Quantification of doping state of redox sensitive nanoparticles for probing the invasiveness of cancer cells using surface enhanced Raman scattering

Redox activity is known to regulate migration, invasion, metastasis, proliferation, and vascularization of cancer. Because cancer is heterogeneous, the role of redox activity in different cancers and cancer-related processes vary widely. In this study, water soluble, Tween 80-coated polyaniline (TPAni) nanoparticles were synthesized and used as nano-agents for sensing the redox activities of various cancer cells. To identify the relationship between the redox activity and the aggressiveness of cancer cells, two different cancer cell lines, derived from the same tissue but different with regards to aggressiveness, were selected for study. First, the cancer cell lines were incubated with TPAni nanoparticles, and an absorbance ratio obtained from the cell culture media was used as a colorimetric indicator of the redox activities of the cells. Simultaneously, hydrophobically modified filter papers coated with silver nanosnowflakes (SNSF) were used as sensing substrates for surface enhanced Raman scattering (SERS). SERS spectra obtained from varying concentrations of rhodamine 6G were used to confirm the detection limit of the SNSF-based SERS substrate. Cell culture media containing TPAni nanoparticles were treated with the SNSF-containing SERS substrates to examine the redox activities of the various cancer cell lines.The redox activities of cancer cell lines were confirmed by absorbance spectral analysis, and these redox activities were better identified via an SERS analysis method. A SNSF-containing SERS substrate, fabricated from SNSF and filter paper, was used to sense redox activity in cancer cell lines and to further identify correlations between redox activity and cancer cell line aggressiveness, as indicated by the use of EpCAM as a biomarker. Finally, potential of ​in vivo ​redox activity sensing was also confirmed.ope

MR Weighted Image Discrimination by Artificial Intelligence

In this study, we proposed a method of learning neural networks by optimizing neural network input parameters to discern MRI-weighted images. To this end, we segmented the weighting domain of MRI. In feature extraction, the original image and segmented image were extracted by DWT, respectively. A neural network was trained by inputting extracted feature values. As a result of the experiment, it was found that the R-value of the segmented image is closer to 1 than the original image. The reason is that the images obtained by segmenting the areas of the weighted parts already have similarities. Also, it was found that the similarity between T1 and T2 weighted images is high in the same combination, and the similarity is relatively low in different weighted images. The most important issue in medical imaging is ensuring the confidence of radiologists using artificial intelligence. To solve this problem, it is of utmost importance that the algorithm developer and radiological A neural network was trained by inputting extracted feature values. As a result of the experiment, it was found that the R-value of the segmented image is closer to 1 than the original image. The reason is that the images obtained by segmenting the areas of the weighted parts already have similarities. Also, it was found that the similarity between T1 and T2 weighted images is high in the same combination, and the similarity is relatively low in different weighted images. The most important issue in medical imaging is ensuring the confidence of radiologists using artificial intelligence. To solve this problem, it is of utmost importance that the algorithm developer and radiological A neural network was trained by inputting extracted feature values. As a result of the experiment, it was found that the R-value of the segmented image is closer to 1 than the original image. The reason is that the images obtained by segmenting the areas of the weighted parts already have similarities. Also, it was found that the similarity between T1 and T2 weighted images is high in the same combination, and the similarity is relatively low in different weighted images. The most important issue in medical imaging is ensuring the confidence of radiologists using artificial intelligence. To solve this problem, it is of utmost importance that the algorithm developer and radiological technologist work together to provide a solution that is integrated with the radiologist's workflow.ope

Evaluation of Combined Contrast Agent using N-(p-maleimidophenyl) Isocyanate Linker-mediated Synthesis for Simultaneous PET-MRI

In this paper, a combined 18F-FDG(fluorodeoxyglucose) and MNP(magnetic nanoparticles) contrast agent was synthesized using N-(p-maleimidophenyl) isocyanate as the crosslinker for use in simultaneous PET-MRI scans. PET-MRI images were acquired and evaluated before and after injection of the combined contrast imaging agent (18F-FDG labeled MNP) from a glioma stem cell mouse model. After setting the region of interest (ROI) on each acquired image, the area of the lesion was calculated by segmentation. As a result, the PET image was larger than the MRI. In particular, the simultaneous PET-MRI images showed accurate lesions along with the surrounding soft tissue. The mean and standard deviation values were higher in the MRI images alone than in the PET images or the simultaneous PET-MRI images, regardless of whether the contrast agent was injected. In addition, the simultaneous PET-MRI image values were higher than for the PET images. For PSNR experiments, the original image was PET Image using 18F-FDG, MRI using MNPs, and MRI without contrast medium, and the target image was simultaneous PET-MRI image using 18F-FDG labeled MNPs contrast medium. As a result, all of them appeared significantly, suggesting that the 18F-FDG labeled MNPs contrast medium is useful. Future research is needed to develop an agent that can simultaneously diagnose and treat through SPECT-MRI imaging research that can use various nuclides.ope

T2-Weighted and Ultra-short TE Molecular Magnetic Resonance Imaging for Gastric Cancer Diagnosis using Polymer-based Magnetic Nanoparticles

Several recently developed technologies for molecular imaging have been applied to magnetic resonance (MR) imaging for cancer. In particular, various MR sequences with biocompatible polymer-based magnetic nanoparticles (pMNPs) have been applied for the MR imaging of cancer. However, there are several limitations to this approach, and passive contrast agents are not yet sufficiently targeted. This is a particular challenge for gastric cancer owing to the interference from stomach contents. Therefore, in this study we developed targeting contrast agent and assessed its feasibility for early gastric cancer diagnosis using a mouse model. Specifically, we synthesized pMNPs, which enable both T2-weighted (T2) and ultra-short TE (UTE) MR imaging using hyaluronic acid as the polymer, which binds to the receptor CD44, a recently identified biomarker of gastric cancer. Both MR sequences (T2, UTE) were analyzed with respect to imaging effects and targeting to the pMNPs. In vitro assessments showed no significant cytotoxicity of the pMNPs to MKN-45 and MKN-28 cells and confirmed the cellular uptake of the pMNPs. MR signal enhancement was identified after pMNPs injection to the mice, and the pMNPs gradually accumulated in the tumors. Based on the results, we suggest that pMNPs serve as useful probes for imaging stem-like cancer cells, and can further provide new possibilities by simultaneously confirming T1 and T2 MR imaging effects.ope

Inhibition of PD-L1 and tumor growth in triple-negative breast cancer using a magnetic nanovector with microRNA34a

BackgroundClinical applications of RNA interference for cancer treatment and immune therapy require the development of simultaneous therapy and imaging systems for microRNA. This research was performed to fabricate the miRNA34a-loaded magnetic nanoparticles and investigate its anticancer effects against triple-negative breast cancer (TNBC) in mice model.ResultsUsing two types of polymers to improve their water dispersibility and gene delivery, iron oxide magnetic nanoparticles were prepared for delivery of miRNA34a. The iron oxide magnetic nanoparticles were delivered to TNBC cells, and their efficacy was evaluated in vitro and in vivo. Delivery of miRNA34a reduced TNBC cell migration and decreased the expression of PD-L1 at the mRNA and protein levels. In animal experiments, delivery of miRNA34a reduced tumor growth, and immunostaining and algorithmic analysis confirmed the decrease in PD-L1 expression.ConclusionThis study is the first to modulate PD-L1 by delivering miRNA34a with magnetic nanoparticles, and the results suggest that miRNA34a can be delivered effectively using magnetic nanoparticles and has potential as a molecular imaging contrast agent.restrictio

Chitosan-based intelligent theragnosis nanocomposites enable pH-sensitive drug release with MR-guided imaging for cancer therapy

Smart drug delivery systems that are triggered by environmental conditions have been developed to enhance cancer therapeutic efficacy while limiting unwanted effects. Because cancer exhibits abnormally high local acidities compared to normal tissues (pH 7.4) due to Warburg effects, pH-sensitive systems have been researched for effective cancer therapy. Chitosan-based intelligent theragnosis nanocomposites, N-naphthyl-O-dimethymaleoyl chitosan-based drug-loaded magnetic nanoparticles (NChitosan-DMNPs), were developed in this study. NChitosan-DMNPs are capable of pH-sensitive drug release with MR-guided images because doxorubicin (DOX) and magnetic nanocrystals (MNCs) are encapsulated into the designed N-naphthyl-O-dimethymaleoyl chitosan (N-nap-O-MalCS). This system exhibits rapid DOX release as acidity increases, high stability under high pH conditions, and sufficient capacity for diagnosing and monitoring therapeutic responses. These results demonstrate that NChitosan-DMNPs have potential as theragnosis nanocomposites for effective cancer therapy.ope

Podoplanin-Targetable MR/OPTIC Dual-Mode Nanocomposites for Glioblastoma Multiforme in Mouse Brain Cancer

It is very desirable to design dual-mode nanocomposites for diagnostic applications via flexible strategies. Herein, we proposed to synthesize one type of multifunctional magnetic resonance (MR)/optic nanocomposites based on manganese ferrite magnetic nanoparticles (MFNPs) modified by fluorescent podoplanin (PDPN) antibodies. MFNPs were synthesized using a thermal decomposition method and were modified by the fluorescent PDPN antibodies on their surfaces. The fluorescent PDPN antibody-conjugated MFNPs enabled strong MR imaging and fluorescence imaging due to the antibodies that targeted brain tumors. These results demonstrate that MR/optic nanocomposites have potential as precision diagnostic systems for brain cancer.ope

CD44가 과발현된 마우스 위암모델에서 T2와 UTE시퀀스를 이용한 자기공명 분자영상

Graduate Program for Nanomedical Science/석사Novel diagnostic technique has been developed in many research area using targetable imaging contrast agents with MR sequence for cancer diagnosis. It is efficient for cancer diagnosis to use MR imaging both biocompatible targeting moiety and magnetic nanoparticle. Thus, we carried out that gastric cancer cell line which has stem like cancer cell property was injected in mouse model. Then, Both MR sequence (T2, UTE) for each imaging effects and targeting ability were analyzed into HA coated magnetic nanoparticle. We noted that MKN-45 cell which high-expressed CD44 ligand was showed contrast enhance efficiency through magnetic nanoparticle because of combining a lot of HA. MKN-28 cell (CD44 negative) which low-expressed CD44 ligand was showed less contrast enhance efficiency than MKN-45 cell. We find Ultra short TE sequence is better ability to distinguish tumor than now existing T2 sequence as imaging analysis for each. As a result, we suggest that HA coated magnetic nanoparticle is good probe for imaging of stem like cancer cell. Furthermore combination of T2 and UTE is good way as a tumor diagnosticprohibitio

司法 關聯 報道·論評의 自由와 限界에 關한 硏究

학위논문(석사)--서울대학교 대학원 :법학과 헌법전공,2003.Maste

벼베기 대민지원 장병들의 렙토스피라증 발생에 관한 혈청역학적 연구

학위논문(석사)--서울대학교 보건대학원 :보건학과 역학전공,1999.Maste