Reversible light-controllable intelligent gel based on simple spiropyran-doped with biocompatible lecithin

•A new reversible light-controllable gel-to-sol transition system was constructed.•Spiropyran compound could reversibly coordinate with Ca2+ upon UV/Vis irradiation.•All the gelation components were commercially cheap available.•Spiropyran compound could be prepared by facile material and simple process.

A photochromic spiropyran (SP) compound was doped into a two-component lecithin-Ca2+ organogel, which could coordinate with calcium ions or not by UV/Vis irradiation. Under UV irradiation, SP was isomerized into merocyanine (MC) that coordinated with Ca2+ and resulted in the original pale grey transparent gel transforming to deep-purple fluid, causing the fluid viscosity to decrease nearly 12-fold. Upon exposure to visible light, the MC reverted to the SP form which released the Ca2+ and the organogel was retrieved, also the viscosity recovered its initial value. This cycle could be repeated several times without loss of response. All the gelation components were commercially cheap available and the SP could be prepared by facile material and simple process, so a novel economic and simple organic doped-type light-controllable gel-to-sol transition system was constructed, which provide more possibility for its practical application in controlled drug delivery.

Graphical abstractA novel economic and simple reversible light-controllable gel-to-sol transition system was constructed by doping a photochromic spiropyran compound into a two-component lecithin-Ca2+ organogel, in which SP could reversibly coordinate with Ca2+ upon UV/Vis irradiation. All the gelation components were easily obtained that provided more possibility for its practical application.Figure optionsDownload full-size imageDownload as PowerPoint slide