## Other Nanotechnology Applications
### Validate Theoretic and Experimental Electric Field in Electrolyte with Platinum Capillary Electrode  
[PERSON], [PERSON] and [PERSON]  
Department of Electrical Engineering, University of Florida, Gainesville, FL, USA  
Nanoscience Institute for Medical and Engineering Technology (NIMET), Gainesville, FL, USA  
The neural electrodes play a significant and noticeable role in curing human nervous system in restoring motor and sensory functions for disabled patients by electrical stimulation of nerve tissue and recording of neural electrical activity. In neural engineering and electrode implantation, the potential field is a pivotal parameter to measure and control to avoid or minimize the damages of the nerves and around tissues. Herein, we describe a method to validate the performance of algorithm and spatial voltage drop-off experiment. Therefore, the electric potential field can be obtained conveniently by using drop-off voltage experiment to estimate the electrodes' functions. In the algorithm section, it is fully based on three-electrode system and is simplified by simplifying the modeling circuit after accurate calculation or controlled experimental setup. We use the Metrohm potentiostat to realize electrochemical impedance spectroscopy experiments obtaining the solution conductivities which will be using to model the resistivity of solutions in algorithm. In the experiment section, to simulate disk electrode using in stimulation, the 254 \(\upmu\)m platinum wire is inserted in hollow capillary. Four different concentrations of solution (0.2 mM, 0.04 mM, 0.008 mM, 0.0016 mM) are used to validate the theory and experiment to make sure the results are the same. Then in three-electrode system, the Thorlabs manual stage is used to control the drop-off voltage distance accurately and slowly. At the beginning, the working and counter electrodes are connected to get the original voltage in the solutions. Moreover, with rotating the stage knob, the distance between two electrodes increases, at the same time, the voltage or the electric potential drops a lot and the voltage drops less and less gradually as the distance goes relatively far. Macromolecular Crowding Modulates the Organization of Actin Bundles Induced by Actin Crosslinking Proteins  
[PERSON] \({}^{\text{a,b}}\), [PERSON] \({}^{\text{a}}\), [PERSON] \({}^{\text{a}}\), [PERSON] \({}^{\text{a,c}}\), [PERSON] \({}^{\text{a,d}}\) and [PERSON] \({}^{\text{a,b,d,*}}\)  
\({}^{\text{a}}\) NanoScience Technology Center, University of Central Florida, Orlando, FL 32826, USA* Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32816, USA
* Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
* Department of Physics, University of Central Florida, Orlando, FL 32816, USA
* Correspondence: [PERSON]RESS]  
Actin is the essential cytoskeletal protein that plays critical roles in numerous cellular process including cell morphogenesis and movement. Actin crosslinking proteins such as fascin and \(\alpha\)-actinin are involved in forming higher-ordered bundles in various cellular structures including filopodia and lamellipodia. Macromolecular crowding agents are widely used to understand protein binding and assembly in intracellular environment. While the roles of actin crosslinking proteins in bundling have been well studied in dilute buffer conditions, how they affect bundle organization in crowded environments is not well established. Here, we investigate how macromolecular crowding modulates the organization of fascin- or \(\alpha\)-actinin-induced bundles in vitro and in silico. Total internal reflection fluorescence (TIRF) microscopy and atomic force microscopy (AFM) imaging reveal that fascin enhances the packing density of bundles in the presence of crowders, while \(\alpha\)-actinin reduces the number of filaments per bundle with crowding.