Recently, M13 bacteriophage has started to be widely used as a functional nanomaterial for various electrical, chemical, or optical applications, such as battery components, photovoltaic cells, sensors, and optics. In addition, the use of M13 bacteriophage has expanded into novel research, such as exciton transporting. In these applications, the versatility of M13 phage is a result of its nontoxic, self-assembling, and specific binding properties. For these reasons, M13 phage is the most powerful candidate as a receptor for transducing chemical or optical phenomena of various analytes into electrical or optical signal. In this review, we will overview the recent progress in optical sensing applications of M13 phage. The structural and functional characters of M13 phage will be described and the recent results in optical sensing application using fluorescence, surface plasmon resonance, Förster resonance energy transfer, and surface enhanced Raman scattering will be outlined.

[Purpose] A scalp massage was conducted on female office workers divided into a 15 minute group and 25 minute group and its effect on stress hormone, blood pressure and heart rate was analyzed in order to provide a theoretical rationale to apply scalp massage as stress therapy. [Subjects and Methods] A scalp massage was applied to 34 female office workers twice a week for a total of 10 weeks; the subjects were classified into 15 min., 25 min. and control groups, and their stress hormone levels, blood pressure and heart rate were evaluated. [Results] Significant differences in norepinephrine, cortisol and blood pressure (SBP & DBP) were found in terms of interaction by time interval and between groups. [Conclusion] As a result of applying scalp massage to female office workers for 15 and 25 minutes, positive effects were observed on stress hormone, blood pressure and heart rate. Therefore, scalp massage can be used for stress control with no spatial or time limit.

A new potassium ion detection assay was developed using a dye‐labeled aptamer and conjugated polyelectrolyte (CPE) as a signaling platform via 1‐step and 2‐step fluorescence resonance energy transfer. Guanine‐rich K+‐specific aptamers were designed as K+ ion recognition species with 6‐carboxyfluorescein (6‐FAM) and 6‐carboxytetramethylrhodamine (6‐TAMRA) at both termini. In the presence of K+ ions, the aptamers undergo a conformational change from an unfolded to folded form by forming a G‐quadruplex with K+, bringing two dyes in proximity. FRET‐induced 6‐TAMRA emission was proportional to [K+] in a range of 22.5 μm–100 mm in water without interference by the presence of excess Na+ ions (100 mm). Upon the addition of CPE, a two‐step FRET process from CPE to 6‐TAMRA via 6‐FAM was enabled, showing an intensified 6‐TAMRA signal with K+ ions. The dynamic detection range and limit of detection (LOD) was fine‐tuned from ∼millimolar to ∼nanomolar concentrations of K+ by modulating the signal amplification effect of CPE. The LOD was determined to be ≈3.0 nm. This detection assay also showed high selectivity against other metal ions. This sensing scheme can be extended to the detection of a wide range of target materials by simply modifying the recognition aptamer sequence.

We find that the exciton dipole-dipole interaction in a single laterally coupled GaAs/AlGaAs quantum dot structure can be controlled by the linear polarization of a nonresonant optical excitation. When the excitation intensity is increased with the linearly polarized light parallel to the lateral coupling direction [11̅0], excitons (X and X) and local biexcitons (XX and XX) of the two separate quantum dots (QD and QD) show a redshift along with coupled biexcitons (XX), while neither coupled biexcitons nor a redshift are observed when the polarization of the exciting beam is perpendicular to the coupling direction. The polarization dependence and the redshift are attributed to an optical nonlinearity in the exciton Förster resonant energy transfer interaction, whereby exciton population transfer between the two quantum dots also becomes significant with increasing excitation intensity. We have further distinguished coupled biexcitons from local biexcitons by their large diamagnetic coefficient.

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