E Eva Stoffels-Adamowicz

Effects of plasma treatment on wounds

Cold plasma treatment of wounds is gaining much interest, because it will offer a non-contact, painless and harmless therapy to manage large-area lesions (burn wounds, chronic ulcerations). One of the important issues in plasma wound healing is the safety of the method. In this work we study in vitro the effects of plasma treatment on cell death, proliferation and wound healing. Many methods have been developed to study the cell viability and proliferation, but one of the most appreciated ones is the MTT Assay. There are many advantages of using this method such as: the method is safe, fast and convenient, and allows simultaneous analysis of many samples (e.g. cell samples prepared in 96 well plates). Viable cells transform the added MTT tetrazolium salt into purple formazan, which is detected by colorimetric methods. The amonut of viable cells is proportional to the amount of formazan. We performed a parametric study of plasmatreated 3T3 fibroblast cells. For the treatment, a cold atmospheric plasma needle (13.56 MHz micro-jet in helium) was used. The influence of plasma on cell viability was measured using the MTT assay. We observed the long-term effects of plasma on cell viability, dependent on the dosage of plasma treatment. Under high doses cell suffered damage that led to decreased viability. Cell death by apoptosis and necrosis was considered.

Trapping and Processing of Dust Particles in a Low-Pressure Discharge

Publisher Summary This chapter discusses the formation, behavior, and modification of dust particles in a low-pressure plasma. Coulomb interactions of negatively charged particles together with other forces in the plasma result in efficient trapping. A single particle can be kept motionless in the plasma, and fully controlled by the experimentalist. This chapter determines the particle properties by angle-resolved Mie scattering, and modifies them by etching or deposition in the plasma. In addition, it is shown that a low-pressure discharge is well suitable for production or surface modification of special dust particles.

Formation of particle conglomerates in a methane discharge

Publisher Summary This chapter examines particle nucleation and growth in a low-pressure radio-frequency discharge in methane (CH4). Nanometer size particle precursors are formed during irradiation of the plasma by a high-power laser. Laser-produced particles acquire negative charge and remain trapped in the plasma, where particle growth and coalescence takes place. As a result of coalescence, long particle strings are formed. A large structure of few centimeters in diameter, consisting of connected particle strings is observed. This negatively charged particle network floats in the plasma and is eventually deposited on the electrode surface.