Cystatin C for chronic kidney disease monitoring via the application of gold core-shells in lateral flow immunoassays

The lateral flow (LF) immunoassays in biosensing are universally applied for point-of-care disease monitoring purposes with gold nanoparticles (AuNPs). With a highlight on nanomaterial gold core-shells (AuCSs), here we characterise the conjugation of monoclonal antibodies (mAbs) with AuCSs in Cystatin C (CysC) diagnostics via scanning electron microscopy (SEM), dynamic light scattering (DLS), and ultraviolet-visible (UV-Vis) spectroscopy. Two formats AuCSs used in the conjugation include the lyophilised powder format (NHS-dried) and carboxyl surfaced particles in liquid form. The AuCSs performance was demonstrated by extracting the grey intensity of the LF test line (T) and control line (C) for respective areas under the curve calculation and T/C ratio (Test line intensity / Control line intensity). The translucent coloured AuCSs (NHS-dried) peak at 801 nm in UV-Vis with conjugated mAbs concentration at 357.8 ?g/ml, the conjugated AuCSs hydrodynamic size maximize at 234.9 9.7 nm, with 100 ?g/ml mAbs. Similarly, the carboxyl surfaced AuCSs obtain the UV-Vis maximum absorption at 840 nm wavelength with mAbs concentration at 358 ?g/ml. Correspondently, the conjugated AuCSs hydrodynamic size peaks at 240.4 3.8 nm with mAbs concentration at 1253 ?g/ml. For qualitative LF, AuNPs and AuCSs propose the equivalent capability in foretelling the existence of CysC. For quantitative purposes, AuCSs with fainter test lines would enable a wider CysC detection range.