Noble metal nanostructures have been intensively investigated as active substrates for surface-enhanced Raman spectroscopy (SERS) from visible to near-IR wavelengths. However, metal nanoparticle-based SERS analysis in solutions is very challenging due to uncontrollable and irreproducible colloid aggregation. Here we report the templated synthesis of porous gold-silica hybrid microspheres and their application as reusable colloidal SERS substrates. Mesoporous polymer microspheres are synthesized and used as templates for the synthesis of non-aggregated gold nanoparticles, followed by polydopamine-mediated silicification to fabricate mesoporous gold-silica hybrid microspheres. The mesoporous hybrid particles detect crystal violet in the order of 10–8 M and provide the structural durability of the immobilized gold nanoparticles, allowing them to be recycled for repeated SERS analyses for analytes in a solution with the similar sensitivity. This work suggests that the mesoporous gold-silica hybrid microspheres are attractive SERS substrates in terms of reusability, sensitivity, and stability.
Temperature‐responsive hydrogels were fabricated by the photo‐polymerization of bis‐acryloyl poloxamer tri‐block copolymers, and their temperature‐responsive behavior and physiological effect on skin were investigated. For this, poloxamer macromers were prepared by end‐capping both terminal hydroxyl groups of poloxamer tri‐block copolymers with acrylates. They were then photo‐polymerized to generate polymeric hydrogels with structural integrity that allowed excellent stability against dilution in an aqueous environment. The resulting hydrogels exhibited dramatic reversible swelling behavior upon changes in temperature. A demonstration experiment, in which the hydrogels were applied topically to the skin, showed that they shrank rapidly as a result of the increase in temperature, owing to the contact with the skin surface, highlighting their effectiveness for instantaneously moisturizing the skin.
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