Ultrasensitive detection of amifostine and alkaline phosphatase based on the growth of CdS quantum dots

Silver nanoparticles conjugated MnFe-based Prussian blue analogue for voltammetric and impedimetric bioaptasensing of amifostine (ethyol)

A novel bioaptasensing-based electrochemical method for determination of amifostine (AMF) is proposed. The electrochemical aptasensor is based on modification of a glassy carbon electrode with a nanocomposite consisting of silver nanoparticles @ MnFe Prussian blue analogue nanospheres (AgNPs@MnFePBA NS), followed by immobilization of aptamer via Ag-N bonds (aptamer/AgNPs@MnFePBA NS/GCE). Experimental parameters including pH, incubation time, and aptamer concentrations were optimized. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetric (DPV) techniques were utilized to quantify AMF. The anodic peak current (∆Ipa) and charge transfer resistance (∆Rct) differences increase in the presence of AMF. Under the optimal conditions, using the redox probe, the electrochemical aptasensor exhibited linear ranges of 0.34-45 nmol L^-1 and 0.69-45 nmol L^-1 with LODs of 0.11 nmol L^-1 and 0.23 nmol L^-1 for EIS and DPV, respectively. The aptasensor was used to determine AMF in human plasma and in the presence of interfering species with recoveries and RSDs in the range 97.8-103.2% and 2.2-4.2%, respectively. Graphical abstract.

A review on emerging principles and strategies for colorimetric and fluorescent detection of alkaline phosphatase activity

Alkaline phosphatase (ALP) is a natural enzyme that is able to catalyze the dephosphorylation of phosphate esters. It participates in a great number of biological processes ranging from various metabolisms to signal transduction and cellular regulation. Since the abnormality of ALP activity in body is closely associated with many diseases, it has become an important biomarker for clinical diagnosis and treatment. Besides, it is often utilized in enzyme-linked immunosorbent assays. Given these demands, in the last few years considerable interest has been focused on exploring new materials and methods for ALP activity detection. In this review, we first made a clear classification on the principles that could be used for ALP activity determination. After that, emerging colorimetric and fluorescent strategies designed on the basis of these principles were systematically summarized. Finally, some perspectives on ALP activity analysis were discussed, hoping to inspire future efforts in the field.

Extracellular biosynthesis of biocompatible cadmium sulfide quantum dots using Trametes versicolor

Quantum dots are important fluorescent semiconductor nano-crystals with distinguished electrical and optical properties and have gained great interest in many fields. The chemical and physical synthetic methods are usually not favorable for biological application due to high energy-consumption procedure and residual toxic chemicals. The development of novel "green" routes to prepare bio-compatible cadmium sulfide quantum dots constitutes a promising substituted approach. We used the white rot fungus Trametes versicolor for the biosynthesis of cadmium sulfide quantum dots taking account of the adsorption property of this fungus. Multiple physical characterizations involving scanning electron microscope (SEM), ultraviolet-visible (UV-vis) and photoluminescence (PL) spectroscopy, fourier transform infrared spectroscopy (FTIR), thermo-gravimetric (TG), transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed surface, optical and thermal characteristics, crystalline nature, size and shape distributions of the nanoparticles. This study provided a suitable and efficient approach to synthesize stable biocompatible cadmium sulfide quantum dots using the fungus Trametes versicolor with great potentials in the biological and biomedical researches.

Dual mode detection of amifostine based on gold nanoparticles and sulfanilic acid functionalized graphene quantum dots

Visual and fluorescence detection of amifostine based on the inner filter effect of gold nanoparticles on sulfanilic acid functionalized graphene quantum dots.