Detection
and imaging RNAs in live cells is in high demand. Methodology
for such a purpose is still a challenge, particularly for single RNA
detection and imaging in live cells. In this study, a type of quantum
dot (QD) nanobeacon with controllable valencies was constructed by
precisely conjugating the black hole quencher (BHQ1) and phosphorothioate
comodified DNA onto CdTe:Zn2+ QDs via a one-pot hydrothermal
method. The nanobeacon with only one conjugated DNA was used to label
and detect low-abundance nucleic acids in live cells, and single HIV-1
RNAs were detected and imaged in live HIV-1 integrated cells. Additionally,
QD nanobeacon-labeled HIV-1 genomic RNAs were encapsulated in progeny
viral particles, which can be used to track the uncoating process
of single viruses. The current study provides a platform for nucleic
acid labeling and imaging with high sensitivity, being especially
meaningful for tracking of individual RNAs in live cells.
As the blood glucose concentration is an important clinical parameter of diabetes, the rapid and effective detection of blood glucose is very significant for monitoring and managing diabetes. Here, a facile method to prepare Rox-DNA functionalized CdZnTeS quantum dots (QDs) was developed. The Rox-DNA functionalized CdZnTeS QDs were prepared by a one-pot hydrothermal method through phosphorothioate DNA bound to QDs, which were employed as a ratiometric fluorescent probe for the rapid and sensitive detection of HO and glucose. Compared with the traditional multistep construction of ratiometric fluorescent probes, this presented approach is simpler and more effective without chemical modification and complicated separation. The CdZnTeS QDs with green fluorescence is specifically sensitive to HO, while the red fluorescence of Rox is invariable. HO is the product from the oxidation of glucose catalyzed by glucose oxidase (GOx). Therefore, a facile method to detect HO and glucose with a detection limit of 0.075 μM for HO and 0.042 μM for glucose was developed. In addition, this proposed probe has been employed for the detection of glucose in human serum with a satisfactory result. Moreover, this probe has been used for visual detection, and the health and diabetics can be distinguished by the naked eye. Meanwhile, this nanoprobe is also generalizable and can be extended to the detection of many other HO-mediated analytes.
A ratiometric fluorescent sensor for mercury ions (Hg) has been constructed via covalent functionalization of silicon nanodot (SiND) with Hg-specific 6-carboxy-X-rhodamine (Rox)-tagged DNA. For the Rox-DNA functionalized SiND, the red fluorescence of Rox can be quenched by the blue-emitting SiND in the presence of Hg due to structural change in DNA, which serves as the response signal. Meawhile, the fluorescence of SiND is insensitive to Hg and acts as the reference signal. The wavelength difference in the optimal emission peak is as large as 190 nm between SiND (422 nm) and Rox (612 nm), which can efficaciously exclude the interference of the two emission peaks, and facilitates dual-color visualization of Hg ions. The biofunctionalization of SiND improves the acid-base stability of SiND significantly, which is favorable for its application in the intracellular environment. Accordingly, a sensitive, simple, precise and rapid method for tracing Hg was proposed. The limit of detection and precision of this method for Hg was 9.2 nM and 8.8% (50 nM, n = 7), respectively. The increase of Hg concentration in the range of 10-1500 nM was in accordance with linearly increase of the I/ I ratio. As for practical application, the recoveries in spiked human urine and serum samples were in the range of 81-107%. Moreover, this fluorescent nanosensor was utilized to the ratiometric detection of Hg in HeLa cells.
Detection of viruses with high sensitivity is critical
for the
prevention and treatment of the related disease. Two homogeneous target-induced
cascade amplification methods were proposed for the detection of enterovirus
71 and coxsackievirus B3. These methods both employ DNAzyme but differ
in the way in which the DNAzyme is amplified. In the hybridization
chain reaction (HCR)-based strategy, the DNAzyme is assembled by hairpin
DNA strands, while in the rolling circle amplification (RCA)-based
strategy, the DNAzyme is synthesized by the polymerase. On the basis
of the virion structure, we investigated the effects of using only
VP1-antibody or VP1-antibody and VP2-antibody on the detection. And
the combination of two kinds of antibodies was found to further improve
the performance of the detection. Subsequently, the simultaneous detection
of EV71 and CVB3 was achieved by the RCA-based strategy. And the proposed
methods were also applied in clinical samples analysis with a satisfactory
result, showing great potential for applications in virus detection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.