In a plethora of biological assay, biomolecules (including DNA, proteins and peptides) are immobilized on AuNPs to provide labeling of analytes within the assay. The choice of the optimal modification strategy strongly influences the overall performance of the entire assay itself in terms of specificity, sensitivity and nonspecific binding (thus impacting on the signal-to-noise ratio and limit of detection). In this work, 80 nm SiGNPs were coated with copoly azide 4%. The polymer contains azide groups that are capable of reacting with DBCO-modified biomolecules. Conjugation occurred through incubating the polymer coated SiGNPs with the biomolecule solution under appropriate conditions (pH, temperature, buffer), resulting in biomolecules binding to azide groups on the SiGNP surface via covalent bonding.