This blog post explores how the unique adhesive principle of mussels evolved into medical bioadhesives, fascinatingly tracing the journey of nature’s wisdom transforming into modern medical technology.
Have you ever warmed your frozen body with a steaming bowl of hot and spicy mussel soup on a cold winter day? The uniquely refreshing and invigorating taste of mussels is deeply familiar, whether enjoyed at a gathering or on the dinner table where Korean families gather. Beyond that, mussels appear frequently on Korean tables in diverse forms, from seafood spaghetti to fried mussels. But what if Koreans encountered mussels in the operating room, saving human lives? It might sound somewhat unfamiliar and strange, but in fact, medical bioadhesives using mussel protein have been developed for nearly a decade. Furthermore, the path to mass-producing this adhesive has been opened by Korean researchers, and active research for commercialization is currently underway. Let’s now explore how mussels were reborn as bioadhesives and what the underlying principle is.
The catalyst for mussels’ rebirth as medical adhesives lies in the concept of ‘biomimicry’. Biomimicry refers to a scientific approach that applies the operating principles found within natural objects to other technologies or subjects, seeking a link between the solutions nature has secured over long periods and the technical problems humans face. Today, numerous biomimetic applications exist around South Korea. Notable examples include Velcro, which mimics the hook structure of burdock seeds; the airplane invented by the Wright brothers after observing bird flight; and robotic vacuum cleaners utilizing the principle of how bats detect obstacles using ultrasound. Furthermore, the turtle ship devised by Admiral Yi Sun-sin during the Joseon Dynasty is another example where ideas were drawn from the structure and movement of specific animals, and can be broadly considered an instance of biomimetic technology. To biomimic mussel protein, scientists utilized the following unique characteristics of mussels.
To firmly attach to highly uneven rock surfaces, mussels produce a unique adhesive protein. One might expect a very thick protein structure to be necessary for mussels to remain securely attached to rocks in coastal environments with crashing waves and strong winds. However, the actual thickness of the adhesive protein is relatively thin, about 2mm. The astonishing fact is that a single strand of this adhesive protein can withstand a weight of up to approximately 12.5kg. Typically, a mussel extends about 10 strands of adhesive protein to anchor itself to a rock. Therefore, a single mussel theoretically possesses the strength to support an object weighing approximately 125kg.
The mussel adhesive protein is broadly divided into two parts: a thin, thread-like filament (Thread) and a plaque (Plaque) attached to its end. To date, three types of collagen and six types of fp (Foot Protein) have been identified in mussel adhesive proteins. The thread portion is primarily composed of collagen, responsible for strong tensile strength, while the plaque portion consists of proteins like fp-3 and fp-5, providing the powerful adhesive force that prevents the mussel from detaching from the rock. A key player in this process is DOPA (dihydroxyphenylalanine), an amino acid derivative. DOPA is a hydrophilic amino acid within the FP that plays a crucial role in forming the polymeric protein structure, enabling the mussel to adhere strongly even to smooth surfaces.
Leveraging these characteristics of mussel proteins, engineers have successfully developed high-adhesion bioadhesives that maintain their performance even underwater. The protein primarily used in medical mussel adhesives is fp-1, which retains its adhesive strength even in humid environments. To further enhance its effectiveness for medical applications, researchers irradiate the mussel-derived protein with blue-wavelength light. When blue light is applied, ‘dityrosine crosslinks’ form between the proteins. This structural change further stabilizes the protein’s molecular structure and significantly enhances its flexibility and viscosity.
The resulting medical bioadhesive exhibits very low human rejection, making it suitable for use as a cell and tissue adhesive. It is also environmentally friendly due to its natural biodegradability. Furthermore, animal testing results indicate that adhesives utilizing mussel extract protein demonstrated superior outcomes in terms of inflammatory response and tissue defects compared to conventional suturing methods or other adhesives like fibrin glue and cyanoacrylate. These results strongly suggest the potential for mussel-based adhesives to gain absolute dominance in the global medical suturing and bonding market. Considering the current global market size for this sector is estimated to be nearly 15 trillion won, the economic ripple effect this adhesive could have on the medical and industrial fields in the future is truly enormous.
The era of viewing mussels merely as a simple side dish is over. A single mussel in clear broth has transformed into a biomaterial capable of healing someone’s wounds. But is this transformation unique to mussels? Any natural material found around South Korea has ample potential for new metamorphosis through biomimetic technology. While creating entirely new methods is important, discovering the wisdom hidden within nature—evolved over billions of years—and applying it technologically to build a better life is also a crucial task for South Koreans navigating the 21st century.
