Mechanistic Studies of Unipolar Adhesive Polysaccharides

This project is a multidisciplinary collaboration to explore the mechanical properties of a potent adhesive biopolymer produced by bacteria and to determine how these properties are genetically and biochemically specified and modulated. The adhesive biological polymer plays an important role in bacteria biofilm formation, an early step in both beneficial and harmful bacterial interactions with other organisms and materials.

In addition, these types of biopolymers hold significant promise for development of biocompatible and water-tolerant adhesives. The proposed studies will provide a detailed mechanistic understanding of how these types of materials impart strong adhesion. The project combines expertise from microbiology, molecular genetics, biomechanics, chemistry, physics and mathematical modeling to address these questions.

The investigators will provide cross-disciplinary training and experience for participating graduate students in biology, chemistry and physics. In addition, the project includes a significant outreach component to local Bloomington grade schools and a local children’s science museum named the Wonderlab to develop activities that allow young students to independently experiment with and learn about adhesives at macro- and micro-scales.

The adhesive material under study is part of a growing family of polysaccharide-based products that concentrate at the poles of rod-shaped bacterial cells in the large and diverse Alphaproteobacteria class and often impart interactions with surfaces. This polar adhesion process is the first step in forming multicellular biofilms, and for host-associated bacteria is often an early step in symbiosis or pathogenesis.

With this project the investigators will use the plant pathogen Agrobacterium tumefaciens as an experimental platform to determine the genetic and biochemical processes which result in the adhesive properties of the material, by performing a battery of complimentary biomechanical analyses on a collection of mutants and regulated derivatives that affect adhesive production. Mathematical modeling using the experimental data generated will define the adhesion process, and an iterative cycle of experimentation and modeling will ensure development of a general mechanistic understanding for adhesion.

With the advances in understanding of adhesive synthesis and deposition, the investigators will identify key determinants that can be manipulated, with the long-term goal of engineering a customizable bioadhesive platform(s) for generating materials with different strengths and durability.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.