GdPO₄-Based Nanoprobe for Bioimaging and Selective Recognition of Dipicolinic Acid and Cysteine by a Sensing Ensemble Approach

Abstract

Multiple functions incorporated in one single-component nanoplatform pave the way for important biomedicine applications. Herein, a multifunctional terbium-doped gadolinium orthophosphate (GdPO4:Tb-EDTA) nanoplatform was prepared through a simple, ecofriendly, one-step hydrothermal method. Results showed that dipicolinic acid (DPA), the biomarker of bacterial spores, significantly increased the fluorescence intensity of this nanoplatform and conferred it with rapid response and excellent selectivity. Subsequently, the fluorescence of the ensemble GdPO4:Tb-EDTA-DPA can be remarkably quenched by Cu2+, which led to a rewritable nanosensor used in the detection of cysteine (Cys) with excellent sensitivity. In addition, GdPO4:Tb-EDTA can also be a potential T 1-weighted magnetic resonance imaging (MRI) contrast agent, which indicated a satisfactory in vitro MRI with r 1 relaxivity values of 13.9 mM–1 s–1 and in vivo MRI through intravenous administration on a rat model. Overall, the proposed assay may have great theoretical and practical significance for designing multifunctional biomaterials.

Effect of Cationic Brush-Type Copolymers on the Colloidal Stability of GdPO4 Particles with Different Morphologies in Biological Aqueous Media

“…Gadolinium-based particles can potentially be applied as MRI contrast agents because the Gd 3+ ion has seven unpaired electrons in its 4f orbital. 21 − 23 There is plenty of published research regarding the synthesis and investigation of Gd-based nanoparticles such as GdPO 4 , GdF 3 , NaGdF 4 , and Gd 2 O 3 . Gd-based nanoparticles are suitable hosts for doping with lanthanide ions in order to enrich these materials with additional luminescence properties.…”

“…Gd-based nanoparticles are suitable hosts for doping with lanthanide ions in order to enrich these materials with additional luminescence properties. 5 , 19 , 20 , 23 − 25 One the most widely studied Gd-based particles is NaGdF 4 doped with various lanthanide ions. Such particles are often referred to as potential biomarkers in biomedicine.…”

“…For this reason, various low-molecular-weight surfactants such as TWEEN, CTAB, and TRITON are used to enhance the stability of various nanoparticle systems. 23 , 39 , 52 − 55 Even though the use of various commercial surfactants often prevents particles from agglomerating, such surface modification cannot always ensure the desired stability of nanoparticles, especially in water. There is currently no effective universal way to ensure the colloidal stability of various nano- and microsized particles in aqueous colloids.…”

“…Rare-earth-doped nanoparticles are materials of great interest lately. , The type of nanoparticle which can be excluded from the others would be those containing Gd 3+ ions in their composition. Gadolinium-based particles can potentially be applied as MRI contrast agents because the Gd 3+ ion has seven unpaired electrons in its 4f orbital. − There is plenty of published research regarding the synthesis and investigation of Gd-based nanoparticles such as GdPO 4 , GdF 3 , NaGdF 4 , and Gd 2 O 3 . Gd-based nanoparticles are suitable hosts for doping with lanthanide ions in order to enrich these materials with additional luminescence properties. ,,,− One the most widely studied Gd-based particles is NaGdF 4 doped with various lanthanide ions.…”

“…Gadolinium-based particles can potentially be applied as MRI contrast agents because the Gd 3+ ion has seven unpaired electrons in its 4f orbital. − There is plenty of published research regarding the synthesis and investigation of Gd-based nanoparticles such as GdPO 4 , GdF 3 , NaGdF 4 , and Gd 2 O 3 . Gd-based nanoparticles are suitable hosts for doping with lanthanide ions in order to enrich these materials with additional luminescence properties. ,,,− One the most widely studied Gd-based particles is NaGdF 4 doped with various lanthanide ions. Such particles are often referred to as potential biomarkers in biomedicine. − However, the commonly used thermal decomposition synthesis method leads to hydrophobic nanoparticles due to employed oleic acid, which remains on the particle surface. − A hydrophobic surface prevents any colloidal stability of NaGdF 4 particles in aqueous media; therefore, a change in surface ligands or additional surface modification is needed in order to achieve the colloidal stability of such particles in aqueous media …”