It is challenging and urgent in neurosurgery to improve therapeutic effect of the most common and lethal malignant glioma in central nervous system. The superadditive therapeutic effect of photothermal therapy and photodynamic therapy holds great promise. Herein, a highly efficient photothermal-photodynamic therapy nanoplatform was developed on the basis of Fe 3 O 4 -IR806 superparticles. The introduction of the near-infrared (NIR) dye IR806 and the fabrication of the self-assembled structure of the superparticles warrant 3.5 times increase in the photothermal conversion efficiency compared with the Fe 3 O 4 nanoparticles . The Fe 3 O 4 -IR806 superparticles generated reactive oxygen species (ROS) with the NIR light irradiation by virtue of the dye IR806. Both in vitro and in vivo experiments demonstrated that the Fe 3 O 4 -IR806 superparticles exhibited negligible toxicity. The Fe 3 O 4 -IR806 superparticles efficiently inhibited the cultured glioma cells via photothermal ablation and ROS cytotoxicity in vitro, as well as suppressed the bearing glioma growth in vivo with the NIR light induction. Our results highlight the promise of the Fe 3 O 4 -IR806 superparticles for improved photothermal-photodynamic therapy of cancer.
A reliable, rapid and ultrasensitive immunoassay is described for determination of immunoglobulin G (IgG). It is making use of biofunctional magnetite (Fe 3 O 4 ) superparticles coated with SiO 2 and serving as an infrared (IR) probe. The unique IR fingerprint signals originating from the transverse and longitudinal phonon modes, respectively, of the asymmetric stretching of the Si–O–Si bridges display a satisfactory resistance to optical interference from the environment. The adoption of Fe 3 O 4 superparticles instead of Fe 3 O 4 nanoparticles as the magnetic core warrants a controllable structure and a strong magnetic response. This facilitates the efficient purification of the probes and the alleviation of the interfacial resistance between the liquid-solid interfaces by using a magnet. The gold-coated substrate was used to immobilize goat-anti-human IgG. The analyte (human IgG) was incubated with the IR probes, and then captured by the substrate immobilized antibody with the assistance of an external magnetic field. The integral area of the IR absorption band between 1250 cm −1 – 900 cm −1 was chosen for quantitative assay. The limit of detection is 95 fM, which is two orders of magnitude better than that without the magnetic field. The assay time was shortened from 2 h to 1 min. High selectivity, specificity, and long-term stability of the immunoassay were achieved. The performance of the assay when analyzing blood samples confirmed the practicability of the method.
Schematic presentation of the infrared (IR) immunoassay based on Fe 3 O 4 superparticle@SiO 2 nanocomposites. The assistance of an external magnetic field reduces the incubation time and improves the detection sensitivity.
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