Upconverting nanocomposites with combined photothermal and photodynamic effects

Abstract

Lanthanide-doped upconverting nanoparticles (UCNPs) have been studied for diverse biomedical applications due to their inherent ability to convert near-infrared (NIR) excitation light to higher energies (spanning the ultraviolet, visible, and NIR regions). To explore additional functionalities, rational combination with other optically active nanostructures may lead to the development of new multimodal nanoplatforms with theranostic (therapy and diagnostic) capabilities. Here, we develop a nanocomposite consisting of NaGdF:Er, Yb UCNPs, mesoporous silica (SiO), gold nanorods (GNRs) and a photosensitizer, with integrated functionalities including luminescence imaging, photothermal generation, nanothermometry and photodynamic effects. Under 980 nm irradiation, GNRs and UCNPs are simultaneously excited due to the overlap between the surface plasmon resonance of the GNRs and the absorption of the UCNPs leading to plasmonic enhancement of the upconverted luminescence, while concomitantly creating a temperature gradient. The temperature increase can be determined from the intensity ratio of the upconverted green emission of the UCNPs. Finally, a photosensitizer, zinc phthalocyanine, was loaded into the mesoporous SiO. Upon laser irradiation, the upconverted visible light subsequently activates the photosensitizer to release reactive oxygen species. The multifunctional GNR@SiO@UCNPs nanocomposites showed strong luminescence signal when incubated in HeLa cervical cancer cells, making them ideal bioprobes for future theranostic applications.

Lanthanide‐Based Thermometers: At the Cutting‐Edge of Luminescence Thermometry

“…Under 980 nm irradiation, plasmonic and UC NPs are simultaneously excited leading to a plasmonic enhancement of the UC luminescence and a simultaneous temperature increasing. Upon laser irradiation, and after loading a Zn phthalocyanine photosensitizer into the mesoporous SiO 2 , the UC visible light subsequently activates the photosensitizer to release reactive oxygen species …”

Recent Advances of Plasmonic Nanoparticles and their Applications

“…With the modified surface with folic acids, the hybrid structures were tested for the treatment of OECM-1 oral cancer cells via PTT and cell imaging. In 2017, Huang et al [ 63 ] also observed the upconversion emission enhancement and photothermal property in Au NR@SiO 2 @UCNPs nanocomposites with integrated functionalities, including bioimaging and PTT. Meanwhile, the photosensitizer, zinc phthalocyanine (ZnPc), was introduced into the nanocomposite and excited by the visible light generated from the UCNPs, thereby triggering the release of reactive oxygen species for application in the PDT of cancers.…”

Theranostic nanobubble encapsulating a plasmon-enhanced upconversion hybrid nanosystem for cancer therapy

“…Compared with the traditional treatment, NIR-triggered phototherapy produces a trend with non-invasion that can be classified into photothermal therapy (PTT) 9-11 and photodynamic therapy (PDT) 12-16. The nanocomposite is more useful than the single material because the former can be tuned flexibly with multiple applications and different purposes, thereby creating a complete theranostic nanoplatform 17-21. Gold nanorod (AuNR) is commonly used for PTT and show good thermal generation via luminous energy 22.…”