Innovative phosphorus and nitrogen dual-doped hollow carbon dots (PNHCDs) have been fabricated for anticancer drug delivery and biological imaging. The functional groups of PNHCDs are introduced by simply mixing glucose, 1,2-ethylenediamine, and concentrated phosphoric acid. This is an automatic method without external heat treatment to rapidly produce large quantities of PNHCDs, which avoid high temperature, complicated operations, and long reaction times. The as-prepared PNHCDs possess small particle size, hollow structure, and abundant phosphate/hydroxyl/pyridinic/pyrrolic-like N groups, endowing PNHCDs with fluorescent properties, improving the accuracy of PNHCDs as an optical monitoring code both in vitro and in vivo. The investigation of PNHCDs as an anticancer drug nanocarrier for doxorubicin (DOX) indicates a better antitumor efficacy than free DOX owing to its enhanced nuclear delivery in vitro and tumor accumulation in vivo, which results in highly effective tumor growth inhibition and improved targeted therapy for cancer in clinical medicine.

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Well-defined magnetic separable, hollow spherical Fe 3 O 4 /TiO 2 hybrid photocatalysts were successfully prepared through a poly(styrene-acrylic acid) (PSA) template method. This bifunctional product was characterized in terms of the particle size, surface morphology, chemical composition, and magnetic properties using transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and X-ray powder diffraction (XRD) patterns. The M-H hysteresis loop for Fe 3 O 4 /TiO 2 hollow spheres indicates that the composite spheres show superparamagnetic characteristics at room temperature. These magnetic TiO 2 composites with hollow nature exhibit good photocatalytic activity under UV light irradiation and can be recycled six times by magnetic separation without major loss of activity. This method can be further applied to synthesize other bifunctional hollow spheres, such as Fe 3 O 4 /SnO 2 and Fe 3 O 4 /CdS.

One-step synthesis of carbon-encapsulated Fe(3)O(4) core/shell composites is reported. The Fe(3)O(4) cores were formed via the reduction of Fe(3+) by glucose under alkaline conditions obtained by the decomposition of urea. The amorphous carbon shells were carbonized from glucose. A possible formation mechanism for the Fe(3)O(4)@C composite was discussed. In order to characterize these Fe(3)O(4)@C core-shell composites, high-resolution transmission electron microscopy (HR-TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS) and a superconducting quantum interference device (SQUID) magnetometer were employed to characterize the sample obtained using the above method.

Activating room-temperature phosphorescence (RTP) emission in aqueous environments is a challenging feat because of the releasing of nonradiative decay pathways. Here, a design strategy was presented that effectively promotes the presence of RTP of carbon dots (CDs) in aqueous solutions by utilizing CDs and melamine to construct hydrogen-bonded networks to form a polymer (M-CDs). The obtained M-CDs not only enjoy an ultralong phosphorescence lifetime of 664 ms, but also relatively high quantum yield of 25% in an aqueous environment at 468 nm excitation. This is also a rare example of achieving RTP of CDs with a solid state in an aqueous environment. Further investigations reveal that the hydrogen-bonded networks are critical to the implementation of RTP in an aqueous environment. The existence of covalent bonds in CDs and melamine further stabilizes the hydrogen-bond skeleton and triplet state. Furthermore, the bound water formed inside the M-CDs also plays an indispensable role in stabilizing the RTP in the aqueous solution. Given the feature, the M-CDs are used to effectively implement double data encryption and decryption. In addition, this strategy is universal for most phosphorescence materials. This result will pave the way toward expanding RTP materials and their applications in aqueous environments.

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An as-synthesised hollow carbon nanoparticle (HC-NP) sample has been proved to be a relatively complex mixture, and its complexity can be reduced significantly by high-performance liquid chromatography. An unprecedented reduction in such complexity can reveal fractions of HC-NP with unique luminescence properties. While the UV-vis absorption profile for the HC-NP mixture is featureless, the HC-NP fractions do possess unique absorption bands and specific emission wavelengths. The HC-NP fractions are fully anatomised by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry, displaying their fragmentation mass ion features. The shell thickness and crystal lattices of the selected HC-NP fractions are determined as 6.13, 8.31, 2.22, and 8.66 nm, and 0.37, 0.35, 0.33, and 0.32 nm by transmission electron microscopy, respectively. The fractionated HC-NP show profound differences in emission quantum yield, allowing for brighter HC-NP to be isolated from an apparent low quantum yield mixture. Finally, red, green and blue emissive HC-NP are isolated from the as-synthesised HC-NP sample. They show good photostability and have been demonstrated to be excellent probes for cellular imaging.

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