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Development Antifogging Agent of Nasal Endoscope and to Explore Its Mechanism

Author: WanLiangCai
Tutor: XieMinQiang
School: Southern Medical University,
Course: Otorhinolaryngology
Keywords: nasal endoscope antifog super hydrophilic nanoparticle superhydrophobic
CLC: R318.08
Type: PhD thesis
Year: 2013
Downloads: 114
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Abstract

Background:Transparent material has wide application fields in our daily life, in industrial,agricultural and medical aspects, the application of such materials as mirror, all kinds of medical endoscope, automobile windshield and agricultural plastic film makes our life more convenient. But the above material surface are easy to condense of water vapor, the fog affects the light transmittance or visibility which influence its application in high humidity or in lower temperature ares. In order to keep the good light transmittance or visibility, we must clean our medical endoscope lens again and again during the surgery which will prolong the operation time. Endoscopic antifogging problem has already attracted more and more attentions of scholars. Nasal endoscopic surgery has been widely developed in hospitals at all levels, nasal endoscopic technique is now becoming more mature, but the nasal endoscopic surgery complications, especially serious complications still occur from time to time, the reasons include bleeding, endoscope lens blurred or fog. Nowdays, medical betadine, alcohol, hot water or soap liquid are used to avoid the fogging clinically, but there are many disadvantages for these materials such as short antifog time, easy to burn nasal mucosa,high irritation, the issue of clinical endoscopic antifog is not resovled up to now. Although there are lots of reports about antifog in industry and agriculture, this kind of antifogging materials only require the high quality of antifog while ingore its toxicity and irritation, so the industrial and agricultural antifog material may not be suitable for clinical application. So far, clinical endoscopic antifog material is rarely reported in literature. Developping a kind of non-toxic, biological compatibility and high quality endoscopic antifog material is closely related with the clinical research.Usually antifog methods includes the following ways:first of all:make the material surface hydrophilic and reduce its surface energy, the hydrophilic material contains a large number of hydrophilic group which can attract water molecules,so the droplet in material surface can rapidly spread expands to form a layer of water film which reduce light of diffuse and achieve the purpose of antifog. hydrophilic materials includes:small molecule surfactant, organic polymer hydrophilic antifog coating, organic/inorganic hybrid hydrophilic antifog coating, oxide, photocatalysis hydrophilic surface, carbon nanotube materials. Secondly:contrast to the hydrophilic material, make the material surface hydrophobic, because hydrophobic material cannot be infiltrated by water droplets in its surface and water droplets can roll easily, so the hydrophobic material can avoid fogging theoretically, but the research reports about hydrophobic material antifog are rare, because superhydrophobic material has great potential in the basic fields and practical application, scholars become deeply interested in superhydrophobic material, methods of superhydrophobic material includ:sol-gel method, phase separation, chemical vapor deposition (CVD), etching method, electrostatic spinning technology, carbon nano tube, reciprocal transformation materials between superhydrophilic and superhydrophobic materials, the most commonly used methods is sol-gel method. Thirdly:increase temperature of the material surface and water vapor can’t condensate in endoscope surface and can achieve the purpose of antifog.When the superhydrophilic and superhydrophobic material are applied in nasal endoscopic antifog,they will face the following problems:droplets in the super hydrophilic material surface can form a layer of water film easily and unfold rapidly which can reduce light of diffuse and achieve the purpose of antifog, but the adhension between the liquid hydrophilic material of antifog dosage form and solid surface usually is mainly by physical adsorption,that is, by van der Waals force, the adhesive force is weak and unstable, the liquid hydrophilic antifog material can lose easily from the solid surface which can decrease the antifogging performance of the liquid hydrophilic material. To the superhydrophobic material, a rough structure should be built of its surface to achieve the hydrophobic state, and there is a positive correlation between hydrophobic ability and the material surface roughness,that is, the rougher of the material surface is, the better of hydrophobic performance is. Only when the material surface contact angle is about180degrees can the water droplets on the material roll freely, however, it is a ideal state.it also brings a new problem, that is, the better the hydrophobic surface is, the rougher of its surface is, which can influence the transmissivity of hydrophobic material and its applications.Objective:The study will develop a kind of antifogging agent for endoscopic sinus surgery with surfactant, solvent, dispersant, etc by orthogonal test, the antifoggant should be colorless, non-irritating, long antifog time, good transmissivity, economic,security and much easier to manufacture; to explore the changes of surface energy polarity ratio, adhesion between antifoggant and nasal endoscope lens, anti-fog time by modified antifoggant with different nanoparticles; in addition, to makes a preliminary discussion whether the superhydrophobic material has the function of antifog or not. Methods and materialsAccording to certain proportion,the hydrophilic antifogging agent was made by surfactant, solvent, dispersant, etc, each material weight percentage has three level, using design of orthogonal test. L27(35) of experiments were arranged by SPSS13.0. nasal endoscopy anti-fogging agent were made by adding the ethanol (A), propylene glycol (B), polyoxyethylene lauryl ether (C), sodium dodecyl sulfate (D), polyethylene glycol400(E) and deionized water to weighing bottles and mixed According to the order of A、B、C、D、E, then the weighing bottles were placed50℃water bath for15minutes.Each substance has three levels percentage of the total mass (A:1=3%,2=10%,3=20%; B:1=3%,2=10%,3=20%; C:1=3%,2=10%,3-20%; D:1=0.6%,2=2%,3-4%; E:1-0.6%,2=2%,3=4%), orthogonal test was designed by SPSS13.0.27kinds of nasal endoscopy antifogging agents were obtained by the different ratio,which are colorless, transparent, non-irritating, the pH value is about7～8. In accordance with the way of endoscopic surgery, StorzO0nasal endoscopy and its imaging system were used to test the antifogging time of the27agents,each agent was tested3times, and the average is antifogging time, while the medical betadine,95%ethanol were also tested as control.Developping a nanoparticles modified hydrophilic antifogging agent of nasal endoscope:adding0.05g nanoparticles of SiO2into5ml hydrophilic antifogging agent of nasal endoscope and adding0.05g nanoparticles of nano sio2-KH570into5ml hydrophilic antifogging agent of nasal endoscope. Then two kinds of nanoparticles modified hydrophilic antifogging agent were made by ultrasonic dispersion for30minutes.Developping a nanoparticles modified polyvinyl pyrrolidone antifogging agent of nasal endoscope:adding0.05g of nano zno into5ml polyvinylpyrrolidone solution, adding0.025g of nano titanium dioxide into5ml polyvinyl pyrrolidone solution, adding0.05g of hollow microspheres nano silica into5ml polyvinylpyrrolidone solution, Then three kinds of nanoparticles modified polyvinyl pyrrolidone antifogging agent were made by ultrasonic dispersion for30minutes.Different antifogging agent were characterized and the content includes:light transmittance, contact angle, antifog time (nasal endoscopic antifog test), adhesion work and transmission electron microscopy (SEM) and atomic force microscope.Study antifog performance of transparent super hydrophobic film:First super hydrophobic thin film was made by sol-gel method:acid sol preparation:8.36mL ethyl silicate (TEOS) is added into the80mL anhydrous ethanol and fully dissolved.4.8mL36%hydrochloric acid was dropped gradually into the above solution on magnetic stirrer, stirring for9hours. Acrylic acid solution preparation:3.0g acrylic acid was dissolved in50ml anhydrous ethanol, fully stir until completely dissolved. Alkaline gel preparation:3.1mL ethyl orthosilicate (TEOS) and13.8mL deionized water were added into the80mL anhydrous ethanol, and then4.7mL ammonia solution was added into the above solution gradually on the working magnetic stirring, the solution was sealed and reaction for1hour. Different proportion of acrylic acid solution and alkaline gel were added into the anhydrous ethanol and was dispersed by ultrasonic oscillation for1h,20kinds of dispersive sol were made, clean glass was dipped into above sol for10s, then the clean glass was pulled out by coating machine with speed of3mm/s, and planced it for about15minutes at room temperature, because of the surface adsorption and chemical bonding force, the sol will form a layer of uniform film on the surface of the substrate,3layers and5layers coating were made. The substrates were put into the muffle furnace and increased the temperature to400℃in2hours, heat preservation for0.5h and natural cooling, transparent silica film samples were made.the glass coated with silica film coating were dipped into the silane coupling agent hydrophobic liquid and immersed for3hours, then the sample were put into the100℃oven drying for sixty minutes and transparent hydrophobic silica film were done.The antifogging performance of the samples No.8and No.13which were hydrophobic were tested, methods:simulation certain temperature difference, the antifogging performance of the samples of coating substrate, the blank substrate and silane coupling agent coating substrate were test. The substrate were put on thermo static water bath and the silica layer face to the surface of the water the distance between the substrate and water surface is3cm, room temperature is13℃, the temperature of water in the Water Bath is set to60℃. After5min,10min, and min,30min, the antifogging performance were observed.Statistics (chapter1) factors A:anhydrous ethanol; Factor B:propylene glycol; Factor C:lauryl alcohol polyethylene glycol ether factor D:sodium dodecyl sulfate; Factors E:polyethylene glycol (peg)400,the weight percentage of each material has three levels (a:1=3%,2=10%,3=20%; b:1=3%,2=10%,3=20%; c:1-3%,2=10%,3=20%; d:1=0.6%,2=2%,3=4%; E:1=0.6%,2=2%,3=4%) if you want todo all the test completely,there need to do3by3by3by3by3=243times test (Orthogonal), the Orthogonal test was designed by SPSS13. the results of antifogging performance were analyzed by variance.Results:By the orthogonal experiment, we made27kinds of different concentration of antifogging agent, the antifog time and antifogging performance of all the27samples were characterized, the best ratio (A3B2C3D3E3) of weight percentage of each material was got according to the average analysis of the different components, the transmissivity of all the antifogging agent are close to100%; Contact angle is about 7.6degrees; Scanning electron microscopy (SEM) shows that the antifogging agent form a flat layer on the surface of nasal endoscopic lens (sapphire); another sample was made according to the best ratio and was tested, the average antifog time is15minutes. As control, the transmissivity of medical betadine its about80%; Contact angle is about10degrees; Scanning electron microscopy shows that the medical betadine coating is scattered island and irregular, failure to form a flat layer on the surface of nasal endoscopic lens (sapphire), the average antifog time is04’05".the antifogging agent made by ourself was better than95%ethanol (38") and medical betadine.Antifogging performance of antifogging agent and modified antifogging agent: the average antifog time of antifogging agent modified by SiO2is18minutes; the average antifog time of antifogging agent modified by nano SiO2-KH570is21minutes. Light transmittance:in the visible light range, the light transmittance of antifogging agent is about100%; the light transmittance of antifogging agent modified by SiO2is about90%; the light transmittance of antifogging agent modified by nano SiO2-KH570is about97%. Contact Angle:the contact angle of water droplets on the antifogging agent coating is about7.8degrees; the contact angle of water droplets on the antifogging agent modified by SiO2coating is about7.0degrees; the contact angle of water droplets on the antifogging agent modified by nano SiO2-KH570coating is about6.7degrees. Adhesion work:The contact angle between water and the surface of sapphire is about (56.159.958.0) degrees, the average is58.0degrees; The contact angle between ethylene glycol and the surface of sapphire is about (46.351.648.2), the average is48.7degrees; the surface energy of sapphire is52.36±mN/m, the dispersive component is2.92mN/m; the polar component is49.44mN/m; the adhesion work between the antifogging angent of nasal endoscope and the sapphire len is40.71mN/m, the adhesion work between the antifogging agent modified by SiO2and the sapphire lens is49.73mN/m, the adhesion work between the antifogging agent modified by nano SiO2-KH570and the sapphire lens is55.38mN/m. Transmission electron microscopy (SEM):diameter of SiO2is about100～200nm, spherical, the dispersion of nano SiO2in the antifoggant is poor; the dispersion of nano SiO2-KH570in the antifoggant is obviously improved, it presents single nanoparticles distribution. Atomic force microscope:the newly developed antifogging agent form a uniform and smooth layer on the surface of nasal endoscope(sapphire),the thickness is about192.30nm; antifogging agent modified by SiO2form a slightly rough layer on the surface of nasal endoscope(sapphire),the thickness is about200.09nm; antifogging agent modified by nano SiO2-KH570form a rough layer on the surface of nasal endoscope(sapphire).Antifogging performance of PVP and modified PVP:the average antifog time of PVP is10minutes; the average antifog time of PVP modified by nano zno is15minutes; the average antifog time of PVP modified by nano titanium oxide is16minutes; the average antifog time of PVP modified by hollow nano silica is17minutes. Light transmittance:in the visible light range, the light transmittance of PVP is about100%; the light transmittance of PVP modified by nano zno is about90%; the light transmittance of PVP modified by nano titanium oxide is about85%; the light transmittance of PVP modified by hollow nano silica is about92%.The light transmittance of betadine is about80%; The light transmittance of nano titanium dioxide modified betadine is about70%. Contact Angle:the contact angle of water droplets on the PVP is about9.6degrees; the contact angle of water droplets on the PVP modified by nano zno coating is about5.9degrees; the contact angle of water droplets on the PVP modified by nano titanium oxide coating is about4.8degrees; the contact angle of water droplets on the PVP modified by hollow nano silica coating is about6.1degrees. Adhesion work:the adhesion work between pvp and the sapphire lens is96.10mN/m, the adhesion work between the PVP modified by nano zno and the sapphire lens is101.02mN/m, the adhesion work between the PVP modified by nano titanium oxide and the sapphire lens is100.81mN/m, the adhesion work between the PVP modified by hollow nano silica and the sapphire lens is102.92mN/m. Transmission electron microscopy:the dispersion of nanometer zinc oxide in PVP solution is good; the diameter of nano titanium oxide particle which was made by ourself is about120～160nm and well dispersive in PVP solution; the diameter of hollow nano silica particles which was made by ourself is about200nm and also well dispersive in PVP solution. Atomic force microscope:the newly developed antifogging agent of pvp form a uniform and smooth layer on the surface of nasal endoscope(sapphire),the thickness is about78.30nm; PVP modified by nano zno form a slightly rough layer on the surface of nasal endoscope,the thickness is about277.97nm; PVP modified by nano titanium oxide form a rough layer on the surface of nasal endoscope, the thickness is about227.34nm; PVP modified by hollow nano silica form a rough layer on the surface of nasal endoscope,the thickness is about34.64nm.Because of phase separation and self-assembly silane coupling agent,20kinds of coating were made with acrylic induction and ethyl silicate (TEOS) on glass substrate by sol-gel method, the samples of No.8～13were hydrophobic, the best one which has superhydrophobic properties is No.13. Scanning electron microscopy (SEM) shows the microstructure of the film surface is crater form, the contact angle of the surface of the coating is about153°which made the sample has superhydrophobic properties, antifog test shows that it has certain antifog performance, in the visible light range, the light transmittance of the super hydrophobic coating is about80%.Conclusion: The hydrophilic antifogging agent of nasal endoscope by orthogonal design has some excellent properties such as transparent, non-toxic, tasteless. Its antifog time is much longer than that of the clinical commonly used betadine and alcohol; The nano silica particles modified hydrophilic antifogging agent of nasal endoscope prolong the antifog time evidently and improve the antifogging performance; Nanoparticles modified poly vinyl pyrrolidone antifogging agent of nasal endoscope is transparent, non-toxic, tasteless, its antifog time is also much longer than that of the betadine and alcohol. Superhydrophobic material has certain antifog performance, but its surface is rough and the light transmittance is not so good, it is difficult to make a coating with the surface contact angle of180degrees, it need to be further study of transparent super hydrophobic coating to be applied to clinical antifog of nasal endoscope.

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