Targeted nanoscale magnetic hyperthermia: challenges and potentials of peptide-based targeting

Magnetic Cell Targeting for Cardiovascular Tissue Engineering

There is a critical need for novel approaches to translate cell therapy and regenerative medicine to clinical practice. Magnetic cell targeting with site specificity has started to open avenues in these fields as a potential therapeutic platform. Magnetic targeting is gaining popularity in the field of biomedicine due to its ability to concentrate and retain at a target site while minimizing deleterious effects at off-target sites. It is regarded as a relatively straightforward and safe approach for a wide range of therapeutic applications. This review discusses the latest advancements and approaches in magnetic cell targeting using endocytosed and surface-bound magnetic nanoparticles as well as in vivo tracking using magnetic resonance imaging (MRI). The most common form of magnetic nanoparticles is superparamagnetic iron oxide nanoparticles (SPION). The biodegradable and biocompatible properties of these magnetically responsive particles and capacity for rapid endocytosis into cells make them a breakthrough in targeted therapy. This review further discusses specific applications of magnetic targeting approaches in cardiovascular tissue engineering including myocardial regeneration, therapeutic angiogenesis, and endothelialization of implantable cardiovascular devices.

Magnetic Particle Imaging-Guided Hyperthermia for Precise Treatment of Cancer: Review, Challenges, and Prospects

Magnetic particle imaging (MPI) is a novel quantitative imaging technique using the nonlinear magnetization behavior of magnetic nanoparticles (MNPs) to determine their local concentration. Magnetic fluid hyperthermia (MFH) is a promising non-invasive therapy using the heating effects of MNPs. MPI-MFH is expected to enable real-time MPI guidance, localized MFH, and non-invasive temperature monitoring, which shows great potential for precise treatment of cancer. In this review, we introduce the fundamentals of MPI and MFH and their applications in the treatment of cancer. Also, we discuss the challenges and prospects of MPI-MFH.

Superstructures of water-dispersive hydrophobic nanocrystals: specific properties

Here, we describe water-soluble superstructures of hydrophobic nanocrystals that have been developed in recent years. We will also report on some of their properties which are still in their infancy. One of these structures, called "cluster structures", consists of hydrophobic 3D superlattices of Co or Au nanocrystals, covered with organic molecules acting like parachutes. The magnetic properties of Co "cluster structures" a retained when the superstructures is dispersed in aqueous solution. With Au "cluster structures", the longer wavelength optical scattered spectra are very broad and red-shifted, while at shorter wavelengths the localized surface plasmonic resonance of the scattered nanocrystals is retained. Moreover, the maximum of the long-wavelength signal spectra is linearly dependent on the increase in assembly size. The second superstructure was based on liquid-liquid instabilities favoring the formation of Fe3O4 nanocrystal shells (colloidosomes) filled or unfilled with Au 3D superlattices and also spherical solid crystal structures are called supraballs. Colloidosomes and supraballs in contact with cancer cells increase the density of nanocrystals in lysosomes and near the lysosomal membrane. Importantly, the structure of their organization is maintained in lysosomes for up to 8 days after internalization, while the initially dispersed hydrophilic nanocrystals are randomly aggregated. These two structures act as nanoheaters. Indeed, due to the dilution of the metallic phase, the penetration depth of visible light is much greater than that of homogeneous metallic nanoparticles of similar size. This allows for a high average heat load overall. Thus, the organic matrix acts as an internal reservoir for efficient energy accumulation within a few hundred picoseconds. A similar behavior was observed with colloidosomes, supraballs and "egg" structures, making these superstructures universal nanoheaters, and the same behavior is not observed when they are not dispersed in water (dried and deposited on a substrate). Note that colloidosomes and supraballs trigger local photothermal damage inaccessible to isolated nanocrystals and not predicted by global temperature measurements.

Nanosponges- Versatile Platform as Drug Carrier

BACKGROUND

Recently, nano-drug delivery systems have become an integral part of the most novel drug delivery systems and have gained considerable importance owing to various advantages such as carriers for poorly soluble drugs, targeting molecules at the desired site, protection from degradation etc. Objective: One of the most studied areas of nanotechnology is nanosponges. The objective of this review was to extensively summarize the various strategies for the preparation, characterization and applications of nanosponges.

METHODS

In the current mini-review, we conducted a systemic search of the literature and patent inventions focusing on nanosponges. The summary of the search was inclusive of various aspects of nanosponges, such as drug characteristics to be considered while incorporating in nanosponges, other crucial additives during formulation of nanosponges, methods of preparation, characterization and applications of nanosponges in pharmaceuticals.

RESULTS

Nanosponges are nanocarriers for both lipophilic and hydrophilic drugs. These are prepared by different methods such as emulsion-solvent evaporation, solvent method, melting method, ultrasound assisted method etc., and all these methods were less time consuming, more economical and evaluated by sophisticated techniques available for routine analysis. These are among the most feasible alternative to address several formulation difficulties associated with the physicochemical properties of the drug. The porous nature and small particle size are vital properties of the nanosponges that contribute crucially to correcting the drawbacks of the drug. The properties of the nanosponges can be enhanced when combined with cyclodextrins. Extensive research work has been carried out in past to explore cyclodextrin based nanosponges. Besides, it is also used for smart targeting of tumors and for drug release in a sustainable pattern. Nanosponges can be prepared by simple methods. These can be tuned to release the drug by different routes so as to achieve the maximum benefits of the drug.

CONCLUSION

Huge amount of research has been carried out on nanosponges as drug carrier. The method of preparation and characterization of nanosponges are quite economical and routinely available. Owing to potential benefits and probable applications, these can be used as efficient carriers for certain drugs. The authors expect that the current review will guide the investigation of the nanosponges as nanodrug delivery systems.

Development and Evaluation of a Film Forming System Containing Myricetin and Miconazole Nitrate for Preventing Candida albicans Catheter-Related Infection

Background: Candida albicans catheter-related infection (CRI) is a great challenge in clinic now, mainly due to the difficulty in eradicating the biofilms. Purpose: In this study, the mechanism of the antibiofilm effect of myricetin (MY) on C. albicans was illustrated. A film forming system (FFS) containing MY and miconazole nitrate (MN) was developed, optimized, and evaluated. The anti-infection effect of MY+MN@FFS against C. albicans CRI was investigated in vivo. Study Design and Methods: To clarify the mechanism of the action of MY, the influence of MY on each key process of the formation of C. albicans biofilms was evaluated. To deliver MY and MN into the skin and form a drug reservoir on the surface of the skin, the FFS was used as a carrier and MY+MN@FFS was developed, optimized, and evaluated. After preliminary confirmation of drug safety, a percutaneously inserted C. albicans CRI mouse model was established to investigate the in vivo anti-infection effect of MY+MN@FFS by fluorescence microscopy and scanning electron microscopy on the outer surface of the catheters, hematoxylin/eosin staining, and periodic acid-Schiff staining of the mice skin tissues. Results: MY was found to inhibit the morphological transition of C. albicans and the secretion of exopolysaccharides, resulting in a reduction in biofilms. MY+MN@FFS exhibited excellent properties and no irritation to mice skin. In an in vivo anti-infection study, MY+MN@FFS exhibited an excellent preventive effect against percutaneously inserted C. albicans CRI. Conclusion: MY+MN@FFS might be a potential approach for effectively preventing percutaneously inserted C. albicans CRI in clinic.

Fabrication of core-shell type poly(NIPAm)-encapsulated citral and its application on bamboo as an anti-molding coating

Bamboo is a widely used renewable and degradable biomass material; however, its sustainable utilisation is hindered by its susceptibility to mold. The current bamboo anti-mold technology is mainly based on organic chemical agents; these agents can easily induce mold resistance in bamboo with long-term use, and can even adversely affect human health. In the present study, the poly(N-isopropyl acrylamide) (PNIPAm)/citral nanohydrogel was prepared by encapsulating the natural antibiotic citral in PNIPAm for the anti-mold treatment of bamboo. The results revealed that this nanohydrogel exhibited a core-shell system with citral as the 'core' and PNIPAm as the 'shell', an average hydrodynamic diameter of 88.1 nm, and a low critical solution temperature (LCST) of 35.4 °C. After the high-pressure impregnation with the nanohydrogel, the bamboo strips showed excellent control effects toward common bamboo molds. Therefore, the nanohydrogel demonstrated high efficiency and it may become an ideal alternative to organic chemical anti-mold agents, thus showcasing its significant potential in the field of mold prevention for bamboo.

Microsponge Based Gel of Tea Tree Oil for Dermatological Microbial Infections

Objective:

Tea Tree Oil (TTO), derived from Melaleuca alternifolia possesses broad spectrum antimicrobial potential. However, its therapeutic utility is impaired due to its high volatility, poor aqueous solubility and low stability in the presence of light, oxygen and temperature. The present study was attempted to investigate Ethyl Cellulose (EC) microsponges (MSs) as topical carriers for TTO to circumvent above mentioned limitations.

Methods:

TTO MSs were prepared using quasi emulsion solvent diffusion technique. The effect of formulation variables on the production yield, entrapment efficiency, particle size and drug release of MSs was investigated. The optimized MSs were dispersed into Carbopol 934 gel and evaluated for drug release, skin irritation, antibacterial activity and photostability.

Results:

Scanning electron microscopy revealed spherical and porous nature of TTO microsponges. The optimized MSs possessed particle size of 36.98 μm, percent entrapment efficiency of 93.12% and percent cumulative drug release of 79.18%, respectively. MS-loaded gels were found nonirritant. In addition, TTO loaded MS gels exhibited good stability. Antimicrobial effect of TTO MS gel showed broader zones of inhibition in comparison to TTO gel.

Conclusion:

The findings of our study suggest that MS loaded gel could prove alternative to conventional antibacterial formulations for dermatological microbial infections.

Ecofriendly Ethyl Cellulose Microsponges of Citronella Oil: Preparation, Characterization and Evaluation of Cytotoxicity and Larvicidal assay

Background:

Citronella Oil (CO) was used by the Indian army as mosquito repellant to repel mosquitoes at the beginning of the 20th century and later in 1948, it was registered in the USA for commercial purposes. Due to its ecofriendly nature, CO possesses immense potential as a mosquito repellent.

Methods:

Citronella oil is a valuable alternative to synthetic mosquito repellents commonly used nowadays. However, its volatile nature, poor stability in air and high temperature restrict its application. Its direct application on skin may lead to skin irritation. To surmount the above-mentioned issues, the present research aims to develop Microsponge (MS), a novel dosage form for enhancing the utility and safety of CO. Quasi emulsion solvent diffusion method was chosen for crafting MS using ethyl cellulose with various drug-polymer ratios and characterized. In vitro cytotoxicity evaluation was also carried out to check the dermal safety of COMS.

Results:

The present results revealed that the size of all prepared formulation lies in the micro range (20 ± 3 to 41 ± 4 μm), with good payload (42.09± 3.24 to 67.08± 6.43%). The results of FE-SEM depicted that MS were spherical in shape with porous nature. Cytotoxicity results indicated that COMS were safe on skin cells, when compared to pure CO. The optimized MS were also assessed for larvicidal assay against larvae of Anopheles culicifacies.

Conclusion:

The CO micro-formulations were found to possess enhanced stability of this oil. Entrapment of CO in MS resulted in a better vehicle system in terms of safety, stability and handling benefits of this oil.

High-throughput chemical and chemoenzymatic approaches to saccharide-coated magnetic nanoparticles for MRI

There is a need for biofunctionalised magnetic nanoparticles for many biomedical applications, including MRI contrast agents that have a range of surface properties and functional groups. A library of eleven adducts, each formed by condensing a reducing sugar with a catechol hydrazide, for nanoparticle functionalisation has been created using a high-throughput chemical synthesis methodology. The enzymatic transformation of an N-acetylglucosamine (GlcNAc) adduct into an N-acetyllactosamine adduct by β-1,4-galactosyltransferase illustrates how chemoenzymatic methods could provide adducts bearing complex and expensive glycans. Superparamagnetic iron oxide nanoparticles (8 nm diameter, characterised by TEM, DLS and SQUID) were coated with these adducts and the magnetic resonance imaging (MRI) properties of GlcNAc-labelled nanoparticles were determined. This straightforward approach can produce a range of MRI contrast agents with a variety of biofunctionalised surfaces.

Nanodispersions stabilized by β-cyclodextrin nanosponges: application for simultaneous enhancement of bioactivity and stability of sage essential oil

The aim of this work was to stabilize oil-in-water nanoemulsion containing sage (salvia officinalis) essential oil, for enhancing its physicochemical stability and enlarging its industrial applications. New β-cyclodextrin nanosponges were synthesized by polycondensation using naphthalene dicarboxylic acid as cross-linking agent, the latter system was characterized by FTIR spectroscopy, SEM, BET, and powder XRD. Nanoemulsions stabilized by free β-cyclodextrin or nanosponges were prepared, their physicochemical properties were determined (particles size, zeta potential, viscosity, turbidity, and essential oil content) and their stability was studied at different storage temperatures (4 °C, 20 °C, and 40 °C) during 3 months. Pharmaceutical application of prepared nanoemulsions was investigated in vitro by dissolution test study and in vivo by their antidiabetic activity evaluation in rats. Sage essential oil nanoemulsion stabilized by β-cyclodextrin-naphthalene dicarboxylic acid nanosponges presents very high stability and promising uses in pharmaceutical industry.

Combined Treatments of Magnetic Intra-Lysosomal Hyperthermia with Doxorubicin Promotes Synergistic Anti-Tumoral Activity

Doxorubicin is a cytotoxic drug used for the treatment of many cancer types. However, its significant dose-related adverse effects including cardiotoxicity may hamper its efficiency. Moreover, the multidrug resistance that appears during treatments limits anti-cancer therapies. Hyperthermia has been introduced as an adjuvant anti-cancer therapy and presents promising opportunities especially in combination with chemotherapy. However, hyperthermia methods including standard magnetic hyperthermia do not discriminate between the target and the surrounding normal tissues and can lead to side effects. In this context, a Magnetic Intra-Lysosomal Hyperthermia (MILH) approach, which occurs without perceptible temperature rise, has been developed. We previously showed that minute amounts of iron oxide magnetic nanoparticles targeting the gastrin receptor (CCK2R) are internalized by cancer cells through a CCK2R-dependent physiological process, accumulated into their lysosomes and kill cancer cells upon high frequency alternating magnetic field (AMF) application through lysosomal cell death. Here, we show that the combination of MILH with doxorubicin increases the efficiency of the eradication of endocrine tumor cells with synergism. We also demonstrate that these two treatments activate two different cell death pathways that are respectively dependent on Caspase-1 and Caspase-3 activation. These findings will result in the development of new anti-tumoral, intra-lysosomal-thermo/chemotherapy with better curative effects than chemotherapy alone and that are devoid of adverse effects linked to standard hyperthermia approaches.

Advances in Magnetic Nanoparticles for Biomedical Applications

Magnetic nanoparticles (NPs) are emerging as an important class of biomedical functional nanomaterials in areas such as hyperthermia, drug release, tissue engineering, theranostic, and lab-on-a-chip, due to their exclusive chemical and physical properties. Although some works can be found reviewing the main application of magnetic NPs in the area of biomedical engineering, recent and intense progress on magnetic nanoparticle research, from synthesis to surface functionalization strategies, demands for a work that includes, summarizes, and debates current directions and ongoing advancements in this research field. Thus, the present work addresses the structure, synthesis, properties, and the incorporation of magnetic NPs in nanocomposites, highlighting the most relevant effects of the synthesis on the magnetic and structural properties of the magnetic NPs and how these effects limit their utilization in the biomedical area. Furthermore, this review next focuses on the application of magnetic NPs on the biomedical field. Finally, a discussion of the main challenges and an outlook of the future developments in the use of magnetic NPs for advanced biomedical applications are critically provided.

Enhancement of Bioavailability of Non-nucleoside Reverse Transciptase Inhibitor Using Nanosponges

Efavirenz is a non-nucleoside reverse transcriptase inhibitor which is chronically prescribed for HIV patients. However, it exhibits solubility-limited bioavailability. Aim of this work was to enhance the solubility and dissolution of the Biopharmaceutical Classification System (BCS) class II drug efavirenz, using beta-cyclodextrin-based nanosponges. Nanosponges have high drug loading capacity and are effective for solubility enhancement. Beta-cyclodextrin was crosslinked with carbonates in different ratios to prepare nanosponges. The nanosponges were loaded with efavirenz by solvent evaporation method and the nanosponge with higher drug loading capacity was selected for further studies. Binary and ternary complexes with EFA, NS, and PVP K30 were prepared and characterized by phase solubility, solution state interaction, saturation solubility, in vitro dissolution, and in vivo pharmacokinetics. Spectral analysis by Fourier transform infrared spectroscopy, powder X-ray diffraction, differential scanning calorimetry, and field emission scanning electron microscopy was performed. Results obtained from spectral characterization confirmed inclusion complexation. Stability constant for ternary complex was found to be 1997 lit/mole, which indicates stable complex formation. The saturation solubility was found to be 17-fold higher with ternary complex in distilled water and about 4-fold in simulated gastric fluid. In vitro dissolution was improved 3 folds with ternary complex. Ternary nanosponge complexes were found to have 2-fold increase in oral bioavailability of efavirenz as compared to plain drug.

A 32full factorial design for development and characterization of a nanosponge-based intravaginal in situ gelling system for vulvovaginal candidiasis

The rationale behind present research effort was to enhance CTZ solubility and efficacyviaforming complex with hydroxypropyl β-cyclodextrin (HP-β-CD) nanosponges.

Multi-modal MR imaging and magnetic hyperthermia study of Gd doped Fe3O4 nanoparticles for integrative cancer therapy

Gadolinium (Gd) doped iron oxide nano-mediator in cancer theranostics are one of the most promising candidates in combining diagnostics (imaging) and therapeutics (molecular therapy) functions in a single, multimodal platform.

Design of magnetic molecularly imprinted polymer nanoparticles for controlled release of doxorubicin under an alternative magnetic field in athermal conditions

An innovative magnetic delivery nanomaterial for triggered cancer therapy showing active control over drug release by using an alternative magnetic field is proposed. In vitro and In vivo release of doxorubicin (DOX) were investigated and showed a massive DOX release under an alternative magnetic field without temperature elevation of the medium.