化学
表面电荷
扫描离子电导显微镜
电导
电荷密度
电解质
离子
分析化学(期刊)
德拜长度
显微镜
电荷(物理)
扫描电化学显微镜
纳米技术
电极
材料科学
光学
电化学
扫描共焦电子显微镜
色谱法
物理
有机化学
物理化学
量子力学
凝聚态物理
作者
Jake Rabinowitz,Andreas Hartel,Hannah Dayton,Jason D. Fabbri,Jeanyoung Jo,Lars E. P. Dietrich,Kenneth L. Shepard
标识
DOI:10.1021/acs.analchem.2c05303
摘要
Scanning ion conductance microscopy (SICM) is a topographic imaging technique capable of probing biological samples in electrolyte conditions. SICM enhancements have enabled surface charge detection based on voltage-dependent signals. Here, we show how the hopping mode SICM method (HP-SICM) can be used for rapid and minimally invasive surface charge mapping. We validate our method usingPseudomonas aeruginosaPA14 (PA) cells and observe a surface charge density of σPA = −2.0 ± 0.45 mC/m2 that is homogeneous within the ∼80 nm lateral scan resolution. This biological surface charge is detected from at least 1.7 μm above the membrane (395× the Debye length), and the long-range charge detection is attributed to electroosmotic amplification. We show that imaging with a nanobubble-plugged probe reduces perturbation of the underlying sample. We extend the technique to PA biofilms and observe a charge density exceeding −20 mC/m2. We use a solid-state calibration to quantify surface charge density and show that HP-SICM cannot be quantitatively described by a steady-state finite element model. This work contributes to the body of scanning probe methods that can uniquely contribute to microbiology and cellular biology.
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