Biofilms are consortiums of individual microorganisms clustered together and attached to a surface. They are the defense mechanism many microorganisms employ to protect themselves against conditions threatening their survival. Surrounding the group of organisms is often a protective extracellular matrix composed of structural proteins, DNA, and other biological macromolecules. Common problems caused by biofilms include food contamination, infections, and pathogen virulence. Candida albicans is one problematic microorganism responsible for candidiasis, the most common fungal infection affecting humans. C. albicans is also responsible for a significant percentage of medical device infections, particularly those related to catheters, dentures, and pacemakers.

The purpose of this project is to combat biofilm growth by testing a novel way of inhibiting their structure and development through the use of iron oxide nanoparticles (NP). Previous research has indicated that other nanoparticles, such as those of silver, inhibit the growth of biofilms on various surfaces. By taking advantage of the magnetic properties of these nanoparticles, a more cost-effective method can be created to combat biofilm growth on catheters or tooth surfaces, possibly by developing a nanoparticle-infused surface suitable for use in or near the human body.

C. albicans were cultured in Sabouraud Dextrose Broth and once optimal density was reached, transferred to a well plate where they were allowed to adhere for 1.5 hours. For the experimental group, the iron oxide nanoparticles are placed on a magnetic plate during the adhesion phase. Wells were rinsed and broth was added to allow the maturation of the adhered fungal biofilm. Crystal violet staining was used as the primary method for biofilm quantification. Colorimetric spectrophotometry of the residue crystal violet solution was used to provide a relative approximation of how much biofilm remains in the presence of different treatments.

Results demonstrated that there was a statistically significant ~50% decrease in biofilm content for the treatment of iron oxide nanoparticles without magnetization. With magnetization, an additional ~25% decrease in biofilm content was observed. Testing of the stage at which the magnetization of the nanoparticles takes place indicated that magnetizing during the adherence phase of biofilm development provided the best reduction in biofilm content. This suggests that this method is best used as a preventative method for biofilm inhibition.

Future studies would be necessary to evaluate the concentrations of iron oxide NPs that would be effective at combatting biofilm growth and safe for proximity in or near the human body. Infusing or coating a medical device, like a catheter, with iron oxide nanoparticles could be a measure taken to prevent biofilm adherence and growth. The results of this experiment are promising for the development of future technologies that incorporate iron oxide nanoparticles as a method for combating C. albicans biofilm infections.