Applications of plasma-liquid systems : a review

Plasma-liquid systems have attracted increasing attention in recent years, owing to their high potential in material processing and nanoscience, environmental remediation, sterilization, biomedicine, and food applications. Due to the multidisciplinary character of this scientific field and due to its broad range of established and promising applications, an updated overview is required, addressing the various applications of plasma-liquid systems till now. In the present review, after a brief historical introduction on this important research field, the authors aimed to bring together a wide range of applications of plasma-liquid systems, including nanomaterial processing, water analytical chemistry, water purification, plasma sterilization, plasma medicine, food preservation and agricultural processing, power transformers for high voltage switching, and polymer solution treatment. Although the general understanding of plasma-liquid interactions and their applications has grown significantly in recent decades, it is aimed here to give an updated overview on the possible applications of plasma-liquid systems. This review can be used as a guide for researchers from different fields to gain insight in the history and state-of-the-art of plasma-liquid interactions and to obtain an overview on the acquired knowledge in this field up to now

Influences on the Emissions of Bacterial Plasmas Generated through Nanosecond Laser-Induced Breakdown Spectroscopy

In the past decade, laser-induced breakdown spectroscopy has been shown to provide compositional data that can be used for discrimination between bacterial specimens at the strain level. This work demonstrates the viability of this technique in a clinical setting. Studies were conducted to investigate the impact of emissions generated by a nitrocellulose filter paper background on the classification of four species: E. coli, S. epidermidis, M. smegmatis, and P. aeruginosa. Limits of detection were determined as 48±12 kCFU per ablation event for new mounting procedures using standard diagnostic laboratory techniques, and a device for centrifuge filtration was designed for sampling from low-titer bacterial suspensions. Plasma emissions from samples grown at biological levels of magnesium, zinc, and glucose were shown not to deviate from controls. A limit of detection for environmental zinc was found to be 11 ppm. Discrimination with heat-killed samples was demonstrated, providing a sterile diagnostic environment

The role of semaphorins in response to injury in C. elegans neurons

When neural tissue is injured by trauma, delicate neuronal processes such as axons and dendrites are prone to lesion damage and often disconnect. The molecular, cellular, and circuit mechanisms that underlie the regrowth and reconnection of these processes and the recovery of behavior are major challenges in the fields of neuroscience, regeneration, and resilience. At the molecular and cellular levels, signaling pathways that mediate neuronal growth cone guidance during development can play a role in neuronal regeneration and recovery from injury. One family of signaling proteins involved in this process comprises the highly conserved semaphorins and their receptors, the plexins. Across various species, from C. elegans to humans, semaphorins and plexins are crucial for axon pathfinding and synapse formation during development. In the mammalian nervous system, the semaphorin signaling system is comprised of more than 20 semaphorins and 9 plexins, whereas the C. elegans genome only encodes 3 semaphorins and 2 plexin receptors. Among them, the transmembrane semaphorins, SMP-1 and SMP-2, signal through their receptor PLX-1, while the secreted semaphorin MAB-20, signals through PLX-2. This dissertation explores the role of semaphorin signaling in neuroregeneration in vivo, by making use of the experimental advantages of Caenorhabditis elegans. Importantly, this versatile model animal has the natural ability to regenerate neuronal processes after injury and optic methods were developed to precisely disconnect single neurites in otherwise intact animals using laser microsurgery. Moreover, the semaphorin system is relatively simple and genetically amenable, and transgenic, microscopy and behavior analysis methods are well established. The development and assessment of a new laser microsurgery system as part of this thesis allowed reliable and accurate disconnection of identifiable axons and dendrites. The elucidated expression patterns and involvement of C. elegans semaphorins in neural regeneration have shed significant light with regard to the role this pathway plays in C. elegans regeneration and added to the field of knowledge of neural regeneration research. The findings reveal that regrowth and reconnection are more prevalent in the absence of both plexin receptors and the secreted semaphorin MAB-20. This suggests that the semaphorin signaling in this system restricts neural growth, possibly to prevent aberrant reconnection. The membrane-bound SMP-1 and SMP-2 might have a redundant role, signaling through PLX-1. These results align with the inhibitory effects of semaphorin signaling on axonal growth and guidance during development in the mammalian system. Therefore, secreted and membrane-bound semaphorin signaling pathways restrict regeneration using distinct processes, likely involving spatial specificity and recurrent signals. Findings such as the ones presented in this thesis delve deeper into the mechanisms and factors involved in promoting regeneration and aid to uncover valuable insights that could assist in overcoming the challenges faced by regenerative medicine in treating central nervous system injuries and disorders

Highly efficient cash sterilization with ultrafast and flexible Joule‐heating strategy by laser patterning

Since ancient times, humans have learned to use fire and other heating methods to fight against dangerous pathogens, like cooking raw food, sterilizing surgical tools, and disinfecting other pathogen transmission media. However, it remains difficult for current heating methods to achieve extremely fast and highly efficient sterilization simultaneously. Herein, an ultrafast and uniform heating‐based strategy with outstanding bactericidal performance is proposed. Ultra‐precise laser manufacturing is used to fabricate the Joule heater which can be rapidly heated to 90 °C in 5 s with less than 1 °C fluctuation in a large area by real‐time temperature feedback control. An over 98% bactericidal efficiency on S. aureus for 30 s and on E. coli for merely 5 s is shown. The heating strategy shows a 360 times faster acceleration compared to the commonly used steam sterilization from the suggested guidelines by the Centers for Disease Control and Prevention (CDC), indicating that high temperatures with short duration can effectively disinfect microorganisms. As a proof of concept, this heating strategy can be widely applied to sterilizing cash and various objects to help protect the public from bacteria in daily life

Development of Laser-Induced Breakdown Spectroscopy as a Rapid Diagnostic Tool for Bacterial Infection

A rapid elemental analysis technique known as laser-induced breakdown spectroscopy (LIBS) has been shown to be a promising tool for detection and identification of pathogens. The aim of this work was to demonstrate the feasibility of the LIBS technique as a point-of-care diagnostic tool for bacterial infection. A size-based technique for separating bacteria from unwanted material that could be present in a clinical specimen was developed using a custom-built centrifuge tube insert device. Tungsten powder was used to simulate unwanted contaminants in a bacterial suspension, all of which was removed from suspension while 90% of the bacteria were successfully separated from the contaminant. A new bacterial mounting procedure was developed by designing and constructing a small aluminum cone for use with the centrifuge tube insert. The bacterial limit of detection for this new mounting procedure was calculated to be 5000 CFU per laser shot location – an order of magnitude improvement from previous mounting procedures. Methods to reduce the measured shot-to-shot variation assumed to be caused by uneven deposition of the bacteria using either the detergent Tween 20 or growth of bacteria in a liquid culture medium were investigated. No significant effect was observed. The ability to detect bacteria that were collected using common pathology swabs to more closely simulate the collection of some clinical specimens was also investigated. The efficiency of bacterial cell pick-up with a swab and subsequent shake-off prior to LIBS testing was determined. Protocols for collecting bacteria from swabs were developed and a study of the resulting LIBS emission as a function of bacterial coverage was conducted using the new mounting procedure

Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts against COVID 19

Silver has been an influential segment of pharmaceutical utilization for remedies & hygiene in the latest era. The first topic reviews the study on air sanitization ventilation & air sanitizer systems using laser ablated silver nanoparticles (inspired by 2020 Pandemic) directing to contamination of deadly biological particles. Intention of this investigation is to validate possible antiviral silver nanoparticles construction to be distributed by retention, to abate the aggravation of breathing organs flu. The underlying description of investigation consists of bibliometric reasoning of the review of the outcome of silver nanoparticles on the sterilization of viral ailments. The investigation will deliberate the approach of use of laser ablated silver nanoparticles for anti-actions. The chapter outcomes in the fascinating utilization of silver nanoparticles for pharmaceutical purposes for contagious diseases, viruses or bacteria and devotes to the upgradation of therapeutic education to safeguard health care workers from threatening viruses at therapeutic organizations. Morally, the investigation will obtain a hygienic scheme, which might be installed at every communal or individual places cost-effectively including silver nanoparticles (because of their therapeutic properties). The second section of investigation considers distinct techniques for manufacturing silver nanoparticles. The various schemes have been compared based on their pros & cons. The method of laser ablation for generating nanoparticles underwater is briefed. The intention of this part is to disclose the current & anticipation probabilities of the process - laser ablation, as a profitable and eco-favorable innovation for manufacturing silver nanoparticle in liquid solutions. The chapter is motivated by two of our reviewed papers i.e., “Antibacterial and anti-viral effects of silver nanoparticles in medicine against covid 19” and “Methods for obtaining silver nanoparticles”

Silver-Based Antimicrobials

There is some talk about an antibiotic Armageddon due to quickly developing resistance towards commercially available antibiotics. For the most part, the classical antibiotic pipeline has dried up, and antibiotic resistance to any new drugs quickly develops. It is here that metal-based antimicrobials can step forward as possible solutions in this antimicrobial resistance era. The biological targets of metal atoms are more diverse, thus making it more difficult for bacteria to develop resistance compared with classical antibiotics. The metal silver has been used since antiquity for wound healing and water purification. At present, it is the most prevalent antimicrobial metal used in healthcare, industry, and consumer products. Silver is being used in the form of ionic salt, colloids, or in specific nanomaterials, and as described in this book, it can be applied as mixtures with other antimicrobials or coating composites. The different formulations are explored for their efficacy against a variety of problems related to agricultural and medical infections. Whilst by no means exhaustive, this book nicely highlights the present directions in silver-based antimicrobial research and antimicrobial formulation development. The chapters have been organized from a general introductory review to approaches of mixing other antimicrobials and materials to enhance silver performance. This is followed by synthetic approaches. First are biogenic (sometimes called green or eco-friendly) approaches, followed by advanced physical–chemical synthetic approaches. The book ends with an overview of applications through a review of patents over the past 10 years

Surface treatments to modulate bioadhesion: A critical review

On account of the recent increase in importance of biological and microbiological adhesion in industries such as healthcare and food manufacturing many researchers are now turning to the study of materials, wettability and adhesion to develop the technology within these industries further. This is highly significant as the stem cell industry alone, for example, is currently worth £3.5 million in the United Kingdom (UK) alone. This paper reviews the current state-of-the-art techniques used for surface treatment with regards to modulating biological adhesion including laser surface treatment, plasma treatment, micro/nano printing and lithography, specifically highlighting areas of interest for further consideration by the scientific community. What is more, this review discusses the advantages and disadvantages of the current techniques enabling the assessment of the most attractive means for modulating biological adhesion, taking in to account cost effectiveness, complexity of equipment and capabilities for processing and analysis

Plasma chemical driven biomedical applications with a radio frequency driven atmospheric pressure plasma jet

2012 Fall.Includes bibliographical references.We present radio frequency driven atmospheric pressure plasma jet for various biomedical applications such as tissue removal, bacterial sterilization, and tooth whitening. Two different types of plasma assisted electrosurgery, remote electrode plasma jet and plasma jet surrounding monopolar electrosurgical electrode, were employed to enhance tissue removal in terms of less heat damage on contiguous tissue and fast removal rate. Chlorine based chemical (CHxClx) additives in argon plasma jet enhanced tissue removal rate, proportional to the Cl radical density in the plasma jet. Pulsed RF provided another knob to control the removal profile, heat damage, and removal rate. Hydrogen peroxide (H2O2) additive provided abundant OH generation in the helium plasma jet. It not only enhanced tissue removal rate but also reduced heat damage on the contiguous tissue. The tissue removal mechanism of helium-H2O2 plasma is explained based on the FTIR measurement of the tissue samples, and optical emission and absorption spectra. Hydrogen peroxide addition to argon plasma jet was employed for bacterial inactivation. Observed OH density by optical emission and absorption was proportional to the number of deactivated microorganism. Argon plasma jet in DI water also provided abundant OH on the interface of water and gas plasma. The OH radicals applied on porcine tooth sample selectively removed the stain without damaging the underlying enamel

Design and Characterization of Paper-based Plasma Generators for Sterilization

Nowadays, proper sterilization of surfaces, objects, and even ourselves is a constant need. This work describes the fabrication and thorough characterization of simplistic and disposable plasma-based generators for microbial disinfection, made from metalized paper with aluminum in reference to a previous design developed by Mazzeo et al. These devices rely on the working principle of the dielectric barrier discharge and the generation of plasma was carried out inside a vacuum chamber where different atmospheres were tested. The experimental results demonstrated that additional layers of materials with higher resistance to corrosion and oxidation than aluminum brought no improvements or advantages to reduce the surface degradation by plasmas. These paper-based plasma generators' optical emission spectra indicated that many reactive species desirable in applications such as biological decontamination are produced in the glow discharge. On another note, these generators achieved tolerable biological temperatures (T<40 ºC), representing an excellent approach to the generation of non-thermal plasmas (T<70 ºC). Beyond their characterization, this thesis demonstrated these devices' ability to generate plasma on a reduced scale and a possible optimization method of the decontamination process through plasma confinement. Towards these paper-based generators' stability, they were capable of generating plasma that lasted for more than one hour.Hoje em dia, a esterilização adequada de superfícies, objetos, e mesmo de nós próprios é uma necessidade constante. Este trabalho descreve o fabrico e caracterização minuciosa de geradores de plasma simplistas e descartáveis, para a desinfeção microbiana, feitos de papel metalizado com alumínio em referência a um design previamente desenvolvido por Mazzeo et al. Estes dispositivos baseiam-se no princípio de funcionamento da descarga da barreira dielétrica e a geração de plasma foi realizada dentro de uma câmara de vácuo, onde foram testadas diferentes atmosferas. Os resultados experimentais demonstraram que as camadas adicionais de materiais com maior resistência à corrosão e oxidação do que o alumínio não trouxeram melhorias ou vantagens na redução da degradação da superfície pelo plasma. Os espectros de emissão ótica destes geradores indicaram que muitas das espécies reativas desejáveis em aplicações tais como a descontaminação biológica são produzidas na descarga luminescente. Por outro lado, estes geradores alcançaram temperaturas biológicas toleráveis (T<40 ºC), representando uma excelente abordagem à geração de plasmas não térmicos (T<70 ºC). Para além da caracterização destes geradores, esta tese demonstrou a capacidade destes dispositivos de gerar plasma a uma escala reduzida e um possível método de otimização do processo de descontaminação através do confinamento do plasma. Relativamente à estabilidade destes geradores de plasma em papel, estes foram capazes de gerar plasma com uma durabilidade superior a uma hora