Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5936_Библиотеки_им_академика_М_И_Перельмана

C-dots lead to an inhibition of the bacterial growth or eliminate them by using compli­cated mechanisms of action such as the production of ROS, disintegrating the structure of the cells, and fragmenting and condensing genomic DNA, resulting in the cytoplasm leak­age [82]. The excellent antibacterial effects (on both gram-positive and gram-negative bac­teria) were reported by Dou et al. for multifunctional C-dots derived from glucose and poly(ethylenimine) and quaternized with benzyl bromide, although the synthesis took place over a 12-h period. As the quaternized C-dots have positive surface charges, they at­tach to the cell membrane of bacteria and disrupt it [118]. These effects are attributed to the surface charges of C-dots and ROS production. As Bing et al. indicated in their study, spermine-functionalized C-dots with positive charges exerted antibacterial effects on E. coli primarily by ROS production as they mainly disrupted the electrostatic interactions [119]. Accordingly, different potential pathways have been proposed in various studies for the antimicrobial effects of these materials, including physical/mechanical damage, ROS­induced, oxidative stress, photocatalytic impacts, and bacterial metabolism inhibition [120–122]. The first mechanism, which includes physical/mechanical destruction of the bac­terial cell wall or external membrane, results in cytoplasm leakage, subsequently leading to its dysfunction and bacteriostatic as well as bactericidal impacts as the most prevalent antibacterial mechanisms. As an example, C-dots with less toxicity and higher biodegrad­ability were provided by Li et al., using a one-step electrochemical therapeutic method of vitamin C [24, 120]. Antimicrobial mechanisms of C-dots are presented in Figure 11.3 [82].