Thermo-triggered Release of CRISPR-Cas9 System by Lipid-Encapsulated Gold Nanoparticles for Tumor Therapy.

CRISPR/Cas9 system is a powerful toolbox for gene editing. However, the low delivery efficiency is still a big hurdle impeding its applications. Herein, we report a strategy to deliver Cas9-sgPlk-1 plasmids (CP) by a multifunctional vehicle for tumor therapy. We condensed CPs on TAT peptide-modified Au nanoparticles (AuNPs/CP, ACP) via electrostatic interactions, and coated lipids (DOTAP, DOPE, cholesterol, PEG2000-DSPE) on the ACP to form lipid-encapsulated, AuNPs-condensed CP (LACP). LACP can enter tumor cells and release CP into the cytosol by laser-triggered thermo-effects of the AuNPs; the CP can enter nuclei by TAT guidance, enabling effective knock-outs of target gene (Plk-1) of tumor (melanoma) and inhibition of the tumor both in vitro and in vivo. This AuNPs-condensed, lipid-encapsulated, and laser-controlled delivery system provides a versatile method for high efficiency CRISPR/Cas9 delivery and targeted gene editing for treatment of a wide spectrum of diseases.

X-ray computed tomography imaging of a tumor with high sensitivity using gold nanoparticles conjugated to a cancer-specific antibody via polyethylene glycol chains on their surface.

Contrast agents are often used to enhance the contrast of X-ray computed tomography (CT) imaging of tumors to improve diagnostic accuracy. However, because the iodine-based contrast agents currently used in hospitals are of low molecular weight, the agent is rapidly excreted from the kidney or moves to extravascular tissues through the capillary vessels, depending on its concentration gradient. This leads to nonspecific enhancement of contrast images for tissues. Here, we created gold (Au) nanoparticles as a new contrast agent to specifically image tumors with CT using an enhanced permeability and retention (EPR) effect. Au has a higher X-ray absorption coefficient than does iodine. Au nanoparticles were supported with polyethylene glycol (PEG) chains on their surface to increase the blood retention and were conjugated with a cancer-specific antibody via terminal PEG chains. The developed Au nanoparticles were injected into tumor-bearing mice, and the distribution of Au was examined with CT imaging, transmission electron microscopy, and elemental analysis using inductively coupled plasma optical emission spectrometry. The results show that specific localization of the developed Au nanoparticles in the tumor is affected by a slight difference in particle size and enhanced by the conjugation of a specific antibody against the tumor.

Targeted tumor delivery and controlled release of neuronal drugs with ferritin nanoparticles to regulate pancreatic cancer progression.

Pancreatic cancer is a lethal malignancy whose progression is highly dependent on the nervous microenvironment. This study develops neural drug-loaded ferritin nanoparticles (Ft NPs) to regulate the nervous microenvironment, in order to control the pancreatic cancer progression. The drug-loaded Ft NPs can target pancreatic tumors via passive targeting of EPR effects of tumors and active targeting via transferrin receptor 1 (TfR1) binding on cancer cells, with a triggered drug release in acidic tumor environment. Two drugs, one activates neural activity (carbachol), the other impairs neural activity (atropine), are encapsulated into the Ft NPs to form two kinds of nano drugs, Nano-Cab NPs and Nano-Ato NPs, respectively. The activation of the nervous microenvironment by Nano-Cab NPs significantly promotes the pancreatic tumor progression, whereas the blockage of neural niche by Nano-Ato NPs remarkably impairs the neurogenesis in tumors and the progression of pancreatic cancer. The Ft-based nanoparticles thus comprise an effective and safe route of delivery of neural drugs for novel anti-cancer therapy.

Development of silica-coated silver iodide nanoparticles and their biodistribution.

Nanomaterials have great potential in the field of medicine and have been studied extensively. In a previous study, we addressed the potential of silver iodide (AgI) as X-ray contrast media, because it possessed high imaging ability in the measurement by X-ray computed tomography (X-CT) in vitro, and its surface can be modified with many functional groups. We developed the method of silica coating to make AgI nanoparticles more stable and uniform in size. However, the safety and metabolism of nanoparticles in vivo remains to be determined. The objective of the present study was to evaluate the in vivo biodistribution of silica-coated AgI nanoparticles (SAgINPs). X-CT, transmission electron microscopy (TEM), and inductively coupled plasma atomic emission spectrometry (ICP-AES) were performed prior to and at intervals following the intravenous administration of SAgINPs to rats and rabbits. ICP-AES is a spectral technique that can determine the presence and concentrations of metal samples. The X-CT study showed long-period enhancement in the liver and spleen, but not in the bladder of rats. The TEM study demonstrated that SAgINPs were found in hepatocytes. Using ICP-AES, Ag was detected in the bile juice of rabbits, but not found in the urine of these animals, suggesting that SAgINPs are excreted via the liver. This study shows the quantitative biodistribution of silica-coated nanoparticles for the first time, indicating that our silica coating technique is useful for development of nanoparticles with hepatic excretion. In conclusion, the SAgINPs may provide X-ray contrast media with high imaging ability and biocompatibility.

Uniform silica coated fluorescent nanoparticles: synthetic method, improved light stability and application to visualize lymph network tracer.

BACKGROUND: The sentinel lymph node biopsy (SLNB) was developed as a new modality in the surgical diagnosis of lymph node metastases. Dye and radioisotope are major tracers for the detection of sentinel lymph nodes (SLN). Dye tends to excessively infiltrate into the interstitium due to their small size (less than several nanometers), resulting in difficulties in maintaining clear surgical fields. Radioisotopes are available in limited number of hospitals. Fluorescent nanoparticles are good candidates for SLN tracer to solve these problems, as we can choose suitable particle size and fluorescence wavelength of near-infrared. However, the use of nanoparticles faces safety issues, and many attempts have been performed by giving insulating coats on nanoparticles. In addition, the preparation of the uniform insulating layer is important to decrease variations in the quality as an SLN tracer. METHODOLOGY/PRINCIPAL FINDINGS: We herein succeeded in coating fluorescent polystyrene nanoparticles of 40 nm with uniform silica layer of 13 nm by the modified Stöber method. The light stability of silica coated nanoparticles was 1.3-fold greater than noncoated nanoparticles. The popliteal lymph node could be visualized by the silica coated nanoparticles with injection in the rat feet. CONCLUSIONS/SIGNIFICANCE: The silica coated nanoparticles in lymph nodes could be observed by transmission electron microscope, suggesting that our silica coating method is useful as a SLN tracer with highly precise distribution of nanoparticles in histological evaluation. We also demonstrated for the first time that a prolonged enhancement of SLN is caused by the phagocytosis of fluorescent nanoparticles by both macrophages and dendritic cells.