A simple synthetic route for the preparation of functional nanoscale graphene oxide (NGO), a novel nanocarrier for the loading and targeted delivery of anticancer drugs, is reported. The NGO is functionalized with sulfonic acid groups, which render it stable in physiological solution, followed by covalent binding of folic acid (FA) molecules to the NGO, thus allowing it to specifically target MCF-7 cells, human breast cancer cells with FA receptors. Furthermore, controlled loading of two anticancer drugs, doxorubicin (DOX) and camptothecin (CPT), onto the FA-conjugated NGO (FA-NGO) via pi-pi stacking and hydrophobic interactions is investigated. It is demonstrated that FA-NGO loaded with the two anticancer drugs shows specific targeting to MCF-7 cells, and remarkably high cytotoxicity compared to NGO loaded with either DOX or CPT only. Considering that the combined use of two or more drugs, a widely adopted clinical practice, often displays much better therapeutic efficacy than that of a single drug, the controlled loading and targeted delivery of mixed anticancer drugs using these graphene-based nanocarriers may find widespread application in biomedicine.

Release of ATP from astrocytes is required for Ca2+ wave propagation among astrocytes and for feedback modulation of synaptic functions. However, the mechanism of ATP release and the source of ATP in astrocytes are still not known. Here we show that incubation of astrocytes with FM dyes leads to selective labelling of lysosomes. Time-lapse confocal imaging of FM dye-labelled fluorescent puncta, together with extracellular quenching and total-internal-reflection fluorescence microscopy (TIRFM), demonstrated directly that extracellular ATP or glutamate induced partial exocytosis of lysosomes, whereas an ischaemic insult with potassium cyanide induced both partial and full exocytosis of these organelles. We found that lysosomes contain abundant ATP, which could be released in a stimulus-dependent manner. Selective lysis of lysosomes abolished both ATP release and Ca2+ wave propagation among astrocytes, implicating physiological and pathological functions of regulated lysosome exocytosis in these cells.

Enhanced near-field at noble metal nanoparticle surfaces due to localized surface plasmon resonance (LSPR) has been researched in fields ranging from biomedical to photoelectrical applications. However, it is rarely explored on nonmetallic nanomaterials discovered in recent years, which can also support LSPR by doping-induced free charge carriers, let alone the investigation of an intricate system involving both. Here we construct a dual plasmonic hybrid nanosystem Au-Cu9S5 with well controlled interfaces to study the coupling effect of LSPR originating from the collective electron and hole oscillations. Cu9S5 LSPR is enhanced by 50% in the presence of Au, and the simulation results confirm the coupling effect and the enhanced local field as well as the optical power absorption on Cu9S5 surface. This enhanced optical absorption cross section, high photothermal transduction efficiency (37%), large light penetration depth at 1064 nm, excellent X-ray attenuation ability, and low cytotoxicity enable Au-Cu9S5 hybrids for robust photothermal therapy in the second near-infrared (NIR) window with low nanomaterial dose and laser flux, making them potential theranostic nanomaterials with X-ray CT imaging capability. This study will benefit future design and optimization of photoabsorbers and photothermal nanoheaters utilizing surface plasmon resonance enhancement phenomena for a broad range of applications.