Cyclic voltammetric deposition of PPI and AuNP on the GCE, theref

Cyclic voltammetric deposition of PPI and AuNP on the GCE, therefore, involves the formation of amine linkages between PPI and GCE while the AuNP were simultaneously deposited with the PPI.Figure 2.Structure of G4 Poly(propylene imine) dendrimer showing the peripheral primary amine and internal tertiary amine.Figure 3a, compares the electrochemical behaviour of GCE/PPI-AuNP (dotted line) against the bare GCE (solid line) in PBS. The PPI-AuNP composite film exhibited reversible electrochemistry characteristic of surface adsorbed species with formal potential E0�� = 233 �� 5 mV for six different measurements demonstrating the good reproducibility of the composite platform. To ascertain the species responsible for the reversible peaks, PPI and AuNP were deposited alone (Figures 3b and and3c).3c). In Figure 3b, ,33 mM PPI in PBS solution exhibited a quasi-reversible electrochemistry and when it was electro-deposited, the anodic and cathodic peaks separation became less. In Figure 3c, where only AuNP was deposited on GCE, no peaks were observed. This meant that the pair of peaks observed in Figure 3a (dotted line) was due to the PPI component of the nanocomposite. The reversibility of the electrochemical oxidation/reduction occurring within the PPI-AuNP nanocomposite platform was selleck chemicals confirmed by the ratio of anodic (Ipa) to cathodic (Ipc) peak currents, which was calculated to give 0.992. Also the anodic and cathodic square wave voltammograms gave approximately the same peak potential value (see Figure 3d). In addition, the integration of the anodic and cathodic CV peaks from Figure 3a (wave GCE/PPI-AuNP) gave charges of 528.1 nC and -524.7 nC, respectively, which are the same within experimental error.Figure 3.(a) CV of GCE and GCE/PPI-AuNP in PBS from -100 mV to 650 mV at 20 mV/s. (b) CV of 3 mM PPI solution on GCE and GCE/PPI. Background electrolyte is 10 mM PBS. (c) CV of GCE and GCE/AuNP with ssDNA and dsDNA in PBS. (d) Oxidative and reductive square wave …Figure 4a shows the CV of GCE/PPI-AuNP at different scan rate in PBS. From this figure, (i) the currents increased with increase in scan rate with no shift in potential, (ii) Ipa was proportional to scan rate and (iii) a plot of Ipa versus scan rate showed linearity (Figure 4a inset) with a correlation coefficient of 0.9978. It can thus be deduced that the platform was conducting and exhibited a reversible electrochemistry characteristic of surface adsorbed specie because Ipa versus scan rate was linear. Ideally, for surface adsorbed specie, Epa should be the same as Epc. However,
Ligand-receptor interaction in biological membranes plays important roles in the initiation of signal transduction [1]. For instance, signal transduction in nerve systems is mediated by neurotransmitters that bind to the receptor at postsynaptic membranes.

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