Enhancing single-cell bioconversion efficiency by harnessing nanosecond pulsed electric field processing

Low-Intensity Nanosecond Pulsed Electric Field Accelerates Osteogenic Transformation of Human Dermal Fibroblasts by Enhancing Cell Pluripotency

Autologous human fibroblasts have the potential to differentiate into the osteogenic lineage under specific conditions and can be utilized for bone regeneration. However, their efficiency is currently unsatisfactory. Recently, low-intensity nanosecond pulsed electric field (nsPEF) stimulation has been demonstrated to enhance cell pluripotency by activating epigenetic regulatory pathways. In this study, human dermal fibroblasts were exposed to different intensities of nsPEF to assess whether these exposures resulted in changes in proliferation rate, calcium salt deposition, and expression of differentiation-related markers in different experimental groups. The results showed a significant increase in cell proliferation, pluripotency, bone marker expression, and osteogenic differentiation efficiency when stimulating cells with 5 kV/cm of nsPEF. However, cell proliferation and differentiation significantly decreased at 25 kV/cm. Additionally, the proliferation and efficiency of osteogenic differentiation were reduced when the nsPEF intensity was increased to 50 kV/cm. Treatment with a 5 kV/cm of nsPEF led to increased and concentrated expression of Yes-Associated Protein (YAP) in the nucleus. These observations suggest that human dermal fibroblasts possess a heightened potential to differentiate into osteogenic cells when activated with nsPEF at 5 kV/cm. Consequently, the nsPEF strengthening strategy shows promise for fibroblast-based tissue-engineered bone repair research.

Effect of nanosecond pulsed electric fields (nsPEFs) on coronavirus survival

Previous work demonstrated inactivation of influenza virus by GHz frequency electromagnetic fields. Despite theoretical and experimental results, the underlying mechanism driving this inactivation remains unknown. One hypothesis is that the electromagnetic field is causing damage to the virion membrane (and therefore changing spike protein orientation) rendering the virus unable to attach and infect host cells. Towards examining this hypothesis, our group employed nanosecond pulsed electric fields (nsPEFs) as a surrogate to radiofrequency (RF) exposure to enable exploration of dose response thresholds of electric field-induced viral membrane damage. In summary, Bovine coronavirus (BCoV) was exposed, in suspension, to mono and bipolar 600-ns pulsed electric fields (nsPEFs) at two amplitudes (12.5 and 25 kV/cm) and pulse numbers [0 (sham), 1, 5, 10, 100, and 1000] at a 1 Hz (Hz) repetition rate. The temperature rise immediately after exposure(s) was measured using thermocouples to differentiate effects of the electric field (E-field) and heating (i.e., the thermal gradient). Inactivation of BCoV was evaluated by infecting HRT-18G host cells and assessing differences in virus infectivity days after exposure. Our results show that 600 nsPEFs, both bipolar and monopolar, can reduce the infectivity of coronaviruses at various amplitudes, pulse numbers, and pulse polarity. Interestingly, we observed that bipolar exposures appeared to be more efficient at lower exposure intensities than monopolar pulses. Future work should focus on experiments to identify the mechanism underlying nsPEF-induced viral inactivation.

Effect of ultrasound on Pseudoneochloris marina and Chlorella zofingiensis growth

The present work evaluated the ultrasound (US) effects on the growth of Pseudoneochloris marina and Chlorella zofingiensis. For P. marina, US treatment did not increase cell proliferation and reduced cell density when used for 60 min (exponential phase, for 5 days), indicating a possible occurrence of cell damage. For C. zofingiensis, the application of discontinuous US for 10 min resulted in an increase of 65 % in biomass concentration compared to the control. These distinct behaviors indicate that microalgae species react differently to physical stimuli. After US treatment, a reduction of carotenoid, chlorophyll, lipid and protein concentrations was observed, which may be related to changes in the metabolic pathways to produce these compounds. Overall, the results of the present study show the potential of discontinuous US to enhance microalgae cell proliferation.

Nanosecond Pulsed Electric Field Induces an Antitumor Effect in Triple-Negative Breast Cancer via CXCL9 Axis Dependence in Mice

Triple-negative breast cancer (TNBC) is a refractory tumor, and therapeutic options are very limited. Local ablation has been applied recently. Chemokines play a critical role in the recruitment of immune cells into ablative tumors. Nanosecond pulsed electric field (nsPEF) shows potential anti-tumor efficacy, but the mechanism for maintaining the immune effect is not very clear. Here, we applied nsPEF for treating 4T1 breast cancer cells in vitro. RNA sequencing (RNA-seq) was applied. Anti-CXCL9 was used alone or combined with nsPEF to treat triple-negative breast cancer in mice. We demonstrated that nsPEF effectively induced cell apoptosis and inhibited the growth and metastasis of triple-negative breast cancer. An immune effect, especially chemotaxis, was activated by nsPEF. The number of infiltrated CD8+ T cells was increased significantly. We found that the inhibition of residual breast cancer growth by nsPEF was dependent on the CXCL9 axis. In conclusion, our work demonstrated that nsPEF effectively ablated the tumor, aroused an immune response, and inhibited residual breast cancer growth via CXCL9 axis dependence in mice.