Smart Cargo Delivery System based on Mesoporous Nanoparticles for Bone Disease Diagnosis and Treatment

Bone diseases constitute a major issue for modern societies as a consequence of progressive aging. Advantages such as open mesoporous channel, high specific surface area, ease of surface modification, and multifunctional integration are the driving forces for the application of mesoporous nanoparticles (MNs) in bone disease diagnosis and treatment. To achieve better therapeutic effects, it is necessary to understand the properties of MNs and cargo delivery mechanisms, which are the foundation and key in the design of MNs. The main types and characteristics of MNs for bone regeneration, such as mesoporous silica (mSiO2 ), mesoporous hydroxyapatite (mHAP), mesoporous calcium phosphates (mCaPs) are introduced. Additionally, the relationship between the cargo release mechanisms and bone regeneration of MNs-based nanocarriers is elucidated in detail. Particularly, MNs-based smart cargo transport strategies such as sustained cargo release, stimuli-responsive (e.g., pH, photo, ultrasound, and multi-stimuli) controllable delivery, and specific bone-targeted therapy for bone disease diagnosis and treatment are analyzed and discussed in depth. Lastly, the conclusions and outlook about the design and development of MNs-based cargo delivery systems in diagnosis and treatment for bone tissue engineering are provided to inspire new ideas and attract researchers' attention from multidisciplinary areas spanning chemistry, materials science, and biomedicine.

Multifunctional Mesoporous Polydopamine With Hydrophobic Paclitaxel For Photoacoustic Imaging-Guided Chemo-Photothermal Synergistic Therapy

BACKGROUND

Chemo-photothermal therapy has attracted intensive attention because of its low side effects and better therapeutic efficiency. Although many photothermal agents have been loaded with chemotherapeutic drugs for chemo-photothermal therapy, their applications are limited by complex synthetic protocols and long-term safety. Therefore, there is significant clinical value in the development of a simple system of biocompatible and biodegradable photothermal nanomaterials with high payloads of chemotherapeutic drugs for chemo-photothermal synergistic therapy.

MATERIALS AND METHODS

In this study, PEG-modified polydopamine nanoparticles with mesoporous structure (MPDA-PEG) were successfully obtained by an emulsion-induced interface assembly strategy. Subsequently, paclitaxel (PTX) dissolved in acetone was loaded into the mesoporous channels of MPDA-PEG nanoparticles by solution absorption method. A PTX-loaded MPDA-PEG (MPDA-PEG-PTX) nanoplatform for combination of photothermal therapy (PTT) and chemotherapy was developed.

RESULTS

The synthesized MPDA-PEG nanoparticles had a great photothermal effect under near-infrared (NIR) laser irradiation and exhibited an enhanced photothermal effect with the increase of particle size. Meanwhile, MPDA-PEG nanoparticles also had a high payload of PTX, and the PTX release could be greatly accelerated by elevated temperature from photothermal effect. In MTT cytotoxicity assay, A549 cells incubated with MPDA-PEG-PTX under NIR laser irradiation (PTT + chemotherapy group) exhibited better therapeutic effect than single chemotherapy (MPDA-PEG-PTX group) and PTT (MPDA-PEG + Laser group). The synergistic therapeutic effect of MPDA-PEG-PTX with NIR laser irradiation in vivo was further investigated under the guidance of photoacoustic imaging (PAI), tumors of nude mice treated with MPDA-PEG-PTX with NIR laser irradiation were completely eliminated with minimal side effect.

CONCLUSION

The MPDA-PEG-PTX nanoplatform is a simple and effective platform which can completely inhibit tumor growth with minimal side effects under NIR irradiation, and it exhibits better therapeutic effect than single chemotherapy and PTT.