Plasmonic Nanosensors: Review and Prospect

Inhee Choi,Yeonho Choi IEEE 2012 IEEE journal on selected topics in quantum electro Vol.18 No.3

<P>Recent progress in plasmon-based sensors has greatly overcome the limitations of conventional optical sensors, in terms of sensitivity, tunability, photostability, and in vivo applicability, by employing nanostructured materials. In this review, we summarize three types of plasmon-based nanosensors categorized by the geometries of sensing platforms as plasmonic transducers, which are planar nanofilm, periodic nanoarrays, and individual nanoparticles, respectively. We then introduce the notable accomplishments to enhance the sensing performances for each sensing platform. Additionally, we present recent works for signal enhancement strategy based on the targeted nanoassemblies of particles, which can be applied to all plasmon-based sensing platforms. The focus of this review will be on how plasmonic nanostructures can be applied to detect biological and chemical analytes, and notable approaches to improve the sensitivity.</P>

Bayesian Model for the Classification of GPCR Agonists and Antagonists

Inhee Choi,Hanjo Kim,Jihoon Jung,남기엽,유성은,강남숙,노경태 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.8

G-protein coupled receptors (GPCRs) are involved in a wide variety of physiological processes and are known to be targets for nearly 50% of drugs. The various functions of GPCRs are affected by their cognate ligands which are mainly classified as agonists and antagonists. The purpose of this study is to develop a Bayesian classification model,that can predict a compound as either human GPCR agonist or antagonist. Total 6627 compounds experimentally determined as either GPCR agonists or antagonists covering all the classes of GPCRs were gathered to comprise the dataset. This model distinguishes GPCR agonists from GPCR antagonists by using chemical fingerprint, FCFP_6. The model revealed distinctive structural characteristics between agonistic and antagonistic compounds: in general, 1)GPCR agonists were flexible and had aliphatic amines, and 2) GPCR antagonists had planar groups and aromatic amines. This model showed very good discriminative ability in general, with pretty good discriminant statistics for the training set (accuracy: 90.1%) and a good predictive ability for the test set (accuracy: 89.2%). Also, receiver operating characteristic (ROC) plot showed the area under the curve (AUC) to be 0.957, and Matthew’s Correlation Coefficient (MCC) value was 0.803. The quality of our model suggests that it could aid to classify the compounds as either GPCR agonists or antagonists, especially in the early stages of the drug discovery process.

Gold and silver plasmonic nanoprobes trace the positions of histone codes

( Inhee Choi ),( Jihwan Song ),( Hyunsung Park ) 생화학분자생물학회 2022 BMB Reports Vol.55 No.3

We visualized the distribution of heterochromatin in a single nucleus using plasmonic nanoparticle-conjugated H3K9me3 and H3K27me3 antibodies. Due to distance-dependent plasmonic coupling effects between nanoprobes, their scattering spectra shift to longer wavelengths as the distance between heterochromatin histone markers reduced during oncogene-induced senescence (OIS). These observations were supported by simulating scattering profiles based on considerations of particle numbers, interparticle distances, and the spatial arrangements of plasmonic nanoprobes. Using this plasmon-based colourimetric imaging, we estimated changes in distances between H3K9me3 and H3K27me3 during the formation of senescence-associated heterochromatin foci in OIS cells. We anticipate that the devised analytical technique combined with high-spatial imaging and spectral simulation will eventually lead to a new means of diagnosing and monitoring disease progression and cellular senescence. [BMB Reports: Perspective 2022; 55(3): 111-112]

Mitochondrial abnormalities related to the dysfunction of circulating endothelial colony-forming cells in moyamoya disease

Choi, Jung Won,Son, Sung Min,Mook-Jung, Inhee,Moon, Youn Joo,Lee, Ji Yeoun,Wang, Kyu-Chang,Kang, Hyun-Seung,Phi, Ji Hoon,Choi, Seung Ah,Chong, Sangjoon,Byun, Jayoung,Kim, Seung-Ki Journal of Neurosurgery Publishing Group 2018 Journal of neurosurgery Vol.129 No.5

<B>OBJECTIVE</B><P>Moyamoya disease (MMD) is a unique cerebrovascular disorder characterized by the progressive occlusion of the bilateral internal carotid arteries. Endothelial colony-forming cells (ECFCs), previously termed “endothelial progenitor cells,” play an important role in the pathogenesis of MMD. In this study, the authors performed morphological and functional studies of the mitochondria of ECFCs from patients with MMD to present new insights into the pathogenesis of the disease.</P><B>METHODS</B><P>The morphology of ECFCs from 5 MMD patients and 5 healthy controls was examined under both a transmission electron microscope and a confocal laser scanning microscope. The oxygen consumption rates (OCRs), mitochondrial membrane potentials (MMPs), intracellular Ca<SUP>2+</SUP> concentrations, mitochondrial enzyme activities, and reactive oxygen species (ROS) levels were measured. Functional activity of the ECFCs was evaluated using a capillary tube formation assay.</P><B>RESULTS</B><P>The ECFCs from the MMD patients displayed a disrupted mitochondrial morphology, including a shorter and more circular shape. The ECFC mitochondria from the MMD patients exhibited functional abnormalities, which were assessed as a decreased OCR and an increased intracellular Ca<SUP>2+</SUP> concentration. Moreover, the ECFCs from MMD patients showed increased ROS levels. Interestingly, treatment with an ROS scavenger not only reversed the mitochondrial abnormalities but also restored the angiogenic activity of the ECFCs from the MMD patients.</P><B>CONCLUSIONS</B><P>The mitochondria of ECFCs from MMD patients, as compared with those from healthy patients, exhibited morphological and functional abnormalities. This finding suggests that the mitochondrial abnormalities may have a role in the pathogenesis of MMD.</P>

Binding Mode Analysis of Topoisomerase Inhibitors, 6-Arylamino-7-chloro-quinazoline-5,8-diones, within the Cleavable Complex of Human Topoisomerase I and DNA

Inhee Choi,Choonmi Kim,최선 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12

A series of 6-arylamino-7-chloro-quinazoline-5,8-diones have been evaluated as novel human topoisomerase I (TOP1) inhibitors based on the antitumor activity of 1,4-naphthoquinone. Besides their in vitro cytotoxicity, their ability to inhibit human TOP1-DNA in vitro was tested with human TOP1 and a supercoiled (Form I) plasmid substrate DNA (Park et al., 2004). Using the flexible docking program, QXP, we have developed ternary complex models by docking camptothecin and ten 6-arylamino-7-chloro-quinazoline-5,8-dione analogs into the X-ray crystal structure of the human TOP1-DNA binary complex. The compound binding modes substantiated their potential inhibitory activities against TOP1 in the relaxation assay. Compounds whose templates the 6-arylamino-7-chloro-quinazoline-5,8-dione moiety intercalated between the -1 and +1 base pairs of the scissile strand showed good inhibitory activities. The template of compounds with poor inhibitory activities intercalated between the DNA base pairs of the nonscissile strand. The interaction of the compounds and the human TOP1-DNA binary complex were stabilized by an array of hydrogen bonds and hydrophobic interactions with the TOP1 residues, DNA bases, and water molecules. Docking results from the QXP program suggested potential binding modes of each non-CPT type compound in the human TOP1-DNA cleavable complex, which could provide a rational basis for future TOP1 inhibitor development.

Spontaneous Self-Formation of 3D Plasmonic Optical Structures

Choi, Inhee,Shin, Yonghee,Song, Jihwan,Hong, SoonGweon,Park, Younggeun,Kim, Dongchoul,Kang, Taewook,Lee, Luke P. American Chemical Society 2016 ACS NANO Vol.10 No.8

<P>Self-formation of colloidal oil droplets in water or water droplets in oil not only has been regarded as fascinating fundamental science but also has been utilized in an enormous number of applications in everyday life. However, the creation of three-dimensional (3D) architectures by a liquid droplet and an immiscible liquid interface has been less investigated than other applications. Here, we report interfacial energy-driven spontaneous self-formation of a 3D plasmonic optical structure at room temperature without an external force. Based on the densities and interfacial energies of two liquids, we simulated the spontaneous formation of a plasmonic optical structure when a water droplet containing metal ions meets an immiscible liquid polydimethylsiloxane (PDMS) interface. At the interface, the metal ions in the droplet are automatically reduced to form an interfacial plasmonic layer as the liquid PDMS cures. The self-formation of both an optical cavity and integrated plasmonic nanostructure significantly enhances the fluorescence by a magnitude of 1000. Our findings will have a huge impact on the development of various photonic and plasmonic materials as well as metamaterials and devices.</P>

Plasmonic Nanosensors for Bio / Chemical Sensing Applications

Inhee Choi 한국고분자학회 2012 한국고분자학회 학술대회 연구논문 초록집 Vol.2012 No.4

Colorimetric tracking of protein structural evolution based on the distance-dependent light scattering of embedded gold nanoparticles

Choi, Inhee,Yang, Young In,Jeong, Eunhye,Kim, Kihoon,Hong, Surin,Kang, Taewook,Yi, Jongheop The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.17

<P>In this communication, we describe a new, simplified colorimetric method for <I>in situ</I> tracking of structural evolution of Cu/Zn-superoxide dismutase (SOD1) aggregates, based on changes in plasmonic coupling between gold nanoparticles (GNPs) embedded along the structural backbone of the SOD1 aggregates.</P> <P>Graphic Abstract</P><P>A new, simplified colorimetric method for tracking of structural evolution of protein aggregate, based on changes in plasmonic coupling between gold nanoparticles embedded along the structural backbone of the aggregate, was demonstrated. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc17174k'> </P>

Core-Satellites Assembly of Silver Nanoparticles on a Single Gold Nanoparticle via Metal Ion-Mediated Complex

Choi, Inhee,Song, Hyeon Don,Lee, Suseung,Yang, Young In,Kang, Taewook,Yi, Jongheop American Chemical Society 2012 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.134 No.29

Size-selective concentration and label-free characterization of protein aggregates using a Raman active nanofluidic device

Choi, Inhee,Huh, Yun Suk,Erickson, David Royal Society of Chemistry 2011 Lab on a chip Vol.11 No.4

<P>Trace detection and physicochemical characterization of protein aggregates have a large impact in understanding and diagnosing many diseases, such as ageing-related neurodegeneration and systemic amyloidosis, for which the formation of protein aggregates is one of the pathological hallmarks. Here we demonstrate an innovative label-free method for detecting and characterizing small amounts of early stage protein aggregates using a Raman active nanofluidic device. Sub-micrometre channels formed by a novel elastomeric collapse technique enable the separation and concentration of matured protein aggregates from small protein molecules. The Raman enhancement by gold nanoparticle clusters fixed below a micro/nanofluidic junction allows characterization of intrinsic properties of protein aggregates at concentration levels (∼fM) much lower than can be done with traditional analytical tools. With our device we show for the first time the concentration dependence of protein aggregation over these low concentration ranges. We expect that our method could facilitate definitive diagnosis and possible therapeutics of diseases at early stages.</P> <P>Graphic Abstract</P><P>We demonstrate an innovative label-free method for detecting and characterizing trace amounts of early stage protein aggregates. Nanofluidic channels formed by a novel elastomeric collapse technique enable the separation and concentration of matured protein aggregates. The Raman enhancement by gold nanoparticle clusters fixed below a micro/nanofluidic junction allows for characterizing intrinsic properties of protein aggregates. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0lc00383b'> </P>