The role of charge on the diffusion of solutes and nanoparticles (silicon nanocrystals, nTiO2, nAu) in a biofilm
The role of charge on the diffusion of solutes and nanoparticles (silicon nanocrystals, nTiO2, nAu) in a biofilm
复制标题
DOI：
10.1071/en12106
复制
发表时间：
2013-01-01
影响因子：
4.3
通讯作者：
Wilkinson, Kevin J.
中科院分区：
文献类型：
--
作者：
Golmohamadi, Mahmood;Clark, Rhett J.;Wilkinson, Kevin J.
考察了溶质和生物膜电荷对生物膜中自扩散(布朗运动)的影响。用荧光相关光谱(FCS)测定了几种模型(荧光)溶质(罗丹明B、四甲基罗丹明甲酯、俄勒冈绿488羧酸、丁二酰亚胺酯和俄勒冈绿488羧酸)和纳米粒子(功能化硅、金和钛)的扩散系数(D)。有些令人惊讶的是，由于电荷对生物膜中扩散测量的影响很小。此外，对于带正负电荷的探针，生物膜中扩散系数与水中扩散系数的比率(D-b/D-w)在很大的离子强度范围内(0.1-100 mm)几乎保持不变。相反，尺寸为>；10 nm的纳米粒子在生物膜中的自扩散系数比在水中的大大降低。此外，更大的纳米颗粒(>；66 nm)似乎完全被生物膜排除在外。结果表明，对于环境中的许多寡营养生物膜，溶质和纳米颗粒的扩散将主要受阻碍而不是静电相互作用的控制。结果还表明，当纳米材料的尺寸超过10纳米时，它们的流动性和生物利用度将显著降低(对非浮游生物)。
The effect of solute and biofilm charge on self-diffusion (Brownian motion) in biofilms is examined. Diffusion coefficients (D) of several model (fluorescent) solutes (rhodamine B; tetramethylrhodamine, methyl ester; Oregon Green 488 carboxylic acid, succinimidyl ester and Oregon Green 488 carboxylic acid) and nanoparticles (functionalised silicon, gold and titanium) were determined using fluorescence correlation spectroscopy (FCS). Somewhat surprisingly, little effect due to charge was observed on the diffusion measurements in the biofilms. Furthermore, the ratio of the diffusion coefficient in the biofilm with respect to that in water (D-b/D-w) remained virtually constant across a wide range of ionic strengths (0.1-100 mM) for both negatively and positively charged probes. In contrast, the self-diffusion coefficients of nanoparticles with sizes >10 nm greatly decreased in the biofilms with respect to those in water. Furthermore, much larger nanoparticles (>66 nm) appeared to be completely excluded from the biofilms. The results indicated that for many oligotrophic biofilms in the environment, the diffusion of solutes and nanoparticles will be primarily controlled by obstruction rather than electrostatic interactions. The results also imply that most nanomaterials will become significantly less mobile and less bioavailable (to non-planktonic organisms) as they increase in size beyond similar to 10 nm.