Highly stable luminescent europium-doped calcium phosphate nanoparticles for creatinine quantification

• Published in: Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2020-12, Vol.196, p.111337-111337, Article 111337
• Main Authors: Ortiz-Gómez, Inmaculada, Ramírez-Rodríguez, Gloria B., Capitán-Vallvey, Luis F., Salinas-Castillo, Alfonso, Delgado-López, José M.
• Format: Article
• Language: English
• Subjects: calcium phosphate; creatinine sensor; europium; luminescent; nanoparticles
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2020.111337

[Display omitted] •Non-toxic, luminescent amorphous calcium phosphate nanoparticles were obtained by europium doping.•The colloidal stability of the nanosensor has been optimized in citrate buffer.•Long-term emission stability: constant signal up to 4 months in storage.•The nanosensor shows high stability, selectivity and sensitivity towards creatinine.•Good recovery percentages were obtained with real urinary samples. The determination of creatinine levels is essential for the detection of renal and muscular dysfunction. Luminescent nanoparticles are emerging as fast, cheap and highly selective sensors for the detection and quantification of creatinine. Nevertheless, current nanosensors only have a short shelf life due to their poor chemical and colloidal stability, which limits their clinical functionality. In this work, we have developed a highly stable, selective and sensitive nanosensor based on europium-doped, amorphous calcium phosphate nanoparticles (Eu-ACP) for the determination of creatinine by luminescence spectroscopy. The colloidal stability of Eu-ACP nanoparticles in aqueous solutions was optimised to ensure a constant signal after up to 4 months in storage. The luminescence intensity of Eu-ACP decreased linearly with the creatinine concentration over the range of 1-120 μM (R2 = 0.995). This concentration–response relationship was used to determine creatinine levels in real urine samples resulting in good recovery percentages. Significantly, selectivity assays indicated that none of the potential interfering species provoked discernible changes in the luminescence intensity.