Quantum-Dot-Based FRET Detection of Histone Acetyltransferase Activity

Silver coordination complex amplified electrochemiluminescence sensor for sensitive detection of coenzyme A and histone acetyltransferase activity

A kind of coenzyme A (CoA)-silver coordination complex (CoA-Ag) was in-situ developed and verified to accelerate the electron transferring and electrochemical catalysis of H₂O₂ decomposition to enhance the cathode ECL intensity of CdTe@CdS QDs. Afterward, a convenient label-free signal-on ECL approach was constructed for CoA detection with excellent specificity. In addition, the unique ECL enhancing phenomenon was also proposed to assay the enzymatic activity of histone acetyltransferases (HAT) and screen relevant inhibitors, exhibiting a promising potential in the practical application of biochemical research, disease diagnosis and drug discovery.

Chemical Biology Approaches for Investigating the Functions of Lysine Acetyltransferases

The side-chain acetylation of lysine residues in histones and non-histone proteins catalyzed by lysine acetyltransferases (KATs) represents a widespread posttranslational modification (PTM) in the eukaryotic cells. Lysine acetylation plays regulatory roles in major cellular pathways inside and outside the nucleus. In particular, KAT-mediated histone acetylation has an effect on all DNA-templated epigenetic processes. Aberrant expression and activation of KATs are commonly observed in human diseases, especially cancer. In recent years, the study of KAT functions in biology and disease has greatly benefited from chemical biology tools and strategies. In this Review, we present the past and current accomplishments in the design of chemical biology approaches for the interrogation of KAT activity and function. These methods and probes are classified according to their mechanisms of action and respective applications, with both strengths and limitations discussed.

Integration of Bioorthogonal Probes and Q-FRET for the Detection of Histone Acetyltransferase Activity

Histone acetyltransferases (HATs) are key players in the epigenetic regulation of gene function. The recent discovery of diverse HAT substrates implies a broad spectrum of cellular functions of HATs. Many pathological processes are also intimately associated with the dysregulation of HAT levels and activities. However, detecting the enzymatic activity of HATs has been challenging, and this has significantly impeded drug discovery. To advance the field, we developed a convenient one-pot, mix-and-read strategy that is capable of directly detecting the acylated histone product through a fluorescent readout. The strategy integrates three technological platforms-bioorthogonal HAT substrate labeling, alkyne-azide click chemistry, and quenching FRET-into one system for effective probing of HAT enzyme activity.

Nanomaterial-based biosensors using dual transducing elements for solution phase detection

Biosensors incorporating nanomaterials have demonstrated superior performance compared to their conventional counterparts. Most reported sensors use nanomaterials as a single transducer of signals, while biosensor designs using dual transducing elements have emerged as new approaches to further improve overall sensing performance. This review focuses on recent developments in nanomaterial-based biosensors using dual transducing elements for solution phase detection. The review begins with a brief introduction of the commonly used nanomaterial transducers suitable for designing dual element sensors, including quantum dots, metal nanoparticles, upconversion nanoparticles, graphene, graphene oxide, carbon nanotubes, and carbon nanodots. This is followed by the presentation of the four basic design principles, namely Förster Resonance Energy Transfer (FRET), Amplified Fluorescence Polarization (AFP), Bio-barcode Assay (BCA) and Chemiluminescence (CL), involving either two kinds of nanomaterials, or one nanomaterial and an organic luminescent agent (e.g. organic dyes, luminescent polymers) as dual transducers. Biomolecular and chemical analytes or biological interactions are detected by their control of the assembly and disassembly of the two transducing elements that change the distance between them, the size of the fluorophore-containing composite, or the catalytic properties of the nanomaterial transducers, among other property changes. Comparative discussions on their respective design rules and overall performances are presented afterwards. Compared with the single transducer biosensor design, such a dual-transducer configuration exhibits much enhanced flexibility and design versatility, allowing biosensors to be more specifically devised for various purposes. The review ends by highlighting some of the further development opportunities in this field.

Stimuli responsive drug delivery application of polymer and silica in biomedicine

In the last decade, using polymer and mesoporous silica materials as efficient drug delivery carriers has attracted great attention.

Polymerization amplified detection for nanoparticle-based biosensing

Efficient signal amplification processes are key to the design of sensitive assays for biomolecule detection. Here, we describe a new assay platform that takes advantage of both polymerization reactions and the aggregation of nanoparticles to amplify signal. In our design, a cascade is set up in which radicals generated by either enzymes or metal ions are polymerized to form polymers that can entangle multiple gold nanoparticles (AuNPs) into aggregates, resulting in a visible color change. Less than 0.05% monomer-to-polymer conversion is required to initiate aggregation, providing high sensitivity toward the radical generating species. Good sensitivity of this assay toward horseradish peroxidase, catalase, and parts per billion concentrations of iron and copper is shown. Incorporation of the oxygen-consuming enzyme glucose oxidase (GOx), enables this assay to be performed in open air conditions at ambient temperature. We anticipate that such a design will provide a useful platform for sensitive detection of a broad range of biomolecules through polymerization-based amplification.

Enzyme-responsive nanoparticles for drug release and diagnostics

Enzymes are key components of the bionanotechnology toolbox that possess exceptional biorecognition capabilities and outstanding catalytic properties. When combined with the unique physical properties of nanomaterials, the resulting enzyme-responsive nanoparticles can be designed to perform functions efficiently and with high specificity for the triggering stimulus. This powerful concept has been successfully applied to the fabrication of drug delivery schemes where the tissue of interest is targeted via release of cargo triggered by the biocatalytic action of an enzyme. Moreover, the chemical transformation of the carrier by the enzyme can also generate therapeutic molecules, therefore paving the way to design multimodal nanomedicines with synergistic effects. Dysregulation of enzymatic activity has been observed in a number of severe pathological conditions, and this observation is useful not only to program drug delivery in vivo but also to fabricate ultrasensitive sensors for diagnosing these diseases. In this review, several enzyme-responsive nanomaterials such as polymer-based nanoparticles, liposomes, gold nanoparticles and quantum dots are introduced, and the modulation of their physicochemical properties by enzymatic activity emphasized. When known, toxicological issues related to the utilization nanomaterials are highlighted. Key examples of enzyme-responsive nanomaterials for drug delivery and diagnostics are presented, classified by the type of effector biomolecule, including hydrolases such as proteases, lipases and glycosidases, and oxidoreductases.