Figure 3.

Sensor Performance Following Tethering to Hydrated Hydrogel [30% AAm 15, AAm/MBAm]

(A) Fluorescence emission spectra of hydrated hydrogel exposed to different concentration of phenylalanine solution and excitation at λ = 470 nm (n = 8). Inset shows the schematic of phenylalanine-responsive fluorescent aptamer sensor.

(B) Fluorescence intensity concentration response for hydrated hydrogel with excitation λ = 470 nm and emission λ = 520 nm (n = 8). The curve was fit using a Padé approximant.

(C) Response time for hydrated hydrogel after addition of 500 μM phenylalanine solution (n = 8).

(D) Fluorescence intensity for hydrated hydrogel disks with excitation λ = 470 nm and emission λ = 520 nm after soaking in PBS for 5 days with PBS changed daily. Hydrogel disks were fabricated using aptamer with or without the 5′-acrydite modification. The dotted line indicates the average fluorescence for a hydrated hydrogel disk with no aptamer (n = 3). Data analyzed using two-tailed t test. “**” indicates significant at p < 0.01.

(E) Fluorescence intensity for hydrated hydrogel with excitation λ = 470 nm and emission λ = 520 nm after cycling through different concentrations of phenylalanine (n = 3).

(F) Hysteresis loop showing the fluorescence intensity for hydrated hydrogel with excitation λ = 470 nm and emission λ = 520 nm after increasing and decreasing phenylalanine concentration (n = 3).

Data are represented as mean ± standard deviation. See also Figures S3–S5.