Chemical doping with heteroatoms can effectively modulate physicochemical and photochemical properties of carbon dots (CDs). However, the development of multi heteroatoms codoped carbon nanodots is still in its early stage. In this work, a facile hydrothermal synthesis strategy was applied to synthesize multi heteroatoms (nitrogen and phosphorus) codoped carbon nanodots (N,P-CDs) using glucose as carbon source, and ammonia, phosphoric acid as dopant, respectively. Compared with CDs, the multi heteroatoms doped CDs resulted in dramatic improvement in the electronic characteristics and surface chemical activities. Therefore, the N,P-CDs prepared as described above exhibited a strong blue emission and a sensitive response to Fe(3+). The N,P-CDs based fluorescent sensor was then applied to sensitively determine Fe(3+) with a detection limit of 1.8 nM. Notably, the prepared N,P-CDs possessed negligible cytotoxicity, excellent biocompatibility, and high photostability. It was also applied for label-free detection of Fe(3+) in complex biological samples and the fluorescence imaging of intracellular Fe(3+), which indicated its potential applications in clinical diagnosis and other biologically related study.

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Aims/hypothesis Corneal confocal microscopy is a rapid non-invasive ophthalmic imaging technique that identifies peripheral and central neurodegenerative disease. Quantification of corneal sub-basal nerve plexus morphology, however, requires either time-consuming manual annotation or a less-sensitive automated image analysis approach. We aimed to develop and validate an artificial intelligence-based, deep learning algorithm for the quantification of nerve fibre properties relevant to the diagnosis of diabetic neuropathy and to compare it with a validated automated analysis program, ACCMetrics. Methods Our deep learning algorithm, which employs a convolutional neural network with data augmentation, was developed for the automated quantification of the corneal sub-basal nerve plexus for the diagnosis of diabetic neuropathy. The algorithm was trained using a high-end graphics processor unit on 1698 corneal confocal microscopy images; for external validation, it was further tested on 2137 images. The algorithm was developed to identify total nerve fibre length, branch points, tail points, number and length of nerve segments, and fractal numbers. Sensitivity analyses were undertaken to determine the AUC for ACCMetrics and our algorithm for the diagnosis of diabetic neuropathy. Uazman Alam and Yalin Zheng are joint senior authors.

Fluorescent carbon dots (CDs) originated from natural biomass have been of great interest in recent years because of their superior optical and chemical properties. However, previously reported CDs used only one natural biomass as precursor, and the fluorescence quantum yield (QY) and long-wavelength emissions are usually weak, which restrict their further applications in biology-relevant fields. Here a green method was demonstrated for the preparation of S and N codoped fluorescent CDs (S,N/CDs) by adopting two natural biomasses (water chestnut and onion) as precursors. The fabrication process is simple and environmentally friendly. By hydrothermal heating of water chestnut and onion, monodispersed, highly fluorescent S,N/CDs (diameter 3.5 nm) were obtained. The carboxyl on the surface of S,N/CDs can bind to Cu­(II) ion, resulting in the luminescence quenching of S,N/CDs. And coenzyme A (CoA) can restore the luminescence of S,N/CDs. Based on the above features of S,N/CDs, an innovative off–on fluorescence probe was presented for high sensitivity determination of CoA. Under optimum conditions, the linear range for CoA detection is 0.03–40 μM with a detection limit of 0.01 μM. The developed off–on nanoprobe was applied for the quantification of CoA in pig liver, and imaging of CoA in living T24 cells.

Low-dose total body irradiation (LTBI) is used in the treatment of some cancers mainly for immune enhancement rather than cell killing. However, the mechanism underlying LTBI remains unknown. In this study, by analyzing the immune patterns of lymphocytes, we found that the percentage and absolute number of CD4 1 CD25 1 Foxp3 1 regulatory T cells are markedly decreased in naive mice following treatment with LTBI. On the contrary, the CD4 1 CD44 1 /CD8 1 CD44 1 effector-memory T cells are greatly increased. Importantly, naive mice treated with dendritic cell-gp100 tumor vaccines under LTBI induced an enhancement of antigen-specific proliferation and cytotoxicity as well as interferon-c (IFN-c) secretion against F10 melanoma tumor challenge, compared to treatment with either the tumor vaccine or LTBI alone. Consequently, the treatment resulted in a reduced tumor burden and prolonged mouse survival. Our data demonstrate that LTBI's enhancement of antitumor immunity was mainly associated with selectively decreasing the proportion and number of T regulatory cells, implying the potential application of the combination of LTBI and a tumor vaccine in antitumor therapy.