Coauthored Publications with: Lee

Journal Article

Dhenadhayalan, N, Lee H-L, Yadav K, Lin K-C, Lin Y-T, Chang AHH.  2016.  Silicon Quantum Dot-Based Fluorescence Turn-On Metal Ion Sensors in Live Cells. ACS Applied Materials and Interfaces. 8:23953-23962., Number 36 AbstractWebsite

Multiple sensor systems are designed by varying aza-crown ether moiety in silicon quantum dots (SiQDs) for detecting individual Mg2+, Ca2+, and Mn2+ metal ions with significant selectivity and sensitivity. The detection limit of Mg2+, Ca2+, and Mn2+ can reach 1.81, 3.15, and 0.47 μM, respectively. Upon excitation of the SiQDs which are coordinated with aza-crown ethers, the photoinduced electron transfer (PET) takes place from aza-crown ether moiety to the valence band of SiQDs core such that the reduced probability of electron-hole recombination may diminish the subsequent fluorescence. The fluorescence suppression caused by such PET effect will be relieved after selective metal ion is added. The charge-electron binding force between the metal ion and aza-crown ether hinders the PET and thereby restores the fluorescence of SiQDs. The design of sensor system is based on the fluorescence "turn-on" of SiQDs while in search of the appropriate metal ion. For practical application, the sensing capabilities of metal ions in the live cells are performed and the confocal image results reveal their promising applicability as an effective and nontoxic metal ion sensor. © 2016 American Chemical Society.
Lin, T-W, Dhenadhayalan N, Lee H-L, Lin Y-T, Lin K-C, Chang AHH.  2019.  Fluorescence turn-on chemosensors based on surface-functionalized MoS2 quantum dots. Sensors and Actuators, B: Chemical. 281:659-669. AbstractWebsite

The multiple sensing capabilities of molybdenum disulfide quantum dots (MoS2 QDs) towards metal ions were scrutinized by tuning their surface functional groups. The MoS2 QDs surface was individually modified with thiol-containing capping agents to form carboxylic-, amine- and thiol-functionalized MoS2 QDs (MoS2/COOH, MoS2/NH2 and MoS2/SH) by the facile hydrothermal method. Each as-prepared QDs exhibits strong excitation wavelength dependent fluorescence behavior. The design of MoS2 QDs based metal ion sensor was implemented based on the fluorescence turn-on mechanism. These MoS2/COOH, MoS2/NH2 and MoS2/SH QDs sensors exhibit superior performance towards the highly selective detection of Co2+, Cd2+ and Pb2+ ions, respectively, due to the varied association of each functional group towards metal ions. The resultant detection limit of Co2+, Cd2+ and Pb2+ was evaluated to be 54.5, 99.6 and 0.84 nM, respectively, and the related fluorescence turn-on mechanism is verified unambiguously. The binding energies were calculated for QDs with metal ions pairs and the results lent support to the determined sensitivity. The as-prepared QDs were also successfully demonstrated to detect the above metal ions in real water samples. While becoming potential candidates in the chemosensors based on the fluorescence probe, these surface modified MoS2 QDs can offer an excellent sensing capability for specific metal ions with extremely high selectivity.

Lee, T.-Y., JTLCVSTPK.  2020.  Carbon dot nanoparticles exert inhibitory effects on human platelets and reduce mortality in mice with acute pulmonary thromboembolism. AbstractWebsite

The inhibition of platelet activation is considered a potential therapeutic strategy for the treatment of arterial thrombotic diseases; therefore, maintaining platelets in their inactive state has garnered much attention. In recent years, nanoparticles have emerged as important players in modern medicine, but potential interactions between them and platelets remain to be extensively investigated. Herein, we synthesized a new type of carbon dot (CDOT) nanoparticle and investigated its potential as a new antiplatelet agent. This nanoparticle exerted a potent inhibitory effect in collagen-stimulated human platelet aggregation. Further, it did not induce cytotoxic effects, as evidenced in a lactate dehydrogenase assay, and inhibited collagen-activated protein kinase C (PKC) activation and Akt (protein kinase B), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) phosphorylation. The bleeding time, a major side-effect of using antiplatelet agents, was unaffected in CDOT-treated mice. Moreover, our CDOT could reduce mortality in mice with ADP-induced acute pulmonary thromboembolism. Overall, CDOT is effective against platelet activation in vitro via reduction of the phospholipase C/PKC cascade, consequently suppressing the activation of MAPK. Accordingly, this study affords the validation that CDOT has the potential to serve as a therapeutic agent for the treatment of arterial thromboembolic disorders. © 2020 by the authors.
Chang, Y-P, Tsai P-Y, Lee H-L, Lin K-C.  2013.  Interfacial electron transfer from CdSe/ZnS quantum dots to TiO2 nanoparticles: Linker dependence at single molecule level. Electroanalysis. 25:1064-1073., Number 4 AbstractWebsite

We utilize single molecule spectroscopy combined with time-correlated single-photon counting to probe electron transfer (ET) kinetics from CdSe/ZnS (core/shell) quantum dots (QDs) to TiO2 through various lengths of linker molecules. The QD-linker-TiO2 complexes with varied linker length, linker structure, and QD size are fabricated by a surface-based stepwise method to show control of the rate and of the magnitude of fluctuations of photo-induced ET at the single molecule level. The ET rate constants are determined to be 2.8×107, 1.9×107, and 3.5×106s-1 for the chain length of 1.5, 6.2 and 13.8Å, respectively. The electronic coupling strengths between QDs and TiO2 are further calculated to be 3.68, 3.60, and 1.59cm-1 for the three different chain lengths by using the Marcus ET model. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Lee, H-L, Dhenadhayalan N, Lin K-C.  2015.  Metal ion induced fluorescence resonance energy transfer between crown ether functionalized quantum dots and rhodamine B: Selectivity of K+ ion. RSC Advances. 5:4926-4933., Number 7 AbstractWebsite

We report a ratiometric fluorescent metal ion sensor based on the mechanism of fluorescence resonance energy transfer (FRET) between synthesized 15-crown-5-ether capped CdSe/ZnS quantum dots (QDCE) and 15-crown-5-ether attached rhodamine B (RBCE) in pH 8.3 buffer solution. Fluorescence titration with different metal ions in pH 8.3 buffer solution of the QDCE-RBCE conjugate showed a decrease and an increase in the fluorescence intensity for QDCE and RBCE moieties respectively due to FRET from QDCE to RBCE. This sensor system shows excellent selectivity towards K+ ions resulting in increasing efficiency of FRET. Energy transfer efficiency depends on the affinity between metal ions and crown ether functionalized with QDCE/RBCE. The detailed analysis of FRET was explored. This water soluble ratiometric sensor system can act as a good FRET probe for sensing applications especially in biological systems. © The Royal Society of Chemistry 2015.
Chao, M-H, Lin Y-T, Dhenadhayalan N, Lee H-L, Lee H-Y, Lin K-C.  2017.  3D Probed Lipid Dynamics in Small Unilamellar Vesicles. Small. 13, Number 13 AbstractWebsite

Single-molecule fluorescence correlation spectroscopy overcomes the resolution barrier of optical microscopy (10≈–20 nm) and is utilized to look into lipid dynamics in small unilamellar vesicles (SUVs; diameter < 100 nm). The fluorescence trajectories of lipid-like tracer 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindodicarbocyanine (DiD) in the membrane bilayers are acquired at a single-molecule level. The autocorrelation analysis yields the kinetic information on lipid organization, oxygen transport, and lateral diffusion in SUVs' membrane. First, the isomerization feasibility may be restricted by the addition of cholesterols, which form structure conjugation with DiD chromophore. Second, the oxygen transport is prevented from the ultrasmall cluster and cholesterol-rich regions, whereas it can pass through the membrane region with liquid-disordered phase (Ld) and defects. Third, by analyzing 2D spectra correlating the lipid diffusion coefficient and triplet-state lifetime, the heterogeneity in lipid bilayer can be precisely visualized such as lipid domain with different phases, the defects of lipid packing, and DiD-induced “bouquet” ultrasmall clusters. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Dhenadhayalan, N, Yadav K, Sriram MI, Lee H-L, Lin K-C.  2017.  Ultra-sensitive DNA sensing of a prostate-specific antigen based on 2D nanosheets in live cells. Nanoscale. 9:12087-12095., Number 33 AbstractWebsite

Herein, we report ultra-sensitive sensing of a prostate-specific antigen (PSA), which is used as a biomarker to detect prostate cancer, using a molybdenum series (MoO3, MoS2, and MoSe2) of two-dimensional nanosheets (2D NSs). Moreover, the design of a 2D NS-based PSA aptamer sensor system was demonstrated based on a fluorescence turn-on mechanism in the presence of a target. The 2D NSs acted as an excellent sensing platform in which the PSA aptamer was adsorbed on the NSs and subsequent energy transfer between them led to fluorescence quenching of the aptamer. The detection limit of PSA was achieved to be 13 pM for MoO3 NSs, whereas the MoS2 and MoSe2 systems exhibited a detection limit of 72 and 157 pM, respectively. To the best of our knowledge, this is the first report on the ultra-sensitive detection of a 2D NS-based aptamer sensor. The in vitro bioimaging measurements were performed using confocal fluorescence microscopy. Herein, PSA detection was successfully demonstrated in human embryonic kidney 293T (HEK) live cells. Moreover, the MoO3, MoS2, and MoSe2 NSs exhibit excellent biocompatibility and low toxicity; thus, these 2D NSs can be used as a promising sensor platform to detect prostate cancer. This journal is © The Royal Society of Chemistry.