Design:We identified the spectral properties that we would be measuring (wavelength and absorbance) and hypothesized its potential changes when the aptamers and peptides are added
Build:We built three different chips with different materials (glass, PDMS and plastic)
Test:The functionalized chips were then placed into a UV-Vis spectrophotometer and the absorbance was measured as a function of wavelength. This graph was plotted across the different materials and analyzed.
Learn:We realized that glass is the ideal material for this application as its transparency and absorbance when aptamers and peptides are present is easier to characterize with the spectrophotometer that we had available to us.
Throughout the experiment, we embodied the engineering design process. Starting from clearly defining the problem, planning potential approaches, designing the solution, implementing it, and finally improving upon it. One of the ways in which we demonstrated this was through finalizing our choice of substrate to functionalize the gold nanoparticles (AuNPs). We have to take into consideration the cost, accessibility, functionality, and overall performance. Based on these considerations and consultation with other experts, we shortlisted three candidate substrates - glass, polydimethylsiloxane (PDM), and plastic. We functionalized all three of the substrates with AuNP and carried out the absorbance measurements. While plastic is desirable because of its relative inexpensiveness, the absorbance values were the lowest. PDMS gave comparable results to glass, however, the exact protocol needs to be further optimized as the functionalization with AuNP did not give consistent results. A graph showing the comparison between PDMS and plastic film is shown in the figure below. Glass has excellent transparency and has been extensively used in literature. In this way by considering all alternatives, we were able to come up witht the best possible solution with the resources available. In addition to this, we used the engineering design cycle in optimizing other crucial factors such as the incubation times for plasma treatment, APTES, AuNP, aptamers, and peptides.
The above process clearly indicates the engineering cycle that we implemented for choosing the base material for our platform.
Figure: Absorbance spectra for PDMS and plastic film functionalized with AuNP.
