Cationic cellulose dispersed Ag NCs/C-CNF paper-based SERS substrate with high homogeneity for creatinine and uric acid detection.

To overcome the problems of easy aggregation, poor reproducibility and homogeneity of metal nanosols, a SERS substrate with good sensitivity, homogeneity and reproducibility was designed and prepared for the detection of disease markers in urine. Silver nanocubes (Ag NCs) were firstly prepared and then dispersed in cationic cellulose (C-CNF) to form a homogeneous gel, which was dropped on a filter paper to develop a substrate with good SERS activity. This substrate combines the superior SERS properties of Ag NCs with the stability of C-CNF and has a minimum detection concentration of 10 M for R6G. The homogeneity of this substrate was good and the RSD value was much <20 %. The SERS substrate was employed for the quantification of creatinine and uric acid, with linear ranges were 5 × 10-5 × 10 M and 10-10 M. The recoveries of creatinine and uric acid were calculated to be 98.3 % ∼ 103.12 % and 96.72 % ∼ 104.48 %, respectively, in the spike recovery experiments, with the relative standard deviations of <10 %. The experimental results show that the method can provide a scientific and reliable experimental basis for screening, condition monitoring and treatment of kidney and other diseases.