Phoenix

A novel chiral coordination polymer, [Cu­(C₆H₅CH­(OH)­COO)­(μ-C₆H₅CH­(OH)­COO)] (<b>1</b>-L and <b>1</b>-D), was synthesized through a reaction of copper acetate with l-mandelic acid at room temperature. Although previously reported copper mandelate prepared by hydrothermal reaction was a centrosymmetric coordination polymer because of the racemization of mandelic acid, the current coordination polymer shows noncentrosymmetry and a completely different structure from that previously reported. The X-ray crystallography for <b>1</b>-L revealed that the copper center of the compound showed a highly distorted octahedral structure bridged by a chiral mandelate ligand in the unusual coordination mode to construct a one-dimensional (1D) zigzag chain structure. These 1D chains interdigitated each other to give a layered structure as a result of the formation of multiple aromatic interactions and hydrogen bonds between hydroxyl and carboxylate moieties at mandelate ligands. The coordination polymer <b>1</b>-L belongs to the noncentrosymmetric space group of C2 to show piezoelectric properties and second harmonic generation (SHG) activity

Theranostic Nanoparticles for MRI-Guided Thermochemotherapy: “Tight” Clustering of Magnetic Nanoparticles Boosts Relaxivity and Heat-Generation Power

Magnetic-resonance-imaging (MRI)-guided magnetic thermochemotherapy is a potentially invasive technique combining diagnosis and treatment. It requires the development of multifunctional nanoparticles with (1) biocompatibility, (2) high relaxivity, (3) high heat-generation power, (4) controlled drug release, and (5) tumor targeting. Here, we show the synthesis of such multifunctional nanoparticles (“Core–Shells”) and the feasibility of MRI-guided magnetic thermochemotherapy using the synthesized nanoparticles. “Tight” iron-oxide nanoparticle clustering to zero interparticle distance within the Core–Shells boosts the relaxivity and heat-generation power while maintaining biocompatibility. The initial Core–Shell drug release occurs in response to an alternating magnetic field (AMF) and continues gradually after removal of the AMF. Thus, a single Core–Shell dose realizes continuous chemotherapy over a period of days or weeks. The Core–Shells accumulate in abdomen tumors, facilitating MRI visualization. Subsequent AMF application induces heat generation and drug release within the tumors, inhibiting their growth. Core–Shell magnetic thermochemotherapy exhibits significantly higher therapeutic efficacy than both magnetic hyperthermia and chemotherapy alone. More importantly, there are minimal side effects. The findings of this study introduce new perspectives regarding the development of materials for MRI, magnetic hyperthermia, and drug delivery systems. Both conventional and novel iron-oxide-based materials may render theranostics (i.e., techniques fusing diagnosis and treatment) feasible

Organic–Inorganic Hybrid Nanoparticles for Tracking the Same Cells Seamlessly at the Cellular, Tissue, and Whole Body Levels

Techniques to elucidate the kinetics and distribution of the same cells in the whole body and in tissues are necessary for further studies of cancer, immunity, and regenerative medicine. Fluorescent imaging is a powerful technique for visualization of cells. However, current fluorescent probes are applicable in either the ultraviolet (UV)–visible (Vis) region (300–650 nm) or the biological transparency window (BTW, 650–900 nm), but not both. Thus, they cannot serve as fluorescent probes for both in vivo and in vitro imaging, and it is difficult to achieve imaging of the same cells seamlessly from the cellular level to the whole body and tissue levels using currently available fluorescent probes. Accordingly, in this paper, we describe organic–inorganic hybrid nanoparticles (HNPs) that could be used to achieve seamless tracking of the same cells. Within the HNPs, a porphyrin molecule, Vis-fluorophore, was surrounded by a siloxane chain, preventing the aggregation of porphyrin molecules. As a result, the porphyrin fluorescence was not quenched. Furthermore, indocyanine green (ICG), a BTW fluorophore, was localized on the HNP surface, leading to fluorescence resonance energy transfer (FRET) from porphyrin to ICG only near the HNP surface. Through the above structural design, the HNPs acquired both excitation (λ_ex) and emission (λ_em) wavelengths in the visible region and BTW, respectively, as well as large Stokes shifts. The HNP-labeled immune cells successfully and the labeled cells were separated easily from unlabeled cells by fluorescence-activated cell sorting. The kinetics of the labeled cells in the whole body were revealed by fluorescence imaging within BTW. Furthermore, the distributions of the same labeled cells were elucidated by histological analysis within the UV–vis region. Thus, the HNPs served as fluorescent probes for seamless tracking of the same cells

Red Blood Cell-Shaped Microparticles with a Red Blood Cell Membrane Demonstrate Prolonged Circulation Time in Blood

Prolonging the circulation time (CT) of microparticles (MPs) in the blood is key for a successful microparticle-based medicinal approach to serve as drug delivery systems (DDSs). Previously, we reported that MPs that mimic the shape of red blood cells (RBCs) avoid accumulation in the spleen and lungs. We now describe the effectiveness of mimicking not only the shape of RBCs but also their surface structure for the prolongation of CT. RBC-shaped MPs (RBC-MPs) were electrosprayed with cellulose and covered with a native RBC membrane (RBCM) collected from mouse blood. Seven hours after intravenous injection, approximately twice as many RBCM-covered RBC-MPs (RBC-MPs@RBCM) were present in the blood of mice compared to unmodified RBC-MPs. Twenty-four hours postinjection, the concentration of RBC-MPs@RBCM in the blood was 4 times higher. These findings suggest that an RBCM covering the MPs contributed to significant CT prolongation, which may positively impact their applications as DDSs