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Li S, Jiang J, Zhu W, Wang D, Dong C, Bu Y, Zhang J, Gao D, Hu X, Wan C. Increased cell-free DNA is associated with oxidative damage in patients with schizophrenia. J Psychiatr Res 2024; 175:20-28. [PMID: 38701608 DOI: 10.1016/j.jpsychires.2024.04.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/31/2024] [Accepted: 04/25/2024] [Indexed: 05/05/2024]
Abstract
Cell-free DNA (cfDNA) has been found to be elevated in patients with schizophrenia (SZ), potentially derived from activated apoptosis, but the underlying mechanisms remain unknown. Moreover, whether the concentrations of cfDNA are altered with disease stage has not been investigated, which limits its clinical application as an auxiliary diagnostic marker for SZ. Using an improved fluorescence correlation spectroscopy (FCS) method that does not require DNA extraction, we measured the molar concentrations of cfDNA in plasma samples of 191 patients with SZ, 78 patients with mood disorders (MD) and 65 healthy controls (HC). We also analyzed the cfDNA composition from either the nucleus or mitochondria, oxidation markers and biochemical indexes to explore the potential mechanistic associations of the increased cfDNA levels. We found that in SZ patients, the cfDNA levels were significantly increased (P = 0.003) regardless of the different disease stages or antipsychotic medication use. Furthermore, qPCR revealed that cell-free nuclear DNA (cf-nDNA) (P = 0.041) but not cell-free mitochondrial DNA (cf-mtDNA) was elevated in SZ patients. Moreover, decreased SOD activity in SZ patients (P = 0.005) was negatively correlated with cfDNA levels (P = 0.047), and fasting blood glucose was positively correlated with cfDNA levels in SZ patients (P = 0.013). Our study provides evidence to support that the elevated cfDNA may be a convenient, effective and stable trait indicator of SZ. Further analysis showed that it mainly came from nucleus, suggesting increased apoptosis, and potentially related to oxidative stress and high blood glucose levels in patients.
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Affiliation(s)
- Shuhui Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Jie Jiang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Wenli Zhu
- The Fourth People's Hospital of Wuhu, Wuhu, 241003, China
| | - Dandan Wang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Chaoqing Dong
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yangying Bu
- The Fourth People's Hospital of Wuhu, Wuhu, 241003, China
| | - Juan Zhang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Daiyutong Gao
- Department of Mathematics, Nanjing University, Nanjing, 210093, China
| | - Xiaowen Hu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China.
| | - Chunling Wan
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China; Shanghai Mental Health Center, Shanghai Key Laboratory of Psychiatry Disorders, Shanghai Jiao Tong University, Shanghai, 200030, China.
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2
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Dong C, Ren J. Resonance Light-Scattering Correlation Spectroscopy and Its Application in Analytical Chemistry for Life Science. Acc Chem Res 2023; 56:2582-2594. [PMID: 37706459 DOI: 10.1021/acs.accounts.3c00306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Resonance light-scattering correlation spectroscopy (RLSCS) is a new single-particle detection method with its working principle being like fluorescence correlation spectroscopy (FCS). RLSCS is obtained by autocorrelation function analysis on the measured fluctuation of the resonance light scattering (RLS) intensity occurring within a subfemtoliter volume when a single nanoparticle (such as gold nanoparticles (NPs) or silver (SNPs)) freely diffuses through the volume. The RLSCS technique can detect such parameters as concentration, diffusion coefficient (translation and rotation), etc. Compared with the FCS technique, the correlated fluorescence intensity signal in RLSCS is replaced with the RLS signal of the nanoparticles, overcoming some limits of the fluorescent probes such as photobleaching under high-intensity or long-term illumination. In this Account, we showcase RLSCS methods, theoretical models at different optical configurations, and some key applications. First, the RLSCS optical detection system was constructed based on the confocal optics, its theoretical model was proposed, and the diffusion behaviors of the nanoparticles in the solution were studied including the rotational and translational diffusion. And, methods were developed to measure the concentration, size, aspect ratio, and size distribution of the NPs. Second, based on the RLSCS methods, some detection strategies were developed for homogeneous DNA detection, immunoassay, apoptosis assay, self-thermophoresis of the nanomotor, and quantitative assay in single living cells. Meanwhile, a new fluorescence/scattering cross-correlation spectroscopy (FSCCS) method was proposed for monitoring the molecule-particle interaction. This method enriched the conventional fluorescence/fluorescence cross-correlation spectroscopy (FCCS) method. Third, using the EMCCD with high sensitivity and rapid response as an optical detector, two temporospatially resolved scattering correlation spectroscopy methods and their theoretical models were developed: total internal reflection (TIR) configuration-based spatially resolved scattering correlation spectroscopy (SRSCS) and dark-field illumination-based scattering correlation spectroscopy (DFSCS). These methods extended single-spot confocal RLSCS to imaging RLSCS, which makes RLSCS have the ability for multiple channel detection with temporospatial resolution. The method was successfully used for investigating the dynamic behaviors of gold NPs in live cells and obtained its temporospatial concentration distribution and diffusion behaviors. The final section of this Account outlines future directions in the development of RLSCS.
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Affiliation(s)
- Chaoqing Dong
- School of Chemistry and Chemical Engineering, Frontiers Science Centre for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Jicun Ren
- School of Chemistry and Chemical Engineering, Frontiers Science Centre for Transformative Molecules, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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Liu J, Chen H, Wang B, Luo Y, Yang G, Zhang S, Li S. Triarylboron-Based High Photosensitive Probes for Apoptosis Detection, Tumor-Targeted Imaging, and Selectively Inducing Apoptosis of Tumor Cells by Photodynamics. Anal Chem 2022; 94:8483-8488. [PMID: 35635074 DOI: 10.1021/acs.analchem.2c01364] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Herein, a series of triarylboron-based fluorescent probes were developed for distinguishing apoptosis from living cells and even necrosis. They also demonstrate high photosensitivity because they can produce detectable reactive oxygen species (ROS) under an ultra-low light power density (1.5 mW/cm2). By changing the peripheral groups to regulate the performance, we identified a multifunctional probe, TAB-6-amyl, which can be used not only for selectively imaging apoptosis but also for the targeted imaging of SKOV-3 cells in vitro and in vivo. It could further specifically induce the apoptosis of SKOV-3 cells under light irradiation. During the study, we also found that TAB-6-amyl can cross the blood-brain barrier (BBB). Therefore, another probe based on this kind of structure, TAB-5-M-1-cRGD, was constructed for the targeted imaging of brain glioma cells and inducing their apoptosis. This study offers some promising tools for apoptosis detection and tumor photodynamic therapy (PDT).
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Affiliation(s)
- Jun Liu
- School of Pharmacy and Institute of Pharmacy, North Sichuan Medical College, Sichuan 637100, China
| | - Hongyu Chen
- Thyroid and Breast Surgery, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, People's Republic of China
| | - Bing Wang
- School of Pharmacy and Institute of Pharmacy, North Sichuan Medical College, Sichuan 637100, China
| | - Yingping Luo
- School of Pharmacy and Institute of Pharmacy, North Sichuan Medical College, Sichuan 637100, China
| | - Guoqiang Yang
- Institute of Chemistry & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Shilu Zhang
- School of Pharmacy and Institute of Pharmacy, North Sichuan Medical College, Sichuan 637100, China
| | - Shayu Li
- College of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
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Shamsipur M, Chabok A, Molaabasi F, Seyfoori A, Hajipour-Verdom B, Shojaedin-Givi B, Sedghi M, Naderi-Manesh H, Yeganeh-Faal A. Label free phosphate functionalized semiconducting polymer dots for detection of iron(III) and cytochrome c with application to apoptosis imaging. Biosens Bioelectron 2019; 141:111337. [DOI: 10.1016/j.bios.2019.111337] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/06/2019] [Accepted: 05/17/2019] [Indexed: 01/17/2023]
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5
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Su D, Hou Y, Dong C, Ren J. Fluctuation correlation spectroscopy and its applications in homogeneous analysis. Anal Bioanal Chem 2019; 411:4523-4540. [DOI: 10.1007/s00216-019-01884-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 04/12/2019] [Accepted: 04/29/2019] [Indexed: 12/11/2022]
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Ruan L, Ge M, Huang X, Ren J. Assay of Single-Cell Apoptosis by Ensemble and Single-Molecule Fluorescence Methods: Annexin-V/Polyethylene Glycol-Functionalized Quantum Dots as Probes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10040-10047. [PMID: 30063356 DOI: 10.1021/acs.langmuir.8b01749] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Apoptosis plays a critical role in many biological processes and the etiology of various diseases of the immune system. The study of apoptosis would allow both improving the diagnosis of certain diseases and serving as a target of drug screening. In this paper, we developed a sensitive assay of single-cell apoptosis using semiconductor quantum dots (QDs) as fluorescent-labeling probes. The principle of this assay is based on the detection of phosphatidylserine (PS) exposed on the plasma membrane during the drug-induced apoptosis. The QD-labeled annexin V (AV) was prepared to specifically target PS on the membrane of apoptotic cells, and PS was detected by fluorescent imaging, flow cytometer, and single-molecule fluorescence correlation spectroscopy (FCS). We developed the procedures for conjugation of QDs to AV and for purification of their conjugates by gel chromatography. The obtained conjugates were characterized by FCS, capillary electrophoresis, and zeta potential analyzer. We studied the nonspecific adsorption of cells to different surface-modified QDs and found that the nonspecific adsorption effects were significantly reduced by modification of QDs with polyethylene glycol in the detection of apoptosis. In this assay, the results obtained by flow cytometry were consistent with the commercial test kit. Furthermore, a home-built single-molecule FCS system was developed for in situ study the drug-induced apoptosis. We observed the significant change in the diffusion coefficients of QDs on cells during the progress of cell apoptosis. Compared with conventional methods, the fluorescent methods represented here possess high sensitivity because of the use of high photo stability and brightness QDs as labeling probes and provide the temp-spatial information on a single apoptotic cell.
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Affiliation(s)
- Lingao Ruan
- School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , People's Republic of China
- Shanghai Laiyi Center for Biopharmaceutical R&D , 200 Niudun Road , Shanghai 201203 , People's Republic of China
| | - Mei Ge
- Shanghai Laiyi Center for Biopharmaceutical R&D , 200 Niudun Road , Shanghai 201203 , People's Republic of China
| | - Xiangyi Huang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , People's Republic of China
| | - Jicun Ren
- School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , People's Republic of China
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7
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Jing R, Wang H, Ju S, Cui M. Reference materials for molecular diagnostics: Current achievements and future strategies. Clin Biochem 2018; 56:11-17. [DOI: 10.1016/j.clinbiochem.2018.04.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 04/08/2018] [Accepted: 04/17/2018] [Indexed: 02/06/2023]
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8
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Analysis of the concentrations and size distributions of cell-free DNA in schizophrenia using fluorescence correlation spectroscopy. Transl Psychiatry 2018; 8:104. [PMID: 29795286 PMCID: PMC5966419 DOI: 10.1038/s41398-018-0153-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 01/05/2023] Open
Abstract
Cell-free DNA (cfDNA), which is primarily released following cell death, has been described and developed to serve as an effective biomarker in autoimmune diseases which may share the pathogenesis with schizophrenia. In this study, we hypothesized and explored whether the concentrations and size distributions of cfDNA are abnormal in schizophrenia. A total of 65 patients with schizophrenia (SZ), 29 patients with mood disorders (MD) and 62 matched healthy controls (HC) were included in the study. Fluorescence correlation spectroscopy was used to assay the molar concentrations and size distributions of cfDNA. Fluorometric quantification and quantitative real-time PCR (qPCR) were performed to verify the results. The cfDNA levels were approximately two-fold higher in the SZ group ((29 ± 15) nM) than in the healthy controls ((15 ± 9) nM; P-value = 0.00062), but the levels in patients with MD were not significantly different from those in the healthy controls ((17 ± 10) nM; P-value = 0.343). According to the size distribution analysis, cfDNA in schizophrenia patients was composed of shorter DNA molecules and showed an apoptosis-like distribution pattern. Our study shows the elevated levels and short sizes of cfDNA in schizophrenia patients, which provide direct evidences supporting increased apoptotic activity in the disease. cfDNA may be developed to serve as an auxiliary diagnostic marker for the disease in the future.
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9
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Molecular insights for the biological interactions between polyethylene glycol and cells. Biomaterials 2017; 147:1-13. [DOI: 10.1016/j.biomaterials.2017.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/18/2017] [Accepted: 09/02/2017] [Indexed: 12/13/2022]
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10
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Zhang B, Liu H, Huang X, Dong C, Ren J. Size Distribution of Nanoparticles in Solution Characterized by Combining Resonance Light Scattering Correlation Spectroscopy with the Maximum Entropy Method. Anal Chem 2017; 89:12609-12616. [DOI: 10.1021/acs.analchem.7b04166] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bocheng Zhang
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Heng Liu
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Xiangyi Huang
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Chaoqing Dong
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Jicun Ren
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
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11
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Li J, Dong C, Ren J. Strategies to reduce detection volume of fluorescence correlation spectroscopy (FCS) to realize physiological concentration measurements. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Ruan L, Su D, Shao C, Wang J, Dong C, Huang X, Ren J. A sensitive and microscale method for drug screening combining affinity probes and single molecule fluorescence correlation spectroscopy. Analyst 2015; 140:1207-14. [DOI: 10.1039/c4an01816h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The theoretical model of drug screening method based on competitive reaction and fluorescence correlation spectroscopy.
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Affiliation(s)
- Lingao Ruan
- College of Chemistry & Chemical Engineering
- State Key Laboratory of Metal Matrix Composites
- Shanghai Jiaotong University
- Shanghai 200240
- People's Republic of China
| | - Di Su
- College of Chemistry & Chemical Engineering
- State Key Laboratory of Metal Matrix Composites
- Shanghai Jiaotong University
- Shanghai 200240
- People's Republic of China
| | - Chang Shao
- Shanghai Laiyi Center for Biopharmaceutical R&D
- Shanghai 201203
- People's Republic of China
| | - Jinjie Wang
- College of Chemistry & Chemical Engineering
- State Key Laboratory of Metal Matrix Composites
- Shanghai Jiaotong University
- Shanghai 200240
- People's Republic of China
| | - Chaoqing Dong
- College of Chemistry & Chemical Engineering
- State Key Laboratory of Metal Matrix Composites
- Shanghai Jiaotong University
- Shanghai 200240
- People's Republic of China
| | - Xiangyi Huang
- College of Chemistry & Chemical Engineering
- State Key Laboratory of Metal Matrix Composites
- Shanghai Jiaotong University
- Shanghai 200240
- People's Republic of China
| | - Jicun Ren
- College of Chemistry & Chemical Engineering
- State Key Laboratory of Metal Matrix Composites
- Shanghai Jiaotong University
- Shanghai 200240
- People's Republic of China
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13
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Qu Y, Li J, Ren J, Leng J, Lin C, Shi D. Enhanced magnetic fluid hyperthermia by micellar magnetic nanoclusters composed of Mn(x)Zn(1-x)Fe(2)O(4) nanoparticles for induced tumor cell apoptosis. ACS APPLIED MATERIALS & INTERFACES 2014; 6:16867-79. [PMID: 25204363 DOI: 10.1021/am5042934] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Monodispersed MnxZn1-xFe2O4 magnetic nanoparticles of 8 nm are synthesized and encapsulated in amphiphilic block copolymer for development of the hydrophilic magnetic nanoclusters (MNCs). These MNCs exhibit superparamagnetic characteristics, high specific absorption rate (SAR), large saturation magnetization (Ms), excellent stability, and good biocompatibility. MnFe2O4 and Mn0.6Zn0.4Fe2O4 are selected as optimum compositions for the MNCs (MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC) and employed for magnetic fluid hyperthermia (MFH) in vitro. To ensure biosafety of MFH, the parameters of alternating magnetic field (AMF) and exposure time are optimized with low frequency, f, and strength of applied magnetic field, Happlied. Under optimized conditions, MFH of MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC result in cancer cell death rate up to 90% within 15 min. The pathway of cancer cell death is identified as apoptosis, which occurs in mild hyperthermia near 43 °C. Both MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC show similar efficiencies on drug-sensitive and drug-resistant cancer cells. On the basis of these findings, those MnxZn1-xFe2O4 nanoclusters can serve as a promising candidate for effective targeting, diagnosis, and therapy of cancers. The multimodal cancer treatment is also possible as amphiphilic block copolymer can encapsulate, in a similar fashion, different nanoparticles, hydrophobic drugs, and other functional molecules.
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Affiliation(s)
- Yang Qu
- Institute of Nano and Biopolymeric Materials, School of Materials Science and Engineering, Tongji University , 4800 Caoan Road, Shanghai 201804, China
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14
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Coupling of fluorescence correlation spectroscopy with capillary and microchannel analytical systems and its applications. Electrophoresis 2014; 35:2267-78. [DOI: 10.1002/elps.201300648] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 03/10/2014] [Accepted: 03/21/2014] [Indexed: 02/03/2023]
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15
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Chemiluminescent detection of cell apoptosis enzyme by gold nanoparticle-based resonance energy transfer assay. Anal Bioanal Chem 2014; 406:5677-84. [PMID: 24481623 DOI: 10.1007/s00216-013-7611-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/27/2013] [Accepted: 12/30/2013] [Indexed: 10/25/2022]
Abstract
We report a new chemiluminescence resonance energy transfer (CRET) technique, using gold nanoparticles (AuNPs) as efficient energy acceptor, for homogeneous measurement of cell apoptosis enzyme with high sensitivity. In the design of the CRET system, we chose the highly sensitive chemiluminescence (CL) reaction between luminol and hydrogen peroxide catalysed by horseradish peroxidase (HRP) because the CL spectrum of luminol (λ max 425 nm) partially overlaps the visible absorption bands of AuNPs. In this system, the peptide substrate (DEVD) of caspase 3 was linked to the AuNP surface by Au-S linkage. HRP was attached to the AuNP surface by means of a bridge formed by the streptavidin-biotin reaction. CRET occurred as a result of formation of AuNP-peptide-biotin-streptavidin-HRP complexes. The CL of luminol was significantly reduced, because of the quenching effect of AuNPs. The quenched CL was recovered after cleavage of DEVD by caspase 3, an enzyme involved in the apoptotic process. Experimental conditions were systematically investigated. Under the optimum conditions the increase of the CL signal was linearly dependent on caspase 3 concentration within the concentration range 25 pmol L(-1) to 800 pmol L(-1) and the detection limit of caspase 3 was as low as 20 pmol L(-1), one order of magnitude lower than for FRET sensors based on graphene oxides. Our method was successfully used to detect drug-induced apoptosis of cells. This approach is expected to be extended to other assays, i.e., using other enzymes, analytes, CL substances, and even other nanoparticles (e.g., quantum dots and graphene).
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Iyer D, Ray RD, Pappas D. High temporal resolution fluorescence measurements of a mitochondrial dye for detection of early stage apoptosis. Analyst 2013; 138:4892-7. [PMID: 23831722 DOI: 10.1039/c3an01142a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the present study, early stage apoptosis is explored with high temporal resolution. In addition to monitoring early apoptosis induction in single cells by ultrasensitive confocal fluorescence microscopy (UCFM), the mitochondrial protein release kinetics was explored. The current study shows development and optimization of a novel, rapid apoptosis assay to explore the earliest changes in cells by the intrinsic apoptosis pathway. We show that early apoptotic changes in the mitochondria begin nearly simultaneously with the addition of an apoptosis-inducing drug, such as staurosporine. With a temporal resolution of five minutes, this non-invasive analytical technique can elucidate the earliest apoptotic events in living cells. Moreover, our results show that the mitochondrial inter-membrane proteins are not involved in the extrinsic pathway of Ramos cells mediated by an anti-CD95 antibody. Additional techniques such as light microscopy and flow cytometry were employed to confirm the results obtained by ultrasensitive confocal fluorescence microscopy. The results of this study help to understand the earliest mechanisms of apoptosis induction in cells, enabling new methods of drug testing and dose-response analyses.
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Affiliation(s)
- Divya Iyer
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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