Theranostic magnetic nanoparticles for efficient capture and in situ chemotherapy of circulating tumor cells

Multifunctional Iron Oxide Nanoparticles as Promising Magnetic Biomaterials in Drug Delivery: A Review

A wide range of applications using functionalized magnetic nanoparticles (MNPs) in biomedical applications, such as in biomedicine as well as in biotechnology, have been extensively expanding over the last years. Their potential is tremendous in delivery and targeting systems due to their advantages in biosubstance binding. By applying magnetic materials-based biomaterials to different organic polymers, highly advanced multifunctional bio-composites with high specificity, efficiency, and optimal bioavailability are designed and implemented in various bio-applications. In modern drug delivery, the importance of a successful therapy depends on the proper targeting of loaded bioactive components to specific sites in the body. MNPs are nanocarrier-based systems that are magnetically guided to specific regions using an external magnetic field. Therefore, MNPs are an excellent tool for different biomedical applications, in the form of imaging agents, sensors, drug delivery targets/vehicles, and diagnostic tools in managing disease therapy. A great contribution was made to improve engineering skills in surgical diagnosis, therapy, and treatment, while the advantages and applicability of MNPs have opened up a large scope of studies. This review highlights MNPs and their synthesis strategies, followed by surface functionalization techniques, which makes them promising magnetic biomaterials in biomedicine, with special emphasis on drug delivery. Mechanism of the delivery system with key factors affecting the drug delivery efficiency using MNPs are discussed, considering their toxicity and limitations as well.

Tailored Magnetic Multicore Nanoparticles for Use as Blood Pool MPI Tracers

For the preclinical development of magnetic particle imaging (MPI) in general, and the exploration of possible new clinical applications of MPI in particular, tailored MPI tracers with surface properties optimized for the intended use are needed. Here we present the synthesis of magnetic multicore particles (MCPs) modified with polyethylene glycol (PEG) for use as blood pool MPI tracers. To achieve the stealth effect the carboxylic groups of the parent MCP were activated and coupled with pegylated amines (mPEG-amines) with different PEG-chain lengths from 2 to 20 kDa. The resulting MCP-PEG variants with PEG-chain lengths of 10 kDa (MCP-PEG10K after one pegylation step and MCP-PEG10K2 after a second pegylation step) formed stable dispersions and showed strong evidence of a successful reaction of MCP and MCP-PEG10K with mPEG-amine with 10 kDa, while maintaining their magnetic properties. In rats, the mean blood half-lives, surprisingly, were 2 and 62 min, respectively, and therefore, for MCP-PEG10K2, dramatically extended compared to the parent MCP, presumably due to the higher PEG density on the particle surface, which may lead to a lower phagocytosis rate. Because of their significantly extended blood half-life, MCP-PEG10K2 are very promising as blood pool tracers for future in vivo cardiovascular MPI.

Review of the Mechanism of Nanocarriers and Technological Developments in the Field of Nanoparticles for Applications in Cancer Theragnostics

Cancer cannot be controlled by the usage of drugs alone, and thus, nanotechnology is an important technique that can provide the drug with an impetus to act more effectively. There is adequate availability of anticancer drugs that are classified as alkylating agents, hormones, or antimetabolites. Nanoparticle (NP) carriers increase the residence time of the drug, thereby enhancing the survival rate of the drug, which otherwise gets washed off owing to the small size of the drug particles by the excretory system. For example, for enhancing the circulation, a coating of nonfouling polymers like PEG and dextran is done. Famous drugs such as doxorubicin (DOX) are commonly encapsulated inside the nanocomposite. The various classes of nanoparticles are used to enhance drug delivery by aiding it to fight against the tumor. Targeted therapy aims to attack the cells with features common to the cancer cells while minimizing damage to the normal cell, and these therapies work in one in four ways. Some block the cancer cells from reproducing newer cells, others release toxic substances to kill the cancer cells, some stimulate the immune system to destroy the cancer cells, and some block the growth of more blood vessels around cancer cells, which starve the cells of the nutrients, which is needed for their growth. This review aims to testify the advancements nanotechnology has brought in cancer therapy, and its statements are supported with recent research findings and clinical trial results.

Biomimetic human lung-on-a-chip for modeling disease investigation

The lung is the primary respiratory organ of the human body and has a complicated and precise tissue structure. It comprises conductive airways formed by the trachea, bronchi and bronchioles, and many alveoli, the smallest functional units where gas-exchange occurs via the unique gas-liquid exchange interface known as the respiratory membrane. In vitro bionic simulation of the lung or its microenvironment, therefore, presents a great challenge, which requires the joint efforts of anatomy, physics, material science, cell biology, tissue engineering, and other disciplines. With the development of micromachining and miniaturization technology, the concept of a microfluidics-based organ-on-a-chip has received great attention. An organ-on-a-chip is a small cell-culture device that can accurately simulate tissue and organ functions in vitro and has the potential to replace animal models in evaluations of drug toxicity and efficacy. A lung-on-a-chip, as one of the first proposed and developed organs-on-a-chip, provides new strategies for designing a bionic lung cell microenvironment and for in vitro construction of lung disease models, and it is expected to promote the development of basic research and translational medicine in drug evaluation, toxicological detection, and disease model-building for the lung. This review summarizes current lungs-on-a-chip models based on the lung-related cellular microenvironment, including the latest advances described in studies of lung injury, inflammation, lung cancer, and pulmonary fibrosis. This model should see effective use in clinical medicine to promote the development of precision medicine and individualized diagnosis and treatment.

Magnetic iron oxide nanoparticles as drug carriers: preparation, conjugation and delivery

Magnetic nanoparticles (MNPs), particularly made of iron oxides, have been extensively studied as diagnostic imaging agents and therapeutic delivery vehicles. In this review, special emphasis is set on the 'recent advancements of drug-conjugated MNPs used for therapeutic applications'. The most prevalent preparation methods and chemical functionalization strategies required for translational biomedical nanoformulations are outlined. Particular attention is, then, devoted to the tailored conjugation of drugs to the MNP carrier according to either noncovalent or covalent attachments, with advantages and drawbacks of both pathways conferred. Notable examples are presented to demonstrate the advantages of MNPs in respective drug-delivery applications. Understanding of the preparation, conjugation and delivery processes will definitely bring, in the next decades, a novel magneto-nanovehicle for effective theranostics.

Novel magnetic multicore nanoparticles designed for MPI and other biomedical applications: From synthesis to first in vivo studies

Synthesis of novel magnetic multicore particles (MCP) in the nano range, involves alkaline precipitation of iron(II) chloride in the presence of atmospheric oxygen. This step yields green rust, which is oxidized to obtain magnetic nanoparticles, which probably consist of a magnetite/maghemite mixed-phase. Final growth and annealing at 90°C in the presence of a large excess of carboxymethyl dextran gives MCP very promising magnetic properties for magnetic particle imaging (MPI), an emerging medical imaging modality, and magnetic resonance imaging (MRI). The magnetic nanoparticles are biocompatible and thus potential candidates for future biomedical applications such as cardiovascular imaging, sentinel lymph node mapping in cancer patients, and stem cell tracking. The new MCP that we introduce here have three times higher magnetic particle spectroscopy performance at lower and middle harmonics and five times higher MPS signal strength at higher harmonics compared with Resovist®. In addition, the new MCP have also an improved in vivo MPI performance compared to Resovist®, and we here report the first in vivo MPI investigation of this new generation of magnetic nanoparticles.

Thermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen

Decades of research focused on size and shape control of iron oxide nanoparticles have led to methods of synthesis that afford excellent control over physical size and shape but comparatively poor control over magnetic properties. Popular synthesis methods based on thermal decomposition of organometallic precursors in the absence of oxygen have yielded particles with mixed iron oxide phases, crystal defects, and poorer than expected magnetic properties, including the existence of a thick "magnetically dead layer" experimentally evidenced by a magnetic diameter significantly smaller than the physical diameter. Here, we show how single-crystalline iron oxide nanoparticles with few defects and similar physical and magetic diameter distributions can be obtained by introducing molecular oxygen as one of the reactive species in the thermal decomposition synthesis. This is achieved without the need for any postsynthesis oxidation or thermal annealing. These results address a significant challenge in the synthesis of nanoparticles with predictable magnetic properties and could lead to advances in applications of magnetic nanoparticles.

Paclitaxel loaded magnetic nanocomposites with folate modified chitosan/carboxymethyl surface; a vehicle for imaging and targeted drug delivery

In this study, Paclitaxel (PTX) containing, bovine serum albumin (BSA) nanoparticles were fabricated via a simple approach. Folic acid (FA) was conjugated to chitosan (CS)/carboxymethyl cellulose (CMC) through an esterification reaction to produce BSA-CS-FA or BSA-CMC-FA conjugates. NiFe₂O₄ noncore (NFs) and PTX were loaded through a heat treatment and by a diffusion process. NFs-BSA-CS and NFs-BSA-CMC-FA with size of about 80nm, showed superior transversal R₂ relaxation rate of 349 (mM)^-1s^-1 along with folate receptor-targeted and magnetically directed functions. NFs-BSA-CS-FA or NFs-BSA-CS-FA were found stable and biocompatible. Application of an external magnetic field effectively enhanced the PTX release from PTX-NFs-BSA-CS-FA or PTX-NFs-BSA-CS-FA and hence tumor inhibition rate. This study validate that NFs-BSA-CS-FA or NFs-BSA-CMC-FA and PTX-NFs-BSA-CS-FA or PTX-NFs-BSA-CS-FA are suitable systems for tumor diagnosis and therapy.

A chip assisted immunomagnetic separation system for the efficient capture and in situ identification of circulating tumor cells

The detection of circulating tumor cells (CTCs), a kind of "liquid biopsy", represents a potential alternative to noninvasive detection, characterization and monitoring of carcinoma. Many previous studies have shown that the number of CTCs has a significant relationship with the stage of cancer. However, CTC enrichment and detection remain notoriously difficult because they are extremely rare in the bloodstream. Herein, aided by a microfluidic device, an immunomagnetic separation system was applied to efficiently capture and in situ identify circulating tumor cells. Magnetic nanospheres (MNs) were modified with an anti-epithelial-cell-adhesion-molecule (anti-EpCAM) antibody to fabricate immunomagnetic nanospheres (IMNs). IMNs were then loaded into the magnetic field controllable microfluidic chip to form uniform IMN patterns. The IMN patterns maintained good stability during the whole processes including enrichment, washing and identification. Apart from its simple manufacture process, the obtained microfluidic device was capable of capturing CTCs from the bloodstream with an efficiency higher than 94%. The captured cells could be directly visualized with an inverted fluorescence microscope in situ by immunocytochemistry (ICC) identification, which decreased cell loss effectively. Besides that, the CTCs could be recovered completely just by PBS washing after removal of the permanent magnets. It was observed that all the processes showed negligible influence on cell viability (viability up to 93%) and that the captured cells could be re-cultured for more than 5 passages after release without disassociating IMNs. In addition, the device was applied to clinical samples and almost all the samples from patients showed positive results, which suggests it could serve as a valuable tool for CTC enrichment and detection in the clinic.

Dual stimuli-responsive smart beads that allow “on–off” manipulation of cancer cells

Temperature- and electric field-responsive polymer-conjugated polystyrene beads, termed smart beads, are designed to isolate cancer cells.

An innovative pre-targeting strategy for tumor cell specific imaging and therapy

A programmed pre-targeting system for tumor cell imaging and targeting therapy was established based on the "biotin-avidin" interaction. In this programmed functional system, transferrin-biotin can be actively captured by tumor cells with the overexpression of transferrin receptors, thus achieving the pre-targeting modality. Depending upon avidin-biotin recognition, the attachment of multivalent FITC-avidin to biotinylated tumor cells not only offered the rapid fluorescence labelling, but also endowed the pre-targeted cells with targeting sites for the specifically designed biotinylated peptide nano-drug. Owing to the successful pre-targeting, tumorous HepG2 and HeLa cells were effectively distinguished from the normal 3T3 cells via fluorescence imaging. In addition, the self-assembled peptide nano-drug resulted in enhanced cell apoptosis in the observed HepG2 cells. The tumor cell specific pre-targeting strategy is applicable for a variety of different imaging and therapeutic agents for tumor treatments.

Selective Capture and Quick Detection of Targeting Cells with SERS-Coding Microsphere Suspension Chip

Circulating tumor cells (CTCs) captured from blood fluid represent recurrent cancers and metastatic lesions to monitor the situation of cancers. We develop surface-enhanced Raman scattering (SERS)-coding microsphere suspension chip as a new strategy for fast and efficient capture, recovery, and detection of targeting cancer cells. Using HeLa cells as model CTCs, we first utilize folate as a recognition molecule to be immobilized in magnetic composite microspheres for capturing HeLa cells and attaining high capturing efficacy (up to 95%). After capturing cells, the composite microsphere, which utilizes a disulfide bond as crosslinker in the polymer shell and as a spacer for linking folate, can recycle 90% cells within 20 min eluted by glutathion solution. Taking advantage of the SERS with fingerprint features, we characterize captured/recovered cells with the unique signal of report-molecule 4-aminothiophenol through introducing the SERS-coding microsphere suspension chip to CTCs. Finally, the exploratory experiment of sieving cells shows that the magnetic composite microspheres can selectively capture the HeLa cells from samples of mixed cells, indicating that these magnetic composite microspheres have potential in real blood samples for capturing CTCs.

Peptide-based isolation of circulating tumor cells by magnetic nanoparticles

A new CTC isolation method with high efficiency by using EpCAM recognition peptide functionalized magnetic nanoparticles was developed.

Amplified plasmonic detection of DNA hybridization using doxorubicin-capped gold particles

We show in this article that doxorubicin-modified gold nanoparticles (Au NP-DOX) can be used for the post-amplification of the wavelength shift of localized surface plasmon resonance (LSPR) signals after DNA hybridization events. We take advantage of the intercalation properties of DOX with guanine-rich oligonucleotides and the plasmon coupling between surface-linked gold nanostructures and Au NP-DOX in solution to detect in a sensitive manner DNA hybridisation events. Post-treatment of double-stranded DNA with Au NP-DOX resulted in a detection limit of ≈600 pM, several times lower than that without post-incubation (LOD ≈ 40 nM).