Ratiometric Fluorescence Detection Of Biomolecules Based On Energy Transfer Of Nucleotide-Lanthanide Coordination Polymers

Lanthanide coordination polymers are widely used in antibacterial,bioimaging,logic gate construction and biosensing because of their unique optical,magnetic and electrical properties.In particular,it has unique luminescent properties,high chromaticity,narrow emission band,large stokes shift and long fluorescence lifetime?millisecond?.These properties make it a very large application potential in the field of biosensing.In this paper,several composite nanoparticles were designed,and the ratiometric detection biomolecules were realized by changing the internal energy transfer process.Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid?DPA?.However,mainly based on DPA sensitization to the lanthanide core,most of them failed to realize robust detection of DPA in bacterial spores.We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions,Tb³⁺and Eu³⁺,and guanosine 5`-monophosphate.This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA,enabling accurate detection of DPA in complex biosystems such as bacterial spores.DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging.This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.Similar to the above design protocol,we synthesized a heterobinuclear rlanthanide coordination polymer,AMP-Tb/Ce,by self-assembly of adenosine monophosphate?AMP?and Ce³⁺,Tb³⁺,AMP-Tb/Ce shows very good luminescent based on the internal energy transfer process of nanoparticles?AMP?Ce?Tb?.Lanthanide coordination polymers have very good self-assembly properties and can encapsulate various guest molecules.Therefore,we encapsulate the two guest molecules rhodamine B?RhB?and glucose oxidase?GOx?into AMP-Tb/Ce using their encapsulation properties.The composite nanomaterial RhB&GOx@AMP-Tb/Ce was successfully constructed.The guest molecule GOx has catalytic ability,and there is an energy transfer process between RhB and Tb³⁺.Based on the tandem energy transfer process in the above composite nanomaterial,it provides a basis for us to design a proportional sensing platform.Therefore,we will design the composite nanomaterial for glucose sensing.Glucose can be oxidized to produce gluconic acid and hydrogen peroxide in the presence of GOx.Ce³⁺in the AMP-Tb/Ce structure can be oxidized by hydrogen peroxide to Ce⁴⁺,resulting in that its internal tandem energy transfer process is interrupted,which in turn achieves the ratiometric fluorescence response of RhB&GOx@AMP-Tb/Ce to glucose.It has excellent sensitivity,high selectivity and anti-interference ability,and has a very good advantage in the detection of actual samples.GMP and Gd³⁺can form a coordination polymer GMP-Gd by coordination self-assembly.The guest molecule can be encapsulated by introducing it in the self-assembly process.In this work,two noble metal nanoclusters were encapsulated into GMP-Gd to prepare AgNCs&AuNCs@GMP-Gd.When GSH-AgNCs and Met-AuNCs were encapsulated by GMP-Gd,energy transfer process occurred from GSH-AgNCs to Met-AuNCs.AgNCs&AuNCs@GMP-Gd shows the luminescence of Met-AuNCs.The introduction of alkaline phosphatase?ALP?cleaved the phosphate group from GMP,which weakens the coordination ability of GMP and Gd³⁺and destroys the structure of GMP-Gd.GSH-AgNCs and Met-AuNCs released from GMP-Gd.Since both nanoclusters are negatively charged,the two are mutually exclusive and no efficient energy transfer can occur.The luminescence of Met-AuNCs?585 nm?is decreased,while the luminescence of GSH-AgNCs?455 nm?is enhanced.Therefore,a ratiometric fluorescence sensing platform for ALP was constructed.I_455nm/I_585nm shows a linear relationship with the concentration of ALP in the range of 0.18-0.48 U·mL^-1.The detection limit is down to 0.051 U·mL^-1.The sensing platform can also be used to evaluate the performance of ALP inhibitors.A simple and sensitive method for ALP activity assays is provided.