Polymerized graphene oxide/MnCe0.5Fe1.5O4 nanoferrofluid as a T2- and T2*-weighted contrast agent for magnetic resonance imaging

Multifunctional Lanthanide-Doped Binary Fluorides and Graphene Oxide Nanocomposites Via a Task-Specific Ionic Liquid

Graphene oxide-based nanocomposites (NCMs) exhibit diverse photonic and biophotonic applications. Innovative nanoengineering using a task-specific ionic liquid (IL), namely, 1-butyl-3-methyl tetrafluoroborate [C₄mim][BF₄], allows one to access a unique class of luminescent nanocomposites formed between lanthanide-doped binary fluorides and graphene oxide (GO). Here the IL is used as a solvent, templating agent, and as a reaction partner for the nanocomposite synthesis, that is, "all three in one". Our study shows that GO controls the size of the NCMs; however, it can tune the luminescence properties too. For example, the excitation spectrum of Ce³⁺ is higher-energy shifted when GO is attached. In addition, magnetic properties of GdF₃:Tb³⁺ nanoparticles (NPs) and GdF₃:Tb³⁺-GO NCMs are also studied at room temperature (300 K) and very low temperature (2 K). High magnetization results for the NPs (e.g., 6.676 emu g^-1 at 300 K and 184.449 emu g^-1 at 2 K in the applied magnetic field from +50 to -50 kOe) and NCMs promises their uses in many photonic and biphotonic applications including magnetic resonance imaging, etc.

Graphene oxide induces autophagy and apoptosis via ROS-dependent AMPK/mTOR/ULK-1 pathway in colorectal cancer cells

Aim: To investigate the anticancer effects and action mechanism of graphene oxide (GO) in colorectal cancer (CRC). Materials & methods: Anticancer effects and mechanisms of GO in CRC were investigated both in vivo and in vitro. Results: GO significantly inhibited tumor growth both in vitro and in vivo. GO was able to enter HCT116 cells through endocytosis. GO treatment resulted in cytotoxicity, reactive oxygen species (ROS) production, apoptosis, autophagy and activation of the AMPK/mTOR/ULK1 signal pathway. However, ROS scavenger N-acetylcysteine (NAC) attenuated the above effects and restored the effects of GO on protein expressions related to apoptosis, autophagy and AMPK/mTOR/ULK1 signal pathways. Conclusion: GO exerts anticancer effects against CRC via ROS-dependent AMPK/mTOR/ULK-1 pathway-related autophagy and apoptosis.

Photoluminescent biodegradable polyorganophosphazene: A promising scaffold material for in vivo application to promote bone regeneration

Tissue engineering scaffolds made of conventional aliphatic polyesters are inherently non-fluorescent, which results in their in vivo degradation hard to be visualized. Photoluminescent biodegradable polyorganophosphazenes (PPOPs) are synthesized by introducing fluorophores onto the polyphosphazene backbone via nucleophilic substitution reaction. In this study, a fluorophore (termed as TPCA), derived from citric acid and 2-aminoethanethiol, was co-substituted with alanine ethyl ester onto the polyphosphazene backbone to obtain a photoluminescent biodegradable POPP (termed as PTA). The scaffolds made of PTA demonstrated non-cytotoxicity and cell affinity, particularly, capacity in promoting osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs). In vivo evaluations using the rat calvarial defect model confirmed its strong potential in enhancing osteogenesis, more importantly, the in vivo degradation of the PTA scaffold could be monitored via its fluorescence intensity alongside implantation time.