PEGylated Gold Nanoparticles as Novel Agglutination Enhancement Medium for Antibody Screening Test

To develop a novel enhancement medium using polyethylene glycol (PEG)-conjugated gold nanoparticles (AuNPs) for improved detection of clinically significant alloantibodies in antibody screening tests (AST), addressing the limitations of low ionic strength solution (LISS). PEG AuNPs were synthesized through a one-step method and characterized using UV-Visible spectroscopy, EFTEM, FESEM, particle size analysis, zeta potential measurement, and FT-IR spectroscopy. The PEG AuNPs' performance was evaluated against LISS in 120 plasma samples (both antibody-positive and negative) by scoring RBC agglutination reactions. Synthesized PEG AuNPs showed a ruby red color with a single absorption peak at 529 nm, confirming AuNP surface plasmon resonance. Spherical colloids averaged 152.73 ± 19.59 nm, with stability indicated by a zeta potential of -6.24 ± 0.57 mV. Significantly higher RBC agglutination scores were observed with PEG AuNPs during the anti-human globulin (AHG) phase (p = 0.010), especially for anti-D and anti-Le^a/anti-Le^b antibodies (p = 0.007 and 0.036, respectively). PEGylated AuNPs significantly enhanced RBC agglutination reactions compared to LISS, particularly for anti-D and combined anti-Le^a/anti-Le^b antibodies, presenting a promising alternative for AST.