Branched catalytic hairpin assembly is proposed for dynamic self-assembly of DNA dendrimers for signal amplification and in situ imaging of microRNAs in live cells with high sensitivity and selectivity.
The Raman probe plays an essential role in sensitive surfaceenhanced Raman scattering (SERS) assay. Here, a novel Raman probe was developed by assembling gold nanoparticles in triangular pyramid DNA (TP-Au NPs). Such probe with intense electromagnetic hot spots can provide dramatically enhanced Raman scattering. Through assembling recognition DNA on one corner of the TP-DNA, the recognition event is definite and designable. The probe was characterized through TEM, and its SERS superiority was investigated. As models, circulating tumor cells and exosomes were detected with high sensitivity and selectivity by using this probe. Meanwhile, the developed SERS probe can also perform well in real world samples.
Chemiluminescence (CL) and bioluminescence (BL) imaging technologies, which require no external light source so as to avoid the photobleaching, background interference and autoluminescence, have become powerful tools in biochemical analysis and biomedical science with the development of advanced imaging equipment. CL imaging technology has been widely applied to high-throughput detection of a variety of analytes because of its high sensitivity, high efficiency and high signal-to-noise ratio (SNR). Using luciferase and fluorescent proteins as reporters, various BL imaging systems have been developed innovatively for real-time monitoring of diverse molecules
in vivo
based on the reaction between luciferin and the substrate. Meanwhile, the kinetics of protein interactions even in deep tissues has been studied by BL imaging. In this review, we summarize
in vitro
and
in vivo
applications of CL and BL imaging for biosensing and therapy. We first focus on
in vitro
CL imaging from the view of improving the sensitivity. Then,
in vivo
CL applications in cells and tissues based on different CL systems are demonstrated. Subsequently, the recent
in vitro
and
in vivo
applications of BL imaging are summarized. Finally, we provide the insight into the development trends and future perspectives of CL and BL imaging technologies.
The
development of a theragnostic platform integrating precise
diagnosis and effective treatment is significant but still extremely
challenging. Herein, an integrated smart nanodevice composed of Au@Cu2–x
S@polydopamine nanoparticles (ACSPs)
and fuel DNA-conjugated tetrahedral DNA nanostructures (fTDNs) was
constructed, in which the ACSP nanoprobe played multiple key roles
in antitumor therapy as well as in situ monitoring
of microRNAs (miRNAs) in cancer cells. Regarding the analysis, the
ACSP probe contained two optical properties: excellent surface-enhanced
Raman scattering (SERS) enhancement and high fluorescence (FL) quenching
performance. Employing the ACSPs as the high-efficiency detection
substrate combined with the fTDN-assisted DNA walking nanomachines
as the superior amplification strategy, a SERS-FL dual-spectrum biosensor
was constructed, which achieved an ultralow background signal and
excellent sensitivity with detection limits of 0.11 pM and 4.95 aM
by FL and SERS, respectively. Moreover, the rapid FL imaging and precise
SERS quantitative detection for miRNA in cancer cells were also achieved
by dual-signal ratio strategy, improving the accuracy of diagnosis.
Regarding the therapeutic application, due to the high reactive oxygen
species generation ability and excellent photothermal conversion efficiency,
the ACSPs can also act as an all-in-one nanoagent for multimodal collaborative
tumor therapy. Significantly, both in vivo and in vitro experiments confirmed its high biological safety
and strong anticancer effect, indicating its promising theragnostic
applications.
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