No abstract

A novel multifunctional drug‐delivery platform is developed based on cholesteryl succinyl silane (CSS) nanomicelles loaded with doxorubicin, Fe3O4 magnetic nanoparticles, and gold nanoshells (CDF‐Au‐shell nanomicelles) to combine magnetic resonance (MR) imaging, magnetic‐targeted drug delivery, light‐triggered drug release, and photothermal therapy. The nanomicelles show improved drug‐encapsulation efficiency and loading level, and a good response to magnetic fields, even after the formation of the gold nanoshell. An enhancement for T2‐weighted MR imaging is observed for the CDF‐Au‐shell nanomicelles. These nanomicelles display surface plasmon absorbance in the near‐infrared (NIR) region, thus exhibiting an NIR (808 nm)‐induced temperature elevation and an NIR light‐triggered and stepwise release behavior of doxorubicin due to the unique characteristics of the CSS nanomicelles. Photothermal cytotoxicity in vitro confirms that the CDF‐Au‐shell nanomicelles cause cell death through photothermal effects only under NIR laser irradiation. Cancer cells incubated with CDF‐Au‐shell nanomicelles show a significant decrease in cell viability only in the presence of both NIR irradiation and a magnetic field, which is attributed to the synergetic effects of the magnetic‐field‐guided drug delivery and the photothermal therapy. Therefore, such multicomponent nanomicelles can be developed as a smart and promising nanosystem that integrates multiple capabilities for effective cancer diagnosis and therapy.

Polypyrrole nanoparticles conjugating gadolinium chelates were successfully fabricated for dual-modal magnetic resonance imaging (MRI) and photoacoustic imaging guided photothermal therapy of cancer, from a mixture of pyrrole and pyrrole-1-propanoic acid through a facile one-step aqueous dispersion polymerization, followed by covalent attachment of gadolinium chelate, using polyethylene glycol as a linker. ). After 24 h intravenous injection of Gd-PEG-PPy NPs, the tumor sites exhibited obvious enhancement in both T 1 -weighted MRI intensity and photoacoustic signal compared with that before injection, indicating the effi cient accumulation of Gd-PEG-PPy NPs due to the introduction of the PEG layer onto the particle surface. In addition, tumor growth could be effectively inhibited after treatment with Gd-PEG-PPy NPs in combination with near-infrared laser irradiation. The passive targeting and high MRI/photoacoustic contrast capability of Gd-PEG-PPy NPs are quite favorable for precise cancer diagnosing and locating the tumor site to guide the external laser irradiation for photothermal ablation of tumors without damaging the surrounding healthy tissues. Therefore, Gd-PEG-PPy NPs may assist in better monitoring the therapeutic process, and contribute to developing more effective "personalized medicine," showing great potential for cancer diagnosis and therapy.

The high intensity focused ultrasound (HIFU) and thermosensitive cerasomes (HTSCs) were successfully assembled by employing cerasome-forming lipid (CFL) in combination with the component lipids of conventional low temperature sensitive liposomes (LTSLs) including 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG-2000) and 1-stearoyl-2-hydroxy-sn-glycero-3-phosphocholine (MSPC). The HTSCs showed spherical shape with a mean diameter around 200 nm, exhibiting good biocompatibility. Both hydrophilic and lipophilic drugs can be efficiently encapsulated into HTSCs. In addition, the release rate of HTSCs could be conveniently adjusted by varying the molar ratios of CFL to DPPC. The drug loaded HTSCs showed much longer blood circulation time (half-life >8.50 ± 1.49 h) than conventional LTSLs (0.92 ± 0.17 h). An in vitro study demonstrated that the drug loaded HTSCs are highly stable at 37 °C and show a burst release at 42 °C, providing a capability to act synergistically against tumors. We found that the HTSCs with a proportion of 43.25% of CFL could release more than 90% hydrophilic drugs in 1 min at an elevated temperature of 42 °C generated by HIFU exposure. After intravenous injection of doxorubicin (DOX) loaded HTSCs at 5 mg DOX/kg, followed by double HIFU sonication, the tumor growth of the adenocarcinoma (MDA-MB-231) bearing mice could be significantly inhibited. Therefore, the drug loaded HTSCs combined with HIFU hold great potential for efficient local chemotherapy of cancer due to the ability to deliver high concentration of chemotherapy drugs directly to the tumor, achieve maximum therapeutic efficacy and minimal side effects, and avoid the damage to the healthy tissues caused by systemic administration of drugs.

Porphyrins have been used as pioneering theranostic agents not only for the photodynamic therapy, sonodynamic therapy and radiotherapy of cancer, but also for diagnostic fluorescence imaging, magnetic resonance imaging and photoacoustic imaging. A variety of porphyrins have been developed but very few of them have actually been employed in clinical trials due to their poor selectivity to tumorous tissue and high accumulation rates in the skin. In addition, most porphyrin molecules are hydrophobic and form aggregates in aqueous media. Nevertheless, the use of nanoparticles as porphyrin carriers shows great promise to overcome these shortcomings. Encapsulating or attaching porphyrins to nanoparticles makes them more suitable for tissue delivery because we can create materials with a conveniently specific tissue lifetime, specific targeting, immune tolerance, and hydrophilicity as well as other characteristics through rational design. In addition, various functional components (e.g. for targeting, imaging or therapeutic functions) can be easily introduced into a single nanoparticle platform for cancer theranostics. This review presents the current state of knowledge on porphyrin-loaded nanoparticles for the interwined imaging and therapy of cancer. The future trends and limitations of prophyrin-loaded nanoparticles are also outlined.

This paper reported a core-shell nanotheranostic agent by growing Prussian blue (PB) nanoshells of 3-6 nm around superparamagnetic Fe3O4 nanocores for targeted photothermal therapy of cancer under magnetic resonance imaging (MRI) guidance. Both in vitro and in vivo experiments proved that the Fe3O4@PB core-shell nanoparticles showed significant contrast enhancement for T2-weighted MRI with the relaxivity value of 58.9 mM(-1)·s(-1). Simultaneously, the composite nanoparticles exhibited a high photothermal effect under irradiation of a near-infrared laser due to the strong absorption of PB nanoshells, which led to more than 80% death of HeLa cells with only 0.016 mg·mL(-1) of the nanoparticles with the aid of the magnetic targeting effect. Using tumor-bearing nude mice as the model, the near-infrared laser light ablated the tumor effectively in the presence of the Fe3O4@PB nanoparticles and the tumor growth inhibition was evaluated to be 87.2%. Capabilities of MRI, magnetic targeting, and photothermal therapy were thus integrated into a single agent to allow efficient MRI-guided targeted photothermal therapy. Most importantly, both PB and Fe3O4 nanoparticles were already clinically approved drugs, so the Fe3O4@PB nanoparticles as a theranostic nanomedicine would be particularly promising for clinical applications in the human body due to the reliable biosafety.

Shining light on cancer cells: A cerasomal photosensitizer of high stability and loading efficiency was developed by conjugation of a porphyrin molecule to an organoalkoxysilylated lipid followed by sol–gel and self‐assembly processes (see picture). This nanoformulation showed intrinsic fluorescence and significant damage to tumor cells under photoirradiation.

Curcumin, a polyphenolic compound extracted from Curcuma longa, has drawn attention for its effective bioactivities against ischemia-induced injury. This study aimed to evaluate the neuroprotective effect of curcumin and investigate the underlying mechanism that mediates autophagy and inflammation in an animal model of middle cerebral artery occlusion (MCAO) in rats. Curcumin was delivered to Sprague Dawley male rats at a dose of 200 mg/kg curcumin by intraperitoneal injection 30 min after ischemia-reperfusion (I/R). LY294002, a specific inhibitor of the PI3K/Akt/mTOR pathway, as well as anisomycin, an activator of TLR4/p38/MAPK, was administered by ventricle injection 30 min before MCAO. The same volume of saline was given as a control. Brain infarction and neurological function were determined 24 h post-MCAO. Immunoblotting and immunofluorescence were used to detect alterations in autophagy-relevant proteins Akt, p-Akt, mTOR, p-mTOR, LC3-II, and LC3-I, and inflammation-related proteins TLR4, p-38, p-p38, and IL-1 in the ipsilateral hemisphere. Cerebral I/R injury resulted in significant alterations of LC3-II/LC3-I, IL-1, TLR4, and p-p38. Curcumin in MCAO rats significantly improved brain damage and neurological function by upregulating p-Akt and p-mTOR and downregulating LC3-II/LC3-I, IL-1, TLR4, p-38, and p-p38. However, these protective effects against ischemia could be suppressed when LY294002 or anisomycin was included. Curcumin exerts neuroprotective effects by attenuating autophagic activities through mediating the PI3K/Akt/mTOR pathway, while also suppressing an inflammatory reaction by regulating the TLR4/p38/MAPK pathway. Furthermore, this study indicates that curcumin could be an effective therapy for patients afflicted with ischemia.