The Adhesion Mechanism of Marine Mussel Foot Protein: Adsorption of L-Dopa onα- and β-Cristobalite Silica Using Density Functional Theory

Shabeer Ahmad Mian,Younas Khan

doi:10.1155/2017/8756519

Abstract

Marine mussels strongly adhere to various surfaces and endure their attachment under a variety of conditions. In order to understand the basic mechanism involved, we study the adsorption of L-dopa molecule on hydrophilic geminal and terminal isolated silanols of silica (001) surface. High content of modified amino acid L-dopa is found in the glue-like material secreted by the mussels through which it sticks to various surfaces under water. To understand the adsorption behavior, we have made use of periodic Density Functional Theory (DFT) study. The L-dopa molecule adheres to silica surfaces terminated with geminal and terminal silanols via its catechol part. In both cases, the adhesion is achieved through the formation of 4 H-bonds. A binding energy of 29.48 and 31.67 kcal/mol has been estimated, after the inclusion of dispersion energy, for geminal and terminal silanols of silica, respectively. These results suggest a relatively stronger adhesion of dopa molecule for surface with terminal isolated silanols.

Highlights

Mussels are marine organisms that have the ability to attach themselves firmly to a variety of surfaces including glass, plastic, and metal oxides [1]
Mussels are marine organisms that stick to a variety of surfaces under turbulent conditions. This strong adhesion is achieved through the secretion of a glue-like material called byssus
It is believed that the catecholic ring of the dopa molecule interacts with the surface to achieve adhesion

Summary

Introduction

Mussels are marine organisms that have the ability to attach themselves firmly to a variety of surfaces including glass, plastic, and metal oxides [1] Their adhesion is so strong that they can even stick to nonstick materials such as Teflon [2]. The byssus is a bundle of threadlike materials that spreads out in a radially outward direction It consists of four parts, namely, plaque, thread, stem, and root [7]. Researchers have recently reported injectable synthetic polymers inspired by mussel adhesives These citrate-based adhesives are low-cost, nontoxic, and nonallergic [23]. In this study we will simulate the adsorption behavior of L-dopa molecule on hydroxylated, hydrophilic surfaces of silica having terminal isolated and geminal silanols. The present silica has a silanol density of 8.1 per nm which covers the silanols density of amorphous silica with a value of 5 hydroxyls per nm

Computational Method

Results and Discussion

Conclusion