Surface modification of silica nanoparticles using 4-aryloxy boron dipyrromethene (BODIPY) enhances skin permeation

4-Aryloxy boron dipyrromethene (BODIPY) modification of the surface of silica nanoparticles (NPs) improved permeability through the membrane of HaCaT skin cells and swine skin tissue. The 35 nm BODIPY-modified NPs penetrated tape-stripped skin and reached the dermis within 1 h. Since these NPs can encapsulate a variety of molecules including macromolecules, they are expected to serve as effective carriers for the delivery of drugs, genes, and other compounds through skin and into cells.

A light sensitive self-assembled nanogel as a tecton for protein patterning materials

A self-assembled nanogel is constructed from light-sensitive cholesteryl pullulan (Ls-CHP) by using photo-labile ortho-nitrobenzyl (o-NB) units. The nanogel-based film is obtained by evaporation of an Ls-CHP nanogel solution. Exposure of the resulting nanogel-based film to light with a mask resulted in a patterned film that can encapsulate FITC-insulin.

Development of analytical methods for functional analysis of intracellular protein using signal-responsive silica or organic nanoparticles

Because proteins control cellular function, intracellular protein analysis is needed to gain a better understanding of life and disease. However, in situ protein analysis still faces many difficulties because proteins are heterogeneously located within the cell and the types and amount of proteins within the cell are ever changing. Recently, nanotechnology has received increasing attention and multiple protein-containing nanoparticles have been developed. Nanoparticles offer a promising tool for intracellular protein analysis because (1) they can permeate the cellular membrane after modification or changing composition, (2) the stability of various proteins is improved by encapsulation within nanoparticles, and (3) protein release and activity can be controlled. In this review, we discuss the development of analytical methods for intracellular functional protein analysis using signal-responsive silica and organic nanoparticles.

γ-PARCEL: Control of Molecular Release Using γ-Rays

We previously have developed the photoresponsive tetra-gel and nanoparticles for controlling the function of the encapsulated substance by UV irradiation. However, the penetration ability of the UV is not high enough. Here, we developed a radiation-responsive tetra-gel and nanoparticle based on γ-ray-responsive X-shaped polyethylene glycol (PEG) linker with a disulfide bond. The nanoparticle could retain small molecules and biomacromolecules. γ-Rays were used as a trigger signal because of their higher penetrating ability. This allowed a spatiotemporal release and control of the encapsulated substances from the nanoparticle in the deeper region, which is impossible by using light exposure (ultraviolet, visible, and near-infrared).

Simultaneous analysis of nanoparticles and small molecules by high-performance liquid chromatography using a silica monolithic column

A high-performance liquid chromatography method using a commercially available silica monolithic column for the simultaneous analysis of nanoparticles and small molecules was developed. The method uses the micrometer-sized flow-through pores and nanometer-sized mesopores of the monolithic column for separation: first, size separation of nanoparticles was performed by the micrometer-sized pores using the hydrodynamic mode, and then small molecules were separated by the nanometer-sized pores using the normal-phase mode. The method was used to evaluate and compare three existing methods for purifying nanoparticles and to analyse nanoparticle stability. The bimodal structure of the monolithic column is promising for the simultaneous separation of nanoparticles and small molecules.

Spatiotemporal activation of molecules within cells using silica nanoparticles responsive to blue-green light

Vehicle-nanoparticles that release cargo molecule at the cytoplasm of live cells by blue-green light has been developed.

Surfactant-free aqueous preparation from a star polymer of size-controlled nanoparticles with encapsulated functional molecules

A simple preparation method for size-controlled nanoparticles with encapsulated functional molecules in a surfactant-free aqueous condition.

MR imaging techniques for nano-pathophysiology and theranostics

The advent of nanoparticle DDSs (drug delivery systems, nano-DDSs) is opening new pathways to understanding physiology and pathophysiology at the nanometer scale. A nano-DDS can be used to deliver higher local concentrations of drugs to a target region and magnify therapeutic effects. However, interstitial cells or fibrosis in intractable tumors, as occurs in pancreatic or scirrhous stomach cancer, tend to impede nanoparticle delivery. Thus, it is critical to optimize the type and size of nanoparticles to reach the target. High-resolution 3D imaging provides a means of "seeing" the nanoparticle distribution and therapeutic effects. We introduce the concept of "nano-pathophysiological imaging" as a strategy for theranostics. The strategy consists of selecting an appropriate nano-DDS and rapidly evaluating drug effects in vivo to guide the next round of therapy. In this article we classify nano-DDSs by component carrier materials and present an overview of the significance of nano-pathophysiological MRI.

A computer simulation of the networked structure of a hydrogel prepared from a tetra-armed star pre-polymer

We used a coarse-grained (CG) molecular dynamics model with potentials convertible to actual units to simulate the polymerization of a gel of a tetra-armed poly(ethylene glycol) derivative (MW ≈ 6000) under aqueous conditions and analysed its three-dimensional network structure. The radius of gyration of individual pre-polymers after gelation was slightly increased compared with that of the single pre-polymer before gelation, and its distribution was broad, attributable to inter- and intra-molecular bonds. The largest pores in the unit cell were about 3.5-3.9 nm. The existence of large pores seems to explain the protein encapsulation capability of and protein leakage from the gel indicating that the CG simulation, which maintains information about potentials in actual units, is an effective tool for investigating gel properties that are difficult to measure in real experiments.

Development of a spatiotemporal method to control molecular function by using silica-based photodegradable nanoparticles

Novel silica-based photodegradable nanoparticles were developed. The nanoparticle is a useful tool for the spatiotemporal control of various molecular functions because they permit the quick and transient release of encapsulated molecules after short-term irradiation.

Delivery, stabilization, and spatiotemporal activation of cargo molecules in cells with positively charged nanoparticles

Positively charged photodegradable nanoparticles that simultaneously encapsulated various compounds including small and large molecules were prepared. The nanoparticles were internalized to the cell by endocytosis and were stable within the cells for at least 4 days. The encapsulated molecules were released into the cytosol using light stimuli.