An Encrustation Model for Urinary Catheter Assessments
requiring long term urinary catheterization suffer from encrustation and catheter
blockage, issues associated with urinary tract infections, urine reflux, and kidney
failure. The encrustation model developed here establishes a high-throughput assay to
evaluate comparative encrustation formation as a function of different substrates and
surfaces. This design uses a peristalt... read moreic pump to continuously cycle artificial urine
through a bioreactor that houses twelve hanging catheter samples. Moreover, a separate
pump line introduces urease to mimic Proteus mirabilis production of urease. The system
produces measurable encrustation within 1.5 hours and showed further encrustation growth
as a function of solution refreshments and time. Confocal microscopy, scanning electron
microscopy, energy-dispersive x-ray spectroscopy, and attenuated total reflectance
Fourier transform spectroscopy analysis confirmed the formation of struvite and apatite.
All encrustations were dissolved in acid and quantified using the Calcium
o-Cresolphthalein Complexone protocol, a calcium colorimetric assay. Consistency of
encrustation formation between sample positions and along sample lengths was evaluated.
Subsequently, the effects of surface roughness, radiopacifiers, surface charge, and
substrate material on encrustation was evaluated using the encrustation assay. The
results showed that polyether and polyester polyurethanes had greater calcium
encrustation resistance compared to silicone (p < 0.001), a commonly used material
for long-term bladder catheterization, and the polycarbonate polyurethane control (p
< 0.001). No statistical difference was found between samples with barium sulfate and
without barium sulfate; samples coated with polyelectrolytes and uncoated samples; and a
4.6x rougher surface and control. The material comparison study provided valuable
information for developing next-generation catheters that resist catheter-associated
Thesis (M.S.)--Tufts University, 2017.
Submitted to the Dept. of Biomedical Engineering.
Advisors: Jonathan Zhang, and David Kaplan.
Committee: Qiaobing Xu.
Keywords: Biomedical engineering, and Engineering.read less