Revestimento híbrido baseado em nanopartículas de prata para dispositivos médicos hospitalares

Abstract

Several processes can be used to guarantee the safety in the use of hospital medical devices, which can be reprocessed with the aim of avoiding nosocomial infections caused by cross-contamination or the accumulation of biofilm. Coatings based on hybrid materials containing metallic nanoparticles can be produced as a method for preventing infections as they have antimicrobial and/or antifouling properties. Therefore, the present work aimed to produce and physically-chemically characterize hybrid materials of the ureasil-polyether (u-PEO) type containing silver nanoparticles (AgNP) for future application as antimicrobial coating for hospital medical devices. To this end, AgNP were initially synthesized and specified using UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), zeta potential (PZ), in addition to requests for stability and microbiological broth microdilution tests to determine the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC) and the minimum fungicidal concentration (MFC). Hybrid precursors of the u-PEO 500 type were synthesized and gave rise to hybrid materials of the u-PEO 500 type. These materials incorporated AgNP and were characterized by FTIR, X-ray diffractometry (XRD), thermogravimetry (TG) and differential thermal analysis (DTA), contact angle and swelling. Furthermore, microbiological tests were applied to evaluate the antimicrobial action of the coating material. The results obtained revealed that the synthesized AgNP was dark gray in color, with the formation of an absorption band at λmax= 418 nm. FTIR indicated AgNP formed by the silver nitrate-sodium citrate complex. NTA indicated the spherical morphology of the NP, with an average size of 69.6 ± 1.5 nm and concentration of 1.98 x 109 ± 6.69 x 107 particles/mL. DLS analyzes showed mean hydrodynamic diameter (d.nm) = 101.06 nm and polydispersity index (IPD) = 0.312. The PZ value was -4.13 mV. Preliminary stability studies obtained NP resulted for up to 9 days. The MIC evaluation found bacteriostatic action against S. aureus ATCC, E. coli ATCC and C. albicans ATCC at concentrations ≥ 9.90 x 108 particles/mL, ≥ 1.24 x 108 particles/mL and ≥ 4.95 x 108 particles/mL, respectively. For MBC and MFC the results were ≥ 2.48 x 108 particles/mL and ≥ 9.90 x 108 particles/mL for E. coli ATCC and C. albicans ATCC, respectively. The u-PEO 500 hybrid materials produced a translucent and uniform visual appearance, FTIR confirmed the formation of the precursor and the absence of interactions between the components of the hybrid. XRD data confirmed the maintenance of the amorphous characteristics of the u-PEO 500 hybrid after the incorporation of AgNP. TG verified the thermal stability of the u-PEO hybrid material with AgNP and DTA revealed the endothermic behavior and absence of peak. The average contact angle of the u-PEO 500 and u-PEO 500:AgNP hybrid materials were 59,132 º ± 7,155 º and 53,734 º ± 1,263 º, respectively. The swelling test revealed an average percentage of liquid absorption of 63.45% ± 0.00571% and 64.36% ± 0.00471% for u-PEO 500 and u-PEO 500:AgNP, respectively. The antimicrobial activity of the hybrid material revealed the sensitivity of S. aureus ATCC to u-PEO:AgNP. However, E. coli ATCC and C. albicans ATCC were classified as resistant to the hybrid material tested. Pointing out, the work produced AgNP, monodisperse, with colloidal size, lasting for 9 days and with antimicrobial activity. The materials were produced using a ureasil-polyether hybrid base that completely incorporated the synthesized AgNP, without altering the physicochemical characteristics of the hybrid. Furthermore, the u-PEO 500:AgNP matrix exhibited antimicrobial activity against S. aureus ATCC, being a candidate for use in coatings for medical devices that can be reprocessed. Future studies are necessary to make it possible to increase the concentration of AgNP, without compromising the polymeric matrix, thus allowing an improvement in the antimicrobial profile of u-PEO 500:AgNP.