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Graphical abstract Abstract Graphene oxide (GO), as a drug delivery carrier, has attracted considerable attention because of its interesting properties. However, GO tends to aggregate in aqueous solution. Amphiphilic molecules are usually necessary to stabilize GO. The introduction of these non-functional macromolecules on the one hand reduces drug loading, but on the other hand may cause unpredictable side effects. This study proposes a new strategy for stabilizing GO with a functional photothermal agent, IR820 (new indocyanine green) derivative. IR820 derivative results from the conjugation of active targeted lactobionic acid (LA) with IR820 for the formation of IR820-LA. IR820-LA features central aromatic groups that can associate with the GO basal plane through π-π interactions. The flanking moiety of hydrophilic LA and sulfonic groups thus provides steric stabilization of GO in aqueous solution. Moreover, IR820-LA endows GO/doxorubicin (GO/DOX) nanovehicles with fluorescence imaging ability and actively targeted chemo-photothermal therapy. Experimental results both in vitro and in vivo have indicated its good chemo-photothermal therapeutic effect according to its active tumor targeting ability and pH-sensitive drug release characteristics. Therefore, our GO/DOX/IR820-LA nanohybrids can be excellent nanoplatforms for active tumor-targeted chemo-photothermal therapy with imaging guidance. [ABSTRACT FROM AUTHOR]

Abstract: Zwitterionic diazeniumdiolate, a nitric oxide precursor, was dissolved in basic buffer solution (pH=9.0) and encapsulated in thermo-sensitive liposomes composed of phospholipids of different sensitive temperatures. The basic intra-liposomal environment dramatically delayed spontaneous NO release. When the liposomes were placed in physiological buffer solution and temperatures were increased to the sensitive temperatures of the phospholipids’ membranes, extra-liposomal protons started to influx to collapse the pH gradient and subsequently induce a significant NO release. Moreover, the presence of a stronger pH gradient when the liposomes were applied to a more acidic environment caused a higher proton influx driving force to trigger the influx of protons and, subsequently, NO release. In this work, we demonstrate that thermo-sensitive liposomes can be used to create a stable pH gradient in a nanoenvironment entrapping zwitterionic diazeniumdiolate for sustained and heat/acid-activated NO release. [Copyright &y& Elsevier]