Development,Physicochemical Properties And Animal Experiments Of Ni-Ti Alloy Superslip Guide Wire

Objective:Develop a guide wire with both super-slip performance and super-elasticity.Besides,test physicochemical properties and evaluate the damage to the vascular endothelial of rabbits.Methods: The super-thin hydrophilic coating on the surface of the guide wire was achieved by automatic continuous electrochemical processing technology,continuous rapid coating technology(for coating polymer layer),long-acting molecular crosslinking of medical hydrophilic polymer,and a new type of super-slippery Ni-Ti alloy wire was fabricated by ultra-high frequency and ultra-short-time automatic end-sealing equipment,Then the basic properties were studied by biocompatibility and physical properties in vitro.Animal experiment:12 rabbits were randomly divided into two groups A and B.In group A,the normal common carotid artery,renal artery,upper limb artery,and hepatic artery were tested with Nitinol alloy superslip guidewire,ollowing performances were observed and compared:(1)The correspondence between guide wires and catheters,that is,the friction generated when the wires are inserted,retracted and rotated in the catheters,and the resistance appears when the wires and catheters drop out.(2)The ability of the guide wires to drive the catheter,that is,the supporting role of the guide wire in parallel with the catheters,and the driving role to the catheters when passing through the vessels with larger curvature.(3)The ability of the guide wires to enter the blood vessels at different placket angles.(4)Thrombosis caused by guide wires in catheter and blood vessel.(5)The observations and comparations in the deformations between the tip of guide wires before and after the experiments.(6)The observations in the integrity of the surface of the guide wires under a microscope.In group B,normal common carotid arteries,bilateral renal arteries and bilateral upper limbs were tested with Ni-Ti alloy super-slip guide wire and Terumo radifocus guide wire respectively.On the 1st,7th and 14 th day after operation,two rabbits in the experimental group and the control group are executed respectively.Bilateral internal carotid artery,bilateral upper limb artery and bilateral renal artery are dehydrated and embedded and paraffin sections are prepared for histomorphological analysis.Histological structure of arteries(the de-endothelium and the formation of neonatal endothelium)is observed with hematoxylin-eosin staining,and markers related to cell proliferation(PCNA)is detected by immunohistochemical staining.Results: There was no obvious acute systemic toxicity,intradermal reaction,thermogenicity,in vitro cytotoxicity,delayed hypersensitivity reaction and hemolysis in Ni-Ti alloy Super-slip Guide Wire.The average friction of Ni-Ti alloy super-slip wire is 0.081 N.The average phase transition temperature of it is 8.5?.The average water absorption rate of it was 2.42%.The Tip of it rotates one circle,the average number of rotation cycles required at the proximal end is 1.42 cycle.the average number of cycles required for the deformation of it is 23.7 cycles.The average breaking force of it is 13.953 N.the average breaking force of it is 0.258oz*in.it have good developability under X-ray.In the 3D simulated coronary model,it can reach the mouth of coronary artery smoothly along with the elbowed catheter.The friction of it when they are inserted,retracted and rotated in the catheters is small,and the resistance of it dropping out of catheters is small.it could successfully reach bilateral common carotid artery,bilateral upper limb artery,bilateral renal artery,hepatic artery,and could lead the elbowed catheter into common carotid artery,renal artery and hepatic artery in rabbits.After the experiment,the guide wire pulled out and observed under the microscope was observed that no thrombus was attached to the surface of the guide wire.Besides,the tip of guide wire was not deformed compared with that before the experiment.Pathological specimens of the common carotid artery,upper limb artery and renal artery in rabbits(1st,7th and 14 th day after the experiment)showed No endothelial injury and endothelial hyperplasia were found in this h-e staining,and no PCNA expression was found in the immunohistochemical detection.Conclusion:Ni-Ti alloy super-slip guide wire is biocompatible.Compared with the same type of lead silk currently used in clinic,it has the advantages of less friction and better elasticity.There was no obvious endothelial injury to vessels larger than 1.3mm in diameter.