Gold nanoparticles were synthesis by a two-phase method (water/toluene) and attached to a solid phase synthesis (SPS) resins. The average diameter of the nanoparticles determined by TEM image analysis was 3.9 +/- 0.3 nm. The SPS resin used was an o-nitrobenzyl based photolabile system. This was first loaded with Fmoc-Cys(Trt)-OH following standard PyBOP protocols. UV-Vis spectroscopy was used to monitor the reaction of the nanoparticle solution with the SPS resin. The bound nanoparticles were released from the SPS resin by exposure to UV light, (lambda=350 nm, intensity=10000 mu W cm(-2)) and shown to reform a stable solution. The nanoparticles were further modified into clusters on the surface of the SPS resin by the addition of pentanedithiol or assembled into nanoparticle dimers by the addition of a 1,3-propanediamine post photolytic release. (c) 2005 Elsevier B.V. All rights reserved.