Highly sensitive and selective in vitro diagnostics based on DNA probes and aptamers

Hunho Jo,Seonghwan Lee,Changill Ban 한국구조생물학회 2015 Biodesign Vol.3 No.1

Medical diagnosis is very important and essential for maintaining a healthy life. In vitro diagnostics have recently been a focus of scientists and researchers because they have a number of merits over other diagnostic methods. In particular, nucleic acid-based diagnostic methods are powerful and promising techniques. In this review, various types of nucleic acid-based in vitro diagnostics are introduced. These methods can be categorized into three groups according to their analytical approaches. In addition, aptamer-based diagnostic methods are covered in greater detail because aptamers are promising materials for diverse areas, not only as alternatives to antibodies but also as the core components of analytical equipment. It is expected that in vitro diagnostics based on DNA probes and aptamers will become a valuable platform encompassing all types of diseases.

Enzyme-linked antibody aptamer assays based colorimetric detection of soluble fraction of activated leukocyte cell adhesion molecule

Her, Jin,Jo, Hunho,Ban, Changill Elsevier 2017 Sensors and actuators. B Chemical Vol.242 No.-

<P><B>Abstract</B></P> <P>Patients with pancreatic and colorectal cancers have elevated levels of activated leukocyte cell adhesion molecule (ALCAM) in their blood compared to healthy individuals. To this end, sensitive detection of soluble fraction of ALCAM (sALCAM), also called CD166, was performed using enzyme-linked antibody aptamer (ELAA) assay. For the assay, aptamer specific for sALCAM was used as a capturing probe and polyclonal antibody modified with an enzyme was used as a detecting probe for colorimetric visualization. The ELAA assay was able to detect sALCAM as low as 0.31ng/mL. In addition, the assay enabled the differentiation of sALCAM from other proteins in buffer as well as in human serum. The ELAA assay provides cost-effective, highly sensitive, and reproducible detection of sALCAM.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Schemes of enzyme-linked antibody aptamer assays are proposed. </LI> <LI> The enzyme-linked antibody aptamer assay was able to successfully differentiate sALCAM among other proteins. </LI> <LI> The enzyme-linked antibody aptamer assay presents an alternative way of detecting sALCAM. </LI> </UL> </P>

Ultra-effective photothermal therapy for prostate cancer cells using dual aptamer-modified gold nanostars

Jo, Hunho,Youn, Hyungjun,Lee, Seonghwan,Ban, Changill The Royal Society of Chemistry 2014 Journal of Materials Chemistry B Vol.2 No.30

<P>Although various studies related to nanoparticles-based photothermal therapy have been actively performed, an epoch-making photothermolysis therapy exhibiting both high selectivity and efficiency has yet not been discovered. For the first time, we have developed novel valuable therapeutic complexes, namely, dual aptamer-modified gold nanostars, for the targeting of prostate cancers, including PSMA(+) and PSMA(−) cells. The synthesized probes were characterized through several techniques, including UV-VIS spectral analysis, DLS analysis, zeta potential measurements, and TEM imaging, and were subsequently subjected to cytotoxicity tests, cell uptake confirmation, and <I>in vitro</I> photothermal therapy. The homogeneously well-fabricated nanostars presented high selectivity to prostate cancer cells and extremely high efficiency for therapy using an 808 nm laser under an irradiance of 0.3 W cm<SUP>−2</SUP>, which is lower than the permitted value for skin exposure (0.329 W cm<SUP>−2</SUP>). It is anticipated that this novel photothermal agent will become the general platform for targeted therapy.</P>

Crystallization and X-ray crystallographic analysis of ribose 5-phosphate isomerase B in complex with its ligand from Vibrio vulnificus

Taek Hun Kwon,Kyoungin Min,Matthias Wolf,Changill Ban,Tae Gyun Kim 한국구조생물학회 2022 Biodesign Vol.10 No.2

Ribose 5-phosphate isomerase is an enzyme that interconverts ribose 5-phosphate and ribulose 5-phosphate in the pentose phosphate pathway, which participates in NADPH generation, as well as an oxidative and non-oxidative synthesis of pentose sugars. Two distinct forms, ribose 5-phosphate isomerase A (RpiA) and ribose 5-phosphate isomerase B (RpiB), show no sequence identity even though they exist as ubiquitous, highly-conserved proteins in most kingdoms. RpiB from pathogenic, marine Vibrio vulnificus YJ016 (VvRpiB) was purified, crystallized, and analyzed to determine its structure in the apo form and in complex with a ligand. Crystals of the apo form of VvRpiB diffracted X-rays to 3.06 Å resolution, belonging to tetragonal space group I41 while co-crystals of VvRpiB with R5P belonged to the monoclinic space group C2 and diffracted X-rays to 2.07 Å resolution.

Modulated nicking endonuclease function by the N‐terminal extended region of the smr domain in human Bcl‐3 binding protein

Jeong, Eui Young,Kim, Tae Gyun,Ban, Changill Wiley Subscription Services, Inc., A Wiley Company 2012 Proteins Vol.80 No.1

Enhanced electrochemical sensing of leukemia cells using drug/lipid co-immobilized on the conducting polymer layer

Gurudatt, N.G.,Naveen, M. Halappa,Ban, Changill,Shim, Yoon-Bo Elsevier 2016 Biosensors & bioelectronics Vol.86 No.-

<P><B>Abstract</B></P> <P>Electrochemical biosensors using five anticancer drug and lipid molecules attached on the conducting polymer layer to obtain the orientation of drug molecules toward cancer cells, were evaluated as sensing materials and their performances were compared. Conjugation of the drug molecules with a lipid, phosphatidylcholine (PC) has enhanced the sensitivity towards leukemia cells and differentiates cancer cells from normal cells. The composition of each layer of sensor probe was confirmed by electrochemical and surface characterization experiments. Both impedance spectroscopy and voltammetry show the enhanced interaction of leukemia cells using the drug/lipid modified sensor probe. As the number of leukemia cells increased, the charge transfer resistance (R<SUB>ct</SUB>) in impedance spectra increased and the amine oxidation peak current of drug molecules in voltammograms decreased at around 0.7–1.0V. Of test drug molecules, raltitrexed (Rtx) showed the best performance for the cancer cells detection. Cancer and normal cell lines from different origins were examined to evaluate the degree of expression of folate receptors (FR) on cells surface, where cervical HeLa cell line was found to be shown the highest expression of the receptor. Impedance and chronoamperometric experiments for leukemia cell line (Jurkat E6-1) showed linear dynamic ranges of 1.0×10<SUP>3</SUP>–2.5×10<SUP>5</SUP> cells/mL and 1.0×10<SUP>3</SUP>–8.0×10<SUP>3</SUP> cells/mL with detection limits of 68±5 cells/mL and 21±3 cells/mL, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Five drug molecules were compared in-terms of their analytical response. </LI> <LI> Leukemia cells were electrochemically detected using drug/lipid modified sensor. </LI> <LI> ATRA treatment showed an increase in the cell surface expression of FR-β. </LI> </UL> </P>

Dual-target gene silencing by using long, synthetic siRNA duplexes without triggering antiviral responses

Chang, Chan Il,Kang, Hye Suk,Ban, Changill,Kim, Soyoun,Lee, Dong-ki Springer-Verlag 2009 Molecules and cells Vol.27 No.6

<P>Chemically synthesized small interfering RNAs (siRNAs) can specifically knock-down expression of target genes via RNA interference (RNAi) pathway. To date, the length of synthetic siRNA duplex has been strictly maintained less than 30 bp, because an early study suggested that double-stranded RNAs (dsRNAs) longer than 30 bp could not trigger specific gene silencing due to the induction of nonspecific antiviral interferon responses. Contrary to the current belief, here we show that synthetic dsRNA as long as 38 bp can result in specific target gene silencing without nonspecific antiviral responses. Using this longer duplex structure, we have generated dsRNAs, which can simultaneously knock-down expression of two target genes (termed as dual-target siRNAs or dsiRNAs). Our results thus demonstrate the structural flexibility of gene silencing siRNAs, and provide a starting point to construct multifunctional RNA structures. The dsiRNAs could be utilized to develop a novel therapeutic gene silencing strategy against diseases with multiple gene alternations such as viral infection and cancer.</P>

Aptasensor for ampicillin using gold nanoparticle based dual fluorescence-colorimetric methods.

Song, Kyung-Mi,Jeong, Euiyoung,Jeon, Weejeong,Cho, Minseon,Ban, Changill Springer-Verlag 2012 ANALYTICAL AND BIOANALYTICAL CHEMISTRY Vol.402 No.6

<P>A gold nanoparticle based dual fluorescence-colorimetric method was developed as an aptasensor to detect ampicillin using its single-stranded DNA (ssDNA) aptamer, which was discovered by a magnetic bead-based SELEX technique. The selected aptamers, AMP4 (5'-CACGGCATGGTGGGCGTCGTG-3'), AMP17 (5'-GCGGGCGGTTGTATAGCGG-3'), and AMP18 (5'-TTAGTTGGGGTTCAGTTGG-3'), were confirmed to have high sensitivity and specificity to ampicillin (K (d), AMP7 = 9.4 nM, AMP17 = 13.4 nM, and AMP18 = 9.8 nM, respectively). The 5'-fluorescein amidite (FAM)-modified aptamer was used as a dual probe for observing fluorescence differences and color changes simultaneously. The lower limits of detection for this dual method were a 2 ng/mL by fluorescence and a 10 ng/mL by colorimetry for ampicillin in the milk as well as in distilled water. Because these detection limits were below the maximum residue limit of ampicillin, this aptasensor was sensitive enough to detect antibiotics in food products, such as milk and animal tissues. In addition, this dual aptasensor will be a more accurate method for antibiotics in food products as it concurrently uses two detection methods: fluorescence and colorimetry.</P>

Stromal Cell Derived Factor‐1 (SDF‐1) Targeting Reperfusion Reduces Myocardial Infarction in Isolated Rat Hearts

Jang, Young‐,Ho,Kim, June‐,Hong,Ban, Changill,Ahn, Kyohan,Cheong, Jae‐,Hun,Kim, Hyung‐,Hoi,Kim, Jung‐,Soo,Park, Yong‐,Hyun,Kim, Jun,Chun, Kook‐,Jin,Lee, Gyeon Blackwell Publishing Ltd 2012 CARDIOVASCULAR THERAPEUTICS Vol.30 No.5

<P><B>SUMMARY</B></P><P>Recent studies have shown that stromal cell derived factor‐1 (SDF‐1), first known as a cytokine involved in recruiting stem cells into injured organs, confers myocardial protection in myocardial infarction, which is not dependent on stem cell recruitment but related with modulation of ischemia‐reperfusion (I/R) injury. However, the effect of SDF has been studied only in a preischemic exposure model, which is not clinically relevant if SDF is to be used as a therapeutic agent. Our study was aimed at evaluating whether or not SDF‐1 confers cardioprotection during the reperfusion period. Hearts from SD rats were isolated and perfused with the Langendorff system. Proximal left coronary artery ligation, reperfusion, and SDF perfusion in KH buffer was done according to study protocol. Area of necrosis (AN) relative to area at risk (AR) was the primary endpoint of the study. Significant reduction of AN/AR by SDF in an almost dose‐dependent manner was noted during both the preischemic exposure and reperfusion periods. In particular, infusion of a high concentration of SDF (25 nM/L) resulted in a dramatic reduction of infarct size, which was greater than that achieved with ischemic pre‐ or postconditioning. SDF perfusion during reperfusion was associated with a similar significant reduction of infarct size as preischemic SDF exposure. Further studies are warranted to assess the potential of SDF as a therapeutic agent for reducing I/R injury in clinical practice.</P>

A turn-on two-photon fluorescent probe for ATP and ADP

Sreenivasa Rao, Alla,Kim, Dokyoung,Nam, Hyoseok,Jo, Hunho,Kim, Ki Hean,Ban, Changill,Ahn, Kyo Han The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.26

<P>An acedan derivative containing Zn(<SMALL>II</SMALL>)–DPA has been developed as a two-photon probe for nucleoside phosphates, which shows enhanced fluorescence toward ATP and ADP at physiological pH 7.4 among other competing anions including AMP; the probe is permeable to cell membranes and thus can be directly used for two-photon imaging of ATP and ADP in live cells.</P> <P>Graphic Abstract</P><P>A novel two-photon fluorescent probe for ATP is developed for the first time, which is used for imaging ATP in live cells. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc17629g'> </P>