): e2210857119, 2022 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-36215494

RESUMEN

The adsorption of ions to water-hydrophobe interfaces influences a wide range of phenomena, including chemical reaction rates, ion transport across biological membranes, and electrochemical and many catalytic processes; hence, developing a detailed understanding of the behavior of ions at water-hydrophobe interfaces is of central interest. Here, we characterize the adsorption of the chaotropic thiocyanate anion (SCN-) to two prototypical liquid hydrophobic surfaces, water-toluene and water-decane, by surface-sensitive nonlinear spectroscopy and compare the results against our previous studies of SCN- adsorption to the air-water interface. For these systems, we observe no spectral shift in the charge transfer to solvent spectrum of SCN-, and the Gibb's free energies of adsorption for these three different interfaces all agree within error. We employed molecular dynamics simulations to develop a molecular-level understanding of the adsorption mechanism and found that the adsorption for SCN- to both water-toluene and water-decane interfaces is driven by an increase in entropy, with very little enthalpic contribution. This is a qualitatively different mechanism than reported for SCN- adsorption to the air-water and graphene-water interfaces, wherein a favorable enthalpy change was the main driving force, against an unfavorable entropy change.


Asunto(s)
Grafito , Agua , Adsorción , Alcanos , Aniones , Iones/química , Solventes , Tiocianatos/química , Tolueno , Agua/química
14.
Proc Natl Acad Sci U S A ; 119(31): e2109718119, 2022 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-35901206

RESUMEN

Primary nucleation is the fundamental event that initiates the conversion of proteins from their normal physiological forms into pathological amyloid aggregates associated with the onset and development of disorders including systemic amyloidosis, as well as the neurodegenerative conditions Alzheimer's and Parkinson's diseases. It has become apparent that the presence of surfaces can dramatically modulate nucleation. However, the underlying physicochemical parameters governing this process have been challenging to elucidate, with interfaces in some cases having been found to accelerate aggregation, while in others they can inhibit the kinetics of this process. Here we show through kinetic analysis that for three different fibril-forming proteins, interfaces affect the aggregation reaction mainly through modulating the primary nucleation step. Moreover, we show through direct measurements of the Gibbs free energy of adsorption, combined with theory and coarse-grained computer simulations, that overall nucleation rates are suppressed at high and at low surface interaction strengths but significantly enhanced at intermediate strengths, and we verify these regimes experimentally. Taken together, these results provide a quantitative description of the fundamental process which triggers amyloid formation and shed light on the key factors that control this process.


Asunto(s)
Amiloide , Proteínas Amiloidogénicas , Adsorción , Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Proteínas Amiloidogénicas/metabolismo , Amiloidosis/patología , Humanos , Cinética , Enfermedades Neurodegenerativas/patología
15.
Nano Lett ; 24(13): 3930-3936, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38513221

RESUMEN

Detecting weakly adsorbing molecules via label-free surface-enhanced Raman scattering (SERS) has presented a significant challenge. To address this issue, we propose a novel approach for creating tricomponent SERS substrates using dual-rim nanorings (DRNs) made of Au, Ag, and CuO, each possessing distinct functionalities. Our method involves depositing different metals on Pt nanoring skeletons to obtain each nanoring with varying surface compositions while maintaining a similar size and shape. Next, the mixture of these nanorings is transferred into a monolayer assembly with homogeneous intermixing on a solid substrate. The surface of the CuO DRNs has dangling bonds (Cu2+) that facilitate the strong adsorption of carboxylates through the formation of chelating bonds, while the combination of Au and Ag DRNs significantly enhances the SERS signal intensity through a strong coupling effect. Notably, the tricomponent assemblies enable the successful SERS-based analysis of biomolecules such as amino acids, proteins, nucleobases, and nucleotides.


Asunto(s)
Oro , Nanopartículas del Metal , Oro/química , Espectrometría Raman/métodos , Plata/química , Adsorción , Nanopartículas del Metal/química
16.
Biophys J ; 123(12): 1519-1530, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38664968

RESUMEN

The type II pneumocytes of the lungs secrete a mixture of lipids and proteins that together acts as a surfactant. The material forms a thin film on the surface of the liquid layer that lines the alveolar air sacks. When compressed by the decreasing alveolar surface area during exhalation, the films reduce surface tension to exceptionally low levels. Pulmonary surfactant is essential for preserving the integrity of the barrier between alveolar air and capillary blood during normal breathing. This review focuses on the major biophysical processes by which endogenous pulmonary surfactant achieves its function and the mechanisms involved in those processes. Vesicles of pulmonary surfactant adsorb rapidly from the alveolar liquid to form the interfacial film. Interfacial insertion, which requires the hydrophobic surfactant protein SP-B, proceeds by a process analogous to the fusion of two vesicles. When compressed, the adsorbed film desorbs slowly. Constituents remain at the surface at high interfacial concentrations that reduce surface tensions well below equilibrium levels. We review the models proposed to explain how pulmonary surfactant achieves both the rapid adsorption and slow desorption characteristic of a functional film.


Asunto(s)
Surfactantes Pulmonares , Surfactantes Pulmonares/metabolismo , Surfactantes Pulmonares/química , Humanos , Animales , Modelos Biológicos , Adsorción , Fenómenos Biofísicos , Tensión Superficial
17.
Biophys J ; 123(4): 451-463, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-37924206

RESUMEN

One of the earliest living systems was likely based on RNA ("the RNA world"). Mineral surfaces have been postulated to be an important environment for the prebiotic chemistry of RNA. In addition to adsorbing RNA and thus potentially reducing the chance of parasitic takeover through limited diffusion, minerals have been shown to promote a range of processes related to the emergence of life, including RNA polymerization, peptide bond formation, and self-assembly of vesicles. In addition, self-cleaving ribozymes have been shown to retain activity when adsorbed to the clay mineral montmorillonite. However, simulation studies suggest that adsorption to minerals is likely to interfere with RNA folding and, thus, function. To further evaluate the plausibility of a mineral-adsorbed RNA world, here we studied the effect of the synthetic clay montmorillonite K10 on the malachite green RNA aptamer, including binding of the clay to malachite green and RNA, as well as on the formation of secondary structures in model RNA and DNA oligonucleotides. We evaluated the fluorescence of the aptamer complex, adsorption to the mineral, melting curves, Förster resonance energy transfer interactions, and 1H-NMR signals to study the folding and functionality of these nucleic acids. Our results indicate that while some base pairings are unperturbed, the overall folding and binding of the malachite green aptamer are substantially disrupted by montmorillonite. These findings suggest that minerals would constrain the structures, and possibly the functions, available to an adsorbed RNA world.


Asunto(s)
Bentonita , ARN , Colorantes de Rosanilina , Bentonita/química , ARN/química , Arcilla , Silicatos de Aluminio/química , Adsorción , Minerales/química
18.
Biophys J ; 123(7): 901-908, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38449310

RESUMEN

A cell-penetrating peptide (CPP) is a short amino-acid sequence capable of efficiently translocating across the cellular membrane of mammalian cells. However, the potential of CPPs as a delivery vector is hampered by the strong reduction of its translocation efficiency when it bears an attached molecular cargo. To overcome this problem, we used previously developed diblock copolymers of elastin-like polypeptides (ELPBCs), which we end functionalized with TAT (transactivator of transcription), an archetypal CPP built from a positively charged amino acid sequence of the HIV-1 virus. These ELPBCs self-assemble into micelles at a specific temperature and present the TAT peptide on their corona. These micelles can recover the lost membrane affinity of TAT and can trigger interactions with the membrane despite the presence of a molecular cargo. Herein, we study the influence of membrane surface charge on the adsorption of TAT-functionalized ELP micelles onto giant unilamellar vesicles (GUVs). We show that the TAT-ELPBC micelles show an increased binding constant toward negatively charged membranes compared to neutral membranes, but no translocation is observed. The affinity of the TAT-ELPBC micelles for the GUVs displays a stepwise dependence on the lipid charge of the GUV, which, to our knowledge, has not been reported previously for interactions between peptides and lipid membranes. By unveiling the key steps controlling the interaction of an archetypal CPP with lipid membranes, through regulation of the charge of the lipid bilayer, our results pave the way for a better design of delivery vectors based on CPPs.


Asunto(s)
Péptidos de Penetración Celular , Micelas , Animales , Polipéptidos Similares a Elastina , Adsorción , Membrana Dobles de Lípidos/química , Péptidos/química , Liposomas Unilamelares/química , Péptidos de Penetración Celular/química , Mamíferos/metabolismo
19.
J Am Chem Soc ; 146(14): 10023-10031, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38554097

RESUMEN

Single-atom nanozyme-based catalytic therapy is of great interest in the field of tumor catalytic therapy; however, their development suffers from the low affinity of nanozymes to the substrates (H2O2 or O2), leading to deficient catalytic activity in the tumor microenvironment. Herein, we report a new strategy for precisely tuning the d-band center of dual-atomic sites to enhance the affinity of metal atomic sites and substrates on a class of edge-rich N-doped porous carbon dual-atomic sites Fe-Mn (Fe1Mn1-NCe) for greatly boosting multiple-enzyme-like catalytic activities. The as-made Fe1Mn1-NCe achieved a much higher catalytic efficiency (Kcat/Km = 4.01 × 105 S-1·M-1) than Fe1-NCe (Kcat/Km = 2.41 × 104 S-1·M-1) with an outstanding stability of over 90% activity retention after 1 year, which is the best among the reported dual-atom nanozymes. Theoretical calculations reveal that the synergetic effect of Mn upshifts the d-band center of Fe from -1.113 to -0.564 eV and enhances the adsorption capacity for the substrate, thus accelerating the dissociation of H2O2 and weakening the O-O bond on O2. We further demonstrated that the superior enzyme-like catalytic activity of Fe1Mn1-NCe combined with photothermal therapy could effectively inhibit tumor growth in vivo, with an inhibition rate of up to 95.74%, which is the highest value among the dual-atom artificial enzyme therapies reported so far.


Asunto(s)
Peróxido de Hidrógeno , Neoplasias , Humanos , Adsorción , Carbono , Catálisis , Microambiente Tumoral
20.
J Am Chem Soc ; 146(15): 10478-10488, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38578196

RESUMEN

During biomedical applications, nanozymes, exhibiting enzyme-like characteristics, inevitably come into contact with biological fluids in living systems, leading to the formation of a protein corona on their surface. Although it is acknowledged that molecular adsorption can influence the catalytic activity of nanozymes, there is a dearth of understanding regarding the impact of the protein corona on nanozyme activity and its determinant factors. In order to address this gap, we employed the AuNR@Pt@PDDAC [PDDAC, poly(diallyldimethylammonium chloride)] nanorod (NR) as a model nanozyme with multiple activities, including peroxidase, oxidase, and catalase-mimetic activities, to investigate the inhibitory effects of the protein corona on the catalytic activity. After the identification of major components in the plasma protein corona on the NR, we observed that spherical proteins and fibrous proteins induced distinct inhibitory effects on the catalytic activity of nanozymes. To elucidate the underlying mechanism, we uncovered that the adsorbed proteins assembled on the surface of the nanozymes, forming protein networks (PNs). Notably, the PNs derived from fibrous proteins exhibited a screen mesh-like structure with smaller pore sizes compared to those formed by spherical proteins. This structural disparity resulted in a reduced efficiency for the permeation of substrate molecules, leading to a more robust inhibition in activity. These findings underscore the significance of the protein shape as a crucial factor influencing nanozyme activity. This revelation provides valuable insights for the rational design and application of nanozymes in the biomedical fields.


Asunto(s)
Nanoestructuras , Corona de Proteínas , Escleroproteínas , Peroxidasa , Adsorción , Colorantes , Catálisis
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