Fabrication of Rapid Diagnostic Kit Casing Using Modified Biodegradable Paper Materials as an Alternative to Plastic
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Date
2019-07
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Publisher
Kenyatta University
Abstract
The high population growth rate, emerging diseases and high cost of health care in
developing countries has led to the high demand of rapid diagnostic test (RDT) kits.
Rapid diagnostic test kits are medical devices used in early detection of diseases
among the population living in areas with limited medical facilities. The portability
and reliability of kits reduces medical cost incurred by inaccurate disease diagnosis.
To meet this demand plastics are enormously produced as basic raw material in
production of the kits. Plastics are often preferred because they are cheaper than their
corresponding biopolymer. The most devastating menace from plastic is its high solid
waste accumulation due to slow biodegradation. The study sought to modify selected
paper materials and tree barks to mimic plastic properties to replace plastic in rapid
diagnostic test kits. The selected papers were purchased from Nairobi County (Kenya)
shops while selected tree barks were collected from farms within Kiambu County
(Kenya). On modification with trichloro (lH, IH, 2H, 2H perfluorooctyl) silane at
different reaction times insitu, the paper and polished tree barks surfaces displayed
water contact angles between 90.14° to 144.60°, which indicated they were
hydrophobic. The tree barks were however discontinued for further analysis due the
limitation of cutting tools available. The modified paper did not attain
superhydrophobicity since the water droplets placed on its tilted surface remained
sticky rather than rolling as expected with superhydrophobic surfaces. The surface
energy of modified paper materials displayed low critical surface energy values
ranging from 27.9 to 40.0 dynes/em. The tensile strength of the unmodified and
modified selected paper did not show any significant difference at P<O. 05 and it was
within a range of 331.5 vs 323.9 (MPa) for classical method (CM) and 310.8 vs 299.8
(MPa) for dynamic mechanical analyzer (DMA). The moisture content of modified
selected paper samples was 4.41% which was significantly lower at p<0.05 than
5.42% of unmodified material. The organic matter content of the unmodified paper
was 68.77% and 67.41% for modified paper with no significant difference at p<0.05.
The calorific value of unmodified paper materials was 13.92Kj/g and 15.86Kj/g for
modified paper which differed significantly at p<O. 05. Scanning electron microscope
(SEM) analysis on modified samples showed growth of nano particles -70 nm on
surface. Focused ion beam (FIB) confirmed the solid nature of the nano particles. X ray diffraction (XRD) spectra for modified and unmodified selected paper were
similar, indicating that the bulk structure was not interfered by modification. Coupled
thermal gravimetric analyser, Fourier transform infrared and mass spectrometer
(TGA-FTIR-MS), displayed C02, H20 with traces of byproduct CO as the
combustion products of modified paper; however, no harmful HF was detected.
Energy dispersive X-ray Spectroscopy (EDX) and X-ray photoelectron spectroscopy
(XPS) confirmed the presence silicon and fluorine on the surface of modified paper.
The rapid diagnostic test kit casing was fabricated using modified blotting paper (P51)
with established optimum chemical and mechanical properties. The biodegradation of
fabricated casing was complete within 12 months; however, there was no observable
biodegradation on plastic controls within the same period. The findings of this study
will be disseminated to relevant authorities for sensitizing the public on the use of
cellulosic materials over plastic in rapid diagnostic test kits (RDTs).
Description
A Research Thesis Submitted in Fulfillment of the Requirements for the Award of the 'Doctor of Philosophy Degree of (Chemistry) in the School of Pure and
Applied Sciences of Kenyatta University. JULY, 2019
SUPERVISORS
Margaret Mwihaki Ng'ang'a
Naumih M. Noah
Martin Thuo Mwangi