Effective Distribution of Gold Nanorods in Ordered Thick Mesoporous Silica: A Choice of Noninvasive Theranostics

Porous silica coated gold nanorod core-shell structures demonstrate a multifunctional role in bioimaging, drug delivery, and cancer therapeutics applications. Here, we address a new approach for effective distribution of gold nanorods (GNRs) in a mesoporous silica (MS) shell, viz., one nanorod in one silica particle (GMS). We have studied that silica coating presents major advantages for the better biocompatibility and stability of GNRs. In this study, two different thicknesses of silica shell over GNRs have been discussed as per the application's need; GNRs in thin silica (11 nm) are fit for phototherapy and bioimaging, whereas thick and porous silica (51 nm) coated gold nanorods are suitable for triggered drug delivery and theranostics. However, effective distribution of GNRs in ordered architecture of thick mesoporous silica (MS, more than 50 nm thickness) with high surface area (more than 1000 m2/g) is not well understood so far. Here, we present methodical investigations for uniform and highly ordered mesoporous silica coating over GNRs with tunable thickness (6 to 51 nm). Judicious identification and optimization of different reaction parameters like concentrations of silica precursor (TEOS, 1.85-43.9 mM), template (CTAB, 0.9-5.7 mM), effect of temperature, pH (8.6-10.8), stirring speed (100-400 rpm), and, most importantly, the mode of addition of TEOS with GNRs have been discussed. Studies with thick, porous silica coated GNRs simplify the highest ever reported surface area (1100 m2/g) and cargo capacity (57%) with better product yield (g/batch). First and foremost, we report a highly scalable (more than 500 mL) and rapid direct deposition of an ordered MS shell around GNRs. These engineered core-shell nanoparticles demonstrate X-ray contrast property, synergistic photothermal-chemotherapeutics, and imaging of tumor cell (96% cell death) due to released fluorescent anticancer drug molecules and photothermal effect (52 °C) of embedded GNRs. A deeper insight into their influence on the architectural features and superior theranostics performances has been illustrated in detail. Hence, these findings indicate the potential impact of individual GMS for image guided combination therapeutics of cancer.

Bovine serum albumin-based and dual-responsive targeted hollow mesoporous silica nanoparticles for breast cancer therapy

Combination therapy is an effective way to alleviate the shortcoming of monotherapy and enhances therapeutic efficacy. Herein, a distinctive hollow mesoporous silica nanoparticle (HMSNs) encapsulated with folic acid-modified bovine serum albumin (BSA-FA), denoted as HBF, was engineered for tumor targeting and dual-responsive release of loaded-therapeutic agents MD (methylene blue (MB) and doxorubicin (DOX)). The BSA molecule as a ''gatekeeper'' prevents premature drug leakage and actively unloads the cargos through BSA detachment in response to intracellular glutathione (GSH). Folic acid (FA) promotes the specific intracellular delivery of the drug to folate receptor (FR)-expressing cancer cells to improve the efficacy of chemo-photodynamic therapy (PDT). In vitro drug release profiles showed that the drug carrier could achieve pH/redox-responsive drug release from MD@HBF owing to the cleavage of the imine bonds between HMSNs-CHO and BSA-FA and BSA intramolecular disulfide bond. Additionally, a series of biological evaluations, such as cell uptake experiments, toxicity experiments, and in vivo therapeutic assays indicated that MD@HBF possesses the features of accurately targeting FR-expressing 4T1 cells to induce cells apoptosis in vitro, exhibits outstanding tumor cell synergistic killing efficiency of chemo-photodynamic therapy (combination index CI = 0.325), and inhibits tumors growth. These results demonstrated that the strategy of combining HMSNs with stimuli-responsive biodegradable protein molecules could provide a new potential direction toward the ''on-demand'' drug release for precision chemo-photodynamic therapy in cancer treatment.

Gold Nanorods: The Most Versatile Plasmonic Nanoparticles

Gold nanorods (NRs), pseudo-one-dimensional rod-shaped nanoparticles (NPs), have become one of the burgeoning materials in the recent years due to their anisotropic shape and adjustable plasmonic properties. With the continuous improvement in synthetic methods, a variety of materials have been attached around Au NRs to achieve unexpected or improved plasmonic properties and explore state-of-the-art technologies. In this review, we comprehensively summarize the latest progress on Au NRs, the most versatile anisotropic plasmonic NPs. We present a representative overview of the advances in the synthetic strategies and outline an extensive catalogue of Au-NR-based heterostructures with tailored architectures and special functionalities. The bottom-up assembly of Au NRs into preprogrammed metastructures is then discussed, as well as the design principles. We also provide a systematic elucidation of the different plasmonic properties associated with the Au-NR-based structures, followed by a discussion of the promising applications of Au NRs in various fields. We finally discuss the future research directions and challenges of Au NRs.

Smart wound dressing for infection monitoring and NIR-triggered antibacterial treatment

Hydrogel-based wound dressings can monitor infection via pH-responsive FRET changes and provide on-demand antibacterial treatment via NIR-triggered antibiotic release.

Functional Mesoporous Silica Nanocomposites: Biomedical applications and Biosafety

The rise and development of nanotechnology has enabled the creation of a wide number of systems with new and advantageous features to treat cancer. However, in many cases, the lone application of these new nanotherapeutics has proven not to be enough to achieve acceptable therapeutic efficacies. Hence, to avoid these limitations, the scientific community has embarked on the development of single formulations capable of combining functionalities. Among all possible components, silica-either solid or mesoporous-has become of importance as connecting and coating material for these new-generation therapeutic nanodevices. In the present review, the most recent examples of fully inorganic silica-based functional composites are visited, paying particular attention to those with potential biomedical applicability. Additionally, some highlights will be given with respect to their possible biosafety issues based on their chemical composition.

Dual targeted and pH-responsive gold nanorods with improved chemotherapy and photothermal ablation for synergistic cancer treatment

Cancer is considered to be one of the leading causes of morbidity and mortality worldwide. A multifunctional nanosystem based on gold nanorods (GNRs) has demonstrated the potential to enhance therapeutic performance. In this research, dual-targeted pH-responsive GNRs for synergistic cancer treatment were developed and investigated. The GNRs could target angiogenic endothelial cells in the tumor region using αvβ3-mediated recognition and subsequently facilitate its specific binding to tumor cells mediated via recognition of the folate receptor, which could accumulate precisely at the tumor site. Doxorubicin (DOX) was loaded on to the surface of GNRs via a pH-sensitive hydrazone (hz) bond, which could effectively control the drug release by responding to the tumor acidic microenvironment. In vitro, the FA/RGD-DOX-hz-GNRs showed higher tumor specificity and killing ability under near-infrared irradiation. Furthermore, in B16-F10 xenograft tumor-bearing mice, FA/RGD-DOX-hz-GNRs produced the optimal tumor therapeutic efficacy by antagonizing angiogenesis, inhibiting cell proliferation and causing necrosis. Therefore, the strategy of integration of a photothermal effect, chemotherapy and a molecular active targeting based double-targeting mode appeared advantageous over chemotherapy or a photothermal therapy alone.

A dual-targeted pH-responsive GNR for synergistic cancer treatment was developed and investigated, which demonstrated the desired potential for enhancing therapeutic performance.

Development of poly-2-ethyl-2-oxazoline coated gold-core silica shell nanorods for cancer chemo-photothermal therapy

Aim: Develop a new poly-2-ethyl-2-oxazoline (PEOZ)-based coating for doxorubicin-loaded gold-core mesoporous silica shell (AuMSS) nanorods application in cancer chemo-photothermal therapy. Methods: PEOZ functionalized AuMSS nanorods were obtained through the chemical grafting on AuMSS of a PEOZ silane derivative. Results: The PEOZ chemical grafting on the surface of AuMSS nanorods allowed the neutralization of nanodevices’ surface charge, from -30 to -15 mV, which improved nanoparticles’ biocompatibility, namely by decreasing the blood hemolysis to negligible levels. In vitro antitumoral studies revealed that the combined treatment mediated by the PEOZ-coated AuMSS nanorods result in a synergistic effect, allowing the complete eradication of cervical cancer cells. Conclusion: The application of the PEOZ coating improves the AuMSS nanorods performance as a multifunctional combinatorial therapy for cervical cancer.

Advances in Multicompartment Mesoporous Silica Micro/Nanoparticles for Theranostic Applications

Mesoporous silica nanoparticles (MSNs) are promising functional nanomaterials for a variety of biomedical applications, such as bioimaging, drug/gene delivery, and cancer therapy. This is due to their low density, low toxicity, high biocompatibility, large specific surface areas, and excellent thermal and mechanical stability. The past decade has seen rapid advances in the development of MSNs with multiple compartments. These include hierarchical porous structures and core-shell, yolk-shell, and Janus structured particles for efficient diagnosis and therapeutic applications. We review advances in this area, covering the categories of multicompartment MSNs and their synthesis methods, with an emphasis on hierarchical structures and the incorporation of multiple functions. We classify multicompartment mesoporous silica micro/nanostructures, ranging from core-shell and yolk-shell structures to Janus and raspberry-like nanoparticles, and discuss their synthesis methods. We review applications of these multicompartment MSNs, including bioimaging, targeted drug/gene delivery, chemotherapy, phototherapy, and in vitro diagnostics. We also highlight the latest trends and new opportunities.

Nanocarrier-Mediated Photochemotherapy and Photoradiotherapy

Photothermal therapy (PTT) and photodynamic therapy (PDT) both utilize light to induce a therapeutic effect. These therapies are rapidly gaining importance due to the noninvasiveness of light and the limited adverse effect associated with these treatments. However, most preclinical studies show that complete elimination of tumors is rarely observed. Combining PDT and PTT with chemotherapy or radiotherapy can improve the therapeutic outcome and simultaneously decrease side effects of these conventional treatments. Nanocarriers can help to facilitate such a combined treatment. Here, the most recent advancements in the field of photochemotherapy and photoradiotherapy, in which nanocarriers are employed, are reviewed.

Thermo- and pH-responsive nano-in-micro particles for combinatorial drug delivery to cancer cells

Drug combinatorial therapy has been gaining the scientific community attention as a suitable approach to increase treatments efficacy and promote cancer eradication. In this study, a new pH- and thermo- responsive carrier was developed by combining doxorubicin-loaded gold-core silica shell nanorods with salicylic acid loaded poly (lactic-co-glycolic acid) based microparticles (NIMPS). The obtained results showed that the drugs and nanorods release could be triggered by the near-infrared (NIR) laser irradiation or by the exposition to an acidic environment. The in vitro 2D cell studies showed that the NIMPS are biocompatible and easily uptaken by HeLa cells. In addition, 3D cell culture models revealed that the NIMPS administration, combined with the NIR laser irradiation, was capable of reducing the size of the HeLa spheroids up to 48%. Overall, the attained data support the application of the nano-in-micro spheres as a dual stimuli responsive drug carrier system for the local administration of combined therapies to cervical cancer cells.

The effect of the shape of gold core–mesoporous silica shell nanoparticles on the cellular behavior and tumor spheroid penetration

Analysis of the effect of shape on the biological performances of gold core–mesoporous silica shell nanoparticles.

Synthesis of mesoporous materials as nano-carriers for an antimalarial drug

An antimalarial drug artesunate (ATS) was encapsulated in both functionalized MCM-41 and ordinary MCM-41 with an excellent loading capacity and sustained release behavior for possible biomedical applications.

DOX-Fe3O4@mSiO2-PO-FA nanocomposite for synergistic chemo- and photothermal therapy

A DOX-Fe₃O₄@mSiO₂-PO-FA nanocomposite based drug delivery system for cancer chemotherapy and photothermal therapy.