Interaction of Cyclodextrins with Amphiphilic Alternating Cooligomers Possessing the Dense Triazole Backbone

The interaction of cyclodextrins (CDs) with structure-controlled polymers is expected to provide significant insights into macromolecular recognition. However, the interaction of CDs with structure-controlled polymers has been an underexamined issue of investigation. Herein, alternating amphiphilic cooligomers (oligoCnAH, where n denotes the carbon number of alkyl groups; n = 4, 8, and 12) were synthesized by copper(I)-catalyzed azide-alkyne cycloaddition polymerization of heterodimers of 4-azido-5-hexynoic acid (AH) derivatives carrying N-alkylamide and t-butyl (tBu) ester side chains, followed by hydrolysis of the tBu ester, to study the interaction of CDs with oligoCnAH by 1H NMR, nuclear Overhauser effect spectroscopy, and pulse-field-gradient spin-echo NMR. These NMR studies indicated that αCD interacted with oligoC4AH, αCD and βCD interacted with oligoC8AH, and all CDs interacted with oligoC12AH. Based on the equilibrium models proposed, the binding constants were evaluated for the binary mixtures, which showed interaction. Comparing the interactions of the CDs/oligoC12AH binary mixtures with those of the binary mixtures of CDs and alternating copolymers of sodium maleate and dodecyl vinyl ether (polyC12M), it is concluded that oligoC12AH forms less stable micelles than does polyC12M presumably because of the lower molecular weight, the hydrophilic amide groups in the side chain, and the longer interval between neighboring C12 groups in oligoC12AH.

Cyclodextrin nanoparticles in targeted cancer theranostics

The field of cancer nanotheranostics is rapidly evolving, with cyclodextrin (CD)-based nanoparticles emerging as a promising tool. CDs, serving as nanocarriers, have higher adaptability and demonstrate immense potential in delivering powerful anti-cancer drugs, leading to promising and specific therapeutic outcomes for combating various types of cancer. The unique characteristics of CDs, combined with innovative nanocomplex creation techniques such as encapsulation, enable the development of potential theranostic treatments. The review here focuses mainly on the different techniques administered for effective nanotheranostics applications of CD-associated complex compounds in the domain of cancer treatments. The experimentations on various loaded drugs and their complex conjugates with CDs prove effective in in vivo results. Various cancers can have potential nanotheranostics cures using CDs as nanoparticles along with a highly efficient process of nanocomplex development and a drug delivery system. In conclusion, nanotheranostics holds immense potential for targeted drug delivery and improved therapeutic outcomes, offering a promising avenue for revolutionizing cancer treatments through continuous research and innovative approaches.

Iron-Based Ceramic Composite Nanomaterials for Magnetic Fluid Hyperthermia and Drug Delivery

Because of the unique physicochemical properties of magnetic iron-based nanoparticles, such as superparamagnetism, high saturation magnetization, and high effective surface area, they have been applied in biomedical fields such as diagnostic imaging, disease treatment, and biochemical separation. Iron-based nanoparticles have been used in magnetic resonance imaging (MRI) to produce clearer and more detailed images, and they have therapeutic applications in magnetic fluid hyperthermia (MFH). In recent years, researchers have used clay minerals, such as ceramic materials with iron-based nanoparticles, to construct nanocomposite materials with enhanced saturation, magnetization, and thermal effects. Owing to their unique structure and large specific surface area, iron-based nanoparticles can be homogenized by adding different proportions of ceramic minerals before and after modification to enhance saturation magnetization. In this review, we assess the potential to improve the magnetic properties of iron-based nanoparticles and in the preparation of multifunctional composite materials through their combination with ceramic materials. We demonstrate the potential of ferromagnetic enhancement and multifunctional composite materials for MRI diagnosis, drug delivery, MFH therapy, and cellular imaging applications.

Cyclodextrin nanoparticles for diagnosis and potential cancer therapy: A systematic review

Cancer is still one of the world’s deadliest health concerns. As per latest statistics, lung, breast, liver, prostate, and cervical cancers are reported topmost worldwide. Although chemotherapy is most widely used methodology to treat cancer, poor pharmacokinetic parameters of anticancer drugs render them less effective. Novel nano-drug delivery systems have the caliber to improve the solubility and biocompatibility of various such chemical compounds. In this regard, cyclodextrins (CD), a group of natural nano-oligosaccharide possessing unique physicochemical characteristics has been highly exploited for drug delivery and other pharmaceutical purposes. Their cup-like structure and amphiphilic nature allows better accumulation of drugs, improved solubility, and stability, whereas CDs supramolecular chemical compatibility renders it to be highly receptive to various kinds of functionalization. Therefore combining physical, chemical, and bio-engineering approaches at nanoscale to specifically target the tumor cells can help in maximizing the tumor damage without harming non-malignant cells. Numerous combinations of CD nanocomposites were developed over the years, which employed photodynamic, photothermal therapy, chemotherapy, and hyperthermia methods, particularly targeting cancer cells. In this review, we discuss the vivid roles of cyclodextrin nanocomposites developed for the treatment and theranostics of most important cancers to highlight its clinical significance and potential as a medical tool.

Nanocarriers for drug-delivery systems using a ureido-derivatized polymer gatekeeper for temperature-controlled spatiotemporal on-off drug release

Accidental chemotherapy extravasation exacerbates the side effects of anticancer drugs. Therefore, drug-delivery nanocarriers should be designed to avoid persistent drug release at off-target sites and promote burst drug release at on-target. Considering these requirements, poly(allylamine)-co-poly(allylurea) (PAU), a ureido-derivatized temperature responsive polymer with upper critical solution temperature (UCSTs), is an ideal material. This report describes the fabrication, characterization, and in vitro cellular toxicity of PAU polymer-grafted magnetic mesoporous silica nanoparticles as drug-delivery nanocarriers. A UCST of 43 °C and an ultranarrow transition temperature range of 39-43 °C was realized, ensuring that the nanocarriers suppressed undesirable leakage to below 10 % of the drug loading for 8 h in the absence of a thermal stimulus. A drug release burst of up to 75 % of the drug loading was achieved within 30 min after the stimulus, reducing the viability of the in vitro cancer cells to 12 %. Therefore, the ureido-derivatized polymer is one of the most suitable gatekeepers for drug-delivery nanocarriers.

Mineral medicine: from traditional drugs to multifunctional delivery systems

Mineral drugs are an important constituent of traditional Chinese medicine (TCM). Taking minerals that contain heavy metals as drugs is a very national characteristic part of TCM. However, the safety and scientific nature of mineral drugs are controversial owing to their heavy metals and strong toxicity. In 2000, the Food and Drug Administration (FDA) authorized arsenic trioxide (ATO) as first-line therapy for acute promyelocytic leukemia. This makes the development and utilization of mineral drugs become a research hotspot. The development of nanomedicine has found a great prospect of mineral drugs in nano-delivery carriers. And that will hold promise to address the numerous biological barriers facing mineral drug formulations. However, the studies on mineral drugs in the delivery system are few at present. There is also a lack of a detailed description of mineral drug delivery systems. In this review, the advanced strategies of mineral drug delivery systems in tumor therapy are summarized. In addition, the therapeutic advantages and research progress of novel mineral drug delivery systems are also discussed. Here, we hope that this will provide a useful reference for the design and application of new mineral drug delivery systems.

Cyclodextrins and inorganic nanoparticles: Another tale of synergy

In this review, we summarize the recent research focused on the combination of inorganic nanoparticles and α-, β- and γ- cyclodextrins. Our intention is to highlight the most relevant publications on the synthesis of nanoparticle-cyclodextrin (NP-CD) nanohybrids, with CDs acting as reducing agents or through the post-synthetic modification of inorganic nanoparticles with CDs. We also discuss the new or enhanced properties that arise from the host-guest capabilities of the CDs and inorganic nanoparticles. Finally, we illustrate the potential applications of these materials in numerous research fields.

The thermal/pH-sensitive drug delivery system encapsulated by PAA based on hollow hybrid nanospheres with two silicon source

The synthesis of drug delivery systems based on hollow mesoporous silica nanoparticles (MSNs) is still a major challenge. In this work, the hollow hybrid MSNs were successfully prepared by cetyltrimethylammonium bromide-directed sol-gel process and one-step hydrothermal treatment process. The hollow hybrid MSNs had hybrid ethane-bridged frameworks with the uniform particle size (250 nm) and mesoporous pore diameter (3.7 nm). The polyacrylic acid (PAA) encapsulated drug delivery system based on hollow hybrid MSNs was prepared by using silanization, surface modification, doxorubicin hydrochloride (DOX) loading, and PAA coating. Drug encapsulation and release behavior at different temperatures and pH were studied by using DOX as a model guest molecule. The results displayed that the modified hollow ethane-bridged MSNs possessed good biocompatibility and excellent thermal/pH-dual-sensitive drug release property. This novel thermal/pH-sensitive drug delivery system based on hollow ethane-bridged MSNs has the advantages of feasible synthesis, no cytotoxicity, and good drug loading capacity, which may have potential applications in the anticancer therapy.

Mesoporous silica nanoparticles: synthesis methods and their therapeutic use-recent advances

Mesoporous silica nanoparticles (MSNPs) are a particular example of innovative nanomaterials for the development of drug delivery systems. MSNPs have recently received more attention for biological and pharmaceutical applications due to their capability to deliver therapeutic agents. Due to their unique structure, they can function as an effective carrier for the delivery of therapeutic agents to mitigate diseases progress, reduce inflammatory responses and consequently improve cancer treatment. The potency of MSNPs for the diagnosis and management of various diseases has been studied. This literature review will take an in-depth look into the properties of various types of MSNPs (e.g. shape, particle and pore size, surface area, pore volume and surface functionalisation), and discuss their characteristics, in terms of cellular uptake, drug delivery and release. MSNPs will then be discussed in terms of their therapeutic applications (passive and active tumour targeting, theranostics, biosensing and immunostimulative), biocompatibility and safety issues. Also, emerging trends and expected future advancements of this carrier will be provided.

Synthesis of Multiarm Peptide Dendrimers for Dual Targeted Thrombolysis

Current thrombolytic agents generally possess low specificity and pose a high risk of intracranial hemorrhage. Here, various generations of multiarm polylactic acid-polyglutamic acid peptide dendrimers were synthesized, and then nattokinase-combining magnetic Fe₃O₄ nanoparticles and RGD-modified dendrimers (Fe₃O₄-(4-PLA(G₃)₄)-RGD) were fabricated for targeted thrombi dissolution. Their in vitro and in vivo thrombolytic properties were determined. In vitro determination indicated that Fe₃O₄-(4-PLA(G₃)₄)-RGD/nattokinase provided 3-fold higher blood clot dissolution than that obtained with free nattokinase. An in vivo thrombolytic examination revealed that most of the thrombi were dissolved under an external magnetic field. In addition, there were many nanoparticles in vascular endothelial cells, demonstrating the RGD and magnetic dual targeting capacity of Fe₃O₄-(4-PLA(G₃)₄)-RGD/nattokinase. These results demonstrated that Fe₃O₄-(4-PLA(G₃)₄)-RGD nanoparticles not only will deliver targeted thrombolytic agents to enhance the efficacy of site-specific thrombolytic treatment but also have potential in the diagnosis of thrombotic disease in its early stages.

Principles of Magnetic Hyperthermia: A Focus on Using Multifunctional Hybrid Magnetic Nanoparticles

Hyperthermia is a noninvasive method that uses heat for cancer therapy where high temperatures have a damaging effect on tumor cells. However, large amounts of heat need to be delivered, which could have negative effects on healthy tissues. Thus, to minimize the negative side effects on healthy cells, a large amount of heat must be delivered only to the tumor cells. Magnetic hyperthermia (MH) uses magnetic nanoparticles particles (MNPs) that are exposed to alternating magnetic field (AMF) to generate heat in local regions (tissues or cells). This cancer therapy method has several advantages, such as (a) it is noninvasive, thus requiring surgery, and (b) it is local, and thus does not damage health cells. However, there are several issues that need to achieved: (a) the MNPs should be biocompatible, biodegradable, with good colloidal stability (b) the MNPs should be successfully delivered to the tumor cells, (c) the MNPs should be used with small amounts and thus MNPs with large heat generation capabilities are required, (d) the AMF used to heat the MNPs should meet safety conditions with limited frequency and amplitude ranges, (e) the changes of temperature should be traced at the cellular level with accurate and noninvasive techniques, (f) factors affecting heat transport from the MNPs to the cells must be understood, and (g) the effect of temperature on the biological mechanisms of cells should be clearly understood. Thus, in this multidisciplinary field, research is needed to investigate these issues. In this report, we shed some light on the principles of heat generation by MNPs in AMF, the limitations and challenges of MH, and the applications of MH using multifunctional hybrid MNPs.

Hybrid Magnetic Nanostructures For Cancer Diagnosis And Therapy

Cancer is the second disease in the world from the point of view of mortality. The conventional routes of treatment were found to be not sufficient and thus alternative ways are imposed. The use of hybrid, magnetic nanostructures is a promising way for simultaneous targeted diagnosis and treatment of various types of cancer. For this reason, the development of core@shell structures was found to be an efficient way to develop stable, biocompatible, non-toxic carriers with shell-dependent internalization capacity in cancer cells. So, the multicomponent approach can be the most suitable way to assure the multifunctionality of these nanostructures to achieve the desired/necessary properties. The in vivo stability is mostly assured by the coating of the magnetic core with various polymers (including polyethylene glycol, silica etc.), while the targeting capacity is mostly assured by the decoration of these nanostructures with folic acid. Unfortunately, there are also some limitations related to the multilayered approach. For instance, the increasing of the thickness of layers leads to a decrease the magnetic properties, (hyperthermia and guiding ability in the magnetic field, for instance), the outer shell should contain the targeting molecules (as well as the agents helping the internalization into the cancer cells), etc.

Cyclic iRGD peptide as a dual-functional on–off gatekeeper of mesoporous nanocontainers for targeting NRP-1 and selective drug release triggered by conformational conversion

A cyclic iRGD peptide as a dual-functional on–off gatekeeper on the surface of MSNs is prepared for specific NRP-1 targeting and selective drug release by conformational conversion.

Specific HER2 targeting and triggered drug release by conformational transformation of a dual-functional peptide gatekeeper on mesoporous nanocontainers

For specific targeting of HER2 and triggered drug release by stimuli-responsive conformational transformation, we developed a dual-functional cyclic peptide gatekeeper containing a HER2-binding sequence on the surface of mesoporous nanocontainers.

Approaches to improve the biocompatibility and systemic circulation of inorganic porous nanoparticles

The exploitation of various inorganic nanoparticles as drug carriers and therapeutics is becoming increasingly common. The first issue to be considered with regard to the nanomaterials being utilized in medicine centers on their safety. The functionality of nanocarriers in real-life environments explains the enthusiasm for their use. Several functionalities are typically added onto nanocarriers but the most crucial feature of those carriers intended to be administered intravenously is that they should possess a long residence time in blood circulation. The present review focusses on the mesoporous nanoparticles due to their great promise in nanomedicine and concentrates on their coatings because it is the outmost layer which dictates their first interactions with the surroundings and often determines their biofate.

Magnetic iron oxide nanoparticles as drug carriers: preparation, conjugation and delivery

Magnetic nanoparticles (MNPs), particularly made of iron oxides, have been extensively studied as diagnostic imaging agents and therapeutic delivery vehicles. In this review, special emphasis is set on the 'recent advancements of drug-conjugated MNPs used for therapeutic applications'. The most prevalent preparation methods and chemical functionalization strategies required for translational biomedical nanoformulations are outlined. Particular attention is, then, devoted to the tailored conjugation of drugs to the MNP carrier according to either noncovalent or covalent attachments, with advantages and drawbacks of both pathways conferred. Notable examples are presented to demonstrate the advantages of MNPs in respective drug-delivery applications. Understanding of the preparation, conjugation and delivery processes will definitely bring, in the next decades, a novel magneto-nanovehicle for effective theranostics.

Dual-functional cyclic peptide switch on mesoporous nanocontainers for selective CD44 targeting and on–off gatekeeping triggered by conformational transformation

A dual functional cyclic peptide gatekeeper with A6 sequence is designed not only for triggered drug release by conformational transformation of the peptide but also selective targeting of CD44.

Mesoporous Silica Nanocarriers with Cyclic Peptide Gatekeeper: Specific Targeting of Aminopeptidase N and Triggered Drug Release by Stimuli-Responsive Conformational Transformation

Utilizing stimuli-responsive conformational transformation of a cyclic peptide as a gatekeeper for mesoporous nanocarriers has several advantages such as facile introduction of targeting capabilities, low enzymatic degradation during blood circulation and enhanced specific binding to selected cells. In this report, a Asn-Gly-Arg (NGR)-containing dual-functional cyclic peptide gatekeeper on the surface of mesoporous nanocarrier is prepared not only for active targeting of the aminopeptidase N (APN) expressed on cancer cells but also stimuli-responsive intracellular drug release triggered by a glutathione (GSH)-induced conformational transformation of the peptide gatekeeper. The peptide gatekeeper on the surface of nanocarriers exhibits on-off gatekeeping by conformational transformation triggered by intracellular glutathione of the cancer cells. H1299 cells (high APN expression) showed greater uptake of the nanocarrier by endocytosis and higher apoptosis than A549 cells (low APN expression).

Mesoporous nanocarriers with a stimulus-responsive cyclodextrin gatekeeper for targeting tumor hypoxia

Tissue hypoxia developed in most malignant tumors makes a significant difference to normal tissues in the reduction potential and the activity of various bioreductive enzymes. Given the superior enzymatic activity of NAD(P)H:quinone oxidoreductase 1 (NQO1, a cytosolic reductase up-regulated in many human cancers) in hypoxia relative to that in normoxia, NQO1 has great potential for targeting hypoxic tumor cells. In the present report, the core concept of hypoxic NQO1-responsive mesoporous silica nanoparticles (MSNs) is based on the reasoning that the superior enzymatic activity of NQO1 within hypoxic cancer cells can be utilized as a key stimulus for the selective cleavage of an azobenzene stalk triggering the on-off gatekeeping for controlled release of guest drugs. We corroborate that the NQO1 specifically triggers to release the entrapped drug in the nanochannel of MSNs by reductive cleavage of the azobenzene linker only under hypoxic conditions in a controlled manner not only in vitro but also in vivo. Therefore, our results indicate that Si-Azo-CD-PEG could be utilized as a hypoxic cancer-targeting drug delivery carrier, and further suggest that the azobenzene linker could generally be useful for the construction of hypoxic NQO1-responsive nanomaterials.

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.

Stimuli-responsive α-helical peptide gatekeepers for mesoporous silica nanocarriers

A stimuli-responsive α-helical peptide, as a gatekeeper on the surface of mesoporous silica nanoparticles, efficiently controlled the release of entrapped drugs through triggered conformational conversion and effectively disrupted lipid membranes.

A mesoporous nanocontainer gated by a stimuli-responsive peptide for selective triggering of intracellular drug release

Mesoporous silica nanocontainers (MSNs) with biologically responsive gatekeepers have great potential for effective delivery of cargo molecules to the desired sites. For that purpose, peptides could be effective candidates as gatekeepers because of their bioresponsiveness and targeting capability. Taking advantage of the zinc finger domain peptide (CXXC), we designed a biocompatible all-peptide gatekeeper (WCGKC) with on-off gatekeeping capability through stimulus-responsive conformational conversion and the steric bulkiness of the tryptophan unit. The turn structure induced by an intramolecular disulfide bond of the peptide gatekeeper (WCGKC-SS) completely inhibited the release of the entrapped doxorubicin (DOX). However, upon reduction of the disulfide bond by glutathione (GSH), the peptide conformation was converted to a random structure, which opened the orifice of the mesopore leading to the release of DOX. The amine moiety of the lysine of the peptide gatekeeper was PEGylated to enhance dispersion stability and biocompatibility of the nanocontainer. Furthermore, the MSNs with the peptide gatekeeper (PEG-WCGKC-SS-Si) selectively released the entrapped DOX in A549 human lung cancer cells in a controlled manner triggered by intracellular GSH, but not in CCD normal lung cells containing a low intracellular GSH level. In A549 cells, DOX-loaded PEG-WCGKC-SS-Si exhibited about 10-times higher cytotoxicity induced by apoptosis than that in CCD cells.

Coupling the magnetic and heat dissipative properties of Fe3O4 particles to enable applications in catalysis, drug delivery, tissue destruction and remote biological interfacing

As interest in nanomaterials continues to grow, and the scope of their applications widens, one subset of materials has set itself apart: magnetic nanoparticles (MNPs).

Recent Advance on Mesoporous Silica Nanoparticles-Based Controlled Release System: Intelligent Switches Open up New Horizon

Mesoporous silica nanoparticle (MSN)-based intelligent transport systems have attracted many researchers' attention due to the characteristics of uniform pore and particle size distribution, good biocompatibility, high surface area, and versatile functionalization, which have led to their widespread application in diverse areas. In the past two decades, many kinds of smart controlled release systems were prepared with the development of brilliant nano-switches. This article reviews and discusses the advantages of MSN-based controlled release systems. Meanwhile, the switching mechanisms based on different types of stimulus response are systematically analyzed and summarized. Additionally, the application fields of these devices are further discussed. Obviously, the recent evolution of smart nano-switches promoted the upgrading of the controlled release system from the simple "separated" switch to the reversible, multifunctional, complicated logical switches and selective switches. Especially the free-blockage switches, which are based on hydrophobic/hydrophilic conversion, have been proposed and designed in the last two years. The prospects and directions of this research field are also briefly addressed, which could be better used to promote the further development of this field to meet the needs of mankind.

Voltage/pH-Driven Mechanized Silica Nanoparticles for the Multimodal Controlled Release of Drugs

The major challenges of current drug delivery systems for combination chemotherapy focus on how to efficiently transport drugs to target sites and release multiple drugs in a programmed manner. Herein, we report a novel multidrug delivery system, MSNPs 1, based on mechanized silica nanoparticles, which were constructed through functionalization of mesoporous silica nanoparticles with the acid-cleavable intermediate linkages and the monoferrocene functionalized β-cyclodextrin (Fc-β-CD) as supramolecular nanovalves. MSNPs 1 achieved zero premature release in the physiological pH solution and realized two different release modalities. In modality 1, MSNPs 1 released the encapsulated drugs gemcitabine (GEM) and doxorubicin (DOX) in sequence when they were successively applied to voltage and acid stimuli. The release time and dosage of GEM were precisely controlled via external voltage. The subsequent acid-triggered release of DOX was attributed to breakage of the intermediate linkages containing ketal groups. Modality 2 is the concurrent release of these two drugs directly upon acid exposure. Furthermore, the cell viability experiments demonstrated that MSNPs 1 had an improved cytotoxicity to MCF7 cells in comparison with single DOX- or GEM-loaded mechanized silica nanoparticles. We envisage that MSNPs 1 will play an important role in research and development for a new generation of controlled-release drug delivery system.

Core-shell-type magnetic mesoporous silica nanocomposites for bioimaging and therapeutic agent delivery

Advances in nanotechnology and nanomedicine offer great opportunities for the development of nanoscaled theranostic platforms. Among various multifunctional nanocarriers, magnetic mesoporous silica nanocomposites (M-MSNs) attract prominent research interest for their outstanding properties and potential biomedical applications. This Research News article highlights recent progress in the design of core-shell-type M-MSNs for both diagnostic and therapeutic applications. First, an overview of synthetic strategies for three representative core-shell-type M-MSNs with different morphologies and structures is presented. Then, the diagnostic functions of M-MSNs is illustrated for magnetic resonance imaging (MRI) applications. Next, magnetic targeted delivery and stimuli-responsive release of drugs, and effective package of DNA/siRNA inside mesopores using M-MSNs as therapeutic agent carriers are discussed. The article concludes with some important challenges that need to be overcome for further practical applications of M-MSNs in nanomedicine.

Acetalated-dextran as valves of mesoporous silica particles for pH responsive intracellular drug delivery

A pH-sensitive drug release system using acetalated-dextran as valves was designed to manipulate smart intracellular release of anticancer drugs.

Cytochrome c end-capped mesoporous silica nanoparticles as redox-responsive drug delivery vehicles for liver tumor-targeted triplex therapy in vitro and in vivo

To develop carriers for efficient anti-cancer drug delivery with reduced side effects, a biocompatible and redox-responsive nanocontainer based on mesoporous silica nanoparticles (MSNs) for tumor-targeted triplex therapy was reported in this study. The nanocontainer was fabricated by immobilizing cytochrome c (CytC) onto the MSNs as sealing agent via intermediate linkers of disulfide bonds for redox-responsive intracellular drug delivery. AS1411 aptamer was further tailored onto MSNs for cell/tumor targeting. The successful construction of redox- responsive MSNs was confirmed by BET/BJH analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy and thermogravimetric analysis (TGA), respectively. Detailed investigations demonstrated that anticancer drug of doxorubicin (DOX) loaded nanocontainer could be triggered by reductant (e.g. glutathione) within cellular microenvironment and release DOX to induce tumor cell apoptosis in vitro. More importantly, the nanocontainer displayed great potential for tumor targeting and achieved triplex therapy effects on the tumor inhibition in vivo through the loading DOX, gatekeeper of CytC and AS1411 aptamer, which were reflected by the change of tumor size, TUNEL staining and HE staining assays.

Colloidal particles containing labeling agents and cyclodextrins for theranostic applications

This review aims to give to the reader some new light on cyclodextrin (CD)-based theranostic agents in order to complete our recently published review dedicated to CD-particles conjugates in drug delivery systems (Zafar et al., 2014). CDs are biocompatible sugar-based macrocycles used in a wide range of biomedical applications. Here, we mainly focus on fundamental theranostic approaches combining the use of cyclodextrin molecules and colloidal particles as theranostic agents. The system's key features are discussed and a few recent pertinent applications are presented. CDs are used in order to enhance theranostic properties by providing apolar cavities for the encapsulation of hydrophobic moieties. Thus, CD molecules are used to enhance the loading capacity of particles by hosting active molecules. The relevance of CDs in enhancing the labeling properties of particles and the preparation of controlled drug release particles is also highlighted.

Cyclodextrin-based molecular machines

This chapter overviews molecular machines based on cyclodextrins (CDs). The categories of CD-based molecular machines, external stimuli for CD-based molecular machines, and typical examples of CD-based molecular machines are briefly described.

Poly(propylene imine) dendrimer caps on mesoporous silica nanoparticles for redox-responsive release: smaller is better

To elucidate the importance of the size of capping agents in stimulus-induced release systems from mesoporous silica nanoparticles (MSNs), the effectiveness of poly(propylene imine) dendrimers in controlling the model drug release was studied. MCM-41-type MSNs were synthesized and characterized. Fluorescent compounds (fluorescein disodium salt and carboxyfluorescein) were loaded in the porous structure of the MSNs and entrapped in the silica matrix with the dendrimers of generations I through V by anchoring dendrimers on the MSN surface through disulfide bonds. Stimulus-induced release of the cargo was studied in the presence of dithiothreitol (DTT). Dendrimers of generations I and II were found to be more effective in model drug retention and subsequent release than higher generations. Moreover, MSNs modified with larger amounts of dendrimers lowered the cargo release in the presence of DTT. These findings are of importance for optimizing drug delivery systems based on responsive MSNs as they enable tuning of the amount of the released cargo by choosing the capping agent of appropriate size.