Publications by authors named "Chung Yan Poon"

Objectives: To compare the associations of COVID-19 preventive behaviours and depressive and anxiety symptoms with eHealth literacy and COVID-19 knowledge among Korean adults.

Design: A cross-sectional online survey was conducted in April 2020.

Setting: Seoul metropolitan area in South Korea.

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Background: Xanthohumol has been reported to have cytoprotection through activation of Nrf2-ARE signaling pathway and; it has capability of scavenging free radicals, suggesting its potential for the prevention of neurodegeneration. However, the bio-incompatibility and blood-brain barrier impermeability of xanthohumol hindered its in vivo efficacy potential for treating Alzheimer's disease (AD).

Objective: We designed and prepared a series of xanthohumol derivatives to enhance the desirable physical, biological and pharmacological properties in particular the blood-brain barrier permeability for intervention of AD.

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Lysosomes are organelles containing many hydrolytic enzymes responsible for degrading macromolecules. Abnormal lysosomal pH changes are known to associate with dysfunction of cells linking to various diseases such as cancer and neurodegenerative disorders. Thus, it is of paramount importance to monitor lysosomal pH changes in order to investigate the pathological conditions.

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We report herein an investigation of carbazole-based cyanine, ()-4-(2-(9-(2-(2-methoxyethoxy)ethyl)-9-carbazol-3-yl)-vinyl)-1-methyl-quinolin-1-iumiodide (SLM), as an effective theranostic agent for Alzheimer's disease (AD). This cyanine exhibited desirable multifunctional and biological properties, including amyloid-β (Aβ)-oligomerization inhibition, blood-brain barrier permeability, low neurotoxicity, neuroprotective effect against Aβ-induced toxicities, high selectivity and strong binding interactions with Aβ peptide/species, good biostability, as well as strong fluorescence enhancement upon binding to Aβ species for diagnosis and therapy of AD. This cyanine has been successfully applied to perform near-infrared in vivo imaging of Aβ species in transgenic AD mouse model.

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Acid-base disorders disrupt proper cellular functions, which are associated with diverse diseases. Development of highly sensitive pH probes being capable of detecting and monitoring the minor changes of pH environment in living systems is of considerable interest to diagnose disease as well as investigate biochemical processes in vivo. We report herein two novel high-resolution ratiometric two-photon (TP) fluorescent probes, namely, PSIOH and PSIBOH derived from carbazole-oxazolidine π-conjugated system for effective sensing and monitoring acid pH in a biological system.

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Senile plaques, the extracellular deposit of amyloid-β (Aβ) peptides, are one of the neuropathological hallmarks found in Alzheimer's disease (AD) brain. The current method of brain imaging of amyloid plaques based on positron emission tomography (PET) is expensive and invasive with low spatial resolution. Thus, the development of sensitive and nonradiative amyloid-β (Aβ)-specific contrast agents is highly important and beneficial to achieve early AD detection, monitor the disease progression, and evaluate the effectiveness of potential AD drugs.

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Alzheimer's disease (AD) is the most prevalent but still incurable neurodegenerative form of dementia. Early diagnosis and intervention are crucial for delaying the onset and progression of the disease. We herein report a novel fluoro-substituted cyanine, F-SLOH, which exhibits good Aβ oligomer selectivity with a high binding affinity, attributed to the synergistic effect of strong π-π stacking and intermolecular CH···O and CH···F interactions.

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In this work, we developed a simple yet robust single particle scattering intensity measurement method for the quantification of cancer-related biomarkers. The design is based on the plasmonic coupling effect between noble metal nanoparticles. First, the primary and secondary antibodies were conjugated onto the surface of 60 nm gold nanoparticles (AuNPs, act as capture probes) and 50 nm silver nanoparticles (AgNPs, act as signal amplification probes) respectively.

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A versatile nanoprobe was developed for trypsin quantification with fluorescence resonance energy transfer (FRET). Here, fluorescence graphene quantum dot is utilized as a donor while a well-designed coumarin derivative, CMR2, as an acceptor. Moreover, bovine serum albumin (BSA), as a protein model, is not only served as a linker for the FRET pair, but also a fluorescence enhancer of the quantum dots and CMR2.

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Being one of the hallmarks of Alzheimer's disease, β-amyloid (Aβ) aggregates induce complicated neurotoxicity. Evidences show that the underlying mechanism of neurotoxicity involves a glutamate receptor subtype, N-methyl-D-aspartate (NMDA) receptor, an increase in intracellular calcium(II) ion loading as well as an elevation in oxidation stress. In this work, among the 35 chemical components of Chinese herbal medicines (CHMs) being screened for inhibitors of Aβ aggregation, four of them, namely albiflorin, aloeemodin, neohesperidin and physcion, were found for the first time to exhibit a potent inhibitory effect on Aβ(1-40) and Aβ(1-42) aggregation.

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