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A facile method to produce dextran-coated gold nanoparticles (DGNPs) for atherosclerosis detection using computed tomography (CT) imaging is developed. DGNPs are prepared using only pyrenyl dextran as a reducible stabilizer chemically conjugated with hydroxyl groups of dextran and carboxyl groups of pyrenyl molecules, which can reduce gold ions to gold particles and stably form gold nanoparticles in the aqueous phase. The physical properties of DGNPs can be controlled by the reaction time. DGNPs, where gold particles were stably covered with dextran, exhibit targeting ability against inflammatory macrophages with the help of strong interactions between dextran on their surface and scavenger receptors in the macrophages with good biocompatibility without cell damage. From the in vivo studies, DGNPs can be used to accurately detect atherosclerosis via CT imaging.

The polyaniline–carbon nanotube composite thin film bolometric near-infrared sensor exhibited more than a two orders of magnitude sensitivity enhancement over both the polyaniline thin film and carbon nanotube network NIR sensor. We also investigated the mechanism of the effectively enhanced sensitivity of the composite material and demonstrated that it is a synergistic effect due to the higher heat generation of carbon nanotubes and higher temperature coefficient of resistance of polyaniline.

We fabricated dextran-coated magnetic nanoclusters (Dex-MNCs) for targeted magnetic resonance (MR) imaging of inflammatory macrophages. Dex-MNCs were prepared through encapsulation of hydrophobic magnetic nanocrystals (MNCs) by pyrenyl dextran in order that MNCs could achieve increased colloidal stability in aqueous phase as well as strongly interact with macrophages. Dex-MNCs exhibited biocompatibility and sufficient targeting efficiency against macrophages with strengthened MR contrast effect from in vitro/in vivo studies. Considering these results, we confirmed that Dex-MNCs could accurately detect inflammatory macrophagevia MR imaging.

This feature article reviews the emerging applications of activatable nanomaterials in the bio- and medical fields, namely, molecular imaging, theragnostics, cancer therapy, tissue engineering, and biosensors. Nanomaterials, with an ideal size to interact with biological systems replete with nanoscopic biomolecules, are now finding applications in previously inconceivable tasks of affecting biological systems at the sub-cellular level, revolutionizing the technological developments of the bio- and medical fields. This feature article places special emphasis on the nanomaterial designs, the activation mechanism of the prepared materials and the nanoscopically localized effect of the resulting nanomaterial-originated events, which are designed to manipulate the behavior of biological systems or obtain critical biological information.

We fabricated de novo biocompatible mineral plasmon resonants for localized and systemic treatment of cancer. Biodegradable calcium-phosphate gold nanocomposites were synthesized for inducing a superior surface plasmon resonance effect. The combination of therapeutic antibody, Erbitux® and NIR laser with nanocomposites demonstrated the potential for selective bimodal cancer treatment by combination of EGFR-induced signaling inhibition as a systemic treatment and localized photothermal effects caused by the NIR laser.

Self-labeled magneto nanoprobes (SLMNs) were synthesized for one-step labeling of human mesenchymal stem cells (hMSCs) via non-invasive magnetic resonance (MR) image tracking. The surface of superparamagnetic nanocrystals (SMNCs) were enveloped by tri-aminated polysorbate 80 (TP80) not only for enhancement of the affinity for hMSCs, but also to achieve increased colloidal stability in the aqueous phase by the nanoemulsion method. The synthesized SLMNs exhibited excellent labeling efficiency of hMSCs and produced highly sensitive MR signals as well as safe cell cytotoxicity.

Fluorescent polycation-coated magnetic nanohybrids (FPMNs) were synthesized for the marking of human mesenchymal stem cells (hMSCs) and non-invasive tracking by both magnetic resonance (MR) and optical imaging. FPMNs were prepared by a polycation-based nanoemulsion method using magnetic nanocrystals (MNCs) as MR probes and polycationic polyethylenimine (PEI) which not only enhanced the affinity for hMSCs but also increased colloidal stability in the aqueous phase. Polycation-coated magnetic nanohybrids (PMNs) were further conjugated with a fluorescent dye (fluorescein isothiocyanate) to serve as optical imaging agents. FPMNs exhibited excellent colloidal stability and biocompatibility as well as high affinity for hMSCs. MR and optical images of hMSCs treated with FPMNs clearly demonstrated abundant potential as brilliant dual-mode imaging agents.

DOX–magnetic PLGA nanoparticles conjugated with well-tailored antibodies were synthesized for the detection and therapy of breast cancer. Magnetic nanocrystals embedded in polymeric nanoparticles did not inhibit the nanoparticle formulation or drug release kinetics. The multimodal nanoparticles demonstrated remarkable cancer cell affinity and ultrasensitivity via magnetic resonance imaging. Furthermore, the loaded anticancer drugs were released and sustained for three weeks.