Signal-amplification and real-time fluorescence anisotropy detection of apyrase by carbon nanoparticle

Nanomaterials Used in Fluorescence Polarization Based Biosensors

Fluorescence polarization (FP) has been applied in detecting chemicals and biomolecules for early-stage diagnosis, food safety analyses, and environmental monitoring. Compared to organic dyes, inorganic nanomaterials such as quantum dots have special fluorescence properties that can enhance the photostability of FP-based biosensing. In addition, nanomaterials, such as metallic nanoparticles, can be used as signal amplifiers to increase fluorescence polarization. In this review paper, different types of nanomaterials used in in FP-based biosensors have been reviewed. The role of each type of nanomaterial, acting as a fluorescent element and/or the signal amplifier, has been discussed. In addition, the advantages of FP-based biosensing systems have been discussed and compared with other fluorescence-based techniques. The integration of nanomaterials and FP techniques allows biosensors to quickly detect analytes in a sensitive and cost-effective manner and positively impact a variety of different fields including early-stage diagnoses.

Recent advances in fluorescence anisotropy/polarization signal amplification

Fluorescence anisotropy/polarization is an attractive and versatile technique based on molecular rotation in biochemical/biophysical systems. Traditional fluorescence anisotropy/polarization assays showed relatively low sensitivity for molecule detection, because widespread molecular masses are too small to produce detectable changes in fluorescence anisotropy/polarization value. In this review, we discuss in detail how the potential of fluorescence anisotropy/polarization signal approach considerably expanded through the implementation of mass amplification, recycle the target amplification, fluorescence probes structure-switching amplification, resonance energy transfer amplification, and provide perspectives at future directions and applications.

Fluorescence Polarization-Based Bioassays: New Horizons

Fluorescence polarization holds considerable promise for bioanalytical systems because it allows the detection of selective interactions in real time and a choice of fluorophores, the detection of which the biosample matrix does not influence; thus, their choice simplifies and accelerates the preparation of samples. For decades, these possibilities were successfully applied in fluorescence polarization immunoassays based on differences in the polarization of fluorophore emissions excited by plane-polarized light, whether in a free state or as part of an immune complex. However, the results of recent studies demonstrate the efficacy of fluorescence polarization as a detected signal in many bioanalytical methods. This review summarizes and comparatively characterizes these developments. It considers the integration of fluorescence polarization with the use of alternative receptor molecules and various fluorophores; different schemes for the formation of detectable complexes and the amplification of the signals generated by them. New techniques for the detection of metal ions, nucleic acids, and enzymatic reactions based on fluorescence polarization are also considered.

Magnetic nanoparticles and polydopamine amplified FP aptasensor for the highly sensitive detection of rHuEPO-α

In this paper, an amplified fluorescence polarization (FP) aptasensor based on magnetic nanoparticles @polydopamine (MNP@PDA) was innovatively developed for sensitive detection of recombinant human erythropoietin-alpha(rHuEPO-α). The amplified FP signal was due to the large mass of protein and MNP@PDA. And this assay can be utilized for target separation or recycling based on the magnetic property of MNP@PDA through magnetic separation. Briefly, rHuEPO-α and MNP@PDA were added successively to react with the labeled aptamer (FAM-P1), which both contributed to the increase of FP signal via the formation of FAM-P1-rHuEPO-α and particularly FAM-P1-MNP@PDA complex. The strong interaction between MNP@PDA and FAM-P1 ensured the high efficiency of mass amplification and magnetic separation. As a result, the detection limit for rHuEPO-α was 0.12 pM, 4 orders of magnitude lower than original assay. Besides, three kinds of rHuEPO-α injections, NuPIAO, Epogen and ESPO were used to evaluate the selectivity of this assay in complex matrix with reasonable standard deviation. In a word, this work provides a simple, rapid, non-modified, highly sensitive and selective sensing platform for the detection of rHuEPO-α.

Panoply of Fluorescence Polarization/Anisotropy Signaling Mechanisms for Functional Nucleic Acid-Based Sensing Platforms

Fluorescence polarization/anisotropy is a very popular technique that is widely used in homogeneous-phase immunoassays for the small molecule quantification. In the present Feature, we discuss how the potential of this signaling approach considerably expanded during the last 2 decades through the implementation of a myriad of original transducing strategies that use functional nucleic acid recognition elements as a promising alternative to antibodies.

An electricity-fluorescence double-checking biosensor based on graphene for detection of binding kinetics of DNA hybridization

In this paper, an electricity-fluorescence double-checking biosensor based on graphene materials has been presented for detection of DNA hybridization kinetics.

Graphene oxide amplified fluorescence anisotropy for label-free detection of potassium ion

A label-free fluorescence anisotropy method for the sensitive detection of potassium ion, by using graphene oxide as enhancer, was established.

A novel graphene oxide amplified fluorescence anisotropy assay with improved accuracy and sensitivity

A novel and versatile graphene oxide (GO) amplified fluorescence anisotropy (FA) strategy with improved accuracy and sensitivity has been successfully developed.