Title: Putting Nanomaterials to Work for Biomedical Research
Speaker: Prof. Younan Xia (Washington University at St. Louis)
Date & Time: 2009. 12. 3 (Thu) 16:30 p.m.
Place: 창의관 103호
Putting Nanomaterials to Work for Biomedical Research
Younan Xia
Department of Biomedical Engineering, Washington University, St. Louis, MO 63130
(E-mail: xia@biomed.wustl.edu)
Complex nanostructures with novel properties can often be prepared using very simple chemical reactions. For instance, galvanic replacement reaction between silver nanocubes and HAuCl4 in an aqueous solution transforms 10-200 nm silver nanocubes into gold nanoboxes and nanocages (nanoboxes with porous walls). By controlling the molar ratio of silver to HAuCl4, the plasmon peaks of resultant nanostructures can be continuously tuned from the blue (400 nm) to the near infrared (1200 nm). These hollow gold nanostructures are characterized by extraordinarily large cross-sections for both absorption and scattering. Optical measurements indicate that the 35-nm gold nanocage has a scattering cross-section of ~0.810-15 m2 and an absorption cross-section of ~7.310-15 m2; both of them are more than five orders of magnitude larger than those of conventional organic dyes. Exposure of gold nanocages to a camera flash resulted in the instant melting and conversion of gold nanocages into spherical particles due to photothermal heating. Gold nanocages can be easily bioconjugated with antibodies to target any specific cancer cells. This novel class of hollow nanostructures is being developed as both a contrast agent for optical imaging in early-stage detection of cancer and a therapeutic agent for photothermal treatment of cancer, and as nanoscale capsules for targeted drug delivery.
Speaker: Prof. Younan Xia (Washington University at St. Louis)
Date & Time: 2009. 12. 3 (Thu) 16:30 p.m.
Place: 창의관 103호
Putting Nanomaterials to Work for Biomedical Research
Younan Xia
Department of Biomedical Engineering, Washington University, St. Louis, MO 63130
(E-mail: xia@biomed.wustl.edu)
Complex nanostructures with novel properties can often be prepared using very simple chemical reactions. For instance, galvanic replacement reaction between silver nanocubes and HAuCl4 in an aqueous solution transforms 10-200 nm silver nanocubes into gold nanoboxes and nanocages (nanoboxes with porous walls). By controlling the molar ratio of silver to HAuCl4, the plasmon peaks of resultant nanostructures can be continuously tuned from the blue (400 nm) to the near infrared (1200 nm). These hollow gold nanostructures are characterized by extraordinarily large cross-sections for both absorption and scattering. Optical measurements indicate that the 35-nm gold nanocage has a scattering cross-section of ~0.810-15 m2 and an absorption cross-section of ~7.310-15 m2; both of them are more than five orders of magnitude larger than those of conventional organic dyes. Exposure of gold nanocages to a camera flash resulted in the instant melting and conversion of gold nanocages into spherical particles due to photothermal heating. Gold nanocages can be easily bioconjugated with antibodies to target any specific cancer cells. This novel class of hollow nanostructures is being developed as both a contrast agent for optical imaging in early-stage detection of cancer and a therapeutic agent for photothermal treatment of cancer, and as nanoscale capsules for targeted drug delivery.
