Anti-Bacterial Nanofibers

Contamination by microorganisms detrimentally impacts a wide-range of industries, including medicine, separations, and marine vessels. New materials or surface coatings, like electrospun nanofiber mats that can be engineered to delay or potentially prevent the attachment of microorganisms, are desperately needed.
Antibacterial surfaces disrupt bacterial cells, causing cell death. In general, antibacterial surfaces alter the architecture of platforms to reduce or possibly eliminate the adherence of microorganisms and the subsequent formation of biofilms. As a key aspect of modern medicine, antibacterial agents have greatly reduced the number of mortalities that result from bacterial infections. Unfortunately, globalization and a decline in antibiotic discovery correspond with the continued rise of antibiotic-resistant bacteria. Each year in the United States, antibiotic resistance directly results in 23,000 deaths, and it is predicted that 10 million deaths per year will occur worldwide by 2050. Although more deaths still occur worldwide because of lack of access to antibacterial agents than to antibiotic-resistant bacteria, the number of β-lactamases that have been identified since 1990 has increased ten-fold, thus demonstrating the increasing problems that are associated with antibiotic-resistant bacteria.
The fiber mats that are produced by electrospinning can easily be optimized during or after the fibers are produced for specific applications. Tailoring the release rate of antimicrobial agents from a nanofiber mat can be accomplished by changing the precursor solution, because the polymer matrix in which the agents are embedded is often largely responsible for the mat’s degradation. Alternatively, pharmaceuticals or active agents can be decorated on the exterior of the nanofibers. Implementing solution blending, coaxial electrospinning, or emulsion electrospinning allows for the encapsulation of active agents inside the fibers. Many different surface science techniques can be used to alter fabricated nanofiber mats, including electrostatically or covalently attaching functional moieties, dipping the produced mats into a polymer bath to apply a coating, or using self-assembly techniques.
For economic and functional reasons, electrospun nanofibers show great promise for use as antibacterial materials, because of their nano-effects, including their great surface energy, chemical reactivity, and reported conductivity (i.e., thermal and electrical). Nanofiber mats can be used as a conformal surface coating or as a free-standing material to provide a controlled interaction with microorganisms. Nanofiber mats can coat surfaces and impart their antibacterial properties to the underlying substrate. Because of their highly porous yet interconnected structure and high surface area, nanofibers are a great scaffold to deliver biocidal agents, able to protect wounds while administering desirable therapeutics.
Antibacterial surfaces are either bacteriostatic or bactericidal, often through an interference with bacterial DNA, protein synthesis, or the activity of enzymes that are involved with bacteria cell metabolism. Antibacterial surfaces kill bacteria by releasing drugs, direct contact with cell membranes, or expressing cationic polymers, Figure 1. Biocide-releasing antibacterial surfaces commonly use silver, triclosan, or chitosan because of their effects on both Gram-positive and Gram-negative bacteria. The challenges of using release biocides include the development of resistance, optimization of their release duration and kinetics, and maintenance of a high enough concentration to continually eliminate bacteria.

Figure 1. Antibacterial surfaces inactivate microorganisms by either releasing biocides, having mechano-bactericidal nanotopographies, or via immobilized cationic species.

FNM Co, Ltd., can produce different types of nanofiber coated substrates with antibacterial properties which are applicable in a wide range of applications especially for medical purposes according to the customers’ demands. The documents below show the antibacterial activity of some nanofiber layers (against Escherichia Coli and Staphylococcus Aureus) produced by FNM Co. Ltd.

Kurtz, Irene, and Jessica Schiffman. "Current and emerging approaches to engineer antibacterial and antifouling electrospun nanofibers." Materials 11, no. 7 (2018): 1059.