Week Nine Progress

The progress underwent during week nine of the hydrogel restructuring module entailed rectifying the errors made during the first and second testing rounds conducted during week seven. The results of first and second testing trials revealed egregious errors upon obtaining the results of the spectrophotometry of week eight. The spectrophotometry results delineated a consistent decrease in fluorescent intensity over time. Nonetheless, an ideal graph would illustrate a sustained increase in fluorescent intensity, thereby paralleling an increase in the percentage of therapeutic that is released. The increase in fluorescent intensity which had resulted from the week seven testing may be attributed to the experimental errors which occurred during the construction of hydrogel samples, and are described in full detail in the Week Eight Progress Report.  During week nine, new hydrogel samples were generated in a comparable fashion to the construction of samples during the second phase of testing. In contrast, the third testing phase was altered such that pure water was not removed from the test tubes containing the four variant hydrogel densities during intervals of six hours. Instead, the supernatant contained in each test tube was removed during four, six-hour intervals, then subsequently transferred to a sets of Eppendorf tubes, marked and differentiated by the hours in which the samples were obtained. After obtaining supernatant samples during each interval of time, the supernatant contained within the test tubes was removed and subsequently replaced with the addition of 10-mL of pure water. The improvements made in testing methods had attributed to the amelioration of results, as evidenced by figure 1 delineating the fluorescent intensity over time.

Figure 1. Fluorescent intensity over time of variant hydrogel densities

Moreover, the construction of a standard curve enabled the solidification of the experimental results obtained during week nine. The construction of a standard curve entails the graphing of the known properties of multiple samples, thus allowing the same properties to be determined for unknown samples by interpolation on the graph. Thus, through the construction of a standard curve, as evidenced in figure 2, the fluorescence of the prototype therapeutic agent, FITC-BSA, was converted into the percentage of FITC-BSA released over time. The results were subsequently graphed, as evidenced by figure 3.

Figure 2. Standard curve generated for FITC-BSA

Figure 3. Illustration of the percentage of FITC-BSA release over time 

The experimental results of the third testing phase has provided for solidified data to be used during the prototyping phase of the module. As such, the procured data was utilized during the initial prototyping phase, in which, sheets of hydrogel samples were created to be ultimately generated into a two-layered hydrogel adhesive. The graph illustrating the percentage of FITC-BSA released over time, identified an ideal release rate for the layered hydrogel sample, thus a layered hydrogel adhesive design was solidified for the final stages of construction. Furthermore, during the initial prototyping phase, the methods in which to construct hydrogel sheets were devised. The process is illustrated under the Tutorial page.