The synthesis of the polymer bridge exclusively toward SiO 2 and gold followed the same procedure as above, but with target modification degree of 3:1 of hexylamine and ethylthiol respectively. Briefly, an aqueous suspension of TiO 2 P-25 (Sigma Aldrich, 21 nm primary size, 1 w/v%), Urea (Sigma Aldrich, 0.7w/v%), and HAuCl 4 • 3H 2 O (Sigma Aldrich, 0.5 w/v%) was heated to 90C and stirred at this temperature for 4 hours. The solids were then collected and washed with water (4x) by centrifugation, before drying at 50C overnight under vacuum. Finally, the dried material was calcined at 300C with a ramp rate of 10C/min for 4 hours, with a final purple colour.