Preparations of Silver/Montmorillonite Biocomposite Multilayers and Their Antifungal Activity

Abstract

In this study, the results about the influence of the surface morphology of layers based on montmorillonite (MMT) and silver (Ag) on antimicrobial properties are reported. The coating depositions were performed in the plasma of a radio frequency (RF) magnetron sputtering discharge. The studied layers were single montmorillonite layers (MMT) and silver/montmorillonite multilayers (MMT-Ag) obtained by magnetron sputtering technique with a different surface thickness. The resultant MMT-Ag biocomposite multilayers exhibited a uniform distribution of constituent elements and enhanced antimicrobial properties against fungal biofilm development. Glow-discharge optical emission spectroscopy (GDOES) analysis revealed the formation of MMT-Ag biocomposite multilayers following the deposit of a silver layer for an MMT layer that was initially deposited on a Si substrate. The surface morphology and thickness evaluation of deposited biocomposite layers were performed by scanning electron microscopy (SEM). A qualitative analysis of the chemical composition of thin layers was performed and the elements O, Ag, Mg, Fe, Al, and Si were identified in the MMT-Ag biocomposite multilayers. The in vitro antifungal assay proved that the inhibitory effect against the growth of Candida albicans ATCC 101231 CFU was more emphasized in the case of MMT-Ag biocomposite multilayers that in the case of the MMT layer. Cytotoxicity studies performed on HeLa cells showed that the tested layers did not show significant toxicity at the time intervals during which the assay was performed. On the other hand, it was observed that the MMT layers exhibited slightly higher biocompatible properties than the MMT-Ag composite layers.

Chitosan–Hydroxyapatite Composite Layers Generated in Radio Frequency Magnetron Sputtering Discharge: From Plasma to Structural and Morphological Analysis of Layers

“…In our previous works, we showed that at low radio frequency (rf) working powers, in magnetron sputtering plasma discharges, bioceramic multicomponent coatings for biomedical applications can be synthetized [ 10 , 11 , 12 ]. In [ 10 ], we showed that in rf magnetron discharge at about 1.2 × 10 −2 mbarr and 50 W rf power, after 4 h deposition time, regular granular-like structures on the surface of calcium phosphate layers deposited on Ti substrates can be generated.…”

A Refined Theory for Characterizing Adhesion of Elastic Coatings on Rigid Substrates Based on Pressurized Blister Test Methods: Closed-Form Solution and Energy Release Rate

“…Expressions of b i : 0 (νb 0 −b 0 −1) 9 [(246400ν 14 + 1821120ν 13 − 8460480ν 12 − 12906880ν 11 +93515520ν 10 − 81950400ν 9 − 236792640ν 8 + 611976960ν 7 − 492589440ν 6 − 49147840ν 5 +376824000ν 4 − 280452480ν 3 + 85227520ν 2 − 5839680ν − 1471680)b 14 0 + (−2217600ν 13 −18607680ν 12 + 57536640ν 11 + 173698560ν 10 − 667941120ν 9 + 69612480ν 8 + 2200746240ν 7 −3307046400ν 6 + 1126258560ν 5 + 1568589120ν 4 − 1822826880ν 3 + 701245440ν 2 − 65802240ν −13245120)b 13 0 + (9651664ν 12 + 72896448ν 11 − 71144160ν 10 − 1119267776ν 9 + 2334557488ν 8 +1241451904ν 7 − 7695302720ν 6 + 6999898240ν 5 + 694820656ν 4 − 4653734208ν 3 +2633550112ν 2 − 412307648ν − 35070000)b 12 0 + (−20168192ν 11 − 188320000ν 10 − 269349632ν 9 +3675105280ν 8 − 4655667200ν 7 − 5325813248ν 6 + 14630393344ν 5 − 7433028608ν 4 −4361576960ν 3 + 5412468480ν 2 − 1487153920ν + 23110656)b 11 0 + (27832816ν 10 + 263480608ν 9 +1578408496ν 8 − 7878679680ν 7 + 5949022688ν 6 + 10909049536ν 5 − 17558841888ν 4 +4055022464ν 3 + 5381205040ν 2 − 3057657568ν + 331157488)b 10 0 + (−25001856ν 9 −160093280ν 8 − 3755607488ν 7 +11562032960ν 6 − 4672981696ν 5 − 14016774784ν 4 +14067898560ν 3 − 553288512ν 2 − 3242293440ν + 796109536)b 9 0 + (14223264ν 8 − 177285456ν 7 +5772680176ν 6 − 12292371344ν 5 + 1847905136ν 4 + 11989787152ν 3 − 7398538288ν 2 −610917680ν + 854517040)b 8 0 + (−4537016ν 7 + 541371400ν 6 − 6112123192ν 5 + 9363854984ν 4 +258573976ν 3 − 6649831976ν 2 + 2412668760ν + 190023064)b 7 0 + (2461976ν 6 − 676309972ν 5 +4625467524ν 4 − 5212862504ν 3 − 553817344ν 2 + 2307859708ν − 492799388)b 6 0 + (−4740824ν 5 +527632460ν 4 − 2460623128ν 3…”

“…Coating technology is indispensable in many applications fields [1][2][3][4][5]. A film/substrate system usually consists of a substrate and its thin coating film, where the substrate could be a rigid substrate or a soft substrate, while the coating film is usually formed by chemical synthesis methods or physical deposition techniques and is usually polymer thin films, also including some polymer-based composite coatings with specific properties such as high adherence, crystallinity, temperature and corrosion resistance, or high conductivity [6,7]. The integrity and reliability of film/substrate systems obviously depend on the adhesion strength of coatings on substrates, which is often quantified or defined in terms of the energy released on per unit film/substrate delamination area, i.e., the so-called energy release rate.…”

Antimicrobial activity of silver-coated hollow poly(methylmethacrylate) microspheres for water decontamination

“…Among the metal ions, silver exhibits the highest toxicity for microorganisms and minimum toxicity towards animal cells. The excellent biocidal property combined with nontoxicity towards human cells [22,23] makes silver one of the highest priority materials for water purification. The antimicrobial spectrum of silver is extensive, including Gram-negative enterobacteria and Gram-positive cocci [24][25][26].…”

“…Hence, AgNPs have been either adsorbed on or embedded in various organic or inorganic substrates which include filter materials made of silica, zeolite, natural macroporous materials, carbon materials, fiberglass and polymers or paper of different types [36][37][38][39][40][41]. For instance, nanoparticles of silver were embedded in materials like, montmorillonites [23], polysulfone [42] cellulose acetate [37], fiberglass [43], polyurethane foams [44], ceramic filters [45][46][47][48] and activated carbon [49] to enhance their applicability, especially for water purification system. However, many times these materials associate with the drawbacks like relatively poor disinfection of water and poor structural stability in water purification system.…”