Gold nanostars for cancer cell-targeted SERS-imaging and NIR light-triggered plasmonic photothermal therapy (PPTT) in the first and second biological windows

Cancer cell-targeted imaging and efficient therapy are vital for tumor diagnosis and treatments. However, the development of multifunctional plasmonic nanoparticles with high-performance SERS-imaging and NIR light-triggered plasmonic photothermal therapy (PPTT) of cancer cells in both the first (NIR-I) and second (NIR-II) biological windows is still a big challenge. In the present work, gold nanostars which possess a broad NIR absorption band covering the NIR-I and NIR-II windows with good NIR SERS activity and photothermal effects were synthesized by a seed-mediated growth method, using gold chloride (HAuCl4), ascorbic acid (AA) and (1-hexadecyl) trimethylammonium chloride (CTAC) as growth solutions. The gold nanostars were further designed to be multifunctional nanoagents by labeling Raman molecules and then conjugating arginine-glycine-aspartic acid (RGD), which can serve as cancer cell-targeted SERS-imaging tags and photothermal nanoagents in both the NIR-I and NIR-II windows. The investigation of in vitro SERS-mapping and PPTT of the A549 human lung adenocarcinoma cells indicates that the proposed multifunctional gold nanostars have great potential for a wide spectrum of light-mediated applications, such as optical imaging and image-guided phototherapy in both the NIR-I and NIR-II biological windows.