More Like this

1. Transepithelial electrical impedance increase following porous substrate electroporation enables label-free delivery

   Brooks, Justin R; Heiman, Tyler C; Lorenzen, Sawyer R; Mungloo, Ikhlaas; Mirfendereski, Siamak; Park, Jae Sung; Yang, Ruiguo (February 2024, Small)

   Porous substrate electroporation (PSEP) is a promising new method for intracellular delivery, yet fundamentals of PSEP are not well understood, especially the intermediate processes leading to delivery. PSEP is an electrical method, yet the relationship between PSEP and electrical impedance remains underexplored. In this study, a device capable of measuring impedance and performing PSEP is developed and the changes in transepithelial electrical impedance (TEEI) are monitored. These measurements show TEEI increases following PSEP, unlike other electroporation methods. The authors then demonstrate how cell culture conditions and electrical waveforms influence this response. More importantly, TEEI response features are correlated with viability and delivery efficiency, allowing prediction of outcomes without fluorescent cargo, imaging, or image processing. This label-free delivery also allows improved temporal resolution of transient processes following PSEP, which the authors expect will aid PSEP optimization for new cell types and cargos. 

   more » « less
2. Robust Three-dimensional Nanotube-in-Micropillar Array Electrodes to Facilitate Size Independent Electroporation in Blood Cell Therapy

   https://doi.org/10.1039/D1LC00690H  

   Liu, Xuan; Chang, An-Yi; Ma, Yifan; Hua, Liping; Yang, Zhaogang; Wang, Shengnian (September 2021, Lab on a Chip)

   null (Ed.)

   Blood is an attractive carrier for plasmid and RNA based medicine in cell therapy. Electroporation serves as its favorable delivery tool for simple operation, quick internalization, minimum cell culture involvement, and low contamination risk. However, the delivery outcomes of electroporation heavily depend on the treated cells such as their type, size, and orientation to the electric field, not ideal for highly heterogeneous blood samples. Herein a new electroporation system was developed towards effective transfection to cells in blood regardless their large diversity. By coupling replica molding and infiltration coating processes, we successfully configured a three-dimensional electrode comprised of a polymer micropillar array on which carbon nanotubes (CNTs) are partially embedded. During electroporation, cells sag between micropillars and deform to form conformal contact with their top and side surface. The implanted CNTs not only provide a robust conductive coating for the polymer micropattern, but also have their protruded ends face the cell membrane vertically everywhere with maximum transmembrane potential. Regardless their largely varied sizes and random dispersion, both individual blood cell type and whole blood samples were effectively transfected with plasmid DNA (85% after 24 hrs and 95% after 72 hrs, or 2.5-3.0 folds enhancement). High-dose RNA probes were also introduced which regulate better the expression levels of exogenous and endogenous genes in blood cells. Besides its promising performance on non-viral delivery route to cell-related studies and therapy, the invovled new fabrication method also provides a convenient and effective way to construct flexible electronics with stable micro/nanofeatures on the surface. 

   more » « less
3. Neural Network‐Enabled Multiparametric Impedance Signal Templating for High throughput Single‐Cell Deformability Cytometry Under Viscoelastic Extensional Flows

   https://doi.org/10.1002/smll.202407212  

   Jarmoshti, Javad; Siddique, Abdullah‐Bin; Rane, Aditya; Mirhosseini, Shaghayegh; Adair, Sara J; Bauer, Todd W; Caselli, Federica; Swami, Nathan S (October 2024, Small)

   Abstract Cellular biophysical metrics exhibit systematic alterations during processes, such as metastasis and immune cell activation, which can be used to identify and separate live cell subpopulations for targeting drug screening. Image‐based biophysical cytometry under extensional flows can accurately quantify cell deformability based on cell shape alterations but needs extensive image reconstruction, which limits its inline utilization to activate cell sorting. Impedance cytometry can measure these cell shape alterations based on electric field screening, while its frequency response offers functional information on cell viability and interior structure, which are difficult to discern by imaging. Furthermore, 1‐D temporal impedance signal trains exhibit characteristic shapes that can be rapidly templated in near real‐time to extract single‐cell biophysical metrics to activate sorting. We present a multilayer perceptron neural network signal templating approach that utilizes raw impedance signals from cells under extensional flow, alongside its training with image metrics from corresponding cells to derive net electrical anisotropy metrics that quantify cell deformability over wide anisotropy ranges and with minimal errors from cell size distributions. Deformability and electrical physiology metrics are applied in conjunction on the same cell for multiparametric classification of live pancreatic cancer cells versus cancer associated fibroblasts using the support vector machine model. 

   more » « less
4. Investigation of the Electrical properties of Phosphatidylserine Lipid Bilayer Membranes

   https://doi.org/10.1109/SoutheastCon48659.2022.9764102  

   Tantawi, Khalid H.; Hunnicutt, Hope; McSpadden, Dottie; Martino, Victoria; Patel, Darayas; Musa, Yasmin (March 2022, Proceeding of the 2022 IEEE Southeast Conference)

   In this work we investigate the electrical properties of phospholipid bilayer membranes (LBMs) formed from phosphatidylserine by analyzing two experimental setups. The Electrochemical Impedance Spectra (EIS) of phosphatidylserine show that a lipid bilayer membrane formed from this phospholipid has an average specific electrical resistance of 3.466 k Ω.cm 2 and an average capacitance of 0.385 µF/cm 2 . Some of the major factors that affect the LBM resistance include electroporation, the method of deposition, and the surface tension in microchannels for supported LBMs. Therefore, wide apertures remain the most accurate method for supporting LBMs. 

   more » « less
5. A comparison of inverted and upright laser-activated titanium nitride micropyramids for intracellular delivery

   https://doi.org/10.1038/s41598-018-33885-y  

   Raun, Alexander; Saklayen, Nabiha; Zgrabik, Christine; Shen, Weilu; Madrid, Marinna; Huber, Marinus; Hu, Evelyn; Mazur, Eric (December 2018, Scientific Reports)

   Abstract The delivery of biomolecules into cells relies on porating the plasma membrane to allow exterior molecules to enter the cell via diffusion. Various established delivery methods, including electroporation and viral techniques, come with drawbacks such as low viability or immunotoxicity, respectively. An optics-based delivery method that uses laser pulses to excite plasmonic titanium nitride (TiN) micropyramids presents an opportunity to overcome these shortcomings. This laser excitation generates localized nano-scale heating effects and bubbles, which produce transient pores in the cell membrane for payload entry. TiN is a promising plasmonic material due to its high hardness and thermal stability. In this study, two designs of TiN micropyramid arrays are constructed and tested. These designs include inverted and upright pyramid structures, each coated with a 50-nm layer of TiN. Simulation software shows that the inverted and upright designs reach temperatures of 875 °C and 307 °C, respectively, upon laser irradiation. Collectively, experimental results show that these reusable designs achieve maximum cell poration efficiency greater than 80% and viability greater than 90% when delivering calcein dye to target cells. Overall, we demonstrate that TiN microstructures are strong candidates for future use in biomedical devices for intracellular delivery and regenerative medicine. 

   more » « less