Throughout this week, we have been trying to adapt and optimise the formation of the AuNPs-alginate gels. We have been successful in forming gold layers onto of the alginate gels which can been seen in figure 1. However, the main problem we keep on encountering is that the gold nano particles are too embedded into the alginate matrix.
This is a problem because at some point we require the gold nanoparticles to attach to the antibodies. To resolve this issue we have been varying the concentration of the alginate, calcium chloride, chloroauric acid and reducing agents (both L-ascorbic acid and sodium citrate respectively).
If we decrease the concentration of the alginate by too much then the gels lose their shapes and are virtually liquid. However, increasing the concentration of alginate causes the AuNPs to aggregate and turn violet-blue. We hope to solve this premature aggregation issue by capping the gold nanoparticles with butanethiol as a sort of aggregation shield.