Use of magnetic nanoparticles as a drug delivery system to improve chlorhexidine antimicrobial activity

Grażyna Tokajuk,1,2 Katarzyna Niemirowicz,1 Piotr Deptuła,1,3 Ewelina Piktel,1 Mateusz Cieśluk,1 Agnieszka Z Wilczewska,4 Jan R Dąbrowski,3 Robert Bucki1 1Department of Microbiological and Nanobiomedical Engineering, Medical University of Białystok, 2Department of Intergrated Dentistry, Medical University of Białystok, 3Department of Materials and Biomedical Engineering, Białystok University of Technology, 4Institute of Chemistry, University of Białystok, Białystok, Poland Abstract: Nanotechnology offers new tools for developing therapies to prevent and treat oral infections, particularly biofilm-dependent disorders, such as dental plaques and endodontic and periodontal diseases. Chlorhexidine (CHX) is a well-characterized antiseptic agent used in dentistry with broad spectrum activity. However, its application is limited due to inactivation in body fluid and cytotoxicity toward human cells, particularly at high concentrations. To overcome these limitations, we synthesized nanosystems composed of aminosilane-coated magnetic nanoparticles functionalized with chlorhexidine (MNP@CHX). In the presence of human saliva, MNPs@CHX displayed significantly greater bactericidal and fungicidal activity against planktonic and biofilm-forming microorganisms than free CHX. In addition, CHX attached to MNPs has an increased ability to restrict the growth of mixed-species biofilms compared to free CHX. The observed depolarization of mitochondria in fungal cells treated with MNP@CHX suggests that induction of oxidative stress and oxidation of fungal structures may be a part of the mechanism responsible for pathogen killing. Nanoparticles functionalized by CHX did not affect host cell proliferation or their ability to release the proinflammatory cytokine, IL-8. The use of MNPs as a carrier of CHX has great potential for the development of antiseptic nanosystems. Keywords: chlorhexidine, magnetic nanoparticles, antimicrobial properties, anti-biofil

Magnetic nanoparticles enhance the anticancer activity of cathelicidin LL-37 peptide against colon cancer cells

Katarzyna Niemirowicz,1 Izabela Prokop,2 Agnieszka Z Wilczewska,3 Urszula Wnorowska,1 Ewelina Piktel,1 Marzena Wątek,4 Paul B Savage,5 Robert Bucki1,6 1Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, 2Department of Medicinal Chemistry, Medical University of Bialystok, 3Institute of Chemistry, University of Bialystok, Bialystok, 4Department of Hematology, Holy Cross Oncology Center of Kielce, Kielce, Poland; 5Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA; 6Department of Physiology, Pathophysiology and Microbiology of Infections, The Faculty of Health Sciences of the Jan Kochanowski University in Kielce, Kielce, Poland Abstract: The pleiotropic activity of human cathelicidin LL-37 peptide includes an ability to suppress development of colon cancer cells. We hypothesized that the anticancer activity of LL-37 would improve when attached to the surface of magnetic nanoparticles (MNPs). Using colon cancer culture (DLD-1 cells and HT-29 cells), we evaluated the effects of MNPs, LL-37 peptide, its synthetic analog ceragenin CSA-13, and two novel nanosystems, ie, MNP@LL-37 and MNP@CSA-13, on cancer cell viability and apoptosis. Treatment of cancer cells with the LL-37 peptide linked to MNPs (MNP@LL-37) caused a greater decrease in cell viability and a higher rate of apoptosis compared with treatment using free LL-37 peptide. Additionally, we observed a strong ability of ceragenin CSA-13 and MNP@CSA-13 to induce apoptosis of DLD-1 cells. We found that both nanosystems were successfully internalized by HT-29 cells, and cathelicidin LL-37 and ceragenin CSA-13 might play a key role as novel homing molecules. These results indicate that the previously described anticancer activity of LL-37 peptide against colon cancer cells might be significantly improved using a theranostic approach. Keywords: anticancer activity, colorectal cancer, ceragenin, cathelicidin LL-37, magnetic nanoparticle

Gold-functionalized magnetic nanoparticles restrict growth of Pseudomonas aeruginosa

Katarzyna Niemirowicz,1,2 Izabela Swiecicka,3 Agnieszka Z Wilczewska,4 Iwona Misztalewska,4 Beata Kalska-Szostko,4 Kamil Bienias,2 Robert Bucki,1,5,6 Halina Car21Department of Microbiological and Nanobiomedical Engineering, 2Department of Experimental Pharmacology, Medical University of Bialystok, 3Department of Microbiology, 4Institute of Chemistry, University of Bialystok, Bialystok, 5Faculty of Health Sciences, Jan Kochanowski University, Kielce, Poland; 6Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USAAbstract: Superparamagnetic iron oxide nanoparticles (SPIONs) and their derivatives (aminosilane and gold-coated) have been widely investigated in numerous medical applications, including their potential to act as antibacterial drug carriers that may penetrate into bacteria cells and biofilm mass. Pseudomonas aeruginosa is a frequent cause of infection in hospitalized patients, and significant numbers of currently isolated clinical strains are resistant to standard antibiotic therapy. Here we describe the impact of three types of SPIONs on the growth of P. aeruginosa during long-term bacterial culture. Their size, structure, and physicochemical properties were determined using transmission electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. We observed significant inhibition of P. aeruginosa growth in bacterial cultures continued over 96 hours in the presence of gold-functionalized nanoparticles (Fe3O4@Au). At the 48-hour time point, growth of P. aeruginosa, as assessed by the number of colonies grown from treated samples, showed the highest inhibition (decreased by 40%). These data provide strong evidence that Fe3O4@Au can dramatically reduce growth of P. aeruginosa and provide a platform for further study of the antibacterial activity of this nanomaterial.Keywords: antibacterial activity, Pseudomonas aeruginosa, superparamagnetic nanoparticles, iron oxides, gold-coated nanoparticle

Core–shell magnetic nanoparticles display synergistic antibacterial effects against Pseudomonas aeruginosa and Staphylococcus aureus when combined with cathelicidin LL-37 or selected ceragenins

Katarzyna Niemirowicz,1 Ewelina Piktel,1 Agnieszka Z Wilczewska,2 Karolina H Markiewicz,2 Bonita Durnaś,3 Marzena Wątek,4 Irena Puszkarz,3 Marta Wróblewska,5,6 Wieslawa Niklińska,7 Paul B Savage,8 Robert Bucki1,3 1Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, 2Institute of Chemistry, University of Bialystok, Bialystok, 3Department of Physiology, Pathophysiology and Immunology of Infections, The Faculty of Health Sciences of the Jan Kochanowski University in Kielce, 4Holy Cross Oncology Center of Kielce, Kielce, 5Department of Dental Microbiology, Medical University of Warsaw, 6Department of Microbiology, Central Clinical Hospital in Warsaw, Warsaw, 7Department of Histology and Embryology, Medical University of Bialystok, Bialystok, Poland; 8Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA Abstract: Core–shell magnetic nanoparticles (MNPs) are promising candidates in the development of new treatment methods against infections, including those caused by antibiotic-resistant pathogens. In this study, the bactericidal activity of human antibacterial peptide cathelicidin LL-37, synthetic ceragenins CSA-13 and CSA-131, and classical antibiotics vancomycin and colistin, against methicillin-resistant Staphylococcus aureus Xen 30 and Pseudomonas aeruginosa Xen 5, was assessed alone and in combination with core–shell MNPs. Fractional inhibitory concentration index and fractional bactericidal concentration index were determined by microdilution methods. The potential of combined therapy using nanomaterials and selected antibiotics was confirmed using chemiluminescence measurements. Additionally, the ability of tested agents to prevent bacterial biofilm formation was evaluated using crystal violet staining. In most conditions, synergistic or additive effects were observed when combinations of core–shell MNPs with ceragenins or classical antibiotics were used. Our study revealed that a mixture of membrane-active agents such as LL-37 peptide or ceragenin CSA-13 with MNPs potentialized their antibacterial properties and might be considered as a method of delaying and overcoming bacterial drug resistance. Keywords: synergistic activity, antibiotic-resistant bacteria, LL-37 peptide, ceragenins, magnetic nanoparticle