Novel pH-responsive alginate-stabilized curcumin-selenium-ZIF-8 nanocomposites for synergistic breast cancer therapy

In this study, a novel selenium@zeolitic imidazolate framework core/shell nanocomposite stabilised with alginate was used to improve the anti-tumour activity of curcumin. The developed alginate-stabilised curcumin-loaded selenium@zeolitic imidazolate framework (Alg@Cur@Se@ZIF-8) had a mean diameter of 159.6 nm and polydispersity index < 0.25. The release of curcumin from the nanocarrier at pH 5.4 was 2.69 folds as high as at pH 7.4. The bare nanoparticles showed haemolytic activity of about 12.16% at a concentration of 500 µg/mL while covering their surface with alginate reduced this value to 5.2%. By investigating cell viability, it was found that Alg@Cur@Se@ZIF-8 caused more cell death than pure curcumin. Additionally, in vivo studies showed that Alg@Cur@Se@ZIF-8 dramatically reduced tumour growth compared to free curcumin in 4T1 tumour-bearing mice. More importantly, the histological study confirmed that the developed drug delivery system successfully inhibited lung and liver metastasis while causing negligible toxicity in vital organs. Overall, due to the excellent inhibitory activity on cancerous cell lines and tumour-bearing animals, Alg@Cur@Se@ZIF-8 can be considered promising for breast cancer therapy.

Nanobiotechnology-based strategies in alleviation of chemotherapy-mediated cardiotoxicity

The cardiovascular diseases have been among the most common malignancies and the first leading cause of death, even higher than cancer. The cardiovascular diseases can be developed as a result of cardiac dysfunction and damages to heart tissue. Exposure to toxic agents and chemicals that induce cardiac dysfunction has been of interest in recent years. The chemotherapy drugs are commonly used for cancer therapy and in these patients, cardiovascular diseases have been widely observed that is due to negative impact of chemotherapy drugs on the heart. These drugs increase oxidative damage and inflammation, and mediate apoptosis and cardiac dysfunction. Hence, nanotechnological approaches have been emerged as new strategies in attenuation of chemotherapy-mediated cardiotoxicity. The first advantage of nanoparticles can be explored in targeted and selective delivery of drugs to reduce their accumulation in heart tissue. Nanostructures can deliver bioactive and therapeutic compounds in reducing cardiotoxicity and alleviation toxic impacts of chemotherapy drugs. The functionalization of nanostructures increases their selectivity against tumor cells and reduces accumulation of drugs in heart tissue. The bioplatforms such as chitosan and alginate nanostructures can also deliver chemotherapy drugs and reduce their cardiotoxicity. The function of nanostructures is versatile in reduction of cardiotoxicity by chemotherapy drugs and new kind of platforms is hydrogels that can mediate sustained release of drug to reduce its toxic impacts on heart tissue. The various kinds of nanoplatforms have been developed for alleviation of cardiotoxicity and their future clinical application depends on their biocompatibility. High concentration level of chitosan nanoparticles can stimulate cardiotoxicity. Therefore, if nanotechnology is going to be deployed for drug delivery and reducing cardiotoxicity, the first pre-requirement is to lack toxicity on normal cells and have high biocompatibility.

Recent advances in cellulose, pectin, carrageenan and alginate-based oral drug delivery systems

Polymers-based drug delivery systems constitute one of the highly explored thrust areas in the field of the medicinal and pharmaceutical industries. In the past years, the properties of polymers have been modified in context to their solubility, release kinetics, targeted action site, absorption, and therapeutic efficacy. Despite the availability of diverse synthetic polymers for the bioavailability enhancement of drugs, the use of natural polymers is still highly recommended due to their easy availability, accessibility, and non-toxicity. The aim of the review is to provide the available literature of the last five years on oral drug delivery systems based on four natural polymers i.e., cellulose, pectin, carrageenan, and alginate in a concise and tabulated manner. In this review, most of the information is in tabulated form to provide easy accessibility to the reader. The data related to active pharmaceutical ingredients and supported components in different formulations of the mentioned polymers have been made available.

Activatable dual-functional molecular agents for imaging-guided cancer therapy

Theranostics has attracted great attention due to its ability to combine the real-time diagnosis of cancers with efficient treatment modalities. Activatable dual-functional molecular agents could be synthesized by covalently conjugating imaging agents, therapeutic agents, stimuli-responsive linkers and/or targeting molecules together. They could be selectively activated by overexpressed physiological stimuli or external triggers at the tumor sites to release imaging agents and cytotoxic drugs, thus offering many advantages for tumor imaging and therapy, such as a high signal-to-noise ratio, low systemic toxicity, and improved therapeutic effects. This review summarizes the recent advances of dual-functional molecular agents that respond to various physiological or external stimuli for cancer theranostics. The molecular designs, synthetic strategies, activatable mechanisms, and biomedical applications of these molecular agents are elaborated, followed by a brief discussion of the challenges and opportunities in this field.

Alginate-Derivative Encapsulated Carbon Coated Manganese-Ferrite Nanodots for Multimodal Medical Imaging

Carbon-decorated ferrite nanodots (MNF@Cs) have been enhanced with superparamagnetism and higher fluorescence quantum yield by encapsulation with an alginate derivative to create a cost-effective and less toxic multimodal contrast agent for replacing the conventional heavy metal Gd-containing contrast agent used in MR imaging. The novel surface-engineered particles (MNF@C-OSAs), devoid of labels, can simultaneously provide both longitudinal and transverse relaxation-based magnetic resonance imaging (MRI) and fluorescence emission. According to the findings of in vitro studies, the calculated molar relaxivities and the molar radiant efficiencies are indicative of the multimodal efficacy of MNF@C-OSA as compared with MNF@C particles and conventional contrast agents used in medical imaging. MNF@C-OSAs were shown to be significantly biocompatible and negligibly toxic when assessed against A549 cells and zebrafish embryos, indicating their potential for use as theranostic agents.

The role of imaging in targeted delivery of nanomedicine for cancer therapy

Nanomedicines overcome the pharmacokinetic limitations of traditional drug formulations and have promising prospect in cancer treatment. However, nanomedicine delivery in vivo is still facing challenges from the complex physiological environment. For the purpose of effective tumor therapy, they should be designed to guarantee the five features principle, including long blood circulation, efficient tumor accumulation, deep matrix penetration, enhanced cell internalization and accurate drug release. To ensure the excellent performance of the designed nanomedicine, it would be better to monitor the drug delivery process as well as the therapeutic effects by real-time imaging. In this review, we summarize strategies in developing nanomedicines for efficiently meeting the five features of drug delivery, and the role of several imaging modalities (fluorescent imaging (FL), magnetic resonance imaging (MRI), computed tomography (CT), photoacoustic imaging (PAI), positron emission tomography (PET), and electron microscopy) in tracing drug delivery and therapeutic effect in vivo based on five features principle.

A Biodegradable Iridium(III) Coordination Polymer for Enhanced Two-Photon Photodynamic Therapy Using an Apoptosis-Ferroptosis Hybrid Pathway

The clinical application of photodynamic therapy is hindered by the high glutathione concentration, poor cancer-targeting properties, poor drug loading into delivery systems, and an inefficient activation of the cell death machinery in cancer cells. To overcome these limitations, herein, the formulation of a promising Ir^III complex into a biodegradable coordination polymer (IrS NPs) is presented. The nanoparticles were found to remain stable under physiological conditions but deplete glutathione and disintegrate into the monomeric metal complexes in the tumor microenvironment, causing an enhanced therapeutic effect. The nanoparticles were found to selectively accumulate in the mitochondria where these trigger cell death by hybrid apoptosis and ferroptosis pathways through the photoinduced production of singlet oxygen and superoxide anion radicals. This study presents the first example of a coordination polymer that can efficiently cause cancer cell death by apoptosis and ferroptosis upon irradiation, providing an innovative approach for cancer therapy.

Targeted delivery and enhanced uptake of chemo-photodynamic nanomedicine for melanoma treatment

Nanoparticles (NPs) modified with targeting ligands have often shown great potential in targeted drug delivery for tumor therapy. However, the clearance of NPs by the monocyte-phagocyte system (MPS) and the relatively low cellular uptake by tumor cells have significantly limited the antitumor efficacy of a variety of nanomedicines. Tumor microenvironment-mediated multidrug resistance also reduces the antitumor efficacy of internalized nanomedicines. Herein, we developed an innovative nanomedicine for combined chemo-photodynamic therapy of melanoma through targeted drug delivery and significantly improved the cellular uptake of the nanomedicine through the charge-reversal phenomenon. An amphiphilic platinum (IV)-polyethylenimine-chlorin e6 (Pt(IV)-PEI-Ce6) polymer was designed, prepared, and self-assembled into NPs (PPC) in an aqueous solution, and these NPs were subsequently coated with hyaluronic acid (HA) to afford PPC@HA. The surface-coated HA provided PPC with a negatively charged surface potential to reduce the clearance by the MPS during systemic circulation and enhanced the targeted delivery of PPC to CD44-overexpressing melanoma cells. Upon accumulation in the tumor site, hyaluronidase overexpressed in the tumor induced HA degradation to release the positively charged PPC, resulting in an increased internalization of PPC into tumor cells. Bioactive Pt(II) was released in response to high glutathione level in the tumor cells for effective tumor chemotherapy. Under 650 nm laser irradiation, Ce6 produced reactive oxygen species (ROS), thus driving photodynamic therapy. Finally, PPC@HA exhibited combined photodynamic-chemotherapeutic antitumor efficacy against the melanoma cells in mice. STATEMENT OF SIGNIFICANCE: Tumors are one of the greatest threats to human health, and chemotherapy has been one of the most common therapeutic modalities for treating tumors; however, many challenges related to chemotherapy remain, such as low delivery efficiency, side effects, and unsatisfactory therapeutic efficacy. Nanomedicines modified with targeting ligands have often shown great potential in improving targeted drug delivery for tumor therapy; however, the clearance of nanomaterials by the monocyte-phagocyte system and the relatively low cellular uptake by tumor cells have significantly limited the antitumor efficacy of a variety of nanomedicines. Herein, we developed a novel charge-reversal-based, hyaluronic acid-coated, Pt(IV) prodrug and chlorin e6-based nanomedicine to improve systemic circulation and targeted accumulation of the nanomedicine in the tumor tissue and to enhance its intracellular uptake. This nanomedicine may provide a potential new platform to improve the drug content inside tumor cells and to effectively inhibit tumor growth through combined chemotherapy and photodynamic therapy.

Intranasal Administration of Catechol-Based Pt(IV) Coordination Polymer Nanoparticles for Glioblastoma Therapy

Cisplatin has been described as a potent anticancer agent for decades. However, in the case of glioblastomas, it is only considered a rescue treatment applied after the failure of second-line treatments. Herein, based on the versatility offered by coordination chemistry, we engineered nanoparticles by reaction of a platinum (IV) prodrug and iron metal ions showing in vitro dual pH- and redox-sensitivity, controlled release and comparable cytotoxicity to cisplatin against HeLa and GL261 cells. In vivo intranasal administration in orthotopic preclinical GL261 glioblastoma tumor-bearing mice demonstrated increased accumulation of platinum in tumors, leading in some cases to complete cure and prolonged survival of the tested cohort. This was corroborated by a magnetic resonance imaging follow-up, thus opening new opportunities for intranasal glioblastoma therapies while minimizing side effects. The findings derived from this research showed the potentiality of this approach as a novel therapy for glioblastoma treatment.

Biodegradable Polymer with Effective Near-Infrared-II Absorption as a Photothermal Agent for Deep Tumor Therapy

Photothermal therapy holds great promise for cancer treatment due to its effective tumor ablation and minimal invasiveness. Herein a new class of biodegradable photothermal agents with effective adsorption in both near-infrared-I (NIR-I) and NIR-II windows is reported for deep tumor therapy. As demonstrated in a deep-seated ovarian cancer model, photothermal therapy using 1064 nm irradiation effectively inhibits tumor progression and prolongs survival spans. This work provides a new design of photothermal agents toward a more effective therapy of tumors.

Thiolated Nanoparticles for Biomedical Applications: Mimicking the Workhorses of Our Body

Advances in nanotechnology have generated a broad range of nanoparticles (NPs) for numerous biomedical applications. Among the various properties of NPs are functionalities being related to thiol substructures. Numerous biological processes that are mediated by cysteine or cystine subunits of proteins representing the workhorses of the bodies can be transferred to NPs. This review focuses on the interface between thiol chemistry and NPs. Pros and cons of different techniques for thiolation of NPs are discussed. Furthermore, the various functionalities gained by thiolation are highlighted. These include overall bio- and mucoadhesive, cellular uptake enhancing, and permeation enhancing properties. Drugs being either covalently attached to thiolated NPs via disulfide bonds or being entrapped in thiolated polymeric NPs that are stabilized via inter- and intrachain crosslinking can be released at the diseased tissue or in target cells under reducing conditions. Moreover, drugs, targeting ligands, biological analytes, and enzymes bearing thiol substructures can be immobilized on noble metal NPs and quantum dots for therapeutic, theranostic, diagnostic, biosensing, and analytical reasons. Within this review a concise summary and analysis of the current knowledge, future directions, and potential clinical use of thiolated NPs are provided.

Dynamic nano-assemblies based on two-dimensional inorganic nanoparticles: Construction and preclinical demonstration

Dynamic drug delivery systems (DDSs) have the ability of transforming their morphology and functionality in response to the biological microenvironments at the disease site and/or external stimuli, show spatio-temporally controllable drug delivery, and enhance the treatment efficacy. Due to the large surface area and modification flexibility, two-dimensional (2D) inorganic nanomaterials are being increasingly exploited for developing intelligent DDSs for biomedical applications. In this review, we summarize the engineering methodologies used to construct transformable 2D DDSs, including changing compositions, creating defects, and surface dot-coating with polymers, biomolecules, or nanodots. Then we present and discuss dynamic inorganic 2D DDSs whose transformation is driven by the diseased characteristics, such as pH gradient, redox, hypoxia, and enzyme in the tumor microenvironment as well as the external stimuli including light, magnetism, and ultrasound. Finally, the limitations and challenges of current transformable inorganic DDSs for clinical translation and their in vivo safety assessment are discussed.

Nano-assembly of ruthenium(II) photosensitizers for endogenous glutathione depletion and enhanced two-photon photodynamic therapy

Photodynamic therapy (PDT) is a promising noninvasive cancer treatment. PDT in the clinic faces several hurdles due to the unique tumor environment, a feature of which is high levels of glutathione (GSH). An excess amount of GSH consumes reactive oxygen species (ROS) generated by photosensitizers (PSs), reducing PDT efficiency. Herein, nano-photosensitizers (RuS1 NPs and RuS2 NPs) are reported. These consist of ruthenium complexes joined by disulfide bonds forming GSH sensitive polymer nanoparticles. The NPs achieve enhanced uptake compared to their constituent monomers. Inside cancer cells, high levels of GSH break the S-S bonds releasing PS molecules in the cell. The level of GSH is also then reduced leading to excellent PDT activity. Furthermore, RuS2 NPs functionalized with tumor targeting hyaluronic acid (HA@RuS2 NPs) assessed in vivo were highly effective with minimal side effects. To the best of our knowledge, RuS NPs are the first metal complex-based nano-assembled photosensitizers which exhibit enhanced specificity and consume endogenous GSH simultaneously, thus achieving excellent two-photon PDT efficiency in vitro and in vivo.

Wheat Germ Agglutinin-Conjugated Disulfide Cross-Linked Alginate Nanoparticles as a Docetaxel Carrier for Colon Cancer Therapy

PURPOSE

In chemotherapy, oral administration of drug is limited due to lack of drug specificity for localized colon cancer cells. The inability of drugs to differentiate cancer cells from normal cells induces side effects. Colonic targeting with polymeric nanoparticulate drug delivery offers high potential strategies for delivering hydrophobic drugs and fewer side effects to the target site. Disulfide cross-linked polymers have recently acquired high significance due to their potential to degrade in reducing colon conditions while resisting the upper gastrointestinal tract's hostile environment. The goal of this project is, therefore, to develop pH-sensitive and redox-responsive fluorescein-labeled wheat germ agglutinin (fWGA)-mounted disulfide cross-linked alginate nanoparticles (fDTP2) directly targeting docetaxel (DTX) in colon cancer cells.

METHODS

fDTP2 was prepared by mounting fWGA on DTX-loaded nanoparticles (DTP2) using the two-step carbodiimide method. Morphology of fDTP2 was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Dynamic light scattering (DLS) study was carried out to determine the mean diameter, polydispersity index (PDI) and zeta potential of fDTP2. Cellular uptake efficiency was examined using fluorescence microplate reader. Biocompatibility and active internalization of fDTP2 were conducted on HT-29.

RESULTS

fDTP2 was found to exhibit a DTX loading efficiency of 19.3%. SEM and TEM tests revealed spherical nanoparticles. The in vitro DTX release test showed a cumulative release of 54.7%. From the DLS study, fDTP2 reported a 277.7 nm mean diameter with PDI below 0.35 and -1.0 mV zeta potential. HT-29 which was fDTP2-treated demonstrated lower viability than L929 with a half maximal inhibitory concentration (IC50) of 34.7 µg/mL. HT-29 (33.4%) internalized fDTP2 efficiently at 2 h incubation. The study on HT-29 active internalization of nanoparticles through fluorescence and confocal imaging indicated such.

CONCLUSION

In short, fDTP2 demonstrated promise as a colonic drug delivery DTX transporter.

Harnessing Endogenous Stimuli for Responsive Materials in Theranostics

Materials that respond to endogenous stimuli are being leveraged to enhance spatiotemporal control in a range of biomedical applications from drug delivery to diagnostic tools. The design of materials that undergo morphological or chemical changes in response to specific biological cues or pathologies will be an important area of research for improving efficacies of existing therapies and imaging agents, while also being promising for developing personalized theranostic systems. Internal stimuli-responsive systems can be engineered across length scales from nanometers to macroscopic and can respond to endogenous signals such as enzymes, pH, glucose, ATP, hypoxia, redox signals, and nucleic acids by incorporating synthetic bio-inspired moieties or natural building blocks. This Review will summarize response mechanisms and fabrication strategies used in internal stimuli-responsive materials with a focus on drug delivery and imaging for a broad range of pathologies, including cancer, diabetes, vascular disorders, inflammation, and microbial infections. We will also discuss observed challenges, future research directions, and clinical translation aspects of these responsive materials.

A comprehensive review on alginate-based delivery systems for the delivery of chemotherapeutic agent: Doxorubicin

Doxorubicin (DOX), an anthracycline drug, is widely used for the treatment of several cancers like osteosarcoma, cervical carcinoma, breast cancer, etc. DOX lacks target specificity; thereby it also affects normal cells thus resulting in several side-effects. A drug delivery system (DDS) can be used to deliver the drug in a controlled and sustained manner at a targeted site within the body. Various DDS like nanoemulsions, polymeric nanoparticles, and liposomes are used for loading DOX. Alginate, a polysaccharide is widely used for fabricating DDS due to its biodegradable and bio-compatible properties. Alginates, in combination with other biomaterials, have been extensively used as a novel drug delivery carrier for DOX. Alginate provides a platform for drug delivery in different forms like hydrogels, nanogels, nanoparticles, microparticles, graphene oxide systems, magnetic systems, etc. Herein, we briefly describe alginate in combination with other materials as a nanocarrier for targeted delivery of DOX for anti-cancer treatment.

Preparation, characterization, and in vitro drug release behavior of thiolated alginate nanoparticles loaded budesonide as a potential drug delivery system toward inflammatory bowel diseases

For site-specific drug delivery in inflammatory bowel disease, reducible sodium alginate nanoparticles cross-linked with disulfide linkage were developed. Nanoparticles were synthesized in deionized water through self-assembly of amphiphilic thiolated sodium alginate Alg-Cys and subsequently produced cross-linking of disulfide bonds. TEM image showed a spherical core-shell configuration with a size of about 430 nm for the nanoparticles. Dynamic light scattering (DLS) showed high stability, narrow size distribution, and pH-dependent swelling transition for the nanoparticles. Cytotoxicity study showed that there was no evident cell inhibition among the nanoparticles. Also, the size of the nanoparticles increased in 10 mM glutathione (GSH) solution due to the cleavage of disulfides within their network structures. Compared to that in GSH-free buffer, there was a remarkable increase in drug release in pH 7.4 buffer with GSH from drug-loaded nanoparticles, indicating that the nanoparticles could be used for colon-specific drug delivery.

Natural Ingredient-Based Polymeric Nanoparticles for Cancer Treatment

Cancer is a global health challenge. There are drawbacks to conventional chemotherapy such as poor bioavailability, development of drug resistance and severe side effects. Novel drug delivery system may be an alternative to optimize therapeutic effects. When such systems consist of natural materials, they offer important advantages: they are usually highly biocompatible, biodegradable, nontoxic and nonimmunogenic. Furthermore, natural materials can be easily modified for conjugation with a wide range of therapeutic agents and targeting ligands, according to the therapeutic purpose. This article reviews different natural ingredients and their applications in drug delivery systems for cancer therapy. Firstly, an overview of the polysaccharides and protein-based polymers that have been extensively investigated for drug delivery are described. Secondly, recent advances in using various natural ingredient-based polymeric nanoparticles for cancer therapy are reviewed. The characteristics of these delivery systems are summarized, followed by a discussion of future development and clinical potential. This review aims to summarize current knowledge and provide a basis for developing effective tailor-made formulations for cancer therapy in the future.

Formulation, Characterization and Biological Activity Screening of Sodium Alginate-Gum Arabic Nanoparticles Loaded with Curcumin

The approach of drug delivery systems emphasizes the use of nanoparticles as a vehicle, offering the optional property of delivering drugs as a single dose rather than in multiple doses. The current study aims to improve antioxidant and drug release properties of curcumin loaded gum Arabic-sodium alginate nanoparticles (Cur/ALG-GANPs). The Cur/ALG-GANPs were prepared using the ionotropic gelation technique and further subjected to physico-chemical characterization using attenuated total reflectance–Fourier transform infrared (ATR-FTIR), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), size distribution, and transmission electron microscopy (TEM). The size of Cur/ALG-GANPs ranged between 10 ± 0.3 nm and 190 ± 0.1 nm and the zeta potential was –15 ± 0.2 mV. The antioxidant study of Cur/ALG-GANPs exhibited effective radical scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) at concentrations that ranged between 30 and 500µg/mL. Cytotoxicity was performed using MTT assay to measure their potential in inhibiting the cell growth and the result demonstrated a significant anticancer activity of Cur/ALG-GANPs against human liver cancer cells (HepG2) than in colon cancer (HT29), lung cancer (A549) and breast cancer (MCF7) cells. Thus, this study indicates that Cur/ALG-GANPs have promising anticancer properties that might aid in future cancer therapy.

Redox-Responsive Dipeptide Nanostructures toward Targeted Cancer Therapy

Materials that exhibit responsiveness toward biological signals are currently subjected to intense research in the field of drug delivery. In our study, we tried to develop cancer-targeted and redox-responsive nanoparticles (NPs) from disulfide-linked oxidized cysteine-phenylalanine (CFO). The NPs were conjugated with folic acid (FA) to specifically target cancer cells, and the presence of disulfide bonds would enabled the disintegration of the particles in the presence of elevated levels of glutathione (GSH) in cancer cells. Anticancer drug doxorubicin (Dox) was successfully loaded inside the disulfide-linked nanoparticles (CFO-Dox-NPs), which further demonstrated stimuli-responsive drug release in the presence of GSH. We have also demonstrated enhanced uptake of FA-derivatized NPs (FA-CFO-NPs) in cancerous cells (C6 glioma and B16F10 melanoma cells) than in normal cells (HEK293T cells) due to the overexpression of FA receptors on the surface of cancer cells. Cytotoxicity studies in C6 cells and B16F10 cells further revealed enhanced efficacy of Dox loaded (FA-CFO-Dox-NPs) as compared to the native drug. The findings of this study clearly demonstrated that the disulfide-linked nanoparticle system may provide a promising selective drug delivery platform in cancer cells.

Synthesis of Temperature/pH Dual-Stimuli-Response Multicompartmental Microcapsules via Pickering Emulsion for Preprogrammable Payload Release

Stimuli-responsive microcapsules, which can release the encapsulated payload under various environmental stimuli, have attracted great interests of the food, pharmaceutical, cosmetics, and agricultural fields in recent years. However, most reported responsive microcapsules normally have a single storage area and thus load/release only one type of payload under one stimulus. In this work, we fabricated a novel kind of multicompartmental intelligent microcapsule with two storage areas and independently controlled (preprogrammable) releasing behavior under different stimuli via rapid photopolymerization of Pickering emulsions. In our strategy, a temperature-sensitive polymeric (N-isopropyl acrylamide, pNIPAM) particle was prepared and loaded with Nile Red (NR), which was then employed as a Pickering emulsifier to stabilize oil-in-water droplets. The oil was composed of pH-responsive monomers and oil-soluble fluorescent green (OG). Upon exposure to photoirradiation, pH-responsive monomers were polymerized along the interior of the droplets and converted into microcapsules. With NR in the temperature-sensitive pNIPAM@NR particles and OG in the interior of the microcapsules, the as-prepared microcapsules possess dual-carrier capability with two payloads encapsulated dependently in two different compartments. In addition, the microcapsules could respond to two different external stimuli (temperature and pH) and realize the selective and independent release of encapsulated molecules (NR and OG) from the shell and core without any mutual interference. More importantly, the release of NR and OG can be programmed by preprogramming the order of the stimulus responses, which can be altered. Our work develops a simple and effective strategy to fabricate responsive multicompartment microcapsules with preprogrammable release of different molecules.

Docetaxel-Loaded Disulfide Cross-Linked Nanoparticles Derived from Thiolated Sodium Alginate for Colon Cancer Drug Delivery

In this study, fluorescein-labelled wheat germ agglutinin (fWGA)-conjugated disulfide cross-linked sodium alginate nanoparticles were developed to specifically target docetaxel (DTX) to colon cancer cells. Different amounts of 3-mercaptopropionic acid (MPA) were covalently attached to sodium alginate to form thiolated sodium alginate (MPA1-5). These polymers were then self-assembled and air-oxidised to form disulfide cross-linked nanoparticles (MP1-5) under sonication. DTX was successfully loaded into the resulting MP1-5 to form DTX-loaded nanoparticles (DMP1-5). DMP2 had the highest loading efficiency (17.8%), thus was chosen for fWGA surface conjugation to form fWGA-conjugated nanoparticles (fDMP2) with a conjugation efficiency of 14.1%. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses showed spherical nanoparticles, and an in vitro drug release study recorded a cumulative drug release of 48.6%. Dynamic light scattering (DLS) analysis revealed a mean diameter (MD) of 289 nm with a polydispersity index (PDI) of 0.3 and a zeta potential of -2.2 mV for fDMP2. HT-29 human colon cancer cells treated with fDMP2 showed lower viability than that of L929 mouse fibroblast cells. These results indicate that fDMP2 was efficiently taken up by HT-29 cells (29.9%). Fluorescence and confocal imaging analyses also showed possible internalisation of nanoparticles by HT-29 cells. In conclusion, fDMP2 shows promise as a DTX carrier for colon cancer drug delivery.

Glutathione-adaptive peptide amphiphile vesicles rationally designed using positionable disulfide-bridges for effective drug transport

The drug loading/releasing capability of GSH-responsive nanovesicles self-assembled from peptide amphiphiles was controlled by varying the location and number of disulfide-linkages in the peptide for the selective drug-release into tumor cells.

Polymeric nanoparticles as carrier for targeted and controlled delivery of anticancer agents

In recent decades, many novel methods by using nanoparticles (NPs) have been investigated for diagnosis, drug delivery and treatment of cancer. Accordingly, the potential of NPs as carriers is very significant for the delivery of anticancer drugs, because cancer treatment with NPs has led to the improvement of some of the drug delivery limitations such as low blood circulation time and bioavailability, lack of water solubility, drug adverse effect. In addition, the NPs protect drugs against enzymatic degradation and can lead to the targeted and/or controlled release of the drug. The present review focuses on the potential of NPs that can help the targeted and/or controlled delivery of anticancer agents for cancer therapy.

Biocompatible disulphide cross-linked sodium alginate derivative nanoparticles for oral colon-targeted drug delivery

The application of layer-by-layer (LbL) approach on nanoparticle surface coating improves the colon-specific drug delivery of insoluble drugs. Here, we aimed to formulate a self-assembled cysteamine-based disulphide cross-linked sodium alginate with LbL self-assembly to improve the delivery of paclitaxel (PCX) to colonic cancer cells. Cysteamine was conjugated to the backbone of oxidized SA to form a core of self-assembled disulphide cross-linked nanospheres. P3DL was selected for PCX loading and fabricated LbL with poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSCMA) resulting from characterization and drug release studies. P3DL-fabricated PCX-loaded nanospheres (P3DL/PAH/PSSCMA) exhibited an encapsulation efficiency of 77.1% with cumulative drug release of 45.1%. Dynamic light scattering analysis was reported at 173.6 ± 2.5 nm with polydispersity index of 0.394 ± 0.105 (zeta potential= -58.5 mV). P3DL/PAH/PSSCMA demonstrated a pH-dependent swelling transition; from pH 1 to 7 (102.2% increase). The size increased by 33.0% in reduction response study after incubating with 10 mM glutathione (day 7). HT-29 cells showed high viabilities (86.7%) after treatment with the fabricated nanospheres at 0.8 µg/mL. Cellular internalization was successful with more than 70.0% nanospheres detected in HT-29 cells. Therefore, this fabricated nanospheres may be considered as potential nanocarriers for colon cancer-targeted chemotherapeutic drug delivery.

Stepwise dual stimuli triggered dual drug release by a single naphthalene based two-photon chromophore to reverse MDR for alkylating agents with dual surveillance in uncaging steps

A single chromophore based dinitrophenylsulphonyl–naphthalene–chlorambucil conjugate drug delivery system is presented for the dual stimuli controlled release of SO₂and chlorambucil.

Functionalized glycolipids for potential bioconjugation of vesicles

Two azide-terminated oligoethylene oxide spacered glycolipids have been synthesized, and their assembly behavior has been studied in comparison to the corresponding base surfactants. The results suggest potential of the Guerbet lactoside-based compound for targeted drug delivery, while a coiling of the ethylene oxide linker disfavors the application of the glucoside.

Cerasomes and Bicelles: Hybrid Bilayered Nanostructures With Silica-Like Surface in Cancer Theranostics

Over years, theranostic nanoplatforms have provided a new avenue for the diagnosis and treatment of various cancer types. To this end, a myriad of nanocarriers such as polymeric micelles, liposomes, and inorganic nanoparticles (NPs) with distinct physiochemical and biological properties are routinely investigated for preclinical and clinical studies. So far, liposomes have received great attention for various biomedical applications, however, it still suffers from insufficient morphological stability. On the other hand, inorganic NPs depicting excellent therapeutic ability have failed to address biocompatibility issues. This has raised a serious concern about the clinical approval of multifunctional organic or inorganic-based theranostic agents. Recently, partially silica coated nanohybrids such as cerasomes and bicelles demonstrating both diagnostic and therapeutic ability in a single system, have drawn profound attention as a fascinating novel drug delivery system. Compared with traditional liposomal or inorganic-based nanoformulations, this new and highly stable nanocarriers integrates the functional attributes of biomimetic liposomes and silica NPs, therefore, synergize strengths and functions, or even surpass weaknesses of individual components. This review at its best enlightens the emerging concept of such partially silica coated nanohybrids, fabrication strategies, and theranostic opportunities to combat cancer and related diseases.

Glutathione-responsive homodithiacalix[4]arene-based nanoparticles for selective intracellular drug delivery

Glutathione-responsive, paclitaxel-loaded nanoparticles based on homodithiacalix[4]arene were successfully developed, exhibiting selective drug release in cancer cells.

pH and reduction-activated polymeric prodrug nanoparticles based on a 6-thioguanine-dialdehyde sodium alginate conjugate for enhanced intracellular drug release in leukemia

Synthesis schematics of DSA and 6-TG-DSA as well as processes of PPN self-assembly and its pH/GSH dual stimuli-response release of the conjugated 6-TG.

Polyelectrolyte capsules preloaded with interconnected alginate matrix: An effective capsule system for encapsulation and release of macromolecules

In recent years, the design of stimuli-responsive hollow polymeric capsules is of tremendous interest for the scientific community because of the broad application of these capsules in the biomedical field. The use of weak polyelectrolytes as layer components for capsule fabrication is especially interesting as it results in hollow capsules that show unique release characteristics under physiological conditions. In this work, a methodology to prepare sub-micron sized alginate doped calcium carbonate (CaCO₃) particles through controlled precipitation in the presence of alginate is reported. Hollow capsules obtained by Layer-by-Layer (LbL) assembly of poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) (PMA) are showing an interconnected alginate matrix in the interior of the capsules. Investigations showed that the presence of alginate matrix enhances the encapsulation of cationic molecules (e.g. doxorubicin hydrochloride) manifold by charge controlled attraction mechanism. Capsule permeability investigated by confocal laser scanning microscopy revealed that the transformation from an open state to closed state is accompanied by an intermediate state where capsules are neither open nor closed. Furthermore, time dependent study indicated that the encapsulation process is linear as a function of time. The cell viability experiments demonstrated excellent biocompatibility of hollow capsules with mouse embryonic fibroblast cells. Anticancer investigations showed that DOX loaded capsules have significant anti-proliferative characteristics against HeLa cells. Such capsules have high potential for use as drug carrier for cationic drugs in cancer therapy.

pH-Responsive prodrug nanoparticles based on a sodium alginate derivative for selective co-release of doxorubicin and curcumin into tumor cells

In order to realize a combination of chemotherapy and selective drug release into tumor cells, novel pH-sensitive prodrugnanoparticles were designed and prepared via the self-assembly of a synthetic amphiphilic macromolecular prodrug for the selective co-delivery of doxorubicin (Dox) and curcumin (Cur). Dox was covalently conjugated to the oxidized sodium alginate through a Schiff base reaction to produce an amphiphilic macromolecular prodrug, and the prodrug was subsequently self-assembled into nanoparticles (Dox-NPs) in an aqueous solution, which were responsive to the acidic environment in tumor cells. Additionally, a second chemotherapeutic agent, Cur, was encapsulated in the core of nanoparticles (Cur-Dox-NPs) via hydrophobic effects, with a significant drug loading capacity. Cur-Dox-NPs exhibited an efficient release of both Dox and Cur in acidic media and further studies of their intracellular uptake and drug release confirmed that Dox-NPs were easily taken up by cells and selectively released the drug into the human breast cancer cell line MCF-7. In vitro cytotoxicity studies of the NPs showed a remarkable efficacy against MCF-7 cell lines, whereas an improved safety profile was observed in the human breast epithelial cell line MCF-10A. Furthermore, in vivo studies in zebrafish further confirmed an efficient absorption of Dox-NPs. In vivo cardiotoxicity experiments on a zebrafish model showed that Dox-NPs exhibited an improved cardiotoxicity profile in comparison with free Dox. This study demonstrated that this novel pH-sensitive prodrug-nanoparticle system may provide a simple and efficient platform for the selective co-delivery of multiple drugs to tumor cells.