Chil Hwan Oh

Highly Sensitive Immunoassay of Lung Cancer Marker Carcinoembryonic Antigen Using Surface-Enhanced Raman Scattering of Hollow Gold Nanospheres

A quick and reproducible surface-enhanced Raman scattering (SERS)-based immunoassay technique, using hollow gold nanospheres (HGNs) and magnetic beads, has been developed. Here, HGNs show strong enhancement effects from individual particles because hot spots can be localized on the pinholes in the hollow particle structure. Thus, HGNs can be used for highly reproducible immunoanalysis of cancer markers. Magnetic beads were used as supporting substrates for the formation of the immunocomplex. This SERS-based immunoassay technique overcomes the problem of slow immunoreaction caused by the diffusion-limited kinetics on a solid substrate because all of the reactions occur in solution. For the validation of our SERS immunoassay, a well-known lung cancer marker, carcinoembryonic antigen (CEA), was used as a target marker. According to our experimental results, the limit of detection (LOD) was determined to be 1-10 pg/mL, this value being about 100-1000 times more sensitive than the LOD of enzyme-linked immunosorbent assay. Furthermore, the assay time took less than 1 h, including washing and optical detection steps.

Surface-enhanced Raman scattering imaging of HER2 cancer markers overexpressed in single MCF7 cells using antibody conjugated hollow gold nanospheres

Antibody-conjugated hollow gold nanospheres (HGNs) have been used for the SERS imaging of HER2 cancer markers overexpressed in single MCF7 cells. SERS mapping images show that HGNs have much better homogeneous scattering properties than silver nanoparticles. The results demonstrate the potential feasibility of HGNs as highly sensitive and homogeneous sensing probes for biological imaging of cancer markers in live cells.

SERS imaging of HER2-overexpressed MCF7 cells using antibody-conjugated gold nanorods

Antibody-conjugated gold nanorods (GNRs) have been used for the targeting and imaging of specific cancer markers expressed on the surface membrane of cancer cells. GNRs with various aspect ratios were fabricated, and their surface-enhanced Raman scattering enhancement effects were evaluated. To attach the GNRs selectively onto the targets in cancer cells, specific antibodies were immobilized on the surface of GNRs using the layer-by-layer deposition method. First, Raman reporter molecules, mercaptopyridine, were attached to the surface of GNRs, and their surface charge was modified using poly(sodium 4-styrene-sulfonate) to make the surface charge negative. Then, anti-rabbit IgGs were immobilized onto the surface of the GNRs by electrostatic interactions. HER2 markers, expressed on the cell surface, were treated with anti-HER2 primary antibodies. Finally, the functionalized nanoprobes, conjugated with secondary antibodies, were attached to the markers on cancer cells by antibody-antibody interactions. In the present study, MCF7 cells overexpressing breast cancer marker HER2 were used as the optical imaging targets. Our experimental results demonstrate the potential feasibility of antibody-conjugated GNRs for the highly sensitive targeting and imaging of biomarkers expressed on the surface membrane of cancer cells.

Highly reproducible immunoassay of cancer markers on a gold-patterned microarray chip using surface-enhanced Raman scattering imaging

This paper reports a highly reproducible immunoassay of cancer markers using surface-enhanced Raman scattering (SERS) imaging. SERS is a highly sensitive detection method but it is limited in its ability to achieve reproducible signal enhancement because of the difficulty with precisely controlling the uniform distribution of hot junctions. Consequently, inconsistent enhancement prevents the wide exploitation of SERS detection as a bio-detection tool for quantitative analysis. To resolve this problem, we explored the use of a SERS imaging-based immunoassay. For this purpose, Raman reporter-labeled hollow gold nanospheres (HGNs), were manufactured and antibodies were immobilized onto their surfaces for targeting specific antigens. After the formation of sandwich immunocomplexes using these functional HGNs on the surfaces of gold patterned wells, the SERS mapping images were measured. For target protein markers, 12×9 pixels were imaged using a Raman mapping technique in the 0-10(-4) g/mL concentration range, and the SERS signals for 66 pixels were averaged. Here, the SERS imaging-based assay shows much better correlations between concentration and intensity than does the conventional point-based assay. The limits of detection were determined to be 0.1 pg/mL and 1.0 pg/mL for angiogenin (ANG) and alpha-fetoprotein (AFP), respectively. This detection sensitivity is increased by three or four orders of magnitude over that of conventional ELISA method. The detectable dynamic range for SERS imaging (10(-4)-10(-12) g/mL) is also much wider than that for ELISA (10(-6)-10(-9) g/mL).

Green Tea Polyphenol Epigallocatechin-3-Gallate Suppresses Collagen Production and Proliferation in Keloid Fibroblasts via Inhibition of the STAT3-Signaling Pathway

Keloids are benign skin tumors characterized by collagen accumulation and hyperproliferation of fibroblasts. To find an effective therapy for keloids, we explored the pharmacological potential of (-)-epigallocatechin-3-gallate (EGCG), a widely investigated tumor-preventive agent. When applied to normal and keloid fibroblasts (KFs) in vitro, proliferation and migration of KFs were more strongly suppressed by EGCG than normal fibroblast proliferation and migration (IC(50): 54.4 microM (keloid fibroblast (KF)) versus 63.0 microM (NF)). The level of Smad2/3, signal transducer and activator of transcription-3 (STAT3), and p38 phosphorylation is more enhanced in KFs, and EGCG inhibited phosphorylation of phosphatidylinositol-3-kinase (PI3K), extracellular signal-regulated protein kinase 1/2 (ERK1/2), and STAT3 (Tyr705 and Ser727). To evaluate the contribution of these pathways to keloid pathology, we treated KFs with specific inhibitors for PI3K, ERK1/2, or STAT3. Although a PI3K inhibitor significantly suppressed proliferation, PI3K and MEK/ERK inhibitors had a minor effect on migration and collagen production. However, a JAK2/STAT3 inhibitor and a STAT3 siRNA strongly suppressed proliferation, migration, and collagen production by KFs. We also found that treatment with EGCG suppressed growth and collagen production in the in vivo keloid model. This study demonstrates that EGCG suppresses the pathological characteristics of keloids through inhibition of the STAT3-signaling pathway. We propose that EGCG has potential in the treatment and prevention of keloids.

Gd‐DOTA Conjugate of RGD as a Potential Tumor‐Targeting MRI Contrast Agent

Targeted delivery of contrast agents (CAs) with specific tumor recognition sites and simultaneous monitoring of the growth and metastasis of tumors in the body is an important goal in diagnostic molecular imaging. RGD (Arg-Gly-Asp) peptide is well known to have a relatively high and specific affinity for anb3-integrin, which is over-expressed in nascent endothelial cells during angiogenesis (formation of new blood vessels) in various tumor types and not in inactive endothelial cells. The expression of an endothelial anb3-integrin has been shown to correlate with tumor grade and thus plays a significant role in diagnosis of tumors. Some progress in tumor-targeted imaging by positron emission tomography (PET) or near-infrared fluorescence (NIRF) has recently been made with the aid of RGD complexes labeled with radioactive isotopes or fluorescent tags. Despite the usefulness of PET and NIRF, their applications are rather limited because of inherent problems such as light scattering, the invasive nature of data collection, photo-bleaching, and poor resolution. Molecular magnetic resonance imaging (MRI), however, can not only overcome these restrictions, but, with the assistance of a CA that catalytically shortens the relaxation time of the protons of nearby water molecules, can also provide excellent anatomy images. Thermodynamically stable, water-soluble, and highly paramagnetic Gd complexes, each bearing a multidentate ligand and at least one coordinated water molecule, have demonstrated high relaxivity and have therefore served as versatile MRI CAs. Among the early MRI CAs approved for clinical use are Dotarem and Omniscan . These Gd complexes incorporate the macrocycle 1,4,7,10-tetraazacyclododecane-1,4,7,10tetraacetic acid (DOTA) as ligand and exhibit high thermodynamic stability. The fact that DOTA can employ at least one carboxylate to form a conjugate with a peptide such as RGD provides additional advantages for the preparation of targetspecific MRI CAs. In this regard, GdACHTUNGTRENNUNG(DOTA) conjugated with RGD should be an attractive candidate as a paramagnetic MRI CA for tumor-targeting. We now therefore wish to introduce the Gd ACHTUNGTRENNUNG(DOTA) conjugate of RGD, designed to monitor the activation of anb3-integrin in tumor tissue. The synthesis initially involved conjugation of DOTA and the cyclic pentapeptide c ACHTUNGTRENNUNG(RGDYK) as described by others. The DOTA-RGD conjugate thus prepared was purified and isolated by preparative HPLC. The Gd-DOTA-RGD complex was prepared by treatment of the DOTA-RGD with GdCl3·6 H2O in water. The final product was isolated as a white solid after purification by preparative HPLC. MALDI-TOF-MS shows a peak corresponding to [M+H H2O] (m/z 1161.50; calculated MW for C43H67GdN13O16 = 1178.39). The proton relaxivities—R1 and R2—of Gd-DOTA-RGD are 7.4 0.20 mm 1 s 1 and 4.0 0.24 mm 1 s , respectively at 298 K and 64 MHz. Gd-DOTA-RGD exhibits higher longitudinal relaxivity than small-molecule MRI CAs (for the data see the Supporting Information), which may be explained in terms of slower molecular tumbling (tg) as a result of the increase in molecular weight achieved through conjugation with RGD. In [a] J.-A. Park, J.-J. Lee, Prof. Y. Chang Department of Medical and Biological Engineering Kyungpook National University Daegu 702-701 (Korea) [b] Prof. J.-C. Jung Department of Biology, Kyungpook National University Daegu 702-701 (Korea) [c] Dr. D.-Y. Yu Korea Research Institute of Bioscience and Biotechnology Daejeon 305-806 (Korea) [d] Prof. C. Oh Department of Dermatology, College of Medicine, Korea University Seoul 152-703 (Korea) [e] Prof. C. Oh, S. Ha Research Institute for Skin Image College of Medicine, Korea University Seoul 152-703 (Korea) [f] Prof. T.-J. Kim Department of Applied Chemistry, Kyungpook National University Daegu 702-701 (Korea) Fax: (+ 82) 53-950-6594 E-mail : tjkim@knu.ac.kr [g] Prof. Y. Chang Department of Diagnostic Radiology and Molecular Medicine Kyungpook National University Daegu 702-701 (Korea) Fax: (+ 82) 53-422-2677 E-mail : ychang@knu.ac.kr Supporting information for this article is available on the WWW under http ://www.chembiochem.org or from the author.

Quantitative measurement of desquamation and skin elasticity in diabetic patients

Background/aims: Diabetes mellitus is responsible for many cutaneous alterations. Xerosis and sclerotic change of the skin are the most common findings. Recently non‐ invasive computerized devices have been developed and used for determining the desquamation rate and measuring the mechanical properties of the skin. Using these devices, the necessity to characterize the conditions of the skin in the healthy as well as the diseased state is increasing. The aim of this study was to compare the elasticity and desquamation rate between the diabetic population and the normal population using non‐invasive, objective methods.

Iatrogenic Mycobacterium abscessus infection associated with acupuncture: clinical manifestations and its treatment

Background  Mycobacterial infections transmitted by acupuncture are an emerging problem. There have been two reports of mycobacterial infections complicating acupuncture in the English literature.

Solar Damage in Skin Tumors: Quantification of Elastotic Material

Background: The elastotic changes of the dermis are thought to be the primary indicator of the cumulative sun exposure of the dermis. The changes of elastotic material have been evaluated by several previous methods, but these did not quantitatively measure the amount of elastic tissue. Objective: The purpose of this study was to quantify dermal elastosis and to assess the significance of sun exposure in the pathogenesis of nonmelanomatous skin tumors such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and Bowen’s disease (BD). Methods: Ninety-nine sections from biopsy specimens of histopathologically proven BCC, SCC and BD were stained with Verhoeff-van Gieson stains. We studied the amount of elastotic material adjacent to the tumor by image analysis. Results: There was a 3- to 4-fold increase in the amount of elastotic material in BCC and SCC compared to the sun-exposed skin of normal controls (p < 0.0001). The amount of elastotic material was increased 1.3 times in BD as compared with the nonexposed skins of normal controls (p < 0.01). Conclusion: We demonstrated a quantitative relationship between cumulative solar exposure and skin cancer such as SCC, BCC and BD.

Influence of surface charge of gold nanorods on skin penetration

The skin plays an important role as a protective barrier against toxic environments and also is a route of drug administration. In spite of evidence for and interest in the skin penetration of nanoparticles, no study has examined the effect of nanoparticle surface charge on percutaneous absorption. In this study, we investigated the effect of surface charges of gold nanorods (GNs) on skin penetration.