Pyrrolidinium octanoate carboxylate as PIL agent in the growth mechanism of lysozyme spherulites

Abstract

International audienceIn this research the impact of pyrrolidinium octanoate carboxylate (PyO) on Lysozyme (Ly) spherulite forms using the method of vapour diffusion with hanging drops (HDVD) was investigated. Two different stock solutions at low alkaline pH were tested: 0.1 M NaAc (the first one) and 0.1 M TRIS hydrochloride contained 0.2 M ammonium sulfate and 25 % wt. PEG 3450 as crystallant agents (the second one). The experiments were performed at 18°C using two PyO concentrations (0.4 M and 1.6 M) in each stock solution. PyO of booth concentrations lead to the formation of Ly - SNLC (Ly single needle-like crystals), observed by optical microscopy one day after the droplets deposition, excepted the stock solution of 0.1 NaAc based on 0.4 M PyO where Ly microspheres were identified by electron scanning microscopy. The growth mechanism of the Ly spherulites of type I obtained using 0.4 M PyO in 0.1 M TRIS/crystallant agent could be summarised as follows: Ly-SNLC → Ly-like axialites → Ly spherulites of type I. The growth mechanism of the Ly spherulites of type II using 1.6 M PyO in 0.1 M TRIS/crystallant agent can be summarised as follows: Ly-SNLC → Ly-like axialites → Ly spherulites of type II