極微弱生物フォトン発光の2次元時・空間特性分析による生体情報抽出法の検討

Abstract

Ultraweak photon emission from biological organisms, commonly referred as biophoton emission, is known to be closely related to vital processes and biological activities, observable quite generally in nature in the absence of any external excitation. The intensity of the photon emission is estimated to be in the order of less than 10-16 W/cm2 on the living surface. The excitation mechanisms of this phenomenon are based on chemical excitation in the living system and considered to originate from internal biochemical reactions associated with metabolic processes. A number of phenomena is indicative the relationship between biophoton emission and physiological and/or pathological conditions. The purpose of our study is to explore the relationship/correlation between physiological state and biophoton emission phenomena so as to extract possible information on the state of biological order and space-time organization of metabolic processes. This paper reports a newly developed technology to measure space-time properties and characterize the dynamics of ultraweak biophoton emission in the single photoelectron counting region. We also describe the spatio-temporal distribution and correlation analysis of ultraweak biophoton emission from soybean seedlings, based on photoelectron pulse time series and position measurement techniques, as a first example. We performed experiments using etiolated soybean seedlings with or without physical (heat, mechanical injury) or chemical (hydrogen peroxide) stimulation. Spatio-temporal response of biophoton emission, indicative of the transmission of some stimulus was observed. In order to clarify the propagation of the response quantitatively, cross-correlation analysis was also carried out. We demonstrate the potential usefulness of a novel two-dimensional photon counting technique to characterize spatio-temporal dynamics of the biophoton emission. From these results, it is our belief that by analyzing the spatio-temporal distribution, spatial and temporal correlation of the biophoton emission, mechanisms of signal transmission within a living system could be explored.