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Week Five Progress

During week five, more research was done and the group was able to decide on the exact concentrations of calcium chloride to use in making each hydrogel layer as well as in the beads. The higher the concentration of calcium chloride, the more dense the hydrogel layer will be. Thus, for the thin, low-density layer, as well as for the low-density beads, a 5% calcium chloride solution will be used. For the thick, high-density layer, a 7% calcium chloride solution will be used. Refer to Figure 1, below, for a visual of the design.


Figure 1: Preliminary Diagram of the Hydrogel Wound Dressing 



Another task that was completed this week was additional planning for the testing phase. Once the hydrogel has been constructed, samples of it will be placed into cuvettes, and fluorescently-labeled bovine serum albumin (FITC-BSA) will be injected into the cuvettes, one at a time, in intervals of four hours. This will occur over a period of two days, and at the end of the two days, these samples will be brought to the lab and their absorbances will be measured. The absorbance value will be measured at a wavelength of 280 nm. This wavelength is shown below in Figure 2 as the second optimal wavelength at which to measure the absorbance. The absorbance cannot be measured at a wavelength of 495 nm, because FITC-BSA loses its fluorescence too quickly for our purposes when exposed to light at this wavelength.
Figure 2: Absorbance Spectrum of FITC-BSA [1]


Upon measuring the wavelength of each of the samples, the concentration of dye that has seeped through each sample will be calculated using the absorbance value and the standard curve, pictured below in Figure 3. This will give an indication of the amount of therapeutic that could seep through the hydrogel in that amount of time.
Figure 3: Standard Curve of Concentration vs. Absorbance for FITC-BSA [2]


References:
[1] N. Barbero, C. B., and G. Viscardi, UV-Vis spectrum of the BSA bioconjugated with FITC. 2016.
[2] R. J. Rivers, J. B. Beckman, and M. D. S. Frame, absorbance versus dye concentration curve of FITC-BSA. Journal of the American Society of Anesthesiologists, 2001.

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