Bioploymer network engineering
Polymer physics of mucin secretion
Dynamics of marine biopolymers and their role in global carbon cycling
Our research program focuses on biopolymer networks. Regardless of their size, composition or origin, biopolymers can assemble forming networks that exhibit unique emerging properties playing significant roles in scales ranging from the cell to global element cycling. A broad range of intracellular events including storage and delivery of hormones in secretory cells or release of toxins in phytoplankton, or molecular shielding by intracellular chaperones are all carried out by biopolymer networks.
Networks are found forming the matrix of tissues and organs or performing critical functions like epithelial protection by mucus or joint lubrication by synovial fluid. At the other end of the dimensional scale marine biopolymers comprise one of the largest stocks of organic matter found in our planet. They can reversibly self-assemble forming microscopic gels, and their assembly-dispersion equilibrium plays a most critical role in global carbon cycling. The physical principles that govern polymer networks dynamics in the cell and those that govern the dynamics of association of marine biopolymers are virtually the same. They all result from low energy molecular interactions, a subject that lies at the interface of physics and biology. These broadly different areas of inquiry seem entirely unrelated but are in fact intimately associated by a common set of largely isomorphic physical principles that rule them all and that is the focus and main strength of our research program.
Our discoveries have been consistently published in high impact journals opening new ground and introducing novel ideas in a broad range of enquiry. Several of our contributions are now established paradigms in fields ranging from the biophysics of secretion to intracellular communications and to the geochemistry of polymer dynamics in the ocean. Our studies on mucus secretion led to the first demonstration that mucins, the large biopolymers that make the mucus gel, are stored forming a condensed network inside secretory granules, undergoing phase transition and hydration at the time of delivery to form the mucus hydrogel.
These observations essentially transformed previous ideas bringing a new paradigm of high predictive power to understanding airway physiology and the pathology of mucus. Ion exchange properties of polyelectrolytes present in the matrix of the endoplasmic reticulum of the cell in conjunction with K and Ca channels function as a remarkable ion oscillator that plays a fundamental role in intracellular communications. A similar scenario is taking place in oceanography where our observations are starting to have a significant impact in geochemistry. A spin-off from these findings is their application as models for engineering development of drug delivery, and vaccine preservation systems.
MD, State University of Chile, 1965
- Tam, P.Y. and P. Verdugo (1981). Control of mucus hydration as a Donnan equilibrium process. Nature 292:340-342.
- Verdugo, P. Goblet cells and mucus secretion. Ann. Rev. Physiology. 52: 157–176, 1990.
- Verdugo, P. Polymer gel phase transition in condensation-decondensation of secretory products. Adv. Pl. Sci. 110:145–156, 1993.
- Nguyen, T., W-C. Chin, and P. Verdugo. (1998) Role of Ca2+/K+ ion exchange in intracellular storage and release of Ca2+. Nature395:908-912
- Chin, W-C., M.V. Orellana, and P. Verdugo. (1998) Formation of microgels by spontaneous assembly of dissolved marine polymers. Nature391: 568-572
- Verdugo, P., Orellana, M.V., Chin, W-C., Petersen, T.W., van den Eng, G., Benner, R., Hedges, J.I. (2008) Marine biopolymer self-assembly: Implications for carbon cycling in the ocean. Faraday Discussion (The Royal Soc of Chemistry) 139: 393-398.
- Verdugo, P., Orellana M.V., & Freitag, C.(1995). The secretory granule as a biomimetic model for drug delivery. Proc. Int. Control Release Bioact. Mater. 25.