Oligoglycine-functionalized gold nanoparticles: physicochemical characterisation and serum protein interactions

The physicochemical behavior of gold nanoparticles (AuNPs) functionalized with two-antennary oligoglycines is studied by analyzing the colloidal stability and size distribution via dynamic light scattering, the surface-charge reconfiguration through zeta-potential, the nanoscale structure using atomic force microscopy, and the thermodynamic interactions with blood serum using differential scanning calorimetry. These analyses provide an initial assessment of the suitability of the two-antennary oligoglycines as a supramolecular surface-engineering ligand for AuNP-based biomedical applications. The two-antennary oligoglycines form stable complexes with AuNPs, creating a coating layer and reversing surface charge. The interaction between bare nanoparticles and blood serum is weak, primarily affecting albumin. On the other hand, the oligoglycines interact strongly with the blood serum proteins altering their stability. Together, these results demonstrate that two-antennary oligoglycines serve as both a stabilizing and functionalizing layer, thereby enhancing nanoparticle stability and modulating biological interactions. This highlights their potential for the design of well-defined nanomaterials and for applications in drug delivery and other biomedical fields.