Novel gluconate stabilized gold nanoparticles as a colorimetric sensor for quantitative evaluation of spermine

Abstract

In the fields of biology and pharmacy, water dispersible gold nanoparticles (AuNPs) with bio-friendly capping agents are always in demand. Gluconate is a substance that is compatible with biological systems. Gluconate stabilized AuNPs (abbrv.: Glu-AuNPs) were synthesized in water and characterized utilizing UV-Vis spectroscopy, DLS, TEM, and Raman spectroscopy tools, as well as a DFT computing investigation. The Glu-AuNPs are extremely stable in the pH range of 4–10 and exhibit SPR band maximum at 518 nm. According to TEM and DLS investigation, the particle sizes are 7.03 ± 2 nm and 14 nm, respectively. They have an FCC crystalline structure. The Raman and DFT computation studies reveal that the gluconate ions adsorbed onto the surface of AuNPs and provided much needed stability of the particles against agglomeration. The computed binding energy of Glu-O(COO) to Au3 cluster is − 5.22 eV, which is quite high. The particles have been ascertained as colorimetric and UV-Vis spectrophotometric nanosensor for spermine (SM), a biomarker for cancer diagnosis. The SM was quantified by monitoring changes in the feature of the SPR band maximum of Glu-AuNPs as a result of its aggregation. The LoD value is 0.2511 μM. As evidenced by the computed Kasso value of 2.183 × 106 M−1, the SM---AuNPs interactions are quite strong. The nanosensor exhibits excellent recovery results against real samples.