Resonance elastic light scattering (RELS) spectroscopy of fast non-Langmuirian ligand-exchange in glutathione-induced gold nanoparticle assembly

Detection of Oxidative Stress Biomarkers Using Novel Nanostructured Biosensors

“…replacing short-chain citrate molecules in the nanoparticle shell with longer-chain GSH molecules) and interparticle interactions leading to AuNP assembly. In contrast to the behavior of NT, Hcys and GSH, replace nonthiolated AuNP shell and in the proper pH range induce assembly of gold nanoparticles ( Figure 5) (Lim et al, 2007, Lim et al, 2008, Stobiecka et al, 2010a, Stobiecka et al, 2010b. Large increase of the RELS signal was reported for both GSH and Hcys confirming the assembly process (Stobiecka et al, 2010a, Stobiecka et al, 2010b.…”

“…From the data of Figure 4a, the scattering intensity increase is: I sc,1 /I sc,0 = 1.695 and, hence, a rel = 1.192. This increase in a rel is relatively small and indicates that aggregates of AuNP are not formed, otherwise the value of a rel ≥ 2 should be obtained (Stobiecka et al, 2010a, Stobiecka et al, 2010b. Therefore, the increase in particle diameter observed upon interactions of AuNP with NT is due to the attachment of NT to the outer interface of the AET-capped AuNP shell.…”

“…In contrast to the behavior of NT, Hcys and GSH, replace nonthiolated AuNP shell and in the proper pH range induce assembly of gold nanoparticles ( Figure 5) (Lim et al, 2007, Lim et al, 2008, Stobiecka et al, 2010a, Stobiecka et al, 2010b. Large increase of the RELS signal was reported for both GSH and Hcys confirming the assembly process (Stobiecka et al, 2010a, Stobiecka et al, 2010b. While in the Hcys-induced assembly, the main forces are Hbonding, in the case of GSH-induced assembly, the zwitterionic forces are dominant, although the H-bonding plays also a role (Lim et al, 2007, Lim et al, 2008.…”

“…The affinity of thiols to a Au surface (Whitesides et al, 2005) enables such thiols as GSH and homocysteine to readily replace citrates from the nanoparticle shell (Lim et al, 2007, Lim et al, 2008, Stobiecka et al, 2010b. While GSH can form intermittently some weakly bound intermediate interparticle linking structures (Stobiecka et al, 2010a), these only help to isolate a citrate ion from its neighbors and remove that citrate from the film.…”

“…The analysis of biomarkers of oxidative stress, such as glutathione (GSH), glutathione disulfide (GSSG), 3-nitrotyrosine, homocysteine, nonenal, etc., becomes the key factor for preventive treatments (Knoll et al, 2005, Kohen et al, 2002, Malinski et al, 1992, Reddy et al, 2004, Stobiecka et al, 2009, Stobiecka et al, 2010a. Since the main redox potential maintaining system in eukaryotic cell homeostasis is the GSH/GSSG redox couple (Noble et al, 2005), we have focused on the design of GSH immunosensor.…”