There is a vast amount of morphological, behavioral, and functional variation in biological adhesion systems, and I am generally interested in how various morphologies and behaviors are related to the performance and function of these systems. I am applying this framework to my Ph.D. research investigating lizard subdigital adhesive pads.
Functional Ecomorphology of the Adhesive Setae of Anolis Lizards
Gekkonid and Anolis lizards have independently evolved fibrillar adhesive structures, but the morphology of these structures are quite different for these taxa. Anoles have single fibers (setae) equipped with one triangular-shaped contact point (spatula), while geckos have branched, hierarchical setae terminating in hundreds to thousands of smaller triangular-shaped spatulae. Setal morphology varies predictably along the subdigital pad in a number of gecko species, and this variation likely has a number of functional implications that have not been empirically validated. Whether setal field configuration in Anolis lizards also varies along the subdigital pad has yet to be determined.
Caribbean Anolis lizards are well-known for the convergence of morphological phenotypes based on habitat use (the concept of ecomorphology or ‘ecomorphs’), yet it is unclear whether subdigital microstructure also varies in this way and if that variation has consequences for adhesive/locomotor performance in ecologically-relevant conditions. I plan to investigate the functional ecomorphology of anoline adhesive setae using a suite of morphological assays (scanning electron microscopy, microCT) and performance measures (adhesive and locomotor performance).
The Impacts of Surface Roughness on Gecko Adhesion
The natural substrates utilized by adhesive pad-bearing lizards are heterogeneous, complex, and vary in surface roughness over several orders of magnitudes (from the atomistic to meter scale). Surface metrologists and others theoreticians have demonstrated that characterizing surface roughness across all relevant length scales is no trivial task and attempting to understand how surface roughness impacts macroscopic properties like adhesion, wetting, and friction is even more daunting. While complex theoretical models are in the works for relatively simple elastomeric systems, there are no tractable models for understanding fibrillar adhesion on rough surfaces. Therefore, I am interested in measuring gecko adhesive performance on a variety of rough surfaces in the hopes of extracting information that can inform future theoretical models of fibrillar adhesion. Additionally, I am interested in how or if adhesive performance is related to the behavioral choices that adhesive pad-bearing lizards make in their natural habitat. I plan to investigate these topics utilizing both micro-scale (e.g., atomic force microscopy, optical profilometry) and macro-scale measurements (e.g., adhesive and locomotor performance, behavioral assays) in both laboratory and ecologically relevant conditions.
Beyond researching these themes in a biological context, I am also interested in informing and improving the design of synthetic adhesives based on these natural systems (i.e., through biomimetics). Current lizard-inspired synthetic adhesives are not capable of replicating all of the multifunctional properties of the biological adhesive systems, thus better understanding of the form and function of these biological systems is necessary to inform the design of the synthetic simulacra. I am interested in implementing knowledge gained from my morphological investigations into synthetic adhesives to better understand the relationships between form and function in the natural and synthetic systems.
I also have an interest in improving the process of biomimetics and consulting with industry or other investigators to integrate biomimetics into their R&D or research programs.