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1.
Biosens Bioelectron ; 267: 116755, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39244838

RESUMEN

Precise and spatiotemporally controllable analysis of microRNA-21 in living cells is crucial for accurate diagnosis and effective treatment of related diseases. Herein, a near-infrared (NIR)-photoactivatable DNA nanomachine (PUCNPs-NH2/PEG-ZL-DNA) was constructed for the precise analysis and diagnosis of microRNA-21 in tumor cells. Peanut-shaped upconversion nanoparticles (PUCNPs) were employed as the carriers and activators for the intelligent DNA probe, specifically enabling the cleavage of the photocleavable linker (PC-linker) from the hairpin DNA probe (Hp-Dzy) upon exposure to 808 nm irradiation. In the presence of the target microRNA-21, the locker DNA hybridized with microRNA-21 and the DNAzymes was freed to hybridize with the looped portion of the hairpin DNA (Hp-1). Mg2+ was employed as the cofactor, facilitating the precise cleavage of Hp-1, which triggered the restoration of fluorescence signals. Subsequently, DNAzymes exhibited the competency to selectively recognize and engage with additional Hp-1, and the fluorescence signals were effectively amplified by the recycling process. Consequently, the DNA nanomachine exhibited a linear response to microRNA-21 concentrations ranging from 0.5 nM to 1.0 µM, achieving a remarkable detection limit (LOD) of 1.19 nM under the optimal conditions. This strategy is realized through the integration of photocontrollable upconversion nanotechnology with the signal amplification approach, showing feasible prospects for spatiotemporally precise and highly sensitive monitoring of microRNA in tumor cells.

2.
Anal Chim Acta ; 1319: 342962, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39122275

RESUMEN

MicroRNAs (miRNAs) are crucial regulators in various pathological and physiological processes, and their misregulation is a hallmark of many diseases. In this study, we introduce an advanced DNA nanomachine using split-type molecular beacons (STMBs) for sensitive detection of miR-21, a key biomarker in cancer diagnostics. Utilizing an innovative STMB-mediated cascade strand displacement amplification (STMB-CSDA) technique, our approach offers a powerful means for the precise quantification of miRNAs, using miR-21 as a primary example. The system operates through target-induced linkage of STMBs, initiating a series of strand displacement amplifications resulting in exponential signal amplification. Coupled with the precision of T4 DNA ligase, this mechanism translates minimal miRNA presence into significant fluorescence signals, offering detection sensitivity as low as 5.96 pM and a dynamic range spanning five orders of magnitude. Characterized by its high specificity, which includes the ability to identify single-base mismatches, along with its user-friendly design, our method represents a significant leap forward in miRNA analysis and molecular diagnostics. Its successful application in examining total RNA from cancer cells and clinical serum samples demonstrates its immense potential as a groundbreaking tool for early cancer detection and gene expression studies, paving the way for the next generation of non-invasive diagnostics in personalized healthcare.


Asunto(s)
MicroARNs , Neoplasias , Técnicas de Amplificación de Ácido Nucleico , Humanos , MicroARNs/análisis , MicroARNs/sangre , Neoplasias/diagnóstico , Neoplasias/genética , ADN/química , ADN/genética , Límite de Detección , Biomarcadores de Tumor/sangre , Biomarcadores de Tumor/genética
3.
Nano Lett ; 24(20): 6023-6030, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38739284

RESUMEN

Construction of diatomic rotors, which is crucial for artificial nanomachines, remains challenging due to surface constraints and limited chemical design. Here we report the construction of diatomic Cr-Cs and Fe-Cs rotors where a Cr or Fe atom switches around a Cs atom at the Sb surface of the newly discovered kagome superconductor CsV3Sb5. The switching rate is controlled by the bias voltage between the rotor and scanning tunneling microscope (STM) tip. The spatial distribution of rates exhibits C2 symmetry, possibly linked to the symmetry-breaking charge orders of CsV3Sb5. We have expanded the rotor construction to include different transition metals (Cr, Fe, V) and alkali metals (Cs, K). Remarkably, designed configurations of rotors are achieved through STM manipulation. Rotor orbits and quantum states are precisely controlled by tuning the inter-rotor distance. Our findings establish a novel platform for the controlled fabrication of atomic motors on symmetry-breaking quantum materials, paving the way for advanced nanoscale devices.

4.
Talanta ; 275: 126143, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38669960

RESUMEN

Accurate and sensitive detection of disease-associated proteins in early stage of patients plays an important role in timely treatment and successfully extending patients' lives. To meet this demand, we herein rationally designed a flexible target-induced DNA nanomachine operation (TIDNMO) sensor for the detection of proteins. The TIDNMO system was composed of DNA nanoswitch and DNA walker. Triplex DNA nanoswitch was triggered by specific target, followed by the release of the walking strand, which initiated the DNA walker amplification as signal output. In addition, the Exo III could drive walking strand autonomously move on gold nanoparticle surface to realize 2 orders of magnitude signal amplification. What's more, this sensor could transform its suitable functional recognition element of DNA nanoswitch to recognize other specific molecule and realize different targets sensing based on identical walking tracks. Considering the facile reporter elements and efficient amplification performance, the present DNA nanomachine as a sensor could achieve a detection limit of 68 pM for anti-Dig antibody, 0.95 pM for mucin-1 respectively, along with a superb specificity. Furthermore, the method reported here opened a new chapter in disease-related protein sensing for the development of clinical early diagnosis.


Asunto(s)
Técnicas Biosensibles , ADN , Oro , Nanopartículas del Metal , ADN/química , Oro/química , Humanos , Nanopartículas del Metal/química , Técnicas Biosensibles/métodos , Límite de Detección , Mucina-1/análisis , Exodesoxirribonucleasas/química , Exodesoxirribonucleasas/metabolismo , Nanotecnología , Técnicas de Amplificación de Ácido Nucleico/métodos
5.
Anal Chim Acta ; 1299: 342420, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38499416

RESUMEN

BACKGROUND: Telomerase is considered a biomarker for the early diagnosis and clinical treatment of cancer. The rapid and sensitive detection of telomerase activity is crucial to biological research, clinical diagnosis, and drug development. However, the main obstacles facing the current telomerase activity assay are the cumbersome and time-consuming procedure, the easy degradation of the telomerase RNA template and the need for additional proteases. Therefore, it is necessary to construct a new method for the detection of telomerase activity with easy steps, efficient reaction and strong anti-interference ability. RESULTS: Herein, an efficient, enzyme-free, economical, sensitive, fluorometric detection method for telomerase activity in one-step, named triggered-DNA (T-DNA) nanomachine, was created based on target-triggered DNAzyme-cleavage activity and catalytic molecular beacon (CMB). Telomerase served as a switch and extended few numbers of (TTAGGG)n repeat sequences to initiate the signal amplification in the T-DNA nanomachine, resulting in a strong fluorescent signal. The reaction was a one-step method with a shortened time of 1 h and a constant temperature of 37 °C, without the addition of any protease. It also sensitively distinguished telomerase activity in various cell lines. The T-DNA nanomachine offered a detection limit of 12 HeLa cells µL-1, 9 SK-Hep-1 cells µL-1 and 3 HuH-7 cells µL-1 with a linear correlation detection range of 0.39 × 102-6.25 × 102 HeLa cells µL-1 for telomerase activity. SIGNIFICANCE: In conclusion, our study demonstrated that the triggered-DNA nanomachine fulfills the requirements for rapid detection of telomerase activity in one-step under isothermal and enzyme-free conditions with excellent specificity, and its simple and stable structure makes it ideal for complex systems. These findings indicated the application prospect of DNA nanomachines in clinical diagnostics and provided new insights into the field of DNA nanomachine-based bioanalysis.


Asunto(s)
Técnicas Biosensibles , ADN Catalítico , Telomerasa , Humanos , Células HeLa , Telomerasa/análisis , ADN/química , ADN Catalítico/química , Técnicas Biosensibles/métodos , Límite de Detección
6.
Small ; 20(30): e2308562, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38441369

RESUMEN

Diagnosis and treatment of tumor especially drug-resistant tumor remains a huge challenge, which requires intelligent nanomedicines with low toxic side effects and high efficacy. Herein, deformable smart DNA nanomachines are developed for synergistic intracellular cancer-related miRNAs imaging and chemo-gene therapy of drug-resistant tumors. The tetrahedral DNA framework (MA-TDNA) with fluorescence quenched component and five antennas is self-assembled first, and then DOX molecules are loaded on the MA-TDNAs followed by linking MUC1-aptamer and Mcl-1 siRNA to the antennas of MA-TDNA, so that the apt-MA-TDNA@DOX-siRNA (DNA nanomachines) is constructed. The DNA nanomachine can respond to two tumor-related miRNAs in vitro and in vivo, which can undergo intelligent miRNA-triggered opening of the framework, resulting in the "turn on" of the fluorescence for sensitively and specifically sensing intracellular miRNAs. Meanwhile, both miRNA-responded rapid release and pH-responded release of DOX are achieved for chemotherapy of tumor. In addition, the gene therapy of the DNA nanomachines is achieved due to the miRNA-specific capture and the RNase H triggered release of Mcl-1 siRNA. The DNA nanomachines intergrading both tumor imaging and chemo-gene therapy in single nanostructures realized efficient tumor-targeted, image-guided, and microenvironment-responsive tumor diagnosis and treatment, which provides a synergetic antitumor effect on drug-resistant tumor.


Asunto(s)
ADN , Doxorrubicina , Resistencia a Antineoplásicos , Terapia Genética , MicroARNs , MicroARNs/genética , Humanos , Resistencia a Antineoplásicos/efectos de los fármacos , Doxorrubicina/farmacología , Doxorrubicina/química , Doxorrubicina/uso terapéutico , Terapia Genética/métodos , ADN/química , Animales , Neoplasias/terapia , Neoplasias/diagnóstico por imagen , Neoplasias/genética , ARN Interferente Pequeño , Línea Celular Tumoral , Espacio Intracelular/metabolismo
7.
Biosens Bioelectron ; 252: 116149, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38394701

RESUMEN

The microRNA-21 is closely related to chromatin remodeling and epigenetic regulation. In this work, an efficient double-response 3D DNA nanomachine (DRDN) was assembled by co-immobilizing two different lengths of hairpin DNA on the surface of gold nanoparticles (AuNPs) to capture microRNA-21 (miRNA-21), recycle miRNA-21, and trigger hybridization chain reactions (HCR). This work reports the fabrication of a laser-scribed graphene (LSG) electrode with excellent flexibility and electrical conductivity by laser-scribing commercial polyimide films (PI). The as-proposed self-powered biosensing platform presents significantly increased instantaneous current to in real-time monitor miRNA-21 by a capacitor. The biosensing platform exhibited highly sensitive detection of miRNA-21 with a detection limit of 0.142 fM in the range of 0.5 fM to 1 × 104 fM, and demonstrated high efficiency in the analysis of the tumor markers.


Asunto(s)
Técnicas Biosensibles , Nanopartículas del Metal , MicroARNs , MicroARNs/genética , MicroARNs/análisis , Oro , Epigénesis Genética , Técnicas Electroquímicas , ADN/genética , Límite de Detección
8.
J Biochem ; 176(1): 11-21, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38366640

RESUMEN

The small GTPase Ras plays an important role in intracellular signal transduction and functions as a molecular switch. In this study, we used a photoresponsive protein as the molecular regulatory device to photoregulate Ras GTPase activity. Photo zipper (PZ), a variant of the photoresponsive protein Aureochrome1 developed by Hisatomi et al. was incorporated into the C-terminus of Ras as a fusion protein. The three constructs of the Ras-PZ fusion protein had spacers of different lengths between Ras and PZ. They were designed using an Escherichia coli expression system. The Ras-PZ fusion proteins exhibited photoisomerization upon blue light irradiation and in the dark. Ras-PZ dimerized upon light irradiation. Moreover, Ras GTPase activity, which is accelerated by the Ras regulators guanine nucleotide exchange factors and GTPase-activating proteins, is controlled by photoisomerization. It has been suggested that light-responsive proteins are applicable to the photoswitching of the enzymatic activity of small GTPases as photoregulatory molecular devices.


Asunto(s)
Proteínas ras , Proteínas ras/metabolismo , Proteínas ras/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/química , Luz , Escherichia coli/metabolismo , Escherichia coli/genética , Procesos Fotoquímicos
9.
ACS Appl Bio Mater ; 7(2): 1073-1080, 2024 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-38215043

RESUMEN

Herein, we reported an innovative thermodynamic allosteric switch-actuated 3D DNA nanomachine for selective, sensitive, and accurate electrochemical (EC)/fluorescent (FL) dual-mode biosensing of a microphthalmia-associated transcription factor (MITF). The thermodynamic allosteric switch was ingeniously customized as a hairpin probe (HP) that was in dynamic equilibrium but rapidly interconverting conformations. At the "inactive state", the MITF-binding region and the switch part were "sequestered". Upon the introduction of MITF, an MITF-HP complex promptly formed, and the equilibrium of HP thermodynamically inclined from the "inactive state" toward the "active state" conformation. Immediately, the exposed switch on HP effectively actuated the 3D DNA nanomachine and synchronously produced the restriction site for Nb.BbvCI nicking endonuclease. After the autonomous conveying of the 3D DNA nanomachine by means of the high-efficiency circularly nicking endonuclease signal amplification (NESA), not only was MB-S1 in the supernatant used for FL measurements but also MB-SP/MNs/S2 in the precipitate was adapted for EC analysis, significantly improving the utilization of output products derived from the 3D DNA nanomachine. Accordingly, benefiting from the efficient DNA nanomachine signal amplification manner and the self-calibration function of a dual-mode bioassay, the constructed biosensor exhibits superior sensitivity and accuracy for MITF determination.


Asunto(s)
Técnicas Biosensibles , Factores de Transcripción , Factores de Transcripción/genética , ADN/química , Regulación de la Expresión Génica , Endonucleasas/genética
10.
Proc Natl Acad Sci U S A ; 121(4): e2317452121, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38236729

RESUMEN

Bacterial flagella and type IV pili (TFP) are surface appendages that enable motility and mechanosensing through distinct mechanisms. These structures were previously thought to have no components in common. Here, we report that TFP and some flagella share proteins PilO, PilN, and PilM, which we identified as part of the Helicobacter pylori flagellar motor. H. pylori mutants lacking PilO or PilN migrated better than wild type in semisolid agar because they continued swimming rather than aggregated into microcolonies, mimicking the TFP-regulated surface response. Like their TFP homologs, flagellar PilO/PilN heterodimers formed a peripheral cage that encircled the flagellar motor. These results indicate that PilO and PilN act similarly in flagella and TFP by differentially regulating motility and microcolony formation when bacteria encounter surfaces.


Asunto(s)
Proteínas Bacterianas , Fimbrias Bacterianas , Proteínas Bacterianas/metabolismo , Fimbrias Bacterianas/genética , Fimbrias Bacterianas/metabolismo , Bacterias , Flagelos/fisiología
11.
Talanta ; 269: 125478, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38039675

RESUMEN

Rapid and accurate detection of the hepatitis C virus (HCV) is essential for early diagnosis and prevention of virus transmission. This study presents a novel approach that combines the three-dimensional (3D)-DNA walking nanomachine with catalytic hairpin assembly (CHA) and copper nanoclusters (CuNCs). By integrating CHA with the 3D DNA walking nanomachine, efficient target amplification on 3D surfaces was achieved, leading to improved reaction speed and detection performance. Terminal deoxynucleotidyl transferase (TdT) was utilized to generate T-rich DNA sequences. These sequences served as templates for the formation of CuNCs, which functioned as the readout signal. The optimized 3D-DNA walking nanomachine exhibited excellent sensitivity in detecting HCV, with a detection limit of 42.4 pM and a linear range of 100 pM to 2 nM. The biosensor demonstrated excellent selectivity and reproducibility, with a recovery rate ranging from 94% to 108% for the detection of real samples. This design holds great potential for sensitive, label-free, and reliable detection of HCV in clinical settings. Furthermore, the versatility of this approach allows for the customization of target sequences, thereby facilitating the detection of various nucleic acid targets. Therefore, this method has the potential to advance personalized medicine, disease management, and genetic analysis in the field of molecular diagnosis.


Asunto(s)
Técnicas Biosensibles , ADN Catalítico , Hepatitis C , MicroARNs , Humanos , Hepacivirus/genética , Cobre , Reproducibilidad de los Resultados , Límite de Detección , ADN , Técnicas Biosensibles/métodos , ADN Nucleotidilexotransferasa , Hepatitis C/diagnóstico , MicroARNs/análisis
12.
ACS Appl Mater Interfaces ; 16(1): 281-291, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38156775

RESUMEN

Intelligent DNA nanomachines are powerful and versatile molecular tools for bioimaging and biodiagnostic applications; however, they are generally constrained by complicated synthetic processes and poor reaction efficiencies. In this study, we developed a simple and efficient molecular machine by coupling a self-powered rolling motor with a lipidic nanoflare (termed RMNF), enabling high-contrast, robust, and rapid probing of cancer-associated microRNA (miRNA) in serum and living cells. The lipidic nanoflare is a cholesterol-based lipidic micelle decorated with hairpin-shaped tracks that can be facilely synthesized by stirring in buffered solution, whereas the 3D rolling motor (3D RM) is a rigidified tetrahedral DNA scaffold equipped with four single-stranded "legs" each silenced by a locking strand. Once exposed to the target miRNA, the 3D RM can be activated, followed by self-powered precession based on catalyzed hairpin assembly (CHA) and lighting up of the lipidic nanoflare. Notably, the multivalent 3D RM that moves using four DNA legs, which allows the motor to continuously and acceleratedly interreact with DNA tracks rather than dissociate from the surface of the nanoflare, yielded a limit of detection (LOD) of 500 fM at 37 °C within 1.5 h. Through the nick-hidden and rigidified structure design, RMNF exhibits high biostability and a low false-positive signal under complex physiological settings. The final application of RMNF for miRNA detection in clinical samples and living cells demonstrates its considerable potential for biomedical imaging and clinical diagnosis.


Asunto(s)
Técnicas Biosensibles , MicroARNs , Humanos , MicroARNs/genética , ADN/química , Células MCF-7 , Límite de Detección , Técnicas Biosensibles/métodos
13.
Artículo en Inglés | MEDLINE | ID: mdl-38044636

RESUMEN

DNA nanomachines could initiate the cascade reaction in an autonomous mode under the drive of triggers, which achieve the signal amplification for the bioimaging of intracellular biomarkers. Compared with the "always-on" nanomachine that possibly produces false-positive signals, a controllable nanomachine with the on-site activation could be better for accurate tumor imaging and precise tumor therapy. Till now, the endogenous and exogenous triggers have been developed to design the controllable nanosensors. However, their combinations to develop feasible DNA nanomachines have been rarely studied. Herein, we constructed a near-infrared (NIR)-light-controlled DNA nanomachine that was first activated by the NIR light and then induced a target-triggered amplification process under the drive of an endogenous stimulus. Owing to adenosine-5'-triphosphate (ATP) having much higher concentration in cancer cells than that in healthy cells and the extracellular fluid, the obtained DNA nanomachine was selectively activated in cancer cells with inhibited interference signals from the surrounding healthy tissues. With obvious advantages including the exogenous NIR light initiation, the selective activation by the target microRNA, and the sensitive acceleration by the ATP-induced strand recycling reaction, the constructed nanomachine could be used to image the intracellular microRNA with increased sensitivity. Besides, after modifying the DNA sequence with the photosensitizer molecules, the obtained nanomachine could perform the selective photodynamic therapy on the tumor sections with the outstandingly decreased side effects. Thus, we hope the designed nanomachine could provide some important hints to design feasible nanomachines for accurate tumor diagnosis and precise tumor therapy.

14.
Angew Chem Int Ed Engl ; 62(50): e202312665, 2023 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-37903741

RESUMEN

Aberrant expressions of biomolecules occur much earlier than tumor visualized size and morphology change, but their common measurement strategies such as biopsy suffer from invasive sampling process. In vivo imaging of slight biomolecule expression difference is urgently needed for early cancer detection. Fluorescence of rare earth nanoparticles (RENPs) in second near-infrared (NIR-II) region makes them appropriate tool for in vivo imaging. However, the incapacity to couple with signal amplification strategies, especially programmable signal amplification strategies, limited their application in lowly expressed biomarkers imaging. Here we develop a 980/808 nm NIR programmed in vivo microRNAs (miRNAs) magnifier by conjugating activatable DNAzyme walker set to RENPs, which achieves more effective NIR-II imaging of early stage tumor than size monitoring imaging technique. Dye FD1080 (FD1080) modified substrate DNA quenches NIR-II downconversion emission of RENPs under 808 nm excitation. The miRNA recognition region in DNAzyme walker is sealed by a photo-cleavable strand to avoid "false positive" signal in systemic circulation. Upconversion emission of RENPs under 980 nm irradiation activates DNAzyme walker for miRNA recognition and amplifies NIR-II fluorescence recovery of RENPs via DNAzyme catalytic reaction to achieve in vivo miRNA imaging. This strategy demonstrates good application potential in the field of early cancer detection.


Asunto(s)
ADN Catalítico , Metales de Tierras Raras , MicroARNs , Neoplasias , Humanos , Metales de Tierras Raras/química , Neoplasias/diagnóstico por imagen , Neoplasias/patología , Espectroscopía Infrarroja Corta/métodos
15.
Biosens Bioelectron ; 241: 115671, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37714060

RESUMEN

As a unique class of dynamic nanostructures, biomimetic DNA walking machines that exhibit geometrical complexity and nanometre precision have gained great success in photoelectrochemical (PEC) bioanalysis. Despite certain achievements, the slow reaction kinetics and low processivity severely restrict the amplification efficiency of the DNA walker-mediated biosensors. Herein, by taking advantage of efficient DNA rolling machines, a three-dimensional (3D) DNA nanomachine-mediated paper-based PEC device for speedy ultrasensitive detection of miR-486-5p was successfully constructed. To achieve it, a novel In2S3/SnS2 sensitized heterojunction was firstly in-situ grown on the Au-modified paper fibers and implemented as the photoanode with effective separation of photogenerated carriers to achieve an enhanced initial photocurrent. Subsequently, the copper hexacyanoferrate(II)-modified CuO nanosphere was introduced as a multifunctional signal regulator via the competitive capture of electron donors and photon energy with the photoelectric layer for efficiently quenching the PEC signal. With the introduction of targets, the DNAzyme-driven DNA nanomachine with editable motion modes was gradually activated and it could continuously cleave the tracks DNA labeled quenching probes, finally achieving the recovery of PEC signal. As a proof of concept, the elaborated paper-based PEC device presented a wide linear range from 0.1 fM to 100 pM and a detection limit of 35 aM for miR-486-5p bioassay. This work provides an innovative insight to the exploitation of DNA nanobiotechnology and nucleic acid signal amplification strategy.

16.
Int J Mol Sci ; 24(15)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37569700

RESUMEN

The mechanical performances of the vertebrate skeletal muscle during isometric and isotonic contractions are interfaced with the corresponding energy consumptions to define the coupling between mechanical and biochemical steps in the myosin-actin energy transduction cycle. The analysis is extended to a simplified synthetic nanomachine in which eight HMM molecules purified from fast mammalian skeletal muscle are brought to interact with an actin filament in the presence of 2 mM ATP, to assess the emergent properties of a minimum number of motors working in ensemble without the effects of both the higher hierarchical levels of striated muscle organization and other sarcomeric, regulatory and cytoskeleton proteins. A three-state model of myosin-actin interaction is able to predict the known relationships between energetics and transient and steady-state mechanical properties of fast skeletal muscle either in vivo or in vitro only under the assumption that during shortening a myosin motor can interact with two actin sites during one ATP hydrolysis cycle. Implementation of the molecular details of the model should be achieved by exploiting kinetic and structural constraints present in the transients elicited by stepwise perturbations in length or force superimposed on the isometric contraction.

17.
ACS Nano ; 17(17): 16553-16564, 2023 09 12.
Artículo en Inglés | MEDLINE | ID: mdl-37527488

RESUMEN

Gastric cancer (GC) is one of the most common tumors worldwide and is the leading cause of tumor-related mortality. Traditional biomarkers and screening methods cannot meet the clinical demands. There is an urgent need for highly sensitive diagnostic markers as well as accurate quantification methods for early gastric cancer (EGC) screening. Here a dual-target cooperatively responsive fluorescent nanomachine by the innovative application of two targets─responsive strand migration system with a single-amplification-cycle element was developed for the simultaneous detection of GC biomarkers miR-5585-5p and PLS3 mRNA, which were selected by next-generation sequencing and RT-qPCR. It was also an RNA extraction-free, PCR-free, and nonenzymatic biosensor to achieve tumor cell imaging and serum diagnosis. Requiring only a 20 µL serum sample and 20 min incubation time, the nanomachine achieved an ultrasensitive detection limit of fM level with a broad linear range from fM to nM. More importantly, a higher AUC value (0.884) compared to the clinically used biomarker CA 72-4 was obtained by the nanomachine to distinguish GC patients successfully. Notably, for the key concerns of diagnosis of EGC patients, the nanomachine also achieved a satisfactory AUC value of 0.859. Taken together, this work has screened and obtained multiple biomarkers and developed a fluorescent nanomachine for combination diagnosis of GC, providing an ingenious design of a functionalized DNA nanomachine and a feasible strategy for the transformation of serum biomarkers into clinical diagnosis.


Asunto(s)
Técnicas Biosensibles , MicroARNs , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/diagnóstico por imagen , ADN/genética , Colorantes , Biomarcadores de Tumor , Técnicas Biosensibles/métodos , MicroARNs/genética
18.
Biosens Bioelectron ; 237: 115517, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37459686

RESUMEN

The working efficiency of traditional 3D DNA nanomachines is extremely restricted due to the complex DNA components modified on nanoparticles in the same spatial height. Herein, an ultrafast dual-layer 3D DNA nanomachine (UDDNM) based on catalytic hairpin assembly (CHA) was developed by assembling two different lengths of hairpin DNA on the surface of gold nanoparticles, the long hairpin 1 (H1), to capture the trigger, and the short hairpin 2 (H2), as the signal probe, to recycle the trigger. Compared to the traditional single-layer 3D DNA nanomachine, the dual-layer 3D DNA nanostructure greatly enhances the effective collision between trigger and targeted DNA probe, H1, since the H1 located in outer layer would react with the trigger, inhibiting the invalid collision between the trigger and residual DNA component, H2, and remarkably decreasing the steric hindrance associated with the nucleic acids layer around the nanoparticles. Especially, when the distance of two layers was fixed at 3 nm, the corresponding UDDNM could accomplish the overall reaction only in 3 min with a dramatically high initial rate of up to 5.93 × 10-7 M s-1, which was at least 5-fold beyond that of the typical single-layer 3D DNA nanomachines. As a proof of concept, the described UDDNM was successfully applied in ultrasensitive fluorescence detection and sensitive intracellular imaging of miRNA-21. Consequently, our strategy, based on the creation of dual-layer 3D DNA nanostructure, may create a new approach to designing the next generation of DNA nanomachine and has enormous potential for applications in bio-analysis, logic gate operations, and clinical diagnoses.


Asunto(s)
Técnicas Biosensibles , ADN Catalítico , Nanopartículas del Metal , MicroARNs , Nanoestructuras , MicroARNs/análisis , Oro/química , Nanopartículas del Metal/química , Técnicas Biosensibles/métodos , ADN/química , Nanoestructuras/química , Límite de Detección , ADN Catalítico/química
19.
Talanta ; 265: 124908, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37442003

RESUMEN

Realizing the simultaneous speedy detection of multiple mycotoxins in contaminated food and feed is of great practical importance in the domain of food manufacturing and security. Herein, a fluorescent aptamer sensor based on self-assembled DNA double-crossover was developed and used for effective simultaneous quantitative detection of aflatoxins M1 and B1 by fluorescence resonance energy transfer (FRET). Fluorescent dye-modified aflatoxin M1 and B1 aptamers are selected as recognition elements and signal probes, and DNA double crosses are consistently locked by the aflatoxin aptamers, which results in a "turn-off" of the fluorescent signal. In the presence of AFM1 and AFB1, the aptamer sequences are more inclined to form Apt-AFM1 and Apt-AFB1 complexes, and the fluorescent probes are released from the DNA double-crossing platform, leading to an enhanced fluorescent signal (Cy3: 568 nm; Cy5: 660 nm). Under the optimal conditions, the signal response of the constructed fluorescent aptamer sensor showed good linearity with the logarithm of AFM1 and AFB1 concentrations, with detection limits of 6.24 pg/mL and 9.0 pg/mL, and a wide linear range of 0.01-200 ng/mL and 0.01-150 ng/mL, respectively. In addition, the effect of potential interfering substances in real samples was analyzed, and the aptasensor presented a good interference immunity. Moreover, by modifying and designing aptamer probes, the sensor can be applied to high-throughput simultaneous screening of other analytes, providing a new approach for the development of fluorescent aptamer sensors.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Aflatoxina B1/análisis , Aflatoxina M1/análisis , ADN , Colorantes Fluorescentes , Límite de Detección , Técnicas Biosensibles/métodos
20.
Bioessays ; 45(9): e2300078, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37329195

RESUMEN

The type III secretion system (T3SS) is a specialized nanomachine that enables bacteria to secrete proteins in a specific order and directly deliver a specific set of them, collectively known as effectors, into eukaryotic organisms. The core structure of the T3SS is a syringe-like apparatus composed of multiple building blocks, including both membrane-associated and soluble proteins. The cytosolic components organize together in a chamber-like structure known as the sorting platform (SP), responsible for recruiting, sorting, and initiating the substrates destined to engage this secretion pathway. In this article, we provide an overview of recent findings on the SP's structure and function, with a particular focus on its assembly pathway. Furthermore, we discuss the molecular mechanisms behind the recruitment and hierarchical sorting of substrates by this cytosolic complex. Overall, the T3SS is a highly specialized and complex system that requires precise coordination to function properly. A deeper understanding of how the SP orchestrates T3S could enhance our comprehension of this complex nanomachine, which is central to the host-pathogen interface, and could aid in the development of novel strategies to fight bacterial infections.


Asunto(s)
Proteínas Bacterianas , Vías Secretoras , Proteínas Bacterianas/metabolismo , Transporte de Proteínas , Sistemas de Secreción Tipo III/química , Sistemas de Secreción Tipo III/metabolismo , Citosol/metabolismo
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