Dual-Photosensitizer Nanoplatform Based on Near-Infrared Excitation Orthogonal Emission Nanomaterials for Enhanced Photodynamic Therapy of Tumors

Photodynamic therapy (PDT) is considered as a promising therapeutic approach for clinical cancer treatment. However, the hypoxia of the tumor microenvironment leads to the low effect of single PDT. Here, a dual-photosensitizer nanoplatform based on near-infrared excitation orthogonal emission nanomaterials is constructed by introducing two kinds of photosensitizers into the nanosystem. Orthogonal emission upconversion nanoparticles (OE-UCNPs) were used as light conversion reagents to generate red emission under 980 nm irradiation and green emission under 808 nm irradiation. On the one hand, merocyanine 540 (MC540) is introduced as a photosensitizer (PS), which can absorb green light to generate reactive oxygen species (ROS) and trigger PDT for tumor treatment. On the other hand, another photosensitizer, chlorophyll a (Chla), which can be excited by red light, has also been introduced into the system to build a dual PDT nanotherapeutic platform. The introduction of photosensitizer Chla can synergistically increase ROS concentration to accelerate cancer cell apoptosis. Our research shows that this dual PDT nanotherapeutic platform combined with Chla has better therapeutic effects and effectively destroys cancer.

Polysaccharide/mesoporous silica nanoparticle-based drug delivery systems: A review

Mesoporous silica nanoparticles (MSNs) have been well-researched in the design and fabrication of advanced drug delivery systems (DDSs) due to their advantages such as good biocompatibility, large specific surface area and pore volume for drug loading, easily surface modification, adjusted size and good thermal/chemical stability. For MSN-based DDSs, gate materials are also necessary. And natural polysaccharides, one kind of the most abundant natural resource, have been widely applied as the "gatekeepers" in MSN-based DDSs. Polysaccharides are cheap and rich in sources with good biocompatibility, and some of them have important biological functions. In this review article, polysaccharides including chitosan, hyaluronic acid, sodium alginate and dextran, et al. are briefly introduced. And the preparation processes and properties such as controlled drug release, cancer targeting and disease diagnosis of functional polysaccharide/MSN-based DDSs are discussed.

Construction of a near-infrared responsive upconversion nanoplatform against hypoxic tumors via NO-enhanced photodynamic therapy

Photodynamic therapy (PDT) has been extensively used to treat cancer and other malignant diseases because it can offer many unique advantages over other medical treatments such as less invasive, fewer side effects, lower cost, etc. Despite great progress, the efficiency of PDT treatment, as an oxygen-dependent therapy, is still limited by the hypoxic microenvironment in the human tumor region. In this work, we have developed a near-infrared (NIR) activated theranostic nanoplatform based on upconversion nanoparticles (UCNPs), which incorporates PDT photosensitizer (curcumin) and NO donor (Roussin's black salt) in order to overcome hypoxia-associated resistance by reducing cellular respiration with NO presence in the PDT treatment. Our results suggest that the photo-released NO upon NIR illumination can greatly decrease the oxygen consumption rate and hence increase singlet oxygen generation, which ultimately leads to an increased number of cancer cell deaths, especially under hypoxic condition. It is believed that the methodology developed in this study enables to relieve the hypoxia-induced resistance in PDT treatment and also holds great potential for overcoming hypoxia challenges in other oxygen-dependent therapies.

Gold nanostructures for the sensing of pH using a smartphone

Recently, metal nanostructures have been found to be capable of recognizing small changes in their surrounding environment, which can be utilized as significant sensing tools. In this study, we demonstrated colorimetric sensing of pH by gold nanostructures (GNs) using a simple smartphone. An indigenously developed Android app based on the CIELab 1931 analysis, which could run in a smartphone, was used for the precise determination of the pH value of liquid media. The pH value of an unknown solution obtained from the developed Android app was also compared with that obtained from the conventional ratiometric technique and a commercial pH meter. In another endeavor, it was found that the synthesized GNs demonstrated a high energy transfer efficiency from a donor (namely, the rhodamine 6G, (Rh 6G)) dye. This property of the GNs can be utilized further in the future for studying different bimolecular activities within the human body. It was found that the photoluminescence (PL) of Rh 6G was quenched when it was kept in the vicinity of the synthesized GNs, which was explained in terms of the Förster energy transfer mechanism. Thus, the present study will open up a plethora of opportunities for researchers to employ the nanostructures of gold and other metals in developing low-cost and Internet of Things (IoT)-based sensing devices using only a smart phone.

Near-Infrared Excited Orthogonal Emissive Upconversion Nanoparticles for Imaging-Guided On-Demand Therapy

Photodynamic therapy (PDT) has been considered as a promising and noninvasive strategy for clinical cancer treatment. Nonetheless, building a smart "off-on" theranostic PDT platform to spatiotemporally control the generation of reactive oxygen species in the PDT treatment still remains challenging. Here, we have rationally developed photoswitching upconversion nanoparticles (UCNPs) with orthogonal emissive properties in response to two distinct near-infrared (NIR) emissions at 808 and 980 nm, i.e., red emission with 980 nm excitation and green emission with 808 nm excitation. Unlike traditional photoswitching UCNPs, these specially designed core-shell-shell structured UCNPs do not require complicated multilayer doping as their red and green upconversion luminescence both originate from the same activator Er³⁺ ions in the core structure. As a proof of concept, we have demonstrated the capability of these orthogonal emissive UCNPs for imaging-guided PDT in a real-time manner, where the red emission excited by 980 nm light is used to trigger PDT and the green emission with 808 nm excitation is to diagnose and monitor the therapeutic treatment. Our study suggests that such specially designed UCNPs with orthogonal emissions hold great promise for NIR light-targeted and imaging-guided therapy under precisely spatiotemporal control.

Diverse gatekeepers for mesoporous silica nanoparticle based drug delivery systems

Progress on the design of diverse gatekeepers for mesoporous silica nanoparticle based drug delivery systems is summarized.

Cytotoxicity of multifunctional surfactant containing capped mesoporous silica nanoparticles

This paper reports the synthesis of silica capped surfactant (CTAB) and dye (Rose Bengal; RB) containing mesoporous silica nanoparticles (MSNs).

A soft–hard template approach towards hollow mesoporous silica nanoparticles with rough surfaces for controlled drug delivery and protein adsorption

Novel hollow mesoporous silica nanoparticles (HMSNs) with rough surfaces have been successfully prepared using a facile soft–hard template route.

One-pot synthesis of ordered mesoporous silica encapsulated polyoxometalate-based ionic liquids induced efficient desulfurization of organosulfur in fuel

Reaction procedure of desulfurization system.

Inorganic nanoparticles engineered to attack bacteria

Antibiotics delivered to bacteria using engineered nanoparticles (NP), offer a powerful and efficient means to kill or control bacteria, especially those already resistant to antibiotics.

MSN anti-cancer nanomedicines: chemotherapy enhancement, overcoming of drug resistance, and metastasis inhibition

In the anti-cancer war, there are three main obstacles resulting in high mortality and recurrence rate of cancers: the severe toxic side effect of anti-cancer drugs to normal tissues due to the lack of tumor-selectivity, the multi-drug resistance (MDR) to free chemotherapeutic drugs and the deadly metastases of cancer cells. The development of state-of-art nanomedicines based on mesoporous silica nanoparticles (MSNs) is expected to overcome the above three main obstacles. In the view of the fast development of anti-cancer strategy, this review highlights the most recent advances of MSN anti-cancer nanomedicines in enhancing chemotherapeutic efficacy, overcoming the MDR and inhibiting metastasis. Furthermore, we give an outlook of the future development of MSNs-based anti-cancer nanomedicines, and propose several innovative and forward-looking anti-cancer strategies, including tumor tissue-cell-nuclear successionally targeted drug delivery strategy, tumor cell-selective nuclear-targeted drug delivery strategy, multi-targeting and multi-drug strategy, chemo-/radio-/photodynamic-/ultrasound-/thermo-combined multi-modal therapy by virtue of functionalized hollow/rattle-structured MSNs.

A novel pH-controlled immunosensor using hollow mesoporous silica and apoferritin combined system for target virus assay

A novel pH-controlled immunosensor using hollow mesoporous silica and apoferritin combined system has been reported for the first time. The goal of this study was to introduce more electroactive probes into the electrochemical immunosensor. Under such background, we focused our attention on hollow mesoporous silica and apoferritin, both of which have admirable accommodating performances and can be applied for encapsulating electroactive probes. Based on the pH-controlled disassociation-reconstitution process of apoferritin and the mesoporous channels of silica, after the appropriate chemical modification, apoferritin could be fabricated with silica. The results showed that the hollow mesoporous silica and apoferritin combined system was successfully assembled. The excellent performance of the combined system can be applied for ultrasensitive detection of a target virus.

Advanced materials for co-delivery of drugs and genes in cancer therapy

With cancer being the major cause of mortality worldwide, the continued development of safe and efficacious treatments is warranted. A better understanding of the molecular mechanism and genetic basis of tumor initiation and progression, coupled with advances in chemistry, molecular biology and engineering have led to discovery of a wide range of therapeutic agents for cancer therapy. However, multidrug-resistance, which is mainly caused by malfunction of genes, has become a major problem in chemotherapy. To overcome this problem, the simultaneous delivery of genes to cancer cells has been proposed to correct the malfunctioned genes to sensitize the cells to chemotherapeutics. This progress report summarizes key advances in drug and gene delivery with focus on the development of polymers, peptides, liposomes and inorganic materials as nanocarriers for co-delivery of small molecular drugs and macromolecular genes or proteins. In addition, challenges and future perspectives in the design of nanocarriers for the co-delivery of therapeutic drugs and genes are discussed.

Mesoporous carbon@silicon-silica nanotheranostics for synchronous delivery of insoluble drugs and luminescence imaging

A hierarchical theranostic nanostructure with carbon and Si nanocrystals respectively encapsulated in the mesopores and within the framework of mesoporous silica nanoparticles (CS-MSNs) was constructed by a bottom-up self-assembly strategy combining an in situ one-step carbonization/crystallization approach. CS-MSNs exhibited narrow size distribution, high payload of insoluble drugs and unique NIR-to-Vis luminescence imaging feature. The bio-conjugated CS-MSNs with a PEGylated phospholipid compound and hyaluronic acid showed excellent dispersivity and could specifically target cancer cells overexpressing CD44, deliver insoluble drugs into these cells and consequently kill them effectively, and also fluorescently image them simultaneously in a unique and attractive NIR-to-Vis luminescence imaging fashion, providing a promising opportunity for cancer theranostics.