ABSTRACT
A novel aggregation-induced emission (AIE) probe comprised of a hydrophilic protein kinase specific peptide and a hydrophobic tetraphenylethene (TPE) unit was synthesized through click reaction. The prepared TPE-peptide probe could be completely degraded by carboxypeptidase Y (CPY) to release hydrophobic TPE part, which aggregated in buffer solution and showed strong TPE emission. In the presence of casein kinase (CKII), the phosphorylation of peptide prevented the complete degradation by CPY producing the nonemissive probe. Thus, the developed probe can be used to detect CKII homogeneously and conveniently. This detection process can be finished within 1.5â¯h with high sensitivity (0.05 mU/µL) and good selectivity. The developed method can also be used to screen protein kinase inhibitor even in a complex biological system.
Subject(s)
Biosensing Techniques/methods , Casein Kinase II/analysis , Enzyme Assays/methods , Spectrometry, Fluorescence/methods , Benzylidene Compounds/chemical synthesis , Benzylidene Compounds/chemistry , Casein Kinase II/chemistry , Cathepsin A/chemistry , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Oligopeptides/chemical synthesis , Oligopeptides/chemistry , Phosphorylation , Protein Kinase Inhibitors/chemistry , Proteolysis , Triazoles/chemistryABSTRACT
Novel cathodic photoelectrochemical (PEC) aptasensors for sensitive and selective determination of thrombin and Pb2+ were developed based on a new dual-signal amplification strategy. The presence of gold nanoparticles (AuNPs) could quench the PEC signal of bismuth oxyiodide (BiOI). At the same time, the redox moiety G-quadruplex/hemin or ferrocene (Fc) was found to enhance the PEC signal of BiOI. So, in the presence of thrombin or Pb2+, the interaction between target and the aptamer resulted in the releasement of the AuNPs, as well as shorter distance between the redox moiety and the electrode surface. Hence dual-enhanced cathodic PEC biosensor strategy was realized. Under the optimized conditions, the detection limits of thrombin and Pb2+ were 17.3â¯fM and 3.16â¯pM, respectively with good selectivity. At the same time, the PEC performance of redox moiety G-quadruplex/hemin and Fc was compared.
Subject(s)
Biosensing Techniques/methods , Electrochemical Techniques/methods , Lead/analysis , Thrombin/analysis , Electrodes , Ferrous Compounds/chemistry , Gold/chemistry , Hemin/chemistry , Metal Nanoparticles/chemistry , Metallocenes/chemistry , PhotochemistryABSTRACT
A novel detection method based on the cation-exchange reaction of CuS nanoparticles (CuS NPs) combined with poly T-templated fluorescent Cu nanoparticles (Cu NPs) was developed. First, CuS NPs-magnetic bead conjugates were prepared through the hybridization of DNA. Competition with target DNA resulted in the release of CuS NPs, and exonuclease III catalysis could lead to recycling of the target DNA. Then, the CuS NPs released into the supernatant were subjected to a cation-exchange reaction after the addition of AgNO3. The obtained Cu2+ could form fluorescent Cu NPs using poly T DNA as a template. The fluorescence intensity of the Cu NPs could be used to determine the concentration of the target DNA. To further increase the detection sensitivity, two types of DNA decorated magnetic beads were used. After Exo III digestion for two cycle processes, more CuS NPs entered the supernatant. Hence, a stronger fluorescence intensity was found after the cation-exchange reaction and the formation of fluorescent Cu NPs. The developed method is convenient and low cost with good sensitivity and selectivity.
