Autopoietic Behavior of Dynamic Covalent Amphiphiles

Abstract

The condensation of aldehydes and amines in water to give amphiphilic imines can lead to a particular autocatalytic behavior known as autopoiesis, in which the closed micellar structure made by the amphiphile at the mesoscale can accelerate the condensation of its constituents. Herein, through a combination of analytical tools, including diffusion ordered spectroscopy (DOSY) as well as light, neutron, and X-ray scattering techniques, the thermodynamic and kinetic parameters were probed at both the level of dynamic covalent imine bond formation and the level of the resulting micellar self-assemblies. It was found that the autopoietic behavior was the result of a combination of several parameters, including solubilization of hydrophobic building blocks, template effect at the core-shell interface, and growth/division cycles of the micellar objects.

Design of Stimuli‐Responsive Dynamic Covalent Delivery Systems for Volatile Compounds (Part 1): Controlled Hydrolysis of Micellar Amphiphilic Imines in Water

“…At this moment, the concentration of imine is 5 mM, and the increase in size corresponds to the entrapment of the released hydrophobic aldehyde in the remaining micellar imine structures, as described in our previous studies. [46,48,49] In addition, after 3 h, another population of larger objects (R h > 100 nm) appeared with a rapidly increasing size of 0.65 nm min À 1 , and this microemulsion continued to grow after the disappearance of the small micelle population, leading to a turbid solution and eventually to a macroscopic phase separation (Figure 4c). From these preliminary results using our reference imine A2, we tried to explore the possibility of stabilizing the micellar structure by introducing hydrogen bonding units into the imine surfactants.…”

“…Such supramolecular structures can affect the stability of the imine bond by protecting it from water when it is integrated in the hydrophobic micellar core. [49] 1 H NMR spectra and by plotting the imine concentration as a function of time following Equation (1):…”

“…[24,43,45] Recently, we and others observed the possibility of influencing the equilibrium and kinetic constants of imine formation when imines are partially protected from water in amphiphilic micellar structures. [46][47][48][49] In particular, it has been shown that the use of imine-based surfactants can lead to i) their autocatalytic condensation in a process related to autopoiesis [48][49][50] and to ii) their modular and controllable recombination in various types of dynamic micellar and vesicular structures. [51][52][53][54][55][56][57][58] Among a number of industrially relevant applications, amphiphilic structures are commonly used to solubilize hydrophobic volatile compounds, such as fragrances, in aqueous formulations of almost all perfumed body care or household products.…”

Design of Stimuli‐Responsive Dynamic Covalent Delivery Systems for Volatile Compounds (Part 2): Fragrance‐Releasing Cleavable Surfactants in Functional Perfumery Applications

“…In our previous work, we have built dynamic imines connecting hydrophobic and hydrophilic moieties in order to generate dynamic covalent amphiphiles, which can protect their imine bonds from fast hydrolysis in water because of their self-assembly in various micellar structures. [14][15][16] In particular, in the preceding paper, [17] we showed that amphiphilic imines (e. g. 1-4, Scheme 1), obtained by condensation of a fragrance aldehyde as the hydrophobic part with an amine derived from a poly(propylene oxide) and poly(ethylene oxide) diblock copolymer of variable length (such as Jeffamines® M1000 and M2070) as the hydrophilic section have surfactant properties and self-assemble into micellar structures in water. We furthermore demonstrated that placing the hydrolytically labile imine group within the hydrophobic part of the micelle, for example by using a linker between the labile imine group and the hydrophilic part of the amphiphile, resulted in relatively stable structures.…”

Molecules, Information and the Origin of Life: What Is Next?

“…Some researchers addressed this puzzling issue, without a true, encouraging success, yet. Maturana's pioneering work on the concept of "autopoiesis" [21][22][23], which can be retrieved in very recent papers [22][23][24][25], introduced intriguing insights about how life is "auto-representing". Maturana, however, stands on a plain philosophical ground.…”