The Influence of the Composition of Subphase and External Conditions on the Formation and Properties of Langmuir Monolayer
The specifity of the formation of arachinic acid monolayers (used as models of cell membranes) by the Langmuir method on a subphase containing L-ascorbic and D-isoascorbic acids with a concentration of 10 -2, 10 -3 M at a temperature of 25, 37 and 41°C was studied. The influence of the isoforms of ascorbic acid, the composition and temperature of the subphase on the mechanical properties of monolayers (specific area, compressibility, collapse pressure) was experimentally found. It was marked that the introduction of ascorbic acid into the subphase leads to the displacement of compressibility isotherms to the region of large values of the specific area of the monolayer; a similar shift occurs with an increase of the concentration and temperature of the subphase. Numerical values of the main parameters of the 397 Изв. Сарат. ун-та. Нов. сер. Сер. Химия. Биология. Экология. 2018. Т. 18, вып. 4 monolayers for studied systems calculated in liquid-condensed and solid-crystalline states are presented. It is suggested that the adsorption of ascorbic acid on the subphase on the surface of the monolayer is due to the formation of hydrogen bonds. This study may be useful for understanding the processes of cell membrane modification under the influence of L- and D-isoforms of ascorbic acid: changes in the mobility of the components included in the membrane, its plasticity, stiffness, etc.