Caged antisense oligodeoxynucleotides (asODNs) are synthesized by linking two ends of linear oligodeoxynucleotides using a photocleavable linker. Two of them (H30 and H40) have hairpin-like structures which show a large difference in thermal stability (Delta T(m) = 17.5 degrees C and 11.6 degrees C) comparing to uncaged ones. The other three (C20, C30 and C40) without stable secondary structures have the middle 20 deoxynucleotides complementary to 40-mer RNA. All caged asODNs have restricted opening which provides control over RNA/asODN interaction. RNase H assay results showed that 40-mer RNA digestion could be photo-modulated 2- to 3-fold upon light-activation with H30, H40, C30 and C40, while with C20, RNA digestion was almost not detectable; however, photo-activation triggered >20-fold increase of RNA digestion. And gel shift assays showed that it needed >0.04 microM H40 and 0.5 microM H30 to completely bind 0.02 microM 40-mer RNA, and for C40 and C30, it needed >0.2 microM and 0.5 microM for 0.02 microM 40-mer RNA binding. However, even 4 microM C20 was not able to fully bind the same concentration of 40-mer RNA. By simple adjustment of ring size of caged asODNs, we could successfully photoregulate their hybridization with mRNA and target RNA hydrolysis by RNase H with light activation.
Abstract Using exogenous optical triggers to continuously achieve the precise conditional control of gene expression regulation and dynamic biological processes is one of the central themes of photochemical biology of nucleic acids. Light, a quick and noninvasive stimulus, is a crucial trigger for “off‐on” photoswitching of the functions of caged molecules, including peptides and proteins, as well as oligonucleotides. In this Minireview, we mainly focus on photochemical strategies based on caged RNA oligonucleotides for optochemical control of biological functions, including caged siRNA, caged miRNA, and caged guide RNA for CRISPR/Cas9. Light‐activated RNA oligonucleotide strategies will exhibit promising applications for exploring the spatiotemporal regulation of specific gene functions and the design of stimuli‐sensitive oligonucleotide prodrugs.
Abstract Multidrug resistance (MDR) is a major obstacle limiting the effectiveness of chemotherapy against cancer. The combination strategy of chemotherapeutic agents and siRNA targeting drug efflux has emerged as an effective cancer treatment to overcome MDR. Herein, stimuli‐responsive programmable tetrahedral DNA‐RNA nanocages (TDRN) have been rationally designed and developed for dynamic co‐delivery of the chemotherapeutic drug doxorubicin and P‐glycoprotein (P‐gp) siRNA. Specifically, the sense and antisense strand sequences of the P‐gp siRNA, which are programmable bricks with terminal disulfide bond conjugation, are precisely embedded in one edge of the DNA tetrahedron. TDRN provides a stimuli‐responsive release element for dynamic control of functional cargo P‐gp siRNA that is significantly more stable than the “tail‐like” TDN nanostructures. The stable and highly rigid 3D nanostructure of the siRNA‐organized TDRN nanocages demonstrated a notable improvement in the stability of RNase A and mouse serum, as well as long‐term storage stability for up to 4 weeks, as evidenced by this study. These biocompatible and multifunctional TDRN nanocarriers with gold nanocluster‐assisted delivery (TDRN@Dox@AuNC p ) are successfully used to achieve synergistic RNAi/Chemo‐therapy in vitro and in vivo. This programmable TDRN drug delivery system, which integrates RNAi therapy and chemotherapy, offers a promising approach for treating multidrug‐resistant tumors.
To establish a sensitive and specific PCR-based method to detect Plasmodium falciparum and P. vivax in blood samples in a single amplification reaction.Malaria parasite DNA in blood was amplified by the multiplex polymerase chain reaction using two sets of primers derived from the P. f. moderately-repetitive DNA sequence and COIII gene of P.v.A 206-bp product for P. f. and a 370-bp product for P.v. were amplified by multiplex PCR, being able to detect parasitemia level as low as 5 x 10(-7) for P. f. and 1.02 x 10(-6) for P. v. and having no cross-reaction with human leucocyte DNA. A total of 783 blood samples on the filter paper collected from patients attending to malaria clinics in malaria endemic areas were detected. The positive rate of multiplex PCR was 85.8%, the misdiagnosis rate was 0, and the under-diagnosis rate was 0.1%, while these three rates of microscopic examination were 84.9%, 3.1% and 1.0%, respectively. The concordance between the two methods was 95.8%.The multiplex PCR method made the malaria detection more sensitive and specific than the microscopic examination and should be suitable for the diagnosis of malaria in mixed endemic areas, large-scale epidemiological studies, follow-up of drug treatment and donor blood screening.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Developing new nanomaterials with strong and distinctive Raman vibrations in the biological Raman-silent region (1800–2800 cm–1) were highly desirable for Raman hyperspectral detection and imaging in living cells and animals. Herein, polymeric nanoparticles with monomers containing alkyne, cyanide, azide, and carbon-deuterate were prepared as Raman-active nanomaterials (Raman beads) for bioimaging applications. Intense Raman signals were obtained due to the high density of alkyne, cyanide, azide, and carbon-deuterate in single nanoparticles, in absence of metal (such as Au or Ag) as Raman enhancers. We have developed a library of Raman beads for frequency multiplexing through the end-capping substitutions of monomers and demonstrated five-color SRS imaging of mixed nanoparticles with distinct Raman frequencies. In addition, with further surface functionalization of targeting moieties (such as nucleic acid aptamers and targeting peptides), targetable Raman beads were successfully used as probes for tumor targeting and Raman spectroscopic detection, including multicolor SRS imaging in living tumor cells and tissues with high specificity. Further in vivo studies indicated that Raman beads anchored with targeting moieties were successfully employed to target tumors in living mice after tail intravenous injection, and Raman spectral detection of tumor in live mice was achieved only through spontaneous Raman signal at the biological Raman-silent region without any signal enhancement due to a high density of Raman reporters in Raman beads. With further copolymerization of these monomers, Raman beads with supermultiplex barcoding could be readily achieved.
Real-time tracking of GGT enzymatic activity in human ovarian cancer cells is a reliable method for accurate prediction of cancer diagnosis and management.
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