Development of reliable vectors is a major challenge in gene therapy. Previous gene transfer methods using non-viral vectors, such as liposomes or nanoparticles, have resulted in relatively low levels (35 to approximately 50%) of gene expression. We have developed a silicon nanoparticle (SNAP) system, a novel non-viral vector, for DNA transfer into cells. SNAP was synthesized chemically and modified with sodium chloride or sodium iodide. Electronmicroscopy of SNAP and fluorescence microscopy of fluorescence-labeled SNAP revealed that they were generated uniformly, had diameters of 10-100 nm, and showed a better efficiency (about 70%) of DNA transfection into cells as well as protection of DNA against degradation. The microscopy also demonstrated the adhesion of SNAP with HT1080 cell surface and entry of SNAP into the cells without cytotoxicity. Intravenous and/or intra-abdominal administration of the SNAP to mice revealed the accumulation of SNAP in the cells of the brain, liver, spleen, lung, kidney, intestine, prostate and the testis without any pathological cell changes or mortality, suggesting that they passed through the blood-brain, blood-prostate, and blood-testis barriers. These findings indicate that the SNAP generated has good biological characteristics as a potential promising vector for gene transfer, gene therapy and drug delivery.

A phase I/II clinical trial for treating malignant melanoma by boron neutron capture therapy (BNCT) was designed to evaluate whether the world’s first in-hospital neutron irradiator (IHNI) was qualified for BNCT. In this clinical trial planning to enroll 30 patients, the first case was treated on August 19, 2014. We present the protocol of this clinical trial, the treating procedure, and the clinical outcome of this first case. Only grade 2 acute radiation injury was observed during the first four weeks after BNCT and the injury healed after treatment. No late radiation injury was found during the 24-month follow-up. Based on positron emission tomography-computed tomography (PET/CT) scan, pathological analysis and gross examination, the patient showed a complete response to BNCT, indicating that BNCT is a potent therapy against malignant melanoma and IHNI has the potential to enable the delivery of BNCT in hospitals.

The imaging of sentinel lymph nodes (SLNs), the first defense against primary tumor metastasis, has been considered as an important strategy for noninvasive tracking tumor metastasis in clinics. In this study, we developed an imaging contrast system based on fluorescent dye-loaded mesoporous silica nanoparticles (MSNPs) that integrate near-infrared (NIR) fluorescent and photoacoustic (PA) imaging modalities for efficient SLN mapping. By balancing the ratio of dye and nanoparticles for simultaneous optimization of dual-modality imaging (NIR and PA), the dye encapsulated MSNP platform was set up to generate both a moderate NIR emission and PA signals simultaneously. Moreover, the underlying mechanisms of the relevance between optical and PA properties were discovered. Subsequently, dual-modality imaging was achieved to visualize tumor draining SLNs up to 2 weeks in a 4T1 tumor metastatic model. Obvious differences in uptake rate and contrast between metastatic and normal SLNs were observed both in vivo and ex vivo. Based on all these imaging data, it was demonstrated that the dye-loaded MSNPs allow detection of regional lymph nodes in vivo with time-domain NIR fluorescent and PA imaging methods efficiently.

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