Quench-Shield Ratiometric Upconversion Luminescence Nanoplatform for Biosensing.

Upconversion nanoparticles (UCNPs) possess several unique features, but they suffer from surface quenching effects caused by the interaction between the UCNPs and fluorophore. Thus, the use of UCNPs for target-induced emission changes for biosensing and bioimaging has been challenging. In this work, fluorophore and UCNPs are effectively separated by a silica transition layer with a thickness of about 4 nm to diminish the surface quenching effect of the UCNPs, allowing a universal and efficient luminescence resonance energy transfer (LRET) ratiometric upconversion luminescence nanoplatform for biosensing applications.

Biostable L-DNAzyme for Sensing of Metal Ions in Biological Systems.

DNAzymes, an important type of metal ion-dependent functional nucleic acid, are widely applied in bioanalysis and biomedicine. However, the use of DNAzymes in practical applications has been impeded by the intrinsic drawbacks of natural nucleic acids, such as interferences from nuclease digestion and protein binding, as well as undesired intermolecular interactions with other nucleic acids. On the basis of reciprocal chiral substrate specificity, the enantiomer of D-DNAzyme, L-DNAzyme, could initiate catalytic cleavage activity with the same achiral metal ion as a cofactor.

Using aptamers to elucidate esophageal cancer clinical samples.

The epithelial cell adhesion molecule (EpCAM) is closely correlated with the occurrence and development of various cancers of epithelial origin. This study tested, for the first time, the ability of EpCAM aptamer SYL3C to detect EpCAM expression in 170 cases of esophageal cancer (EC) and precancerous lesions, as well as 20 cases of EC series samples, using immunofluorescence imaging analysis. Corresponding antibodies were used as control.

Catalytic self-assembly of a DNA dendritic complex for efficient gene silencing.

A catalytic self-assembled DNA dendritic complex was herein reported and used for siRNA-based gene silencing. This kind of one-pot DNA dendrimer can be conveniently prepared as needed, and it was demonstrated to have better silencing efficiency and lower cytotoxicity than commercial cationic lipid transfection agents.

Aptamers: versatile molecular recognition probes for cancer detection.

In the past two decades, aptamers have emerged as a novel class of molecular recognition probes comprising uniquely-folded short RNA or single-stranded DNA oligonucleotides that bind to their cognate targets with high specificity and affinity. Aptamers, often referred to as "chemical antibodies", possess several highly desirable features for clinical use. They can be chemically synthesized and are easily conjugated to a wide range of reporters for different applications, and are able to rapidly penetrate tissues.

Development of a panel of DNA Aptamers with High Affinity for Pancreatic Ductal Adenocarcinoma.

Pancreatic cancer costs nearly 40,000 lives in the U.S. each year and has one of the lowest survival rates among cancers.

A label-free DNAzyme fluorescence biosensor for amplified detection of Pb(2+)-based on cleavage-induced G-quadruplex formation.

DNAzyme-based catalytic beacons have been widely studied for both in vivo and in vitro molecular detection. However, only a few label-free catalytic beacons with excellent analytical performance have been reported so far. In this work, by combining a catalytic DNAzyme for amplified sensing through enzymatic turnover with cleavage-induced G-quadruplex formation, a label-free DNAzyme biosensor was developed for amplified "turn-on" fluorescence detection of Pb(2+) with a detection limit of 3nM.

Aptamers Selected by Cell-SELEX for Molecular Imaging.

Conventional diagnostics for cancer rely primarily on anatomical techniques. However, these techniques cannot monitor the changes at the molecular level in normal cells, which possibly signal the onset of cancer at its very earliest stages. For accurate prediction of the carcinogenesis at the molecular level, targeting ligands have been used in combination with imaging probes to monitor this biological process.

Cancer biomarker discovery using DNA aptamers.

Biomarkers are signature molecules able to indicate specific physiological states of cells. Identification of reliable biomarkers is essential for early diagnosis and adaptive treatment of diseases, especially cancer. Aptamers are single-stranded oligonucleotides generated by an in vitro screening method called Systematic Evolution of Ligands by Exponential Enrichment (SELEX).

Ionic Functionalization of Hydrophobic Colloidal Nanoparticles To Form Ionic Nanoparticles with Enzymelike Properties.

Inorganic colloidal nanoparticles (NPs) stabilized by a layer of hydrophobic surfactant on their surfaces have poor solubility in the aqueous phase, thus limiting their application as biosensors under physiological conditions. Here we report a simple model to ionize various types of hydrophobic colloidal NPs, including FePt, cubic Fe3O4, Pd, CdSe, and NaYF4 (Yb 30%, Er 2%, Nd 1%) NPs, to multicharged (positive and negative) NPs via ligand exchange. Surfaces of neutral hydrophobic NPs were converted to multicharged ions, thus making them soluble in water.

A FRET-based ratiometric two-photon fluorescent probe for dual-channel imaging of nitroxyl in living cells and tissues.

A FRET-based two-photon fluorescent probe, , which exhibited a fast and high selective ratiometric response to nitroxyl, was first proposed. was successfully applied to two-photon dual-channel imaging of nitroxyl in living cells and tissues with less cross-talk between channels and satisfactory deep-tissue imaging depth.

A Synthetic Aptamer-Drug Adduct for Targeted Liver Cancer Therapy.

AS1411 (previously known as AGRO100) is a 26 nucleotide guanine-rich DNA aptamer which forms a guanine quadruplex structure. AS1411 has shown promising utility as a treatment for cancers in Phase I and Phase II clinical trials without causing major side-effects. AS1411 inhibits tumor cell growth by binding to nucleolin which is aberrantly expressed on the cell membrane of many tumors.

Efficient Two-Photon Fluorescent Probe for Nitroreductase Detection and Hypoxia Imaging in Tumor Cells and Tissues.

Hypoxia plays an important role in tumor progression, and the development of efficient methods for monitoring hypoxic degree in living systems is of great biomedical importance. In the solid tumors, the nitroreductase level is directly corresponded with the hypoxic status. Many one-photon excited fluorescent probes have been developed for hypoxia imaging in tumor cells via the detection of nitroreductase level.

Entropy Beacon: A Hairpin-Free DNA Amplification Strategy for Efficient Detection of Nucleic Acids.

Here, we propose an efficient strategy for enzyme- and hairpin-free nucleic acid detection called an entropy beacon (abbreviated as Ebeacon). Different from previously reported DNA hybridization/displacement-based strategies, Ebeacon is driven forward by increases in the entropy of the system, instead of free energy released from new base-pair formation. Ebeacon shows high sensitivity, with a detection limit of 5 pM target DNA in buffer and 50 pM in cellular homogenate.

Progress and Challenges in Developing Aptamer-Functionalized Targeted Drug Delivery Systems.

Aptamers, which can be screened via systematic evolution of ligands by exponential enrichment (SELEX), are superior ligands for molecular recognition due to their high selectivity and affinity. The interest in the use of aptamers as ligands for targeted drug delivery has been increasing due to their unique advantages. Based on their different compositions and preparation methods, aptamer-functionalized targeted drug delivery systems can be divided into two main categories: aptamer-small molecule conjugated systems and aptamer-nanomaterial conjugated systems.

Single Nanoparticle to 3D Supercage: Framing for an Artificial Enzyme System.

A facile strategy has been developed to fabricate Cu(OH)2 supercages (SCs) as an artificial enzyme system with intrinsic peroxidase-mimic activities (PMA). SCs with high catalytic activity and excellent recyclability were generated via direct conversion of amorphous Cu(OH)2 nanoparticles (NPs) at room temperature. More specifically, the process that takes a single nanoparticle to a 3D supercage involves two basic steps.

STIP is a critical nuclear scaffolding protein linking USP7 to p53-Mdm2 pathway regulation.

The ubiquitin-specific protease USP7 stabilizes both Mdm2 and p53 by removing ubiquitins, hence playing an important enzymatic role in the p53-Mdm2 pathway. However, it is poorly understood how USP7 executes its dual-stabilization effect on Mdm2 and p53 in cellular context. Here, we report that STIP is a novel macromolecular scaffold that links USP7 to the p53-Mdm2 pathway.

Self-Assembled DNA Immunonanoflowers as Multivalent CpG Nanoagents.

Synthetic unmethylated cytosine-guanine (CpG) oligodeoxynucleotides are immunostimulatory motifs that have shown promise as vaccines or adjuvants for diseases such as cancers and infectious diseases. In the present work, novel immuno-nanoflowers (NFs), self-assembled from long DNA integrated with tandem CpG through rolling circle replication, were developed for efficient CpG delivery and protection from nuclease degradation. In a model of macrophage-like cells, the CpG NFs proved to be potent immunostimulators by triggering the proliferation of these immune cells, which, in turn, secreted immunostimulatory cytokines, including tumor necrosis factor α, interleukin-6, and interleukin-10.

A novel AgNP/DNA/TPdye conjugate-based two-photon nanoprobe for GSH imaging in cell apoptosis of cancer tissue.

In the present study, a novel two-photon nanoprobe has been developed and successfully applied in glutathione (GSH) imaging in cell apoptosis of cancer tissue.

A cascade reaction network mimicking the basic functional steps of adaptive immune response.

Biological systems use complex 'information-processing cores' composed of molecular networks to coordinate their external environment and internal states. An example of this is the acquired, or adaptive, immune system (AIS), which is composed of both humoral and cell-mediated components. Here we report the step-by-step construction of a prototype mimic of the AIS that we call an adaptive immune response simulator (AIRS).

Preparation and biomedical applications of programmable and multifunctional DNA nanoflowers.

We describe a comprehensive protocol for the preparation of multifunctional DNA nanostructures termed nanoflowers (NFs), which are self-assembled from long DNA building blocks generated via rolling-circle replication (RCR) of a designed template. NF assembly is driven by liquid crystallization and dense packaging of building blocks, which eliminates the need for conventional Watson-Crick base pairing. As a result of dense DNA packaging, NFs are resistant to nuclease degradation, denaturation or dissociation at extremely low concentrations.

STIP overexpression confers oncogenic potential to human non-small cell lung cancer cells by regulating cell cycle and apoptosis.

Sip1/tuftelin-interacting protein (STIP), a multidomain nuclear protein, is a novel factor associated with the spliceosome, yet its role and molecular function in cancer remain unknown. In this study, we show, for the first time, that STIP is overexpressed in non-small cell lung cancer (NSCLC) tissues compared to adjacent normal lung tissues. The depletion of endogenous STIP inhibited NSCLC cell proliferation in vitro and in vivo, caused cell cycle arrest and induced apoptosis.

Effects of human menopausal gonadotropin on zona pellucida and pregnancy outcomes of ovarian stimulation protocols.

Background: Human menopausal gonadotropin (hMG) has contributed many improvements to human assisted reproduction. However, effects of hMG on oocyte development and clinical results remain controversial.

Objective: This study was conducted to investigate the effects of hMG on the zona pellucida of oocytes, as well as clinical results in superovulation treatment.

Direct Visualization of Walking Motions of Photocontrolled Nanomachine on the DNA Nanostructure.

A light-driven artificial molecular nanomachine was constructed based on DNA scaffolding. Pyrene-modified walking strands and disulfide bond-connected stator strands, employed as anchorage sites to support walker movement, were assembled into a 2D DNA tile. Pyrene molecules excited by photoirradiation at 350 nm induced cleavage of disulfide bond-connected stator strands, enabling the DNA walker to migrate from one cleaved stator to the next on the DNA tile.

Facile Phase Transfer and Surface Biofunctionalization of Hydrophobic Nanoparticles Using Janus DNA Tetrahedron Nanostructures.

Hydrophobic nanoparticles have shown substantial potential for bioanalysis and biomedical applications. However, their use is hindered by complex phase transfer and inefficient surface modification. This paper reports a facile and universal strategy for phase transfer and surface biofunctionalization of hydrophobic nanomaterials using aptamer-pendant DNA tetrahedron nanostructures (Apt-tet).