Enhanced Photothermal Activity of Nanoconjugated System via Covalent Organic Frameworks as the Springboard.

The development of nanomaterials with high photothermal conversion efficiency has been a hot issue. In this work, a novel photothermal nanomaterial is synthesized using Prussian blue nanocubes (PBNCs) as the photothermal active substance and covalent organic framework (COF) as the substrate. The as-prepared COF@PBNCs show a high photothermal conversion efficiency of 59.1%, significantly higher than that of pure PBNCs (32.5%). A new circuit path is generated with the combination of COF, which prevents the direct combination of thermal electrons and holes, as well as enhances the nonradiation transition of PBNCs. Besides, the imine groups on COF as the coordination and reduction agent allow the in situ growth of PBNCs, and the dense micropores of COF as the ideal heat conduction channels can also be the potential factors for the enhanced photothermal property. The photothermal property of COF@PBNCs is further used in the construction of immunosensor for the detection of furosemide (FUR). With the help of handheld thermal imager, the concentration of FUR can be easily read, thus shedding a new light in the construction of visual sensor for simple and low-cost point-of-care testing.

Distance-Based Self-Powered Signal Transduction of Ion-Selective Electrodes to an Electronic Paper Display Array.

In this article, we report on the first distance-based readout self-powered potentiometric sensor. The approach is considered more user-friendly for detection by the naked eye and is less prone to optical interferences compared with a direct observation of the pixel darkening. pH-selective electrodes were chosen as a model system to demonstrate the principle in which seven bar-shaped pixels connected in series on one e-paper share one common ground. By connecting each of the pixels serially to capacitors of different capacitances, the fraction of the measurement cell voltage loaded onto the pixels becomes controllable. Consequently, the pixels give different gray values when powered by the same ion-selective electrode (ISE). As a result, the pH information on the sample is visualized as a distance-based signal and the dependence between the capacitance and 1/K (the reciprocal slope in the relationship between absorbance and pH) was constructed. In the current system, a 1 µF capacitance difference changes the value of 1/K by 4.18. With the current setup, the pH accuracy is about 0.5 when comparing the e-paper output to a color card.

Self-Powered Potentiometric Sensor Based on a Passive Signal Amplifier with Electronic Paper Display.

Self-powered potentiometric sensors are attractive because of their simple operation, low cost, fast response, and ability to be integrated with electronic components. Self-powered potentiometric sensors that give a direct colorimetric output are especially interesting, because no power supply is needed, which dramatically reduces waste. Recently reported work from our group using an electronic paper display, however, exhibits limitations, because the visualization of small pH changes is difficult. A self-powered ion-selective potentiometric sensor is introduced here that may amplify the e-paper pixel sensitivity by improving the self-powered circuit. The voltage is amplified by changing the circuit from incorporating parallel to incorporating serial capacitors. With three such capacitors, a greatly improved sensitivity is observed, amplifying the absorbance 3-fold. A portable device is realized that changes the position of the capacitors from parallel to serial through a simple mechanical sliding action. As a result, the pH information on the sample is more easily visualized with a pH uncertainty of about 0.1 when comparing the e-paper output to a color card.

Efficient Nanozyme-Triggered Pressure Sensor for Point-of-Care Immunoassay: Visual Sensing and Time Readout Device.

Point-of-care testing (POCT), with its portability and high sensitivity, is an analytical device for rapid on-site sensing and detection. In this study, a POCT device was designed for the portable detection of illegal additives by integrating a coil device that can visually sense color distance and a two-electrode electrochemical system. Real-time monitoring of pressure changes was achieved by driving CeO2@Pt/Au nanoparticle (NP)-labeled antibodies into a competitive immunoreaction, in which CeO2 and Pt/Au synergistically catalyzed the production of large amounts of O2 from H2O2, leading to a significant increase in gas within the closed chamber. Attractively, the coil device converted the pressure stimulus into visually readable change in distance for semi-quantitative detection of the target substance, while the electrical signal output caused by the changes of the solution around the electrodes achieved accurate and reliable quantification of the target. In addition, the proposed dual-mode pressure immunoassay device has acceptable selectivity, stability, and reproducibility. Herein, this portable device, which enables target concentration readings by converting pressure into multiple signals, provides an effective way to visualize POCT assays in resource-limited areas.

Engineered DNAzyme Enables Homogeneous Detection of Cereulide via Polychromic Fluorescence Modality.

Cereulide, the exotoxin of emetic Bacillus cereus, has garnered considerable attention due to its capacity to produce foodborne poisonings and great chemical stability. Herein, a G-quadruplex-hemin DNAzyme-based biosensor was developed to detect cereulide in the homogeneous solution. Due to the special ring structure and high affinity to K+, cereulide can be attracted and intercalated into the G-quadruplex; thus, the properties of the G4 DNAzyme can be altered. The melting temperature (Tm) of the G4 DNAzyme in the presence or absence of cereulide was 58.75 and 50.10 °C, respectively, proving the intercalation of cereulide into the G4 DNAzyme. By using the polychromic fluorescence modality of CdTe quantum dots and o-phenylenediamine to assess the variation in the catalytic activity of the DNAzyme, the intercalation of cereulide had bidirectional effects in G4 DNAzyme-mediated reactions, showing that the fluorescence intensity of CdTe quantum dots displayed a linear relationship with the concentration of cereulide from 0.16 to 40 µg/mL with the limit of detection (LOD) of 0.10 µg/mL, while the fluorescence intensity of DAP exhibited a linear relationship with the concentration of cereulide from 0.02 to 40 µg/mL with the LOD of 0.01 µg/mL. It will be a perspective step of controlling cereulide as a hazardous material in food or the environment.

Well-Aligned Track-Accelerated Tripedal DNA Walker for Photoelectrochemical Recognition of Dual-miRNAs Based on Molecular Logic Gates.

Post-transcriptional regulators, microRNAs (miRNAs), are involved in the occurrence and progression of various diseases. However, due to the complexity of disease-related miRNA regulatory networks, the typing and identification of miRNAs have remained challenging. Herein, a linear ladder-like DNA nanoarchitecture (LDN) was constructed to promote the movement efficiency of the tripedal DNA walker (T-walker), which was combined with the DNA-based logic gates and the PTCDA@PDA/CdS/WO3 photoelectrode to develop a novel biosensor for the detection of dual-miRNAs. Two miRNAs, miR-122 and miR-21, were used as targets to operate the logic module, while its output, trigger strands (TSs), initiated a catalytic hairpin assembly (CHA) reaction to form a T-walker. By using LDN as the track, the T-walker efficiently unfolded hairpin 4, which further hybridized with the alkaline phosphatase-modified hairpin 5 (AP-H5). The remaining AP can catalyze the ascorbic acid 2-phosphate (AAP) into ascorbic acid (AA), an ideal electron donor, thus resulting in a photocurrent change. The photocurrent signals of both AND and OR gates displayed a linear relationship with the logarithm of dual-miRNA concentrations with detection limits of 10.1 and 13.6 fM, respectively. Moreover, the intelligent and rational design of DNA tracks gives impetus to create a well-organized sensing interface with wide application in clinical diagnosis and cancer monitoring.

DNA Nanomachine-Driven Heterogeneous Quadratic Amplification for Sensitive and Programmable miRNA Profiling.

Inspired by the molecular crowding effect in biological systems, a novel heterogeneous quadratic amplification molecular circuit (HEQAC) was developed for sensitive bimodal miRNA profiling (HEQAC-BMP) by combining an MNAzyme-based DNA nanomachine with an entropy-driven catalytic hairpin assembly (E-CHA) autocatalytic circuit. Utilizing ferromagnetic nanomaterials as the substrate for DNA nanomachines, a biomimetic heterogeneous interface was established; thus, a localized molecular crowding system was created that can elevate the local reaction concentration and accelerate the molecular recognition process for a significant threshold signal. Simultaneously, the threshold signal undergoes further amplification by E-CHA and is transformed into a chemical signal, enabling a colorimetric-fluorescence bimodal signal readout. The HEQAC-BMP enables miRNA detection from 10 aM to 10 nM with detection limits of 3.7 aM (colorimetry) and 4.8 aM (fluorometry), respectively. Moreover, the design principle and strategy of HEQAC-BMP can be customized to address other critical viruses or diseases with life-threatening and socioeconomic impacts, enhancing healthcare outcomes for individuals.

Advances in immunoassay-based strategies for mycotoxin detection in food: From single-mode immunosensors to dual-mode immunosensors.

Mycotoxin contamination in foods and other goods has become a broad issue owing to serious toxicity, tremendous threat to public safety, and terrible loss of resources. Herein, it is necessary to develop simple, sensitive, inexpensive, and rapid platforms for the detection of mycotoxins. Currently, the limitation of instrumental and chemical methods cannot be massively applied in practice. Immunoassays are considered one of the best candidates for toxin detection due to their simplicity, rapidness, and cost-effectiveness. Especially, the field of dual-mode immunosensors and corresponding assays is rapidly developing as an advanced and intersected technology. So, this review summarized the types and detection principles of single-mode immunosensors including optical and electrical immunosensors in recent years, then focused on developing dual-mode immunosensors including integrated immunosensors and combined immunosensors to detect mycotoxins, as well as the combination of dual-mode immunosensors with a portable device for point-of-care test. The remaining challenges were discussed with the aim of stimulating future development of dual-mode immunosensors to accelerate the transformation of scientific laboratory technologies into easy-to-operate and rapid detection platforms.

Handheld Platform for Sensitive Rosiglitazone Detection: Immunosensor Based on a Time-Based Readout Device.

The detection of rosiglitazone (RSG) in food is of great importance since the excessive intake of RSG could cause adverse effects on the human body. Although liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry are the preliminary methods for the detection of hazardous materials in food, they are not suitable for point-of-care or on-site detection. Herein, a time-based readout (TBR) device with an application software (APP) controlled by a smart phone was developed for the sensitive and selective immunoassay of RSG. The homemade TBR device was based on a two-electrode system, where the immune molecule-modified glassy carbon electrode was used as the bioanode, and Prussian blue-modified FTO was used as the cathode. By using Au-modified octahedral Cu2O with high catalytic activity as mimetic peroxidase, an insulating layer was generated on the cathode by catalyzing 4-chloro-1-naphthol (4-CN) into benzo-4-chlorohexadienone (B4Q). The time to reach a fixed potential varied indirectly with the concentrations of RSG and was recognized by the APP, while the electrochromic property on the cathode was also correspondingly changed. Under optimum conditions, both the square root of the time and the chroma value of the electrochromism exhibited linear responses for the detection of RSG ranging from 5 × 10-10 to 5 × 10-7 g/L, while the limits of detection were 8.2 × 10-11 and 1.3 × 10-10 g/L, respectively. With easy operation and portability, this TBR device showed a promising application for point-of-care monitoring of hazardous materials in food or the environment.

Development of Cu-doped CeO2 nanospheres mimic nanozyme-based immunoassay for the specific screening of Bacillus cereus.

Due to the highly similar genetic background, it is difficult to distinguish Bacillus cereus (B. cereus) with other members of B. cereus group. Herein, an antibody-based colorimetric immunoassay using Cu-doped CeO2 nanospheres as peroxidase mimics was developed for the detection of B. cereus in food. First, monoclonal antibodies (mAbs) and polyclonal antibody (pAb) with good specificity to B. cereus were prepared and characterized. Second, the regular-shaped hollow Cu/CeO2 nanospheres with highly catalytic activity and biocompatibility were synthesized as mimic nanozymes to capture secondary antibody. Finally, a sandwich colorimetric immunoassay for the specific and sensitive detection of B. cereus was developed, showing linear detection range from 3.2 × 102 to 1 × 105 CFU/mL and a limit detection of 1.7 × 102 CFU/mL. The developed immunoassay holds great potential as an effective tool for detecting B. cereus in food poisoning.

Multiplex optical bioassays for food safety analysis: Toward on-site detection.

Food safety analysis plays a significant role in controlling food contamination and supervision. In recent years, multiplex optical bioassays (MOBAs) have been widely applied to analyze multiple hazards due to their efficiency and low cost. However, due to the challenges such as multiplexing capacity, poor sensitivity, and bulky instrumentation, the further application of traditional MOBAs in food screening has been limited. In this review, effective strategies regarding food safety MOBAs are summarized, such as spatial-resolution modes performed in multi-T lines/dots strips or arrays of strip/microplate/microfluidic chip/SPR chip and signal-resolution modes employing distinguishable colorimetric/luminescence/fluorescence/surface plasma resonance/surface-enhanced Raman spectrum as signal tags. Following this, new trends on how to design engineered sensor architecture and exploit distinguishable signal reporters, how to improve both multiplexing capacity and sensitivity, and how to integrate these formats into smartphones so as to be mobile are summarized systematically. Typically, in the case of enhancing multiplexing capacity and detection throughput, microfluidic array chips with multichannel architecture would be a favorable approach to overcome the spatial and physical limitations of immunochromatographic assay (ICA) test strips. Moreover, noble metal nanoparticles and single-excitation, multiple-emission luminescence nanomaterials hold great potential in developing ultrasensitive MOBAs. Finally, the exploitation of innovative multiplexing strategy hybridized with powerful and widely available smartphones opens new perspectives to MOBAs. In future, the MOBAs should be more sensitive, have higher multiplexing capacity, and easier instrumentation.

"Dual-Signal-On" Integrated-Type Biosensor for Portable Detection of miRNA: Cas12a-Induced Photoelectrochemistry and Fluorescence Strategy.

The abnormal expression of microRNA (miRNA) can affect the RNA transcription and protein translation, leading to tumor progression and metastasis. Currently, the accurate detection of aberrant expression of miRNA, particularly using a portable detection system, remains a great challenge. Herein, a novel dual-mode biosensor with high sensitivity and robustness for miR-21 detection was developed based on the cis-cleavage and trans-cleavage activities of Cas12a. miRNA can be combined with hairpin DNA-horseradish peroxidase anchored on a CdS/g-C3N4/B-TiO2 photoelectrode, thus the nonenzymatic amplification was triggered to form numerous HRP-modified double-stranded DNA (HRP-dsDNA). Then, HRP-dsDNA can be specifically recognized and efficiently cis-cleaved by Cas12a nucleases to detach HRP from the substrate, while the remaining HRP on HRP-dsDNA can catalyze 4-chloro-1-naphthol (4-CN) to form biocatalytic precipitation (BCP) on the surface of the photoelectrode, and thus the photocurrent can be changed. Meanwhile, the trans-cleavage ability of Cas12a was activated, and nonspecifically degrade the FQ-reporter and a significant fluorescence signal can be generated. Such two different kinds of signals with independent transmission paths can mutually support to improve the performance of the detection platform. Besides, a portable device was constructed for the point-of-care (POC) detection of miR-21. Moreover, the dual-mode detection platform can be easily expanded for the specific detection of other types of biomarkers by changing the sequence of hairpin DNA, thereby promoting the establishment of POC detection for early cancer diagnosis.

Capsulation of AuNCs with AIE Effect into Metal-Organic Framework for the Marriage of a Fluorescence and Colorimetric Biosensor to Detect Organophosphorus Pesticides.

Organophosphorus pesticides (OPs) can inhibit the activity of acetylcholinesterase (AChE) to induce neurological diseases. It is significant to exploit a rapid and sensitive strategy to monitor OPs. Here, a metal-organic framework (MOF) acted as a carrier to encapsulate AuNCs, which can limit the molecular motion of AuNCs, trigger the aggregation-induced emission (AIE) effect, and exhibit a strong fluorescence with a fluorescence lifetime and quantum yield of 6.83 µs and 4.63%, respectively. Then, the marriage of fluorescence and colorimetric signals was realized on the basis of the dual function of the enzymolysis product from AChE and choline oxidase (CHO) on AuNCs@ZIF-8. First, it can decompose ZIF-8 to weaken the restraint on AuNCs, and thus the fluorescence receded. Second, it can be used as a substrate for the peroxidase mimics of the released AuNCs to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) and a visible blue appeared. Thus, on the basis of the inhibition of AChE activity by OPs, a fluorescence-colorimetric dual-signal biosensor was established. In addition, colorimetric paper strips were exploited to realize a visual semiquantitative detection, and a smartphone APP was developed to make the visualization results more precise and realize real-time supervision of pesticide contamination.

A needle-like cobalt-based bifunctional catalyst supported on carbon materials for effective overall water splitting.

Nowadays, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) dual-functional electrocatalyst in the field of water electrolysis has great advantages in reducing costs and simplifying electrolytic cell installations. Herein, Co-Mo particles were electrodeposited on the carbon nanotubes (CNTs)/reduced graphene oxide (rGO)-modified copper foam to form the Co-Mo-CNTs/rGO-copper foam (CF), then it was subjected to a certain potential for alkaline etching, thus needle-like E-Co-Mo-CNTs/rGO-CF was synthesized. Results showed that the material surface mainly formed by the interlacing of Co oxide was more conducive to capturing the intermediates in the HER/OER reaction, while the CNTs/rGO-CF structure was closely connected to the metal layer, making excellent performance of total hydrolysis in KOH. The electrocatalyst exhibited remarkable electrocatalytic activity for HER and OER in 1 M KOH, requiring only 71 and 268 mV overpotential to drive 10 mA·cm-2, respectively. Especially, only a battery voltage of 1.52 V was needed to drive 10 mA·cm-2in two-electrode system for overall water splitting. This work provides a method for the construction of dual-functional electrocatalyst that combined carbon materials and metals.

A multi-colorimetric immunosensor for visual detection of ochratoxin A by mimetic enzyme etching of gold nanobipyramids.

A multi-colorimetric immunosensor basing on the mimetic enzyme etching of gold nanobipyramids (Au NBPs) was established to detect ochratoxin A (OTA). Octahedral Cu2O nanoparticles were successfully synthesized through a selective surface stabilization strategy, which can exhibit a peroxidase-like ability to oxidize 3,3',5,5'-tetramethylbenzidine (TMB). Au NBPs can be etched by the product, TMB2+, to form a significant longitudinal peak blue shift of local surface plasmon resonance. During the construction of the immunosensor, the microplate was coated with dopamine to immobilized OTA antigens, followed by the immunoreaction of OTA antibody and the Cu2O-labled secondary antibody. A linear relationship can be found between the local surface plasmon resonance (LSPR) peak changes with the logarithm of OTA concentration in a wide range from 1 ng/L to 5 µg/L, while the detection limit was 0.47 ng/L. Meanwhile, the approximate OTA concentration can be conveniently and intuitively observed by the vivid color changes. Benefiting from the high specificity, the proposed multi-colorimetric immunoassay detection of OTA in millet samples was achieved, indicating the available potential of the immunoassay for the determination of OTA in real samples.

CQMUH-011 mitigates autoimmune hepatitis via inhibiting the function of T lymphocytes.

CQMUH-011 is a modified adamantane sulfonamide compound, that inhibits macrophage proliferation and possesses anti-inflammatory properties. Here, fresh mouse splenocytes were obtained and stimulated with concanavalin A (ConA, 5 µg/ml) in vitro; and experimental autoimmune hepatitis (AIH) was induced by ConA (20 mg/kg, iv) in vivo, to clarify the protective effects of CQMUH-011 against AIH and its possible mechanisms. Our results demonstrated that CQMUH-011 pretreatment can dose-dependently inhibit the proliferation of splenocytes in vitro. In vivo, CQMUH-011 administration reduced the hepatic histopathological score and the infiltration of lymphocytes in the liver parenchyma; additionally, it downregulated the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and pro-inflammatory cytokines interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in serum, as well as those of methane dicarboxylic aldehyde and myeloperoxidase in the liver tissues. It also down-regulated the expression of p-NF-κB and related proteins in the liver tissues. Furthermore, CQMUH-011 could maintain the balance of CD3+ CD4+ /CD3+ CD8+ and decrease the percentages of CD8+ CD69+ and CD4+ CD25+/- CD69+ T-cells in the splenocytes of ConA-challenged mice. Moreover, we found thatCD4+ CD25+/- CD69+ T-cells were significantly correlated with ALT levels, especially CD4+ CD25- CD69+ T-cells. In conclusion, CQMUH-011 exerts potential protective effects against ConA-induced hepatitis, which may be partially attributed to its inhibition of T cells, especially the suppression of the proliferation of CD4+ CD25- CD69+ and CD8+ CD69+ subsets in the spleen. CQMUH-011 also reduced the early apoptosis of lymphocytes in the thymus.

Open Surface Droplet Microfluidic Magnetosensor for Microcystin-LR Monitoring in Reservoir.

Establishing rapid, simple, and in situ detection of microcystin-LR (MC-LR) in drinking water sources is of significant importance for human health. To ease the situation that current methods cannot address, an open surface droplet microfluidic magnetosensor was designed and validated to quantify MC-LR in reservoir water, which is capable of (1) MC-LR isolation via MC-LR antibody-conjugated magnetic beads, (2) parallel and multistep analytical procedures in 15-array power-free and reusable active droplet microfluidic chips, (3) immunoassay incubation and fluorescence excitation within a miniaturized multifunctional 3D-printing optosensing accessory, and (4) signal read-out and data analysis by a user-friendly Android app. The proposed smartphone-based fluorimetric magnetosensor exhibited a low limit of detection of 1.2 × 10-5 µg/L in the range of 10-4 µg/L to 100 µg/L. This integrated and high throughput platform was utilized to draw an MC-LR contamination map for six reservoirs distributed in the Pearl River delta, Guangdong Province. It promises to be a simple and successful quantification method for MC-LR field detection, bringing many benefits to rapid on-site screening.

Facile synthesis of Mn-doped MoS2 nanosheets on carbon nanotubes as efficient electrocatalyst for hydrogen evolution reaction.

As a substitute of Pt-based catalysts, MoS2-based catalysts have been widely used in hydrogen evolution reaction, but the inherent low conductivity, limited active edges, self-stacking and agglomeration still hinder their activities. In this work, Mn-doped MoS2 nanosheets were vertically anchored on carbon nanotubes (CNTs) by the one-step hydrothermal reaction, in which Mn-O-C/Mo-O-C was considered as a bridge between Mn-MoS2 and CNTs. The doping of the Mn element enables the spreading of MoS2 on CNTs and the rapid escape of hydrogen bubbles from the electrode, while conductive CNTs with hydrophilicity can accelerate the electron transport process between the electrolyte and the material. With an overpotential of 150 mV at a current density of -10 mA cm-2 and a Tafel slope of 39 mV dec-1, this material exhibited excellent catalytic hydrogen evolution activity, which could open the path for designing commercial electrocatalysts.

Temporal Change in Paravalvular Leakage after Transcatheter Aortic Valve Replacement with a Self-Expanding Valve: Impact of Aortic Valve Calcification.

BACKGROUND: In patients undergoing transcatheter aortic valve replacement (TAVR), the severity of paravalvular leakage (PVL) may change during follow-up, however its mechanism is poorly understood. We aimed to explore temporal changes in PVL and possible predictors following TAVR. METHODS: A retrospective analysis was performed of all patients who had received a self-expanding valve. Multi-detector computed tomography was performed as pre-TAVR evaluation, including assessment of aortic valve calcification (AVC). The patients received transthoracic echocardiography at baseline and 30 days, 6 months, and 1 year after TAVR. RESULTS: In total, 93 patients who had received a self-expanding valve during TAVR were identified. Various degrees of PVL were seen in 63 patients, with moderate/severe PVL in 21 (22.6%). In multivariate analysis, the predictors of moderate/severe PVL were: chronic pulmonary disease, high degree of AVC, and an increased annulus perimeter. After 1 year of follow-up, PVL deteriorated from mild to moderate in 2 patients, while an improvement of ≥ 1 grade was seen in 25 patients. Of 21 patients with post-TAVR moderate/severe PVL, 9 had an improvement of ≥ 1 grade and 12 did not. The degree of AVC was significantly lower in those with PVL improvement (Agatston score 3068 ± 1816 vs. 6418 ± 3222; p = 0.01). AVC was a good predictor for an improvement in PVL, and the area under the receiver operating characteristic curve was 0.82 (95% confidence interval = 0.63-1.00, p = 0.01), with a cut-off value of 5210. CONCLUSIONS: In this study, 43% (9/21) of the patients with moderate/severe PVL after self-expanding TAVR had an improvement of ≥ 1 grade within 1 year, and a low degree of AVC was predictive of this improvement.

Colorimetric detection of nucleic acid sequences in plant pathogens based on CRISPR/Cas9 triggered signal amplification.

A colorimetric method is presented for the detection of specific nucleotide sequences in plant pathogens. It is based on the use of CRISPR/Cas9-triggered isothermal amplification and gold nanoparticles (AuNPs) as optical probes. The target DNA was recognized and broken up by a given Cas9/sgRNA complex. After isothermal amplification, the product was hybridized with oligonucleotide-functionalized AuNPs. This resulted in the aggregation of AuNPs and a color change from wine red to purple. The visual detection limit is 2 pM of DNA, while a linear relationship exists between the ratio of absorbance at 650 and 525 nm and the DNA concentration in the range from 0.2 pM to 20 nM. In contrast to the previous CRISPR-based amplification platforms, the method has significantly higher specificity with the single-base mismatch and can be visually read out. It was successfully applied to identify the Phytophthora infestans genomic DNA. Graphical abstract Schematic presentation of a colorimetric method for detection of Phytophthora infestans genomic DNA based on CRISPR/Cas9-triggered isothermal amplification. The Cas9 endonuclease cleaves DNA at the design site and the color changes from red to purple with increasing target DNA concentration.