Chenghui Liu

Ultrasensitive Detection of microRNAs by Exponential Isothermal Amplification

tions of miRNAs have become an area of intense investigation. The detection of miRNAs is imperative for gaining a better understanding of the functions of these biomolecules and has great potential for the early diagnosis of human disease as well as the discovery of new drugs through the use

Efficient fluorescence resonance energy transfer between upconversion nanophosphors and graphene oxide: a highly sensitive biosensing platform

Graphene oxide can act as an ultrahighly efficient quencher for upconversion nanophosphors and thus, an extraordinarily sensitive biosensing platform is constructed.

Simple and sensitive detection of microRNAs with ligase chain reaction.

A simple and sensitive miRNA assay was developed with ligase chain reaction (LCR) based on specific ligation of DNA probes by using miRNAs as the templates.

One-pot synthesis of water-soluble and carboxyl-functionalized β-NaYF4:Yb,Er(Tm) upconversion nanocrystals and their application for bioimaging

Poor water-solubility and biocompatibility are the biggest obstacles for the bioapplications of upconversion nanophosphors (UCNPs). In this work, a facile solvothermal approach was developed for the one-pot synthesis of monodisperse and water-soluble β-NaYF4 UCNPs by employing poly(acrylic acid, sodium salt) (PAAs) as the capping reagent. The as-prepared UCNPs were thoroughly characterized and a possible reaction mechanism is proposed, which indicates that PAAs plays a crucial role for the shape and phase evolution of the NaYF4 UCNPs. More importantly, each multidentate PAA can tightly bind to the UCNPs surface through multiple –COO− groups, while an abundance of uncoordinated carboxyl groups on the polymer chain extend into the solution, making the UCNPs highly water-soluble. The presence of free carboxyl groups on the surfaces also facilitates the conjugation of the UCNPs with various biomolecules, which paves the way for further bio-applications. As a proof-of-concept model, transferrin was covalently linked to β-NaYF4:Yb,Er to form the transferrin–UCNPs conjugates, which have been successfully applied to the high-contrast fluorescent imaging and detection of HeLa cells. Possessing the advantages of good biocompatibility and inherent high upconversion efficiency, our directly synthesized β-NaYF4 UCNPs exhibit great potential as excellent bio-probes for in vitro or in vivo imaging, detection and diagnosis.

A versatile platform for highly sensitive detection of kinase activity based on metal ion-mediated FRET using an anionic conjugated polymer.

An anionic fluorescent conjugated polymer (PFPaa), coupled with the metal ion-mediated fluorescence resonance energy transfer, has been used to design a versatile platform for homogeneous detection of protein kinase activity.

Fluorescent water-soluble probes based on dendritic PEG substituted perylene bisimides: synthesis, photophysical properties, and live cell images

Water-soluble dyes based on dendritic polyethylene glycol (PEG)-substituted perylene bisimides were designed and synthesised. According to the distribution of hydrophilic dendritic PEGs, these dyes can be divided into two classes: (I) head–tail structured dyes, in which the hydrophobic perylene bisimides are the heads of the dyes and the hydrophilic dendritic PEG are used as the tails; (II) core–shell structured dyes, in which the hydrophobic perylene bisimides are encapsulated by the hydrophilic dendritic PEG. The aggregation behaviour and optical properties of these dyes were investigated. The two classes of water-soluble perylene bisimides show similar aggregation behaviour, optical and cytocompatibility properties. With increased dendron PEG generation, the aggregation of the PBI in an aqueous solution is completely suppressed by the hydrophilic bulky dendritic PEG groups, and the fluorescence quantum yield increases from 4% to 93%. These dendritic PEG-substituted perylene bisimides have good cytocompatibility. The head–tail structured dyes show a limited cellular uptake process. By contrast, the core–shell structured dyes are efficiently internalised by cells and accumulated in the cytoplasm.

Multiplex ligation-dependent probe amplification (MLPA) for ultrasensitive multiplexed microRNA detection using ribonucleotide-modified DNA probes

Using the ribonucleotide-modified DNA probes, multiple microRNAs can be simultaneously detected in one ligation-based PCR reaction. As low as 0.2 fM microRNA can be accurately detected with high specificity.

Highly sensitive detection of protein kinase activity using upconversion luminescent nanoparticles

An upconversion nanophosphor (UCNP)-based highly sensitive assay for the detection of protein kinase activity is developed with the assistance of Zr4+-functionalized magnetic beads.