Dong Soo Hwang

Mussel foot proteins (mfps) have been investigated as a source of inspiration for the design of underwater coatings and adhesives. Recent analysis of various mfps by a surface forces apparatus (SFA) revealed that mfp-1 functions as a coating, whereas mfp-3 and mfp-5 resemble adhesive primers on mica surfaces. To further refine and elaborate the surface properties of mfps, the force-distance profiles of the interactions between thin mfp (i.e. mfp-1, mfp-3 or mfp-5) films and four different surfac

The adhesive plaques of Mytilus byssus are investigated increasingly to determine the molecular requirements for wet adhesion. Mfp-2 is the most abundant protein in the plaques, but little is known about its function. Analysis of Mfp-2 films using the surface forces apparatus detected no interaction between films or between a film and bare mica; however, addition of Ca(2+) and Fe(3+) induced significant reversible bridging (work of adhesion W(ad) approximately 0.3 mJ/m(2) to 2.2 mJ/m(2)) between

The chemistry of mussel adhesion has commanded the focus of much recent research activity on wet adhesion. By comparison, the equally critical adhesive processing by marine organisms has been little examined. Using a mussel-inspired coacervate formed by mixing a recombinant mussel adhesive protein (fp-151-RGD) with hyaluronic acid (HA), we have examined the nanostructure, viscosity, friction, and interfacial energy of fluid-fluid phase-separated coacervates using the surface forces apparatus and

Mussel-inspired self-polymerized catecholamine coatings have been widely utilized as a versatile coating strategy that can be applied to a variety of substrates. For the first time, nanomechanical measurements and an evaluation of the contribution of primary amine groups to poly(catecholamine) coatings have been conducted using a surface-forces apparatus. The adhesive strength between the poly(catecholamine) layers is 30-times higher than that of a poly(catechol) coating. The origin of the stron

The first direct probing of the nanomechanics of cation–π interactions in aqueous media was accomplished by using a surface forces apparatus with complementary theoretical simulations. The tetraethylammonium (TEA) ion breaks the adhesion between poly-L-tryptophan (PTrp) and poly-L-lysine (PLL) with a 100 times higher sensitivity relative to the K+ ion (PS=polystyrene, PTyr=poly-L-tyrosine, and ACh=acetylcholine). As a service to our authors and readers, this journal provides supporting informati

Complex coacervation driven liquid-liquid phase separation (LLPS) of biopolymers has been attracting attention as a novel phase in living cells. Studies of LLPS in this context are typically of proteins harboring chemical and structural complexity, leaving unclear which properties are fundamental to complex coacervation versus protein-specific. This study focuses on the role of polyethylene glycol (PEG)-a widely used molecular crowder-in LLPS. Significantly, entropy-driven LLPS is recapitulated

Mussel adhesive proteins have been suggested as a basis for environmentally friendly adhesives for use in aqueous conditions and in medicine. However, attempts to produce functional and economical recombinant mussel adhesive proteins (mainly foot protein type 1) in several systems have failed. Here, the cDNA coding for Mytilus galloprovincialis foot protein type 5 (Mgfp-5) was isolated for the first time. Using this cDNA, we produced a recombinant Mgfp-5 fused with a hexahistidine affinity ligan

Si-based anodes in lithium ion batteries (LIBs) have exceptionally high theoretical capacity, but the use of a Si-based anode in LIBs is problematic because the charging-discharging process can fracture the Si particles. Alginate and its derivatives show promise as Si particle binders in the anode. We show that calcium-mediated "egg-box" electrostatic cross-linking of alginate improves toughness, resilience, electrolyte desolvation of the alginate binder as a Si-binder for LIBs. Consequently, th

The holdfast or byssus of Asian green mussels, Perna viridis, contains a foot protein, pvfp-1, that differs in two respects from all other known adhesive mussel foot proteins (mfp): (1) instead of the hallmark L-3,4-dihydroxyphenylalanine (DOPA) residues in mfp-1, for example, pvfp-1 contains C(2)-mannosyl-7-hydroxytryptophan (Man7OHTrp). (2) In addition, pvfp-1 chains are not monomeric like mfp-1 but trimerized by collagen and coiled-coil domains near the carboxy terminus after a typical domain

Here we report the possible contribution of cation-π interaction to underwater adhesion of mussels by using DOPA-deficient recombinant mussel adhesive proteins. Considering the instability of DOPA in an oxidative environment, the cation-π interaction in DOPA-deficient biopolymers provides a complementary cross-linking mechanism for the design of novel underwater adhesives.

Eine erste direkte Untersuchung der Nanomechanik von Kation-π-Wechselwirkungen in wässrigem Medium wurde mit einem Oberflächenkraftmessgerät durchgeführt und durch theoretische Simulationen ergänzt. Das Tetraethylammonium-Ion (TEA) verhindert die Adhäsion von Polytryptophan (PTrp) und Poly-L-lysin (PLL) mit einer 100-fach höheren Empfindlichkeit als das K+-Ion (PS=Polystyrol, PTyr=Poly-L-tyrosin, ACh=Acetylcholin). As a service to our authors and readers, this journal provides supporting informa