Fig. 1.

The concept of aptamer-functionalized hydrogels and aptamer retention within gelatin methacryloyl (GelMA) hydrogels. (A) Schematic representation of photo-crosslinked GelMA with 5′acrydite-modified VEGF₁₆₅ specific aptamer sequence, in the presence of photoinitiator (Irgacure 2959) and UV light. (B) Schematics explaining the concept of 5′acrydite-modified aptamers being covalently linked into GelMA network, whereas, due to the absence of 5′acrydite group (red circle), the control-aptamers are freely diffusible within the polymer network. Due to molecular recognition, upon addition of 5′-fluorescently labelled complementary sequence (Fluoro-CS) in the 5′acrydite-aptamer-functionalized hydrogels (Acrydite Aptamers) and control-aptamer-functionalized hydrogels (Control Aptamers), the Fluoro–CS–aptamer hybridization occurs. (C) The fluorescence microscopic images of the GelMA, “Control Aptamer” and “Acrydite Aptamer” -functionalized hydrogels after 24hrs incubation with Fluoro-CS at 37 °C. #D10 indicates the brightfield images of hydrogels on day10. The fluorescence intensity corresponding to the presence of Fluoro-CS indicates the presence of aptamers within the hydrogels at various time-points. The red dotted line in GelMA hydrogels from day2 onwards shows the hydrogel border. The mean fluorescence of all samples over different time-points have been shown in the graph. The experiment was performed with n = 3 experimental replicates and values are represented as mean ± SD.