Detection Of Telomerase Activity Research Articles

Nuclear-Shell Biopolymers Initiated by Telomere Elongation for Individual Cancer Cell Imaging and Drug Delivery.

Here, we propose a strategy for unique nuclear-shell biopolymers initiated by telomere elongation for telomerase activity detection and precise drug delivery to individual cancer cells. Telomerase-triggered DNA rolling-circle amplification (RCA) is used to assemble nuclear-shell biopolymers with signal molecules for selective cancer cell recognition and efficient drug delivery to targeted individual cells. This strategy not only should allow the creation of clustered 5-carboxyfluorescein (FAM)-fluorescence spots in response to human-telomerase activity in individual cancer cells but also could efficiently deliver drugs to reduce the undesired death of healthy cells. These findings offer new opportunities to improve the efficacy of cancer cell imaging and therapy.

Label-free molecular beacons-based cascade amplification DNA machine for sensitive detection of telomerase activity

Sensitive detection of telomerase activity is critical to cancer diagnosis, screening of anticancer drugs and evaluation of cancer therapy. Herein, a label-free molecular beacons-based DNA machine was developed for sensitive detection of telomerase activity. The DNA machine consisted of T7 exonuclease (T7 Exo), label-free recognition molecular beacon (RMB) and signal molecular beacon (SMB) with projecting 5′-terminuses, which can protect RMB and SMB from being digested by T7 Exo. Firstly, telomerase elongated telomerase substrate (TS) primer, generating a telomerase elongation production (TEP) with tandem repeats (TTAGGG)n. Next, TEP activated the DNA machine by hybridizing with RMB, unfolding RMB with a recessed 5′-terminus, making RMB deprotection from T7 Exo. Then T7 Exo-assisted cycling cleavage was incurred, releasing intact TEP and numerous DNA fragments (trigger DNA), which got recycling I. Subsequently, trigger DNA specifically opened SMB and was recycled by T7 Exo, liberating multiple G-quadruplex (G4) structures, which got recycling II. Finally, TEP and the liberative G4 structures strongly interacted with N-methyl-mesoporphyrin IX (NMM), yielding a significantly enhanced fluorescence together. In this way, per telomerase-mediated elongation event was efficiently converted into the greatly amplified fluorescence signals. Telomerase activity in crude HeLa cells extracts equivalent to 50 cells/mL was successfully measured with a linear range from 50 cells/mL to 2000 cells/mL. Besides, the strategy was also successfully used to assay the inhibition effect of a telomerase-inhibiting drug, demonstrating the strategy holds the potential to screen telomerase inhibitors.

Telomerase Activity Detection with Amplification-Free Single Molecule Stochastic Binding Assay.

Because the elongation of telomeres has been associated with tumorigenesis, it is of great interest to develop rapid and high-confidence telomerase activity detection methods for disease diagnosis. Currently, amplification-based strategies have been extensively explored for telomerase detection in vitro and in vivo. However, amplification is typically associated with poor reproducibility and high background, which hamper further applications of the strategies, particularly for real sample assays. Here, we demonstrate a new amplification-free single molecule imaging method for telomerase activity detection in vitro based on nucleic acid stochastic binding with total internal reflection fluorescence microscopy. The dynamic stochastic binding of a short fluorescent DNA probe with a genuine target yields a distinct kinetic signature from the background noise, allowing us to identify telomerase reaction products (TRPs) at the single molecule level. A limit-of-detection as low as 0.5 fM and a dynamic range of 0.5-500 fM for TRP detection were readily achieved. With this method, telomerase extracted from cancer cells was determined with sensitivity down to 10 cells. Moreover, the length distribution of TRPs was also determined by multiple stochastic probing, which could provide deep insight into the mechanistic study of telomerase catalysis.

Ultrasensitive Assay for Telomerase Activity via Self-Enhanced Electrochemiluminescent Ruthenium Complex Doped Metal-Organic Frameworks with High Emission Efficiency.

Here, an ultrasensitive "off-on" electrochemiluminescence (ECL) biosensor was proposed for the determination of telomerase activity by using a self-enhanced ruthenium polyethylenimine (Ru-PEI) complex doped zeolitic imidazolate framework-8 (Ru-PEI@ZIF-8) with high ECL efficiency as an ECL indicator and an enzyme-assisted DNA cycle amplification strategy. The Ru-PEI@ZIF-8 nanocomposites were synthesized by self-enhanced Ru-PEI complex doping during the growth of zeolitic imidazolate framework-8 (ZIF-8), which presented high ECL efficiency and excellent stability. Furthermore, owing to the porosity of Ru-PEI@ZIF-8, the self-enhanced Ru-PEI complex in the outer layer and inner layer of self-enhanced Ru-PEI@ZIF-8 could be excited by electrons causing the utilization ratio of the self-enhanced ECL materials to be remarkably increased. To further improve the sensitivity of the proposed biosensor, the telomerase activity signal was converted into the trigger DNA signal which was further amplified by an enzyme-assisted DNA recycle-amplification strategy. The proposed ECL biosensor presented great performance for telomerase activity detection from 5 × 101 to 106 Hela cells with a detection limit of 11 cells. Moreover, this method was applied in the detection of telomerase activity from cancer cells treated with an anticancer drug, which indicated the proposed method held potential application value as an evaluation tool in anticancer drug screening.

Construction of AIEgens-Based Bioprobe with Two Fluorescent Signals for Enhanced Monitor of Extracellular and Intracellular Telomerase Activity.

Detections of telomerase activity in vitro and in living cells are of great importance for clinical diagnosis of cancer. In this work, an AIEgens-based bioprobe with two fluorescent signals for enhanced monitor of extracellular and intracellular telomerase activity is designed. After addition of telomerase, two positively charged AIEgens (Silole-R and TPE-H) bind to quencher group labeled primer (QP) and the extension repeated units, leading enhancement of two telomerase-triggered fluorescent signals. Furthermore, by combination the wider linear range in vitro and lower background in living cells imaging, the bioprobe is used to detect telomerase extracted from various cell lines (MCF-7, HeLa, E-J, and HLF), 50 bladder cancer patients' urine samples, 10 normal people's urine samples, and also applied in mapping telomerase activity inside living cells (MCF-7, HeLa, MDA-MB-231, and HT1080). The results show that this well-designed strategy can successfully detect telomerase activity in vitro and in living cells with high sensitivity, indicating the potential application of this method in cancer cells bioimaging and clinical cancer diagnosis.

Advances in the detection of telomerase activity using isothermal amplification.

Telomerase plays a significantly important role in keeping the telomere length of a chromosome. Telomerase overexpresses in nearly all tumor cells, suggesting that telomerase could be not only a promising biomarker but also a potential therapeutic target for cancers. Therefore, numerous efforts focusing on the detection of telomerase activity have been reported from polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (TRAP) assays to PCR-free assays such as isothermal amplification in recent decade. In this review, we highlight the strategies for the detection of telomerase activity using isothermal amplification and discuss some of the challenges in designing future telomerase assays as well.

Evaluation of intracellular telomerase activity through cascade DNA logic gates.

Telomerase plays a vital role in cancer and aging, and telomerase activity detection has drawn great attention recently. However, a feasible in situ imaging system for intracellular telomerase is still a challenge. Here, we develop a novel approach to image intracellular telomerase activity using DNA-based computation. A cascade nucleic acid logic gate that responded to intracellular telomerase was constructed. A telomerase substrate (TS) probe, extended by intracellular telomerase, worked as an input to initiate computation cascades. In this way, intracellular telomerase could be clearly indicated by fluorophore labeled nucleic acids as the output. Through one-step incubation, evaluation of the intracellular telomerase activity for a HeLa cell line and the ability to differentiate cancer cells from normal cells could be realized. Furthermore, the response of intracellular telomerase activity to a telomerase-inhibiting model drug was observed using the proposed method. Thus, this intracellular telomerase computation device will allow improvements in studying the relationship between telomerase and cancer, and may help to develop telomerase inhibitors. This finding also expands the applications of DNA computational techniques in cells.

Bioresponsive-controlled release of methylene blue from magnetic mesoporous silica from the electrochemical detection of telomerase activity.

An electrochemical sensing platform was designed to monitor telomerase activity in HeLa cells, using bioresponsively controlled cargo release from magnetic mesoporous silica nanocontainers (MMSNs). The aminated MMSNs were first synthesized by a wet-chemistry method, then methylene blue (indicator) molecules were loaded into the pores with the aid of specifically designed wrapping DNA strands, and then the wrapping DNA-gated MMSNs were immobilized on a magnetic removable screen-printing carbon electrode. Upon target telomerase and dNTP introduction into the detection cell, the wrapping DNA strands on the MMSNs were prolonged to form rigid hairpin-like DNA structures, thus resulting in the dissociation of wrapping DNA strands from the MMSNs. Thereafter, the loaded methylene blue with redox activity was released out from the pores, thereby causing the increase in the electrochemical signal relative to the background signal. Under optimal conditions, an MMSN-based sensing system exhibited good voltammetric responses toward target telomerase activity within the dynamic linear range of 50-5000 cells per mL at a detection limit of 12 cells per mL in the HeLa extract. The reproducibility and generality of our strategy were acceptable by using somatic tumor cell lines. In addition, the inhibition effect of this system was also evaluated by using 3'-azido-3'-deoxythymidine as a telomerase inhibitor, receiving good results in this screening research.

An ultra-sensitive colorimetric assay for reliable visual detection of telomerase activity.

The visual detection of a disease biomarker is a promising strategy due to its simplicity and low cost, but the complexity of biological samples limits its application. Herein, a reliable and ultrasensitive colorimetric assay was proposed for detecting telomerase activity in crude cancer cell extracts. A telomerase substrate (TS) primer was immobilized onto magnetic beads (MBs) to form a MB/TS complex. In the presence of telomerase and deoxyribonucleotide triphosphates (dNTPs), the TS primer was elongated by adding multiple telomeric repeats (TTAGGG)n to the 3' end of the TS. The telomeric repeats of the elongated TS (ETS) hybridized with its short complementary DNA (cDNA) to specifically capture peroxidase onto MBs. After magnetic separation, the activity of telomerase was detected by monitoring the change in the color or absorbance of the peroxidase-catalyzed H2O2/TMB reaction. Magnetic separation greatly eliminated the non-specific interference to ensure reliability and improve the signal-to-noise (S/N) ratio. The mean telomerase activity equivalent to 5 HeLa cells and 1 HeLa cell was reliably detected with the naked eye and UV-vis spectroscopy, respectively. More importantly, the telomerase activity of 5 and 20 HeLa cells was detected via UV-vis spectroscopy and the naked eye, respectively. The differences in the telomerase activity of four carcinoma cell lines and one normal cell line were discriminated visually. Even more strikingly, the telomerase activity of 10 and 50 HeLa cells in human serum was detected by change in the absorbance and color of the TMB/H2O2 solution, respectively. Therefore, it offers an ultrasensitive and reliable colorimetric assay for the visual detection of telomerase activity, which holds promising potential to detect telomerase activity in a complex pathological sample.

A sensitive, label-free electrochemical detection of telomerase activity without modification or immobilization

Telomerase has become one of the most typical tumor marker because it is closely related to cancers. In this paper, a simple label-free electrochemical detection of telomerase activity by using methylene blue (MB) as a G-quadruplex binding probe was proposed, avoiding commonly used complex label procedures, nano-probe synthesis, complicated electrode modification, probe immobilization or signal amplification. In the presence of telomerase substrate (TS) primer, the binding of MB on primer was weak. When repeats of (TTAGGG) were extended on the TS primer under the action of telomerase, they formed multiple G-quadruplexes with the help of K+. As a result, a large amount of MB bounded to multiple G-quadruplexes because they have more strong interaction with G-quadruplexes than TS primer. As a result, the diffusion current of MB decreased sharply, which was strongly dependent on the telomerase activity. The DPV current change has a linear correlation with the logarithm of HeLa cell number in the range of 10–10,000 cells, with the detection limit of 3 cells. The high sensitivity was due to the formed multiple G-quadruplexes. Using indium tin oxide (ITO) as working electrode without modification ensured the good reproducibility of the method. The method was also simple, rapid, and has been successfully applied in the telomerase activity detection in urine with good selectivity and reproducibility, which is significant for cancer diagnosis, anticancer drugs screening, and cancer therapy evaluation.

Fluorescence Imaging of Intracellular Telomerase Activity Using Enzyme-Free Signal Amplification.

A novel enzyme-free signal amplification-based assay for highly sensitive in situ fluorescence imaging and detection of intracellular telomerase activity was developed by using a gold nanoflare probe-triggered mimic-hybridization chain reaction (mimic-HCR) coupled with a graphene oxide (GO) surface-anchored fluorescence signal readout pathway. The nanoflare probe consists of gold nanoparticles (AuNPs) functionalized with a dense shell of nucleic acid sequences by Au-S bond formation. The nucleic acid sequence is composed of three segments: a long thiol-labeled sequence (HS-DNA) and two short sequences (a telomerase primer sequence, "Primer-DNA", and an FAM-terminated reporter sequence, "Flare-DNA"), both of which are complementary to HS-DNA. The mimic-HCR system is formed by two FAM-modified hairpin sequences that are adsorbed on GO. Upon endocytosis of the AuNP/GO combinatorial probe, the Primer-DNA can be extended by intracellular telomerase at its 3' end to produce the telomeric repeated sequence, which leads to inner chain substitution and not only releases the Flare-DNA to turn on the fluorescence of FAM but also initiates the subsequent signal amplification and enrichment for the mimic-HCR system anchored on GO. The proposed approach can sensitively detect telomerase activity in living cells, distinguish normal cells from cancer cells, and monitor the change in telomerase activity in response to a telomerase inhibitor.

DNA tetrahedral scaffolds-based platform for the construction of electrochemiluminescence biosensor

Proximal metallic nanoparticles (NPs) could quench the electrochemiluminescence (ECL) emission of semiconductor quantum dots (QDs) due to Förster energy transfer (FRET), but at a certain distance, the coupling of light-emission with surface plasmon resonance (SPR) result in enhanced ECL. Thus, the modification strategies and distances control between QDs and metallic NPs are critical for the ECL intensity of QDs. In this strategy, a SPR enhanced ECL sensor based on DNA tetrahedral scaffolds modified platform was reported for the detection of telomerase activity. Due to the rigid three-dimensional structure, DNA tetrahedral scaffolds grafting on the electrode surface could accurately modulate the distance between CdS QDs and luminol labelled gold nanoparticles (L-Au NPs), meanwhile provide an enhanced spatial dimension and accessibility for the assembly of multiple L-Au NPs. The ECL intensities of both CdS QDs (−1.25V vs. SCE) and luminol (+0.33V vs. SCE) gradually increased along with the formation of multiple L-Au NPs at the vertex of DNA tetrahedral scaffolds induced by telomerase, bringing in a dual-potential ECL analysis. The proposed method showed high sensitivity for the identification of telomerase and was successfully applied for the differentiation of cancer cells from normal cells. This work suggests that DNA tetrahedral scaffolds could serve as an excellent choice for the construction of SPR-ECL system.

Development of quantum-dot-encapsulated liposome-based optical nanobiosensor for detection of telomerase activity without target amplification.

Reactivation of telomerase, which is observed in more than 85% of all known human tumours, is considered a promising tumour marker for cancer diagnosis. With respect to the biomedical importance of telomerase, we have developed a simple strategy based on liposomal fluorescent signal amplification for highly sensitive optical detection of telomerase activity using liposome-encapsulated cadmium telluride quantum dots. In this strategy, telomerase extracted from A549 cells elongated the biotinylated telomerase substrate primer, which was then immobilized on streptavidine-coated microplate wells. After the hybridization of the telomerase-elongated product with biotinylated capture probe, streptavidin was added to the assembly. In the next step, biotinylated liposome was conjugated with capture probe through streptavidin. Finally, QD-encapsulated liposomes were disrupted by Triton X-100, and the fluorescence intensity of the released QDs was measured to detect telomerase activity. The results showed that the proposed nanobiosensor was able to detect telomerase activity from as few as 10 A549 cells without the enzymatic amplification of telomerase extension products. In short, this method is not only convenient and sensitive, but also has a simple operating protocol and a wide detection range (10-5000 cells). A linear range was observed between 50 and 800 cells with a correlation coefficient of 0.982 and regression equation of y = 0.0444 x + 17.137. The proposed method is economical, more user-friendly, without error-prone PCR, with a wide detection range and simple operating protocol without the requirement for sophisticated equipment. Graphical Abstract Schematic representation of the QD-encapsulated liposome-based strategy to amplify fluorescence signal for optical detection of telomerase activity.

Nanoscaled Porphyrinic Metal-Organic Frameworks for Electrochemical Detection of Telomerase Activity via Telomerase Triggered Conformation Switch.

In this work, we designed a nanoscaled porphyrinic metal-organic framework (PorMOF) with iron porphyrin as linker and zirconium ion as node for electrochemical detection of telomerase activity. The as-prepared PorMOF was characterized with scanning electron microscopy, powder X-ray diffraction, and spectroscopic techniques and demonstrated excellent electrocatalytic activity toward O2 reduction. Sequentially, the functionalization of PorMOF with streptavidin results in a water-stable electrochemical tracer for detection of telomerase. Upon the telomerase-triggered extension, the assistant DNA 1 (aDNA1)-assistant DNA 2 (aDNA2) duplex could switch into a hairpin structure, and thus, the aDNA2 was released and then hybridized with the capture DNA. Therefore, the PorMOF@SA tracer could be introduced on the electrode surface via biotin-streptavidin recognition, leading to the strong electrochemical signal for readout. The developed approach displayed desirable dynamic range and limitation of detection down to 30 HeLa cells mL-1. The telomerase activity was 2.2 × 10-11 IU in a single HeLa cell with good reproducibility and stability. The nanoscaled porphyrinic MOF provided a powerful platform for electrochemical signal transduction and had a promising application in the determination of various biomolecules.

A simple, fast, label-free colorimetric method for detection of telomerase activity in urine by using hemin-graphene conjugates

Telomerase, a widely accepted cancer biomarker for early cancer diagnostics, is considered as an important therapeutic target. To now, it is still a challenging subject to develop a simple and sensitive strategy for telomerase activity detection. Herein, we reported a simple colorimetric strategy for label-free quantification of human telomerase activity in urine by using hemin-graphene nanomaterial (H-GNs). H-GNs possessed tailored dispersibility in the high salt concentration and highly active biomimetic oxidation catalyst property. In this strategy, H-GNs were adjusted to coagulate to appropriate degree by carefully selecting the contained NaCl amount in the presence of original TS primer. The supernatant of the solution contained few H-GNs and showed light blue color. Under the action of telomerase, TS primer was elongated with repeating sequences of (TTAGGG)n. These negatively charged DNA enhanced individual H-GNs electrostatic repulsion and resisted salt-induced H-GNs coagulation. As a result, the supernate of the corresponding solution containing more dispersed H-GNs and showed dark blue color after chromogenic reaction. Thus, telomerase activity could be quasi-quantified by naked eye and precise quantified by UV spectrometer. The proposed method has the linear range from 100 to 2300 HeLa cells/mL and the detection limit was 60 cells/mL. It has been successfully applied to detect telomerase activity in real urine samples. Obtained results were in good agreement with the clinical diagnosis. Therefore, this colorimetric approach affords simplicity, sensitivity and reliability in telomerase activity detection.

Detection of Telomerase Activity Based on the Steric Hindrance Change in the Pore of Anodic Alumina Nanochannels

It has been confirmed that telomerase are closely related to cancers. [1] Urine telomerase measurement is nondestructive compared to blood analysis and pathology tests, which is significant for cancer discovery, development and prognosis. [2] In this paper, a new method for detection of urine telomerase activity based on increment of steric hindrance in the porous anodic alumina (PAA) nanochannels was proposed. Telomerase primer (TS primer) was assembled firstly on the inner wall of PAA nanochannels. Then, under the action of active telomerase, TS primer was extend with repeat G-rich sequences (TTAGGG)n, which experienced configurational change to G-quadruplex in the presence of K+. As a result, the steric hindrance in the nanochannels changed accordingly. Telomerase activity measurement were proposed based on these steric hindrance changes. The increased anodic current, produced by ferricyanide, has a linear correlation with the HeLa cell number in the range of 10 - 5000 cells, with the detection limit of 7 cells. Compared with previously reported detection method based on the steric hindrance change in the PAA pore, the anodic change in this method is bigger because multiplex G-quadruplex formed with the action of telomerase, which was advantage to improve the detection sensitivity.[3] The method was simple and reliable, which was significant to the clinical cancer diagnosis. References ： [1] Moyzis, R. K.; Buckingham, J. M.; Cram, L. S.; Dani, M.; Deaven, L. L.; Jones, M. D.; Meyne, J.; Ratliff, R. L.; Wu, J. R. P. Natl. Acad. Sci. USA., 1988, 85, 6622-6626. [2] Wu, L.; Qu, X. G. Chem. Soc. Rev., 2015, 44, 2963-2997. [3] Yu, J. C.; Zhang, L. Q.; Xu, X.; Liu, S. Q. Anal. Chem., 2014, 86, 10741-10748.

Label-free real-time investigation of the effect of telomerase inhibitors based on quartz crystal microbalance measurement

Telomerase maintains the functions of telomeres in many eukaryotes, and is related to cell senescence, apoptosis and the immortal phenotype of cancer cells. Telomerase is a well-validated cancer target and telomerase inhibitors that are able to selectively bind to telomerase are believed to be potential drugs for clinical treatment. However, the mechanisms of these inhibitors have often been deduced by non-quantitative telomerase assay (TRAP assay), which includes a PCR step that may influence the final result. We developed a label-free real-time method to detect telomerase activity. We then investigated the inhibitory effect of two telomerase inhibitors (EGCG and stavudine) and discuss the mechanism of these inhibitors.

Label-Free Detection of Telomerase Activity in Urine Using Telomerase-Responsive Porous Anodic Alumina Nanochannels.

Telomerase is closely related to cancers, which makes it one of the most widely known tumor marker. Recently, many methods have been reported for telomerase activity measurement in which complex label procedures were commonly used. In this paper, a label-free method for detection of telomerase activity in urine based on steric hindrance changes induced by confinement geometry in the porous anodic alumina (PAA) nanochannels was proposed. Telomerase substrate (TS) primer was first assembled on the inside wall of PAA nanochannels by Schiff reaction under mild conditions. Then, under the action of telomerase, TS primer was amplified and extended to repeating G-rich sequences (TTAGGG)x, which formed multiplex G-quadruplex in the presence of potassium ions (K(+)). This configurational change led to the increment of steric hindrance in the nanochannels, resulting in the decrement of anodic current of potassium ferricyanide (K3[Fe(CN)6]). Compared with previously reported methods based on PAA nanochannels (usually one G-quadruplex formed), multiplex repeating G-quadruplex formed on one TS primer in this work. As a result, large current drop (∼3.6 μA, 36%) was obtained, which gave facility to improve the detection sensitivity. The decreased ratio of anodic current has a linear correlation with the logarithm of HeLa cell number in the range of 10-5000 cells, with the detection limit of seven cells. The method is simple, reliable, and has been successfully applied in the detection of telomerase in urine with good accuracy, selectivity and reproducibility. In addition, the method is nondestructive test compared to blood analysis and pathology tests, which is significant for cancer discovery, development, and prognosis.

Nanoparticle-Aided Amplification of Fluorescence Polarization for Ultrasensitively Monitoring Activity of Telomerase.

To realize facile and reliable analyzing telomerase activity in homogeneous, herein, for the first time, a fluorescent polarization (FP) strategy was developed for polymerase chain reaction (PCR) free monitoring activity of human telomerase at single-cell level ground on gold nanoparticle (GNP) enhancement of FP. First, thiolated telomerase substrate (TS) primer is modified to the surface of GNP via Au-S bond. In the presence of telomerase, TS primer was extended via adding hexamer repeats (GGGTTA), leading to the formation of a long elongation DNA. Several short carboxyfluorescein (FAM)-modified complementary DNA (F-cDNA) can hybridize with the hexamer repeats, resulting in a sharp increase in FP value. Because of the GNP enhancement and self-amplification of telomerase, telomerase activity accounting to one HeLa cell can be rapidly detected in homogeneous solution. Telomerase activities of various cell lines were also favorably estimated. Meanwhile, the inhibition efficiency of telomerase inhibitor was studied, which holds great potential in screening telomerase-targeted anticancer drugs as well. So, a facile method was put forward to reliably and ultrasensitively detect telomerase activity.

A highly sensitive and facile graphene oxide-based nucleic acid probe: Label-free detection of telomerase activity in cancer patient's urine using AIEgens

Molecular beacon (MB)-based sensing platforms that consist of a fluorogen-quencher pair play an important role in medical and biological researches. However, the synthesis of both fluorogen and quencher in the nucleic acid probes will increase the burden of organic synthesis works and induce the difficulties for precisely controlling the relative distance between fluorogen and quencher, which may lead to false-positive and false-negative results. In this work, initially we report a single labeled MB (FAM-MB, with carboxyfluorescein as fluorogen and without quencher) thus simplifies MBs with the aid of graphene oxide (GO) to detect telomerase activity. To further simplify this structure, namely label-free strategy, we design a facile, sensitive and selective platform using a label-free beacon (AIE-MB, without fluorogen and quencher), based on aggregation-induced emission fluorogen (silole-R). Upon the addition of telomerase, AIE-MB induced comb-like DNA structure leads to high aggregation of silole-R and thus exhibits strong fluorescence emission. By exploitation of this, we can detect telomerase with superior sensitivity and demonstrate their applications in bladder cancer diagnosis. Compared to single-labeled FAM-MB based telomerase activity assay, the label-free AIE-MB induced method could perform the sensitive detection with high signal-to-background ratio.