Portoporator©: A portable low-cost electroporation device for gene transfer to cultured cells in biotechnology, biomedical research and education

Atoh1 overexpression promotes Guinea pig bone marrow mesenchymal stem cells to differentiate into neural stem cell

Sensorineural hearing loss (SNHL) is a prevalent condition in otolaryngology. A key obstacle is finding effective strategies for regenerating damaged cochlear hair cells in adult animals. A practical and reliable approach has been developed to create a superior cell source for stem cell transplantation in the inner ear to treat SNHL. Atoh1 is involved in the differentiation of neurons, intestinal secretory cells, and mechanoreceptors including auditory hair cells, and thus plays an important role in neurogenesis. Lentivirus-mediated transfection of bone marrow mesenchymal stem cells (BMSCs) was utilized to achieve stable expression of the essential transcription factor Atoh1, which is crucial for developing auditory hair cells without compromising cell survival. By manipulating the induction conditions through altering the cell growth environment using anti-adherent culture, the synergistic impact of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) was effectively applied to significantly improve the differentiation efficiency of bone marrow-derived mesenchymal stem cells (BMSC) into neural stem cells (NSCs) following Atoh1 transfection, thereby reducing the induction time. The study indicated that the newly proposed transdifferentiation method effectively transformed BMSCs into NSCs in a controlled environment, presenting a potential approach for stem cell transplantation to promote hair cell regeneration.

An efficient low cost means of biophysical gene transfection in primary cells

Efficient, facile gene modification of cells has become an indispensable part of modern molecular biology. For the majority of cell lines and several primary populations, such modifications can be readily performed through a variety of methods. However, many primary cell lines such as stem cells frequently suffer from poor transfection efficiency. Though several physical approaches have been introduced to circumvent these issues, they often require expensive/specialized equipment and/or consumables, utilize substantial cell numbers and often still suffer from poor efficiency. Viral methods are capable of transducing difficult cellular populations, however such methods can be time consuming for large arrays of gene targets, present biohazard concerns, and result in expression of viral proteins; issues of concern for certain experimental approaches. We report here a widely applicable, low-cost (< $100 CAD) method of electroporation, applicable to small (1-10 μl) cell volumes and composed of equipment readily available to the average investigator. Using this system we observe a sixfold increase in transfection efficiency in embryonic stem cell lines compared to commercial devices. Due to efficiency gains and reductions in volume and applied voltage, this process improves the survival of sensitive stem cell populations while reducing reagent requirements for protocols such as Cas9/gRNAs transfections.

NeuroPorator: An open-source, current-limited electroporator for safe in utero gene transfer

BACKGROUND

Electroporation is an effective technique for genetic manipulation of cells, both in vitro and in vivo. In utero electroporation (IUE) is a special case, which represents a fine application of this technique to genetically modify specific tissues of embryos during prenatal development. Commercially available electroporators are expensive and not fully customizable. We have designed and produced an inexpensive, open-design, and customizable electroporator optimized for safe IUE. We introduce NeuroPorator.

METHOD

We used off-the-shelf electrical parts, a single-board microcontroller, and a cheap data logger to build an open-design electroporator. We included a safety circuit to limit the applied electrical current to protect the embryos. We added full documentation, design files, and assembly instructions.

RESULT

NeuroPorator output is on par with commercially available devices. Furthermore, the adjustable current limiter protects both the embryos and the uterus from overcurrent damage. A built-in data acquisition module provides real-time visualization and recordings of the actual voltage/current pulses applied to each embryo. Function of NeuroPorator has been demonstrated by inducing focal cortical dysplasia in mice.

SIGNIFICANCE AND CONCLUSION

The simple and fully open design enables quick and cheap construction of the device and facilitates further customization. The features of NeuroPorator can accelerate the IUE technique implementation in any laboratory and speed up its learning curve.

A low-voltage alternant direct current electroporation chip for ultrafast releasing the genome DNA of Helicobacter pylori bacterium

Nucleic acid detection, as an important molecular diagnostic method, is widely used in bacterial identification, disease diagnosis. For detecting the nucleic acid of bacteria, the prerequisite is to release nucleic acids inside the bacteria. The common means to release nucleic acids is the chemical method, which involves complex processes, is time-consuming, and remains chemical inhibitors. Compared with chemical methods, electroporation as a physical method has the advantages of easy operation, short-time consumption, and chemical reagents free. However, the current works using electroporation often necessitates high-frequency or high-voltage conditions, entailing bulky power devices. Herein, we propose a low-voltage alternant direct current (LADC) electroporation chip and the corresponding miniature device for ultrafast releasing the genome DNA from Helicobacter pylori (H. pylori) for detection. We connected a micrometer-interdigital electrode in the chip with a 20 V portable battery to make the miniature device. Using this low-voltage device, our chip released genome DNA of H. pylori within only 5 ms, achieving a cell lysis rate of 99.5%. We further combined this chip with a colorimetric loop-mediated isothermal amplification assay to visually detect H. pylori within ~ 25 min at 10 CFU/μL. We detected 11 clinical samples using the chip, and the detection results were consistent with those of the clinical standard. The results indicate that the LADC electroporation chip is useful for ultrafast release of genome DNA from bacteria and is expected to promote the development of nucleic acid detection in POCT and other scenarios.

Tissue Nanotransfection Silicon Chip and Related Electroporation-Based Technologies for In Vivo Tissue Reprogramming

Tissue nanotransfection (TNT), a cutting-edge technique of in vivo gene therapy, has gained substantial attention in various applications ranging from in vivo tissue reprogramming in regenerative medicine, and wound healing to cancer treatment. This technique harnesses the advancements in the semiconductor processes, facilitating the integration of conventional transdermal gene delivery methods-nanoelectroporation and microneedle technologies. TNT silicon chips have demonstrated considerable promise in reprogramming fibroblast cells of skin in vivo into vascular or neural cells in preclinical studies to assist in the recovery of injured limbs and damaged brain tissue. More recently, the application of TNT chips has been extended to the area of exosomes, which are vital for intracellular communication to track their functionality during the wound healing process. In this review, we provide an in-depth examination of the design, fabrication, and applications of TNT silicon chips, alongside a critical analysis of the electroporation-based gene transfer mechanisms. Additionally, the review discussed the existing limitations and challenges in the current technique, which may project future trajectories in the landscape of gene therapy. Through this exploration, the review aims to shed light on the prospects of TNT in the broader context of gene therapy and tissue regeneration.

Piezoelectric Transformer-Based High-Voltage Pulse Generator Using Wide-Bandgap Semiconductors for Medical Electroporation Therapy

In this paper, a new application of Piezoelectric Transformer (PT)-based power converters to generate high-voltage (HV) bipolar pulses for medical electroporation therapy is proposed. In particular, PT-based power conversion is investigated as an alternative to magnetics-based approaches of generating HV from a relatively low-voltage (LV) input source for application in electroporation therapy. The detailed PT-based system design and selection of wide bandgap semiconductor switches such as GaN FETs, high-voltage SiC diodes and SiC MOSFETs, as well as simulation results to demonstrate proof-of-concept using LTSpice are presented. Preliminary experimental results of the PT-based capacitor charger are shown, and work is ongoing to develop a complete hardware prototype of the proposed HV pulse generator.

Assessment of Cell Viability in Electrically Excitable Muscle Cells Through Intact Twitch Stimulation

Muscle cells (i.e. skeletal muscle fibers) are fully viable and functional when their excitation-contraction (EC) coupling machinery is intact. This involves intact membrane integrity with polarized membrane, functional ion channels for action potential generation and conduction, an intact electro-chemical interface at the level of the fiber's triad, followed by sarcoplasmic reticulum Ca²⁺ release, and subsequent activation of the chemico-mechanical interface at the level of the contractile apparatus. The ultimate end result is then a visible twitch contraction upon a brief electrical pulse stimulation. For many biomedical studies involving single muscle cells, intact and viable myofibers are of utmost importance. Thus, a simple global screening method that involves a brief electrical stimulus applied to single muscle fibers and assessment of visible contraction would be of high value. In this chapter, we describe step-by-step protocols to (i) obtain intact single muscle fibers from freshly dissected muscle tissue using an enzymatic digestion procedure and (ii) provide a workflow for the assessment of twitch response of single fibers that can be ultimately classified as viable. For this, we have prepared a unique stimulation pen for which we provide the fabrication guide for do-it-yourself rapid prototyping to eliminate the need for expensive specialized commercial equipment.

Recent Advances in Stimulus-Responsive Nanocarriers for Gene Therapy

Gene therapy provides a promising strategy for curing monogenetic disorders and complex diseases. However, there are challenges associated with the use of viral delivery vectors. The advent of nanomedicine represents a quantum leap in the application of gene therapy. Recent advances in stimulus-responsive nonviral nanocarriers indicate that they are efficient delivery systems for loading and unloading of therapeutic nucleic acids. Some nanocarriers are responsive to cues derived from the internal environment, such as changes in pH, redox potential, enzyme activity, reactive oxygen species, adenosine triphosphate, and hypoxia. Others are responsive to external stimulations, including temperature gradients, light irradiation, ultrasonic energy, and magnetic field. Multiple stimuli-responsive strategies have also been investigated recently for experimental gene therapy.

Mediated amperometry as a prospective method for the investigation of electroporation

Pulsed electric field effects induced in a membrane, as well as intracellular structures, depend on cell type, field and media parameters. To achieve desired outcomes, membranes should be permeabilized in a controlled manner, and thus efficiency of electroporation should be investigated in advance. Here, we present a framework for using mediated amperometry as a prospective method for the investigation of electroporation and its effects on cellular machinery. Whole-cell sensors with single mediator systems comprised of hydrophilic or lipophilic mediators were successfully employed to investigate membrane permeability as well as cellular responses. Exposure of yeast cells to single electric field pulse (τ = 300 µs, E = 16 kV/cm) resulted in up to tenfold increase of current strength mediated with hydrophilic mediators. Exposure to PEF resulted in decrease of menadione mediated current strength (from 138 ± 15 to 32 ± 15 nA), which could be completely compensated by supplementing electrolyte with NADH.

Concepts and Capabilities of In-House Built Nanosecond Pulsed Electric Field (nsPEF) Generators for Electroporation: State of Art

Electroporation is a pulsed electric field triggered phenomenon of cell permeabilization, which is extensively used in biomedical and biotechnological context. There is a growing scientific demand for high-voltage and/or high-frequency pulse generators for electropermeabilization of cells (electroporators). In the scope of this article we have reviewed the basic topologies of nanosecond pulsed electric field (nsPEF) generators for electroporation and the parametric capabilities of various in-house built devices, which were introduced in the last two decades. Classification of more than 60 various nsPEF generators was performed and pulse forming characteristics (pulse shape, voltage, duration and repetition frequency) were listed and compared. Lastly, the trends in the development of the electroporation technology were discussed.

3D Printed Lab-on-a-Chip Platform for Chemical Stimulation and Parallel Analysis of Ion Channel Function

Functional imaging has been a widely established method for the assessment of ion channel function in vitro. Conventional infrastructure used for in vitro functional analysis of ion channels is typically proprietary, non-customizable, expensive, and requires a high level of skill to use and maintain. 3D desktop printing, which is employed in the rapid prototyping field, allows for quick engineering of alternatives to conventional imaging infrastructure that are customizable, low cost, and user friendly. Here, we describe an ultra-low-cost microfluidic lab-on-a-chip (LOC) device manufactured using acrylonitrile butadiene styrene (ABS) for in vitro functional imaging of ion channels that can quickly and easily be reconstructed using three-dimensional (3D) desktop printing. The device is light weight (<5 g), small (20 mm × 49 mm), and extremely low cost (<EUR 1). We simulate fluidics within the printed channels and assess the suitability of the engineered chamber to generate homogeneous mixtures during solution exchange. We demonstrate the usability of the 3D printed microfluidic device in a case study using Fluo-4-loaded human embryonal kidney-derived (HEK293) cells, recombinantly expressing the capsaicin receptor, transient receptor potential vanilloid receptor type 1 (TRPV1), as a model system. In the case study, we confirm its applicability to solution exchange for chemical stimulation and parallel functional time-lapse fluorescence microscopy-based calcium imaging. We assess the suitability of ABS for culturing HEK293 cells inside the microfluidic LOC, based on qualitative analysis of microscopic transmission light images of ABS-exposed HEK293 cells and confirm the previously reported biocompatibility of ABS. To highlight the versatility of the 3D printed microfluidic device, we provide an example for multiplication of the shown concept within a 3D printed multichannel microfluidic LOC to be used, for example, in a higher throughput format for parallelized functional analysis of ion channels. While this work focusses on Ca²⁺ imaging with TRPV1 channels, the device may also be useful for application with other ion channel types and in vitro models.

Ultra-Low-Cost 3D Bioprinting: Modification and Application of an Off-the-Shelf Desktop 3D-Printer for Biofabrication

3D bioprinting has become a versatile and powerful method in tissue engineering and regenerative medicine and is increasingly adapted by other disciplines due to its tremendous potential beyond its typical applications. However, commercially available 3D bioprinting systems are typically expensive circumventing the broad implementation, including laboratories in low-resource settings. To address the limitations of conventional and commercially available technology, we developed a 3D bioprinter by modification of an off-the-shelf 3D desktop printer, that can be installed within a single day, is of handy size to fit into a standard laminar flow hood, customizable, ultra-low cost and thus, affordable to a broad range of research labs, or educational institutions. We evaluate accuracy and reproducibility of printing results using alginate and alginate/gelatin-hydrogels and demonstrate its potential for biomedical use by printing of various two-and three-dimensional cell-free and mammalian cell-laden objects using recombinant HEK^YFP cells, stably expressing yellow fluorescent protein (YFP) as a model system and high-content imaging. We further provide a parts list and 3D design files in STL and STEP format for reconstructing the device. A time-lapse video of the custom-built device during operation is available at https://vimeo.com/274482794.