Interrelation of physicochemical, spectral, and biological properties of self-organized multi-component aqueous systems based on N-(phosphonomethyl)glycine in the low concentration range

L-Tryptophan Aqueous Systems at Low Concentrations: Interconnection between Self-Organization, Fluorescent and Physicochemical Properties, and Action on Hydrobionts

“…In the vicinity of the threshold concentration of 1 × 10 −6 mol/L, the spectrum shape of the system is close to that of the L -Trp systems at a higher concentration range of 1 × 10 −5 –1 × 10 −4 mol/L [ 2 , 3 ], with maxima at 218 nm and 270–280 nm ( Figure 5 , inset). Starting from the threshold concentration of 1 × 10 −7 mol/L and lower, the spectra have a different appearance characteristic of the previously described BACs systems in similar low concentration ranges where nanoassociates are formed, with a weakly pronounced shoulder at 225 nm and a band in the 250–270 nm interval [ 20 , 36 , 37 , 38 , 39 ].…”

“…Thus, for the L -Trp systems, we can arbitrarily divide the low concentration range into two intervals, characterized by the formation of domains (1 × 10 −7 to 1 × 10 −4 mol/L) and nanoassociates (1 × 10 −2 to 1 × 10 −8 mol/L). Significant changes in the properties of self-organized systems are often observed in the vicinity of c th [ 29 , 36 , 37 , 38 , 39 ].…”

“…The surface tension isotherm of the L -Trp systems in a wider concentration range 1 × 10 −20 –1 × 10 −2 mol/L ( Supplementary Materials, Figure S4 ) presents a non-monotonic decrease in σ not only in the range of nanoassociates formation (1 × 10 −20 to 1 × 10 −8 mol/L), but that of domains as well (1 × 10 −7 –1 × 10 −4 mol/L), with minimum values at the threshold concentration of 1 × 10 −7 mol/L and at 1 × 10 −5 mol/L. Works [ 29 , 38 , 39 ] relate a local decrease of surface tension at certain low concentrations of BACs to the possibility of more pronounced bioeffects at these concentrations, as surface tension is responsible for membranotropic properties of disperse systems, what will be discussed in more detail below.…”

“…The obtained results allowed the authors [ 30 , 31 , 32 , 33 , 34 , 35 ] to assume that the observed spectral properties are a characteristic of the ordered aqueous structures formed in nanoheterogeneous aqueous systems. To support this assumption, similar fluorescence spectra of highly diluted dispersed systems based on some BACs that do not have a pronounced emission capability were obtained [ 36 , 37 , 38 , 39 ].…”

“…In the case of high dilutions (less than 1 × 10 −12 mol/L), the actual concentration of the substance is rather difficult to confirm by experimental methods. Therefore, in our previous papers [ 29 , 36 , 37 , 38 , 39 ], as well as in the present work, when discussing high dilutions corresponding to calculated concentrations from 1 × 10 −13 mol/L to 1 × 10 −20 mol/L, we use this very term implying the theoretically possible concentration of the substance at a corresponding dilution step.…”