DNA-Encoded Signal Conversion for Sensitive Microgravimetric Detection of Small Molecule–Protein Interaction

Electrochemical detection of protein by using magnetic graphene-based target enrichment and copper nanoparticles-assisted signal amplification

A new electrochemical method for protein detection has been proposed based on magnetic graphene and duplex DNA-templated copper nanoparticles.

Quartz crystal microbalance detection of protein amplified by nicked circling, rolling circle amplification and biocatalytic precipitation

A novel quartz crystal microbalance (QCM) assay was described for sensitive detection of protein. Lysozyme was used as a model of protein. To enhance the sensitivity of this QCM biosensor, biocatalytic precipitation (BCP) reaction combined with strand-scission cycle and rolling circle amplification (RCA) were applied together for the first time. As a result of the multi-signal amplification in this aptasensor, the detection limit for lysozyme was down to 0.3fM. What is more, this amplified QCM biosensor also showed good selectivity and practical usage in human serum.

The heat-transfer method: a versatile low-cost, label-free, fast, and user-friendly readout platform for biosensor applications

In recent years, biosensors have become increasingly important in various scientific domains including medicine, biology, and pharmacology, resulting in an increased demand for fast and effective readout techniques. In this Spotlight on Applications, we report on the recently developed heat-transfer method (HTM) and illustrate the use of the technique by zooming in on four established bio(mimetic) sensor applications: (i) mutation analysis in DNA sequences, (ii) cancer cell identification through surface-imprinted polymers, (iii) detection of neurotransmitters with molecularly imprinted polymers, and (iv) phase-transition analysis in lipid vesicle layers. The methodology is based on changes in heat-transfer resistance at a functionalized solid-liquid interface. To this extent, the device applies a temperature gradient over this interface and monitors the temperature underneath and above the functionalized chip in time. The heat-transfer resistance can be obtained by dividing this temperature gradient by the power needed to achieve a programmed temperature. The low-cost, fast, label-free and user-friendly nature of the technology in combination with a high degree of specificity, selectivity, and sensitivity makes HTM a promising sensor technology.

Terminal protection of small molecule-linked DNA for small molecule-protein interaction assays

Methods for the detection of specific interactions between diverse proteins and various small-molecule ligands are of significant importance in understanding the mechanisms of many critical physiological processes of organisms. The techniques also represent a major avenue to drug screening, molecular diagnostics, and public safety monitoring. Terminal protection assay of small molecule-linked DNA is a demonstrated novel methodology which has exhibited great potential for the development of simple, sensitive, specific and high-throughput methods for the detection of small molecule–protein interactions. Herein, we review the basic principle of terminal protection assay, the development of associated methods, and the signal amplification strategies adopted for performance improving in small molecule–protein interaction assay.

An electronic channel switching-based aptasensor for ultrasensitive protein detection

Due to the ubiquity and essential of the proteins in all living organisms, the identification and quantification of disease-specific proteins are particularly important. Because the conformational change of aptamer upon its target or probe/target/probe sandwich often is the primary prerequisite for the design of an electrochemical aptameric assay system, it is extremely difficult to construct the electrochemical aptasensor for protein assay because the corresponding aptamers cannot often meet the requirement. To circumvent the obstacles mentioned, an electronic channel switching-based (ECS) aptasensor for ultrasensitive protein detection is developed. The essential achievement made is that an innovative sensing concept is proposed: the hairpin structure of aptamer is designed to pull electroactive species toward electrode surface and makes the surface-immobilized IgE serve as a barrier that separates enzyme from its substrate. It seemingly ensures that the ECS aptasensor exhibits most excellent assay features, such as, a detection limit of 4.44×10(-6)μg mL(-1) (22.7fM, 220zmol in 10-μL sample) (demonstrating a 5 orders of magnitude improvement in detection sensitivity compared with classical electronic aptasensors) and dynamic response range from 4.44×10(-6) to 4.44×10(-1)μg mL(-1). We believe that the described sensing concept here might open a new avenue for the detection of proteins and other biomacromolecules.