Detection of Biomarkers Associated with Acute Kidney Injury by a Gold Nanoparticle Based Colloidal Nano-Immunosensor by Fourier-Transform Infrared Spectroscopy with Principal Component Analysis

A colloidal nano-immunosensor based on gold nanoparticles covered in their surface with protein A and the immunoglobulin anti-kidney injury molecule-1 was prepared and tested in human urine to identify a biomarker that diagnose acute kidney injury. The urine was obtained from patients with cancer treated with cisplatin, diagnosed with acute kidney injury, and from healthy individuals. Fourier-transform infrared spectroscopy analysis showed important spectral differences between both types of groups, primarily for the intervals from 1750 to 1500 cm⁻¹ and from 1000 to 891 cm⁻¹ where the amide I group (C = O) and the glycosylated functional groups of this protein absorb. The principal component analysis applied to the vibrational signals obtained with the nano-immunosensor allows adequate discrimination of urine from patients with acute kidney injury from samples from healthy individuals. The simplicity of the proposed method, from the preparation of the nano-immunosensor to the spectral and chemometric analysis, may make this method an interesting alternative to practically diagnose acute kidney injury using a small volume of urine.