Abstract:Herein, rigid 3D DNA nanopillar was used to investigate the influence of spatial organization on the cascade activity in multienzymes system, realizing controllable regulation of mimic enzyme ratio and spacing...
“…1 B). These results were entirely consistent with the previous report [ 24 ], indicating the successful synthesis of AuNPs-Ty. Fig.…”
Section: Resultssupporting
confidence: 93%
“…Recently, our group proposed a cytosensor that used HRP to catalyze the deposition of tyramine-modified electroactive reporters on tumor cells, exhibiting significantly enhanced sensitivity [ 23 ]. Nevertheless, HRP has suffered from complicated purification processes and poor chemical stability due to the intrinsic characters of nature enzymes [ 24 ], which compromise the clinical applicability of TSA-based strategies. G-quadruplex-hemin (G4-hemin), an HRP-mimicking DNAzyme with excellent catalytic performance, has been widely applied in biosensing owing to its easy synthesis, high stability, and low requirement for reaction conditions [ 25 , 26 ].…”
Human epidermal growth factor receptor 2 (HER2)-positive exosomes play an extremely important role in the diagnosis and treatment options of breast cancers. Herein, based on the reformative tyramine signal amplification (TSA) enabled by molecular aptamer beacon (MAB) conversion, a label-free surface plasmon resonance (SPR) biosensor was proposed for highly sensitive and specific detection of HER2-positive exosomes. The exosomes were captured by the HER2 aptamer region of MAB immobilized on the chip surface, which enabled the exposure of the G-quadruplex DNA (G4 DNA) that could form peroxidase-like G4-hemin. In turn, the formed G4-hemin catalyzed the deposition of plentiful tyramine-coated gold nanoparticles (AuNPs-Ty) on the exosome membrane with the help of H2O2, generating a significantly enhanced SPR signal. In the reformative TSA system, the horseradish peroxidase (HRP) as a major component was replaced with nonenzymic G4-hemin, bypassing the defects of natural enzymes. Moreover, the dual-recognition of the surface proteins and lipid membrane of the desired exosomes endowed the sensing strategy with high specificity without the interruption of free proteins. As a result, this developed SPR biosensor exhibited a wide linear range from 1.0 × 104 to 1.0 × 107 particles/mL. Importantly, this strategy was able to accurately distinguish HER2-positive breast cancer patients from healthy individuals, exhibiting great potential clinical application.
Graphical Abstract
“…1 B). These results were entirely consistent with the previous report [ 24 ], indicating the successful synthesis of AuNPs-Ty. Fig.…”
Section: Resultssupporting
confidence: 93%
“…Recently, our group proposed a cytosensor that used HRP to catalyze the deposition of tyramine-modified electroactive reporters on tumor cells, exhibiting significantly enhanced sensitivity [ 23 ]. Nevertheless, HRP has suffered from complicated purification processes and poor chemical stability due to the intrinsic characters of nature enzymes [ 24 ], which compromise the clinical applicability of TSA-based strategies. G-quadruplex-hemin (G4-hemin), an HRP-mimicking DNAzyme with excellent catalytic performance, has been widely applied in biosensing owing to its easy synthesis, high stability, and low requirement for reaction conditions [ 25 , 26 ].…”
Human epidermal growth factor receptor 2 (HER2)-positive exosomes play an extremely important role in the diagnosis and treatment options of breast cancers. Herein, based on the reformative tyramine signal amplification (TSA) enabled by molecular aptamer beacon (MAB) conversion, a label-free surface plasmon resonance (SPR) biosensor was proposed for highly sensitive and specific detection of HER2-positive exosomes. The exosomes were captured by the HER2 aptamer region of MAB immobilized on the chip surface, which enabled the exposure of the G-quadruplex DNA (G4 DNA) that could form peroxidase-like G4-hemin. In turn, the formed G4-hemin catalyzed the deposition of plentiful tyramine-coated gold nanoparticles (AuNPs-Ty) on the exosome membrane with the help of H2O2, generating a significantly enhanced SPR signal. In the reformative TSA system, the horseradish peroxidase (HRP) as a major component was replaced with nonenzymic G4-hemin, bypassing the defects of natural enzymes. Moreover, the dual-recognition of the surface proteins and lipid membrane of the desired exosomes endowed the sensing strategy with high specificity without the interruption of free proteins. As a result, this developed SPR biosensor exhibited a wide linear range from 1.0 × 104 to 1.0 × 107 particles/mL. Importantly, this strategy was able to accurately distinguish HER2-positive breast cancer patients from healthy individuals, exhibiting great potential clinical application.
Graphical Abstract
“…21−23 However, the random distribution of enzymes in conventional methods also suffers from the chaotic enzyme active sites and inappropriate distance between enzymes, leading to low utilization efficiency of intermediates and restricted catalytic efficiency. 24 Thus, it is inevitable to find a scaffold for loading the enzymes more orderly in spatial arrangement to improve the cascaded catalytic efficiency. In recent years, some DNA nanostructures have been adopted to study the spatial arrangement, which not only possess controllability and biocompatibility but also adjust the distance on the nanoscale because of its precise addressability and structural programmability.…”
Section: ■ Introductionmentioning
confidence: 99%
“…Enzyme cascade reactions play a significant role in the process of signal amplification, which amplifies the signal response exponentially and further realizes sensitive detection of targets. − However, the random distribution of enzymes in conventional methods also suffers from the chaotic enzyme active sites and inappropriate distance between enzymes, leading to low utilization efficiency of intermediates and restricted catalytic efficiency . Thus, it is inevitable to find a scaffold for loading the enzymes more orderly in spatial arrangement to improve the cascaded catalytic efficiency.…”
Herein,
a novel two-dimensional ladder-like DNA nanostructure (LDN)-mediated
cascade catalytic nanomachine (LDN–CCN) with a higher catalytic
efficiency beyond those of a conventional one-dimensional hybrid chain
reaction (HCR) nanostructure-mediated CCN was constructed and applied
to design an electrochemical biosensing platform with first-rank performance
for ultrasensitive detection of target miRNA-21. First, output DNA
S1′ and S2′ were produced through the DNAzyme recycle
amplification when the target miRNA-21 existed. Then, the controllable
LDN–CCN was constructed on S1–S2 modified electrodes
by the subsequent reaction triggered by S1′ and S2′
with H1-AuNPs, H2, H3-AuNPs, and H4 with the assistance of K+ and hemin, in which the hemin/G-quadruplexes could produce a prominent
electrochemical signal response to the substrate glucose. The best
performance of cascade catalysis was acquired when the distance of
Au nanoparticles (glucose oxidase-like activity) modified on H1 and
H3 and hemin/G-quadruplexes (peroxidase-like activity) formed by the
sticky ends of H2 and H4 was roughly 9 nm (27 bp) in LDN–CCN.
The constructed electrochemical platform realized the sensitive detection
of target miRNA-21 with the linear range from 100 aM to 10 nM and
with a detection limit as low as 48.5 aM, which provided novel insights
to explore the new functional DNA nanostructure and well-performing
mimic enzyme cascade catalytic platforms for applications in biological
fields and early diagnosis of diseases.
“…Our group proposed a cytosensor that used HRP to catalyze the deposition of tyraminemodi ed electroactive reporters on tumor cells [25]. Nevertheless, HRP has been suffered from complicated puri cation processes and poor chemical stability due to the intrinsic characters of nature enzymes [26], which compromise the clinical applicability of TSA-based strategies. G-quadruplex-hemin (G4-hemin), an HRP-mimicking DNAzyme with excellent catalytic performance, has been widely applied in the biosensing owing to its easy synthesis, high stability, and low requirement for reaction conditions [27,28].…”
HER2-positive exosomes play an extremely important role in the diagnosis and treatment options of breast cancers. Herein, based on the reformative tyramine signal amplification (TSA) enabled by molecular aptamer beacon (MAB) conversion, a label-free surface plasmon resonance (SPR) biosensor was proposed for highly sensitive and specific detection of HER2-positive exosomes. The exosomes were captured by the HER2 aptamer region of MAB immobilized on the chip surface, which enabled the exposure of the G4 DNA that could form peroxidase-like G4-hemin. In turn, the formed G4-hemin catalyzed the deposition of plentiful tyramine-coated AuNPs (AuNPs-Ty) on the exosome membrane with the help of H2O2, generating significantly enhanced SPR signal. In the reformative TSA system, the horseradish peroxidase (HRP) as a major component was replaced with nonenzymic G4-hemin, bypassing the defects of nature enzymes. Moreover, the dual-recognition of the surface proteins and lipid membrane of the desired exosomes endowed the sensing strategy with high specificity without the interruption of free proteins. As a result, this developed SPR biosensor exhibited a wide linear range from 1.0 × 104 to 1.0 × 107 particles/mL. Importantly, this strategy was able to accurately distinguish HER2-positive breast cancer patients from healthy individuals, exhibiting great potential clinical application.
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