Protein-passivated Fe(3)O(4) nanoparticles: low toxicity and rapid heating for thermal therapy

Non-invasive Diagnosis and Postoperative Evaluation of Carotid Artery Stenosis by BSA-Gd2O3 Nanoparticles-Based Magnetic Resonance Angiography

Contrast-enhanced magnetic resonance angiography is a powerful and effective method to accurately diagnose carotid artery stenosis. Small molecular gadolinium (Gd)-based agents have reliable signal enhancement, but their short circulating time may result in a loss of image resolution due to insufficient vascular filling or contrast agent emptying. Here, we report an MRA imaging approach to diagnose carotid artery stenosis using long-circulating bovine serum albumin (BSA)-Gd2O3 nanoparticles (NPs). The BSA-Gd2O3 NPs synthesized by a simple biomineralization approach exhibit admirable monodispersity, uniform size, favorable aqueous solubility, good biocompatibility, and high relaxivity (14.86 mM-1 s-1 in water, 6.41 mM-1 s-1 in plasma). In vivo MRA imaging shows that outstanding vascular enhancement of BSA-Gd2O3 NPs (0.05 mmol Gd/kg, half the dose in the clinic) can be maintained for at least 2 h, much longer than Gd-DTPA. Vessels as small as 0.3 mm can be clearly observed in MRA images with high resolution. In a rat carotid artery stenosis model, the BSA-Gd2O3 NPs-based MRA enables the precise diagnosis of the severity and location and the therapeutic effect following the surgery of carotid artery stenosis, which provides a method for the theranostics of vascular diseases.

Agglomerated serum albumin adsorbed protocatechuic acid coated superparamagnetic iron oxide nanoparticles as a theranostic agent

Iron oxide nanoparticles have been one of the most widely used nanomaterials in biomedical applications. However, the incomplete understanding of the toxicity mechanisms limits their use in diagnosis and treatment processes. Many parameters are associated with their toxicity such as size, surface modification, solubility, concentration and immunogenicity. Further research needs to be done to address toxicity-related concerns and to increase its effectiveness in various applications. Herein, colloidally stable nanoparticles were prepared by coating magnetic iron oxide nanoparticles (MIONPs) with protocatechuic acid (PCA) which served as a stabilizer and a linkage for a further functional layer. A new perfusion agent with magnetic imaging capability was produced by the adsorption of biocompatible passivating agent macro-aggregated albumin (MAA) on the PCA-coated MIONPs. PCA-coated MIONPs were investigated using infrared spectroscopy, thermogravimetric analysis and dynamic light scattering while adsorption of MAA was analysed by transmission electron microscopy, Fourier-transform infrared spectroscopy and x-ray diffraction methods. Magnetic measurements of samples indicated that all samples showed superparamagnetic behaviour. Cytotoxicity results revealed that the adsorption of MAA onto PCA-coated MIONPs provided an advantage by diminishing their toxicity against the L929 mouse fibroblast cell line compared to bare Fe₃O₄.

Native Study of the Behaviour of Magnetite Nanoparticles for Hyperthermia Treatment during the Initial Moments of Intravenous Administration

Magnetic nanoparticles (MNPs) present outstanding properties making them suitable as therapeutic agents for hyperthermia treatments. Since the main safety concerns of MNPs are represented by their inherent instability in a biological medium, strategies to both achieve long-term stability and monitor hazardous MNP degradation are needed. We combined a dynamic approach relying on flow field flow fractionation (FFF)-multidetection with conventional techniques to explore frame-by-frame changes of MNPs injected in simulated biological medium, hypothesize the interaction mechanism they are subject to when surrounded by a saline, protein-rich environment, and understand their behaviour at the most critical point of intravenous administration. In the first moments of MNPs administration in the patient, MNPs change their surrounding from a favorable to an unfavorable medium, i.e., a complex biological fluid such as blood; the particles evolve from a synthetic identity to a biological identity, a transition that needs to be carefully monitored. The dynamic approach presented herein represents an optimal alternative to conventional batch techniques that can monitor only size, shape, surface charge, and aggregation phenomena as an averaged information, given that they cannot resolve different populations present in the sample and cannot give accurate information about the evolution or temporary instability of MNPs. The designed FFF method equipped with a multidetection system enabled the separation of the particle populations providing selective information on their morphological evolution and on nanoparticle-proteins interaction in the very first steps of infusion. Results showed that in a dynamic biological setting and following interaction with serum albumin, PP-MNPs retain their colloidal properties, supporting their safety profile for intravenous administration.

Albumin-Functionalized Iron Oxide Nanoparticles for Theranostics: Engineering and Long-Term In Situ Imaging

Magnetic nanosystems (MNSs) consisting of magnetic iron oxide nanoparticles (IONPs) coated by human serum albumin (HSA), commonly used as a component of hybrid nanosystems for theranostics, were engineered and characterized. The HSA coating was obtained by means of adsorption and free radical modification of the protein molecules on the surface of IONPs exhibiting peroxidase-like activity. The generation of hydroxyl radicals in the reaction of IONPs with hydrogen peroxide was proven by the spin trap technique. The methods of dynamic light scattering (DLS) and electron magnetic resonance (EMR) were applied to confirm the stability of the coatings formed on the surface of the IONPs. The synthesized MNSs (d ~35 nm by DLS) were intraarterially administered in tumors implanted to rats in the dose range from 20 to 60 μg per animal and studied in vivo as a contrasting agent for computed tomography. The long-term (within 14 days of the experiment) presence of the MNSs in the tumor vascular bed was detected without immediate or delayed adverse reactions and significant systemic toxic effects during the observation period. The peroxidase-like activity of MNSs was proven by the colorimetric test with o-phenylenediamine (OPD) as a substrate. The potential of the synthesized MNSs to be used for theranostics, particularly, in oncology, was discussed.

Photothermal effects of CuS-BSA nanoparticles on H22 hepatoma-bearing mice

The objective of this study was to evaluate the in vivo application and photothermal ablation effects and mechanism of copper sulfide nanoparticles (CuS NPs) in hepatocellular carcinoma (HCC). Sheet-like CuS-BSA NPs with a particle size of 30 nm were synthesized using bovine serum albumin (BSA) as a biological modifier, and were physically characterized. To provide a reference range for the biosafety dose of CuS-BSA NPs, 36 male Kunming mice were randomly assigned into six groups. Different one-time doses of CuS-BSA NPs were injected via tail vein injection, and the potential damages of liver, kidney and spleen were observed 14 days later. To evaluate the in vivo photothermal effect of CuS-BSA NPs, 48 male Kunming mice were used to establish the H22 hepatoma-bearing mouse model and were randomly assigned into six groups. CuS-BSA NPs (600 μg/kg) were injected via tail vein or intratumoral injection. Irradiations were performed 30 min after injection, with a 980 nm near-infrared laser (2.0 W/cm²) for 10 min once a week for 3 weeks. The results indicated that the CuS-BSA NPs had good dispersibility in three different solvents and had a strong absorption peak at 980 nm. The heating curves demonstrated that the photothermal effects of CuS-BSA NPs aqueous solution exhibited concentration dependence and power density dependence. In the in vivo experiment, when the doses of CuS-BSA NPs were in the range of 1800–7,200 μg/kg, the thymus index and spleen index of mice were not significantly different from those of the control group, and the structures of liver, kidney and spleen were intact without remarkable pathological changes. A lower dose of CuS-BSA NPs (600 μg/kg) could effectively inhibit tumor growth in H22 hepatoma-bearing mice at 980 nm NIR. Moreover, under the near-infrared laser irradiation, both in the tail vein injection group and the intratumoral injection group, a large area of necrosis in the tumor tissue, as well as the up-regulation of apoptotic proteins including cleaved caspase-3 and cleaved caspase-9 were observed. CuS-BSA NPs are promising photothermal agents in the photothermal therapy of cancer.

A review on recent advances in the applications of composite Fe3O4 magnetic nanoparticles in the food industry

Fe3O4 magnetic nanoparticles (MNPs) have attracted tremendous attention due to their superparamagnetic properties, large specific surface area, high biocompatibility, non-toxicity, large-scale production, and recyclability. More importantly, numerous hydroxyl groups (-OH) on the surface of Fe3O4 MNPs can provide coupling sites for various modifiers, forming versatile nanocomposites for applications in the energy, biomedicine, and environmental fields. With the development of science and technology, the potential of nanotechnology in the food industry has also gradually become prominent. However, the application of composite Fe3O4 MNPs in the food industry has not been systematically summarized. Herein, this article reviews composite Fe3O4 MNPs, including their properties, modifications, and physical functions, as well as their applications in the entire food industry from production to processing, storage, and detection. This review lays a solid foundation for promoting food innovation and improving food quality and safety.

Serum Albumin for Magnetic Nanoparticles Coating

Magnetic nanoparticles (MNPs) have great potential in biochemistry and medical science. In particular, iron oxide nanoparticles have demonstrated a promising effect in various biomedical applications due to their high magnetic properties, large surface area, stability, and easy functionalization. However, colloidal stability, biocompatibility, and potential toxicity of MNPs in physiological environments are crucial for their in vivo application. In this context, many research articles focused on the possible procedures for MNPs coating to improve their physic-chemical and biological properties. This review highlights one viable fabrication strategy of biocompatible iron oxide nanoparticles using human serum albumin (HSA). HSA is mainly a transport protein with many functions in various fundamental processes. As it is one of the most abundant plasma proteins, not a single drug in the blood passes without its strength test. It influences the stability, pharmacokinetics, and biodistribution of different drug-delivery systems by binding or forming its protein corona on the surface. The development of albumin-based drug carriers is gaining increasing importance in the targeted delivery of cancer therapy. Considering this, HSA is a highly potential candidate for nanoparticles coating and theranostics area and can provide biocompatibility, prolonged blood circulation, and possibly resolve the drug-resistance cancer problem.

Metallic Nanoparticle-Mediated Immune Cell Regulation and Advanced Cancer Immunotherapy

Cancer immunotherapy strategies leveraging the body's own immune system against cancer cells have gained significant attention due to their remarkable therapeutic efficacy. Several immune therapies have been approved for clinical use while expanding the modalities of cancer therapy. However, they are still not effective in a broad range of cancer patients because of the typical immunosuppressive microenvironment and limited antitumor immunity achieved with the current treatment. Novel approaches, such as nanoparticle-mediated cancer immunotherapies, are being developed to overcome these challenges. Various types of nanoparticles, including liposomal, polymeric, and metallic nanoparticles, are reported for the development of effective cancer therapeutics. Metallic nanoparticles (MNPs) are one of the promising candidates for anticancer therapy due to their unique theranostic properties and are thus explored as both imaging and therapeutic agents. In addition, MNPs offer a dense surface functionalization to target tumor tissue and deliver genetic, therapeutic, and immunomodulatory agents. Furthermore, MNPs interact with the tumor microenvironment (TME) and regulate the levels of tumor hypoxia, glutathione (GSH), and reactive oxygen species (ROS) for remodulation of TME for successful therapy. In this review, we discuss the role of nanoparticles in tumor microenvironment modulation and anticancer therapy. In particular, we evaluated the response of MNP-mediated immune cells, such as dendritic cells, macrophages, T cells and NK cells, against tumor cells and analyzed the role of MNP-based cancer therapies in regulating the immunosuppressive environment.

New Prospects in Neutering Male Animals Using Magnetic Nanoparticle Hyperthermia

Controlling populations of free-roaming dogs and cats poses a huge challenge worldwide. Non-surgical neutering strategies for male animals have been long pursued, but the implementation of the procedures developed has remained limited to date. As submitting the testes to high temperatures impairs spermatogenesis, the present study investigated localized application of magnetic nanoparticle hyperthermia (MNH) to the testicles as a potential non-surgical sterilization method for animals. An intratesticular injection of a magnetic fluid composed of manganese-ferrite nanoparticles functionalized with citrate was administered followed by testicle exposure to an alternate magnetic field to generate localized heat. Testicular MNH was highly effective, causing progressive seminiferous tubule degeneration followed by substitution of the parenchyma with stromal tissue and gonadal atrophy, suggesting an irreversible process with few side effects to general animal health.

Synthesis and characterization of hybrid nanocarrier layered double hydroxide grafted by polyethylene glycol and gemcitabine

For the past few years, organic-inorganic hybrid nanocarriers have been widely explored for effective drug delivery and preferable disease treatments. In this article, hydrothermal method was utilized to prepare fine dispersed layered double hydroxide (Mg-Al LDH) suspension. Polyethylene glycol (PEG) was grafted on the surface of LDH lamella in order to improve the dispersibility of LDH. Besides, the anti-cancer drug gemcitabine was grafted on the surface of LDH lamellas through chemical grafting. Hence a novel new type of organic-inorganic hybrid drug delivery system LDH-mPEG-Gemcitabine was obtained. In addition, the siRNA was intercalated into the LDH interlamination by ion exchange method to realize drug and gene co-delivery. The loading capacity of LDH and LDH-mPEG-Gemcitabine was evaluated by agarose gel electrophoresis. The characterization by laser particle size analyzer, TEM, FT-IR, XRD, in vitro cell viability and in vitro drug release demonstrated that LDH-mPEG-Gemcitabine possessed fine dispersibility, uniform morphology and particle size, fine biocompatibility, ideal drug loading and releasing capacity and held great potential to be used as a desired co-delivery system for drug and gene.

Emerging Applications of Nanotechnology in Healthcare Systems: Grand Challenges and Perspectives

Healthcare, as a basic human right, has often become the focus of the development of innovative technologies. Technological progress has significantly contributed to the provision of high-quality, on-time, acceptable, and affordable healthcare. Advancements in nanoscience have led to the emergence of a new generation of nanostructures. Each of them has a unique set of properties that account for their astonishing applications. Since its inception, nanotechnology has continuously affected healthcare and has exerted a tremendous influence on its transformation, contributing to better outcomes. In the last two decades, the world has seen nanotechnology taking steps towards its omnipresence and the process has been accelerated by extensive research in various healthcare sectors. The inclusion of nanotechnology and its allied nanocarriers/nanosystems in medicine is known as nanomedicine, a field that has brought about numerous benefits in disease prevention, diagnosis, and treatment. Various nanosystems have been found to be better candidates for theranostic purposes, in contrast to conventional ones. This review paper will shed light on medically significant nanosystems, as well as their applications and limitations in areas such as gene therapy, targeted drug delivery, and in the treatment of cancer and various genetic diseases. Although nanotechnology holds immense potential, it is yet to be exploited. More efforts need to be directed to overcome these limitations and make full use of its potential in order to revolutionize the healthcare sector in near future.

A Review of pH-Responsive Organic-Inorganic Hybrid Nanoparticles for RNAi-Based Therapeutics

RNA interference (RNAi) shows great potential in the treatment of varying cancer and genetic disorders. The lack of safe and effective delivery methods is an ongoing challenge to realize the full potential of RNAi-based therapeutics. pH-responsive hybrid nanoparticle is a promising non-virus platform for small interfering RNA (siRNA) delivery with unique properties including the robust response to the acidic microenvironment and the capability of theranostic and combined therapeutics. The mechanism of RNAi and the delivery barriers for RNAi-based therapeutics are first discussed. Then, the general patterns of pH-response and the typical construction of hybrid nanoparticles are demonstrated. The recent advances in pH-responsive organic-inorganic hybrid nanoparticles for siRNA delivery are highlighted, in particular, how pH-response of ionizable groups, acid-labile bonds, and decomposition of inorganic components affect the physicochemical properties of hybrid nanoparticles and benefit the cellular uptake and intracellular trafficking of siRNA payloads are discussed. At last, the remaining problems and the prospects for pH-responsive hybrid nanoparticles for siRNA delivery are analyzed.

Fundamentals to Apply Magnetic Nanoparticles for Hyperthermia Therapy

The activation of magnetic nanoparticles in hyperthermia treatment by an external alternating magnetic field is a promising technique for targeted cancer therapy. The external alternating magnetic field generates heat in the tumor area, which is utilized to kill cancerous cells. Depending on the tumor type and site to be targeted, various types of magnetic nanoparticles, with variable coating materials of different shape and surface charge, have been developed. The tunable physical and chemical properties of magnetic nanoparticles enhance their heating efficiency. Moreover, heating efficiency is directly related with the product values of the applied magnetic field and frequency. Protein corona formation is another important parameter affecting the heating efficiency of MNPs in magnetic hyperthermia. This review provides the basics of magnetic hyperthermia, mechanisms of heat losses, thermal doses for hyperthermia therapy, and strategies to improve heating efficiency. The purpose of this review is to build a bridge between the synthesis/coating of magnetic nanoparticles and their practical application in magnetic hyperthermia.

Green synthesis, antimicrobial, antibiofilm and antitumor activities of superparamagnetic γ-Fe2O3 NPs and their molecular docking study with cell wall mannoproteins and peptidoglycan

Fatty acids-assisted superparamagnetic maghemite (γ-Fe₂O₃) NPs was biologically synthesized using extract of polyherbal drug Liv52 (L52E). The NPs were characterized by UV-vis spectroscopy, FT-IR, SEM, TEM, EDX, XRD and VSM. The major biological molecules present in L52E analysed by GC-MS were saturated fatty acids (palmitic acid 21.95%; stearic acid 13.99%; myristic acid 1.14%), monounsaturated fatty acid (oleic acid 18.43%), polyunsaturated fatty acid (linoleic acid 20.45%), and aromatic phenol (cardanol monoene 11.92%) that could imply in bio-fabrication and stabilization of γ-Fe₂O₃ NPs. The FT-IR spectra revealed involvement of carboxylic group of fatty acids, amide group of proteins and hydroxyl group of phenolic compounds that acts as reducing and capping agents. The synthesized NPs were used to investigate their antimicrobial, antibiofilm activity against P. aeruginosa, MRSA and C. albicans and anticancer activity on colon cancer cells (HCT-116) for biomedical applications. Further, molecular docking study was performed to explore the interaction of Fe₂O₃ NPs with major cell wall components i.e., peptidoglycan and mannoproteins. The docking studies revealed that Fe₂O₃ interacted efficiently with peptidoglycan and mannoproteins and Fe₂O₃ get accommodated into catalytic cleft of mannoprotein. Due to magnetic property, the biological activity of γ-Fe₂O₃ can be further enhanced by applying external magnetic field alone or in amalgamation with other therapeutics drugs.

Intra-Arterial Infusion of Magnetic Nanoparticle-Based Theragnostic Agent to Treat Colorectal Cancer Liver Implants in Rats

INTRODUCTION

Nowadays, surgical excision remains the gold standard to treat liver metastases of colorectal cancer (CRCLM). However, as more than 50% of patients are not eligible for surgery, other alternatives such as percutaneous or intravascular interventional therapies (thermal ablation, chemoembolization, or radioembolization), are quite relevant. Recently, the use of magnetic nanoparticles (MNPs) has been suggested as an adjuvant for these therapies, as they could increase their necrotising effect on the tumour while reducing doses and exposure times of thermal therapies. To investigate the potential curative effect of these compounds, animal models are needed, both for the development of experimental interventional procedures and for MNPs toxicity and distribution assessment. Herein, we describe both an experimental infusion procedure in CRCLM-bearing rats and analytical and histological methods to evaluate MNPs deposits in the tissue.

METHODS

Eighteen male WAG/RijHsd rats were subjected to intrahepatic injection of 250,000 colorectal cancer cells. Twenty-eight days later, half of the tumour-positive animals (n = 6) were administered with MNPs while the other half (n = 6) did not receive any injection and were used as control. Under microscope magnification, the splenic artery was carefully and completely dissected, and a catheter was inserted through the splenic artery to the common hepatic artery where 1 mL MNPs suspension was administered in 5 min; then STIR, DP*, and T2 MRI sequences were obtained (and signal intensity measured) and both tumour and liver tissue samples were collected for elemental and histological analyses.

CONCLUSION

Our method for selective administration of MNPs is reproducible and well-tolerated and it fairly mimics the approach used in clinical practice when intravascular interventional therapies are applied.

Immobilization of protein on Fe3O4 nanoparticles for magnetic hyperthermia application

We report a facile approach for the preparation of protein conjugated glutaric acid functionalized Fe₃O₄ magnetic nanoparticles (Pro-Glu-MNPs), having improved colloidal stability and heating efficacy. The Pro-Glu-MNPs were prepared by covalent conjugation of BSA protein onto the surface of glutaric acid functionalized Fe₃O₄ magnetic nanoparticles (Glu-MNPs) obtained through thermal decomposition. XRD and TEM analyses confirmed the formation of crystalline Fe₃O₄ nanoparticles of average size ~5 nm, whereas the conjugation of BSA protein to them was evident from XPS, FTIR, TGA, DLS and zeta-potential measurements. These Pro-Glu-MNPs showed good colloidal stability in different media (water, phosphate buffer saline, cell culture medium) and exhibited room temperature superparamagnetism with good magnetic field responsivity towards the external magnet. The induction heating studies revealed that the heating efficacy of these Pro-Glu-MNPs was strongly reliant on the particle concentration and their stabilizing media. In addition, they showed enhanced heating efficacy over Glu-MNPs as surface passivation by protein offers colloidal stability to them as well as prevents their aggregation under AC magnetic field. Further, Pro-Glu-MNPs are biocompatible towards normal cells and showed substantial cellular internalization in cancerous cells, suggesting their potential application in hyperthermia therapy.

Glutamic acid-coated Fe3O4 nanoparticles for tumor-targeted imaging and therapeutics

We have developed surface functionalised Fe₃O₄ magnetic nanoparticles (MNPs) based system that can be used for tumor-targeted multimodal therapies and MR imaging. Biocompatible, non-essential amino acid (glutamic acid) was introduced onto the surface of Fe₃O₄ MNPs to provide functional sites for binding of chemotherapeutic drugs. These glutamic acid-coated Fe₃O₄ MNPs (GAMNPs) exhibit good water-dispersibility, magnetic responsivity and pH dependent charge conversal feature. The magnetic core as well as organic shell of GAMNPs was characterized by XRD, TEM, DLS, FTIR, PPMS and UV-visible spectroscopy and zeta-potential analyzer etc. The broad spectrum anticancer drugs, doxorubicin hydrochloride (DOX) and methotrexate (MTX) were electrostatically and covalently conjugated to the surface of GAMNPs, respectively for combination chemotherapy. These dual drugs loaded system (DOX-MTX-GAMNPs) shows pH dependent release behaviour of both the drugs and enhanced toxicity towards breast cancer cell line (MCF-7) as compared to their individual treatment. Fluorescence microscopy and flow cytometric analyses confirmed the successful uptake of drug loaded system into MCF-7 cell lines. Further MTX being analogue of folic acid, its co-delivery with DOX would help in internalization of both the drugs into MCF-7 cells. These GAMNPs also show good heating efficiency under AC magnetic field (Intrinsic loss power, ILP = 0.95 and 0.73 and 0.48 nHm²/Kg at Fe concentration of 0.5, 1 and 2 mg/ml, respectively) and transverse relaxivity (r₂ = 152 mM^-1 s^-1) indicating their potential capability for hyperthermia therapy and MRI tracking. Furthermore, it has been observed that the combination of chemotherapeutic drugs and hyperthermia leads to an enhancement of cytotoxicity in MCF-7 cells.

Antibacterial activity of iron oxide, iron nitride, and tobramycin conjugated nanoparticles against Pseudomonas aeruginosa biofilms

BACKGROUND

Novel methods are necessary to reduce morbidity and mortality of patients suffering from infections with Pseudomonas aeruginosa. Being the most common infectious species of the Pseudomonas genus, P. aeruginosa is the primary Gram-negative etiology responsible for nosocomial infections. Due to the ubiquity and high adaptability of this species, an effective universal treatment method for P. aeruginosa infection still eludes investigators, despite the extensive research in this area.

RESULTS

We report bacterial inhibition by iron-oxide (nominally magnetite) nanoparticles (NPs) alone, having a mean hydrodynamic diameter of ~ 16 nm, as well as alginate-capped iron-oxide NPs. Alginate capping increased the average hydrodynamic diameter to ~ 230 nm. We also investigated alginate-capped iron-oxide NP-drug conjugates, with a practically unchanged hydrodynamic diameter of ~ 232 nm. Susceptibility and minimum inhibitory concentration (MIC) of the NPs, NP-tobramycin conjugates, and tobramycin alone were determined in the PAO1 bacterial colonies. Investigations into susceptibility using the disk diffusion method were done after 3 days of biofilm growth and after 60 days of growth. MIC of all compounds of interest was determined after 60-days of growth, to ensure thorough establishment of biofilm colonies.

CONCLUSIONS

Positive inhibition is reported for uncapped and alginate-capped iron-oxide NPs, and the corresponding MICs are presented. We report zero susceptibility to iron-oxide NPs capped with polyethylene glycol, suggesting that the capping agent plays a major role in enabling bactericidal ability in of the nanocomposite. Our findings suggest that the alginate-coated nanocomposites investigated in this study have the potential to overcome the bacterial biofilm barrier. Magnetic field application increases the action, likely via enhanced diffusion of the iron-oxide NPs and NP-drug conjugates through mucin and alginate barriers, which are characteristic of cystic-fibrosis respiratory infections. We demonstrate that iron-oxide NPs coated with alginate, as well as alginate-coated magnetite-tobramycin conjugates inhibit P. aeruginosa growth and biofilm formation in established colonies. We have also determined that susceptibility to tobramycin decreases for longer culture times. However, susceptibility to the iron-oxide NP compounds did not demonstrate any comparable decrease with increasing culture time. These findings imply that iron-oxide NPs are promising lower-cost alternatives to silver NPs in antibacterial coatings, solutions, and drugs, as well as other applications in which microbial abolition or infestation prevention is sought.

Effects of multiple injections on the efficacy and cytotoxicity of folate-targeted magnetite nanoparticles as theranostic agents for MRI detection and magnetic hyperthermia therapy of tumor cells

Folate-targeted iron oxide nanoparticles (FA@Fe3O4 NPs) were prepared by a one-pot hydrothermal method and then used as cancer theranostic agents by combining magnetic resonance imaging (MRI) and magnetic hyperthermia therapy (MHT). Crystal structure, morphology, magnetic properties, surface functional group, and heating efficacy of the synthesized nanoparticles were characterized by XRD, TEM, VSM, FTIR, and hyperthermia analyses. The results indicated that the crystal structure, magnetic properties, and heating efficacy of the magnetite nanoparticles were improved by hydrothermal treatment. Toxicity of the prepared NPs was assessed in vitro and in vivo on the mammary cells and BALB/c mice, respectively. The results of the in vitro toxicity analysis showed that the FA@Fe3O4 NPs are relatively safe even at high concentrations of the NPs up to 1000 µg mL-1. Also, the targetability of the FA@Fe3O4 NPs for the detection of folate over-expressed cancer cells was evaluated in an animal model of breast tumor using MRI analysis. It was observed that T2-weighted magnetic resonance signal intensity was decreased with the three-time injection of the FA@Fe3O4 NPs with 24 h interval at a safe dose (50 mg kg-1), indicating the accumulation and retention of the NPs within the tumor tissues. Moreover, the therapeutic efficacy of the MHT using the FA@Fe3O4 NPs was evaluated in vivo in breast tumor-bearing mice. Hyperthermia treatment was carried out under a safe alternating magnetic field permissible for magnetic hyperthermia treatment (f = 150 kHz, H = 12.5 mT). The therapeutic effects of the MHT were evaluated by monitoring the tumor volume during the treatment period. The results showed that the mice in the control group experienced an almost 3.5-fold increase in the tumor volume during 15 days, while, the mice in the MHT group had a mild increase in the tumor volume (1.8-fold) within the same period (P < 0.05). These outcomes give promise that FA@Fe3O4 NPs can be used as theranostic agents for the MRI and MHT applications.

Study of interactions between carboxylated core shell magnetic nanoparticles and polymyxin B by capillary electrophoresis with inductively coupled plasma mass spectrometry

In this work, interactions of carboxylated core shell magnetic nanoparticles with polymyxin B sulfate were studied by connecting capillary electrophoresis with inductively coupled plasma mass spectrometry. The interaction was probed by affinity mode of capillary electrophoresis with 25 mM phosphate buffer at physiological pH. ⁵⁴Fe, ⁵⁶Fe, ⁵⁷Fe, ³⁴S, and ¹²C isotopes were used to monitor the migration of an electroosmotic flow marker and the interaction of the nanoparticles with polymyxin B. The analysis of interaction data showed two distinct interaction regions, one with low polymyxin B concentration, the second with high polymyxin B concentration. These regions differed in the strength of the interaction, 1.49 × 10⁷ M^-1 and 1.60 × 10⁴ M^-1, and in the stoichiometry of 0.7 and 3.5, respectively. These differences can be explained by the decrease of electrostatic repulsion between nanoparticles caused by polymyxin B. This is also in agreement with the nanoparticles peak shapes: sharp for low polymyxin B concentrations and broad for high polymyxin B concentrations.

Highly Tough, Biocompatible, and Magneto-Responsive Fe3O4/Laponite/PDMAAm Nanocomposite Hydrogels

Magneto-responsive hydrogels (MRHs) have attracted considerable attention in various applications owing to their smart response to an externally applied magnetic field. However, their practical uses in biomedical fields are limited by their weak mechanical properties and possible toxicity to the human body. In this study, tough, biocompatible, and magneto-responsive nanocomposite hydrogels (MR_NCHs) were developed by the in-situ free-radical polymerization of N, N-dimethylacrylamide (DMAAm) and laponite and Fe3O4 nanoparticles. The effects of the concentrations of DMAAm, water, and laponite and Fe3O4 nanoparticles in the pre-gel solutions or mixtures on the viscoelastic and mechanical properties of the corresponding hydrogels were examined by performing rheological and tensile tests, through which the mixture composition producing the best MR_NCH system was optimized. The effects were also explained by the possible network structures of the MR_NCHs. Moreover, the morphology, chemical structure, and thermal and mechanical properties of the MR_NCHs were analyzed, while comparing with those of the poly(DMAAm) (PDMAAm) hydrogels and laponite/PDMAAm NCHs. The obtained optimal MR_NCH exhibited noticeable magnetorheological (MR) behavior, excellent mechanical properties, and good biocompatibility. This study demonstrates how to optimize the best Fe3O4/laponite/PDMAAm MR_NCH system and its potential as a soft actuator for the pharmaceutical and biomedical applications.

Magnetic Hyperthermia in Y79 Retinoblastoma and ARPE-19 Retinal Epithelial Cells: Tumor Selective Apoptotic Activity of Iron Oxide Nanoparticle

Purpose

To evaluate selective apoptosis of Y79 retinoblastoma versus ARPE-19 retinal pigment epithelial cells by using different doses of dextran-coated iron oxide nanoparticles (DCIONs) in a magnetic hyperthermia paradigm.

Methods

Y79 and ARPE-19 cells were exposed to different concentrations of DCIONs, namely, 0.25, 0.5, 0.75, and 1 mg/ml. After 2 hours of incubation, cells were exposed to a magnetic field with a frequency of 250 kHz and an amplitude of 4 kA/m for 30 minutes to raise the cellular temperature between 42 and 46°C. Y79 and ARPE-19 cells incubated with DCION without magnetic field exposure were used as controls. Cell viability and apoptosis were assessed at 4, 24, and 72 hours after hyperthermia treatment.

Results

At 4 hours following magnetic hyperthermia, cell death for Y79 cells was 1%, 8%, 17%, and 17% for 0.25, 0.5, 0.75 and 1 mg/ml of DCION, respectively. Cell death increased to 47%, 59%, 70%, and 75% at 24 hours and 16%, 45%, 50%, and 56% at 72 hours for 0.25, 0.5, 0.75, and 1 mg/ml of DCIONs, respectively. Magnetic hyperthermia did not have any significant toxic effects on ARPE-19 cells at all DCION concentrations, and minimal baseline cytotoxicity of DCIONs on Y79 and ARPE-19 cells was observed without magnetic field activation. Gene expression profiling showed that genes involved in FAS and tumor necrosis factor alpha signaling pathways were activated in Y79 cells following hyperthermia. Caspase 3/7 activity in Y79 cells increased following treatment, consistent with the activation of caspase-mediated apoptosis and loss of cell viability by magnetic hyperthermia.

Conclusion

Magnetic hyperthermia using DCIONs selectively kills Y79 cells at 0.5 mg/ml or higher concentrations via the activation of apoptotic pathways.

Translational Relevance

Magnetic hyperthermia using DCIONs might play a role in targeted management of retinoblastoma.

Determination of conjugated protein on nanoparticles by an adaptation of the Coomassie blue dye method

A new accurate spectrophotometric method for protein determination on nanoparticles is described. The method is based on the Coomassie blue dye that binds to the basic and aromatic amino acid residues of proteins, especially arginine and lysine. A known amount of reagent dye was mixed with a variety of protein-loaded nanoparticles. Thereafter the unconjugated reagent was mixed with excess protein (bovine serum albumin) and titrated. In this method, the reacted dye on the protein coating of nanoparticle is directly determined, in opposite to the conventional method, in which the conjugated protein is determined as the difference between the non-conjugated protein found in the supernatant after centrifugation, and the total amount of protein originally used. This method is able to measure amounts of coated protein lower than 1 ppm.

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Simple and accurate method especially adapted for protein-coated nanoparticles.

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The amino acid residues of protein in the nanoparticle surface react with Coomassie brilliant blue dye.

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The unreacted dye is titrated with an excess of a standard protein.

Tumor-Specific Expansion of Oxidative Stress by Glutathione Depletion and Use of a Fenton Nanoagent for Enhanced Chemodynamic Therapy

Amplifying intracellular oxidative stress effectively destroys cancer cells. In addition, iron-mediated Fenton reaction converts endogenous H₂O₂ to produce hypertoxic hydroxyl radical (^•OH), resulting in irreversible oxidative damage to combat tumor cells. This method is known as chemodynamic therapy (CDT). Overexpressed glutathione (GSH) in tumor cells efficiently scavenges ^•OH, significantly reducing the curative effects of CDT. To overcome this challenge and enhance intracellular oxidative stress, iron oxide nanocarriers loaded with β-lapachone (Lapa) drugs (Fe₃O₄-HSA@Lapa) were constructed and had both Fenton-like agents and GSH depletion properties to amplify intracellular oxidative stress. Release of Lapa selectively increases tumor site-specific generation of H₂O₂ via NAD(P)H: quinone oxidoreductase 1 (NQO1) catalysis. Subsequently, the iron ions released from the ionization of Fe₃O₄ in the acidic environment selectively convert H₂O₂ into highly toxic ^•OH by Fenton reaction, dramatically improving CDT with minimal systemic toxicity due to low NQO1 expression in normal tissues. Meanwhile, released Lapa consumes GSH in the tumor, amplifying oxidative stress and enhancing the efficacy of CDT. Designed Fe₃O₄-HSA@Lapa nanoparticles (NPs) exhibit perfect targeting capability, prolonged blood circulation, and increased tumor accumulation. Furthermore, Fe₃O₄-HSA@Lapa NPs effectively enhance the inhibition of tumor growth and reduce the side effects of anticancer drugs. This work establishes a remarkably enhanced tumor-selective CDT against NQO1-overexpressing tumors by significantly inducing intratumoral oxidative stress with minimal side effects.

Magnetic hyperthermia of breast cancer cells and MRI relaxometry with dendrimer-coated iron-oxide nanoparticles

BACKGROUND

Recently, some studies have focused on dendrimer nanopolymers as a magnetic resonance imaging (MRI) contrast agent or a vehicle for gene and drug delivery. Considering the suitable properties of these materials, they are appropriate candidates for coating iron-oxide nanoparticles which are applied in magnetic hyperthermia. To the best of our knowledge, the novelty of this study is the investigation of fourth-generation dendrimer-coated iron-oxide nanoparticles (G4@IONPs) in magnetic hyperthermia and MRI.

METHODS

IONPs were synthesized via co-precipitation and coated with the fourth generation (G4) of polyamidoamine dendrimer. The cytotoxicity of G4@IONPs with different concentrations was assessed in a human breast cancer cell line (MCF7) and human fibroblast cell line (HDF1). Hemolysis and stability of G4@IONPs were investigated, and in addition, the interaction of these particles with MCF7 cells was assessed by Prussian blue staining. Heat generation and specific absorption rate (SAR) were calculated from measurement and simulation results at 200 and 300 kHz. MCF7 and HDF1 cells were incubated with G4@IONPs for 2 h and then put into the magnetic coil for 120 min. Relaxometry experiments were performed with different concentrations of G4@IONPs with T1- and T2-weighted MR images.

RESULTS

The TEM results showed that G4@IONPs were 10 ± 4 nm. The in vitro toxicity assessments showed that synthesized nanoparticles had low toxicity. The viability of MCF7 cells incubated with G4@IONPs decreased significantly after magnetic hyperthermia. In addition, MR imaging revealed that G4@IONPs improved transverse relaxivity (r2) significantly.

CONCLUSIONS

Our results encouraged the future application of G4@IONPs in magnetic hyperthermia and MR imaging.

Local hyperthermia in head and neck cancer: mechanism, application and advance

Local hyperthermia (HT), particularly in conjunction with surgery, radiotherapy and chemotherapy was useful for the treatment of human malignant tumors including head and neck cancer. However, at present it suffered from many limitations such as thermal dose control, target treatment regions and discrimination between healthy and cancer cells. Recent developments in nanotechnology have introduced novel and smart therapeutic nanomaterials to local HT of head and neck cancer that basically take advantage of various targeting approaches. The aim of this paper is to give a brief review of the mechanism, methods and clinical applications of local HT in head and neck cancer, mainly focusing on photothermal therapy (PTT) and nanoparticle-based hyperthermia.

Using X-rays in photodynamic therapy: an overview

Photodynamic therapy is a therapeutic option to treat cancer and other diseases.

RGD-QD-MoS2 nanosheets for targeted fluorescent imaging and photothermal therapy of cancer

The fast-developing field of nanotechnology provides unprecedented opportunities for the increasing demands of biomedicine, especially for cancer diagnostics and treatment. Here, novel multifunctional zero-dimensional-two-dimensional (0D-2D) RGD-QD-MoS₂ nanosheets (NSs) with excellent fluorescence, photothermal conversion, and cancer-targeting properties were successfully prepared by functionalizing single-layer MoS₂ NSs with fluorescent quantum dots (QDs) and arginine-glycine-aspartic (RGD) containing peptides. By using RGD-QD-MoS₂ NSs as a multifunctional theranostic agent, targeted fluorescent imaging and photothermal therapy (PTT) of human cervical carcinoma (HeLa) cells were achieved. Moreover, HeLa tumors in mouse models can be fluorescently imaged and completely eradicated by photothermal irradiation using a low power NIR laser, due to the effective accumulation of RGD-QD-MoS₂ NSs at the tumor sites through the RGD-integrin targeting and the enhanced penetration and retention (EPR) effect. Without exhibiting any appreciable toxicity to treated cells or animals, RGD-QD-MoS₂ NSs have been demonstrated as promising multifunctional theranostic agents for cancer imaging and therapy.

An experimental and computational framework for engineering multifunctional nanoparticles: designing selective anticancer therapies

A key challenge in the treatment of cancer with nanomedicine is to engineer and select nanoparticle formulations that lead to the desired selectivity between tumorigenic and non-tumorigenic cells. To this aim, novel designed nanomaterials, deep biochemical understanding of the mechanisms of interaction between nanomaterials and cells, and computational models are emerging as very useful tools to guide the design of efficient and selective nanotherapies. This works shows, using a combination of detailed experimental approaches and simulations, that the specific targeting of cancer cells in comparison to non-tumorigenic cells can be achieved through the custom design of multivalent nanoparticles. A theoretical model that provides simple yet quantitative predictions to tune the nanoparticles targeting and cytotoxic properties by their degree of functionalization is developed. As a case study, a system that included a targeting agent and a drug and is amenable to controlled experimental manipulation and theoretical analysis is used. This study shows how at defined functionalization levels multivalent nanoparticles can selectively kill tumor cells, while barely affecting non-tumorigenic cells. This work opens a way to the rational design of multifunctionalized nanoparticles with defined targeting and cytotoxic properties for practical applications.

Synthesis and characterization of magnetite nanoparticles having different cover layer and investigation of cover layer effect on the adsorption of lysozyme and bovine serum albumin

In this study, differently coated superparamagnetic Fe₃O₄ (magnetite) nanoparticles were synthesized, characterized and used for lysozyme (Ly) and bovine serum albumin (BSA) adsorption. SiO₂, carbon nanotubes (CNTs) and graphene were used for covering the readily synthesized magnetite nanoparticles to elucidate the effect of cover layer on the protein adsorption kinetics and capacities of nanostructure. XRD, FTIR, AFM, SEM, VSM and fluorescence measurements were used for the characterization of the samples and investigating the adsorption kinetics of Ly and BSA by these nanoparticles. The average particle size of the Fe₃O₄ nanoparticles are approximately found as 10nm and VSM measurement shows that the Fe₃O₄ particles have superparamagnetic behavior with no hysteresis and remnant. The adsorption kinetic of proteins on nanosized material is followed via fluorescence method. All the nanostructures with different cover layers obey pseudo first order kinetics and SiO₂ coated nanoparticles show the fastest kinetics and capabilities for Ly and BSA adsorption.

Solution-phase synthesis of transition metal oxide nanocrystals: Morphologies, formulae, and mechanisms

In this review, we provide a broad overview of solution-phase synthesis of transition metal oxide nanocrystals (NCs), including a substantial catalog of published methods, and a unifying classification and discussion. Prevalent subcategories of solution-phase synthesis are delineated and general features are summarized. The diverse morphologies achievable by solution-phase synthesis are defined and exemplified. This is followed by sequential consideration of the solution-phase synthesis of first-row transition metal oxides. The common oxides of Ti, V, Mn, Fe, Co, Ni, Cu, and Zn are introduced; major crystal lattices are presented and illustrated; representative examples are explained; and numerous synthesis formulae are tabulated. Following this presentation of experimental studies, we present an introduction to theories of NC nucleation and growth. Various models of NC nucleation and growth are addressed, and important concepts determining the growth and structure of colloidal NCs are explained. Overall, this review provides an entry into systematic understanding of solution-phase synthesis of nanocrystals, with a reasonably comprehensive survey of results for the important category of transition metal oxide NCs.

Magnetic silk fibroin e-gel scaffolds for bone tissue engineering applications

Recently, the incorporation of magnetic nanoparticles into standard scaffolds has emerged as a promising approach for tissue engineering applications. This strategy can promote not only tissue regeneration but also reloading of scaffolds through an external supervising center that adsorbs growth factors, preserving their stability and biological activity. In this study, novel magnetic silk fibroin e-gel scaffolds were prepared by the electrogelation process of concentrated Bombyx mori silk fibroin (8 wt%) aqueous solution. In addition, basic fibroblast growth factor was conjugated physically to human serum albumin = Fe3O4 nanoparticles (71.52 ± 2.3 nm in size) with 97.5% binding yield. Scanning electron microscopy images of the prepared human serum albumin = Fe3O4-basic fibroblast growth factor-loaded silk fibroin e-gel scaffolds showed a three-dimensional porous morphology. In terms of water uptake, basic fibroblast growth factor-conjugated scaffolds had the highest water absorbability among all groups. In vitro cell culture studies showed that both the human serum albumin coating of Fe3O4 nanoparticle surface and basic fibroblast growth factor conjugation had an inductive effect on cell viability. One of the most used markers of bone formation and osteoblast differentiation is alkaline phosphatase activity; human serum albumin = Fe3O4-basic fibroblast growth factor-loaded silk fibroin e-gels showed significantly enhanced alkaline phosphatase activity (p < 0.05). SaOS-2 cells cultured on human serum albumin = Fe3O4-basic fibroblast growth factor-loaded silk fibroin e-gels deposited more calcium compared with those cultured on bare silk fibroin e-gels. These results indicated that the proposed e-gel scaffolds are valuable candidates for magnetic guiding in bone tissue regeneration, and they will present new perspectives for magnetic field application in regenerative medicine.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Albumin Carriers for Cancer Theranostics: A Conventional Platform with New Promise

Theranostic nanoplatforms with integrated diagnostic and therapeutic functions, aiming at imaging-guided therapy to improve treatment planning, as well as combination therapy to enhance treatment efficacy, have received tremendous attention in recent years. Among numerous types of functional nanomaterials explored in this field, protein-based nanocarriers with inherent biocompatibility have also been selected as building blocks to construct multifunctional theranostic platforms. In particular, albumin, which has been extensively used as drug-delivery carriers for decades, has shown great new promise in the construction of novel imaging and therapeutic nanoagents, as demonstrated by a number of recent studies. IHere, the motivations of using albumins to build up nanoscale theranostics are discussed, and the latest progress/future perspectives in this direction are summarized.

Controlled-release of Bacillus thurigiensis formulations encapsulated in light-resistant colloidosomal microcapsules for the management of lepidopteran pests of Brassica crops

Bacillus thuringiensis (B. t.) based formulations have been widely used to control lepidopteran pests in agriculture and forestry. One of their weaknesses is their short residual activity when sprayed in the field. Using Pickering emulsions, mixtures of spores and crystals from three B. t. serovars were successfully encapsulated in colloïdosomal microparticles (50 μm) using innocuous chemicals (acrylic particles, sunflower oil, iron oxide nanoparticles, ethanol and water). A pH trigger mechanism was incorporated within the particles so that B. t. release occurred only at pH > 8.5 which corresponds to the midgut pH of the target pests. Laboratory assays performed on Trichoplusia ni (T. ni) larvae demonstrated that the microencapsulation process did not impair B. t. bioactivity. The best formulations were field-tested on three key lepidopteran pests that attack Brassica crops, i.e., the imported cabbageworm, the cabbage looper and the diamondback moth. After 12 days, the mean number of larvae was significantly lower in microencapsulated formulations than in a commercial B. t. formulation, and the effect of microencapsulated formulations was comparable to a chemical pesticide (lambda-cyhalothrin). Therefore, colloïdosomal microcapsule formulations successfully extend the bioactivity of B. t. for the management of lepidopteran pests of Brassica crops.

Synthesis of Acylated Xylan-Based Magnetic Fe₃O₄ Hydrogels and Their Application for H₂O₂ Detection

Acylated xylan-based magnetic Fe₃O₄ nanocomposite hydrogels (ACX-MNP-gels) were prepared by fabricating Fe₃O₄ nanoctahedra in situ within a hydrogel matrix which was synthesized by the copolymerization of acylated xylan (ACX) with acrylamide and N-isopropylacrylamide under ultraviolet irradiation. The size of the Fe₃O₄ fabricated within the hydrogel matrix could be adjusted through controlling the crosslinking concentrations (C). The magnetic hydrogels showed desirable magnetic and mechanical properties, which were confirmed by XRD, Raman spectroscopy, physical property measurement system, SEM, TGA, and compression test. Moreover, the catalytic performance of the magnetic hydrogels was explored. The magnetic hydrogels (C = 7.5 wt %) presented excellent catalytic activity and provided a sensitive response to H₂O₂ detection even at a concentration level of 5 × 10^-6 mol·L^-1. This approach to preparing magnetic hydrogels loaded with Fe₃O₄ nanoparticles endows xylan-based hydrogels with new promising applications in biotechnology and environmental chemistry.

Covalent bridging of surface functionalized Fe3O4 and YPO4:Eu nanostructures for simultaneous imaging and therapy

Magnetic luminescent hybrid nanostructures (MLHN) have received a great deal of attention due to their potential biomedical applications such as thermal therapy, magnetic resonance imaging, drug delivery and intracellular imaging. We report the development of bifunctional Fe3O4 decorated YPO4:Eu hybrid nanostructures by covalent bridging of carboxyl PEGylated Fe3O4 and amine functionalized YPO4:Eu particles. The surface functionalization of individual nanoparticulates as well as their successful conjugation was evident from Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta-potential and transmission electron microscopy (TEM) studies. X-ray diffraction (XRD) analysis reveals the formation of highly crystalline hybrid nanostructures. TEM micrographs clearly show the binding/anchoring of 10 nm Fe3O4 nanoparticles onto the surface of 100-150 nm rice grain shaped YPO4:Eu nanostructures. These MLHN show good colloidal stability, magnetic field responsivity and self-heating capacity under an external AC magnetic field. The induction heating studies confirmed localized heating of MLHN under an AC magnetic field with a high specific absorption rate. Photoluminescence spectroscopy and fluorescence microscopy results show optical imaging capability of MLHN. Furthermore, successful internalization of these MLHN in the cells and their cellular imaging ability are confirmed from confocal microscopy imaging. Specifically, the hybrid nanostructure provides an excellent platform to integrate luminescent and magnetic materials into one single entity that can be used as a potential tool for hyperthermia treatment of cancer and cellular imaging.

The efficiency of magnetic hyperthermia and in vivo histocompatibility for human-like collagen protein-coated magnetic nanoparticles

Magnetic hyperthermia is a promising technique for the minimally invasive elimination of solid tumors. In this study, uniform magnetite nanoparticles (MNPs) with different particle sizes were used as a model system to investigate the size and surface effects of human-like collagen protein-coated MNPs (HLC-MNPs) on specific absorption rate and biocompatibility. It was found that these HLC-MNPs possess rapid heating capacity upon alternating magnetic field exposure compared to that of MNPs without HLC coating, irrespective of the size of MNPs. The significant enhancement of specific absorption rate is favorable for larger sized nanoparticles. Such behavior is attributed to the reduced aggregation and increased stability of the HLC-MNPs. By coating HLC on the surface of certain sized MNPs, a significant increase in cell viability (up to 2.5-fold) can be achieved. After subcutaneous injection of HLC-MNPs into the back of Kunming mice, it was observed that the inflammatory reaction hardly occurred in the injection site. However, there was a significant presence of phagocytes and endocytosis after the injection of nonconjugated counterparts. The overall strategy to fabricate HLC-MNPs can serve as a general guideline to address the current challenges in clinical magnetic hyperthermia, improved biocompatibility, and enhanced heating characteristics through protein coating.

Magnetic assembly of 3D cell clusters: visualizing the formation of an engineered tissue

OBJECTIVES

Contactless magnetic assembly of cells into 3D clusters has been proposed as a novel means for 3D tissue culture that eliminates the need for artificial scaffolds. However, thus far its efficacy has only been studied by comparing expression levels of generic proteins. Here, it has been evaluated by visualizing the evolution of cell clusters assembled by magnetic forces, to examine their resemblance to in vivo tissues.

MATERIALS AND METHODS

Cells were labeled with magnetic nanoparticles, then assembled into 3D clusters using magnetic force. Scanning electron microscopy was used to image intercellular interactions and morphological features of the clusters.

RESULTS

When cells were held together by magnetic forces for a single day, they formed intercellular contacts through extracellular fibers. These kept the clusters intact once the magnetic forces were removed, thus serving the primary function of scaffolds. The cells self-organized into constructs consistent with the corresponding tissues in vivo. Epithelial cells formed sheets while fibroblasts formed spheroids and exhibited position-dependent morphological heterogeneity. Cells on the periphery of a cluster were flattened while those within were spheroidal, a well-known characteristic of connective tissues in vivo.

CONCLUSIONS

Cells assembled by magnetic forces presented visual features representative of their in vivo states but largely absent in monolayers. This established the efficacy of contactless assembly as a means to fabricate in vitro tissue models.

PEGylated Carbon Nanocapsule: A Universal Reactor and Carrier for In Vivo Delivery of Hydrophobic and Hydrophilic Nanoparticles

We have developed PEGylated mesoporous carbon nanocapsule as a universal nanoreactor and carrier for the delivery of highly crystalline hydrophobic/hydrophilic nanoparticles (NPs) which shows superior biocompatibility, dispersion in body fluids, good biodistribution and NPs independent cellular uptake mechanism. The hydrophobic/hydrophilic NPs without surface modification were synthesized in situ inside the cavities of mesoporous carbon capsules (200-850 nm). Stable and inert nature of carbon capsules in a wide range of reaction conditions like high temperature and harsh solvents, make it suitable for being used as nano/microreactors for the syntheses of a variety of NPs for bioimaging applications, such as NaYF4:Eu(3+)(5%), LaVO4:Eu(3+)(10%), GdVO4:Eu(3+)(10%), Y2O3:Eu(3+)(5%), GdF3:Tb(3+)(10%), Mo, Pt, Pd, Au, and Ag. Multiple types of NPs (Y2O3:Eu(3+)(5%) (hydrophobic) and GdF3:Tb(3+)(10%) (hydrophilic)) were coloaded inside the carbon capsules to create a multimodal agent for magneto-fluorescence imaging. Our in vivo study clearly suggests that carbon capsules have biodistribution in many organs including liver, heart, spleen, lungs, blood pool, and muscles.