| Other Abstract | The medical catheter can connect the inside and outside of the human body and
is widely used in clinical treatment. However, the invasive operation of the medical
catheter can easily cause tissue trauma, thus increasing the risk of infection in
patients. In order to reduce patients' adverse medical experience, it has become the
development trend of catheter preparation technology to treat and modify the
functional properties of medical catheter surface by adding coating. Therefore, it is of
great significance for the production and clinical application of medical catheter to
study the friction and adhesion properties of functional coating for medical catheter.
An important challenge is to characterize the mechanical properties of a functional
coating/conduit system with a soft coating/soft substrate architecture.
In this paper, the medical catheter as the research object, independently
developed the test instrument for soft coating/soft matrix catheter sample friction
performance test, simulated the service conditions of the catheter in the human body,
carried out a series of friction tests, characterized the surface coating of the catheter
lubrication and adhesion properties. Combined with finite element simulation method,
the mechanical properties of catheter coating in human body bend environment were
studied. The main work is as follows:
(1) Study on tribological properties of urethral lubrication coating. The thickness
of lubricating coating for medical catheter was measured. A device for measuring the
friction properties of the coating with confining pressure was developed, which can
simulate the application environment of the medical catheter. The experimental device
was used to conduct friction experiments on medical catheters with different
substrates and diameters. It was found that the sliding friction coefficient representing
the lubricating coating of medical catheter was not affected by the geometric size of
catheter, substrate material, confining pressure and sliding rate. The maximum static
friction force of the PVC catheter was analyzed. It was found that the faster the
sliding speed was, the greater the maximum static friction force of the PVC catheter
was. Therefore, the experimental device can reasonably characterize the sliding
friction coefficient of the lubricating coating on the medical catheter surface.
(2) Study on adhesion property of medical catheter coating. Optical microscope
was used to observe the morphology of the coating on the ureter surface, and the
changes of cracks on the coating surface were observed when the ureter was stretched.
The adhesion property of the medical catheter coating was characterized by the
tribological property test device of the tubular soft matrix coating. Several friction
experiments were carried out to monitor the shedding of coating by the change of
sliding friction force, and the changing rule of sliding friction coefficient of coating
with the number of experiments was obtained: the catheter with smaller changing rate
医用导管涂层围压式摩擦实验技术研究与性能表征
IV
of sliding friction coefficient had smaller shedding area of coating under optical
microscope, which proved that its surface coating had better adhesion performance.
The evaluation of the adhesion property of the coating can provide a basis for
selecting the lubrication coating with reliable adhesion property.
(3) Mechanical simulation of the movement of medical catheter in human
urethra tissue. The finite element model of catheter friction experiment was
established, and the simulation results were consistent with the experimental data,
indicating that the model can be used to simulate catheter friction performance. On
this basis, three conditions of single horizontal insertion, torsion after horizontal
insertion and torsion insertion were simulated in adult male urethral bending model,
and the thrust force of urethral insertion, force on urethral inner surface and force on
urethral outer surface coating were compared and analyzed under different conditions.
The results can provide reference for clinical application and production of medical
catheter.
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