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. Author manuscript; available in PMC: 2009 Jun 29.
Published in final edited form as: J Am Chem Soc. 2009 Jun 10;131(22):7540–7541. doi: 10.1021/ja902226z

Figure 1.

Figure 1

Schematic diagrams showing the structure, preparation, and pH-responsive behavior of smart SERS nanoparticles. (a) Molecular structure of pH-induced conformational changes of a thiolated block copolymer consisting of a pH-responsive ploymethacrylic acid (PMAA) block (MW 3000), an amphiphilic polyethylene glycol (PEG) block (MW 5000), and a terminal lipoic acid (LA) anchoring group. (b) Preparation of dye-encoded gold nanoparticle with SERS and stimuli-responsive properties. (c) Nanoparticle aggregation induced by polymer conformational changes, leading to plasmonic coupling and SERS. Each gold particle (60 nm) was tagged with ∼1,000 reporter molecules (such as organic dyes) and was encapsulated with ∼104 LA-PEG-PMAA copolymer molecules.