Study On Wettability And Antifriction Of Textured Surface Of Cannula Electrode With Deep Brain Stimulation

Parkinson’s disease(PD)causes severe pain and suffering to patients.Deep brain stimulation is an effective method for the treatment of Parkinson’s disease,but the cannula electrode used in the operation can cause mechanical damage to blood vessels or brain tissue,and cause a variety of pathological reactions.One of the causes of tissue injury is the friction between the trocar electrode and the brain tissue,so it is of great research value to reduce the friction between the electrode and the brain tissue.In this paper,the influence of the surface morphology and wettability of the textured stainless steel tube electrode on the friction force was studied based on the idea of micro-textured friction reduction,so as to reduce the friction force during electrode implantation and improve the surgical effect.Based on the mechanism of surface micro-texture friction reduction and laser processing technology,a nanosecond UV laser was used to fabricate the grooved surface textures with different morphologies on the massive 316L stainless steel samples.The effects of laser processing parameters on groove size and surface profile parameters were studied by single factor experiments.A prediction model between laser machining parameters and the ablation amount of stainless steel surface was established based on BP neural network.The results show that the minimum average error of the prediction model is up to 3.27%,which can accurately predict the depth and width of the trench.Based on the wettability theory,the contact Angle of grooved texture surface was measured in distilled water and artificial cerebrospinal fluid(ACSF),and the relationship between laser processing parameters,groove spacing and surface wettability was studied.Four kinds of pit textures were machined on the surface of stainless steel,and the effects of pit size and pit spacing on the surface wettability were studied.The contact Angle of the textured surface in different storage media with time was observed and the superhydrophobic surface was prepared by low temperature annealing method.The results show that the contact Angle of the textured stainless steel surface is as low as 0° and as high as 159.2°.The grooves of different wettability and the pits of different shapes were fabricated on stainless steel needle by using the optimized laser machining parameters.A platform for measuring puncture force was established and samples of porcine brain were prepared.Puncture experiments were carried out with different textured steel needles under different lubrication conditions,and the puncture force curves were analyzed.The results showed that under the condition of artificial cerebrospinal fluid lubrication,the superhydrophilic grooved surface and elliptical pit surface showed the best antifriction performance.The texture size,texture spacing and puncture speed were optimized based on response surface methodology,and the friction force could be reduced by up to 46.4%after parameter optimization.