Dumbbell-like upconversion nanoparticles synthesized by controlled epitaxial growth for light-heat-color tri-modal sensing of carcinoembryonic antigen.

Accurate quantitative analysis of tumor markers in a wide linear range has important practical significance towards complex clinical samples in cancer identification and monitoring of tumor development stages, but remains challenging. Herein, three-layer dumbbell-like upconversion nanoparticles NaErF4:Tm@NaYF4@NaNdF4 (labeled as UCNPs) combined with G-quadruplex (G4) DNAzyme are reported for tri-modal sensing of carcinoembryonic antigen (CEA) in a wide range using upconversion luminescence (UCL), photothermal and catalysis signal readouts. Initially, dumbbell-like UCNPs were controlled synthesized by a three-dimensional epitaxial growth strategy through tuning the concentration of Nd precursors. After surface functionalization, G4zyme-UCNPs-cDNA/Apt-MB was subsequently fabricated by biotin-streptavidin interaction and DNA hybridization. Quantitative detection of CEA was achieved by competitive interaction and magnetic separation, and the intensities of tri-modal signals (light, heat and catalysis-based chrominance) of dissociative probes are linearly related to the concentration of CEA. The results showed that the tri-modal sensing method exhibited a wide linear range (0.005-2000 ng/mL) and low limit of detection (LOD) across three models: the luminescence model (0.005-50 ng/mL, LOD = 0.910 pg/mL), the catalysis model (10-1000 ng/mL, LOD = 0.387 ng/mL), and the temperature model (50-2000 ng/mL, LOD = 1.114 ng/mL). These findings suggest that the tri-modal sensing platform is suitable for use in the analysis of a wide range of complex and diverse clinical samples.

Patch Based Grid Artifact Suppressing in Digital Mammography.

The mammography is the first choice of breast cancer screening, which has proven to be the most effective screening method. An antiscatter grid is usually employed to enhance the contrast of image by absorbing unexpected scattered signals. However, the grid pattern casts shadows and grid artifacts, which severely degrade the image quality. To solve the problem, we propose the patch based frequency signal filtering for fast grid artifacts suppressing. As opposed to whole image processing synchronously, the proposed method divides image into a number of blocks for tuning filter simultaneously, which reduces the frequency interference among image blocks and saves computation time by multithread processing. Moreover, for mitigating grid artifacts more precisely, characteristic peak detection is employed in each block automatically, which can accurately identify the location of the antiscatter grid and its motion pattern. Qualitative and quantitative studies were performed on simulation and real machine data to validate the proposed method. The results show great potential for fast suppressing grid artifacts and generating high quality of digital mammography.

Preparation of biocompatible aggregation-induced emission homopolymeric nanoparticles for cell imaging.

A series of new homopolymers with various degrees of polymerization derived from vinyl tetraphenylethene, that is, poly[2-(4-vinylphenyl)ethene-1,1,2-triyl)tribenzene] homopolymers, is synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The homopolymers exhibit a significant aggregation-induced emission (AIE) effect and an ability to assemble themselves into AIE polymer nanoparticles (NPs) during precipitation in a water/tetrahydrofuran (THF) mixture. The NPs also exhibit good dispersibility, stability, and biocompatibility. The AIE polymer NPs are used in imaging studies of HeLa cells.