Anisotropic and Amphiphilic Mesoporous Core-Shell Silica Microparticles Provide Chemically Selective Environments for Simultaneous Delivery of Curcumin and Quercetin

Porous silica materials are often used for drug delivery. However, systems for simultaneous delivery of multiple drugs are scarce. Here we show that anisotropic and amphiphilic dumbbell core-shell silica microparticles with chemically selective environments can entrap and release two drugs simultaneously. The dumbbells consist of a large dense lobe and a smaller hollow hemisphere. Electron microscopy images show that the shells of both parts have mesoporous channels. In a simple etching process, the properly adjusted stirring speed and the application of ammonium fluoride as etching agent determine the shape and the surface anisotropy of the particles. The surface of the dense lobe and the small hemisphere differ in their zeta potentials consistent with differences in dye and drug entrapment. Confocal Raman microscopy and spectroscopy show that the two polyphenols curcumin (Cur) and quercetin (QT) accumulate in different compartments of the particles. The overall drug entrapment efficiency of Cur plus QT is high for the amphiphilic particles but differs widely between Cur and QT compared to controls of core-shell silica microspheres and uniformly charged dumbbell microparticles. Furthermore, Cur and QT loaded microparticles show different cancer cell inhibitory activities. The highest activity is detected for the dual drug loaded amphiphilic microparticles in comparison to the controls. In the long term, amphiphilic particles may open up new strategies for drug delivery.

Recent Advances in Mesoporous Silica Nanoparticles for Targeted Drug Delivery applications

Nanotechnology provides the means to design and fabricate delivery vehicles capable of overcoming physiologically imposed obstacles and undesirable side effects of systemic drug delivery. This protocol allows maximal targeting effectiveness and therefore enhances therapeutic efficiency. In recent years, mesoporous silica nanoparticles (MSNPs) have sparked interest in the nanomedicine research community, particularly for their promising applications in cancer treatment. The intrinsic physio-chemical stability, facile functionalization, high surface area, low toxicity, and great loading capacity for a wide range of chemotherapeutic agents make MSNPs very appealing candidates for controllable drug delivery systems. Importantly, the peculiar nanostructures of MSNPs enabled them to serve as an effective drug, gene, protein, and antigen delivery vehicle for a variety of therapeutic regimens. For these reasons, in this review article, we underscore the recent progress in the design and synthesis of MSNPs and the parameters influencing their characteristic features and activities. In addition, the process of absorption, dissemination, and secretion by injection or oral management of MSNPs are also discussed, as they are key directions for the potential utilization of MSNPs. Factors influencing the in vivo fate of MSNPs will also be highlighted, with the main focus on particle size, morphology, porosity, surface functionality, and oxidation. Given that combining other functional materials with MSNPs may increase their biological compatibility, monitor drug discharge, or improve absorption by tumor cells coated MSNPs; these aspects are also covered and discussed herein.

Oral Curcumin via Hydrophobic Porous Silicon Carrier: Preparation, Characterization, and Toxicological Evaluation In Vivo

Curcumin has antioxidant, anti-inflammatory, antimicrobial, and anticarcinogenic activities. However, the clinical application of curcumin has been restricted by the poor water solubility and low bioavailability of this molecule. In this work, hydrophobic porous silicon (pSi) particles were prepared by electrochemical etching method and grafted with the different hydrophobic groups on their surfaces. The loading efficiency of curcumin in pSi has been investigated. The properties of pSi particles have been characterized by scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FTIR). The highest loading efficiency of curcumin can be obtained with pSi surface modified with the octadecyl silane group. The release properties of curcumin in hydrophobic pSi have been researched in vitro and in vivo. The curcumin in the hydrophobic pSi surface keeps a high antioxidant bioactivity. The toxicological evaluation of the hydrophobic pSi particles indicates they have a high in vivo biocompatibility within the observed dose ranges. The hydrophobic pSi particles could provide an effective and controlled release delivery carrier for curcumin, which may provide a new tool platform for the further development of curcumin.

Recent Progress in Micro/Nanoreactors toward the Creation of Artificial Organelles

Artificial organelles created from a bottom up approach are a new type of engineered materials, which are not designed to be living but, instead, to mimic some specific functions inside cells. By doing so, artificial organelles are expected to become a powerful tool in biomedicine. They can act as nanoreactors to convert a prodrug into a drug inside the cells or as carriers encapsulating therapeutic enzymes to replace malfunctioning organelles in pathological conditions. For the design of artificial organelles, several requirements need to be fulfilled: a compartmentalized structure that can encapsulate the synthetic machinery to perform an enzymatic function, as well as a means to allow for communication between the interior of the artificial organelle and the external environment, so that substrates and products can diffuse in and out the carrier allowing for continuous enzymatic reactions. The most recent and exciting advances in architectures that fulfill the aforementioned requirements are featured in this review. Artificial organelles are classified depending on their constituting materials, being lipid and polymer-based systems the most prominent ones. Finally, special emphasis will be put on the intracellular response of these newly emerging systems.

Rational design of curcumin loaded multifunctional mesoporous silica nanoparticles to enhance the cytotoxicity for targeted and controlled drug release

Curcumin has attracted increasing attentions in recent years due to its promising anticancer activities. However, the hydrophobicity of curcumin has limited greatly its efficacy in clinical trials. In this study, folate (FA)-receptor targeting mesoporous silica nanoparticles that promise high loadings of curcumin via pH-sensitive Schiff base reactions were constructed and examined for targeted delivery of curcumin. Such nano-delivery system showed significantly improved stability and biocompatibility of curcumin under physiological conditions. Further investigations demonstrated that this nanocarrier had high values of drug loading efficiency (9.5%) and pH-responsive drug release property. Moreover, the particles could be efficiently internalized by FA-receptor-rich MCF-7 cells through the receptor-mediated endocytosis, whereas FA-receptor-poor HEK-293T normal cells showed much lower endocytosis of the nanoparticles under the same conditions. The in vitro cytotoxicity assay indicated that the curcumin-loaded nanoparticles exhibited significantly enhanced cytotoxicity against MCF-7 cell than HEK-293T cells because of the higher cellular uptake efficiency of nanocarriers. More broadly, this work demonstrates a new type of mesoporous silica nanocarrier particularly useful for targeted and controlled drug release applications.

Control of Mechanical Stability of Hollow Silica Particles, and Its Measurement by Mercury Intrusion Porosimetry

Hollow silica particles (HSPs) have become the focus of interest in many laboratories recently, because of their versatility, stemming from the ability to control their size and shape, as well as surface functionalization. Determining the mechanical stability of hollow particles is essential for their use, both in applications in which they need to retain their structure, as well as those in which they need to break down. We have synthesized a series of HSPs (inner diameter of 231 nm) with increasing wall thickness (7-25 nm), using a template approach. Their mechanical stability was measured using mercury intrusion porosimetry (MIP), which represents the novel application of the technique for these materials. The samples with complete shells break at progressively higher pressures, and samples with wall thickness ≥21 nm remain stable to the highest pressure applied (414 MPa). Other characterization methods, namely microscopy, gas adsorption, and small-angle X-ray scattering, shed light on the size parameters of the particles, as well as the porosity of the silica walls. By varying the amount of silica precursor used in the template coating step, we were able to produce hollow silicas with variable stability, thereby allowing for control of their mechanical properties.

Curcumin as a multifaceted compound against human papilloma virus infection and cervical cancers: A review of chemistry, cellular, molecular, and preclinical features

Curcumin, the bioactive polyphenolic ingredient of turmeric, has been extensively studied for its effects on human papilloma virus (HPV) infection as well as primary and malignant squamous cervical cancers. HPV infections, especially those related to HPV 16 and 18 types, have been established as the leading cause of cervical cancer; however, there are also additional contributory factors involved in the etiopathogenesis of cervical cancers. Curcumin has emerged as having promising chemopreventive and anticancer effects against both HPV-related and nonrelated cervical cancers. In this review, we first discuss the biological relevance of curcumin and both its pharmacological effects and pharmaceutical considerations from a chemical point of view. Next, the signaling pathways that are modulated by curcumin and are relevant to the elimination of HPV infection and treatment of cervical cancer are discussed. We also present counter arguments regarding the effects of curcumin on signaling pathways and molecular markers dysregulated by benzo(a)pyrene (Bap), a carcinogen found in pathological cervical lesions of women who smoke frequently, and estradiol, as two important risk factors involved in persistent HPV-infection and cervical cancer. Finally, various strategies to enhance the pharmacological activity and pharmacokinetic characteristics of curcumin are discussed with examples of studies in experimental models of cervical cancer. © 2016 BioFactors, 43(3):331-346, 2017.

Curcumin-Loaded Amine-Functionalized Mesoporous Silica Nanoparticles Inhibit α-Synuclein Fibrillation and Reduce Its Cytotoxicity-Associated Effects

This study aimed to develop a drug carrier based on amine-functionalized mesoporous silica nanoparticles (AAS-MSNPs) for a poorly water-soluble drug, curcumin (CUR), and to study its effects on α-synuclein (α-Syn) fibrillation and cytotoxicity. Here, we show that AAS-MSNPs possess high values of loading efficiency and capacity (33.5% and 0.45 mg drug/mg MSNPs, respectively) for CUR. It is also revealed that α-Syn species interact strongly with the CUR-loaded AAS-MSNPs, leading to a significant inhibition of the fibrillation process. Furthermore, these samples reduce the toxic effects of CUR. However, drug-loaded AAS-MSNPs do not affect the cytotoxic properties of the formed fibrils considerably. In addition, CUR loaded onto AAS-MSNPs shows enhanced stability in comparison with that of the free drug. These remarkable properties introduce AAS-MSNPs as a promising tool for the formulation of poorly water-soluble drugs such as CUR.

Rational Design of Multifunctional Dendritic Mesoporous Silica Nanoparticles to Load Curcumin and Enhance Efficacy for Breast Cancer Therapy

Breast cancer is the primary reason for cancer-related death in women worldwide and the development of new formulations to treat breast cancer patients is crucial. Curcumin (Cur), a natural product, exerts promising anticancer activities against various cancer types. However, its therapeutic efficacy is hindered as a result of poor water solubility, instability, and low bioavailability. The aim of this work is to assess the curative effect of a novel nanoformulation, i.e., Cur-loaded and calcium-doped dendritic mesoporous silica nanoparticles modified with folic acid (Cur-Ca@DMSNs-FA) for breast cancer therapy. The results manifested that Cur-Ca@DMSNs-FA dispersed very well in aqueous solution, released Cur with a pH-responsible profile, and targeted efficiently to human breast cancer MCF-7 cells. Further investigations indicated that Cur-Ca@DMSNs-FA effectively inhibited cell proliferation, increased intracellular ROS generation, decreased mitochondrial membrane potential, and enhanced cell cycle retardation at G2/M phase, leading to a higher apoptosis rate in MCF-7 compared to free Cur. Moreover, the Western blotting analysis demonstrated that Cur-Ca@DMSNs-FA were more active than free Cur through suppression of PI3K/AKT/mTOR and Wnt/β-catenin signaling, and activation of the mitochondria-mediated apoptosis pathway. In addition, hemolysis assay showed that the Ca@DMSNs-FA exhibited good biocompatibility. Last, in vivo studies indicated that when Cur was encapsulated in Ca@DMSNs-FA, the Cur concentration in blood serum and tumor tissues was increased after 1 h intraperitoneal injection. In conclusion, Cur-Ca@DMSNs-FA might act as a potential anticancer drug formulation for breast cancer therapy.

Exploring the use of nanocarrier systems to deliver the magical molecule; Curcumin and its derivatives

Curcumin and its derivatives; curcuminoids have been proven as potential remedies in different diseases. However, their delivery carries several challenges owing to their poor aqueous solubility, photodegradation, chemical instability, poor bioavailability and rapid metabolism. This review explores and criticizes the numerous attempts that were adopted through the years to entrap/encapsulate this valuable drug in nanocarriers aiming to reach its most appropriate and successful delivery system.

Novel drug delivery nanosystems based on out-inside bifunctionalized mesoporous silica yolk–shell magnetic nanostars used as nanocarriers for curcumin

Bifunctionalized yolk–shell magnetic mesoporous silica is used as a curcumin nanocarrier with magnetic response and increased cellular uptake.

Self-carried curcumin nanoparticles for in vitro and in vivo cancer therapy with real-time monitoring of drug release

The use of different nanocarriers for delivering hydrophobic pharmaceutical agents to tumor sites has garnered major attention. Despite the merits of these nanocarriers, further studies are needed to improve their drug loading capacities (which are typically <10%) and reduce their potential systemic toxicity. Therefore, the development of alternative self-carried nanodrug delivery strategies without using inert carriers is highly desirable. In this study, we developed a self-carried curcumin (Cur) nanodrug for highly effective cancer therapy in vitro and in vivo with real-time monitoring of drug release. With a biocompatible C18PMH-PEG functionalization, the Cur nanoparticles (NPs) showed excellent dispersibility and outstanding stability in physiological environments with drug loading capacities >78 wt%. Both confocal microscopy and flow cytometry confirmed the cellular fluorescence "OFF-ON" activation and real-time monitoring of the Cur molecule release. In vitro and in vivo experiments clearly show that the therapeutic efficacy of the PEGylated Cur NPs is considerably better than that of free Cur. This self-carried strategy with real-time monitoring of drug release may open a new way for simultaneous cancer therapy and monitoring.

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.

The chemistry of curcumin: from extraction to therapeutic agent

Curcumin, a pigment from turmeric, is one of the very few promising natural products that has been extensively investigated by researchers from both the biological and chemical point of view. While there are several reviews on the biological and pharmacological effects of curcumin, chemistry reviews are comparatively scarcer. In this article, an overview of different aspects of the unique chemistry research on curcumin will be discussed. These include methods for the extraction from turmeric, laboratory synthesis methods, chemical and photochemical degradation and the chemistry behind its metabolism. Additionally other chemical reactions that have biological relevance like nucleophilic addition reactions, and metal chelation will be discussed. Recent advances in the preparation of new curcumin nanoconjugates with metal and metal oxide nanoparticles will also be mentioned. Directions for future investigations to be undertaken in the chemistry of curcumin have also been suggested.

Acid-induced release of curcumin from calcium containing nanotheranostic excipient

Poor water solubility is believed one of the most critical problems of numerous promising pharmaceutical ingredients in their successful clinical utilization. Nanomedicine holds considerable promise to address this challenge, because it extends the therapeutic window of hydrophobic drugs through nanonization approach. Recently, the integration of diagnostic agents with smart therapeutic nanocarriers is also an emerging research arena to simultaneously visualize diseased tissues, achieve site specific drug release and track the impact of therapy. In this study, we have developed a biocompatible smart theranostic nanosystem which transports a highly promising hydrophobic drug (curcumin) in response to mildly acidic environment. As calcium is a main constituent of human body, hence we exploited the reversible calcium chelate formation tendency of divalent calcium to load and unload curcumin molecules. Moreover, an emerging T1 contrast agent is also tethered onto the surface of nanocarrier to realize MRI diagnosis application. In-vitro cell experiments revealed a significantly high chemotherapeutic efficiency of curcumin nanoformulation (IC50; 1.67 μg/mL), whereas free curcumin was found ineffective at the corresponding concentration (IC50; 29.72 μg/mL). MR imaging test also validated the performance of resulting system. Our strategy can be extended for the targeted delivery of other hydrophobic pharmaceutical ingredients.

Hollow-structured mesoporous materials: chemical synthesis, functionalization and applications

Hollow-structured mesoporous materials (HMMs), as a kind of mesoporous material with unique morphology, have been of great interest in the past decade because of the subtle combination of the hollow architecture with the mesoporous nanostructure. Benefitting from the merits of low density, large void space, large specific surface area, and, especially, the good biocompatibility, HMMs present promising application prospects in various fields, such as adsorption and storage, confined catalysis when catalytically active species are incorporated in the core and/or shell, controlled drug release, targeted drug delivery, and simultaneous diagnosis and therapy of cancers when the surface and/or core of the HMMs are functionalized with functional ligands and/or nanoparticles, and so on. In this review, recent progress in the design, synthesis, functionalization, and applications of hollow mesoporous materials are discussed. Two main synthetic strategies, soft-templating and hard-templating routes, are broadly sorted and described in detail. Progress in the main application aspects of HMMs, such as adsorption and storage, catalysis, and biomedicine, are also discussed in detail in this article, in terms of the unique features of the combined large void space in the core and the mesoporous network in the shell. Functionalization of the core and pore/outer surfaces with functional organic groups and/or nanoparticles, and their performance, are summarized in this article. Finally, an outlook of their prospects and challenges in terms of their controlled synthesis and scaled application is presented.