Modulation of phospholipid membranes by curcumin-conjugated silver nanoparticles and their application -

Abstract

Nanotechnology is a field of science involving the synthesis and development of nanomaterials. Silver nanoparticles (AgNPs) have been incorporated in several biomedical and environmental applications because of their chemical stability, catalytic activity, and enhanced conductivity. Green synthetic routes have been an emerging field to synthesize AgNPs. These routes help minimize the use of hazardous substances therefore reducing the formation of toxic products. Curcumin can be used as a reducing agent in the green synthesis of AgNPs. Curcumin is the active ingredient of turmeric, a medicinal and dietary spice extracted from Curcuma longa. Although extensive research has proven curcumin as a potential drug for various diseases such as Alzheimer’s disease, carcinogenesis, and inflammatory disorders, curcumin’s poor bioavailability limits its therapeutic efficacy. Therefore, numerous approaches have been developed to enhance curcumin’s therapeutic utility. These include co-administration of curcumin and adjuvants or encapsulation of curcumin within the membrane of delivery systems such as liposomes. The impact of AgNPs on phospholipid membrane properties is not clearly understood yet. By applying curcumin as a probe molecule, this work was done to investigate the effect of AgNPs on membrane properties such as permeability and phase transition temperature using 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) liposomes as a model for phospholipids membranes. In addition, cytotoxicity of curcumin and curcumin-AgNPs (cur-AgNPs) was assessed against Human cervical cancer (HeLa) cells. We concluded that AgNPs at low concentration decrease the partition of curcumin into DMPC liposomes by ~ 4-fold. In the presence of AgNPs, curcumin was found to be located close to the stern layer of DMPC liposomes by using a hydrophobic quencher, cetylpyridinium bromide (CPB). In addition, AgNPs broadened the phase transition temperature of DMPC liposomes as it ranged from 20°C to 35°C. Low concentrations