Biological evaluation of surface-modified magnetic nanoparticles as a platform for colon cancer cell theranostics

Recent Advances in the Development and Utilization of Nanoparticles for the Management of Malignant Solid Tumors

The purpose of nanotechnology-based drug delivery systems or novel drug delivery systems is to improve the effectiveness of therapy, and their promising properties have led to their increasing significance in the management of cancer. The researchers have primarily focused on designing novel nanocarriers, like nanoparticles (NPs), that can effectively deliver drugs to target cells and respond specifically to conditions particular to cancer. Whether passive or active targeting, these nanocarriers can deliver therapeutic cargoes to the tumor site to release the drug from the drug delivery systems. The purpose of this study is to provide recent scientific literature and key findings to researchers as well as the scientific community from the medical and pharmaceutical domains by reporting current advancements in the development of NPs for the treatment of different malignant solid tumors, such as colorectal, pancreatic, prostate, and cervical cancer.

Insights into the time-course cellular effects triggered by iron oxide nanoparticles by combining proteomics with the traditional pharmacology strategy

In recent years, a number of initially approved magnetic iron oxide nanoparticle (IONP)-based nano-medicines have been withdrawn due to the obscure nano-bio effects. Therefore, there is an urgent need to study the cellular effects triggered by IONPs on cells. In this study, we investigate the time-course cellular effects on the response of RAW 264.7 cells caused by Si-IONPs via pharmacological and mass spectrometry-based proteomics techniques. Our results revealed that Si-IONPs were internalized by clathrin-mediated endocytosis within 1 hour, and gradually degraded in endolysosomes over time, which might influence autophagy, oxidative stress, innate immune response, and inflammatory response after 12 hours. Our research provides a necessary assessment of Si-IONPs for further clinical treatment.

Recent trends in preparation and biomedical applications of iron oxide nanoparticles

The iron oxide nanoparticles (IONPs), possessing both magnetic behavior and semiconductor property, have been extensively used in multifunctional biomedical fields due to their biocompatible, biodegradable and low toxicity, such as anticancer, antibacterial, cell labelling activities. Nevertheless, there are few IONPs in clinical use at present. Some IONPs approved for clinical use have been withdrawn due to insufficient understanding of its biomedical applications. Therefore, a systematic summary of IONPs' preparation and biomedical applications is crucial for the next step of entering clinical practice from experimental stage. This review summarized the existing research in the past decade on the biological interaction of IONPs with animal/cells models, and their clinical applications in human. This review aims to provide cutting-edge knowledge involved with IONPs' biological effects in vivo and in vitro, and improve their smarter design and application in biomedical research and clinic trials.

Antibody-Loaded Nanoplatforms for Colorectal Cancer Diagnosis and Treatment: An Update

At present, colorectal cancer (CRC) is the second deadliest type of cancer, partly because a high percentage of cases are diagnosed at advanced stages when tumors have already metastasized. Thus, there is an urgent need to develop novel diagnostic systems that allow early detection as well as new therapeutic systems that are more specific than those currently available. In this context, nanotechnology plays a very important role in the development of targeted platforms. In recent decades, many types of nanomaterials with advantageous properties have been used for nano-oncology applications and have been loaded with different types of targeted agents, capable of recognizing tumor cells or biomarkers. Indeed, among the different types of targeted agents, the most widely used are monoclonal antibodies, as the administration of many of them is already approved by the main drug regulatory agencies for the treatment of several types of cancer, including CRC. In this way, this review comprehensively discusses the main drawbacks of the conventional screening technologies and treatment for CRC, and it presents recent advances in the application of antibody-loaded nanoplatforms for CRC detection, therapy or theranostics applications.

Nanotechnology in Cancer Diagnosis and Treatment

Traditional cancer diagnosis has been aided by the application of nanoparticles (NPs), which have made the process easier and faster. NPs possess exceptional properties such as a larger surface area, higher volume proportion, and better targeting capabilities. Additionally, their low toxic effect on healthy cells enhances their bioavailability and t-half by allowing them to functionally penetrate the fenestration of epithelium and tissues. These particles have attracted attention in multidisciplinary areas, making them the most promising materials in many biomedical applications, especially in the treatment and diagnosis of various diseases. Today, many drugs are presented or coated with nanoparticles for the direct targeting of tumors or diseased organs without harming normal tissues/cells. Many types of nanoparticles, such as metallic, magnetic, polymeric, metal oxide, quantum dots, graphene, fullerene, liposomes, carbon nanotubes, and dendrimers, have potential applications in cancer treatment and diagnosis. In many studies, nanoparticles have been reported to show intrinsic anticancer activity due to their antioxidant action and cause an inhibitory effect on the growth of tumors. Moreover, nanoparticles can facilitate the controlled release of drugs and increase drug release efficiency with fewer side effects. Nanomaterials such as microbubbles are used as molecular imaging agents for ultrasound imaging. This review discusses the various types of nanoparticles that are commonly used in cancer diagnosis and treatment.

Magneto-Fluorescent Mesoporous Nanocarriers for the Dual-Delivery of Ofloxacin and Doxorubicin to Tackle Opportunistic Bacterial Infections in Colorectal Cancer

Cancer-related opportunistic bacterial infections are one major barrier for successful clinical therapies, often correlated to the production of genotoxic factors and higher cancer incidence. Although dual anticancer and antimicrobial therapies are a growing therapeutic fashion, they still fall short when it comes to specific delivery and local action in in vivo systems. Nanoparticles are seen as potential therapeutic vectors, be it by means of their intrinsic antibacterial properties and effective delivery capacity, or by means of their repeatedly reported modulation and maneuverability. Herein we report on the production of a biocompatible, antimicrobial magneto-fluorescent nanosystem (NANO3) for the delivery of a dual doxorubicin-ofloxacin formulation against cancer-related bacterial infections. The drug delivery capacity, rendered by its mesoporous silica matrix, is confirmed by the high loading capacity and stimuli-driven release of both drugs, with preference for tumor-like acidic media. The pH-dependent emission of its surface fluorescent SiQDs, provides an insight into NANO3 surface behavior and pore availability, with the SiQDs working as pore gates. Hyperthermia induces heat generation to febrile temperatures, doubling drug release. NANO3-loaded systems demonstrate significant antimicrobial activity, specifically after the application of hyperthermia conditions. NANO3 structure and antimicrobial properties confirm their potential use in a future dual anticancer and antimicrobial therapeutical vector, due to their drug loading capacity and their surface availability for further modification with bioactive, targeting species.

Advanced Magnetic Resonance Imaging (MRI) Techniques: Technical Principles and Applications in Nanomedicine

Simple Summary

Magnetic Resonance Imaging (MRI) is a consolidated imaging tool for the multiparametric assessment of tissues in various pathologies from degenerative and inflammatory diseases to cancer. In recent years, the continuous technological evolution of the equipment has led to the development of sequences that provide not only anatomical but also functional and metabolic information. In addition, there is a growing and emerging field of research in clinical applications using MRI to exploit the diagnostic and therapeutic capabilities of nanocompounds. This review illustrates the application of the most advanced magnetic resonance techniques in the field of nanomedicine.

Abstract

In the last decades, nanotechnology has been used in a wide range of biomedical applications, both diagnostic and therapeutic. In this scenario, imaging techniques represent a fundamental tool to obtain information about the properties of nanoconstructs and their interactions with the biological environment in preclinical and clinical settings. This paper reviews the state of the art of the application of magnetic resonance imaging in the field of nanomedicine, as well as the use of nanoparticles as diagnostic and therapeutic tools, especially in cancer, including the characteristics that hinder the use of nanoparticles in clinical practice.

Anti-microbial and anti-cancer activities of Mn0.5Zn0.5DyxFe2-xO4 (x ≤ 0.1) nanoparticles

Combining two or more nanoparticles is a promising approach. Previously we have reported synthesis of nanoparticles Dysprosium (Dy) substituted with manganese (Mn) zinc (Zn) by using ultrasonication method. The five different nanoparticles (NPs) Mn0.5Zn0.5DyxFe2-xO4 (x ≤ 0.1) have been structurally and morphologically characterized but there is no report on the biological application of these NPs. In the present study, we have examined the anti-cancer, anti-bacterial, and anti-fungal activities of Mn0.5Zn0.5DyxFe2-xO4 (x ≤ 0.1) NPs. Human colorectal carcinoma cells (HCT-116) were tested with different concentrations of NPs by using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. In addition, the impact of NPs was also examined on normal cells such as human embryonic kidney cells, HEK-293. After 48 h of treatment, Mn0.5Zn0.5DyxFe2-xO4 NPs (x = 0.02, 0.04 and 0.06) showed no inhibitory action on cancer cell's growth and proliferation, whereas Mn0.5Zn0.5DyxFe2-xO4 NPs (x = 0.08 and 0.1) showed profound inhibitory action on cancer cell's growth and proliferation. However, the treatment of Mn0.5Zn0.5DyxFe2-xO4 NPs on the normal cells (HEK-293) did not show cytotoxic or inhibitory action on HEK-293 cells. The treatment of Mn0.5Zn0.5DyxFe2-xO4 NPs (x ≤ 0.1) also inhibited both the bacteria (Escherichia coli ATCC35218 and Staphylococcus aureus) with lowest MIC and MBC values of 4 and 8 mg/mL and fungus (Candida albicans) with MIC and MFC values of 4 and 8 mg/mL on treatment with x = 0.08 and 0. 1.

Cancer Nanotheranostics: A Nanomedicinal Approach for Cancer Therapy and Diagnosis

The panorama of cancer treatment has taken a considerable leap over the last decade with the advancement in the upcoming novel therapies combined with modern diagnostics. Nanotheranostics is an emerging science that holds tremendous potential as a contrivance by integrating therapy and imaging in a single probe for cancer diagnosis and treatment thus offering the advantage like tumor-specific drug delivery and at the same time reduced side effects to normal tissues. The recent surge in nanomedicine research has also paved the way for multimodal theranostic nanoprobe towards personalized therapy through interaction with a specific biological system. This review presents an overview of the nano theranostics approach in cancer management and a series of different nanomaterials used in theranostics and the possible challenges with future directions.

Trends in targeted delivery of nanomaterials in colon cancer diagnosis and treatment

Colon cancer is an adenocarcinoma, which subsequently develops into malignant tumors, if not treated properly. The current colon cancer therapy mainly revolves around chemotherapy, radiotherapy and surgery, but the search continues for more effective interventions. With the advancement of nanoparticles (NPs), it is now possible to diagnose and treat colon cancers with different types, shapes, and sizes of NPs. Nanoformulations such as quantum dots, iron oxide, polymeric NPs, dendrimers, polypeptides, gold NPs, silver NPs, platinum NPs, and cerium oxide have been either extensively used alone or in combination with other nanomaterials or drugs in colon cancer diagnosis, and treatments. These nanoformulations possess high biocompatibility and bioavailability, which makes them the most suitable candidates for cancer treatment. The size and shape of NPs are critical to achieving an effective drug delivery in cancer treatment and diagnosis. Most NPs currently are under different testing phases (in vitro, preclinical, and clinical), whereas some of them have been approved for therapeutic applications. We have comprehensively reviewed the recent advances in the applications of NPs-based formulations in colon cancer diagnosis and treatment.

Triumph against cancer: invading colorectal cancer with nanotechnology

INTRODUCTION

Recent statistics have reported colorectal cancer (CRC) as the second leading cause of cancer-associated deaths in the world. Early diagnosis of CRC may help to reduce the mortality and associated complications. However, the conventional diagnostic techniques often lead to misdiagnosis, fail to differentiate benign from malignant tissue or diagnose only at an advanced stage. For the treatment of CRC, surgery, chemotherapy, immunotherapy, and radiotherapy have been employed. However, the quality of living of the CRC patients is highly compromised after employing current therapeutic approaches owing to the toxicity issues and relapse.

AREA COVERED

This review accentuates the molecular mechanisms involved in the pathogenesis, stages of CRC, conventional approaches for diagnosis and therapy of CRC and the issues confronted thereby. It provides an outlook on the advantages of employing nanotechnology-based approaches for prevention, early diagnosis, and treatment of CRC.

EXPERT OPINION

Employing nanotechnology-based approaches has demonstrated promising outcomes in the prevention, diagnosis, and treatment of CRC. Nanotechnology-based approaches can surmount the major drawbacks of traditional diagnostic and therapeutic approaches. Nanotechnology bestows the advantage of early detection of CRC which helps to undertake instant steps for offering efficient therapy and reducing the mortality rates. For the treatment of CRC, nanocarriers offer the benefit of achieving controlled drug release, improved drug bioavailability, enhanced tumor targetability and reduced adverse effects.

Glycosylation of anthocyanins enhances the apoptosis of colon cancer cells by handicapping energy metabolism

BACKGROUND

While anthocyanins are proven to be effective in inhibiting tumour cell proliferation, the underlying mechanisms remain unclear. This research aims to explore the glycosylation of anthocyanins in the tumour inhibitory effects and the potential mechanism.

METHODS

The tumour inhibitory effect on mouse colon cancer cells (MC38) was examined by MTT and flow cytometric analyses. The inhibitory pathway of anthocyanin was explored by assessment of tumour cell mitochondrial membrane potential (MMP), the caspase-3 and caspase-9 activity, as well as the cell energy metabolism in terms of the glucose uptake, the NAD+/NADH ratio and the ATP level.

RESULTS

We found that 500 μM bilberry anthocyanins extract (BAE) induced 48.1% mitochondrial damage, activated the downstream caspase cascade to form apoptotic bodies (caspase-3 activity increased by 169%, caspase-9 activity increased by 186%), and inhibited cell proliferation (survival rate: 55.97%, 24 h). In contrast, the same concentration of anthocyanidin (cyanidin) led to marginal mitochondrial damage (only 9.85%) and resulted in little inhibition of MC38 cells (survival rate: 86.84%, 24 h). For cells incubated with 500 μM BAE, reactive oxygen species (ROS) decreased by 53.8%, but the ratio of NAD+/NADH increased to 3.67, demonstrating that the mitochondrial damage was induced by blocking energy metabolism. Furthermore, cell energy metabolism is related to glucose uptake since the presence of 200 μM GLUT1 inhibitor substantially enhanced the inhibitory effects of cyanidin-3-O-glucoside (Cy-3-Glu) at 500 μM (survival rate: 51.08%, 24 h).

CONCLUSIONS

The study suggested that the glycosides of anthocyanins might handicap glucose transport and inhibit energy metabolism, which, in turn, led to mitochondrial damage and apoptosis of tumour cells.

In vitro Biological Tests as the First Tools To Validate Magnetic Nanotheranostics for Colorectal Cancer Models

Colorectal cancer (CRC) remains a leading cause of cancer death. Nanotechnology has focused on reaching more effective treatments. In this concern, magnetic nanoparticles (MNPs) have been studied for a wide range of biomedical applications related to CRC, such as diagnostic imaging, drug delivery and thermal therapy. However, limited research is currently found in the open literature that refers to nanosystems combining all these mentioned areas (theranostics). When developing nanosystems intended as theranostics applied to CRC, possible variations between patients must be considered. Therefore, multiple in vitro assays are required as guidance for future preclinical and clinical trials. The objective of this contribution is to evaluate the available and recent literature regarding the interactions of MNP and CRC models, aiming to critically analyze the information given by the commonly used assays and evaluate the data provided by each one with a view to implementing this novel technology in CRC diagnostics and therapy.

Synthesis of niobium substituted cobalt-nickel nano-ferrite (Co0.5Ni0.5NbxFe2-xO4 (x ≤ 0.1) by hydrothermal approach show strong anti-colon cancer activities

The combination of two or more nanoparticles found to be effective strategy to synthesize nanocomposites for better drug delivery and treatment. In the present study, we have combined cobalt (Co), nickel (Ni), niobium (Nb), and iron oxide (Fe₂O₄) and prepared niobium substituted cobalt-nickel nano-ferrite nanocomposites (Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) by using hydrothermal approach. We have characterized the structure and morphology of nanocomposites by using XRD, EDX, TEM and SEM methodologies. We have examined the impact of nanocomposites (Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) on cancerous cells (human colorectal carcinoma cells, HCT-116) by using MTT assay. We have also checked the impact of nanocomposites on normal and non-cancerous cells (human embryonic kidney cells, HEK-293) to confirm the specificity of their actions. Post- 48 h treatment of Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) led to dose-dependent inhibition of cancer cells growth and proliferation. However, no cytotoxic effect was observed on the normal cells (HEK-293). In addition, DAPI stained nuclear DNA staining analysis demonstrates that the Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) treatment also caused nuclear DNA disintegration which is the marker for programmed cell death. These results demonstrate that synthesized nanocomposites Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) selectively target the colon cancer cells and induce cancer cell death.Communicated by Ramaswamy H. Sarma.

Enhancement of Magnetic Hyperthermia by Mixing Synthetic Inorganic and Biomimetic Magnetic Nanoparticles

In this work we report on the synthesis and characterization of magnetic nanoparticles of two distinct origins, one inorganic (MNPs) and the other biomimetic (BMNPs), the latter based on a process of bacterial synthesis. Each of these two kinds of particles has its own advantages when used separately with biomedical purposes. Thus, BMNPs present an isoelectric point below neutrality (around pH 4.4), while MNPs show a zero-zeta potential at pH 7, and appear to be excellent agents for magnetic hyperthermia. This means that the biomimetic particles are better suited to be loaded with drug molecules positively charged at neutral pH (notably, doxorubicin, for instance) and releasing it at the acidic tumor environment. In turn, MNPs may provide their transport capabilities under a magnetic field. In this study it is proposed to use a mixture of both kinds of particles at two different concentrations, trying to get the best from each of them. We study which mixture performs better from different points of view, like stability and magnetic hyperthermia response, while keeping suitable drug transport capabilities. This composite system is proposed as a close to ideal drug vehicle with added enhanced hyperthermia response.

pH responsible and fluorescent Cy5.5-PEG-g-A-HA/CDDP complex nanoparticles: synthesis, characterization, and application for targeted drug delivery

Clinical application of cisplatin (CDDP) against various solid tumors is often limited due to its poor selectivity and severe side effect. Considering this, in our study, CDDP was incorporated in fluorescent PEG amine grafted aldehyde hyaluronic acid by imine bond and metal ion coordination bond linking and formed a complex, the complex was then self-assembled into nanoparticles in water simply. FT-IR, XRD, DLS and SEM analysis demonstrated that the nanoparticles were prepared successfully and exhibited a spherical structure with size ranged from 216.4 to 372.3 nm in diameter. CDDP releasing from the nanoparticles was in a controlled manner, and had faster release rate at lower pH, indicating the nanoparticles were responsive to tumor micro-acid environment. Since fluorescent Cy5.5 and targeting hyaluronic acid existed on the surface of the nanoparticles, CLSM images clearly showed that the nanoparticles could target and internalize into HeLa cells, and then inhibited the growth of HeLa cells. In addition, MTT, AO-EB staining, and hemolysis assay showed that the nanoparticles had good cyto-/hemo-compatibility. Hence, the nanoparticles had the potential to be used for cancer therapy and diagnosis. The further in vivo experiment will be shown in the next work. pH responsible and fluorescent Cy5.5-PEG-g-A-HA/CDDP complex nanoparticles were facilely fabricated for controlled and targeted delivery of CDDP.

A Systematic Study on Design Initiation of Conceptual 3DPVS

An important product in biomedical and biomimetic engineering is the 3D scaffold, which mimics the real tissue in vitro to achieve the external cultivation of cells. The difference between the 3D scaffold and other biomimetic products lies in the fact that the former mimics the internal features of tissue, while the latter generally approximates the external traits of biological beings. In the field of scaffold engineering, the 3D printed vibratory scaffold, 3DPVS, has been proposed as a present-to-future novel scaffold product, and it currently stays at the stage of conceptual development. To achieve the novel design of the conceptual 3DPVS, a conceptual design process has been established by authors in their previous work, which contain three main stages, namely the design initiation, concept generation, and concept evaluation. In terms of design initiation, it is a ‘must-accomplish’ stage which generates outputs for both the subsequent concept generation and evaluation. Work of design initiation therefore is of significant value and it consists of several tasks; that is, conducting a thorough literature review, summarizing the fundamental issues preparing the general conceptual design, studying the multi-characterization of the 3DPVS, putting forward the potential base model(s), as well as indicating the ideality of the scaffold and establishing potential ideal model(s) for the 3DPVS. In this paper, design initiation will be chiefly focused upon these essential aspects to be discussed, work of which is expected to be useful in establishing a solid ground for future innovation work of the 3DPVS.

Synthesis, characterization and in vitro validation of a magnetic zeolite nanocomposite with T2-MRI properties towards theranostic applications

This study focusses on the development of a magnetic zeolite nanocomposite as a suitable platform towards the design of a theranostic system. Herein, we explored its ability to act as a T₂-MRI contrast enhancer when magnetic nanoparticles are incorporated in its structure.

Scavenging of reactive oxygen species by phenolic compound-modified maghemite nanoparticles

Maghemite (γ-Fe₂O₃) nanoparticles obtained through co-precipitation and oxidation were coated with heparin (Hep) to yield γ-Fe₂O₃@Hep, and subsequently with chitosan that was modified with different phenolic compounds, including gallic acid (CS-G), hydroquinone (CS-H), and phloroglucinol (CS-P), to yield γ-Fe₂O₃@Hep-CS-G, γ-Fe₂O₃@Hep-CS-H, and γ-Fe₂O₃@Hep-CS-P particles, respectively. Surface modification of the particles was analyzed by transmission electron microscopy, dynamic light scattering, attenuated total reflection Fourier transform infrared spectroscopy, and thermogravimetric analysis. Magnetic measurements indicated that the polymer coating does not affect the superparamagnetic character of the iron oxide core. However, magnetic saturation decreased with increasing thickness of the polymer coating. The antioxidant properties of the nanoparticles were analyzed using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Cellular uptake and intracellular antioxidant activity of the particles were evaluated by an iron assay and flow cytometry, respectively, using L-929 and LN-229 cells. Compared to the control, the phenolic modification significantly reduced intracellular reactive oxygen species (ROS) levels to 35-56%, which was associated with a 6-8-times higher cellular uptake in L-929 cells and a 21-31-times higher cellular uptake in LN-229 cells. In contrast, γ-Fe₂O₃@Hep particles induced a 3.8-times and 14.9-times higher cellular uptake without inducing antioxidant activity. In conclusion, the high cellular uptake and the antioxidant properties associated with the phenolic moieties in the modified particles allow for a potential application in biomedical areas.

Cytotoxicity of doxorubicin-conjugated poly[N-(2-hydroxypropyl)methacrylamide]-modified γ-Fe2O3 nanoparticles towards human tumor cells

Doxorubicin-conjugated magnetic nanoparticles containing hydrolyzable hydrazone bonds were developed using a non-toxic poly[N-(2-hydroxypropyl)methacrylamide] (PHPMA) coating, which ensured good colloidal stability in aqueous media and limited internalization by the cells, however, enabled adhesion to the cell surface. While the neat PHPMA-coated particles proved to be non-toxic, doxorubicin-conjugated particles exhibited enhanced cytotoxicity in both drug-sensitive and drug-resistant tumor cells compared to free doxorubicin. The newly developed doxorubicin-conjugated PHPMA-coated magnetic particles seem to be a promising magnetically targeted vehicle for anticancer drug delivery.

Differential effect of polyvinylpyrrolidone-coated superparamagnetic iron oxide nanoparticles on BT-474 human breast cancer cell viability

Polyvinylpyrrolidone superparamagnetic iron oxide nanoparticles (PVP-SPIONs) have unique properties. Due to these characteristics, PVP-SPIONs have been used in several medical applications such as magnetic resonance imaging (MRI) contrast agent or drug delivery system. However, a more comprehensive understanding of the environmental safety of PVP-SPIONs is vital for consumption of these nanomaterials. In this study, we describe the effects of PVP-SPIONs on cell viability of the BT-474 human breast cancer cells. Cell viability of the BT-474 cells treated with PVP-SPIONs (10-800 μg/ml) was assessed by MTT assay. MRC-5 cell line was used as a control. Quantitative real-time PCR was performed to investigate the mRNA expression levels of apoptotic (caspase 3) and anti-apoptotic (BCL2) genes Confluent BT-474 monolayers exposed to PVP-SPIONs showed biphasic effects on cell proliferation. PVP-SPIONs at 10-100 μg /ml promote proliferation of BT-474 cells but not the MRC-5 cells. At higher dosage, PVP-SPIONs have toxicity on BT-474 cells. The results of real-time PCR was in line with MTT assay. The increase of cell proliferation at low PVP-SPIONs concentrations is different from what would be expected for these nanoparticles. Our results suggest that more attentions are needed to ensure the safer use of SPION in nanomedicine.