Applications and challenges of low temperature plasma in pharmaceutical field

Low temperature plasma(LTP)technology has shown an outstanding application value in the pharmaceutical filed in recent ten years.This paper reviews the research advances in LTP,including its effects on enhancing or inhibiting drug activity,its combined use with drugs to treat cancers,its effects on the improvement of drug delivery system,its use in preparation of new inactivated virus vaccines,its use with mass spectrometry for rapid detection of drug quality,and the anti-tumor and sterilization effects of plasma-activated liquids.The paper also analyzes the challenges of LTP in the pharmaceutical filed,hoping to promote related research.

A STUDY ON THE STRUCTURE AND PROPERTIES OF POLYBUTYLALDEHYDE FORMED IN LOW TEMPERATURE PLASMA

The polybutylaldehyde obtained by plasma polymerization was investigated by means of IR, X-ray diffraction, GC-MS, elementary analysis, TEM, electron diffraction and contact angle measurements etc. The results showed that the polymer formed in plasma is amorphous crosslinked polymer, and its backbone is made of carbon atoms. The surface energy of the polymer film is independent of the polymerization conditions. No addition reaction has taken place in the carbonyl group of butylaldehyde in the plasma condition. The result of the wettability measurements showed that the polymer film is generally hydrophobic and the surface energy of the film is about 41 dyn/cm, in which the dispersion force contribution is the majority. The electron diffraction proved that some crystal substance, even the single crystals were present in the polymer. X-ray diffraction also proved the presence of crystal and showed about 15% crystaUinity fraction.

Oxidation Degradation of Aqueous Carbofuran Induced by Low Temperature Plasma

The oxidative degradation of aqueous carbofuran, a heavily used toxic carbamate insecticide by low temperature plasma, was investigated. The results show that the treatment efficiency increases with the increase in initial concentration. Raising the treatment temperature and changing the pH value can result in enhanced degradation of carbofuran in solution. The results also show that low temperature plasma treatment can effectively remove chemical oxygen demand （COD） of carbofuran in the solution.

Design of Thomson scattering diagnostic system on linear magnetized plasma device

In addition to the magnetic confinement fusion plasma,Thomson scattering has been applied to measure electron density and temperature of low-temperature plasmas.Based on a linear magnetized plasma device,a set of Thomson scattering diagnostic system is designed to diagnose the plasma with n_(e)=10^(18)–10^(19)m^(-3)and T_(e)=2–5eV.Due to low plasma temperature and density,this diagnostic system needs high spectral resolution and collection efficiency to meet the requirements of electron velocity distribution function measurements.Through the bench test,it is confirmed that the spectral resolution reaches 0.01 nm,and theoretical collection efficiency is high enough to obtain a Thomson scattering spectrum by 1000 accumulations.

Higher resolution helium measuring system for deuterium plasma on EAST tokamak via normal Penning gauge

Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA system was developed successfully in 2015,it was the first time that EAST could detect helium partial pressure in deuterium plasma（wall conditioning and plasma operation scenario）.With dedicated calibration and proper adjustment of the parameters,the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices.Moreover,the He and D2 partial pressures are measured simultaneously.At present,the measurable range of deuterium partial pressure is 1×10^-7 mbar to 1×10^-5mbar,meanwhile the range of helium is 1×10^-8 mbar to 1×10^-5 mbar.The measurable range can be modified by means of the adjustment of POGA system＇s parameters.It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms（the 200 ms because of conductance of transfer pipe at present）.The POGA system was routinely employed to wall conditioning and helium enrichment investigation in2015.Last but not the least,the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2 P,which has been suspended for a few years and was used for almost all the POGA systems in the world.

低温等离子治疗儿童鼻咽部第二鳃裂囊肿分析

目的探讨儿童鼻咽部第二鳃裂囊肿的临床特征和治疗方式,提高诊治能力。方法回顾性分析河北省儿童医院收治的4例儿童鼻咽部第二鳃裂囊肿的临床资料,包括年龄、性别、症状、影像学资料和治疗过程。总结分析病变部位特点,B超、CT或MRI特征,术后病理结果及治疗方式。结果4例鼻咽部第二鳃裂囊肿患儿均表现为鼻咽侧壁咽鼓管咽口与腭咽弓后上方连线上的囊性肿物,囊壁较厚,影像学检查结果均为囊性病变。4例患儿选择内镜下低温等离子病变切除术,其中2例为内侧囊壁大部分切除术,将囊腔充分敞开,2例为囊肿全部切除术。术后病理提示衬覆纤毛柱状上皮或复层上皮,周围淋巴组织增生。术后随访1.5~3年无复发。结论儿童鼻咽部第二鳃裂囊肿临床罕见,诊断主要依靠病变部位及术后病理结果,内镜下低温等离子切除病变组织是微创、安全、有效的治疗方式。

The Mutation Breeding and Mutagenic Effect of Air Plasma on Penicillium Chrysogenum

Low temperature air plasma was used as the mutation tool for penicillin-producing strain Penicillium chrysogenum. The discharge conditions were RF power of 360 W, temperature of 40℃ in a sealed chamber, and pressure of 10 Pa to 30 Pa. The result showed that the kinetics of the survival rate followed a typical saddle-shaped curve. Based on a statistic analysis, at the treating duration of 10 min, the positive mutation rate was as high as 37.5% while the negative mutation rate was low. The colonial morphology changed obviously when the plasma treating duration reached or exceeded 45 min. After both primary and secondary screening, a mutant designated as aPc051310 with high productivity of penicillin was obtained, and a strong mutagenic effect on P. chrysogenurn was observed in the process. It was proved that after five generations, the mutant aPc051310 still exhibits a high productivity. All the results prove that the plasma mutation method could be developed as a convenient and effective tool to breed high-yield strains in the fermentation industry, while expanding the plasm application at the same time.

Plasma Induced Degradation of Benzidine in Aqueous Solution

The degradation of benzidine in aqueous solution by the low temperature plasma was examined. The results showed that the concentration of medium and the value of pH have an appreciable effect on the degradation of benzidine. What is more important is that iron ions acting as a catalyst play an important role in this reaction. For exploring the degradation mechanism of benzidine, some of the intermediate products were recorded by HPLC(high performance liquid chromatography).

The Solubility of Natural Cellulose After DBD Plasma Treatment

Natural cellulose was treated by an atmospheidc DBD plasma. The solubility of cellulose in a diluted alkaline solution after the plasma treatment was investigated. The properties were characterized by X-ray photoelectron spectroscopy （XPS）, Fourier-transform infrared spectroscopy （FTIR） and scanning electron microscopy （SEM）. The results indicated that the surface of cellulose treated by the argon DBD plasma was significantly etched, and the relevant force of hydrogen bonding was decreased. This might be the essential reason for the solubility improvement of natural cellulose in the diluted alkaline solution. Through a comparison of two discharge modes, the atmospheric DBD plasma gun and the parallel plate capacitively coupled DBD plasma, it was found that the atmospheric DBD plasma gun was more effective in fragmentizing the cellulose due to its production of a high energy plasma based on its special structure.

Effect of Systematic Resonance on DBD Device

Abnormal phenomena that discharge performance declines with the increase in the frequency of power supply have been observed in many DBD devices. DBD systematic resonance formed by transformer leakage induction and equivalent capacitance of the dielectric layer is a key factor causing such abnormal phenomena. Therefore, the parameters of a DBD device should be optimized to avoid resonance damage and improve DBD discharge characteristics.

Investigation of stimulated growth effect using pulsed cold atmospheric plasma treatment on Ganoderma lucidum

Cold atmospheric plasma(CAP)driven by pulsed high-voltage power has specific advantages in various fields,such as the growth promotion of edible fungi in plasma agriculture.Compared with other strains,Ganoderma lucidum has the significant advantage of high medicinal value,but the shortcomings of low yield,long growth cycle,and an uneven market quality.In this study,Ganoderma lucidum was treated with a CAP powered by a homemade pulsed highvoltage power supply.Three groups of Ganoderma lucidum were treated under different conditions.The stalk lengths and pileus areas of Ganoderma lucidum were recorded to evaluate growth status.Results showed that treatment frequency affected growth status considerably.Ganoderma lucidum was treated with 40 s plasma once a week and showed an improved growth status with a 33.63%increase in average stalk length and a 28%increase in the number of individuals whose pileus areas was greater than the average.Meanwhile,the growth speed was accelerated.However,treatment at an excessive frequency would damage and slow down the growth of Ganoderma lucidum.

Investigation of biomass surface modification using non-thermal plasma treatment

The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon （O/C） ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-l-picrylhydrazyl （DPPH）. By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared （FTIR） spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment, The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of F-FIR wavenumbers of 1109-1363 cm-1. With increasing NTP treatment times, the absorbance （of the peaks in the PTIR spectra） for syringyl related C-H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.

Observation of the Emission Spectra of an Atmospheric Pressure Radio-frequency Plasma Jet

An atmospheric pressure plasma jet （APPJ） using radio-frequency （13.56 MHz） power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species （atomic helium, atomic oxygen and metastable oxygen） generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2（b1∑g^＋） are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity （777.4 nm） between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.

Characterization of Cable Gun Plasma with a Charge Collector Array

The density, drift velocity and reproducibility of the plasma produced by a cable plasma gun array have been measured with a charge collector array. The plasma is used to prefill a coaxial plasma-opening switch with a conducting time approaching 0.4 μs. The reproducibility of the plasma source in subsequent shots is better than 5%. Near the gun nozzle and the opposite electrode, the plasma density amounts to 1015cm-3, which is 2 times to 3 times that in the gap between the two coaxial electrodes. A plasma drift velocity of about 2.4 cm/μs is observed from the time of flight of the charged particles. Both plasma density and drift velocity increase almost linearly with the rise in charge voltage.

Axial uniformity diagnosis of coaxial surface wave linear plasma by optical emission spectroscopy

The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave generator.By optical emission spectroscopy,parameters of the argon linear plasma with a length over 600 mm are diagnosed under gas pressure of 30 and 50 Pa and different microwave powers.The spectral lines of argon and Hβ(486.1 nm)atoms in excited state are observed for estimating electron excitation temperature and electron density.Spectrum bands in305–310 nm of diatomic OH(Σ-Π+A X22 i)radicals are used to determine the molecule rotational temperature.Finally,the axial uniformity of electron density and electron excitation temperature are analyzed emphatically under various conditions.The results prove the distinct optimization of compensation from dual powers input,which can narrow the uniform coefficient of electron density and electron excitation temperature by around 40%and 22%respectively.With the microwave power increasing,the axial uniformity of both electron density and electron excitation temperature performs better.Nevertheless,the fluctuation of electron density along the axial direction appeared with higher gas pressure.The axial uniformity of coaxial surface wave linear plasma could be controlled by pressure and power for a better utilization in material processing.

Preparation and Characterization of PANI/PET Composite Conductive Fabric

Polyaniline /Polyester( PANI /PET) composite conductive fabric is prepared through in-situ polymerization process using aniline as monomer and PET fabric as matrix,which is treated with alkali deweighting and low temperature plasma. The property of PANI /PET composite conductive fabric is studied and characterized,including scanning electron microscope( SEM), infrared spectroscopy, conductivity, wash fastness and mechanical properties. The results show that the optimal polymerization conditions: the molar ratio of ammonium persulfate and aniline is1∶ 1,the concentration of sulfuric acid is 1 mol /L and reaction time is 90 min. Under optimum conditions,the surface resistivity of PANI /PET composite conductive fabric is about 170 Ω. After washed 5 times, the surface resistivity of PANI /PET composite conductive fabric is stable at 1 450 Ω. The breaking strength and breaking elongation of PANI /PET composite conductive fabric decrease compared with PET fabric.

The Experimental Investigations of Dielectric Barrier Discharge and Pulse Corona Discharge in Air Cleaning

The dielectric barrier discharge (DBD) and pulse corona discharge(PCD) plasma generator was used to remove NH3, H2S, C7H8 etc. from atmosphere. The principle and characteristic of the two ways was discussed in the article. The test shows the result of PCD is better than that of DBD.

Application of Electrostatic Probe in Wool Fabric LTP Finishing

By using a double electron probe the electron density and electron temperature were measured during the low temperature plasma （LTP） treatment of wool fabrics. The dependences of the electron density upon the power, pressure and the plasma-treating time was studied. The effects on the wool fabrics＇ shrinkage were studied. The results showed that the angle of the double electrostatic probe and the area of the treated fabrics had a strong impact on the density measurement. The felt-proof property of wool fabrics treated with an argon plasma was better than that with a nitrogen plasma. The gas, power and pressure of the LTP treatment all affected the electron density. The electron density increased with the increase in power and pressure. The electron density did not change significantly with treating time, in a certain range of both power and pressure of the LTP treatment.

Ions Bombardment in Thin Films and Surface Processing

Ions bombardment is very important in thin films and surface processing. The ion energy and ion flux are two important parameters in ion bombardment. The ion current density mainly dependent on the plasma density gives the number of energetic ions bombarding the substrate. The self-bias voltage in plasma sheath accelerates plasma ions towards the substrate. RF discharge can increase plasma density and RF bias can also provide the insulator substrate with a plasma sheath. In order to choose and control ion energy, ion density, the angle of incidence, and ion species, ion beam sources are used. New types of electrodeless ion sources (RF, MW, ECR-MW) have been introduced in detail. In the last, the effects of ion bombardment on thin films and surface processing are presented.

Designof a MT-DBD reactor for H2S control

This study aimed to discuss the removal of hydrogen sulfide （H2S） with non-thermal plasma produced by a multilayer tubular dielectric barrier discharge reactor,which is useful in the field of plasma environmental applications.We explored the influence of various factors upon H2S removal efficiency （ηH2S） and energy yield （Ey）,such as specific energy density （SED）,initial concentration,gas flow velocity and the reactor configuration.The study showed that we can achieve ηH2S of 91% and the best Ey of 3100 mg kWh-1 when we set the SED,gas flow velocity,initial H2S concentration and layers of quartz tubes at 33.2 J 1-1,8.0 m s-1,30 mg m-3 and five layers,correspondingly.The average rate constant for the decomposition of hydrogen sulfide was 0.206 g m-3 s-1.In addition,we also presented the optimized working conditions,byproduct analysis and decomposition mechanism.