Hao-Yan Yin

Precise Labeling and Tracking of Lipid Droplets in Adipocytes Using a Luminescent ZnSalen Complex

Designing two-photon probes for precise labeling of lipid droplets (LDs) and monitoring LD dynamics in adipocytes is of great significance to understand LD homeostasis. We herein report that a luminescent metal complex LD-TPZn can specifically image LDs in adipose cells and tissue using one- or two-photon fluorescence microscopy. Importantly, LD-TPZn exhibited higher specificity to LDs than the commercial dyes Nile Red and Bodipy 493/503, probably due to different cellular uptake pathways, that is, clathrin-mediated endocytosis and non-selectively passive diffusion, respectively. More importantly, LD-TPZn can be applied as a two-photon LD probe to image adipose tissue, one of the most challengeable tissues for traditional one-photon fluorescence microscope imaging due to the strong light scattering. Most importantly, LD-TPZn can be used to monitor LD growth during adipogenesis of preadipocytes, which is highly desirable to unravel the relationship between LD homeostasis and metabolic diseases.

Multiplexed Detection of Attomoles of Nucleic Acids Using Fluorescent Nanoparticle Counting Platform

The sensitive multiplexed detection of nucleic acids in a single sample by a simple manner is of pivotal importance for the diagnosis and therapy of human diseases. Herein, we constructed an automatic fluorescent nanoparticle (FNP) counting platform with a common fluorescence microscopic imaging setup for nonamplification multiplexed detection of attomoles of nucleic acids. Taking the advantages of the highly bright, multicolor emitting FNPs and magnetic separation, the platform enables sensitive multiplexed detection without the need for extra fluorescent labels. Quantification for multiplex DNAs, multiplex microRNAs (miRNA), as well as a DNA and miRNA mixture was achieved with a similar dynamic range, a limit of detection down to 5 amol (5 μL detection volume), and a 81-115% spike recovery from different biological sample matrices. In particular, the sensitivity for multiplex miRNA is by far among the highest without using amplification or the lock nucleic acid hybridization enhancement strategy. Results regarding miRNA-141 from four different cell lines were agreeable with those of the quantitative reverse transcription polymerase chain reaction. Simultaneous detection of miRNA-141 and miRNA-21 in four different cell lines yielded consistent results with publications, indicating the potential for monitoring multiplex miRNA expression associated with the collaborative regulation of important cellular events. This work expands the rule set of multiplex nucleic acid detection strategies and shows promising potential application in clinical diagnosis.

Luminescent Zinc Complexes as Bioprobes for Imaging Molecular Events in Live Cells

Abstract Design of luminescent metal complexes for imaging intracellular molecular events is of importance to expand the scope of biological application of inorganic complexes. In this chapter, we particularly focus on a variety of applications that are offered by d10 metal zinc(II) complexes, which is a bioavailable metal that widely exists in metalloenzymes and has a closed-shell electronic configuration anticipated to produce fluorescence characteristics dependent on the ligand. Starting from a comprehensive overview of the relationship between the basic structural characteristics and biological activity, we highlight typical zinc(II) complexes as biological imaging probes for visualization of particular molecular events in live cells.

Lutetium(III) porphyrinoids as effective triplet photosensitizers for photon upconversion based on triplet-triplet annihilation (TTA)

We described the first application of lanthanide complexes of porphyrinoids, exemplified by lutetium (Lu), as efficient photosensitizers in photon upconversion (UC) based on triplet–triplet annihilation (TTA). Compared to the widely used d block metals, Lu(III) porphyrinoids exhibit a better sensitization ability in photon UC based on TTA (TTA-UC), which is ascribed to the extra-long triplet lifetime compared with the d block metal counterparts, using 9,10-bis(2-phenylethynyl)anthracene (BPEA) or rubrene as an acceptor. Notably, the Lu(III) complex of the porphyrin (Lu-1)/BPEA pair showed a high upconversion efficiency of 12.4% in degassed toluene. Importantly, to demonstrate the potential application of Lu porphyrinates in TTA-UC based bioimaging, we prepared nanomicelles and mesoporous silica nanoparticles with Lu-1/BPEA or Lu(III) porpholactone (Lu-2)/BPEA pairs. In living cell imaging, the capability of Lu-1 or Lu-2 as a TTA-UC sensitizer has been observed, displaying their potential application in biological studies. This work enriches the repertoire of metal sensitizers in TTA-UC with the capability of living cell imaging and, more importantly, also extends the scope of lanthanide coordination chemistry to lanthanide chemical biology related to biological optical materials and medicine.