Synthesis Of Spiky Gold Nanostructures And Their Applications In Cancer Multimodal Theranostics

In cancer treatment,conventional surgical resection is difficult to remove completely the tumor,leading to high risk of recurrence and metastasis post-surgery,while radiotherapy and chemotherapy usually cause systemic toxicity with servere damage of body organs,so it is particularly important to find more efficient cancer treatment with less toxicity and side effects.Previous studies have shown that spiky gold nanostructures owing to the plasmonic propertiesnot only have ultra-high detection sensitivity in surface-enhanced Raman scattering(SERS)detection,but also have excellent photothermal performance,so that they hold great potential for high-efficiency cancer theranostics.Spiky gold nanostructures can serve as a reliable multimodal theranostic material for monitoring of cancer cell in vitro,visualization of tumor in vivo,and photothermal therapy.In this paper,spiky gold nanostructures with excellent photothermal properties and good biocompatibility were synthesized by a seed-mediated synthetic route,with various shaped seeds including spherical,cubic and rod-like gold seeds,respectively.The morphology and plasmonic properties of spiky gold nanostructures were manipulated by the seed shape.It is found that spiky gold nanostructures synthesized with spherical gold seeds had the best photothermal performance,while the spiky gold nanostructures synthesized with cubic gold seeds had the highest SERS enhancnement factor.In addition,the spiky gold nanostructures synthesized with rod-like gold seeds dispay a plasmon resonance wavelength of >1000 nm adjustable by the ratio of seed-to-chloroauric acid,which has the potential for the near-infrared II(1000-1700 nm)optical application.The synthesized spiky gold nanostructures were further functionalized to improve their biocompatibility,photothermal imaging ability,and SERS detection for in vivo biomedical applications.Specifically,these spiky gold nanostructures were modified sequentially with p-nitrothiophenol(p-NTP),chitosan(CS),and hyaluronic acid(HA).HA can actively target CD44-overexpressed triple-negative breast cancer cells 4T1 used in this work,thereby enhancing the tumor accumulationand reducing damage to normal tissues.In vivo experiments showed that the spiky gold nanostructures synthesized with spherical gold seeds had the best photothermal therapy performance,followed by thst from cubic gold seeds and then from rod-like gold seeds.Studies have shown that these spiky gold nanostructures not only have good photothermal therapeutic performance,but also can be used for photothermal imaging and SERS imaging to monitor the tumor.The present work provides a reliable scheme for efficient cancer treatment and therapeutic monitoring of cancer.