Surface modification of YAG:Ce³⁺ nanoparticles by poly(acrylic acid) and their biological application

Yttrium aluminum garnet Y₃Al₅O₁₂ (YAG):Ce³⁺ nanoparticles prepared by glycothermal method are modified with poly(acrylic acid) (PAA). This surface modification enables YAG:Ce ³⁺ nanoparticles to be well dispersed in phosphate-buffered saline (PBS) without any serious aggregation. YAG:Ce³⁺ nanoparticles emit yellowish green light under the excitation of blue light. This fluorescent property does not change after the modification of PAA. Streptavidin (SA) is immobilized on the surface of PAA-modified YAG:Ce³⁺ nanoparticles by using carboxyl groups of PAA as cross-linking sites. We demonstrate the quantitative analysis of bovine serum albumin in PBS by SA-immobilized YAG:Ce³⁺ nanoparticles.