Condition optimization for electroporation transfection in horse skeletal muscle satellite cells

Satellite cells are an important cellular model for studying muscle growth and development and mammalian locomotion-related molecular mechanisms. In this study, we investigated the effects of voltage, pulse duration, and DNA dosage on horse skeletal muscle satellite cells' electroporation transfection efficiency using the eukaryotic expression plasmid Td Tomato-C1 (5.5 kb) encoding the red fluorescent protein gene mainly based on fluorescence-positive cell rate and cell survival rate. By comparison of different voltages, pulse durations, and DNA doses, horse skeletal muscle satellite cells have nearly 80% transfection efficiency under the condition of voltage 120 V, DNA dosage 7 µg/ml, and pulse duration 30 ms. This optimized electroporation condition would facilitate the application of horse skeletal muscle satellite cells in genetic studies of muscle function and related diseases.

Optimizing CRISPR/Cas9 approaches in the polymorphic tunicate Ciona intestinalis

CRISPR/Cas9 became a powerful tool for genetic engineering and in vivo knockout also in the invertebrate chordate Ciona intestinalis. Ciona (ascidians, tunicates) is an important model organism because it shares developmental features with the vertebrates, considered the sister group of tunicates, and offers outstanding experimental advantages: a compact genome and an invariant developmental cell lineage that, combined with electroporation mediated transgenesis allows for precise and cell type specific targeting in vivo. A high polymorphism and the mosaic expression of electroporated constructs, however, often hamper the efficient CRISPR knockout, and an optimization in Ciona is desirable. Furthermore, seasonality and artificial maintenance settings can profit from in vitro approaches that would save on animals. Here we present improvements for the CRISPR/Cas9 protocol in silico, in vitro and in vivo. Firstly, in designing sgRNAs, prior sequencing of target genomic regions from experimental animals and alignment with reference genomes of C. robusta and C. intestinalis render a correction possible of subspecies polymorphisms. Ideally, the screening for efficient and non-polymorphic sgRNAs will generate a database compatible for worldwide Ciona populations. Secondly, we challenged in vitro assays for sgRNA validation towards reduced in vivo experimentation and report their suitability but also overefficiency concerning mismatch tolerance. Thirdly, when comparing Cas9 with Cas9:Geminin, thought to synchronize editing and homology-direct repair, we could indeed increase the in vivo efficiency and notably the access to an early expressed gene. Finally, for in vivo CRISPR, genotyping by next generation sequencing (NGS) ex vivo streamlined the definition of efficient single guides. Double CRISPR then generates large deletions and reliable phenotypic excision effects. Overall, while these improvements render CRISPR more efficient in Ciona, they are useful when newly establishing the technique and very transferable to CRISPR in other organisms.

MRI-guided stereotactic ablative body radiotherapy versus CT-guided percutaneous irreversible electroporation for locally advanced pancreatic cancer (CROSSFIRE): a single-centre, open-label, randomised phase 2 trial

BACKGROUND

Pancreatic ductal adenocarcinoma is an aggressive disease with a dismal prognosis. Stage III locally advanced pancreatic cancer is considered unresectable and current palliative chemotherapy regimens only modestly improve survival. Guidelines suggest chemoradiation or stereotactic ablative body radiotherapy (SABR) could be beneficial in certain circumstances. Other local treatments such as irreversible electroporation could enhance patient outcomes by extending survival while preserving quality of life. We aimed to compare the efficacy and safety of MRI-guided SABR versus CT-guided percutaneous irreversible electroporation following standard FOLFIRINOX chemotherapy.

METHODS

CROSSFIRE was an open-label, randomised phase 2 superiority trial conducted at the Amsterdam University Medical Centre (Amsterdam, Netherlands). Eligible patients were aged 18 years or older with confirmed histological and radiological stage III locally advanced pancreatic cancer. The maximum tumour diameter was 5 cm and patients had to be pretreated with three to eight cycles of FOLFIRINOX. Patients were randomly assigned (1:1) to MRI-guided SABR (five fractions of 8 Gy delivered on non-consecutive days) or CT-guided percutaneous irreversible electroporation using a computer-generated variable block randomisation model. The primary endpoint was overall survival from randomisation, assessed in the intention-to-treat population. Safety was assessed in the per-protocol population. A prespecified interim futility analysis was done after inclusion of half the original sample size, with a conditional probability of less than 0·2 resulting in halting of the study. The trial was registered at ClinicalTrials.gov, NCT02791503.

FINDINGS

Between May 1, 2016, and March 31, 2022, 68 patients were enrolled and randomly assigned to SABR (n=34) or irreversible electroporation (n=34), of whom 64 were treated according to protocol. Of the 68 participants, 36 (53%) were male and 32 (47%) were female, with a median age of 65 years (IQR 57-70). Median overall survival from randomisation was 16·1 months (95% CI 12·1-19·4) in the SABR group versus 12·5 months (10·9-17·0) in the irreversible electroporation group (hazard ratio [HR] 1·39 [95% CI 0·84-2·30]; p=0·21). The conditional probability to demonstrate superiority of either technique was 0·13; patient accrual was therefore stopped early for futility. 20 (63%) of 32 patients in the SABR group versus 19 (59%) of 32 patients in the irreversible electroporation group had adverse events (p=0·8) and five (16%) patients in the SABR group versus eight (25%) in the irreversible electroporation group had grade 3-5 adverse events (p=0·35). The most common grade 3-4 adverse events were cholangitis (two [6%] in the SABR group vs one [3%] in the irreversible electroporation group), abdominal pain (one [3%] vs two [6%]), and pancreatitis (none vs two [6%]). One (3%) patient in the SABR group and one (3%) in the irreversible electroporation group died from a treatment-related adverse event.

INTERPRETATION

CROSSFIRE did not identify a difference in overall survival or incidence of adverse events between MRI-guided SABR and CT-guided percutaneous irreversible electroporation after FOLFIRINOX. Future studies should further assess the added value of local ablative treatment over chemotherapy alone.

FUNDING

Adessium Foundation, AngioDynamics.

Homologous Overexpression of Tyrosinase in Trichoderma reesei and Its Application in Glycinin Cross-Linking

Tyrosinase is capable of oxidizing tyrosine residues in proteins, leading to intermolecular protein cross-linking, which could modify the protein network of food and improve the texture of food. To obtain the recombinant tyrosinase with microbial cell factory instead of isolation tyrosinase from the mushroom Agaricus bisporus, a TYR expression cassette was constructed in this study. The expression cassette was electroporated into Trichoderma reesei Rut-C30 and integrated into its genome, resulting in a recombinant strain C30-TYR. After induction with microcrystalline cellulose for 7 days, recombinant tyrosinase could be successfully expressed and secreted by C30-TYR, corresponding to approximately 2.16 g/L tyrosinase in shake-flask cultures. The recombinant TYR was purified by ammonium sulfate precipitation and gel filtration, and the biological activity of purified TYR was 45.6 U/mL. The purified TYR could catalyze the cross-linking of glycinin, and the emulsion stability index of TYR-treated glycinin emulsion was increased by 30.6% compared with the untreated one. The cross-linking of soy glycinin by TYR resulted in altered properties of oil-in-water emulsions compared to emulsions stabilized by native glycinin. Therefore, cross-linking with this recombinant tyrosinase is a feasible approach to improve the properties of protein-stabilized emulsions and gels.

Molecular Simulations Reveal the Free Energy Landscape and Transition State of Membrane Electroporation

The formation of pores over lipid membranes by the application of electric fields, termed membrane electroporation, is widely used in biotechnology and medicine to deliver drugs, vaccines, or genes into living cells. Continuum models for describing the free energy landscape of membrane electroporation were proposed decades ago, but they have never been tested against spatially detailed atomistic models. Using molecular dynamics (MD) simulations with a recently proposed reaction coordinate, we computed potentials of mean force of pore nucleation and pore expansion in lipid membranes at various transmembrane potentials. Whereas the free energies of pore expansion are compatible with previous continuum models, the experimentally important free energy barrier of pore nucleation is at variance with established models. The discrepancy originates from different geometries of the transition state; previous continuum models assumed the presence of a membrane-spanning defect throughout the process, whereas, according to the MD simulations, the transition state of pore nucleation is typically passed before a transmembrane defect has formed. A modified continuum model is presented that qualitatively agrees with the MD simulations. Using kinetics of pore opening together with transition state theory, our free energies of pore nucleation are in excellent agreement with previous experimental data.

Collaborative Optimization Design of Self-Powered Sterilizer with Highly Efficient Synergistic Antibacterial Effect

The development of self-powered sterilizers has garnered significant attention in the scientific and engineering fields. However, there remains an urgent need to improve their sterilization efficiency. In this study, we present a self-powered sterilizer with superior antibacterial capability by maximizing the utilization of breakdown discharge generated by a soft-contact freestanding rotary triboelectric nanogenerator (FR-TENG). To achieve this, a collaborative optimization strategy is proposed, encompassing the structural design of the FR-TENG, the implementation of double voltage rectification, and manipulation of the gaseous phase. Through a comprehensive analysis of antibacterial rates and microscopic images, the effectiveness of the self-powered sterilizer against various types of bacteria, including Gram-positive and Gram-negative species, as well as mixed bacteria in natural seawater, is demonstrated. Further investigations into bacterial morphologies and solution compositions reveal that the synergistic effect between electroporation and the generation of reactive oxygen/nitrogen species contributes to efficient sterilization. Additionally, controlled trials and molecular dynamics simulations are conducted to quantitatively elucidate the synergistic antibacterial effect between electroporation and reactive oxygen/nitrogen species. This study highlights the effectiveness of the collaborative optimization strategy in enhancing the sterilization efficiency of self-powered sterilizers while providing valuable insights into the synergistic antibacterial mechanisms of physical and chemical sterilization.

Protocol for differential multi-omic analyses of distinct cell types in the mouse cerebral cortex

Here, we present a protocol for differential multi-omic analyses of distinct cell types in the developing mouse cerebral cortex. We describe steps for in utero electroporation, subsequent flow-cytometry-based isolation of developing mouse cortical cells, bulk RNA sequencing or quantitative liquid chromatography-tandem mass spectrometry, and bioinformatic analyses. This protocol can be applied to compare the proteomes and transcriptomes of developing mouse cortical cell populations after various manipulations (e.g., epigenetic). For complete details on the use and execution of this protocol, please refer to Meka et al. (2022).1.

Novel electroporation-based genome editing of carnation plant tissues using RNPs targeting the anthocyanidin synthase gene

MAIN CONCLUSION

A novel electroporation method for genome editing was performed using plant tissue samples by direct RNPs-introduction in carnation. Genome editing is becoming a very useful tool in plant breeding. In this study, a novel electroporation method was performed for genome editing using plant tissue samples. The objective was to create a flower color mutant using the pink-flowered carnation 'Kane Ainou 1-go'. For this purpose, a ribonucleoprotein consisting of guide RNA and clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) was introduced into the stem tissue to induce mutations in the anthocyanidin synthase (ANS) gene, which is involved in anthocyanin biosynthesis. As the ANS of 'Kane Ainou 1-go' has not been previously isolated, we initially isolated the ANS gene from 'Kane Ainou 1-go' for characterization. Southern hybridization analysis confirmed that the ANS gene was present in the genome as a two-allele gene with a pair of homologous sequences (ANS-1 and 2); these sequences were used as the target for genome editing. Genome editing was performed by introducing #2_single-guide RNA into the stem tissue using the ribonucleoprotein. This molecule was used because it exhibited the highest efficiency in an analysis of cleavage activity against the target sequence in vitro. Cleaved amplified polymorphic sequence analysis of genomic DNA extracted from 85 regenerated individuals after genome editing was performed. The results indicated that mutations in the ANS gene may have been introduced into two lines. Cloning of the ANS gene in these two lines confirmed the introduction of a single nucleotide substitution mutation for ANS-1 in both lines, and a single amino acid substitution in one line. We discussed the possibility of color change by the amino acid substitution, and also the future applications of this technology.

Nasopharyngeal carcinoma cell screening based on the electroporation-SERS spectroscopy

Nasopharyngeal carcinoma (NPC) is a malignant tumor in head and neck. Early diagnosis can effectively improve the survival rate of patients. Nasopharyngeal exfoliative cytology, as a convenient and noninvasive auxiliary diagnostic method, is suitable for the population screening of NPC, but its diagnostic sensitivity is low. In this study, an electroporation-based SERS technique was proposed to detect and screen the clinical nasopharyngeal exfoliated cell samples. Firstly, nasopharyngeal swabs was used to collected the nasopharyngeal exfoliated cell samples from NPC patients (n = 54) and healthy volunteers (n = 60). Then, gold nanoparticles, as the Raman scattering enhancing substrates, were rapidly introduced into cells by electroporation technique for surface-enhanced Raman scattering (SERS) detection. Finally, SERS spectra combined with principal component analysis (PCA) and linear discriminant analysis (LDA) were employed to diagnose and distinguish NPC cell samples. Raman peak assignments combined with spectral differences reflected the biochemical changes associated with NPC, including nucleic acid, amino acid and carbohydrates. Based on the PCA-LDA approach, the sensitivity, specificity and accuracy of 98.15 %, 96.67 % and 97.37 %, respectively, were achieved for screening NPC. This study offers valuable assistance for noninvasive NPC auxiliary diagnosis, and has grate potential in expanding the application of the SERS technique in clinical cell sample testing.

Utilizing Human-Induced Pluripotent Stem Cells to Study Cardiac Electroporation Pulsed-Field Ablation

BACKGROUND

Electroporation is a promising nonthermal ablation method for cardiac arrhythmia treatment. Although initial clinical studies found electroporation pulsed-field ablation (PFA) both safe and efficacious, there are significant knowledge gaps concerning the mechanistic nature and electrophysiological consequences of cardiomyocyte electroporation, contributed by the paucity of suitable human in vitro models. Here, we aimed to establish and characterize a functional in vitro model based on human-induced pluripotent stem cells (hiPSCs)-derived cardiac tissue, and to study the fundamentals of cardiac PFA.

METHODS

hiPSC-derived cardiomyocytes were seeded as circular cell sheets and subjected to different PFA protocols. Detailed optical mapping, cellular, and molecular characterizations were performed to study PFA mechanisms and electrophysiological outcomes.

RESULTS

PFA generated electrically silenced lesions within the hiPSC-derived cardiac circular cell sheets, resulting in areas of conduction block. Both reversible and irreversible electroporation components were identified. Significant electroporation reversibility was documented within 5 to 15-minutes post-PFA. Irreversibly electroporated regions persisted at 24-hours post-PFA. Per single pulse, high-frequency PFA was less efficacious than standard (monophasic) PFA, whereas increasing pulse-number augmented lesion size and diminished reversible electroporation. PFA augmentation could also be achieved by increasing extracellular Ca2+ levels. Flow-cytometry experiments revealed that regulated cell death played an important role following PFA. Assessing for PFA antiarrhythmic properties, sustainable lines of conduction block could be generated using PFA, which could either terminate or isolate arrhythmic activity in the hiPSC-derived cardiac circular cell sheets.

CONCLUSIONS

Cardiac electroporation may be studied using hiPSC-derived cardiac tissue, providing novel insights into PFA temporal and electrophysiological characteristics, facilitating electroporation protocol optimization, screening for potential PFA-sensitizers, and investigating the mechanistic nature of PFA antiarrhythmic properties.

Direct Measurements of FLASH-Induced Changes in Intracellular Oxygenation

PURPOSE

The goal of our study was to characterize the dynamics of intracellular oxygen during application of radiation at conventional (CONV) and FLASH dose rates and obtain evidence for or against the oxygen depletion hypothesis as a mechanism of the FLASH effect.

METHODS AND MATERIALS

The measurements were performed by the phosphorescence quenching method using probe Oxyphor PtG4, which was delivered into the cellular cytosol by electroporation.

RESULTS

Intracellular radiochemical oxygen depletion (ROD) g-value for a dose rate of 100 Gy/s in the normoxic range was found to be 0.58 ± 0.03 μM/Gy. Intracellular ROD g-values for FLASH and CONV dose rates in the normoxic range were found to be nearly equal. As in solution-based studies, intracellular ROD was found to exhibit strong dependence on oxygen concentration in the range of 0 to ∼40 μM [O2].

CONCLUSIONS

Depletion of oxygen in cells in vitro by a clinical dose of proton radiation delivered as FLASH is unable to produce a transient state of hypoxia and, therefore, unable to induce radioprotection. The difference between ROD g-values for FLASH and CONV dose rates, detected previously in solutions-based experiments, disappears when measurements are conducted inside cells. Understanding this phenomenon should provide additional insight into the role of oxygen in FLASH radiation therapy and help to decipher the mechanism of the FLASH effect.

Elevating intracellular action potential recording in cardiomyocytes: A precision-enhanced and biosafe single-pulse electroporation system

Action potentials play a pivotal role in diverse cardiovascular physiological mechanisms. A comprehensive understanding of these intricate mechanisms necessitates a high-fidelity intracellular electrophysiological investigative approach. The amalgamation of micro-/nano-electrode arrays and electroporation confers substantial advantages in terms of high-resolution intracellular recording capabilities. Nonetheless, electroporation systems typically lack precise control, and commonly employed electroporation modes, involving tailored sequences, may escalate cellular damage and perturbation of normal physiological functions due to the multiple or higher-intensity electrical pulses. In this study, we developed an innovative electrophysiological biosensing system customized to facilitate precise single-pulse electroporation. This advancement serves to achieve optimal and uninterrupted intracellular action potential recording within cardiomyocytes. The refinement of the single-pulse electroporation technique is realized through the integration of the electroporation and assessment biosensing system, thereby ensuring a consistent and reliable means of achieving stable intracellular access. Our investigation has unveiled that the optimized single-pulse electroporation technique not only maintains robust biosafety standards but also enables the continuous capture of intracellular electrophysiological signals across an expansive three-day period. The universality of this biosensing system, adaptable to various micro/nano devices, furnishes real-time analysis and feedback concerning electroporation efficacy, guaranteeing the sustained, secure, and high-fidelity acquisition of intracellular data, thereby propelling the field of cardiovascular electrophysiological research.

Characterization of two distinct immortalized endothelial cell lines, EA.hy926 and HMEC-1, for in vitro studies: exploring the impact of calcium electroporation, Ca2+ signaling and transcriptomic profiles

BACKGROUND

Disruption of Ca2+ homeostasis after calcium electroporation (CaEP) in tumors has been shown to elicit an enhanced antitumor effect with varying impacts on healthy tissue, such as endothelium. Therefore, our study aimed to determine differences in Ca2+ kinetics and gene expression involved in the regulation of Ca2+ signaling and homeostasis, as well as effects of CaEP on cytoskeleton and adherens junctions of the established endothelial cell lines EA.hy926 and HMEC-1.

METHODS

CaEP was performed on EA.hy926 and HMEC-1 cells with increasing Ca2+ concentrations. Viability after CaEP was assessed using Presto Blue, while the effect on cytoskeleton and adherens junctions was evaluated via immunofluorescence staining (F-actin, α-tubulin, VE-cadherin). Differences in intracellular Ca2+ regulation ([Ca2+]i) were determined with spectrofluorometric measurements using Fura-2-AM, exposing cells to DPBS, ionomycin, thapsigargin, ATP, bradykinin, angiotensin II, acetylcholine, LaCl3, and GdCl3. Molecular distinctions were identified by analyzing differentially expressed genes and pathways related to the cytoskeleton and Ca2+ signaling through RNA sequencing.

RESULTS

EA.hy926 cells, at increasing Ca2+ concentrations, displayed higher CaEP susceptibility and lower survival than HMEC-1. Immunofluorescence confirmed CaEP-induced, time- and Ca2+-dependent morphological changes in EA.hy926's actin filaments, microtubules, and cell-cell junctions. Spectrofluorometric Ca2+ kinetics showed higher amplitudes in Ca2+ responses in EA.hy926 exposed to buffer, G protein coupled receptor agonists, bradykinin, and angiotensin II compared to HMEC-1. HMEC-1 exhibited significantly higher [Ca2+]i changes after ionomycin exposure, while responses to thapsigargin, ATP, and acetylcholine were similar in both cell lines. ATP without extracellular Ca2+ ions induced a significantly higher [Ca2+]i rise in EA.hy926, suggesting purinergic ionotropic P2X and metabotropic P2Y receptor activation. RNA-sequencing analysis showed significant differences in cytoskeleton- and Ca2+-related gene expression, highlighting upregulation of ORAI2, TRPC1, TRPM2, CNGA3, TRPM6, and downregulation of TRPV4 and TRPC4 in EA.hy926 versus HMEC-1. Moreover, KEGG analysis showed upregulated Ca2+ import and downregulated export genes in EA.hy926.

CONCLUSIONS

Our finding show that significant differences in CaEP response and [Ca2+]i regulation exist between EA.hy926 and HMEC-1, which may be attributed to distinct transcriptomic profiles. EA.hy926, compared to HMEC-1, displayed higher susceptibility and sensitivity to [Ca2+]i changes, which may be linked to overexpression of Ca2+-related genes and an inability to mitigate changes in [Ca2+]i. The study offers a bioinformatic basis for selecting EC models based on research objectives.

Neoadjuvant calcium electroporation for potentially curable colorectal cancer

BACKGROUND

The development of new perioperative treatment modalities to activate the immune system in colorectal cancer might have a beneficial effect on reducing the risk of recurrence after surgery. Calcium electroporation is a promising treatment modality that potentially modulates the tumor microenvironment. The aim of this study was to evaluate the safety of the procedure in the neoadjuvant setting in localized left-sided colorectal cancer (CRC).

METHODS

The study included patients with potentially curable sigmoid or rectal cancer with no indication for other neoadjuvant treatment. Patients were offered calcium electroporation as a neoadjuvant treatment before elective surgery. Follow-up visits were conducted on the preoperative day before elective surgery, POD2, POD14, and POD30, with an evaluation of adverse events, impact on elective surgery, clinical examination, and quality of recovery.

RESULTS

Endoscopic calcium electroporation was performed as an outpatient procedure in all 21 cases, with no procedure-related complications reported. At follow-up, five adverse events were registered, two of which were classified as serious adverse events. Surgery was performed as planned in 19 patients (median time to surgery, 8 days), and the final two patients underwent surgery with a delay due to adverse events (14 and 33 days). No significant impact on the quality of recovery scores nor inflammatory markers were seen before and after calcium electroporation, nor baseline and POD30.

CONCLUSIONS

Endoscopic calcium electroporation is a safe and feasible procedure in patients with potentially curable CRC. The study showed limited side effects and limited impact on the following elective surgical resection.

Efficient engineering of human and mouse primary cells using peptide-assisted genome editing

Simple, efficient and well-tolerated delivery of CRISPR genome editing systems into primary cells remains a major challenge. Here we describe an engineered Peptide-Assisted Genome Editing (PAGE) CRISPR-Cas system for rapid and robust editing of primary cells with minimal toxicity. The PAGE system requires only a 30-min incubation with a cell-penetrating Cas9 or Cas12a and a cell-penetrating endosomal escape peptide to achieve robust single and multiplex genome editing. Unlike electroporation-based methods, PAGE gene editing has low cellular toxicity and shows no significant transcriptional perturbation. We demonstrate rapid and efficient editing of primary cells, including human and mouse T cells, as well as human hematopoietic progenitor cells, with editing efficiencies upwards of 98%. PAGE provides a broadly generalizable platform for next-generation genome engineering in primary cells.

Irreversible Electroporation of the Hepatobiliary System: Current Utilization and Future Avenues

Liver cancer remains a leading cause of cancer-related deaths worldwide despite numerous advances in treatment. While surgical resection remains the gold standard for curative treatment, it is only possible for a minority of patients. Thermal ablation is an effective option for the treatment of smaller tumors; however, its use is limited to tumors that are not located in proximity to sensitive structures due to the heat sink effect and the potential of thermal damage. Irreversible electroporation (IRE) is a non-thermal ablative modality that can deliver targeted treatment and the effective destruction of tumors that are in close proximity to or even surrounding vascular or biliary ducts with minimal damage to these structures. IRE produces short pulses of high-frequency energy which opens pores in the lipid bilayer of cells leading to apoptosis and cell death. IRE has been utilized clinically for over a decade in the treatment of liver cancers with multiple studies documenting an acceptable safety profile and high efficacy rates.

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.

Rapid estimation of electroporation-dependent tissue properties in canine lung tumors using a deep neural network

The efficiency of electroporation treatments depends on the application of a critical electric field over the targeted tissue volume. Both the electric field and temperature distribution strongly depend on the tissue-specific electrical properties, which both differ between patients in healthy and malignant tissues and change in an electric field-dependent manner from the electroporation process itself. Therefore, tissue property estimations are paramount for treatment planning with electroporation therapies. Ex vivo methods to find electrical tissue properties often misrepresent the targeted tissue, especially when translating results to tumors. A voltage ramp is an in situ method that applies a series of increasing electric potentials across treatment electrodes and measures the resulting current. Here, we develop a robust deep neural network, trained on finite element model simulations, to directly predict tissue properties from a measured voltage ramp. There was minimal test error (R2>0.94;p<0.0001) in three important electric tissue properties. Further, our model was validated to correctly predict the complete dynamic conductivity curve in a previously characterized ex vivo liver model (R2>0.93;p<0.0001) within 100 s from probe insertion, showing great utility for a clinical application. Lastly, we characterize the first reported electrical tissue properties of lung tumors from five canine patients (R2>0.99;p<0.0001). We believe this platform can be incorporated prior to treatment to quickly ascertain patient-specific tissue properties required for electroporation treatment planning models or real-time treatment prediction algorithms. Further, this method can be used over traditional ex vivo methods for in situ tissue characterization with clinically relevant geometries.

Calcium Electroporation versus Electrochemotherapy with Bleomycin in an In Vivo CAM-Based Uveal Melanoma Xenograft Model

Despite recent advancements in the diagnosis and treatment of uveal melanoma (UM), its metastatic rate remains high and is accompanied by a highly dismal prognosis, constituting an unmet need for the development of novel adjuvant therapeutic strategies. We established an in vivo chick chorioallantoic membrane (CAM)-based UM xenograft model from UPMD2 and UPMM3 cell lines to examine its feasibility for the improvement of selection of drug candidates. The efficacy of calcium electroporation (CaEP) with 5 or 10 mM calcium chloride (Ca) and electrochemotherapy (ECT) with 1 or 2.5 µg/mL bleomycin in comparison to monotherapy with the tested drug or electroporation (EP) alone was investigated on the generated UM tumors. CaEP and ECT showed a similar reduction of proliferation and melanocytic expansion with a dose-dependent effect for bleomycin, whereas CaEP induced a significant increase of the apoptosis and a reduction of vascularization with varying sensitivity for the two xenograft types. Our in vivo results suggest that CaEP and ECT may facilitate the adequate local tumor control and contribute to the preservation of the bulbus, potentially opening new horizons in the adjuvant treatment of advanced UM.

Effects of Voltage and Treatment Time of Pulsed Electric Field on Electroporation in Rhizoctonia solani

The pulsed electric field (PEF) of μs duration can induce electroporation by causing permanent damage to the membrane, leading to cell death. The microbe was treated by a homemade PEF generator instrument. The sterilization effect of PEF on the Rhizoctonia solani was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM), and the leakage of the intracellular contents was measured with a conductometer and an ultraviolet spectrophotometer. The increases in the electrical conductivity and the optical density (OD) value indicated that the cell membrane was damaged, and the intracellular contents overflowed. As a result, according to our experimental conditions, the optimum condition was the high-pulsed electric voltage of 26 kV, and the treatment time was 4 min. It could be concluded that the PEF could damage the cell membrane, and the ratio of electroporation reached 100%, which provides a new method of killing R. solani efficiently.

A multiplexed microfluidic continuous-flow electroporation system for efficient cell transfection

Cellular therapies have the potential to advance treatment for a broad array of diseases but rely on viruses for genetic reprogramming. The time and cost required to produce viruses has created a bottleneck that constricts development of and access to cellular therapies. Electroporation is a non-viral alternative for genetic reprogramming that bypasses these bottlenecks, but current electroporation technology suffers from low throughput, tedious optimization, and difficulty scaling to large-scale cell manufacturing. Here, we present an adaptable microfluidic electroporation platform with the capability for rapid, multiplexed optimization with 96-well plates. Once parameters are optimized using small volumes of cells, transfection can be seamlessly scaled to high-volume cell manufacturing without re-optimization. We demonstrate optimizing transfection of plasmid DNA to Jurkat cells, screening hundreds of different electrical waveforms of varying shapes at a speed of ~3 s per waveform using ~20 µL of cells per waveform. We selected an optimal set of transfection parameters using a low-volume flow cell. These parameters were then used in a separate high-volume flow cell where we obtained similar transfection performance by design. This demonstrates an alternative non-viral and economical transfection method for scaling to the volume required for producing a cell therapy without sacrificing performance. Importantly, this transfection method is disease-agnostic with broad applications beyond cell therapy.

Genetically engineered HEK cells as a valuable tool for studying electroporation in excitable cells

Electric pulses used in electroporation-based treatments have been shown to affect the excitability of muscle and neuronal cells. However, understanding the interplay between electroporation and electrophysiological response of excitable cells is complex, since both ion channel gating and electroporation depend on dynamic changes in the transmembrane voltage (TMV). In this study, a genetically engineered human embryonic kidney cells expressing NaV1.5 and Kir2.1, a minimal complementary channels required for excitability (named S-HEK), was characterized as a simple cell model used for studying the effects of electroporation in excitable cells. S-HEK cells and their non-excitable counterparts (NS-HEK) were exposed to 100 µs pulses of increasing electric field strength. Changes in TMV, plasma membrane permeability, and intracellular Ca2+ were monitored with fluorescence microscopy. We found that a very mild electroporation, undetectable with the classical propidium assay but associated with a transient increase in intracellular Ca2+, can already have a profound effect on excitability close to the electrostimulation threshold, as corroborated by multiscale computational modelling. These results are of great relevance for understanding the effects of pulse delivery on cell excitability observed in context of the rapidly developing cardiac pulsed field ablation as well as other electroporation-based treatments in excitable tissues.

High throughput intracellular delivery by viscoelastic mechanoporation

Brief pulses of electric field (electroporation) and/or tensile stress (mechanoporation) have been used to reversibly permeabilize the plasma membrane of mammalian cells and deliver materials to the cytosol. However, electroporation can be harmful to cells, while efficient mechanoporation strategies have not been scalable due to the use of narrow constrictions or needles which are susceptible to clogging. Here we report a high throughput approach to mechanoporation in which the plasma membrane is stretched and reversibly permeabilized by viscoelastic fluid forces within a microfluidic chip without surface contact. Biomolecules are delivered directly to the cytosol within seconds at a throughput exceeding 250 million cells per minute. Viscoelastic mechanoporation is compatible with a variety of biomolecules including proteins, RNA, and CRISPR-Cas9 ribonucleoprotein complexes, as well as a range of cell types including HEK293T cells and primary T cells. Altogether, viscoelastic mechanoporation appears feasible for contact-free permeabilization and delivery of biomolecules to mammalian cells ex vivo.

Recombinant Production of Food Allergens in Yeast Pichia pastoris

The methylotrophic yeast Pichia pastoris (P. pastoris) is one of the expression systems widely used to produce recombinant heterologous proteins. In this chapter, the methodology to produce recombinant food allergens in P. pastoris is described. The methodology begins with the preparation of competent P. pastoris cells followed by the transformation of the competent cells by electroporation as well as the preparation of plasmid DNA for transformation. Moreover, the screening of yeast transformants by direct PCR to ensure integration of allergen DNA followed by small-scale expression of recombinant allergen in yeast cells is also described.

Electroporation-mediated genome editing in vitrified/warmed porcine zygotes obtained in vitro

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) system is the most efficient and widely used technology for genome editing in all sorts of organisms, including livestock animals. Here, we examined the feasibility of CRISPR/Cas9-derived genome editing (GE) in vitrified porcine zygotes, where the flexible planning of experiments in time and space is expected. OCT4 and CD46 genes were targeted, and the Cas9/sgRNA ribonucleoprotein complexes (RNP) were electroporated into zygotes at 2 h after warming. Vitrification or GE alone did not significantly reduce the developmental rates to the blastocyst stage. However, vitrification followed by GE significantly reduced blastocyst development. Sequencing analysis of the resultant blastocysts revealed efficient GE for both OCT4 (nonvitrified: 91.0%, vitrified: 95.1%) and CD46 (nonvitrified: 94.5%, vitrified: 93.2%), with no significant difference among them. Immunocytochemical analysis showed that GE-blastocysts lacked detectable proteins. They were smaller in size, and the cell numbers were significantly reduced compared with the control (p < 0.01). Finally, we demonstrated that double GE efficiently occurs (100%) when the OCT4-RNP and CD46-RNP are simultaneously introduced into zygotes after vitrification/warming. This is the first demonstration that vitrified porcine zygotes can be used in GE as efficiently as nonvitrified ones.

Studying Secretory Protein Synthesis in Nicotiana benthamiana Protoplasts

Transient gene expression in plant protoplasts facilitates the analysis of hybrid genes in a fast and reproducible manner. The technique is particularly powerful when studying basic conserved biochemical processes including de novo protein synthesis, modification, assembly, transport, and turnover. Unlike individual plants, protoplast suspensions can be divided into almost identical aliquots, allowing the analysis of independent variables with uncertainties restricted to minor pipetting errors/variations. Using the examples of protein secretion and ER retention, we describe the most advanced working practice of routinely preparing, electroporating, and analyzing Nicotiana benthamiana protoplasts. A single batch of electroporation-competent protoplasts permits up to 30 individual transfections. This is ideal to assess the influence of independent variables, such as point mutations, deletions or fusions, or the influence of a co-expressed effector gene in dose-response studies.

An Optimized Protocol for piggyBac-Induced iPSC Generation from hPBMCs by Automatic Electroporation

Thanks to the Yamanaka transcription factors, pluripotency is recovered in the cell culture dish during in vitro cell reprogramming. Induced pluripotent stem cells (iPSCs) have been introduced to the scientific world as a source of disease models, which are predominantly used in drug discovery and monitoring disease pathophysiology, and as a source of master cell lines for developing cellular therapies. Successfully attaining iPSCs requires careful optimization of many factors, including selection of the transfection method and the appropriate transfection agents; culturing conditions before and after transfection; recovery conditions after transfection, freezing, and thawing; storage conditions; and the choice of cost-effective cell and colony characterization and molecular verification steps. In our optimized procedure, we describe the isolation of peripheral blood mononuclear cells (PBMCs) after blood harvest and their efficient reprogramming into iPSCs using automated electroporator, with piggyBac.

Brain Sample Preparation After Performing in Utero Electroporation to Proliferating and Differentiated Cells in the Developing Mouse Neocortex

In utero electroporation (IUE) enables labeling and manipulating specific types of cells by introducing DNA plasmids with desired promoters. After the surgery, mouse brains are fixed at any stage and analyzed after staining using specific antibodies. Here, we describe the flow of the IUE experiment from the preparation to microscopic observations.

Cancer Modeling by Transgene Electroporation in Adult Zebrafish (TEAZ)

Transgenic expression of genes is a mainstay of cancer modeling in zebrafish. Traditional transgenic techniques rely upon injection into one-cell embryos, but ideally these transgenes would be expressed only in adult somatic tissues. We provide a method to model cancer in adult zebrafish in which transgenes can be expressed via electroporation. Using melanoma as an example, we demonstrate the feasibility of expressing oncogenes such as BRAFV600E as well as CRISPR/Cas9 inactivation of tumor suppressors such as PTEN. These approaches can be performed in any genetic background such as existing fluorophore reporter lines or the casper line. These methods can readily be extended to other cell types allowing for rapid adult modeling of cancer in zebrafish.

Dynamics of Cell Death Due to Electroporation Using Different Pulse Parameters as Revealed by Different Viability Assays

The mechanisms of cell death due to electroporation are still not well understood. Recent studies suggest that cell death due to electroporation is not an immediate all-or-nothing response but rather a dynamic process that occurs over a prolonged period of time. To investigate whether the dynamics of cell death depends on the pulse parameters or cell lines, we exposed different cell lines to different pulses [monopolar millisecond, microsecond, nanosecond, and high-frequency bipolar (HFIRE)] and then assessed viability at different times using different viability assays. The dynamics of cell death was observed by changes in metabolic activity and membrane integrity. In addition, regardless of pulse or cell line, the dynamics of cell death was observed only at high electroporation intensities, i.e., high pulse amplitudes and/or pulse number. Considering the dynamics of cell death, the clonogenic assay should remain the preferred viability assay for assessing viability after electroporation.

A rapid and efficient method using electroporation for releasing intracellular microcystin toxins from cultured and naturally occurring cyanobacterial cells in lake water

In cyanotoxin measurements, effective release of intracellular cyanotoxins through cell lysis is pivotal. The conventional method for cell lysis is repeated freeze-thaw (F-T), which has several disadvantages, including poor reproducibility since it is operator and equipment dependency and time-consuming. In this study, a rapid and sensitive method was developed using irreversible electroporation, reducing quantification time by over 6 h compared to F-T. Focusing on microcystins (MCs), we developed the most optimal electroporation medium (50 mM Tris (pH 7.0) with 0.5 % SDS) and determined the optimal intensity of electroporation using Microcystis culture. Microcystis cell rupture was validated by scanning electron microscopy. COMSOL simulations mirrored experimental conditions. Compared to F-T, this new method generated an average 13.7 % (6.7 ppb) more MCs from lake water samples (p ≥ 0.05). This innovation, surpassing the time-consuming F-T process, emerges as a valuable tool for timely decision-making in water safety advisory and cyanotoxin management in various settings.

Irreversible Electroporation of the Liver Increases the Transplant Engraftment of Hepatocytes

INTRODUCTION

Irreversible electroporation (IRE) is a tissue ablation technology that kills cells with short electrical pulses that do not induce thermal damage, thereby preserving the extracellular matrix. Preclinical research suggests that IRE may be developed as a tool for regenerative surgery by clearing existing host cells within a solid organ and creating a supportive niche for new cell engraftment. We hypothesized that hepatocytes transplanted by injection into the portal circulation would preferentially engraft within liver parenchyma pretreated with IRE.

METHODS

Transgene-positive β-galactosidase-expressing hepatocytes were isolated from B6.129S7-Gt(ROSA)26Sor/J (ROSA26) mice and transplanted by intrasplenic injection into wild-type littermates that received liver IRE pretreatment or control sham treatment. Engraftment of donor hepatocytes in recipient livers was determined by X-gal staining.

RESULTS

Significantly higher numbers of X-gal+ donor hepatocytes engrafted in the livers of IRE-treated mice as compared to sham-treated mice. X-gal+ hepatocytes persisted in IRE-treated recipients for at least 11 d post-transplant and formed clusters. Immunostaining demonstrated the presence of HNF4A/Ki67/β-galactosidase triple-positive cells within IRE-ablation zones, indicating that transplanted hepatocytes preferentially engrafted in IRE-treated liver parenchyma and proliferated.

CONCLUSIONS

IRE pretreatment of the liver increased engraftment of transplanted hepatocytes within the IRE-ablation zone. IRE treatment of the host liver may be developed clinically as a strategy to increase engraftment efficiency of primary hepatocytes and/or hepatocytes derived from stem cells in cell transplant therapies.

Live Imaging of Migrating Neurons and Glial Progenitors Visualized by in Utero Electroporation

During cortical development, both neurons and glial cells are generated in the germinal zone near the lateral ventricle, migrate in the correct direction, and settle in their appropriate locations. This developmental process can be clearly visualized by introducing fluorescent protein-expression vectors via in utero electroporation. In this chapter, we describe labeling methods for migrating neurons and glial progenitors, as well as methods for slice culture, and time-lapse imaging.

Ultrasonic Electroporation for Cells Grown on Piezoelectric Film Composed of Hydroxyapatite Nanowire and PVDF

The delivery of cell impermeable exogenous material into live cells by external stimuli is critical for both biological research and therapeutic applications. Although electroporation-based delivery of foreign materials inside the cell is a powerful approach, cell viability is often compromised due to the requirement of high voltage. Here, we report a piezoelectric hydroxyapatite nanowire-embedded poly(vinylidene fluoride) (PVDF) film for ultrasonic electroporation-based delivery of foreign materials to adherent cells. We found that 9 wt % loading of hydroxyapatite nanowires into PVDF can enhance the piezoelectric property by 2-3 times (with a piezoelectric constant value of 58 pm/V) than pure PVDF/nanowire, which is comparable to commonly known piezoelectric ceramics. These films can harvest mechanical as well as ultrasound-based energy to produce electrical potential up to 2 V. This biocompatible film can be used to grow cells on top of it and for subsequent application of ultrasound to exert electric voltage on cell membrane. We found that ultrasonic exposure to adhered cells leads to reversible pore formation on cell membrane that offers intracellular delivery of FITC-dextran with 75% efficiency. The developed piezoelectric film-based ultrasonic electroporation can be used for wireless electroporation in remote areas.

Mapping Kenyon cell inputs in Drosophila using dye electroporation

Here, we describe a technique for charting the inputs of individual Kenyon cells in the Drosophila brain. In this technique, a single Kenyon cell per brain hemisphere is photo-labeled to visualize its claw-like dendritic terminals; a dye-filled electrode is used to backfill the projection neuron connected to each claw. This process can be repeated in hundreds of brains to build a connectivity matrix. Statistical analyses of such a matrix can reveal connectivity patterns such as random input and biased connectivity. For complete details on the use and execution of this protocol, please refer to Hayashi et al. (2022).1.

Microneedle Electroporation for Intralesional Administration of Corticosteroid Treatment of Keloid Scar

Abstract is missing (Short communication)

Electroporation-based CRISPR gene editing in adult buffalo fibroblast cells

Electroporation is a widely used method for delivering CRISPR components into cells; however, it presents challenges when applied to difficult-to-transfect cells like adult buffalo fibroblasts. In this study, the ITGB2 gene (encoding the CD18 protein), plays vital for cellular adhesion and immune responses, was selected for editing experiments. To optimize electroporation conditions, we investigated parameters such as electric field strength, pulse duration, plasmid DNA amount, cuvette type, and cell type. The best transfection rates were obtained in a 4 mm gap cuvette with a single 20-millisecond pulse of 300 V using a 10 μg of all-in-one CRISPR plasmid for 106 cells in 100 μL of electroporation buffer. Increasing DNA quantity enhanced transfection rates but compromised cell viability. The 4 mm cuvette gap had high transfection rates than the 2 mm gap, and newborn cells exhibited higher transfection rates than adult cells. We achieved transfection rates of 10-12% with a cell viability of 25-30% for adult fibroblast cells. Subsequently, successfully edited the ITGB2 gene with a 30% editing efficiency, confirmed through various analysis methods, including T7E1 assay, TIDE and ICE analysis, and TA cloning. In conclusion, electroporation conditions reported here can edit buffalo gene(s) for various biotechnological research applications.

Musa acuminata as electroporation model

Electrochemotherapy (ECT) and Irreversible electroporation (IRE) are cancer treatments based on electric field distribution in tissues. Solanum tuberosum (potato tissue) phantom is known to mimic changes in the electrical conductivity that occur in animal tissues during electroporation (EP). Electric field distribution is assessed through enzymatic staining. However, the 24-h wait for this assessment could slow agile response scenarios. We developed and validated the Musa acuminata (cavendish banana) conductivity model, which quickly evaluates EP by tissue staining. We investigated the frequency response of the tissue using impedance spectroscopy analysis, conductivity changes, and enzymatic staining. We optimized three usual EP models: adapted Gompertz, smoothed Heaviside, and the sigmoid or logistic function. We found dielectric parameters in banana tissue similar to those in potato (electrical conductivity of 0.035 S/m and relative permittivity of 4.1×104). The coefficients of determination R2 were 99.94% (Gompertz), 99.85% (Heaviside), and 99.58% (sigmoid). The sigmoid and Heaviside functions described the calibration and validation electric currents with 95% confidence. We observed the electroporated areas in bananas 3h30m after EP. Staining was significant after 450 V/cm. The conductivity model of Musa acuminata suits treatment planning, hardware development, and training scenarios. Banana phantom supports the 3Rs practice and is a reliable alternative for potato in EP studies.

Changes of Ex Vivo Cervical Epithelial Cells Due to Electroporation with JMY

The ionic environment within the nucleoplasm might diverge from the conditions found in the cytoplasm, potentially playing a role in the cellular stress response. As a result, it is conceivable that interactions of nuclear actin and actin-binding proteins (ABPs) with apoptosis factors may differ in the nucleoplasm and cytoplasm. The primary intracellular stress response is Ca2+ influx. The junctional mediating and regulating Y protein (JMY) is an actin-binding protein and has the capability to interact with the apoptosis factor p53 in a Ca2+-dependent manner, forming complexes that play a regulatory role in cytoskeletal remodelling and motility. JMY's presence is observed in both the cytoplasm and nucleoplasm. Here, we show that ex vivo ectocervical squamous cells subjected to electroporation with JMY protein exhibited varying morphological alterations. Specifically, the highly differentiated superficial and intermediate cells displayed reduced nuclear size. In inflamed samples, nuclear enlargement and simultaneous cytoplasmic reduction were observable and showed signs of apoptotic processes. In contrast, the less differentiated parabasal and metaplastic cells showed increased cytoplasmic activity and the formation of membrane protrusions. Surprisingly, in severe inflammation, vaginosis or ASC-US (Atypical Squamous Cells of Undetermined Significance), JMY appears to influence only the nuclear and perinuclear irregularities of differentiated cells, and cytoplasmic abnormalities still existed after the electroporation. Our observations can provide an appropriate basis for the exploration of the relationship between cytopathologically relevant morphological changes of epithelial cells and the function of ABPs. This is particularly important since ABPs are considered potential diagnostic and therapeutic biomarkers for both cancers and chronic inflammation.

Electroporation-based delivery of proteins in Penium margaritaceum and other zygnematophycean algae

Zygnematophycean algae represent the streptophyte group identified as the closest sister clade to land plants. Their phylogenetic position and growing genomic resources make these freshwater algae attractive models for evolutionary studies in the context of plant terrestrialization. However, available genetic transformation protocols are limited and exclusively DNA-based. To expand the zygnematophycean toolkit, we developed a DNA-free method for protein delivery into intact cells using electroporation. We use confocal microscopy coupled with fluorescence lifetime imaging to assess the delivery of mNeonGreen into algal cells. We optimized the method to obtain high efficiency of delivery and cell recovery after electroporation in two strains of Penium margaritaceum and show that the experimental setup can also be used to deliver proteins in other zygnematophycean species such as Closterium peracerosum-strigosum-littorale complex and Mesotaenium endlicherianum. We discuss the possible applications of this proof-of-concept method.

Engineering Efficient CAR-T Cells via Electroactive Nanoinjection

Chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising cell-based immunotherapy approach for treating blood disorders and cancers, but genetically engineering CAR-T cells is challenging due to primary T cells' sensitivity to conventional gene delivery approaches. The current viral-based method can typically involve significant operating costs and biosafety hurdles, while bulk electroporation (BEP) can lead to poor cell viability and functionality. Here, a non-viral electroactive nanoinjection (ENI) platform is developed to efficiently negotiate the plasma membrane of primary human T cells via vertically configured electroactive nanotubes, enabling efficient delivery (68.7%) and expression (43.3%) of CAR genes in the T cells, with minimal cellular perturbation (>90% cell viability). Compared to conventional BEP, the ENI platform achieves an almost threefold higher CAR transfection efficiency, indicated by the significantly higher reporter GFP expression (43.3% compared to 16.3%). By co-culturing with target lymphoma Raji cells, the ENI-transfected CAR-T cells' ability to effectively suppress lymphoma cell growth (86.9% cytotoxicity) is proved. Taken together, the results demonstrate the platform's remarkable capacity to generate functional and effective anti-lymphoma CAR-T cells. Given the growing potential of cell-based immunotherapies, such a platform holds great promise for ex vivo cell engineering, especially in CAR-T cell therapy.

Adaptive design of mRNA-loaded extracellular vesicles for targeted immunotherapy of cancer

The recent success of mRNA therapeutics against pathogenic infections has increased interest in their use for other human diseases including cancer. However, the precise delivery of the genetic cargo to cells and tissues of interest remains challenging. Here, we show an adaptive strategy that enables the docking of different targeting ligands onto the surface of mRNA-loaded small extracellular vesicles (sEVs). This is achieved by using a microfluidic electroporation approach in which a combination of nano- and milli-second pulses produces large amounts of IFN-γ mRNA-loaded sEVs with CD64 overexpressed on their surface. The CD64 molecule serves as an adaptor to dock targeting ligands, such as anti-CD71 and anti-programmed cell death-ligand 1 (PD-L1) antibodies. The resulting immunogenic sEVs (imsEV) preferentially target glioblastoma cells and generate potent antitumour activities in vivo, including against tumours intrinsically resistant to immunotherapy. Together, these results provide an adaptive approach to engineering mRNA-loaded sEVs with targeting functionality and pave the way for their adoption in cancer immunotherapy applications.

Silencing of ATP1A1 attenuates cell membrane disruption by nanosecond electric pulses

This study explored the role of the Na/K-ATPase (NKA) in membrane permeabilization induced by nanosecond electric pulses. Using CRISPR/Cas9 and shRNA, we silenced the ATP1A1 gene, which encodes α1 NKA subunit in U937 human monocytes. Silencing reduced the rate and the cumulative uptake of YoPro-1 dye after electroporation by 300-ns, 7-10 kV/cm pulses, while ouabain, a specific NKA inhibitor, enhanced YoPro-1 entry. We conclude that the α1 subunit supports the electropermeabilized membrane state, by forming or stabilizing electropores or by hindering repair mechanisms, and this role is independent of NKA's ion pump function.

Development of a Transformation System for Nitratireductor sp

Nitratireductor sp. OM-1 can accumulate butenoic acid, which is a short-chain unsaturated carboxylic acid utilized for chemical products. So far, we have predicted the thioesterase gene, te, as a candidate gene for butenoic acid biosynthesis, based on comparative transcriptome analysis. To confirm the function of te, the gene transfer system in Nitratireductor sp. OM-1 was required. Thus, in this study, we used electroporation as a transformation system and pRK415, a broad host range plasmid, and optimized the conditions. As a result, a maximum transformation efficiency of 7.9 × 104 colonies/µg DNA was obtained at 22.5 kV/cm. Moreover, an expression vector, pRK415-te, was constructed by insertion of te, which was successfully transferred into strain OM-1, using electroporation. The recombinant OM-1 strain produced butenoic acid at 26.7 mg/g of dried cell weight, which was a 254% increase compared to transformants harboring an empty vector. This is the first report of a gene transfer system for Nitratireductor sp., which showed that the te gene was responsible for butenoic acid production.

Effective proliferation control of MCF7 breast cancer using microsecond duration electrical pulse

BACKGROUND

Electro-permeablization using a pulse generator is a novel non-invasive approach for cancer therapy. It serves as a cell permeability enhancing agent for cancer treatment.

OBJECTIVE

In this article in vitro investigation of the effect of 1.0 kV/cm, 1.5 kV/cm and 2.0 kV/cm, 50 µs duration pulsed electric field on MCF-7 cell line has been done. Furthermore, combinational therapy of curcumin and electrical pulses has been also investigated.

MATERIAL AND METHOD

A variable voltage (100 V-1200 V, 100 V step) and 50 µs duration pulse generator has been designed, which is further used for the investigation of electroporation and destructive electrical field intensity. Investigation of the effect of electrical pulses on cancer cells has been performed using Trypan Blue Exclusion Test, MTT Assay and Clonogenic Assay.

RESULTS

It has been observed that electrical field intensity of 2 kV/cm, 50 µsec duration, 10 pulses at repetition rate of 1 pulse per second corresponding to total energy of 4 J is more than enough for causing necrotic cell death due to permanent damage of cell membrane of the cancer cell. Also, it has been observed that electrical pulse application enhances curcumin uptake by cells.

CONCLUSION

Electrical pulses can effectively inhibit the cancer cell growth and proliferation. Furthermore, observation shows that electroporation enhances the curcumin uptake, therefore, it can be used for therapeutic purposes.

Highly Efficient Genetic Transformation Methods for the Marine Oleaginous Diatom Fistulifera solaris

The oleaginous diatom Fistulifera solaris is a promising producer of biofuel owing to the high content of the lipids. A genetic transformation technique by microparticle bombardment for this diatom was already established. However, the transformation efficiency was significantly lower than those of other diatoms. Devoting efforts to advance the genetic modifications of this diatom is crucial to unlock its full potential. In this study, we optimized the microparticle bombardment protocol, and newly established a multi-pulse electroporation protocol for this diatom. The nutrient-rich medium in the pre-culture stage played an essential role to increase the transformation efficiency of the bombardment method. On the other hand, use of the nutrient-rich medium in the electroporation experiments resulted in decreasing the efficiency because excess nutrient salts could hamper to establish the best conductivity condition. Adjustments on the number and voltage of the poring pulses were also critical to obtain the best balance between cell viability and efficient pore formation. Under the optimized conditions, the transformation efficiencies of microparticle bombardment and multi-pulse electroporation were 111 and 82 per 108 cells, respectively (37 and 27 times higher than the conventional bombardment method). With the aid of the optimized protocol, we successfully developed the transformant clone over-expressing the endogenous fat storage-inducing transmembrane protein (FIT)-like protein, which was previously found in the genome of the oleaginous diatom F. solaris and the oleaginous eustigmatophyte Nannochloropsis gaditana. This study provides powerful techniques to investigate and further enhance the metabolic functions of F. solaris by genetic engineering.