Schematic illustration of the preparation of PEG hydrogel microcolumns and photopolymerization process. (a) The prepared PEG precursor containing the indicator reagents was injected into the microchannels. (b) PEG hydrogel microcolumns array was formed by in situ UV photopolymerization using a fluorescence microscope. (c) The unpolymerized hydrogel precursor solution was removed by buffer. (d) Urine samples were injected into the channels to obtain the color changes. (e) A photographic image of the whole microfluidic device. A Y-shape channel was fabricated for multiple components simultaneous detection. (f) An enlarged microscopic image for the detection area.
Principles of UV-initiated polymerization of the PEG microcolumn array (a) and the modification of the glass surface by TPM and linked with a three-dimensional PEG hydrogel structure (b).
Cross-sectional view of the PDMS device showing PEG hydrogel microcolumns formed using flow lithography. The UV light regulated by the field diaphragams is projected from the bottom to form microcolumns in a film of oligomer that is enclosed in the PDMS device. The microcolumns formed are adherent to the glass slide, and separated from the top walls of the device by a thin oxygen inhibition zone consisting of un-cross-linked oligomer.
The diameters of circular hydrogel microstructures generated using different configurations of photolithography. The error bars are too small to label on the plots. 10×, 20×, and 40× represent the objectives we used. 6○ and 5○ represent the field diaphragms we used.
Color changes evaluation obtained by varying the concentrations of BSA (a) and glucose (b). The value for each concentration was calculated by the average from five times detection, separate.
Results for the quantification of proteins and glucose in real human urine samples. The dashed line indicates the clinical relevant concentration limit for diabetes diagnosis.
Comparison of the results by proposed method and hospital analysis.
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