Alginate affairs
Week three has been loosely focused on forming alginate gel blocks with a gold nanoparticle top layer. This will hopefully allow the antibodies easier access to the nanoparticles in any potential future conjugation process. We say loosely because it has also been a week where we have learnt to use and make 3D printed craft files and implementing them into our gel making process. So on Tuesday (14/07) we 3D printed our first ever mold. The mold contains 9 wells of increasing dimensions (3×3, 4×4, 5×5, 6×6, 7×7, 8×8, 9×9, 10×10, 11×11 & 12×12 mm respectively) but constant depth of 3mm. The mold took 1hr and 40mins to print. So we began using our molds on the Wednesday.
Wednesday morning began with us preparing a stock solution of HAuCl4 (4mM), 1% sodium alginate solution, 1% calcium chloride solution and a 1% solution of sodium citrate. The first stage was the synthesis of the alginate, this was achieved by filling each of the wells with 1% sodium alginate and immersing the wells in 1% sodium citrate – we set the gelling time as 10 minutes. After gelation was complete, the excess calcium chloride solution was removed and washed with distilled water. We then covered the newly formed alginate gels with HAuCl4 and allowed the gold solution to diffuse into the surface of the alginate for 15 minutes. After 15 minutes had passed, the excess gold was pipetted out and the remaining gold-soaked alginate was immersed in sodium citrate solution (the reducing agent).
Further into our project, we hope to implement these gold-alginate gels into our diagnostic tool prototype.