Jing Yu

Multifunctional Fe5C2 Nanoparticles: A Targeted Theranostic Platform for Magnetic Resonance Imaging and Photoacoustic Tomography‐Guided Photothermal Therapy

Fe5 C2 NPs exhibit a high contrast in magnetic resonance imaging (MRI), superior photoacoustic tomography improvements, and efficient photothermal therapy (PTT) due to their unique core/shell structure, with a magnetic core and carbon shell. By conjugating a new class of affinity proteins (ZHER2:342), they can target to tumor cells with low cytotoxicity, and kill them through laser irritation. It is also possible to ablate tumors under guidance by MRI and PTT without noticeable side effects.

Multistimuli-Regulated Photochemothermal Cancer Therapy Remotely Controlled via Fe5C2 Nanoparticles

Stimuli-controlled drug delivery and release is of great significance in cancer therapy, making a stimuli-responsive drug carrier highly demanded. Herein, a multistimuli-controlled drug carrier was developed by coating bovine serum albumin on Fe5C2 nanoparticles (NPs). With a high loading of the anticancer drug doxorubicin, the nanoplatform provides a burst drug release when exposed to near-infrared (NIR) light or acidic conditions. In vitro experiment demonstrated a NIR-regulated cell inhibition that is ascribed from cellular uptake of the carrier and the combination of photothermal therapy and enhanced drug release. The carrier is also magnetic-field-responsive, which enables targeted drug delivery under the guidance of a magnetic field and monitors the theranostic effect by magnetic resonance imaging. In vivo synergistic effect demonstrates that the magnetic-driven accumulation of NPs can induce a complete tumor inhibition without appreciable side effects to the treated mice by NIR irradiation, due to the combined photochemotherapy. Our results highlight the great potential of Fe5C2 NPs as a remote-controlled platform for photochemothermal cancer therapy.

Hollow manganese phosphate nanoparticles as smart multifunctional probes for cancer cell targeted magnetic resonance imaging and drug delivery

AbstractMultifunctional probes for simultaneous magnetic resonance imaging (MRI) and drug delivery have attracted considerable interest due to their promising potential applications in the early-stage diagnosis and therapy of the diseases. In this study, hollow manganese phosphate nanoparticles (HMP NPs) with an average diameter of 18 nm were synthesized and aminated through silanization, which enabled the covalent conjugation of biocompatible poly(ethylene glycol) (PEG) on their surfaces. The anti-tumor drug doxorubicin (DOX) could be loaded into the hollow cavities. Under physiological conditions (pH 7.4), the NPs showed low MRI T1 contrast (r1 = 1.19 L·mmol−1·s−1), whereas high T1 enhancement (r1 = 5.22 L·mmol−1·s−1) was achieved after dissolving them in endosome/lysosome mimetic conditions (pH 5.4). This is due to the fact that the NPs were easily eroded, which resulted in the release of Mn2+ at low pH. To use this interesting phenomenon for targeted DOX drug delivery, we conjugated the tumor-targeting ligand folic acid (FA) on HMP NPs and investigated their drug delivery capacity and cytotoxicity to cell lines expressing different amount of folate receptor (FR). KB cells showed more significant cellular uptake than HeLa cells and A549 cells, as confirmed by confocal laser scanning microscopy (CLSM), flow cytometry and cellular T1-weighted MRI. Furthermore, the drug-loaded HMP NPs exhibited greater cytotoxicity to KB cells. Our results suggest that functionalized HMP NPs can act as an effective multifunctional probe for selective diagnosis with MRI, as well as giving efficient targeted drug delivery.

Monodisperse Au–Fe2C Janus Nanoparticles: An Attractive Multifunctional Material for Triple-Modal Imaging-Guided Tumor Photothermal Therapy

Imaging-guided photothermal therapy (PTT) by combination of imaging and PTT has been emerging as a promising therapeutic method for precision therapy. However, the development of multicomponent nanoplatforms with stable structures for both PTT and multiple-model imaging remains a great challenge. Herein, we synthesized monodisperse Au-Fe2C Janus nanoparticles (JNPs) of 12 nm, which are multifunctional entities for cancer theranostics. Due to the broad absorption in the near-infrared range, Au-Fe2C JNPs showed a significant photothermal effect with a 30.2% calculated photothermal transduction efficiency under 808 nm laser irradiation in vitro. Owing to their excellent optical and magnetic properties, Au-Fe2C JNPs were demonstrated to be advantageous agents for triple-modal magnetic resonance imaging (MRI)/multispectral photoacoustic tomography (MSOT)/computed tomography (CT) both in vitro and in vivo. We found that Au-Fe2C JNPs conjugated with the affibody (Au-Fe2C-ZHER2:342) have more accumulation and deeper penetration in tumor sites than nontargeting JNPs (Au-Fe2C-PEG) in vivo. Meanwhile, our results verified that Au-Fe2C-ZHER2:342 JNPs can selectively target tumor cells with low cytotoxicity and ablate tumor tissues effectively in a mouse model. In summary, monodisperse Au-Fe2C JNPs, used as a multifunctional nanoplatform, allow the combination of multiple-model imaging techniques and high therapeutic efficacy and have great potential for precision theranostic nanomedicines.

Multifunctional metal rattle-type nanocarriers for MRI-guided photothermal cancer therapy.

In the past decade, numerous species of nanomaterials have been developed for biomedical application, especially cancer therapy. Realizing visualized therapy is highly promising now because of the potential of accurate, localized treatment. In this work, we first synthesized metal nanorattles (MNRs), which utilized porous gold shells to carry multiple MR imaging contrast agents, superparamagnetic iron oxide nanoparticles (SPIONs), inside. A fragile wormpore-like silica layer was manipulated to encapsulate 8 nm oleylamine SPIONs and mediate the in situ growth of porous gold shell, and it was finally etched by alkaline solution to obtain the rattle-type nanostructure. As shown in the results, this nanostructure with unique morphology could absorb near-infrared light, convert to heat to kill cells, and inhibit tumor growth. As a carrier for multiple SPIONs, it also revealed good function for T2-weighted MR imaging in tumor site. Moreover, the rest of the inner space of the gold shell could also introduce potential ability as nanocarriers for other cargos such as chemotherapeutic drugs, which is still under investigation. This metal rattle-type nanocarrier may pave the way for novel platforms for cancer therapy in the future.

Fe5C2 nanoparticles: a reusable bactericidal material with photothermal effects under near-infrared irradiation

Hägg iron carbide (Fe5C2) was synthesized through a facile one-pot wet-chemical route and employed as a photothermal agent to inactivate bacterial cells. The as-prepared Fe5C2 nanoparticles (NPs) were about 20 nm in diameter, and exhibited strong magnetic properties (Ms = 122 emu g-1 at 298 K). Fe5C2 NPs exhibited excellent antibacterial capability toward both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) under near-infrared (NIR) irradiation. Under NIR irradiation, complete inactivation of E. coli and S. aureus cells (about 2 × 106 CFU per mL) could be obtained by 50 mg L-1 Fe5C2 NPs in 60 min and 150 min, respectively. Humic acid (HA) slightly inhibited the disinfection efficiency of Fe5C2 NPs, however, more than 99.9% of E. coli cells were inactivated in 60 min even when the concentration of HA was as high as 10 mg L-1. Complete disinfection of E. coli cells could be achieved with the presence of 10 mg L-1 HA by increasing the reaction time to 90 min. Moreover, Fe5C2 NPs showed great reusability, and complete disinfection of E. coli cells remained even after five consecutive reuse cycles. The increase in temperature of bacterial suspension caused by the photothermal effect of Fe5C2 NPs was determined to be the main reason for the inactivation of bacteria. Our study showed that Fe5C2 NPs have great application potential for bacterial disinfection in water.

Overestimated value of 18F-FDG PET/CT to diagnose pulmonary nodules: Analysis of 298 patients

AIM To investigate the accuracy and efficacy of combined 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) in the diagnosis of pulmonary nodules. MATERIAL AND METHODS The present retrospective study included 298 patients with clinically suspected pulmonary malignancy who underwent preoperative PET/CT. The results of PET/CT were compared with the histopathological findings after thoracotomy or thoracoscopic surgery. RESULTS Of 298 patients, pulmonary malignancy was histopathologically diagnosed in 248 and benign lesions in 50 patients. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT in detecting malignant lesions were 80.2%, 38%, 86.5%, 27.9%, and 73.1%, respectively. The specificity and NPV were very low, and the area under curve (AUC) in the receiver operating characteristic (ROC) curve analysis was 0.694. For 219 patients with non-small cell lung cancer (NSCLC), falsely negative results occurred in 43 patients. The multivariate risk-factor analysis identified high differentiation (p < 0.001), peripheral lung cancer (p = 0.016), non-pleural invasion (p = 0.001), tumour size ≤3 cm (p = 0.026), adenocarcinoma (p = 0.062) and non-smoker (p = 0.066) as risk factors for false negatives.. CONCLUSION The study suggests that the role of PET/CT in the detection of pulmonary malignancy has been overestimated in the past. It warrants attention that high differentiation, peripheral lung cancer, non-pleural invasion, tumour size ≤3 cm, adenocarcinoma, and non-smoker were independent risk factors for negative PET/CT findings of NSCLC..

Iron carbide nanoparticles: an innovative nanoplatform for biomedical applications

Iron carbide nanoparticles (ICNPs) are nano-intermetallic compounds that consist of iron and carbon. Benefiting from the magnetic and chemical activity of iron, and/or mechanical strength and chemical inertness of carbon, they have been widely applied in energetic and biomedical-related fields. Particularly in biomedicine, ICNPs have shown high colloidal stability and good performance in magnetic-dependent diagnosis and therapies such as magnetic resonance imaging (MRI) and magnetic hyperthermia (MH), due to their high magnetization and moderate coercivity. The carbon content protects ICNPs from oxidation and corrosion (ion release), which prolongs their life time and reduces their toxicity in physiological environments, and endows nanoparticles (NPs) with high performance in carbon-relevant theranostics as well. On this basis, ICNPs have great promise in multi-modal imaging or imaging-guided tumor-selective therapy to realize precise diagnoses with mild side effects. This paper aims to cover the state of the art applications of ICNPs in biomedicine, primarily including MRI, MH, magnetic targeting (MT), magnetic separation (MS), photothermal therapy (PTT) and photoacoustic tomography (PAT). The biocompatibility of ICNPs is also addressed.

Exchange‐Coupled fct‐FePd/α‐Fe Nanocomposite Magnets Converted from Pd/Fe3O4 Core/Shell Nanoparticles

We report the controlled synthesis of exchange-coupled face-centered tetragonal (fct) FePd/α-Fe nanocomposite magnets with variable Fe concentration. The composite was converted from Pd/Fe3O4 core/shell nanoparticles through a high-temperature annealing process in a reducing atmosphere. The shell thickness of core/shell Pd/Fe3O4 nanoparticles could be readily tuned, and subsequently the concentration of Fe in nanocomposite magnets was controlled. Upon annealing reduction, the hard magnetic fct-FePd phase was formed by the interdiffusion between reduced α-Fe and face-centered cubic (fcc) Pd, whereas the excessive α-Fe remained around the fct-FePd grains, realizing exchange coupling between the soft magnetic α-Fe and hard magnetic fct-FePd phases. Magnetic measurements showed variation in the magnetic properties of the nanocomposite magnets with different compositions, indicating distinct exchange coupling at the interfaces. The coercivity of the exchange-coupled nanocomposites could be tuned from 0.7 to 2.8 kOe and the saturation magnetization could be controlled from 93 to 160 emu g(-1). This work provides a bottom-up approach using exchange-coupled nanocomposites for engineering advanced permanent magnets with controllable magnetic properties.

One-pot synthesis of hollow/porous Mn-based nanoparticles via a controlled ion transfer process.

A general one-pot protocol is reported to prepare hollow or porous manganese (Mn) oxide, phosphate, sulfide nanoparticles (NPs) via a controlled ion transfer process.