Near-infrared Photothermal Properties Research Articles

Preparation of polydopamine-modified celastrol nanosuspension and its anti-liver cancer activity in vitro

Celastrol (CEL) is one of the main effective components of traditional Chinese medicine Tripterygium wilfordii Hook.f, which has high antitumor activity. However, its low solubility and low bioavailability limit its clinical use. In this study, a CEL nanosuspension (PDA@CEL-NS) with near-infrared photothermal properties was prepared. PDA@CEL-NS contained spherical nanoparticles with an average particle size of 189.67 nm, zeta potential of −30.23 mV, and 60.33% drug loading. X-ray diffraction showed that PDA@CEL-NS had an amorphous structure. PDA@CEL-NS had good stability after storage at 4 °C and 37 °C for 30 days, and there was no aggregation or sedimentation in a 5% glucose solution or culture medium. The highly dispersed nanoparticles greatly improved dissolution in vitro, and the cumulative release rate of PDA@CEL-NS over 72 h was as high as 60.10%. It demonstrated both high release and a good sustained-release effect. Cell experiments showed that PDA@CEL-NS had stronger efficacy than CEL-NS or CEL, and the efficacy was further enhanced after laser application. Nuclear rupture and deformation and the induction of apoptosis were potential toxic mechanisms, and they also inhibited cell migration. In conclusion, PDA@CEL-NS is expected to become a nano-drug delivery system for the treatment of cancer.

Gd2O3-mesoporous silica/gold nanoshells: A potential dual T1/T2 contrast agent for MRI-guided localized near-IR photothermal therapy

A promising clinical trial utilizing gold-silica core-shell nanostructures coated with polyethylene glycol (PEG) has been reported for near-infrared (NIR) photothermal therapy (PTT) of prostate cancer. The next critical step for PTT is the visualization of therapeutically relevant nanoshell (NS) concentrations at the tumor site. Here we report the synthesis of PEGylated Gd2O3-mesoporous silica/gold core/shell NSs (Gd2O3-MS NSs) with NIR photothermal properties that also supply sufficient MRI contrast to be visualized at therapeutic doses (≥108 NSs per milliliter). The nanoparticles have r1 relaxivities more than three times larger than those of conventional T1 contrast agents, requiring less concentration of Gd3+ to observe an equivalent signal enhancement in T1-weighted MR images. Furthermore, Gd2O3-MS NS nanoparticles have r2 relaxivities comparable to those of existing T2 contrast agents, observed in agarose phantoms. This highly unusual combination of simultaneous T1 and T2 contrast allows for MRI enhancement through different approaches. As a rudimentary example, we demonstrate T1/T2 ratio MR images with sixfold contrast signal enhancement relative to its T1 MRI and induced temperature increases of 20 to 55 °C under clinical illumination conditions. These nanoparticles facilitate MRI-guided PTT while providing real-time temperature feedback through thermal MRI mapping.

Core-shell iron oxide@stellate mesoporous silica for combined near-infrared photothermia and drug delivery: Influence of pH and surface chemistry

The chemical design of smart nanocarriers, providing in one nanoformulation combined anticancer therapies, still remains a challenge in the field of nanomedicine. Among nanomaterials, iron oxide-based core-shell nanostructures have been already studied for their intrinsic magnetic hyperthermia features that may be coupled with drug delivery. However, despite the great interest today for photo-induced hyperthermia, very few studies investigated the potential of such nanocarriers to combine photothermia and drug delivery. In this work, our aim was to design functional iron oxide@stellate mesoporous silica nanoparticles (denoted IO@STMS NPs) loaded with a drug and able to combine in a same formulation near-infrared (NIR) light induced photothermia with antitumor drug release. Herein, the NIR photothermal properties (SAR, specific absorption rates) of such nanomaterials were quantified for the first time as a function of the laser power and the NP amount. Aside the response to NIR light, the conditions to obtain very high drug loading (drug payloads up to 91 wt%) of the model antitumor drug doxorubicin (DOX) were optimized by varying different parameters, such as the NP surface chemistry (BARE (Si-OH), aminopropylsiloxane (APTES) and isobutyramide (IBAM)) and the pH of the drug impregnation aqueous solution. The drug release study of these core-shell systems in the presence or absence of NIR light demonstrated that the DOX release efficiency is mainly influenced by two parameters: surface chemistry (BARE ≥ IBAM ≥ APTES) and pH (pH 5.5 ≥ pH 6.5 ≥ pH 7.5). Furthermore, the temperature profiles under NIR light are found similar and independent from the pH range, the surface chemistry and the cycle number. Hence, the combination of local photothermia with lysosomal-like pH induced drug delivery (up to 40% release of the loaded drug) with these nanostructures could open the way towards new drug delivery nanoplatforms for nanomedecine applications.