Triphase interface synthesis of plasmonic gold bellflowers as near-infrared light mediated acoustic and thermal theranostics.

We present a novel gold bellflower (GBF) platform with multiple-branched petals, prepared by a liquid-liquid-gas triphase interface system, for photoacoustic imaging (PAI)-guided photothermal therapy (PTT). Upon near-infrared (NIR) laser irradiation, the GBFs, with strong NIR absorption, showed very strong PA response and an ultrahigh photothermal conversion efficiency (η, ∼74%) among the reported photothermal conversion agents. The excellent performance in PAI and PTT is mainly attributed to the unique features of the GBFs: (i) multiple-branched petals with an enhanced local electromagnetic field, (ii) long narrow gaps between adjacent petals that induce a strong plasmonic coupling effect, and (iii) a bell-shaped nanostructure that can effectively amplify the acoustic signals during the acoustic propagation. Besides the notable PTT and an excellent PAI effect, the NIR-absorbing GBFs may also find applications in NIR light-triggered drug delivery, catalysis, surface enhanced Raman scattering, stealth, antireflection, IR sensors, telecommunications, and the like.

An aptamer-targeting photoresponsive drug delivery system using "off-on" graphene oxide wrapped mesoporous silica nanoparticles.

We have developed a novel aptamer-targeting photoresponsive drug delivery system by non-covalent assembly of a Cy5.5-AS1411 aptamer conjugate on the surface of graphene oxide wrapped doxorubicin (Dox)-loaded mesoporous silica nanoparticles (MSN-Dox@GO-Apt) for light-mediated drug release and aptamer-targeted cancer therapy. The two "off-on" switches of the MSN-Dox@GO-Apt were controlled by aptamer targeting and light triggering, respectively. The Cy5.5-AS1411 ligand provides MSN-Dox@GO-Apt with nucleolin specific targeting and real-time indicator abilities by "off-on" Cy5.5 fluorescence recovery. The GO acts as a gatekeeper to prevent the loaded Dox from leaking in the absence of laser irradiation, and to control the Dox release in response to laser irradiation. When the GO wrapping falls off upon laser irradiation, the "off-on" photoresponsive drug delivery system is activated, thus inducing chemotherapy. Interestingly, with an increase in laser power, the synergism of chemotherapy and photothermal therapy in a single MSN-Dox@GO-Apt platform led to much more effective cancer cell killing than monotherapies, providing a new approach for treatment against cancer.

PET and NIR optical imaging using self-illuminating (64)Cu-doped chelator-free gold nanoclusters.

Self-illuminating fluorescence imaging without autofluorescence background interference has recently aroused more research interests in molecular imaging. Currently, only a few self-illuminating probes were developed, based mainly on toxic quantum dots such as CdSe, CdTe. Herein, we report a novel design of nontoxic self-illuminating gold nanocluster ((64)Cu-doped AuNCs) for dual-modality positron emission tomography (PET) and near-infrared (NIR) fluorescence imaging based on Cerenkov resonance energy transfer (CRET). PET radionuclide (64)Cu was introduced by a chelator-free doping method, which played dual roles as the energy donor and the PET imaging source. Meanwhile, AuNCs acted as the energy acceptor for NIR fluorescence imaging. (64)Cu-doped AuNCs exhibited efficient CRET-NIR and PET imaging both in vitro and in vivo. In a U87MG glioblastoma xenograft model, (64)Cu-doped AuNCs showed high tumor uptake (14.9 %ID/g at 18 h) and produced satisfactory tumor self-illuminating NIR images in the absence of external excitation. This self-illuminating nanocluster with non-toxicity and good biocompatibility can be employed as a novel imaging contrast agent for biomedical applications, especially for molecular imaging.

Dye-loaded ferritin nanocages for multimodal imaging and photothermal therapy.

Multimodal imaging-guided photothermal therapy (PTT), for the therapy of cancer, based on a ferritin (FRT) nanocage loaded with the near-infrared dye IR820 (designated DFRT) is demonstrated. The dual roles of DFRT (in imaging and PTT) are successfully balanced by using two different excitation wavelengths: 550 nm for high quantum-yield fluorescence imaging on the one hand and 808 nm for photoacoustic imaging and PTT with high photothermal conversion efficiency on the other.