Background Signal Suppression Research Articles

Fast, automated, real-time 3D passive balloon catheter tracking during MRI-guided cardiac catheterization using orthogonal projection imaging and real-time image-based catheter detection.

MRI-guidance of cardiac catheterization is currently performed using one or multiple 2D imaging planes, which may be suboptimal for catheter navigation, especially in patients with complex anatomies. The purpose of the work was to develop a robust real-time 3D catheter tracking method and 3D visualization strategy for improved MRI-guidance of cardiac catheterization procedures. A fast 3D tracking technique was developed using continuous acquisition of two orthogonal 2D-projection images. Each projection corresponds to a gradient echo stack of slices with only the central k-space lines being collected for each slice. To enhance catheter contrast, a saturation pulse is added ahead of the projection pair. An offline image processing algorithm was developed to identify the 2D coordinates of the balloon in each projection image and to estimate its corresponding 3D coordinates. Post-processing includes background signal suppression using an atlas of background 2D-projection images. 3D visualization of the catheter and anatomy is proposed using three live sagittal, coronal, and axial (MPR) views and 3D rendering. The technique was tested in a subset of a catheterization step in three patients undergoing MRI-guided cardiac catheterization using a passive balloon catheter. The extraction of the catheter balloon 3D coordinates was successful in all patients and for the majority of time-points (accuracy >96%). This tracking method enabled a novel 3D visualization strategy for passive balloon catheter, providing enhanced anatomical context during catheter navigation. The proposed tracking strategy shows promise for robust tracking of passive balloon catheter and may enable enhanced visualization during MRI-guided cardiac catheterization.

Image quality of whole-body diffusion MR images comparing deep-learning accelerated and conventional sequences.

To compare the image quality of deep learning accelerated whole-body (WB) with conventional diffusion sequences. Fifty consecutive patients with bone marrow cancer underwent WB-MRI. Two experts compared axial b900 s/mm2 and the corresponding maximum intensity projections (MIP) of deep resolve boost (DRB) accelerated diffusion-weighted imaging (DWI) sequences (time of acquisition: 6:42 min) against conventional sequences (time of acquisition: 14 min). Readers assessed paired images for noise, artefacts, signal fat suppression, and lesion conspicuity using Likert scales, also expressing their overall subjective preference. Signal-to-noise and contrast-to-noise ratios (SNR and CNR) and the apparent diffusion coefficient (ADC) values of normal tissues and cancer lesions were statistically compared. Overall, radiologists preferred either axial DRB b900 and/or corresponding MIP images in almost 80% of the patients, particularly in patients with a high body-mass index (BMI > 25 kg/m2). In qualitative assessments, axial DRB images were preferred (preferred/strongly preferred) in 56-100% of cases, whereas DRB MIP images were favoured in 52-96% of cases. DRB-SNR/CNR was higher in all normal tissues (p < 0.05). For cancer lesions, the DRB-SNR was higher (p < 0.001), but the CNR was not different. DRB-ADC values were significantly higher for the brain and psoas muscles, but not for cancer lesions (mean difference: + 53 µm2/s). Inter-class correlation coefficient analysis showed good to excellent agreement (95% CI 0.75-0.93). DRB sequences produce higher-quality axial DWI, resulting in improved MIPs and significantly reduced acquisition times. However, differences in the ADC values of normal tissues need to be considered. Deep learning accelerated diffusion sequences produce high-quality axial images and MIP at reduced acquisition times. This advancement could enable the increased adoption of Whole Body-MRI for the evaluation of patients with bone marrow cancer. Deep learning reconstruction enables a more than 50% reduction in acquisition time for WB diffusion sequences. DRB images were preferred by radiologistsin almost 80% of cases due to fewer artefacts, improved background signal suppression, higher signal-to-noise ratio, and increased lesion conspicuity in patients with higher body mass index. Cancer lesion diffusivity from DRB images was not different from conventional sequences.

Adding Value of Diffusion Weighted Imaging with Background Signal Suppression {DWIBS} in Loco-Regional Staging of Gynecological Cancers

Adding Value of Diffusion Weighted Imaging with Background Signal Suppression {DWIBS} in Loco-Regional Staging of Gynecological Cancers

Background signal suppression by opposite polarity subtraction for targeted DNP NMR spectroscopy on mixture samples.

A novel method for background signal suppression is introduced to improve the selectivity of dynamic nuclear polarization (DNP) NMR spectroscopy in the study of target molecules within complex mixtures. The method uses subtraction between positively and negatively enhanced DNP spectra, leading to an improved contrast factor, which is the ratio between the target and background signal intensities. The proposed approach was experimentally validated using a reverse-micelle system that confines the target molecules together with the polarizing agent, OX063 trityl. A substantial increase in the contrast factor was observed, and the contrast factor was optimized through careful selection of the DNP build-up time. A simulation study based on the experimental results provides insights into a strategy for choosing the appropriate DNP build-up time and the corresponding selectivity of the method. Further analysis revealed a broad applicability of the technique, encompassing studies from large biomolecules to surface-modified polymers, depending on the nuclear spin diffusion rate with a range of gyromagnetic ratios.

Radiomics model of diffusion-weighted whole-body imaging with background signal suppression (DWIBS) for predicting axillary lymph node status in breast cancer.

In breast cancer diagnosis and treatment, non-invasive prediction of axillary lymph node (ALN) metastasis can help avoid complications related to sentinel lymph node biopsy. This study aims to develop and evaluate machine learning models using radiomics features extracted from diffusion-weighted whole-body imaging with background signal suppression (DWIBS) examination for predicting the ALN status. A total of 100 patients with histologically proven, invasive, clinically N0 breast cancer who underwent DWIBS examination consisting of short tau inversion recovery (STIR) and DWIBS sequences before surgery were enrolled. Radiomic features were calculated using segmented primary lesions in DWIBS and STIR sequences and were divided into training (n = 75) and test (n = 25) datasets based on the examination date. Using the training dataset, optimal feature selection was performed using the least absolute shrinkage and selection operator algorithm, and the logistic regression model and support vector machine (SVM) classifier model were constructed with DWIBS, STIR, or a combination of DWIBS and STIR sequences to predict ALN status. Receiver operating characteristic curves were used to assess the prediction performance of radiomics models. For the test dataset, the logistic regression model using DWIBS, STIR, and a combination of both sequences yielded an area under the curve (AUC) of 0.765 (95% confidence interval: 0.548-0.982), 0.801 (0.597-1.000), and 0.779 (0.567-0.992), respectively, whereas the SVM classifier model using DWIBS, STIR, and a combination of both sequences yielded an AUC of 0.765 (0.548-0.982), 0.757 (0.538-0.977), and 0.779 (0.567-0.992), respectively. Use of machine learning models incorporating with the quantitative radiomic features derived from the DWIBS and STIR sequences can potentially predict ALN status.

The Role of Whole- Body Diffusion Imaging with Background Signal Suppression (DWBS) in comparison with PET/CT in assessment of lymphoma patients

Abstract Background Malignant lymphomas [Hodgkin lymphomas (HL) and non-Hodgkin lymphoma (NHL)] rank third in incidence, of all childhood cancers, Moreover, in adolescents (aged 15-19 years) the malignant lymphomas are the leading cause of cancer. Furthermore, as with many other cancers, the likelihood of an individual being diagnosed with lymphoma increases markedly with age, with the median age at diagnosis being 67 years. Aim of the Work To compare between F-18-FDG PET-CT and whole-body diffusion-weighted imaging MR protocol (DWIBS) for initial staging and post chemotherapy evaluation in patients with pathologically proven lymphoma (Hodgkin and Non-Hodgkin). Patients and Methods The study is conducted on 32 patients with pathologically proven lymphoma to perform 18-F-FDG PET/CT either for pre-treatment initial staging or for evaluation of response to chemotherapy. A total of 22 had HD (69%) and 10 had NHL (31%). Staging PET/CT and WB-MRI/DWIBS were done at time of diagnosis in 19 of the 32 patients (59.4%), where immediate post-therapy PET/CT and WB-MRI-DWIBS were performed 13 patients (40.6%). Accuracy measures were calculated for PET CT and DWIBS. Results Accuracy measures confirm the higher sensitivity and specificity of PET-CT over DWIBS. Results for F-18 FDG PET/CT were clearly superior with statistically higher sensitivity, specificity, accuracy, PPV &amp; NPV (96.3%, 99.16%, 98.43%, 97.5% and 98.75%) compared to (83.95%, 97.91%, 94.38%, 93.15% and 94.74%) for DWIBS results respectively. Conclusion F-18-FDG PET-CT remains a cornerstone in the evaluation of malignant lymphoma patients; it has significant higher sensitivity, specificity and overall accuracy compared to WB-MRI/DWIBS in HL and NHL patients, either in initial staging or in post therapy evaluation. WB-MRI/DWIBS in HL and NHL patients, either in initial staging or in post therapy evaluation. WB-MRI/DWIBS despite of its relatively longer acquisition time may provide a complementary tool for FDG PET CT.

Development of a background signal suppression probe for 8-oxoguanine DNA glycosylase detection

8-oxoguanine DNA glycosylase (OGG), which plays a crucial role in base excision repair (BER), is an important biomarker. The existing highly sensitive fluorescent methods always need complicated amplification design. The method with high sensitivity and simple design at the same time is urgently needed. Here, we developed a highly sensitive detection method for OGG detection with lambda exonuclease and the background signal suppression probe. Through probe structure design, the steric hindrance and competitive binding effects successfully suppressed the background signal. We achieved sensitive detection of OGG with a simple design, and the limit of detection was 5.0 × 10−4 U mL−1. Moreover, the method was highly selective and successfully applied to OGG detection in biological samples, which shows the potential clinical application value.

Photoelectrocatalytic detection of NADH on n-type silicon semiconductors facilitated by carbon nanotube fibers

NADH is a key biomolecule involved in many biocatalytic processes as cofactor and its quantification can be correlated to specific enzymatic activity. Many efforts have been taken to obtain clean electrochemical signals related to NADH presence and lower its redox overpotential to avoid interferences. Suppression of background and secondary signals can be achieved by including a switchable electroactive surface, for instance, by using semiconductors able to harvest light energy and drive the excited electrons only when irradiated. Here we present the combination of a n-type Si semiconductor with fibers made of carbon nanotubes as electroactive surface for NADH quantification at low potentials only upon irradiation. The resulting photoelectrode responded linearly to NADH concentrations from 50 µM to 1.6 mM with high sensitivity (54 µA cm−2 mM−1). This system may serve as a biosensing platform for detection and quantification of dehydrogenases’ activity.

Magnetic Resonance Neurography of the Brachial Plexus Using 3D SHINKEI: Comparative Evaluation with Conventional Magnetic Resonance Sequences for the Visualization of Anatomy and Detection of Nerve Injury at 1.5T.

Background and Purpose:This work aims at optimizing and studying the feasibility of imaging the brachial plexus at 1.5T using 3D nerve-SHeath signal increased with INKed rest-tissue RARE imaging (3D SHINKEI) neurography sequence by comparing with routine sequences.Materials and Methods:The study was performed on a 1.5T Achieva scanner. It was designed in two parts: (a) Optimization of SHINKEI sequence at 1.5T; and (b) Feasibility study of the optimized SHINKEI sequence for generating clinical quality magnetic resonance neurography images at 1.5T. Simulations and volunteer experiments were conducted to optimize the T2 preparation duration for optimum nerve-muscle contrast at 1.5T. Images from the sequence under study and other routine sequences from 24 patients clinically referred for brachial plexus imaging were scored by a panel of radiologists for diagnostic quality. Injury detection efficacy of these sequences were evaluated against the surgical information available from seven patients.Results:T2 preparation duration of 50 ms gives the best contrast to noise between nerve and muscle. The images of 3D SHINKEI and short-term inversion recovery turbo spin-echo sequences are of similar diagnostic quality but significantly better than diffusion weighted imaging with background signal suppression. In comparison with the surgical findings, 3D SHINKEI has the lowest specificity; however, it had the highest sensitivity and predictive efficacy compared to other routine sequences.Conclusion:3D SHINKEI sequence provides a good nerve–muscle contrast and has high predictive efficacy of nerve injury, indicating that it is a potential screening sequence candidate for brachial plexus scans at 1.5T also.

The Role Of Diffusion Weighted Imaging With Background Signal Suppression (Dwibs) In Diagnosis Of Breast Lesions: Comparison With Contrast Enhanced Digital Mammography (Cedm)

The Role Of Diffusion Weighted Imaging With Background Signal Suppression (Dwibs) In Diagnosis Of Breast Lesions: Comparison With Contrast Enhanced Digital Mammography (Cedm)

Whole-body magnetic resonance/diffusion-weighted sequence with background signal suppression (WB-MR/DWIBS) vs. 18F-FDG PET/CT in diagnosis of lymphoma

BackgroundThe purpose of this study was to compare the performance of whole-body magnetic resonance/diffusion-weighted imaging with background signal suppression (WB-MR/DWIBS) method, with that of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT), for lesion detection and initial staging of patients with lymphoma using the histopathologically diagnosis as a reference standard.ResultsThirty-two patients with newly pathologically proven lymphoma were enrolled in this prospective study from May 2018 to January 2020 (27 males, 5 females). All patients underwent PET/CT followed by WB-MR/DWIBS as an attempt to compare the performance of both methods for lesion detection and initial staging in patients with lymphoma.The overall sensitivity, specificity, PPV, NPV, and accuracy of 18F-FDG-PET/CT vs WB-MR/DWIBS in correlation with reference standard data in detection of lymphoma were calculated for PET/CT 96%, 100%, 100%, 80%, and 97% while those of WB-MR/DWIBS were 93%, 76%, 96%, 61%, and 91%, respectively.Conclusion18F-FDG PET/CT remains the standard reference of imaging in evaluation of lymphoma due to its higher sensitivity and specificity over WB-MR/DWIBS. Future studies with larger cohorts are necessary for better evaluation of the role of WB-MR/DWIBS in lymphoma patients. The current study highlights the potential complementary role of WB-MRI/DWIBS in the context of bone marrow involvement evaluation omitting unnecessary bone marrow biopsy.

Subtractive NCE-MRA: Improved background suppression using robust regression-based weighted subtraction.

To correct the intensity difference of static background signal between bright blood images and dark blood images in subtractive non-contrast-enhanced MR angiography using robust regression, thereby improving static background signal suppression on subtracted angiograms. Robust regression (RR), usingiteratively reweighted least squares,is used to calculate the regression coefficient of background tissues from a scatter plot showing the voxel intensity of bright blood images versus dark blood images. The weighting function is based on either the Euclidean distance from the estimated regression line or the deviation angle. Results from RR using the deviation angle (RRDA), conventional RR using the Euclidean distance, and ordinary leastsquares regression were compared with reference values determined manually by two observers. Performance was evaluated over studies using different sequences, including 36 thoracic flow-sensitive dephasing data sets, 13 iliac flow-sensitive dephasing data sets, and 26 femoral fresh blood imaging data sets. RR deviation angle achieved robust and accurate performance in all types of images, with small bias, small mean absolute error, and high-correlation coefficients with reference values. Background tissues, such as muscle, veins, and bladder, were suppressed while the vascular signal was preserved. Euclidean distance gave good performance for thoracic and iliac flow-sensitive dephasing, but could not suppress background tissues in femoral fresh blood imaging. Ordinary least squares regression was sensitive to outliers and overestimated regression coefficients in thoracic flow-sensitive dephasing. Weighted subtraction using RR was able to acquire the regression coefficients of background signal and improve background suppression of subtractive non-contrast-enhanced MR angiography techniques. RR deviation angle has the most robust and accurate overall performance among three regression methods.

Solvent suppression in solid-state DNP NMR using Electronic Mixing-Mediated Annihilation (EMMA).

We show here that the Electronic Mixing-Mediated Annihilation (EMMA) method, previously reported for the suppression of background signals in solid-state nuclear magnetic resonance spectra, can be successfully applied to remove the solvent signals observed in the case of nuclear magnetic resonance spectra obtained with dynamic nuclear polarization. The methodology presented here is applied to two standard sample preparation methods for dynamic nuclear polarization, namely, glass forming and incipient wetness impregnation. It is demonstrated that the Electronic Mixing-Mediated Annihilation method is complementary to the different methods for solvent suppression based on relaxation filters and that it can be used to preserve the quantitative information that might be present in the pristine spectra.

Ratio of spectral averaged cross sections measured in standard 252Cf(sf) and 235U(nth,f) neutron fields

The results of systematic evaluations of spectrum averaged cross section (SACS) measurements in the fission neutron fields of 252Cf and 235U are presented. The data form a complete database of high-threshold experimental SACS measured in the same installation under the same conditions and using the same high purity germanium gamma spectrometer. This is crucial to reduce the uncertainty of the ratio and the data scattering and therefore, to minimize discrepancies compared to cross section measured under different conditions in different laboratories. This new dataset complements and extends earlier experimental evaluations. The total emission of the 252Cf neutron source during the experiments varied from 9.5E8 to 4.5E8 neutrons per second. The emission was derived in accordance to the data in the Certificate of Calibration involving absolute flux measurements in a manganese sulphate bath. Concerning 235U fission neutron field, the irradiations were carried out in a specifically designed core assembled in the zero power light water LR-0 reactor. This special core has a well described neutron field. After the irradiation, the low volume irradiated samples to be measured by gamma spectrometry were placed directly on the upper cap of a coaxial high purity germanium (HPGe) detector in a vertical configuration (ORTEC GEM35P4). High volume samples were homogenized and strewn into the Marinelli beaker. The HPGe detector is surrounded by the lead shielding box with a thin inner copper cladding and covered with rubber for suppression of background signal and bremsstrahlung. The experimental reaction rates were derived for irradiated samples from the Net Peak Areas (NPA) measured using the semiconductor HPGe detector. The measured reaction rates are used to derive the spectrum-averaged cross sections. Furthermore, measured reaction rates are also compared with MCNP6 calculations using various nuclear data libraries, in particular IRDFF evaluations.

Multifunctional biocomposites based on collagen and keratin with properties for agriculture and industry applications

In this work, we optimize the performance of a previously proposed method for transferring parahydrogen induced polarization to “insensitive” spin-1/2 NMR (Nuclear Magnetic Resonance) nuclei, which have low gyromagnetic ratio and low natural abundance. By optimizing the reaction conditions and pressure of the parahydrogen gas and using adiabatically switched radiofrequency fields we achieve high polarization transfer efficiency and report carbon spin polarization of dimethyl acetylene dicarboxylate reaching 35%, which corresponds to 13C NMR signal enhancements of about 43,000 at 9.4 Tesla. Such polarization levels allow one to work with mM concentrations at natural carbon abundance and to detect 13C NMR signal in single scan. In combination with a pseudo phase cycle, the polarization transfer method used here also enables efficient suppression of unwanted background signals.

Polarization of low-γ nuclei by transferring spin order of parahydrogen at high magnetic fields.

In this work, we optimize the performance of a previously proposed method for transferring parahydrogen induced polarization to "insensitive" spin-1/2 NMR (Nuclear Magnetic Resonance) nuclei, which have low gyromagnetic ratio and low natural abundance. By optimizing the reaction conditions and pressure of the parahydrogen gas and using adiabatically switched radiofrequency fields we achieve high polarization transfer efficiency and report carbon spin polarization of dimethyl acetylene dicarboxylate reaching 35%, which corresponds to 13C NMR signal enhancements of about 43,000 at 9.4 Tesla. Such polarization levels allow one to work with mM concentrations at natural carbon abundance and to detect 13C NMR signal in single scan. In combination with a pseudo phase cycle, the polarization transfer method used here also enables efficient suppression of unwanted background signals.

Background suppressed magnetization transfer MRI.

Up to 30% of the hydrogen atoms in brain tissue are part of molecules ("semisolids") other than water. In MRI, their magnetization is typically not observed directly, but can influence the water magnetization through magnetization transfer (MT). Comparison of MRI scans differentially sensitized to MT allows estimation of the semisolid fraction and potential changes with disease. Here, we present an approach designed to improve this estimate by measuring the size of the MT effect in a single scan. A stimulated echo sequence was used to generate a spatial pattern in the longitudinal water magnetization, which was then given time to exchange with semisolids. After saturating the remaining water magnetization, reverse exchange was allowed to partly re-establish the original water magnetization pattern. The third excitation pulse then formed a stimulated echo out of this pattern. MT data were obtained on 10 human subjects at 7 T with varying exchange times. The images showed the expected time dependence of signal associated with the forward and reverse exchange processes. Excellent suppression of non-exchanging background signal was achieved. As expected, this suppression came at the price of a substantial reduction in exchange-related signal (by ~75% compared to the signal in saturation recovery MT), in part because of the reliance on a 2-step exchange process. The results demonstrate an MT signal can be observed in a single acquisition without subtraction. This may be advantageous for MT measurements when signal instabilities related to motion and physiological variations exceed thermal noise sources.

An Exonuclease I-Assisted Silver-Metallized Electrochemical Aptasensor for Ochratoxin A Detection.

Ochratoxin A (OTA)-a mycotoxin produced by Aspergillus and Penicillium fungi-is a carcinogen and common trace contaminant in agricultural and processed food products. As consumption is detrimental to human and animal health, regular product monitoring is vital, and highly sensitive and portable OTA sensors are necessary in many circumstances. Herein, we report an ultrasensitive, electroanalytical aptasensor for precise determination of OTA at trace levels. The sensor leverages a DNA aptamer to capture OTA and silver metallization as a signal enhancer. Exonuclease I is used to digest unbound aptamers, engendering excellent background signal suppression and sensitivity enhancements. Efficient optimization of assay conditions is achieved using central composite design (CCD), allowing rapid evaluation of both the electrode and square wave voltammetry parameter space. The sensor exhibits excellent analytical performance, with a concentration limit of detection of 0.7 pg mL-1, a limit of quantitation of 2.48 pg mL-1, and a linear dynamic range ( R2 = 0.968) of over 6 orders of magnitude (between 1 pg mL-1 and 0.1 μg mL-1). Direct comparison with ultraperformance liquid chromatography (UPLC) indicates excellent analytical performance for standard solutions ( R2 = 0.995) and spiked beer samples ( R2 = 0.993), with almost quantitative recovery and less than 5% relative standard deviation (RSD).

MRI for prostate cancer: can computed high b-value DWI replace native acquisitions?

To compare computed high b-value diffusion-weighted images (c-DWI) derived from low b-value DWI images and acquired high b-value DWI (a-DWI), in overall image quality and prostate cancer detection rate. A total of 124 consecutive men with suspected prostate cancer (PCa) underwent diagnosis prostate MRI on a 3.0T MR system using a 32-channel phased-array torso coil. Among them, 63 underwent prostate biopsy. MRI protocol included 3DT2w images, high resolution Fov Optimized and Constrained Undistorted Single-Shot (FOCUS™) DWI images with b-values of 100, 400, 800, and 2000s/mm2 and dynamic contrast enhanced images. C-DWI images (2000 and 2500s/mm2) were derived from the three lower acquired b-value DWI images using a mono-exponential diffusion decay. C-DWI and acquired high b-value DWI (a-DWI) (2000s/mm2) were compared for image quality (background signal suppression, anatomic clarity, ghosting, distortion) and tumor conspicuity by four radiologists. C-DWIs demonstrated higher rating than a-DWIs for overall image quality despite worsened ghosting. In patients with a biopsy, similar detection rate was observed while conspicuity was better with c-DWI (p < 0.001). Non-acquisition of high b-value a-DWI reduced total acquisition time by 220s per patient. C-DWI provides a substantial reduction in acquisition time while maintaining comparable prostate cancer detection rate and improving global image quality. • Computed DWI improves global quality of prostate MRI. • Computed DWI improves analysis of DWI images with decrease acquisition time. • Computed DWI provides greater background suppression of parenchyma and improves conspicuity of suspicious lesion.

A Label-Free Fluorescent DNA Machine for Sensitive Cyclic Amplification Detection of ATP.

In this study, a target recycled amplification, background signal suppression, label-free fluorescent, enzyme-free deoxyribonucleic acid (DNA) machine was developed for the detection of adenosine triphosphate (ATP) in human urine. ATP and DNA fuel strands (FS) were found to trigger the operation of the DNA machine and lead to the cyclic multiplexing of ATP and the release of single stranded (SS) DNA. Double-stranded DNA (dsDNA) was formed on graphene oxide (GO) from the combination of SS DNA and complementary strands (CS′). These double strands then detached from the surface of the GO and in the process interacted with PicoGreen dye resulting in amplifying fluorescence intensity. The results revealed that the detection range of the DNA machine is from 100 to 600 nM (R2 = 0.99108) with a limit of detection (LOD) of 127.9 pM. A DNA machine circuit and AND-NOT-AND-OR logic gates were successfully constructed, and the strategy was used to detect ATP in human urine. With the advantage of target recycling amplification and GO suppressing background signal without fluorescent label and enzyme, this developed strategy has great potential for sensitive detection of different proteins and small molecules.