NEWS | Shark-Inspired Surfaces: A Biomimetic Strategy for Preventing Hospital-Acquired Infections

Hospital-acquired infections (HAIs) contribute to tens of thousands of deaths annually in the United States (Bhandari). These HAIs are caused by bacterial, viral, and fungal pathogens, some of which have developed high levels of resistance due to the widespread use of antibiotics in hospital settings (Cleveland Clinic). These infections not only pose a serious threat to patients, but also further spread these deadly pathogens. However, a promising new solution has emerged: shark skin. Covered in microscopic diamond-like textures, shark skin naturally resists the growth and attachment of microorganisms (National Library of Medicine and Sharklet Technologies). By using biomimicry to replicate these patterns on hospital surfaces, the spread of HAIs could be greatly reduced.

Despite advances in medicine, hospital-acquired infections remain a major concern for healthcare facilities worldwide. When bacteria are exposed to antibiotics, the weakest ones die, but the strongest ones survive and multiply (Cleveland Clinic). Repeated exposure to antibiotics can allow resistant strains to survive and reproduce, leading to the spread of antibiotic resistance (Cleveland Clinic). These bacteria, also known as superbugs, can contaminate hospital floors and other frequently touched areas (Fekadu and Getachewu). They can also enter the body through catheters and ventilators, and can even lie dormant and reawaken when stimulated by medical procedures (Tengsupakul). Superbugs can cause pneumonia, urinary tract infections, bloodstream infections, and surgical site infections (Tobin and Zahra). Some of these infections can have mortality rates approaching 50%, particularly when they spread to the bloodstream (Cleveland Clinic). With millions of patients acquiring HAIs annually (Tobin and Zahra), this is a serious issue. To tackle this and develop new methods of infection prevention, scientists have turned to sharks for inspiration.

The microscopic structure of shark skin is covered in dermal denticles, which are tiny, tooth-like scales that cover the skin of sharks (Gabler-Smith et al.). These precise patterns serve an important hydrodynamic function, helping sharks move efficiently through water by reducing drag (Gabler-Smith et al.). They also have another important function: their ability to deter bacteria (National Library of Medicine and Sharklet Technologies). It is important to note that bacteria must attach to surfaces before forming colonies and spreading (Hsu et al.). But the microscopic ridges and diamond patterns of sharks’ denticles prevent microorganisms from establishing a grip on sharks (National Library of Medicine and Sharklet Technologies). Shark skin does not kill bacteria; it reduces their ability to settle. By using biomimicry, which is the practice of solving human problems by copying the designs found in nature, this discovery has proven useful when tackling superbugs and other pathogens in hospitals (Reddy et al.).

Researchers have been able to replicate the microscopic pattern of dermal denticles by creating specially engineered surfaces with similar ridges and textures (Sharklet Technologies). Sharklet Technologies is an example of this. Sharklet Technologies is a biotechnology company that has developed surface technology to inhibit bacterial growth by mimicking the dermal denticles of sharkskin (Sharklet Technologies). This greatly reduces infection risk by physically preventing microorganisms from attaching and forming colonies. Dr. Anthony Brennan, the founder of Sharklet Technologies, was inspired by sharks' ability to prevent bacteria and created the antibacterial Sharklet Surface. The Sharklet surface consists of millions of tiny, raised diamond-shaped features, each measuring about 16 to 26 microns across (Sharklet Technologies). To put it into perspective, a single strand of human hair is 50 to 100 microns wide. The Sharklet surface relies on physical micro-patterning rather than antimicrobial chemicals, reducing the need for antimicrobial chemicals that can contribute to antibiotic resistance (Sharklet Technologies). It has been lab tested and demonstrated reductions in microorganisms such as MRSA, influenza, coronavirus, and fungi (Sharklet Technologies). Studies have shown that it hosts 94% fewer MRSA bacteria than traditional smooth surfaces (Reddy et al.). 

This technology has already been implemented and has succeeded in several medical applications. An example of this is its role in urinary catheters. Urinary catheters are one of the medical devices responsible for HAIs, specifically causing UTIs. Sharklet Technologies received its Small Business Innovation Research (SBIR) grant from the National Institute of Diabetes and Digestive and Kidney Diseases for a urinary catheter in 2013. Laboratory studies have shown that Sharklet significantly reduces the migration and colonization of E. coli on urinary catheters, greatly reducing the risk for infection (Reddy et al.). Recently, Sharklet has introduced Nitrile medical gloves for hospitals with the same pattern (Sharklet Technologies). These gloves have been proven to inhibit Staphylococcus aureus by 96.7% and E. coli by 91.8% (Sharklet Technologies). Sharklet Surfaces have also been used on central venous catheters, hospital surfaces, ceramic glove molds, intraocular lenses, and other medical applications (Sharklet Technologies). 

Despite promising results, shark skin-inspired surfaces are not a perfect solution to the problem of HAIs. One challenge is the limitation of where this technology can be used. These micro-nano fabrication processes are most suitable for flat, smooth surfaces (Sharklet Technologies). Creating the same microscopic diamond-shaped ridges on complex, curved, or multi-dimensional medical devices is extremely difficult and costly. Additionally, debris and residue, which are common in a hospital, can fill the microscopic spaces between the diamond-shaped ridges, allowing bacteria to attach and grow. However, when looking at the data and lab results surrounding shark skin-inspired surfaces, they prove to be a promising tool that could work alongside existing prevention strategies.

Hospital-acquired infections continue to pose a significant challenge to modern healthcare. By studying the microscopic structure of shark skin, researchers have been able to develop a new way to tackle superbugs and reduce bacterial attachment through biomimicry. This discovery has been shown to be effective in reducing risk for infections and making hospital environments safer. As scientists continue to explore the natural world, innovations inspired by living organisms may play an increasingly important role in shaping the future of medicine and technology.