Magnetic nanogels as dual triggered anticancer drug delivery: Toxicity evaluation on isolated rat liver mitochondria

Recent advances in nano-based drug delivery systems for treatment of liver cancer

Liver cancer is one of the aggressive primary tumors as evident by high rate of incidence and mortality. Conventional treatments (e.g. chemotherapy) suffer from various drawbacks including wide drug distribution, low localized drug concentration, and severe off-site toxicity. Therefore, they cannot satisfy the mounting need for safe and efficient cancer therapeutics, and alternative novel strategies are needed. Nano-based drug delivery systems (NDDSs) are among these novel approaches that can improve the overall therapeutic outcomes. NDDSs are designed to encapsulate drug molecules and target them specifically to liver cancer. Thus, NDDSs can selectively deliver therapeutic agents to the tumor cells and avoid distribution to off-target sites which should improve the safety profile of the active agents. Nonetheless, NDDSs should be well designed, in terms of the preparing materials, nanocarriers structure, and the targeting strategy, in order to accomplish these objectives. This review discusses the latest advances of NDDSs for cancer therapy with emphasis on the aforementioned essential design components. The review also entails the challenges associated with the clinical translation of NDDSs, and the future perspectives towards next-generation NDDSs.

Targeted delivery of quercetin using gelatin/starch/Fe3O4 nanocarrier to suppress the growth of liver cancer HepG2 cells

To suppress HepG2 liver cancer cells, a nanocarrier (NC) consisting of Fe3O4, Gelatin (G), and Starch (S) was synthesized and characterized for targeted delivery of Quercetin (QC) drug. The spectra obtained from X-ray diffraction (XRD) and Fourier transform infrared (FTIR) demonstrated that the nanoparticles (NP) in the NC are well-interconnected to each other and have formed a regular structure. Also, field emission scanning electron microscopy (FE-SEM) indicates a smooth and homogeneous surface of the synthesized NC. The results of the vibrating sample magnetometer (VSM) also corroborated the correctness of the synthesis of Fe3O4 NPs and Gelatin/Starch/Fe3O4@Quercetin NC (G/S/Fe3O4@QC) because the magnetic properties of Fe3O4 decreased with the addition of G/S@QC. Stability and particle size were determined by zeta potential and Dynamic light scattering (DLS). The percentage of drug loading and encapsulation efficiency of QC in the NC was 46.25 % and 87 %, respectively. QC profile release in acidic and natural environments showed controlled release and pH sensitivity of the NC. Cytotoxicity of L929 and HepG2 treated cells with the G/S/Fe3O4@QC was investigated by MTT staining, which agreed with the flow cytometry result. The results of Flowcytometry and MTT showed 43.5 % apoptosis and 42 % cytotoxicity in treated HepG2 cells by G/S/Fe3O4@QC, while it was not toxic to L929 normal cells. According to the results, G/S/Fe3O4@QC is a suitable NC for the targeted delivery of QC as a drug against HepG2 cancer cells.

Biopolymeric Nanogel as a Drug Delivery System for Doxorubicin-Improved Drug Stability and Enhanced Antineoplastic Activity in Skin Cancer Cells

In this study, doxorubicin was loaded in a chitosan-albumin nanogel with the aim of improving its stability and exploring the potential of the system in the treatment of skin cancer. Infrared spectroscopy and X-ray diffraction confirmed the encapsulation of the drug. Transmission electron microscopy revealed the spherical shape of the nanogel particles. The drug-loaded nanogel was characterized with a small diameter of 29 nm, narrow polydispersity (0.223) and positive zeta potential (+34 mV). The exposure of encapsulated doxorubicin to light (including UV irradiation and daylight) did not provoke any degradation, whereas the nonencapsulated drug was significantly degraded. In vitro studies on keratinocytes (HaCaT) and epidermoid squamous skin carcinoma cells (A-431) disclosed that the encapsulated doxorubicin was more cytotoxic on both cell lines than the pure drug was. More importantly, the cytotoxic concentration of encapsulated doxorubicin in carcinoma cells was approximately two times lower than that in keratinocytes, indicating that it would not affect them. Thus, the loading of doxorubicin into the developed chitosan-albumin nanogel definitely stabilized the drug against photodegradation and increased its antineoplastic effect on the skin cancer cell line.

Herceptin-Conjugated DOX-Fe3O4/P(NIPAM-AA-MAPEG) Nanogel System for HER2-Targeted Breast Cancer Treatment and Magnetic Resonance Imaging

It is essential to synthesize a "diagnosis and therapy" integration nanocarrier for magnetic resonance imaging-guided breast cancer-targeted chemotherapy. Here, we report Fe₃O₄/P(NIPAM-AA-MAPEG) nanogels (MNLs) based on in situ loading of doxorubicin (DOX) by miniemulsion polymerization. Especially, propyl acrylic acid (AA) moieties were introduced to absorb DOX by electrostatic interactions and conjugated with the antibody herceptin (HER) through the amino-carboxyl coupling reaction. The size and morphology of MNLs could be adjusted by varying the polymerization parameters, such as the monomer feeding ratio, ferrofluid content, and cross-linker content. The MNLs showed superior stability in a physiological environment, but their structures were destroyed in an acidic environment to accelerate DOX release. The dissociation of the HER-DOX-MNLs accelerated the delivery of DOX and enhanced the therapeutic effects. The studies exhibited that the HER-DOX-MNLs could inhibit the tumor growth. In addition, the MNLs with a high magnetic content had the potential advantages in magnetic resonance imaging (MRI) of breast cancer diagnosis. The dual-targeted pH-responsive nanogels were successfully designed as a multifunctional nanocarrier for realizing HER2-positive breast cancer chemotherapy and diagnostics.

Ultra pH-sensitive nanocarrier based on Fe2O3/chitosan/montmorillonite for quercetin delivery

Harmful side effects of the chemotherapeutic agent have been investigated in many recent studies. Since Fe₂O₃ nanoparticles have proper porosity, they are capable for loading noticeable amount of drugs and controlled release. We developed Fe₂O₃/chitosan/montmorillonite nanocomposite. Quercetin (QC) nanoparticles, which have fewer side effects than chemical anti-tumor drugs, were encapsulated in the synthesized nanocarrier and were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), and zeta potential. For quercetin, the encapsulation efficiency and the loading efficiency of the drug in Fe₂O₃-CS-MMT@QC were found to be about 94% and 57%, respectively. The release profile of QC in different mediums indicated pH-dependency and controlled release of the nanocomposite, adhering to The Weibull kinetic model. Biocompatibility of the Fe₂O₃/CS/MMT nanoparticles against the MCF-7 cells was shown by MTT assay and confirmed by flow cytometry. These data demonstrate that the designed Fe₂O₃-CS-MMT@QC would have potential drug delivery to treat cancer cells.

Thermoresponsive Chitosan-Grafted-Poly(N-vinylcaprolactam) Microgels via Ionotropic Gelation for Oncological Applications

Microgels can be considered soft, porous and deformable particles with an internal gel structure swollen by a solvent and an average size between 100 and 1000 nm. Due to their biocompatibility, colloidal stability, their unique dynamicity and the permeability of their architecture, they are emerging as important candidates for drug delivery systems, sensing and biocatalysis. In clinical applications, the research on responsive microgels is aimed at the development of "smart" delivery systems that undergo a critical change in conformation and size in reaction to a change in environmental conditions (temperature, magnetic fields, pH, concentration gradient). Recent achievements in biodegradable polymer fabrication have resulted in new appealing strategies, including the combination of synthetic and natural-origin polymers with inorganic nanoparticles, as well as the possibility of controlling drug release remotely. In this review, we provide a literature review on the use of dual and multi-responsive chitosan-grafted-poly-(N-vinylcaprolactam) (CP) microgels in drug delivery and oncological applications.

Self-assembled magnetic polymeric micelles for delivery of quercetin: Toxicity evaluation on isolated rat liver mitochondria

Multifunctional nanocarriers as a promising platform could provide numerous opportunities in the field of drug delivery. Drug carriers loaded with both magnetic nanoparticles (MNPs) and therapeutic agents would allow the combination of chemotherapy with the possibility of monitoring or controlling the distribution of the nano vehicles in the body which may improve the effectiveness of the therapy. Furthermore, by applying these strategies, triggering drug release and/or synergistic hyperthermia treatment are also reachable. This study aimed to explore the potential of the quercetin (QUR) loaded magnetic nano-micelles for improving drug bioavailability while reducing the drug adverse effects. The bio-safety of developed QUR loaded magnetic nano-micelles (QMNMs) were conducted via mitochondrial toxicity using isolated rat liver mitochondria including glutathione (GSH), malondialdehyde (MDA), and the ferric reducing ability of plasma (FRAP). QMNMs with a mean particle size of 85 nm (PDI value of 0.269) and great physical stability were produced. Also, TEM images indicated that the prepared QMNMs were semi-spherical in shape. These findings also showed that the constructed QMNMs, as a pH-sensitive drug delivery system, exhibited a stable and high rate of QUR release under mildly acidic conditions pH (5.3) compared to neutral pH (7.4). The most striking result to emerge from the data is that an investigation of various mitochondrial functional parameters revealed that both QMNMs and QUR have no specific mitochondrial toxicity. Altogether, these results offer overwhelming evidence for the bio-safety of QMNMs and might be used as an effective drug delivery system for targeting and stimuli-responsive QUR delivery.

Magnetic nanostructured lipid carrier for dual triggered curcumin delivery: Preparation, characterization and toxicity evaluation on isolated rat liver mitochondria

In this research, magnetic nanostructured lipid carriers (Mag-NLCs) were synthesized for curcumin (CUR) delivery. NLCs are drug-delivery systems prepared by mixing solid and liquid (oil) lipids. For preparation of NLCs, cetylpalmitate was selected as solid lipid and fish oil as liquid lipid. CUR-Mag-NLCs were prepared using high-pressure homogenization technique and were characterized by methods including X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and dynamic light scattering (DLS). The CUR-Mag-NLCs were developed as a particle with a size of 140 ± 3.6 nm, a polydispersity index of 0.196, and a zeta potential of -22.6 mV. VSM analysis showed that the CUR-Mag-NLCs have excellent magnetic properties. Release rate of the drug was higher at 42 °C than 37 °C, indicating that release of the synthesized nanoparticles is temperature-dependent. Evaluation of mitochondrial toxicity was done using the isolated rats liver mitochondria including glutathione (GSH), malondialdehyde (MDA), and the ferric- reducing ability of plasma (FRAP) assays to study biosafety of the CUR-Mag-NLCs. Results of In vitro study on the isolated mitochondria revealed that both CUR-Mag-NLCs and curcumin have no specific mitochondrial toxicity.

PVP Surface-protected silica coated iron oxide nanoparticles for MR imaging application

This paper proposed an engineered mesoporous silica-coated Fe₃O₄ nanoparticle, PVPMSFe, prepared by a sol-gel/surface-protected etching mechanism as an MRI T2 contrast agent. To this end, the structural characterization of the nanocomposite was performed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, VSM, thermogravimetric analysis (TGA), TEM, FESEM, and energy-dispersive X-ray scanning electron microscopy (EDS). The findings show that the synthesized nanocomposite has a mesoporous structure with an average particle size of 11.8 nm and excellent magnetization properties. The biocompatibility of PVPMSFe was investigated by MTT assay and hemolysis assay of red blood cells and the results indicate that PVPMSFe has favorable biocompatibility. Besides, the effect of PVPMSFe was assessed with MRI relaxivity measurement (T2 signal). Regarding the in vitro MRI relaxivity measurements outputs (r₂=144.4), PVPMSFe can attenuate the T2 signal of MRI, perfectly which makes it an efficient T2 contrast agent.

Inulin-Coated Iron Oxide Nanoparticles: A Theranostic Platform for Contrast-Enhanced MR Imaging of Acute Hepatic Failure

The present study introduces a superparamagnetic nanocomposite, Fe-Si-In, as a T2 magnetic resonance imaging (MRI) contrast agent with a core of iron oxide nanoparticles and a nonporous silica inner shell/carboxymethyl inulin outer shell. Due to its core/shell properties, the structure characterization, biocompatibility, and performance in MRI, as well as its potential as a drug delivery system, were thoroughly evaluated. The results have shown that the synthesized nanocomposite possesses excellent biocompatibility and acceptable magnetization (M_s = 20 emu g^-1). It also has the potential to be a nanocarrier for drug delivery purposes, as evidenced by the results of curcumin administration studies. The developed nanocomposite has shown excellent performance in MRI, while the in vitro relaxivity measurements reveal a stronger T2 relaxivity (r₂ = 223.2 ms) compared to the commercial samples available in the market. Furthermore, the in vivo MRI studies demonstrate an excellent contrast between injured livers and normal ones in rats which again upholds the high performance of Fe-Si-In in MRI diagnostics.

In vitro evaluation of curcumin-loaded chitosan-coated hydroxyapatite nanocarriers as a potential system for effective treatment of cancer

Nanotechnology has many potential applications in cancer treatment. For example, nano-drug delivery systems (NDDS) with high bioavailability, biodegradability, and biocompatibility have been developed, in order to increase the therapeutic effects of anticancer drugs. Among these NDDS, high-performance hydroxyapatite (HA) nanoparticles are rapidly advancing in the targeted cancer treatment due to their numerous benefits. Curcumin is an herbal metabolite that acts as a chemical inhibitor through the inhibition of tumor cells and the progression of many cancers. However, the poor bioavailability of curcumin is the most important challenge in using this substance. In this study, HA nanoparticles coated by chitosan were used as a pH-sensitive biopolymer to improve the efficiency and bioavailability of curcumin. For this purpose, HA nanoparticles were first synthesized by the sol-gel method. Then, a layer of chitosan was coated on it, and the curcumin drug was encapsulated in the nanocarrier, under controlled conditions. Techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the nanocarriers. In the second part, nano-drugs prepared by various bioassays were examined. For this purpose, the rate of cytotoxicity by the methyl-thiazol-tetrazolium (MTT) assay and the rate of apoptosis induction by the acridine orange and ethidium bromide (AO/EB) staining method on the brain carcinoma U87MG cell line were investigated.

One-pot hydrothermal synthesis of a magnetic hydroxyapatite nanocomposite for MR imaging and pH-Sensitive drug delivery applications

Synthetic hydroxyapatite (HA) due to its high biocompatibility, anti-inflammatory properties, high stability, and a flexible structure in combination with magnetic nanoparticles has the strong potential to be used in modern medicine including tissue engineering, imaging, and drug delivery. Herein, a hydrothermal process was used to prepare magnetite nanoparticles dispersed on the hydroxyapatite nanorods with cetyltrimethylammonium bromide (CTAB) as a surfactant. Characterization study of the synthesized iron oxide-hydroxyapatite (IO-HA) nanocomposite was performed by FT-IR spectroscopy, X-ray powder diffraction, energy dispersive X-Ray analysis (EDX) for elemental mapping, transmission electron microscopy, and vibrating sample magnetometer. Then, the biocompatibility of the synthesized nanocomposite studied by 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay and hemocompatibility assay. Focus on this point, curcumin loaded IO-HA (Cur@IO-HA) was developed for exploring the pH-sensitivity of the drug carrier and then evaluating its cellular uptake. The in vitro efficacy of the synthesized nanocomposites as a magnetic resonance imaging (MRI) contrast agent was also investigated. Our results showed that IO-HA nanocomposite is non-cytotoxic and hemocompatible as well as a good pH-sensitive drug carrier and a favorable MRI T2 contrast agent. Comparing to the free curcumin, Cur@IO-HA displayed a good cellular uptake. Taking into account the above issues, IO-HA nanocomposite has the most potential for application as a theranostic MRI contrast agent.

Advancement in nanogel formulations provides controlled drug release

Nanogels are currently considered as promising nanosized drug delivery carriers. Nanogels are made of a crosslinked polymeric network which could encapsulate both hydrophilic and hydrophobic drugs due to their tunable nature. The ability of nanogels to control drug release is vastly described in the literature and researchers are consistently improving the control of drug release from nanogel by designing new polymers having specific sensitivity to a chemical or physical stimulus. In this review, we briefly discuss the definition of nanogels, their release profiles, their specific gel-based characteristics and the pathways of dug release from nanogels. We have focused on the stimuli responsive nanogels and their release profile. This compilation opens the window for understanding the influence of chemical composition and design of various nanogel on their release in the presence and absence of corresponding stimuli such as temperature, pH, enzymes and others. The uniqueness of this review is that it highlights the data of release profiles in terms of the different nanogel composition and triggers. It also points the high potential of nanogels in the list of candidates for drug delivery systems, thanks to their properties regarding drug encapsulation and release, combined advantages of nano-size and swelling characteristics of hydrogel.

Magnetic nanoparticles decorated with PEGylated curcumin as dual targeted drug delivery: Synthesis, toxicity and biocompatibility study

The problems associated with hydrophobic anticancer drugs are among the most important challenges to achieve efficient therapeutics for cancer treatment. In this study, PEGylated curcumin was used as the surface modification of magnetic nanoparticles (MNP@PEG-Cur) in order to simultaneously take advantage of magnetic targeting characteristic of nanoparticles and PEG conjugated drug. Curcumin was conjugated through EDC/NHS chemistry to the PEG hydroxyl functional groups, and then physically decorated on the surface of magnetic nanoparticles (MNP). The analysis of the conjugate and nanoparticles by FT-IR, ¹HNMR, FE-SEM, TEM, EDX, TGA and VSM confirmed the successful synthesis and proper physicochemical properties of MNP@PEG-Cur nanoparticles. The carrier showed pH dependent drug release profile with higher drug release at acidic media (pH = 5.4) compared to neural condition (pH = 7.4). In addition, LD₅₀ and hemolysis assay confirmed the biocompatibility of MNP@PEG-Cur. The cell viability assay also revealed that neither carrier, nor curcumin-loaded nanoparticles are cytotoxic at physiologic pH (7.4).

Polymers, responsiveness and cancer therapy

A single outcome in a biological procedure at the time of cancer therapy is due to multiple changes happening simultaneously. Hence to mimic such complex biological processes, an understanding of stimuli responsiveness is needed to sense specific changes and respond in a predictable manner. Such responses due to polymers may take place either simultaneously at the site or in a sequential manner from preparation to transporting pathways to cellular compartments. The present review comprehends the stimuli-responsive polymers and multi-responsiveness with respect to cancer therapy. It focuses on the exploitation of different stimuli like temperature, pH and enzymes responsiveness in a multi-stimuli setting. Nanogels and micelles being two of the most commonly used responsive polymeric carriers have also been discussed. The role of multiple stimuli delivery system is significant due to multiple changes happening in the near surroundings of cancer cells. These responsive materials are able to mimic some biological processes and recognize at the molecular level itself to manipulate development of custom-designed molecules for targeting cancer cells.