Abstract:For the past twelve years, cold plasmas (i.e., weakly ionized gas) have been positioned as a breakthrough technology for treating cancer thanks to their antitumor properties. The innovation of ad hoc plasma sources and personalized protocols appears crucial to treat cancers with a very poor prognosis. This is the case for cholangiocarcinoma (CCA), a biliary tract cancer, whose treatment with cold plasma is envisioned but requires the innovation of catheters and endoscopic devices for local therapies. Before co… Show more
“…In outlook, it is important to underline that this experimental study can have interesting spinoffs for applied research, particularly regarding the engineering of plasma medical devices. For example, in one of our previous papers, we developed a transferred plasma catheter that allows endoscopic treatment of the biliary tree of porcine models [37] . This type of catheter, supplied by helium and powered by high-voltage pulses, has a floating electrode (long metallic wire) that endoscopically transfers cold plasma to the area to be treated (human tissue, cells, …).…”
In this work, a jet of cold plasma is generated in a device supplied in helium and powered with a high-voltage nanopulse power supply, hence generating guided streamers. We focus on the interaction between these guided streamers and two targets placed in a series: a metal mesh target (MM) at floating potential followed by a metal plate target (MP) grounded by a 1500 Ω resistor. We demonstrate that such an experimental setup allows to shift from a physics of streamer repeatability to a physics of streamer self-organization, i.e., from the repetition of guided streamers that exhibit fixed spatiotemporal constants to the emergence of self-organized guided streamers, each of which is generated on the rising edge of a high-voltage pulse. Up to five positive guided streamers can be self-organized one after the other, all distinct in space and time. While self-organization occurs in the capillary and up to the MM target, we also demonstrate the existence of transient emissive phenomena in the inter-target region, especially a filamentary discharge whose generation is directly correlated with complexity order Ω. The mechanisms of the self-organized guided streamers are deciphered by correlating their optical and electrical properties measured by fast ICCD camera and current-voltage probes, respectively. For the sake of clarity, special attention is paid to the case where three self-organized guided streamers (α, β and γ) propagate at vα = 75.7 km·s–1, vβ = 66.5 km·s–1 and vγ = 58.2 km·s–1), before being accelerated in the vicinity of the MM target.
“…In outlook, it is important to underline that this experimental study can have interesting spinoffs for applied research, particularly regarding the engineering of plasma medical devices. For example, in one of our previous papers, we developed a transferred plasma catheter that allows endoscopic treatment of the biliary tree of porcine models [37] . This type of catheter, supplied by helium and powered by high-voltage pulses, has a floating electrode (long metallic wire) that endoscopically transfers cold plasma to the area to be treated (human tissue, cells, …).…”
In this work, a jet of cold plasma is generated in a device supplied in helium and powered with a high-voltage nanopulse power supply, hence generating guided streamers. We focus on the interaction between these guided streamers and two targets placed in a series: a metal mesh target (MM) at floating potential followed by a metal plate target (MP) grounded by a 1500 Ω resistor. We demonstrate that such an experimental setup allows to shift from a physics of streamer repeatability to a physics of streamer self-organization, i.e., from the repetition of guided streamers that exhibit fixed spatiotemporal constants to the emergence of self-organized guided streamers, each of which is generated on the rising edge of a high-voltage pulse. Up to five positive guided streamers can be self-organized one after the other, all distinct in space and time. While self-organization occurs in the capillary and up to the MM target, we also demonstrate the existence of transient emissive phenomena in the inter-target region, especially a filamentary discharge whose generation is directly correlated with complexity order Ω. The mechanisms of the self-organized guided streamers are deciphered by correlating their optical and electrical properties measured by fast ICCD camera and current-voltage probes, respectively. For the sake of clarity, special attention is paid to the case where three self-organized guided streamers (α, β and γ) propagate at vα = 75.7 km·s–1, vβ = 66.5 km·s–1 and vγ = 58.2 km·s–1), before being accelerated in the vicinity of the MM target.
“…The noble gases helium and argon in their pristine state or as mixtures with other gases such as nitrogen or oxygen are usually employed as working gases. Plasma jets can be used to treat surface areas as well as deeper tissue layers and visceral cavities ( 13 ). Figure 1 CPP is generated by adding energy to a neutral gas to yield a partially ionized gas that can be operated at or below body temperature (<40°C).…”
Section: Cold Physical Plasma: Devices For Experimental and Clinical ...mentioning
Cold physical plasma (CPP) technology is of high promise for various medical applications.
The interplay of specific components of physical plasma with living cells, tissues and organs on a structural and functional level is of paramount interest with the aim to induce therapeutic effects in a controlled and replicable fashion.
In contrast to other medical disciplines such as dermatology and oromaxillofacial surgery, research reports on CPP application in orthopaedics are scarce.
The present implementation of CPP in orthopaedics involves surface modifications of orthopaedic materials and biomaterials to optimize osseointegration. In addition, the influence of CPP on musculoskeletal cells and tissues is a focus of research, including possible adverse reactions and side effects. Its bactericidal aspects make CPP an attractive supplement to current treatment regimens in case of microbial inflammations such as periprosthetic joint infections. Attributed anticancerogenic and pro-apoptotic effects underline the clinical relevance of CPP as an additive in treating malignant bone lesions.
The present review outlines ongoing research in orthopaedics involving CPP; it distinguishes considerations for safe application and the need for more evidence-based research to facilitate robust clinical implementation.
“…In the capillary, the copper wire lies at the center of a coaxial configuration, surrounded by helium (partly ionized). This arrangement can be electrically assimilated to a transmission line [24,51] typically used in cables (e.g., coaxial cables) designed to conduct high-frequency alternating current [52,53]. A transmission line is generally modelled as a two-port distributed-element circuit designed to conduct an alternating current.…”
Section: Accepted Manuscriptmentioning
confidence: 99%
“…To conclude, the electrical equivalent of a long plasma source suitable for endoscopy described here could take us one step closer to the therapeutic use of CAP in hospitals. More specifically, cholangiocarcinoma in biliary ducts [51], pancreas or colon cancer [20], and lung cancer [61,62] could be treated with a synergistic treatment involving cold plasma. During endoscopic procedures, it could also be used to promote coagulation when bleeding occurs, as CAP coagulates anti-coagulated blood in a few minutes [63,64].…”
Cold atmospheric plasmas are a known source of reactive species enabling various treatments, from the healing of chronic wounds to the treatment of surface cancers. Therapeutic endoscopic procedures require developing specific flexible tools that can be used through or alongside endoscopes. Plasma devices for endoscopy have aroused significant research interest over the past few decades, but their electrical behaviour is not yet fully understood and predictable. There is thus a clear need for a robust model that provides a way to understand and optimize future devices. In this work, for the first time, an electrical equivalent model of a long plasma source (comprising plasma generation, transport and target interaction) was designed, implemented, and validated. System parameters were estimated based on the system geometry and independent measurements. The model reliably reproduces the double ignition (in the quartz chamber and at the treatment site) observed experimentally. Simulations globally agree with measurements taken for various gas gap distances and input voltages. Internal parameters that are difficult to measure, such as the electrical charge at the gas gaps, were inferred. The model can predict leakage current in the body and current at the target site. This work provides a new understanding of endoscopic plasma systems that could be used in the future to ensure patient and operator safety.
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