Research

In most part of the polymeric systems we work with we obtain either physical gels (non chemical reaction involved) or polymer matrices and networks known as hydrogels. These gels retain a considerable amount of water (swelling capacity) and allow drugs to be retained and released in a controlled way. Moreover, in some systems we are imposing a temperature control of the swelling capacity and the release from the gels. In this regard they become of outmost importance for biomedical applications, namely for transdermal drug purpose and we aim to evaluate the parameters that favor both the process of gelation and the release from these gels.

Another topic being covered is the characterization of self-assembled small (surfactants, quantum dots), and large (polymers, proteins, coacervates) particles, by determination of their size, shape, and interface electrical properties. In this regard we want to stress the studies with long hydrocarbon chain IL’s which act as a new class of surfactants with unique abilities -nano-droplets of “green fluids” dispersed in water or non-aqueous solvents. Due to this dual nature one can combine two reagents of completely different natures (hydrophilic and hydrophobic) into a macroscopically homogeneous solution, being micellar or microemulsion states.

Another extension of this work was recently initiated with biological materials, namely animal cells and virus-like particles where the degree of protein “coating” and the aggregation of the particles has been evaluated.

Other studies involve reactivity of chemicals on supramolecular (nano/micro) aggregates and distribution of species between soft interfaces and bulk solvents. In particular, we have being studying the pH definition near the colloid interfaces and the mechanisms of partition / permeation of chemicals and drugs through micelles, microemulsions and vesicles as mimetic systems of biological and environment systems. Additionally, we also explore the kinetics of incorporation / release of small chemicals and proteins from nano- and micro-particles.

Plant foliage it is another type of surface being studied although here we are more interested into chemical characterization. In this regard we have been characterizing flavonoids (polyphenols) expressed by some plant leaves (cork, coffee, beans) and their relation with the different types of stress -light, temperature, humidity. These studies run in parallel with biochemical characterization done by our collaborators. Moreover, some of the flavonoids present color in vivo although its color fade when extracted from the plants. This led us to explore the mechanisms of the color stabilization via colloid particle formation (hydrophobization of some flavonoids).