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Viswanath B.,Gachon University | Kim S.,Gachon University | Kim S.,Graduate Gachon Medical Research Institute
TrAC - Trends in Analytical Chemistry | Year: 2016

Circulating tumor cells (CTCs) produced from primary tumors act as seeds for metastasis, leading to the majority of cancer-related deaths. Currently, in cancer research, these cells have attracted much attention in studying the process of metastasis. Various studies in the past decade have enlightened the role of CTCs as potential biomarkers in cancer diagnosis and prognosis. As a result, the analysis of CTCs could act as a substitute for characterizing the nature of primary tumors and provide unique insights into the metastatic process. The detection of CTCs in the blood samples of a cancer patient is technically challenging because of the extremely low abundance of CTCs among a large number of other blood cells. Therefore, novel methods for the detection of CTCs are highly recommended. In this feature article, we discuss the recent progress in nanotechnology for the detection of CTCs along with perspectives on future opportunities. © 2016 Elsevier B.V.

Ramasamy S.,Gachon University | Bennet D.,Gachon University | Kim S.,Gachon University | Kim S.,Graduate Gachon Medical Research Institute
RSC Advances | Year: 2015

Hybrid nanoparticles (NPs) with a mesoporous hollow structure have attracted great interest for biomolecule delivery, due to the easy fabrication process, the multi-functionalization capability for navigating to specific hosts and the high surface area for encapsulating therapeutic moieties. In the present study, hybrid ruthenium NPs were prepared with a dual template method by using colloidal amine functionalized silica particles and poloxamer 407. The results indicate that the size of the NPs can be controlled; smooth, spherical, monodispersed, negative surface charge potential, polycrystalline, and hollow interior architecture particles can be prepared. Also, the Brunauer-Emmett-Teller (BET) analysis shows a specific high surface area of 75 m2 g-1. The hybrid NP system also exhibits fluorescent properties. Thus this system could be a great advantage for cell trafficking. Then, cell cytotoxicity was evaluated in a real-time manner for two different cell lines using the electric cell-substrate impedance sensing (ECIS) system, and the results show that a higher than 100 μg ml-1 concentration is cytotoxic. The negatively charged surface NPs show higher cellular uptake through electrostatic interactions and binding at the cationic sites of the cell membrane, and also show high drug loading and potential for pH sensitive drug release. This hybrid NP system represents a promising nanocarrier for effective and favorable antitumor treatment and theranostic systems. © The Royal Society of Chemistry 2015.

Ramasamy S.,Gachon UniversityGyeonggi do | Bennet D.,Gachon UniversityGyeonggi do | Kim S.,Gachon UniversityGyeonggi do | Kim S.,Graduate Gachon Medical Research Institute
International Journal of Nanomedicine | Year: 2014

This review will present a brief discussion on the recent advancements of bioelectrical impedance cell-based biosensors, especially the electric cell-substrate impedance sensing (ECIS) system for screening of various bioactive molecules. The different technical integrations of various chip types, working principles, measurement systems, and applications for drug targeting of molecules in cells are highlighted in this paper. Screening of bioactive molecules based on electric cell-substrate impedance sensing is a trial-and-error process toward the development of therapeutically active agents for drug discovery and therapeutics. In general, bioactive molecule screening can be used to identify active molecular targets for various diseases and toxicity at the cellular level with nanoscale resolution. In the innovation and screening of new drugs or bioactive molecules, the activeness, the efficacy of the compound, and safety in biological systems are the main concerns on which determination of drug candidates is based. Further, drug discovery and screening of compounds are often performed in cell-based test systems in order to reduce costs and save time. Moreover, this system can provide more relevant results in in vivo studies, as well as high-throughput drug screening for various diseases during the early stages of drug discovery. Recently, MEMS technologies and integration with image detection techniques have been employed successfully. These new technologies and their possible ongoing transformations are addressed. Select reports are outlined, and not all the work that has been performed in the field of drug screening and development is covered. © 2014 Ramasamy et al.

Bennet D.,Gachon University | Kim S.,Gachon University | Kim S.,Graduate Gachon Medical Research Institute
Environmental Toxicology and Pharmacology | Year: 2014

A light radiation causes dysfunction and death of retinal cells and leads to degeneration. Present study, investigated the light-induced cell dysfunction, and their activity. Further, the effects of agmatine and resveratrol on light-induced damage and these underlying photo-oxidative and protective mechanisms were monitored by real-time bio-impedance system. After light exposure retinal ganglion cells underwent death in a time dependent manner. During light exposure the cells elevate free radicals and Ca2+, followed by nitric oxide (NO) and tumor necrosis factor-α (TNF-α), which can be facilitated to cell demise. The results revealed that these drugs can control the elevation of free radical, calcium gating, NO level, and increased TNF-α, which could diminish cell photo-damage. In summary, resveratrol helps more to rescue damaged cells compared to agmatine. The proposed system suggested mechanism could meet to identify the photo-toxic effects in retinal cells, and provides high throughput screening for early stages photo-damage. © 2014 Elsevier B.V.

Bennet D.,Gachon University | Kim S.,Gachon University | Kim S.,Graduate Gachon Medical Research Institute
Analyst | Year: 2015

Ultraviolet radiation (UVR) triggers many complex events in different types of skin cells, including benign, malignant and normal cells. Chromophores present in these cells play a crucial role in various cellular processes. Unprecedented methods are required for the real-time monitoring of changes in an in vitro model exposed to intermittent mild and intense UVR to determine the mechanisms underlying cell degeneration and the effects of unexpected toxic, agonist and antagonist agents. This study reports the analytical application of a whole cell-based sensor platform for examining the biophysical effects of UVR. We used human keratinocyte, melanocyte and fibroblast cell lines to determine the normal, pathological and protective roles of UVR. In addition, we examined the real-time morphological, biophysical and biomechanical changes associated with cell degeneration induced by UVR at 254 and 365 nm. Information on UVR-induced changes in the cytoskeleton ultrastructure, cellular integrity, cell spreading area, actin microfilament distribution inflammation, microtubule damage, membrane damage, rupture and death was characterized by examining the loss or increase in biophysical and biomechanical properties of these cells. All cells exposed to UVR at 254 and 365 nm showed a significant increase in surface roughness and stiffness in a time-dependent manner. UVR-induced toxicity in differently pigmented skin cells was compared with that in cells pretreated with melanin, keratin and basic fibroblast growth factor to analyze the shielding efficiency of these agents. Melanin exerted a significant shielding effect compared to the other two agents. The biophysical and biomechanical information obtained in this study could advance our understanding of the UVR-induced degeneration process, and help in developing new interventions strategies. © 2015 The Royal Society of Chemistry.

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