Dual-mode Strategy Research Articles

Dual-modal overcoming of physical barriers for improved photodynamic cancer therapy via soft organosilica nanocapsules

Amidst the burgeoning field of cancer nanomedicine, dense extracellular matrices and anomalous vascular structures in the tumor microenvironment (TME) present substantial physical barriers to effective therapeutic delivery. These physical barriers hinder the optimal bioavailability of nanomedicine. Here, we propose a pioneering dual-modal strategy for overcoming physical barriers via soft organosilica nanocapsules (SMONs). Hyaluronidase-modified flexible spheres work by degrading the extracellular matrix and utilizing their flexible characteristics to enhance penetration into deeper layers. Compared with their stiff counterparts, the SMONs show diminished Young’s modulus, then the inherent softness of the SMONs confers distinct advantages, and significantly augmented cellular internalization within 4T1 cells, leading to an amplified in vitro photodynamic therapeutic effect. Furthermore, hyaluronidase-functionalized SMONs (SMONs-HAase) exhibit enhanced tumor penetration in 3D spheroids. Post incorporation of the photosensitizer chlorin e6, when administered intravenously, these soft organosilica nanocapsules amplify the efficacy of photodynamic therapy. In addition, RNA-seq analysis of SMONs-HAase-Ce6 shows it alters gene expression, degrading the extracellular matrix and impairing mitochondrial function. To sum up, this work elucidates the potential of a dual-modal strategy, highlighting the promise of SMONs in overcoming TME physical barriers and optimizing therapeutic outcomes.Graphical abstract

Dual-mode strategy for glyphosate detection: Leveraging competitive interaction with iron and zinc-organic frameworks

The extensive use of glyphosate poses a potential threat to food safety, human health, and the ecological environment. Hence, detecting glyphosate residues in food is of great significance for food safety. In this work, the synthesis of zinc-organic frameworks (Zn-MOFs) was achieved through the coordination of Zn2+ with the 2,5-dihydroxyterephthalic acid (DOBDC) ligand. Upon excitation at 350 nm, these Zn-MOFs exhibited robust fluorescence emission at 533 nm. However, upon the addition of iron ions, the Zn-MOFs structure disintegrated, forming a blue Fe-DOBDC complex, resulting in fluorescence quenching. In the presence of glyphosate, the iron ions were chelated by glyphosate, causing the system to lighten in color and restore fluorescence. Further, the mechanism of this strategy was investigated, which was achieved by utilizing the competitive interaction of glyphosate and Zn-MOFs for iron ions. The binding stoichiometry and binding constant of glyphosate:Fe3+ are 1:1 and 7.59 × 103 M−1 using the Job's plot and Benesi-Hildebrand equation, respectively. To enhance glyphosate detection, this study introduced an ingenious dual-mode strategy. By analyzing the colorimetric and fluorescence changes before and after glyphosate addition, we can accurately determine its concentration in the system. The combined colorimetric and fluorescent modalities offer improved reliability and applicability, boasting simplicity, rapidity, and cost-effectiveness. This innovative method is anticipated to find widespread applications and offers novel perspectives on pesticide detection platforms based on ligand competition effects.

Near-infrared modulated photothermal/nanozymatic dual-modal strategy for combating cancer via molybdenum selenide nanourchins

BackgroundBreast cancer, a major health concern globally, often faces challenges in the non-invasive elimination of cancer cells. This has prompted researchers to explore alternative strategies, such as photothermal therapy (PTT), which takes advantage of the location of breast cancer lesions. Additionally, the tumor microenvironment with high hydrogen peroxide (H2O2) provides a key prerequisite for treating tumors with nanozymes, especially those with peroxidase (POD)-like activity. However, the overexpression of TrxR1, which maintains redox homeostasis in tumor cells, limits reactive oxygen species (ROS)-based cytotoxic therapy. This study aims to present molybdenum selenide nano urchins (MoSe2 NUs) with excellent photothermal conversion efficiency, POD-like activity and selective inhibition of TrxR1 to achieve photothermal enhanced nanocatalytic therapy for combating breast cancer.MethodsThe characterization of MoSe2 NUs synthesized by the hydrothermal method was identified by TEM, XRD, Zeta potential and DLS. Whether MoSe2 NUs in conjunction with NIR possessed POD-like activities or not was identified via a TMB colorimetric method. The photothermal characteristics of MoSe2 NUs excited by near-infrared were recorded by an infrared thermal imaging camera. The antitumor effect of MoSe2 NUs was detected by cell death staining, apoptosis assay and animal experiments. TrxR1 and apoptosis-related protein expression were identified by Western blot and Immunohistochemistry.ResultsMoSe2 NUs possessed excellent photothermal conversion efficiency, peroxidase (POD)-like activity, and selective inhibition of TrxR1. Furthermore, the photothermal effect of MoSe2 NUs can enhance their POD-like activity, allowing for accurate cancer treatment under near-infrared (NIR) light. MoSe2 NUs plus NIR and MoSe2 NUs alone exhibited in vivo tumor inhibition rates of 69.7% and 35.1%, respectively. Mechanistically, NIR-regulated MoSe2 NUs induced potent apoptosis of cancer cells by downregulating the TrxR1 and elevating intracellular ROS, thereby leading to caspase-3 cleavage.ConclusionsThis study demonstrated that MoSe2 NUs under NIR irradiation can precisely and efficiently treat breast cancer and have great potential for clinical application.Graphical

A dual-mode strategy for early detection of sugarcane pokkah boeng disease pathogen: A portable sensing device based on Cross-N DNA framework and MoS2@GDY

Sucrose, a common sugar primarily derived from sugarcane, is a crucial national strategic resource. However, its yield is significantly affected by various serious diseases, with pokkah boeng disease being one of the most damaging. Therefore, developing a sensitive method for the accurate detection of the pokkah boeng disease pathogen is crucial for ensuring the safety of sugar. This work presents a portable dual-modal detection device, assisted by a smartphone, which is based on MoS2@GDY, Mn3O4@Au nanomenzyme, cross-N DNA framework and Exo III exonuclease-assisted CHA signal amplification technology. The cross-N DNA framework provides many binding sites and is not restricted by AuNPs scattering positions, enhancing the signal output strength of the sensor. Additionally, the detection system incorporates a high-power-density capacitor to further amplify the electrochemical detection signal, increasing sensitivity by 9.1 times. Moreover, the use of electrochemical and colorimetric dual-mode detection effectively avoids mutual interference, reducing the likelihood of false positives from a single signal. Under optimized conditions, the proposed method has a linear range of 0.0001–10,000 pM, and with a detection limit of 6.1 aM (S/N=3). This high-sensitivity, high-reliability portable sensing method shows significant potential for the early detection and real-time on-site monitoring of the pokkah boeng disease pathogen.

Resilient Self-Triggered Model Predictive Control of Cyber-Physical Systems Under Two-Channel False Data Injection Attacks

Abstract This paper presents a novel resilient self-triggered model predictive control (ST-MPC) method to alleviate potential threats of false data injection (FDI) attacks on cyber-physical systems (CPSs). First, considering that the data transmitted via the sensor-to-controller (S–C) and controller-to-actuator (C–A) channels in CPS may be tampered with by FDI attacks, a novel input reconstruction strategy combined with the ST-MPC mechanism is proposed to alleviate the threats of FDI attacks while reducing the computational and communication resources, in which key optimal control signals are selected and protected based on systematic performance inequalities. Correspondingly, a resilient ST-MPC algorithm combined with the dual-mode strategy is further proposed. Moreover, the iterative feasibility and the closed-loop stability are strictly demonstrated. Finally, the effectiveness of the proposed strategy is verified via a simulation study.

Fluorescent and colorimetric dual-mode detection of Cu2+ based on carbon dots.

A fluorescent and colorimetric dual-mode strategy based on carbon dots (CDs) was rationally designed for sensitive determination of Cu2+. Green fluorescent CDs with high absolute quantum yield of 72.9% were synthesized by facile one-step hydrothermal treatment of triethylenetetramine and Rose Bengal. Cu2+ could trigger the oxidative and chromogenic reaction of p-phenylenediamine (PPD) to generate chromogenic PPDox, accompanied by the fluorescence quenching of the CDs. The quenching mechanism was identified as the inner filter effect between PPDox and CDs. Therefore, a colorimetric/fluorescent dual-mode detection method for Cu2+ recognition was constructed. The limits of detection for Cu2+ were 4.14μM and 1.28μM for colorimetric and fluorescent mode, respectively. In addition, this method had achieved satisfactory results in the detection of Cu2+ in real serum samples.

Dual-mode detection of glucose based on pistol-like DNAzyme-mediated exonuclease-assisted signal cycle.

Detecting glucose accurately and sensitively from clinical samples like tears and saliva is still difficult. We have created a sensor that can detect glucose with high sensitivity and accuracy by combining the use of glucose oxidase (GOx) to catalyze glucose, a pistol-like DNAzyme (PLDz) to transform the signal, gold nanoparticles (AuNPs) to enhance the optical properties and the exonuclease-III (Exo-III) to amplify the signal. As a result, the proposed method exhibits a low detection limit of 7.5pM and a wide detection range covering seven orders of magnitude. The suggested dual-mode strategy provides a sensitive, precise and specific detection method for glucose. Another advantage is that the dual-mode technique significantly improves the precision and consistency of the measurements, demonstrating its immense potential for use in biomedical research and clinical diagnostics.

An ultrasensitive electrochemical/colorimetric dual-mode self-powered biosensing platform for lung cancer marker detection by multiple-signal amplification strategy

BackgroundIn recent years, miRNAs have emerged as potentially valuable tumor markers, and their sensitive and accurate detection is crucial for early screening and diagnosis of tumors. However, the analysis of miRNAs faces significant challenges due to their short sequence, susceptibility to degradation, high similarity, low expression level in cells, and stringent requirements for in vitro research environments. Therefore, the development of sensitive and efficient new methods for the detection of tumor markers is crucial for the early intervention of related tumors. ResultsAn ultrasensitive electrochemical/colorimetric dual-mode self-powered biosensor platform is established to detect microRNA-21 (miR-21) via a multi-signal amplification strategy. Gold nanoparticles (AuNPs) and VS4 nanosheets self-assembled 3D nanorods (VS4-Ns-Nrs) are prepared for constructing a superior performance enzyme biofuel cell (EBFC). The double-signal amplification strategy of Y-shaped DNA nanostructure and catalytic hairpin assembly (CHA) is adopted to further improve enhance the strength and specificity of the output signal. In addition, a capacitor is matched with EBFC to generate an instantaneous current that is amplified several times, and the output detection signal is improved once more. At the same time, electrochemical and colorimetric methods are used for dual-mode strategy to achieve the accuracy of detection. The linear range of detection is from 0.001 pg/mL to 1000 pg/mL, with a relatively low limit of detection (LOD) of 0.16 fg/mL (S/N = 3). SignificanceThe established method enables accurate and sensitive detection of markers in patients with lung cancer, providing technical support and data reference for precise identification. It is anticipated to offer a sensitive and practical new technology and approach for early diagnosis, clinical treatment, and drug screening of cancer and other related major diseases.

Dual-mode nanoprobe strategy integrating ultrasound and near-infrared light for targeted and synergistic arterial thrombolysis

Efficient thrombolysis in time is crucial for prognostic improvement of patients with acute arterial thromboembolic disease, while limitations and complications still exist in conventional thrombolytic treatment methods. Herein, our study sought to investigate a novel dual-mode strategy that integrated ultrasound (US) and near-infrared light (NIR) with establishment of hollow mesoporous silica nanoprobe (HMSN) which contains Arginine-glycine-aspartate (RGD) peptide (thrombus targeting), perfluoropentane (PFP) (thrombolysis with phase-change and stable cavitation) and indocyanine green (ICG) (thrombolysis with photothermal conversion). HMSN is used as the carrier, the surface is coupled with targeted RGD to achieve high targeting and permeability of thrombus, PFP and ICG are loaded to achieve the collaborative diagnosis and treatment of thrombus by US and NIR, so as to provide a new strategy for the integration of diagnosis and treatment of arterial thrombus. From the in vitro and in vivo evaluation, RGD/ICG/PFP@HMSN can aggregate and penetrate at the site of thrombus, and finally establish the dual-mode directional development and thrombolytic treatment under the synergistic effect of US and NIR, providing strong technical support for the accurate diagnosis and treatment of arterial thrombosis.Graphical

An Adaptive Dual-Mode Task-Oriented Resource Management Strategy for GEO Relay Systems

With the fierce global competition on satellite networks, the building of satellite constellations grows explosively. Sharply increasing on-orbit data will face the challenge of satellite-ground data transmission. GEO satellites become the top choice for satellite data relay due to their stable satellite-ground link. Most existing spectrum resource management for GEO relays is equipment-oriented and benefit priority, which may lead to a waste of spectrum resources. In this paper, we propose a real-time task-oriented resource allocation strategy for GEO relay systems. We model the spectrum allocation problem as a distributed non-cooperative Stackelberg game process. We prove that when both sides of the game pursue the maximization of personal revenue, the system will enter a Nash equilibrium state, whereas spectrum resources are not fully used. Based on the maximization of individual utilities (U-prior) and spectrum utilization (S-prior) methods, we design an adaptive dual-mode pricing mode to maximize the spectrum resources within a certain loss of revenue. The simulation results show that the S-prior and U-prior have better performance than the baseline method and existing optimization methods. Our proposed dual-mode strategy is making more throughputs and has less delay with little loss of utility values than that of individual utility maximization.

The chemostat reactor: A stability analysis and model predictive control

This contribution develops the model predictive control for an unstable chemostat reactor. Initially, we analyze the system’s model — a nonlinear first-order hyperbolic partial integro-differential equation (PIDE) — and carry the model linearization around an unstable operating condition. Employing the structure-preserving Cayley–Tustin transformation, we obtain a discrete-time model representation of the continuous model. Subsequently, we solve the operator Ricatti equations in the discrete-time setting to derive a full state feedback controller that stabilizes the closed-loop and design a Luenberger observer for state reconstruction given the system output measures. Finally, we formulate a dual-mode MPC ensuring constraint satisfaction and optimality, integrating the gain-based unconstrained full-state feedback optimal control obtained from the Ricatti equation. This dual-mode strategy describes an optimization problem where the predictive controller acts only if constraints become active within the control horizon. Simulation studies validate the controller performance, where the MPC only takes action if the constraints are predicted to be active within the control horizon while also guaranteeing closed-loop stabilization under only output feedback. This type of controller can be easily implemented with other control strategies and significantly decreases the computational costs of solving the optimal control problems when compared to other MPC approaches.

Self-validating photothermal and electrochemical dual-mode sensing based on Hg2+ etching Ti3C2 MXene

Mercury ions can cause serious damage to the ecological environment, and it is necessary to develop reliable and elegant mercury ion sensors. In this protocol, a label-free photothermal/electrochemical dual-mode strategy for Hg2+ is proposed based on delaminated Ti3C2 MXene nanosheets (DL-Ti3C2 MXene). Hg2+ exists in water in the form of HgCl2, Hg(OH)2, and HgClOH, and the electron-rich elements O and Cl can specifically bind to the positively charged DL-Ti3C2 MXene at the edge, and further oxidation-reduction reaction occurs to obtain TiO2/C and Hg2Cl2. In view of the reduction activity and the performance of photothermal conversion of DL-Ti3C2 MXene itself, the electrochemical and photothermal responses decrease with the increase of the logarithm of Hg2+ concentration. The corresponding linear ranges are 50 pmol L−1-500 nmol L−1 and 1 nmol L−1-50 μmol L−1, and their detection limits calculated at 3 S/N are 17.2 pmol L−1 and 0.43 nmol L−1, respectively. DL-Ti3C2 MXene has the characteristics of a wide range of raw materials, low cost, and easy preparation. In addition, the design takes full advantage of the properties of the material itself, avoids the complex assembly and detection process of conventional sensors, and enables high selectivity and sensitivity for mercury detection. In particular, the dual-mode sensing endows self-confirmation of mercury ion detection results, thereby improving the reliability of the sensor.

Detection of acetamiprid residues in vegetables by a self-enhanced bimetallic luminescent MOF-based electrochemiluminescence-electrochemistry dual-mode aptasensor

In this study, a dual-mode aptasensor based on the competition mechanism was constructed to detect acetamiprid (ACE) residues in vegetables. With 3,5-dicarboxyphenylboronic acid (5-bop) as a ligand, a bimetallic RuZn-based metal-organic framework (RuZn-MOF) was synthetized by applying a hydrothermal method to achieve efficient electrochemiluminescence (ECL) and electrochemistry (EC) dual-mode detection of ACE. Compared with the monometallic Zn-based metal-organic framework (Zn-MOF) of the same structure, the bimetallic RuZn-MOF exhibited a greater ability to transfer electrons due to the synergistic effect between different metal and the 5-bop ligand. Meanwhile, the complementary DNA (cDNA) probe for bonding the ACE aptamer was modified with ferrocene (Fc) and methylene blue (MB). When the target pesticide of ACE was present, ACE competed with the cDNA probe, so that the ECL achieved the "signal on" and the EC achieved the "signal off". ECL and EC detection being combined, the results showed that the two detection methods corroborated each other and worked synergistically, i.e., they effectively reduced the systematic errors and background signals, and improved the reliability of the detection. The linear ranges of the ECL and EC aptasensors were 1 pg/mL-1 μg/mL with the limit of detection (LOD) of 0.33 pg/mL, and 1 fg/mL-1 ng/mL with LOD of 0.33 fg/mL (S/N=3), respectively. The dual-mode strategy had good stability and specificity, providing some valuable support for the detection and analysis of other substances.

Fluorescence/electrochemical dual-mode strategy for Golgi protein 73 detection based on molybdenum disulfide/ferrocene/palladium nanoparticles and nitrogen-doped graphene quantum dots.

Golgi protein 73 (GP73) is a new serum marker associated with early diagnosis and postoperative assessment of hepatocellular carcinoma (HCC). Herein, an electrochemical/fluorescence dual-signal biosensor was designed for determination of GP73 based on molybdenum disulfide/ferrocene/palladium nanoparticles (MoS2-Fc-PdNPs) and nitrogen-doped graphene quantum dots (NGQDs). GP73 aptamer (Apt) was labeled with NGQDs to form the NGQDs-Apt fluorescence probe. MoS2-Fc-PdNPs served not onlyas the fluorescence quencher but also as electrochemical enhancer. The sensing platform (NGQDs-Apt/MoS2-Fc-PdNPs) was formed based on the fluorescence resonance energy transfer (FRET) mechanism. In the presence of GP73, the specific binding of NGQDs-Apt to GP73 interrupted FRET, restoring the fluorescence of NGQDs-Apt at λex/em = 348/438nm and enhancing the oxidation current of Fc in MoS2-Fc-PdNPs at 0.04V through differential pulse voltammetry (DPV). Under the optimal conditions, the DPV current change and fluorescence recovery have a good linear relationship with GP73 concentration from 1.00 to 10.0ng/mL. The calibration equation for the fluorescence mode was Y1 = (0.0213 ± 0.00127)X + (0.0641 ± 0.00448) and LOD was 0.812ng/mL (S/N = 3). The calibration equation of the electrochemical mode was Y2 = (3.41 ± 0.111)X + (1.62 ± 0.731), and LOD of 0.0425ng/mL (S/N = 3). The RSDs of fluorescence mode and electrochemical mode after serum detection were 1.62 to 5.21% and 0.180 to 6.62%, respectively. By combining the electrochemical and fluorescence assay, more comprehensive and valuable information for GP73 was provided. Such dual-mode detection platform shows excellent reproducibility, stability, and selectivity and has great application potential.

A dual-mode strategy for diacetyl detection based on colorimetry and surface-enhanced Raman scattering

Diacetyl is an important food additive with rich creamy flavor whose excessive intake may cause various diseases. Herein, for the first time, we designed a dual-mode method for diacetyl detection based on colorimetry and surface-enhanced Raman scattering (SERS) technology. Diacetyl exhibited excellent oxidase-like catalytic activity under light-mediated condition, facilitating the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue ox-TMB for colorimetric detection. Notably, diacetyl could control the oxidation process of TMB by simply adjusting light irradiation, unlike traditional enzymatic reactions that required terminators to stop the reaction. Interestingly, ox-TMB was an ideal Raman marker for SERS analysis. Then, a three-dimensional flower-like zinc oxide/silver (ZnO/Ag) for sensitive SERS detection was prepared, which exhibited outstanding SERS effect with a high enhancement factor of 1.89 × 108 due to effective charge transfer and synergistic effect between ZnO and Ag. Based on these, SERS method was constructed to indirectly detect diacetyl, which has not been reported due to low Raman activity of diacetyl. The linear ranges of colorimetry and SERS were 0.5–60 μM and 10−9-10−5 M respectively, with detection limits of 0.41 μM and 0.73 nM. Obviously, the dual-mode strategy combined the simplicity and practicality of colorimetry and the high sensitivity of SERS, offering great potential applications in practical samples.

Self-Assembled Integrated Nanozyme Cascade Biosensor with Dual Catalytic Activity for Portable Urease Analysis.

In this work, a novel nanozyme (Cu@Zr) with all-in-one dual enzyme and fluorescence properties is designed by simple self-assembly. A nanozyme cascade sensor with disodium phenyl phosphate (PPDS) as substrate was first established by exploiting the dual enzymatic activities of phosphatase and laccase. Specifically, phosphatase cleaves the P-O bond of PPDS to produce colorless phenol, which is then oxidized by laccase and complexed with the chromogenic agent 4-aminoantipyrine (4-AP) to produce red quinoneimine (QI). Strikingly, the NH3 produced by the urease hydrolysis of urea can interact with Cu@Zr, accelerating the electron transfer rate and ultimately leading to a significantly improved performance of the cascade reaction. Moreover, the fluorescence at 440 nm of Cu@Zr is further quenched by the inner filter effect (IFE) of QI. Thus, the colorimetric and fluorescence dual-mode strategy for sensitive urease analysis with LODs of 3.56 and 1.83 U/L was established by the proposed cascade sensor. Notably, a portable swab loaded with Cu@Zr was also prepared for in situ urease detection with the aid of a smartphone RGB readout. It also provides a potentially viable analytical avenue for environmental and biological analysis.

A dual-mode lateral flow immunoassay by ultrahigh signal-to background ratio SERS probes for nitrofurazone metabolites ultrasensitive detection

In this work, an ultra-sensitive lateral flow immunoassay (LFIA) with SERS/colorimetric dual signal mode was constructed for the detection of nitrofurazone metabolites, an antibiotic prohibited in animal-origin foods. Au@4-MBN@AgNRs nano-sandwich structural signal tag integrates the unique advantages of high signal-to-background ratio and anti-matrix interference through geometric control of SERS tag and nanoengineering adjustment of chemical composition. Under the optimal conditions, the detection limits of nitrofurazone metabolites by SERS/colorimetric dual-mode LFIA were 20 pg/mL (colorimetric mode) and 0.08 pg/mL (SERS mode). Excitingly, the vLOD of the colorimetric signal improved by a factor of 100 compared to Au NPs-based LFIA. In this study, the proposed dual-mode LFIA was successfully applied to the on-site real-time detection of honey, milk powder, and chicken. It is anticipated that with low background interference and anti-matrix interference output signal, our proposed dual-mode strategy can pave an innovative pathway for the fabrication of a powerful biosensor.

Homogeneous electroanalysis coupled with colorimetry dual-mode sensing of silver ion in water based on target-inhibited peroxidase activity of Pt@ZIF-8 nanozyme

Electrochemical sensing is the commonly used method for the detection of heavy metal silver ion (Ag+), while the conventional electrochemical sensors generally require the existence of electrode modifications and even electrodeposition step coupled with a single-mode readout. Herein, by preparing ZIF-8 organometallic frame load with platinum nanoparticles (Pt@ZIF-8) as nanozyme and o-phenylenediamine (OPD) as colorless substance, taking advantage of the superior peroxidase activity of Pt@ZIF-8 that can catalyze the oxidation of OPD to product electroactive/yellow 2,3-diaminophenazinc and the target-inhibited effect towards nanozyme activity from Ag+, a homogeneous electroanalysis coupled with colorimetry (HEA-CM) dual-mode sensing platform was designed for the first time to detect Ag+. Furthermore, the colorimetric images were converted on a smartphone to digital signals for the quantitative analysis. The designed strategy could offer multiple advantages such as electrodeposition-free, modification-free and dual channel readout. After investigating the sensing mechanism and experimental parameters, the analytical performance of the designed strategy was evaluated, obtaining extremely low detection limit (0.034 nM), reliable recovery rate (99.61 %-101.6 %) and wide linearity. This work offered an effective method for the simple, sensitive, rapid, accurate and multiplexed determination of Ag+, and also opened a new pathway for the detection of other heavy metals based on HEA-CM dual-mode strategy.

Integrating Artificial DNAzymes with Natural Enzymes on 2D MOF Hybrid Nanozymes for Enhanced Treatment of Bacteria-Infected Wounds.

Removal of invasive bacteria is critical for proper wound healing. This task is challenging because these bacteria can trigger intense oxidative stress and gradually develop antibiotic resistance. Here, the use of a multienzyme-integrated nanocatalytic platform is reported for efficient bacterial clearance and mitigation of inflammatory responses, constructed by physically adsorbing natural superoxide dismutase (SOD), in situ reduction of gold nanoparticles (Au NPs), and incorporation of a DNAzyme on 2D NiCoCu metal-organic frameworks (DNAzyme/SOD/Au@NiCoCu MOFs, termed DSAM), which can adapt to infected wounds. O2 and H2O2 replenishment is achieved and alleviated the hypoxic microenvironment using the antioxidant properties of SOD. The H2O2 produced during the reaction is decomposed by peroxidase (POD)-like activity enhanced by Au NPs and DNAzyme, releasing highly toxic hydroxyl radicals (•OH) to kill the bacteria. In addition, it possesses glutathione peroxidase (GPx)-like activity, which depletes GSH and prevents •OH loss. Systematic antimicrobial tests are performed against bacteria using this multienzyme-integrated nanoplatform. A dual-mode strategy involving natural enzyme-enhanced antioxidant capacity and artificial enzyme-enhanced •OH release to develop an efficient and novel enzyme-integrated therapeutic platform is integrated.

A dual-mode aptasensor based on freeze–thaw induced aggregation of gold nanoparticles and FRET for Staphylococcus aureus detection

The foodborne pathogen Staphylococcus aureus (S. aureus), known for its high virulence, presents a substantial risk to food safety. In this study, we proposed a detection platform utilizing the aptamer-induced aggregation of gold nanoparticles (AuNPs) through freeze–thaw and the fluorescence resonance energy transfer (FRET) between FITC and AuNPs. This platform offered an efficient means of identifying S. aureus. The thiolated aptamer exhibited specific binding affinity towards S. aureus, whereas AuNPs with the unbound aptamer underwent varying degrees of aggregation following freeze–thaw, leading to distinct alterations in color. After the aggregation of AuNPs, FRET between AuNPs and FITC diminished, followed by a gradual restoration of fluorescence. Under optimal experimental conditions, the colorimetric mode exhibited a detection limit of 5 CFU/mL for S. aureus, while the fluorescence mode demonstrated a detection limit of 2 CFU/mL. The validity of the developed method was confirmed through the plate counting method, with no significant disparities observed in the obtained results. Compared to the plate culture method, the proposed dual-mode strategy can be completed within 95 min, greatly shortening the detection time. Consequently, this method holds promising potential for the rapid and sensitive analysis of S. aureus.