Gene Regulation by Intracellular Delivery and Photodegradation of Nanoparticles Containing Small Interfering RNA

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.

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.