Alkaline Plasma-Activated Water (PAW) as an Innovative Therapeutic Avenue for Cancer Treatment

Plasma-activated water (PAW) is considered to be an effective anticancer agent due to the diverse aqueous reactive oxygen and nitrogen species (RONS: ROS and RNS), but the drawback of low dose and short duration of RONS in acidified PAW limits their clinical application. Herein, this Letter presents an innovative therapeutic avenue for cancer treatment with highly-effective alkaline PAW prepared by air surface plasma. This anticancer alkaline formulation is comprised of a rich mixture of highly chemical RONS and exhibited a prolonged half-life compared to acidified PAW. The H2O2, NO2-, and ONOO-/O2- concentrations in the alkaline PAW can reach up to 18-, 16-, and 14-fold higher than that in acidic PAW, and the half-life of these species was extended over 8-, 10-, and 26-fold, respectively. The synergistic potent redox action between these RONS with alkaline pH was shown to be more potent than acidic PAW for cancer cell inhibition in vitro. Furthermore, the alkaline PAW injection treatment also significantly inhibited tumor growth in tumor-bearing mice. The possible reasons are that the alkaline PAW would disturb the acid extracellular milieu leading to the inhibition of tumor growth and progression; moreover, the efficient and durable RONS with alkaline pH could induce significant cell apoptosis by altering cell biomolecules and participating apoptosis-related signaling pathways. These findings offer promising applications for developing a strategy with real potential for tumor treatment in clinical applications

Facile synthesis of high-performance indium nanocrystals for selective CO2-to-formate electroreduction

Selective electrocatalytic reduction of CO2 to formate has received increasing interest for CO2 conversion and utilization. Yet, the CO2 reduction process still faces major challenges, partly due to the lack of cost-effective, highly active, selective and stable electrocatalysts. Here, we report a mesoporous indium (mp-In) electrocatalyst composed of nanobelts synthesized via a simple solution-based approach for selective CO2 reduction to formate. The mp-In nanocrystals provide enlarged surface areas, abundant surface active sites and edge/low-coordinated sites. Such advantages afford the mp-In with an outstanding electrocatalytic performance for the CO2-to-formate conversion. A high formate selectivity, with a Faradaic efficiency (FE) of >90% was achieved over a potential of −0.95 V to −1.1 V (vs VRHE). The mp-In catalyst showed excellent durability, reflected by the stable formate selectivity and current density over a 24 h reaction period. Density functional theory (DFT) calculations reveal that the stabilization of the intermediate OCHO* on the In-plane surfaces is energetically feasible, further elucidating the origin of its enhanced CO2-to-formate activity and selectivity. This work may offer valuable insights for the facile fabrication of porous hierarchical nanostructures for electrocatalytic and selective reduction of CO2.</p

Plasma-Assisted Sustainable Nitrogen-to-Ammonia Fixation: Mixed-phase, Synergistic Processes and Mechanisms.

Ammonia plays a crucial role in industry and agriculture worldwide, but traditional industrial ammonia production methods are energy-intensive and negatively impact the environment. Ammonia synthesis using low-temperature plasma technology has gained traction in the pursuit of environment-benign and cost-effective methods for producing green ammonia. This Review discusses the recent advances in low-temperature plasma-assisted ammonia synthesis, focusing on three main routes: N2 +H2 plasma-only, N2 +H2 O plasma-only, and plasma coupled with other technologies. The reaction pathways involved in the plasma-assisted ammonia synthesis, as well as the process parameters, including the optimum catalyst types and discharge schemes, are examined. Building upon the current research status, the challenges and research opportunities in the plasma-assisted ammonia synthesis processes are outlined. The article concludes with the outlook for the future development of the plasma-assisted ammonia synthesis technology in real-life industrial applications

Direct and indirect activation of biological objects using cold atmospheric plasma

This project was a step forward in the development and application of chemically reactive physical plasmas for direct and indirect treatment of biological objects. The project unravelled the link between plasma-generated chemistry and resultant bioactivity, so as to improve the cold plasma devices for specific applications. The project investigated the interactions of cold plasmas with biological objects including plant seeds, living cells and microorganisms, to provide some theoretical and experimental bases for the development of plasma applications

Atmospheric-pressure plasma treated water for seed germination and seedling growth of mung bean and its sterilization effect on mung bean sprouts

Plasma treated water (PTW), produced by atmospheric-pressure plasma treatment of water, usually contains various reactive oxygen and nitrogen species (RONS). This study aimed at evaluating the effectiveness of different types of PTW on seed germination, seedling growth and microbial sterilization during the germinated mung bean processing. Results showed that air-PTW possessed outstanding abilities in improving seed germination and seedling growth with a germination index of 95.50% and a vigor index of 1146.64, and in microbial decontamination. The physicochemical properties of the PTW were analyzed to better understand the PTW stressed germination. Some physiological parameters like the activity of superoxide dismutase (SOD), the contents of malondialdehyde (MDA) and phytohormone (indole acetic acid (IAA) and abscisic acid (ABA)) during germination were also evaluated. This study suggested that air-PTW treatment could indeed provide a green and effective mean of stimulating seed germination and plant growth, and thus accelerate the growth cycle. Industrial relevance Increasing the production of food by using both economical and environmentally friendly means has been deemed as an urgent matter to sustain the food demand of rapidly growing world population. The results of this study suggest that PTW presents a great opportunity to address this need by increasing seedling growth and viability. PTW treatment is an environment-friendly and low-cost mean of stimulating seed germination and plant growth, which possesses the potential of scale up or industrial applications in relevant fields

Continuous flow removal of acid fuchsine by dielectric barrier discharge plasma water bed enhanced by activated carbon adsorption

Continuous processes which allow for large amount of wastewater to be treated to meet drainage standards while reducing treatment time and energy consumption are urgently needed. In this study, a dielectric barrier discharge plasma water bed system was designed and then coupled with granular activated carbon (GAC) adsorption to rapidly remove acid fuchsine (AF) with high efficiency. Effects of feeding gases, treatment time and initial concentration of AF on removal efficiency were investigated. Results showed that compared to the N2 and air plasmas treatments, O2 plasma processing was most effective for AF degradation due to the strong oxidation ability of generated activated species, especially the OH radicals. The addition of GAC significantly enhanced the removal efficiency of AF in aqueous solution and shorten the required time by 50%. The effect was attributed to the ability of porous carbon to trap and concentrate the dye, increasing the time dye molecules were exposed to the plasma discharge zone, and to enhance the production of OH radicals on/in GAC to boost the degradation of dyes by plasma as well as in situ regenerate the exhausted GAC. The study offers a new opportunity for continuous effective remediation of wastewater contaminated with organic dyes using plasma technologies. [Figure not available: see fulltext.].</p

Design and characteristics investigation of a miniature low-temperature plasma spark discharge device

Atmospheric pressure low-temperature plasma is a promising tool in biomedicine applications including blood coagulation, bacterial inactivation, sterilization, and cancer treatment, due to its high chemical activity and limited thermal damage. It is of great importance to develop portable plasma sources that are safe to human touch and suitable for outdoor and household operation. In this work, a portable and rechargeable low-temperature plasma spark discharge device (130 mm × 80 mm × 35 mm, 300 g) was designed. The discharge frequency and plume length were optimized by the selection of resistance, capacitance, electrode gap, and ground electrode aperture. Results show that the spark plasma plume is generated with a length of 12 mm and a frequency of 10 Hz at a capacitance of 0.33 μF, resistance of 1 MΩ, electrode gap of 2 mm, and ground electrode aperture of 1.5 mm. Biological tests indicate that the plasma produced by this device contains abundant reactive species, which can be applied in plasma biomedicine, including daily sterilization and wound healing

Linear-field plasma jet arrays excited by high-voltage alternating current and nanosecond pulses

Atmospheric pressure plasma jet arrays can expand the treatment dimension of a single jet to large scales effectively, and the arrays with a good downstream uniformity have a great potential for applications in the materials surface treatment and biomedicine. In this paper, a linear-field jet array with a ring-ring electrode structure in Ar is excited by alternating current (AC) and nanosecond (ns) pulse voltage, and the characteristics and downstream uniformity of the array and their dependence on the applied voltage and gas flow rate are investigated and compared through optical, electrical, and Schlieren diagnosis. The electrical and hydrodynamic interactions between the jets in the array are analyzed and discussed. The results show that the ns pulse excited jet arrays can generate relatively large-scale plasma with better uniformity, longer plumes, and higher intensity active species with a higher energy efficiency than the AC excited ones. No visible deviation of the plume and gas flow trajectories in the light emission and Schlieren images is observed for the ns pulse excited arrays. On the other hand, deviation of plume trajectories is shown to depend on the applied voltage and the gas flow rate for the AC excited arrays. The shorter duration of the interaction of the ns pulse excited jet arrays compared with that of the AC excited jet arrays results in the weaker effects of the Coulomb repellence force and the gas heating, which helps to maintain the uniformity of jet arrays. The reported results can help to design controllable and scalable plasma jet arrays in the economic Ar with good uniformity and higher energy efficiency for material surface and biomedical treatments

Cosmetic reconstruction in breast cancer patients: Opportunities for nanocomposite materials

The most common malignancy in women, breast cancer remains a major medical challenge that affects the life of thousands of patients every year. With recognized benefits to body image and self-esteem, the use of synthetic mammary implants for elective cosmetic augmentation and post-mastectomy reconstruction continues to increase. Higher breast implant use leads to an increased occurrence of implant-related complications associated with implant leakage and rupture, capsular contracture, necrosis and infections, which include delayed healing, pain, poor aesthetic outcomes and the need for revision surgeries. Along with the health status of the implant recipient and the skill of the surgeon, the properties of the implant determine the likelihood of implant-related complications and, in doing so, specific patient outcomes. This paper will review the challenges associated with the use of silicone, saline and “gummy bear” implants in view of their application in patients recovering from breast cancer-related mastectomy, and investigate the opportunities presented by advanced functional nanomaterials in meeting these challenges and potentially opening new dimensions for breast reconstruction. Statement of Significance Breast cancer is a significant cause of morbidity and mortality in women worldwide, which is difficult to prevent or predict, and its treatment carries long-term physiological and psychological consequences. Post-mastectomy breast reconstruction addresses the cosmetic aspect of cancer treatment. Yet, drawbacks of current implants contribute to the development of implant-associated complications, which may lead to prolonged patient care, pain and loss of function. Nanomaterials can help resolve the intrinsic biomechanical mismatch between implant and tissues, enhance mechanical properties of soft implantable materials, and provide an alternative avenue for controlled drug delivery. Here, we explore advances in the use of functionalized nanomaterials to enhance the properties of breast implants, with representative examples that highlight the utility of nanomaterials in addressing key challenges associated with breast reconstruction