One-pot synthesis of hyaluronic acid–coated gold nanoparticles as SERS substrate for the determination of hyaluronidase activity

A novel ultrasensitive surface-enhanced Raman spectroscopy (SERS)-based method was developed for the determination of hyaluronidase (HAase), which was based on hyaluronic acid–coated gold nanoparticles (HA-AuNPs) as a substrate, via a facile one-pot method. The detection mechanism is based on HAase which can hydrolyze HA on HA-AuNPs into hyaluronic acid oligomers, causing the originally uniformly dispersed HA-AuNPs to be disintegrated into many smaller HA-AuNPs. These oligomers in turn increase the surface shielding of AuNPs, resulting in high aggregation tendencies. As a result, the original SERS substrate was disassembled, leading to a weakening of the SERS signal at 1173 cm⁻¹. Malachite green was also used as a Raman probe to detect the change of SERS peak intensity and to quantify HAase. Compared with other methods for the determination of HAase, this method is more convenient and efficient; its determination limit was 0.4 mU mL⁻¹. The recoveries of HAase spiked into human urine samples ranged from 97.2 to 103.9%.