In situ synthesis of graphene oxide/gold nanorods theranostic hybrids for efficient tumor computed tomography imaging and photothermal therapy

Graphene oxide/gold nanorod （GO/GNR） nanohybrids were synthesized with a GO- and gold-seed-mediated in situ growth method at room temperature by mixing polystyrene sulfonate （PSS） functionalized GO, secondary growth solution, and gold seeds. Compared with ex situ preparation methods of GO/GNRs or graphene （G）/GNRs, the in situ synthesis of GO/GNRs addressed the issue of the aggregation of the GNRs before their attachment onto the GO. The method is straightforward and environment-friendly; The GO/GNRs showed a remarkable photothermal effect in vitro. The temperature of the GO/GNR nanohybrids increased from 25 to 49.9 ℃ at a concentration of 50 μg/mL after irradiation with an 808-nm laser （0.4 W/cm2） for 6 min. Additionally; the GO/GNRs exhibited good optical and morphological stability and photothermal properties after six cycles of laser irradiation. Upon injection of the GO/GNRs into xenograft tumors, excellent computed tomography （CT） imaging properties and photothermal effect were obtained. The preclinical CT agent iohexol was combined with the GO/GNRs and further enhanced CT imaging. Therefore, the GO/GNR nanohybrids have great potential for predse CT-image-guided tumor photothermal treatment.

Fabrication of N-acetyl-L-cysteine-capped CdSe-polyelectrolytes @ Hydroxyapatite Composite Microspheres for Fluorescence Detection of Cu^(2+) Ions

N-Acetyl-L-cysteine-capped CdSe-polyelectrolytes @ hydroxyapatite （NAC-CdSe-PEs@HA） composite microspheres were fabricated through a stepwise layer-by-layer method and used for fluorescence detection of Cu2＋ ions. The hollow HA microsphere was confirmed to be an ideal host to load CdSe quantum dots （QDs） due to their large surface area, well-defined porous structure, and large inner hollow size. Furthermore, the introduction of polyelectrolyte layers contributed to the increase of the loading amount and the electrostatic interaction between microsphere and QDs. Experiments results showed that among various metal ions investigated, Cu2＋ exhibited the highest quenching effect on the fluorescence of CdSe QDs loaded in the composite microspheres. Additionally, the composite exhibited improved sensibility in detecting Cu2＋ due to the presence of HA microspheres. Importantly, it is easy to separate and recycle the composite microspheres from the detection solution due to their relatively large size and high stability, thereby avoiding secondary contamination.