A Label-free, Highly Sensitive and Selective Detection of Hemin Based on the Competition between Hemin and Protoporphyrin IX Binding to G-Quadruplexes

Abstract

Herein is reported a simple and label-free fluorescent detection method for hemin based on using protoporphyrin IX (PPIX) as a fluorescent signal reporter. PPIX emits weak fluorescence in an aqueous solution. When PPIX binds to G-quadruplexes, the fluorescence intensity of PPIX is greatly increased. While in the presence of target hemin, hemin competes with PPIX toward G-quadruplexes because its affinity to G-quadruplexes is higher than that of PPIX. With the formation of the hemin-G-quadruplex complex, PPIX is released to the solution from the G-quadruplex accompanied by quenching of the fluorescence of the system. This fluorescence change of the system can be used to monitor hemin with a low detection limit of 36 nM. In addition, the possible binding sites for PPIX binding to the G-quadruplex are discussed based on competition between hemin and PPIX. What is more, this method might pave the way for applying G-quadruplexes and PPIX to more sensing systems.

Acid‐treated Graphitic Carbon Nitride Nanosheets as Fluorescence Probe for Detection of Hemin

“…At present, various methods for detecting hemin have been found, for example, fluorometry, voltammetric determination, chemiluminescence, 12 spectrophotometric and electrochemistry . Compared to these methods, fluorometric (FL) analysis was widely investigated due to its high sensitivity, highly selectivity and simple operation .…”

A DNA Switch for Detecting Single Nucleotide Polymorphism within a Long DNA Sequence Under Denaturing Conditions

“…This activity is known as peroxidase activity, and therefore, these types of DNA molecules are also called peroxidase DNAzymes . They can also bind to certain fluorogenic molecules, such as protoporphyrin IX (PPIX), to produce a strong fluorescence signal (Figure C) . Therefore, ULX can function as an excellent colorimetric or fluorescent signaling module to build a biosensing system to achieve target detection in 7MU.…”

“…[24][25][26] They can also bind to certain fluorogenic molecules, such as protoporphyrin IX (PPIX), to produce as trong fluorescence signal ( Figure 1C). [27][28][29] Therefore, ULX can function as an excellent colorimetric or fluorescent signaling module to build a biosensing system to achieve target detection in 7MU.…”

A Thioflavin T-induced G-Quadruplex Fluorescent Biosensor for Target DNA Detection

“…25,26 Among these dyes for G-quadruplex, thioflavin T (ThT) has increasingly attracted the attention of researchers to become a new focus in the construction of G-quadruplex fluorescent biosensors, mainly due to its satisfactory water solubility and low cost. 27 Compared to conventional dyes, such as N-methylmesoporphyrin IX (NMM) 28 and protoporphyrin IX (PPIX), 29 the system adopting ThT as a fluorescent probe for G-quadruplex avoids using an organic solvent to dissolve the dye. Herein, we tactfully designed a simple biosensor for a target DNA assay by using ThT as a fluorescent probe for G-quadruplex.…”