Publications by authors named "Chang-Seuk Lee"

12 Publications

  • Page 1 of 1

Label-Free Assay of Protein Kinase A Activity and Inhibition Using a Peptide-Based Electrochemical Sensor.

Biomedicines 2021 Apr 13;9(4). Epub 2021 Apr 13.

Department of ICT Environmental Health System, Graduate School, Soonchunhyang University, Asan 31538, Korea.

We propose a simple label-free electrochemical biosensor for monitoring protein kinase activity and inhibition using a peptide-modified electrode. The biosensor employs cys-kemptide (CLRRASLG) as a substrate peptide which was immobilized on the surface of a gold electrode via the self-assembly of the thiol terminals in cysteine (C) residues. The interaction between protein kinase A (PKA) and adenosine 5'-triphosphate (ATP) on the cys-kemptide immobilized electrode can cause the transfer of ATP terminal phosphates to the peptide substrates at serine (S) residues, which alters the surface charge of the electrode, thus enabling monitoring of the PKA activity via measuring the interfacial electron transfer resistance with electrochemical impedance spectroscopy. The proposed sensor showed reliable, sensitive, and selective detection of PKA activity with a wide dynamic range of 0.1-100 U/mL and a detection limit of 56 mU/mL. The sensor also exhibited high selectivity, rendering it possible to screen PKA inhibitors. Moreover, the sensor can be employed to evaluate the activity and inhibition of PKA in real samples.
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http://dx.doi.org/10.3390/biomedicines9040423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069798PMC
April 2021

PrP Aptamer Conjugated-Gold Nanoparticles for Targeted Delivery of Doxorubicin to Colorectal Cancer Cells.

Int J Mol Sci 2021 Feb 17;22(4). Epub 2021 Feb 17.

Department of Biochemistry, Soonchunhyang University College of Medicine, Cheonan 31151, Korea.

Anticancer drugs, such as fluorouracil (5-FU), oxaliplatin, and doxorubicin (Dox) are commonly used to treat colorectal cancer (CRC); however, owing to their low response rate and adverse effects, the development of efficient drug delivery systems (DDSs) is required. The cellular prion protein PrP, which is a cell surface glycoprotein, has been demonstrated to be overexpressed in CRC, however, there has been no research on the development of PrP-targeting DDSs for targeted drug delivery to CRC. In this study, PrP aptamer (Apt)-conjugated gold nanoparticles (AuNPs) were synthesized for targeted delivery of Dox to CRC. Thiol-terminated PrP-Apt was conjugated to AuNPs, followed by hybridization of its complementary DNA for drug loading. Finally, Dox was loaded onto the AuNPs to synthesize PrP-Apt-functionalized doxorubicin-oligomer-AuNPs (PrP-Apt DOA). The PrP-Apt DOA were spherical nanoparticles with an average diameter of 20 nm. Treatment of CRC cells with PrP-Apt DOA induced reactive oxygen species generation by decreasing catalase and superoxide dismutase activities. In addition, treatment with PrP-Apt DOA inhibited mitochondrial functions by decreasing the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, complex 4 activity, and oxygen consumption rates. Compared to free Dox, PrP-Apt DOA decreased proliferation and increased apoptosis of CRC cells to a greater degree. In this study, we demonstrated that PrP-Apt DOA targeting could effectively deliver Dox to CRC cells. PrP-Apt DOA can be used as a treatment for CRC, and have the potential to replace existing anticancer drugs, such as 5-FU, oxaliplatin, and Dox.
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http://dx.doi.org/10.3390/ijms22041976DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922473PMC
February 2021

α-Synuclein Oligomer Detection with Aptamer Switch on Reduced Graphene Oxide Electrode.

Nanomaterials (Basel) 2020 Apr 27;10(5). Epub 2020 Apr 27.

Department of Chemistry, Soonchunhyang University, Asan 31538, Korea.

Protein aggregation of alpha-synuclein (α-Syn) is implicated in Parkinson's disease (PD), and, thus, α-Syn aggregates are a potentially promising candidate biomarker for PD diagnosis. Here, we describe a simple and sensitive electrochemical sensor to monitor the aggregation of α-Syn for early PD diagnosis. The sensor utilizes methylene blue (MB)-tagged aptamer (Apt) adsorbed on electrochemically reduced graphene oxide (ERGO) by π-π stacking. The binding of α-Syn oligomer to the Apt induces desorption of the Apt from the ERGO surface, which leads to the electrochemical signal change. The resulting sensor allowed the highly sensitive and selective detection of α-Syn oligomer according to the voltammetric change. Under optimized conditions, the linear range of detection was observed to be from 1 fM to 1 nM of the α-Syn oligomer and the limit of detection (LOD) was estimated to be 0.64 fM based on S/N = 3. The sensor also showed good reproducibility and stability, enabling real sample analysis of the α-Syn oligomer in human blood serum. With its ultrasensitivity and good performance for α-Syn oligomer detection, the sensor provides one promising tool for the early diagnosis of PD.
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http://dx.doi.org/10.3390/nano10050832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7711764PMC
April 2020

Label-free assay of protein kinase A activity and inhibition in cancer cell using electrochemically-prepared AuNP/rGO nanohybrid electrode modified with C-Kemptide.

Talanta 2020 Aug 4;215:120899. Epub 2020 Mar 4.

Department of Chemistry, Soonchunhyang University, Asan, 31538, Republic of Korea. Electronic address:

A simple, label-free and sensitive electrochemical assay is described for the detection of protein kinase A (PKA) activity and inhibition in cancer cell by measuring the change in electrochemical impedance upon phosphorylation. The assay utilized gold nanoparticle (AuNP) and reduced graphene oxide (rGO) nanohybrid which was synthesized and deposited on the electrode from GO and Au precursors by one-pot electrochemical synthesis. As-prepared AuNP/rGO electrode was employed to immobilize C-Kemptide peptide substrates which was phosphorylated in the presence of PKA and ATP. The resulting assay allowed effective, selective and sensitive monitoring of PKA activity according to the impedimetric change in the range of 0.1-500 U/mL, and the detection limit (LOD) is 53 mU/mL. It could also be used for the screening of protein kinase inhibitors. Furthermore, the assay could be applied for the evaluation of PKA activity and inhibition in HeLa cell samples. Therefore, the proposed assay provides one promising tool for PKA activity detection and inhibitor screening with excellent performance.
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http://dx.doi.org/10.1016/j.talanta.2020.120899DOI Listing
August 2020

In Vivo and In Vitro Anticancer Activity of Doxorubicin-loaded DNA-AuNP Nanocarrier for the Ovarian Cancer Treatment.

Cancers (Basel) 2020 Mar 9;12(3). Epub 2020 Mar 9.

Department of Chemistry, Soonchunhyang University, Asan 31538, Korea.

In this study, we have determined the anticancer activity of doxorubicin (Dox)-loaded DNA/gold nanoparticle (AuNP) nanocarrier (Dox-DNA-AuNP) for the treatment of ovarian cancer. The anticancer effect of Dox-DNA-AuNP was evaluated in vitro using the EZ-Cytox cell viability assay on three human ovarian cancer cell lines, SK-OV-3, HEY A8, and A2780. Dox-DNA-AuNP exhibited outstanding activity with good IC values of 4.8, 7.4, and 7.6 nM for SK-OV-3, HEY A8, and A2780, respectively. In vivo evaluation further demonstrated the superior anticancer effects of Dox-DNA-AuNP by inhibiting tumor growth compared to free Dox in an established SK-OV-3 xenograft mice model. Dox-DNA-AuNP showed about a 2.5 times higher tumor growth inhibition rate than free Dox. Furthermore, the immunohistochemical analysis of Ki67 antigen expression showed the lowest number of proliferative cells in the ovarian tumor tissue treated with Dox-DNA-AuNP. These results suggest Dox-DNA-AuNP might be a potential effective agent in ovarian cancer chemotherapy.
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http://dx.doi.org/10.3390/cancers12030634DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7139456PMC
March 2020

Scalable Preparation of Low-Defect Graphene by Urea-Assisted Liquid-Phase Shear Exfoliation of Graphite and Its Application in Doxorubicin Analysis.

Nanomaterials (Basel) 2020 Feb 5;10(2). Epub 2020 Feb 5.

Department of Chemistry, Soonchunhyang University, Asan 31538, Korea.

The mass production of graphene is of great interest for commercialization and industrial applications. Here, we demonstrate that high-quality graphene nanosheets can be produced in large quantities by liquid-phase shear exfoliation under ambient conditions in organic solvents, such as 1-methyl-2-pyrrolidinone (NMP), with the assistance of urea as a stabilizer. We can achieve low-defect graphene (LDG) using this approach, which is relatively simple and easily available, thereby rendering it to be an efficient route for the mass production of graphene. We also demonstrate the electrochemical sensing of an LDG-modified electrode for the determination of doxorubicin (DOX). The sensor shows an enhanced electrocatalytic property towards DOX, leading to a high sensitivity (7.23 × 10 μM/μA) with a detection limit of 39.3 nM (S/N = 3).
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http://dx.doi.org/10.3390/nano10020267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7075141PMC
February 2020

Single-Walled Carbon Nanotubes Decorated with Dendrimer-Encapsulated Platinum Nanoparticles as Catalytic Immobilization Matrix for Amperometric Sensing of Glutamate.

J Biomed Nanotechnol 2019 Dec;15(12):2321-2331

Herein, we report the functional decoration of single-walled carbon nanotubes (swCNTs) with Pt dendrimer-encapsulated nanoparticles (Pt DENs) (dia. (1.78 ± 0.18) nm) for the amperometric sensing of glutamate. The functional decoration of swCNTs was carried out via electrochemical grafting of Pt DENs onto swCNTs, and subsequent cross-linking of glutamate oxidase (GluOx) enzymes to the grafted Pt DENs on swCNT surfaces. The critical role of Pt DENs as catalytic immobilization matrix allowed both the immobilization of GluOx enzymes while maintaining the enzymatic activity of GluOx, and the electrocatalytic oxidation of H₂O₂ generated enzymatically in the presence of glutamate. Taking advantage of Pt DENs as catalytic immobilization matrix, the resulting swCNTs films, denoted as GluOx/Pt DEN/swCNTs, were applied as amperometric sensing platforms that display superior analytical characteristics, including sensitivity, selectivity, stability, and reproducibility, to the non-catalytic counterpart (i.e., GluOx/swCNTs), which led to the promising application of GluOx/Pt DEN/swCNTs to the practical analysis of glutamate in real samples.
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http://dx.doi.org/10.1166/jbn.2019.2863DOI Listing
December 2019

Electrochemical Detection of Ultratrace Lead Ion through Attaching and Detaching DNA Aptamer from Electrochemically Reduced Graphene Oxide Electrode.

Nanomaterials (Basel) 2019 May 30;9(6). Epub 2019 May 30.

Department of Chemistry, Soonchunhyang University, Asan 31538, Korea.

This paper describes a simple strategy for the ultratrace level detection of Pb ion based on G-quadruplex DNA and an electrochemically reduced graphene oxide (ERGO) electrode. First, ERGO was formed on a glassy carbon electrode (GCE) by the reduction of graphene oxide (GO) using cyclic voltammetry. Subsequently, a methylene blue (MB)-tagged, guanine-rich DNA aptamer (Apt) was attached to the surface of ERGO via π-π interaction, leading to the Apt-modified ERGO electrode. The presence of Pb could generate the folding of Apt to a G-quadruplex structure. The formation of G-quadruplex resulted in detaching the Apt from the ERGO/GCE, leading to a change in redox current of the MB tag. Electrochemical measurements showed the proposed sensor had an exceptional sensitivity for Pb with a linear range from 10 to 10 M and a detection limit of 0.51 fM. The sensor also exhibited high selectivity for Pb, as well as many other advantages, such as stability, reproducibility, regeneration, as well as simple fabrication and operation processes.
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http://dx.doi.org/10.3390/nano9060817DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6630585PMC
May 2019

One-Step Electrochemical Fabrication of Reduced Graphene Oxide/Gold Nanoparticles Nanocomposite-Modified Electrode for Simultaneous Detection of Dopamine, Ascorbic Acid, and Uric Acid.

Nanomaterials (Basel) 2017 Dec 30;8(1). Epub 2017 Dec 30.

Department of Chemistry, Soonchunhyang University, Asan 31538, Korea.

Here, we introduce the preparation of the hybrid nanocomposite-modified electrode consisting of reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) using the one-step electrochemical method, allowing for the simultaneous and individual detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). RGO/AuNPs nanocomposite was formed on a glassy carbon electrode by the co-reduction of GO and Au using the potentiodynamic method. The RGO/AuNPs nanocomposite-modified electrode was produced by subjecting a mixed solution of GO and Au to cyclic sweeping from -1.5 V to 0.8 V (vs. Ag/AgCl) at a scan rate 10 mV/s for 3 cycles. The modified electrode was characterized by scanning electron microscopy, Raman spectroscopy, contact angle measurement, electrochemical impedance spectroscopy, and cyclic voltammetry. Voltammetry results confirm that the RGO/AuNPs nanocomposite-modified electrode has high catalytic activity and good resolution for the detection of DA, AA, and UA. The RGO/AuNPs nanocomposite-modified electrode exhibits stable amperometric responses for DA, AA, and UA, respectively, and its detection limits were estimated to be 0.14, 9.5, and 25 μM. The modified electrode shows high selectivity towards the determination of DA, AA, or UA in the presence of potentially active bioelements. In addition, the resulting sensor exhibits many advantages such as fast amperometric response, excellent operational stability, and appropriate practicality.
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http://dx.doi.org/10.3390/nano8010017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791104PMC
December 2017

Doxorubicin-loaded oligonucleotide conjugated gold nanoparticles: A promising in vivo drug delivery system for colorectal cancer therapy.

Eur J Med Chem 2017 Dec 31;142:416-423. Epub 2017 Aug 31.

Department of Chemistry, Soonchunhyang University, Asan 31538, Republic of Korea. Electronic address:

In this study, we propose doxorubicin (DOX) loaded oligonucleotides (ONTs) attached to gold nanoparticles (AuNPs) as a drug delivery system for cancer chemotherapy. DOX is one of the representative cancer chemotherapy agents and is widely used by many researchers as a chemotherapy agent in the drug delivery system. Due to the advantages of AuNPs such as simple steps in synthesis, high surface-area-to-volume ratio, and biocompatibility, we utilized AuNPs as drug delivery vehicle. AuNPs were synthesized by chemical reduction to be 13 nm diameter. The G-C rich oligonucleotides were used both for drug loading sites and AuNPs capping agents. 80% of DOX in solution could be bound to ONTs on AuNPs to became DOX-loaded AuNPs coated with ONTs (Doxorubicin-Oligomer-AuNP, DOA), and about 28% of loaded DOX was released from the as-prepared DOA. Confocal microscopy observation showed that DOA was well transported into cells, and finally the DOX was released into the cell nucleus. The drug's efficacies such as in vitro cytotoxicity and in vivo tumor growth inhibition were demonstrated with SW480 colon cancer cell line and a xenograft mouse model. MTT assay was performed to see the cytotoxicity effect on SW480 cells treated with DOA for 24 h, and the cell viability was determined to be 41.77% (p < 0.001). When DOA was administered regularly to a tumor bearing mouse, the tumor growth inhibition degree was examined by measuring the tumor size. The treatment-control (T/C) ratio was found to be 0.69. Thus, our results suggest the use of DOAs as promising drug delivery systems for colorectal cancer therapy.
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http://dx.doi.org/10.1016/j.ejmech.2017.08.063DOI Listing
December 2017

Oncogenic function of angiopoietin-2 and its modulation of tumor progression in colorectal carcinoma.

Oncol Lett 2017 Jul 18;14(1):553-560. Epub 2017 May 18.

Department of Pathology, College of Medicine, Soonchunhyang University, Dongnam-gu, Cheonan, Chungcheongnam-do 330-721, Republic of Korea.

Angiopoietin-2 (Ang-2) has been investigated in cancer primarily in terms of its angiogenic function, and its role as an oncogene has yet to be elucidated. The current study hypothesized that Ang-2 may be an oncogene and have a function in tumor progression. An investigation of the function of Ang-2 in the LoVo colorectal cancer (CRC) cell line , which expresses a high level of Ang-2, was performed by knocking down endogenous expression with a targeted short hairpin RNA. The aggressive phenotypic effects of Ang-2 on experimental and control group cells were assessed using cell proliferation, migration and invasion assays. The association between Ang-2 expression levels and clinicopathological factors was evaluated in 415 CRC tissues using immunohistochemistry. Suppressing Ang-2 expression decreased cellular proliferation, invasion and migration in an study. Ang-2 overexpression was observed in 46% of patients with CRC and was significantly associated with pT (P=0.048), pN (P<0.001), venous invasion (P=0.023), lymphatic invasion (P<0.001) and tumor-node-metastasis stage (P=0.022). Furthermore, Ang-2 overexpression was an independent prognostic factor in pN stages 1 and 2. These results reveal that Ang-2 may be an oncogene in colorectal carcinogenesis and its expression may exert aggressive phenotypic effects during tumor progression. In addition, Ang-2 expression may serve as a prognostic marker and a potential drug target.
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http://dx.doi.org/10.3892/ol.2017.6203DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5494651PMC
July 2017

Graphene nanonet for biological sensing applications.

Nanotechnology 2013 Sep 21;24(37):375302. Epub 2013 Aug 21.

Department of Physics and Astronomy, Seoul National University, Seoul, Korea.

We report a simple but efficient method to fabricate versatile graphene nanonet (GNN)-devices. In this method, networks of V2O5 nanowires (NWs) were prepared in specific regions of single-layer graphene, and the graphene layer was selectively etched via a reactive ion etching method using the V2O5 NWs as a shadow mask. The process allowed us to prepare large scale patterns of GNN structures which were comprised of continuous networks of graphene nanoribbons (GNRs) with chemical functional groups on their edges. The GNN can be easily functionalized with biomolecules for fluorescent biochip applications. Furthermore, electrical channels based on GNN exhibited a rather high mobility and low noise compared with other network structures based on nanostructures such as carbon nanotubes, which was attributed to the continuous connection of nanoribbons in GNN structures. As a proof of concept, we built DNA sensors based on GNN channels and demonstrated the selective detection of DNA. Since our method allows us to prepare high-performance networks of GNRs over a large surface area, it should open up various practical biosensing applications.
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http://dx.doi.org/10.1088/0957-4484/24/37/375302DOI Listing
September 2013