RESUMEN
To date, studies on the thermodynamic and kinetic processes that underlie biological function and nanomachine actuation in biological- and biology-inspired molecular constructs have primarily focused on photothermal heating of ensemble systems, highlighting the need for probes that are localized within the molecular construct and capable of resolving single-molecule response. Here we present an experimental demonstration of wavelength-selective, localized heating at the single-molecule level using the surface plasmon resonance of a 15 nm gold nanoparticle (AuNP). Our approach is compatible with force-spectroscopy measurements and can be applied to studies of the single-molecule thermodynamic properties of DNA origami nanomachines as well as biomolecular complexes. We further demonstrate wavelength selectivity and establish the temperature dependence of the reaction coordinate for base-pair disruption in the shear-rupture geometry, demonstrating the utility and flexibility of this approach for both fundamental studies of local (nanometer-scale) temperature gradients and rapid and multiplexed nanomachine actuation.
Asunto(s)
Oro , Nanopartículas del Metal , Oro/química , Pinzas Ópticas , Calefacción , Nanopartículas del Metal/química , ADN/químicaRESUMEN
DNA nanostructures are a promising tool to deliver molecular payloads to cells. DNA origami structures, where long single-stranded DNA is folded into a compact nanostructure, present an attractive approach to package genes; however, effective delivery of genetic material into cell nuclei has remained a critical challenge. Here, we describe the use of DNA nanostructures encoding an intact human gene and a fluorescent protein encoding gene as compact templates for gene integration by CRISPR-mediated homology-directed repair (HDR). Our design includes CRISPR-Cas9 ribonucleoprotein binding sites on DNA nanostructures to increase shuttling into the nucleus. We demonstrate efficient shuttling and genomic integration of DNA nanostructures using transfection and electroporation. These nanostructured templates display lower toxicity and higher insertion efficiency compared to unstructured double-stranded DNA templates in human primary cells. Furthermore, our study validates virus-like particles as an efficient method of DNA nanostructure delivery, opening the possibility of delivering nanostructures in vivo to specific cell types. Together, these results provide new approaches to gene delivery with DNA nanostructures and establish their use as HDR templates, exploiting both their design features and their ability to encode genetic information. This work also opens a door to translate other DNA nanodevice functions, such as biosensing, into cell nuclei.
Asunto(s)
Técnicas de Transferencia de Gen , Nanoestructuras , Transporte Activo de Núcleo Celular , Sistemas CRISPR-Cas , ADN/genética , Edición Génica/métodos , Genoma , HumanosRESUMEN
OBJECTIVE: To determine how the severity of prior history (Hx) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection influences postoperative outcomes after major elective inpatient surgery. BACKGROUND: Surgical guidelines instituted early in the coronavirus disease 2019 (COVID-19) pandemic recommended a delay in surgery of up to 8 weeks after an acute SARS-CoV-2 infection. This was based on the observation of elevated surgical risk after recovery from COVID-19 early in the pandemic. As the pandemic shifts to an endemic phase, it is unclear whether this association remains, especially for those recovering from asymptomatic or mildly symptomatic COVID-19. METHODS: Utilizing the National COVID Cohort Collaborative, we assessed postoperative outcomes for adults with and without a Hx of COVID-19 who underwent major elective inpatient surgery between January 2020 and February 2023. COVID-19 severity and time from infection to surgery were each used as independent variables in multivariable logistic regression models. RESULTS: This study included 387,030 patients, of whom 37,354 (9.7%) were diagnosed with preoperative COVID-19. Hx of COVID-19 was found to be an independent risk factor for adverse postoperative outcomes even after a 12-week delay for patients with moderate and severe SARS-CoV-2 infection. Patients with mild COVID-19 did not have an increased risk of adverse postoperative outcomes at any time point. Vaccination decreased the odds of respiratory failure. CONCLUSIONS: Impact of COVID-19 on postoperative outcomes is dependent on the severity of illness, with only moderate and severe disease leading to a higher risk of adverse outcomes. Existing perioperative policies should be updated to include consideration of COVID-19 disease severity and vaccination status.
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COVID-19 , Adulto , Humanos , COVID-19/epidemiología , SARS-CoV-2 , Pacientes Internos , Procedimientos Quirúrgicos Electivos/efectos adversos , Factores de RiesgoRESUMEN
As the coronavirus disease 2019 (COVID-19) pandemic progresses to an endemic phase, a greater number of patients with a history of COVID-19 will undergo surgery. Major adverse cardiovascular and cerebrovascular events (MACE) are the primary contributors to postoperative morbidity and mortality; however, studies assessing the relationship between a previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and postoperative MACE outcomes are limited. Here, we analyzed retrospective data from 457,804 patients within the N3C Data Enclave, the largest national, multi-institutional data set on COVID-19 in the United States. However, 7.4% of patients had a history of COVID-19 before surgery. When comorbidities, age, race, and risk of surgery were controlled, patients with preoperative COVID-19 had an increased risk for 30-day postoperative MACE. MACE risk was influenced by an interplay between COVID-19 disease severity and time between surgery and infection; in those with mild disease, MACE risk was not increased even among those undergoing surgery within 4 wk following infection. In those with moderate disease, risk for postoperative MACE was mitigated 8 wk after infection, whereas patients with severe disease continued to have elevated postoperative MACE risk even after waiting for 8 wk. Being fully vaccinated decreased the risk for postoperative MACE in both patients with no history of COVID-19 and in those with breakthrough COVID-19 infection. Together, our results suggest that a thorough assessment of the severity, vaccination status, and timing of SARS-CoV-2 infection must be a mandatory part of perioperative stratification.NEW & NOTEWORTHY With an increasing proportion of patients undergoing surgery with a prior history of COVID-19, it is crucial to understand the impact of SARS-CoV-2 infection on postoperative cardiovascular/cerebrovascular risk. Our work assesses a large, national, multi-institutional cohort of patients to highlight that COVID-19 infection increases risk for postoperative major adverse cardiovascular and cerebrovascular events (MACE). MACE risk is influenced by an interplay between disease severity and time between infection and surgery, and full vaccination reduces the risk for 30-day postoperative MACE. These results highlight the importance of stratifying time-to-surgery guidelines based on disease severity.
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COVID-19 , Humanos , Estados Unidos , COVID-19/complicaciones , COVID-19/diagnóstico , Estudios Retrospectivos , SARS-CoV-2 , Infección Irruptiva , Complicaciones Posoperatorias/epidemiologíaRESUMEN
Lectins are carbohydrate-binding proteins belonging to the Leguminosae family. In this family stand out proteins extracted from species belonging to Diocleinae subtribe, which includes, for example, the seed lectin from Dioclea violacea (DVL) and the jack bean lectin Concanavalin A (ConA). Here, we report the photosynthesis of silver/silver chloride nanoparticles (NPs) assisted by ConA and DVL. The syntheses were simple processes using a green-chemistry approach. Under electron microscopy, NPs heterogeneous in size, nearly spherical and covered by a thin lectin corona, were observed. Both NPs assisted by lectins were capable to cause strong rabbit erythrocytes agglutination with the same titers of hemagglutinating activities. These results indicate that both lectins maintained their biological activities even after association with the NPs and therefore are able to interact with biological membrane carbohydrates. However, for rabbit erythrocytes treated with proteolytic enzymes were observed different titers of hemagglutinating activities, suggesting differences in the spatial arrangement of the lectins on the surface of the NPs. This study provides evidences that these hybrid lectin-coated silver/silver chloride NPs can be used for selective recognition and interaction with membrane carbohydrates and others biotechnological applications.
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Lectinas , Lectinas de Plantas , Animales , Conejos , Lectinas/química , Lectinas de Plantas/farmacología , Lectinas de Plantas/química , Lectinas de Plantas/metabolismo , Plata/farmacología , Carbohidratos/química , FotosíntesisRESUMEN
Single molecule force spectroscopy is a powerful approach to probe the structure, conformational changes, and kinetic properties of biological and synthetic macromolecules. However, common approaches to apply forces to biomolecules require expensive and cumbersome equipment and relatively large probes such as beads or cantilevers, which limits their use for many environments and makes integrating with other methods challenging. Furthermore, existing methods have key limitations such as an inability to apply compressive forces on single molecules. We report a nanoscale DNA force spectrometer (nDFS), which is based on a DNA origami hinge with tunable mechanical and dynamic properties. The angular free energy landscape of the nDFS can be engineered across a wide range through substitution of less than 5% of the strand components. We further incorporate a removable strut that enables reversible toggling of the nDFS between open and closed states to allow for actuated application of tensile and compressive forces. We demonstrate the ability to apply compressive forces by inducing a large bend in a 249bp DNA molecule, and tensile forces by inducing DNA unwrapping of a nucleosome sample. These results establish a versatile tool for force spectroscopy and robust methods for designing nanoscale mechanical devices with tunable force application.
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ADN/química , Nanoestructuras/química , Bioingeniería , Fenómenos Biomecánicos , Nucleosomas/química , Análisis EspectralRESUMEN
DNA origami (DO) nanotechnology enables the construction of precise nanostructures capable of functionalization with small molecule drugs, nucleic acids, and proteins, suggesting a promising platform for biomedical applications. Despite the potential for drug and vaccine delivery, the impact of DO vehicles on immunogenicity in vivo is not well understood. Here, two DO vehicles, a flat triangle and a nanorod, at varying concentrations are evaluated in vitro and with a repeated dosing regimen administered at a high dose in vivo to study early and late immunogenicity. The studies show normal CD11b+ myeloid cell populations preferentially internalize DO in vitro. DO structures distribute well systemically in vivo, elicit a modest pro-inflammatory immune response that diminishes over time and are nontoxic as shown by weight, histopathology, lack of cytokine storm, and a complete biochemistry panel at the day 10 end point. The results take critical steps to characterize the biological response to DO and suggest that DO vehicles represent a promising platform for drug delivery and vaccine development where immunogenicity should be a key consideration.
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Nanoestructuras , ADN/química , Sistemas de Liberación de Medicamentos/métodos , Nanoestructuras/química , Nanotecnología/métodos , Conformación de Ácido Nucleico , Preparaciones Farmacéuticas , ProteínasRESUMEN
Recently, DNA has been used to make nanodevices for a myriad of applications across fields including medicine, nanomanufacturing, synthetic biology, biosensing and biophysics. However, current DNA nanodevices rely primarily on geometric design, and it remains challenging to rationally design functional properties such as force-response or actuation behaviour. Here we report an iterative design pipeline for DNA assemblies that integrates computer-aided engineering based on coarse-grained molecular dynamics with a versatile computer-aided design approach that combines top-down automation with bottom-up control over geometry. This intuitive framework allows for rapid construction of large, multicomponent assemblies from three-dimensional models with finer control over the geometrical, mechanical and dynamical properties of the DNA structures in an automated manner. This approach expands the scope of structural complexity and enhances mechanical and dynamic design of DNA assemblies.
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Diseño Asistido por Computadora , ADN/química , Nanoestructuras/química , ADN/ultraestructura , Microscopía Electrónica de Transmisión , Simulación de Dinámica Molecular , NanotecnologíaRESUMEN
The success of targeted drug delivery systems still requires a detailed understanding about the biological consequences of self-developed biomolecular coronas around them, since this is the surface that interacts with living cells. Herein, we report the behavior of carbohydrate-decorated amphiphilic nanoparticles in a plasma environment with regard to the formation and biological consequences of the protein corona. Naked amphiphilic nanoparticles were produced through the self-assembly of azido-PEO900-docosanoate molecules, and the coupling of N-acetylglucosamine via click chemistry enabled the fabrication of the corresponding bioactive glyco-nanostructures. Light scattering measurements, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, liquid chromatography-mass spectrometry, and the Pierce BCA protein assay all confirmed the presence of protein coronas around the self-assembled nanoparticles, regardless of the presence of the sugar residues, although it reduces the amount of adsorbed proteins. The protein coronas were formed mainly by human serum albumin, complement proteins, apolipoproteins, immunoglobulins, and proteins involved in the coagulation cascade (fibrinogen and prothrombin). While the presence of these protein coronas significantly reduced cellular uptake of the amphiphilic assemblies, they also notably reduced the cytotoxic and hemolytic effects that result from the contact of the nanoparticles with living cells. Accordingly, we highlight that protein coronas should not always be treated as artifacts that have to be avoided because they can also provide beneficial effects.
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Nanopartículas/química , Corona de Proteínas/química , Adsorción , Cromatografía Liquida/métodos , Electroforesis en Gel de Poliacrilamida , Células HeLa , Humanos , Espectrometría de Masas/métodos , Microscopía Electrónica de TransmisiónRESUMEN
DNA origami mechanisms offer promising tools for precision nanomanipulation of molecules or nanomaterials. Recent advances have extended the function of individual DNA origami devices to material scales via hierarchical assemblies. However, achieving rapid and precise control of large conformational changes in hierarchical assemblies remains a critical challenge. Here, we demonstrate a method for controlling DNA origami-nanoparticle assemblies through a multiscale approach, in which nanoparticles impart control on the conformation of individual DNA origami mechanisms, whereas DNA origami assemblies control the conformation of nanoparticle arrays. Specifically, we show that the angular distributions of DNA origami hinge mechanisms are tunable as a function of nanoparticle size and distance from the hinge vertex. We selectively adjust the affinity of nanoparticle binding sites, resulting in hinge actuation via DNA melting without releasing the nanoparticle, thereby enabling rapid and reversible temperature-based actuation. Finally, we demonstrate this rapid actuation in DNA origami-nanoparticle arrays of length scales extending over a micron. These results provide guiding principles toward the design of dynamic, DNA-origami hierarchical materials capable of storing and releasing mechanical energy.
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ADN/química , Nanopartículas/química , Nanopartículas/ultraestructura , Tamaño de la PartículaRESUMEN
Glycoconjugates are versatile entities used for the manufacturing of targeted drug delivery nanocontainers because of their outstanding capability to bind to lectins, which are proteins that can be found overexpressed in the membranes of unhealthy cells. The assisted attachment to pathological cells can further enable a more efficient intracellular delivery of loaded active agents, thereby reducing side effects that commonly compromise chemotherapies. In this framework, azide-terminated polyethylene oxide (PEO) chains coupled to a 22-carbon chain were synthesized (azide-PEO900-docosanoate). The resulting amphiphile was further functionalized by introducing different sugar moieties to the PEO chains via the click chemistry approach. Sub-30 nm, negatively charged, and spherical nanoparticles were prepared in water by self-assembly of the synthesized molecules using the straightforward nanoprecipitation protocol. The produced entities do not induce hemolysis in red blood cells at c ≤ 200 µg mL-1, and they are not cytotoxic to healthy cells [telomerase immortalized rhesus fibroblasts (Telo-RF)] at c ≤ 50 µg mL-1. The sugar-decorated nanoparticles are less cytotoxic compared with their naked counterparts at the concentration range assessed. The kinetics of cellular uptake of both entities into normal (Telo-RF) and tumor (HeLa) cells were monitored via fluorescence microscopy and flow cytometry. The nanoparticles are internalized faster in cancer cells than in normal cells, regardless of functionalization. Moreover, the functionalized nanoparticles are internalized faster in HeLa cells, while the reverse was observed in healthy Telo-RF cells. The distinct surface characteristics of the assemblies create an opportunity to expedite the uptake of nanoparticles particularly by tumor cells, and this accordingly can lead to a more effective intracellular delivery of therapeutic molecules loaded into nanoparticle's reservoirs.
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Portadores de Fármacos/química , Glicoconjugados/química , Nanopartículas/química , Antineoplásicos/química , Antineoplásicos/metabolismo , Azidas/química , Transporte Biológico , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Portadores de Fármacos/efectos adversos , Sistemas de Liberación de Medicamentos/métodos , Citometría de Flujo , Células HeLa , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía Fluorescente , Nanopartículas/efectos adversos , Polietilenglicoles/químicaRESUMEN
Quantum dot (QD) biological imaging and sensing applications often require surface modification with single-stranded deoxyribonucleic acid (ssDNA) oligonucleotides. Furthermore, ssDNA conjugation can be leveraged for precision QD templating via higher-order DNA nanostructures to exploit emergent behaviors in photonic applications. Use of ssDNA-QDs across these platforms requires compact, controlled conjugation that engenders QD stability over a wide pH range and in solutions of high ionic strength. However, current ssDNA-QD conjugation approaches suffer from limitations, such as the requirement for thick coatings, low control over ssDNA labeling density, requirement of large amounts of ssDNA, or low colloidal or photostability, restraining implementation in many applications. Here, we combine thin, multidentate, phytochelatin-3 (PC3) QD passivation techniques with strain-promoted copper-free alkyne-azide click chemistry to yield functional ssDNA-QDs with high stability. This process was broadly applicable across QD sizes (i.e., λem = 540, 560, 600 nm), ssDNA lengths (i.e., 10-16 base pairs, bps), and sequences (poly thymine, mixed bps). The resulting compact ssDNA-QDs displayed a fluorescence quenching efficiency of up to 89% by hybridization with complementary ssDNA-AuNPs. Furthermore, ssDNA-QDs were successfully incorporated with higher-order DNA origami nanostructure templates. Thus, this approach, combining PC3 passivation with click chemistry, generates ssDNA-PC3-QDs that enable emergent QD properties in DNA-based devices and applications.
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ADN de Cadena Simple/química , Nanocompuestos/química , Puntos Cuánticos/química , Alquinos/química , Azidas/química , Compuestos de Cadmio/química , Química Clic , Fluorescencia , Oro/química , Nanopartículas del Metal/química , Hibridación de Ácido Nucleico , Oligodesoxirribonucleótidos/química , Fitoquelatinas/química , Poli T/química , Compuestos de Selenio/química , Sulfuros/química , Propiedades de Superficie , Compuestos de Zinc/químicaRESUMEN
Significant progress in DNA nanotechnology has accelerated the development of molecular machines with functions like macroscale machines. However, the mobility of DNA self-assembled nanorobots is still dramatically limited due to challenges with designing and controlling nanoscale systems with many degrees of freedom. Here, an origami-inspired method to design transformable DNA nanomachines is presented. This approach integrates stiff panels formed by bundles of double-stranded DNA connected with foldable creases formed by single-stranded DNA. To demonstrate the method, a DNA version of the paper origami mechanism called a waterbomb base (WBB) consisting of six panels connected by six joints is constructed. This nanoscale WBB can follow four distinct motion paths to transform between five distinct configurations including a flat square, two triangles, a rectangle, and a fully compacted trapezoidal shape. To achieve this, the sequence specificity of DNA base-pairing is leveraged for the selective actuation of joints and the ion-sensitivity of base-stacking interactions is employed for the flattening of joints. In addition, higher-order assembly of DNA WBBs into reconfigurable arrays is achieved. This work establishes a foundation for origami-inspired design for next generation synthetic molecular robots and reconfigurable nanomaterials enabling more complex and controllable motion.
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ADN/química , Nanoestructuras/química , Nanotecnología/métodosRESUMEN
The development of nanovehicles for intracellular drug delivery is strongly bound to the understating and control of nanoparticles cellular uptake process, which in turn is governed by surface chemistry. In this study, we explored the synthesis, characterization, and cellular uptake of block copolymer assemblies consisting of a pH-responsive poly[2-(diisopropylamino)ethyl methacrylate] (PDPA) core stabilized by three different biocompatible hydrophilic shells (a zwitterionic type poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) layer, a highly hydrated poly(ethylene oxide) (PEO) layer with stealth effect, and an also proven nontoxic and nonimmunogenic poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) layer). All particles had a spherical core-shell structure. The largest particles with the thickest hydrophilic stabilizing shell obtained from PMPC40-b-PDPA70 were internalized to a higher level than those smaller in size and stabilized by PEO or PHPMA and produced from PEO122-b-PDPA43 or PHPMA64-b-PDPA72, respectively. Such a behavior was confirmed among different cell lines, with assemblies being internalized to a higher degree in cancer (HeLa) as compared to healthy (Telo-RF) cells. This fact was mainly attributed to the stronger binding of PMPC to cell membranes. Therefore, cellular uptake of nanoparticles at the sub-100 nm size range may be chiefly governed by the chemical nature of the stabilizing layer rather than particles size and/or shell thickness.
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Materiales Biocompatibles/química , Materiales Biocompatibles/metabolismo , Nanopartículas/química , Polímeros/química , Polímeros/metabolismo , Materiales Biocompatibles/toxicidad , Transporte Biológico , Células HeLa , Hemólisis/efectos de los fármacos , Humanos , Polímeros/toxicidad , Propiedades de SuperficieRESUMEN
DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate stiff double-stranded DNA components and flexible single-stranded DNA components to constrain motion along a single degree of freedom and demonstrate the ability to tune the flexibility and range of motion. Multiple joints with simple 1D motion were then integrated into higher order mechanisms. One mechanism is a crank-slider that couples rotational and linear motion, and the other is a Bennett linkage that moves between a compacted bundle and an expanded frame configuration with a constrained 3D motion path. Finally, we demonstrate distributed actuation of the linkage using DNA input strands to achieve reversible conformational changes of the entire structure on â¼ minute timescales. Our results demonstrate programmable motion of 2D and 3D DNA origami mechanisms constructed following a macroscopic machine design approach.
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ADN/química , Fenómenos Biomecánicos , Conformación de Ácido NucleicoRESUMEN
The prospective use of the block copolymers poly(ethylene oxide)113-b-poly[2-(diethylamino)ethyl methacrylate]50 (PEO113-b-PDEA50) and poly[oligo(ethylene glycol)methyl ether methacrylate]70-b-poly[oligo(ethylene glycol)methyl ether methacrylate10-co-2-(diethylamino)ethyl methacrylate47-co-2-(diisopropylamino)ethyl methacrylate47] (POEGMA70-b-P(OEGMA10-co-DEA47-co-DPA47)) as nonviral gene vectors was evaluated. The polymers are able to properly condense DNA into nanosized particles (RH ≈ 75 nm), which are marginally cytotoxic and can be uptaken by cells. However, the green fluorescent protein (GFP) expression assays evidenced that DNA delivery is essentially negligible meaning that intracellular trafficking hampers efficient gene release. Subsequently, we demonstrate that cellular uptake and particularly the quantity of GFP-positive cells are substantially enhanced when the block copolymer polyplexes are produced and further supplemented by BPEI chains (branched polyethylenimine). The dynamic light scattering/electrophoretic light scattering/isothermal titration calorimetry data suggest that such a strategy allows the adsorption of BPEI onto the surface of the polyplexes, and this phenomenon is responsible for increasing the size and surface charge of the assemblies. Nevertheless, most of the BPEI chains remain freely diffusing in the systems. The biological assays confirmed that cellular uptake is enhanced in the presence of BPEI and principally, the free highly charged polymer chains play the central role in intracellular trafficking and gene transfection. These investigations pointed out that the transfection efficiency versus cytotoxicity issue can be balanced by a mixture of BPEI and less cytotoxic agents such as for instance the proposed block copolymers.
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Técnicas de Transferencia de Gen , Vectores Genéticos/metabolismo , Metacrilatos/química , Nanopartículas/metabolismo , Polietilenglicoles/química , Polietileneimina/química , Ácidos Polimetacrílicos/química , Animales , Cationes/química , Línea Celular Transformada , Fibroblastos/citología , Fibroblastos/metabolismo , Expresión Génica , Genes Reporteros , Vectores Genéticos/síntesis química , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Macaca mulatta , Nanopartículas/química , Tamaño de la Partícula , Electricidad EstáticaRESUMEN
Deoxyribonucleic acid (DNA) origami is a method for the bottom-up self-assembly of complex nanostructures for applications, such as biosensing, drug delivery, nanopore technologies, and nanomechanical devices. Effective design of such nanostructures requires a good understanding of their mechanical behavior. While a number of studies have focused on the mechanical properties of DNA origami structures, considering defects arising from molecular self-assembly is largely unexplored. In this paper, we present an automated computational framework to analyze the impact of such defects on the structural integrity of a model DNA origami nanoplate. The proposed computational approach relies on a noniterative conforming to interface-structured adaptive mesh refinement (CISAMR) algorithm, which enables the automated transformation of a binary image of the nanoplate into a high fidelity finite element model. We implement this technique to quantify the impact of defects on the mechanical behavior of the nanoplate by performing multiple simulations taking into account varying numbers and spatial arrangements of missing DNA strands. The analyses are carried out for two types of loading: uniform tensile displacement applied on all the DNA strands and asymmetric tensile displacement applied to strands at diagonal corners of the nanoplate.
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ADN/química , Ensayo de Materiales , Fenómenos Mecánicos , Nanoestructuras , Automatización , Resistencia a la TracciónRESUMEN
Many cancers show primary or acquired drug resistance due to the overexpression of efflux pumps. A novel mechanism to circumvent this is to integrate drugs, such as anthracycline antibiotics, with nanoparticle delivery vehicles that can bypass intrinsic tumor drug-resistance mechanisms. DNA nanoparticles serve as an efficient binding platform for intercalating drugs (e.g., anthracyclines doxorubicin and daunorubicin, which are widely used to treat acute leukemias) and enable precise structure design and chemical modifications, for example, for incorporating targeting capabilities. Here, DNA nanostructures are utilized to circumvent daunorubicin drug resistance at clinically relevant doses in a leukemia cell line model. The fabrication of a rod-like DNA origami drug carrier is reported that can be controllably loaded with daunorubicin. It is further directly verified that nanostructure-mediated daunorubicin delivery leads to increased drug entry and retention in cells relative to free daunorubicin at equal concentrations, which yields significantly enhanced drug efficacy. Our results indicate that DNA origami nanostructures can circumvent efflux-pump-mediated drug resistance in leukemia cells at clinically relevant drug concentrations and provide a robust DNA nanostructure design that could be implemented in a wide range of cellular applications due to its remarkably fast self-assembly (≈5 min) and excellent stability in cell culture conditions.
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Aductos de ADN/química , Aductos de ADN/farmacología , Daunorrubicina/química , Daunorrubicina/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Leucemia/patología , Nanoestructuras/química , Conformación de Ácido Nucleico , Animales , Aductos de ADN/ultraestructura , Doxorrubicina/farmacología , Sistemas de Liberación de Medicamentos , Endocitosis/efectos de los fármacos , Células HL-60 , Caballos , Humanos , Sustancias Intercalantes/química , Lisosomas/efectos de los fármacos , Lisosomas/metabolismo , Modelos Biológicos , Nanoestructuras/ultraestructuraRESUMEN
Structural DNA nanotechnology provides a feasible technique for the design and fabrication of complex geometries even exhibiting controllable dynamic behavior. Recently we have demonstrated the possibility of implementing macroscopic engineering design approaches to construct DNA origami mechanisms (DOM) with programmable motion and tunable flexibility. Here, we implement the design of compliant DNA origami mechanisms to extend from prescribing motion to prescribing an energy landscape. Compliant mechanisms facilitate motion via deformation of components with tunable stiffness resulting in well-defined mechanical energy stored in the structure. We design, fabricate, and characterize a DNA origami nanostructure with an energy landscape defined by two stable states (local energy minima) separated by a designed energy barrier. This nanostructure is a four-bar bistable mechanism with two undeformed states. Traversing between those states requires deformation, and hence mechanical energy storage, in a compliant arm of the linkage. The energy barrier for switching between two states was obtained from the conformational distribution based on a Boltzmann probability function and closely follows a predictive mechanical model. Furthermore, we demonstrated the ability to actuate the mechanism into one stable state via additional DNA inputs and then release the actuation via DNA strand displacement. This controllable multistate system establishes a foundation for direct design of energy landscapes that regulate conformational dynamics similar to biomolecular complexes.