These authors contributed equally to this work.

A two-dimensional, glycopolymer-immobilized, photonic crystal (PhC) biosensor was developed for the detection of proteins.

We developed a novel protease assay device using nanoimprinted two-dimensional photonic crystal (2D-PhC) for the first time. 2D-PhC exhibits a characteristic reflection, and its intensity is strongly affected by small changes in refractive index (RI) of the 2D-PhC surface. In this study, protease substrate-immobilized 2D-PhC was newly developed in order to measure the protease activity, and the simple and selective detection of protease activity using 2D-PhC was successfully performed.

The use of naked unmodified small interfering RNA (N-siRNA) without vector has previously been investigated as a pulmonary therapy. However, little is known regarding stabilities and aerodynamic particle sizes of N-siRNA-containing droplets; nebulizers have not yet been optimized for N-siRNA solutions. Thus, in this study, we investigated the feasibility of inhaled N-siRNA solutions for pulmonary therapy using nebulization. Various nebulizers and N-siRNA concentrations were assessed in terms of siRNA integrity after nebulization, and inhalation properties including aerodynamic particle size were examined. In comparison with ultrasonic-, air-jet-, and vibrating-mesh nebulizers, N-siRNA integrity was not affected by nebulization. Thus, in further experiments, performances of N-siRNA aerosols with different nebulizers and N-siRNA concentrations were evaluated and screened using an aerodynamic particle sizer (APS) which employed the time-of-flight principle or a cascade impactor. Mean mass aerodynamic diameters of N-siRNA-containing droplets from vibrating-mesh nebulizers tended to decrease with increasing N-siRNA concentrations, reflecting the influence of N-siRNA solutions on surface tension, as indicated by contact angles. These data indicate the utility of APS instruments for investigating the nebulized characteristics of expensive drugs including siRNAs and may facilitate the development of N-siRNA inhalation formulations.Key words small interfering RNA (siRNA); vibrating-mesh nebulizer; aerodynamic particle size; surface tension; contact angle Small interfering RNA (siRNA) has a great therapeutic potential as a tool for the post-transcriptional silencing of target gene expression. 1) Recently, the field of siRNA delivery has rapidly progressed, and the local pulmonary delivery of siRNA has been investigated for various lung diseases. 2,3)Inhalation is the most popular noninvasive method for delivering therapeutic siRNA agents to the lungs 4); local siRNA inhalation therapy reduced virus titers in the lung and attenuated local pulmonary chemokine production after acute lung injury and infection.5,6) However, naked (unmodified) siRNA (N-siRNA) is susceptible to nuclease degradation; siRNA delivery systems facilitating gene silencing efficiency, including those using cationic materials, can have cytotoxic effects. N-siRNA has been delivered with some success to the lung, although systemic delivery of N-siRNA generally fails to produce significant gene silencing effects.3,7) N-siRNA lacks delivery vectors that produce toxicity and inflammation; thus, N-siRNA formulation for pulmonary delivery offers advantages for safety and simplicity. However, few developments of N-siRNA formulations have been reported. Direct pulmonary N-siRNA delivery has been achieved in humans following the inhalation of aerosols generated by inhalers or nebulizers. Three types of inhalation devices are currently available for pulmonary drug delivery, including metered dose inhalers, dry powder inhalers, and nebulizers. Liquid nebulization e...