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#32764190   2020/08/07 To Up

The first visualization of chemotherapy-induced tumor apoptosis via magnetic particle imaging in a mouse model.

Imaging technologies that allow non-radiative visualization and quantification of apoptosis have a great potential for assessing therapy response, early diagnosis, and disease monitoring. Magnetic particle imaging (MPI), the direct imaging of magnetic nanoparticles as positive contrast agent and sole signal source, enables high image contrast (no tissue background signal), potential high sensitivity, and quantifiable signal intensity. These properties confer a great potential for application to tumor apoptosis monitoring. In this study, a simple and robust method was used to conjugate Alexa Fluor 647-AnnexinV (AF647-Anx), which can avidly bind to apoptotic cells, to superparamagnetic iron oxide (SPIO) nanoparticles, termed AF647-Anx-SPIO, which serves as an MPI-detectable tracer. Based on this apoptosis-specific tracer, MPI can accurately and unambiguously detect and quantify apoptotic tumor cells. AF647-Anx-SPIO showed relatively high affinity for apoptotic cells, and differences in binding between treated (apoptotic rate 67.21% ± 1.36%) and untreated (apoptotic rate 10.12 ± 0.11%) cells could be detected by MPI in vitro (P < 0.05). Moreover, the imaging signal was almost proportional to the number of apoptotic cells determined using an MPI scanner (R2 = 0.99). There was a greater accumulation of AF647-Anx-SPIO in tumors of drug-treated animals than in tumors of untreated animals (P < 0.05), and the difference could be detected by MPI ex vivo, while for in vivo imaging, no MPI imaging signal was detected in either group. Overall, this preliminary study demonstrates that MPI could be a potential imaging modality for tumor apoptosis imaging.
Xin Liang, Kun Wang, Jiangfeng Du, Jie Tian, Hui Zhang

1352 related Products with: The first visualization of chemotherapy-induced tumor apoptosis via magnetic particle imaging in a mouse model.

50 ul100 ul100 ug1 mg2 Pieces/Box100 μg100.00 ug100ug500

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#32760396   2020/07/14 To Up

Biomarkers in the Diagnosis and Prognosis of Sarcoidosis: Current Use and Future Prospects.

Sarcoidosis is a heterogeneous disease in terms of presentation, duration, and severity. Due to this heterogeneity, it is difficult to align treatment decisions. Biomarkers have proved to be useful for the diagnosis and prognosis of many diseases, and over the years, many biomarkers have been proposed to facilitate diagnosis, prognosis, and treatment decisions. Unfortunately, the ideal biomarker for sarcoidosis has not yet been discovered. The most commonly used biomarkers are serum and bronchoalveolar lavage biomarkers, but these lack the necessary specificity and sensitivity. In sarcoidosis, therefore, a combination of these biomarkers is often used to establish a proper diagnosis or detect possible progression. Other potential biomarkers include imaging tools and cell signaling pathways. Fluor-18-deoxyglucose positron emission tomography and high-resolution computed tomography have been proven to be more sensitive for the diagnosis and prognosis of both pulmonary and cardiac sarcoidosis than the serum biomarkers ACE and sIL-2R. There is an upcoming role for exploration of signaling pathways in sarcoidosis pathogenesis. The JAK/STAT and mTOR pathways in particular have been investigated because of their role in granuloma formation. The activation of these signaling pathways also proved to be a specific biomarker for the prognosis of sarcoidosis. Furthermore, both imaging and cell signaling biomarkers also enable patients who might benefit from a particular type of treatment to be distinguished from those who will not. In conclusion, the diagnostic and prognostic path of sarcoidosis involves many different types of existing and new biomarker. Research addressing biomarkers and disease pathology is ongoing in order to find the ideal sensitive and specific biomarker for this disease.
Raisa Kraaijvanger, Montse Janssen Bonás, Adriane D M Vorselaars, Marcel Veltkamp

1064 related Products with: Biomarkers in the Diagnosis and Prognosis of Sarcoidosis: Current Use and Future Prospects.

100ug2.5 mg100 mg1000 tests10 mg100ug500 MG50 ug 25 mg96T100ul

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#32749687   2020/08/04 To Up

Towards analyzing the potential of exosomes to deliver microRNA therapeutics.

Exosome selectivity mechanisms underlying exosome-target cell interactions and the specific traits affecting their capability to communicate still remain unclear. Moreover, the capacity of exosomes to efficiently deliver their molecular cargos intracellularly needs precise investigation towards establishing functional exosome-based delivery platforms exploitable in the clinical practice. The current study focuses on: (a) exosome production from normal MRC-5 and Vero cells growing in culture, (b) physicochemical characterization by dynamic light scattering (DLS) and cryo-transmission electron microscopy; (c) cellular uptake studies of rhodamine-labeled exosomes in normal and cancer cells, providing to exosomes either "autologous" or "heterologous" cellular delivery environments; and (d) loading exogenous Alexa Fluor 488-labeled siRNA into exosomes for the assessment of their delivering capacity by immunofluorescence in a panel of recipient cells. The data obtained thus far indicate that MRC-5 and Vero exosomes, indeed exhibit an interesting delivering profile, as promising "bio-shuttles," being pharmacologically exploitable in the context of theranostic applications.
Lefki-Pavlina N Giassafaki, Scheyla Siqueira, Emmanuel Panteris, Konstantina Psatha, Fani Chatzopoulou, Michalis Aivaliotis, Georgios Tzimagiorgis, Anette Müllertz, Dimitrios G Fatouros, Ioannis S Vizirianakis

1098 related Products with: Towards analyzing the potential of exosomes to deliver microRNA therapeutics.

100 25 ml Ready-to-use 200 1 module50 µg 100ul1 kit(96 Wells)

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#32733919   2020/07/08 To Up

Controlling Fibronectin Fibrillogenesis Using Visible Light.

We previously developed a surface-assisted assay to image early steps of cell-induced plasma fibronectin (FN) fibrillogenesis by timelapse atomic force microscopy (AFM). Unexpectedly, complementary attempts to visualize FN fibrillogenesis using fluorescently labeled FN (Alexa Fluor 488 or 568) and live-cell light microscopy initially failed consistently. Further analysis revealed that fibrillar remodeling was inhibited efficiently in the focal area illuminated during fluorescence imaging, but progressed normally elsewhere on the substrate, suggesting photo sensitivity of the FN fibrillogenesis process. In agreement, active cell-driven fibrillar extension of FN could be stopped by transient illumination with visible light during AFM timelapse scanning. Phototoxic effects on the cells could be ruled out, because pre-illuminating the FN layer before cell seeding also blocked subsequent fibrillar formation. Varying the illumination wavelength range between 400 and 640 nm revealed strong inhibition across the visible spectrum up to 560 nm, and a decreasing inhibitory effect at longer wavelengths. The photo effect also affected unlabeled FN, but was enhanced by fluorophore labeling of FN. The inhibitory effect could be reduced when reactive oxygen species (ROS) were removed for the cell imaging medium. Based on these findings, FN fibrillogenesis could be imaged successfully using a labeling dye with a long excitation wavelength (Alexa Fluor 633, excitation at 632 nm) and ROS scavengers, such as oxyrase, in the imaging medium. Fibrillar remodeling of exposed cell-free FN layers by AFM scanning required higher scan forces compared to non-exposed FN, consisting with mechanical stiffing of the FN layer after illumination. In agreement with changes in FN mechanics, cells spreading on pre-exposed FN showed reduced migration speeds, altered focal adhesion arrangement, and changes in mechanosensitive signaling pathways, including reduced FAK (Y397) and paxillin (Y118) phosphorylation. Pre-exposure of FN to visible light prior to cell seeding thus provides a useful tool to delineate mechanosensitive signaling pathway related to FN fibrillogenesis. When using FN-coated cell adhesion substrates, care should be taken when comparing experimental results obtained on non-exposed FN layers in cell culture incubators, or during live-cell fluorescence imaging, as FN fibrillogenesis and mechanosensitive cellular signaling pathways may be affected differently.
Tetyana Gudzenko, Clemens M Franz

1560 related Products with: Controlling Fibronectin Fibrillogenesis Using Visible Light.

1 ml1 mg1000 1 ml100ug 6 ml Ready-to-use 1mg100ug1 mg2 mg2 mL1 mg

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#32719532   2020/07/27 To Up

A general method to optimize and functionalize red-shifted rhodamine dyes.

Expanding the palette of fluorescent dyes is vital to push the frontier of biological imaging. Although rhodamine dyes remain the premier type of small-molecule fluorophore owing to their bioavailability and brightness, variants excited with far-red or near-infrared light suffer from poor performance due to their propensity to adopt a lipophilic, nonfluorescent form. We report a framework for rationalizing rhodamine behavior in biological environments and a general chemical modification for rhodamines that optimizes long-wavelength variants and enables facile functionalization with different chemical groups. This strategy yields red-shifted 'Janelia Fluor' (JF) dyes useful for biological imaging experiments in cells and in vivo.
Jonathan B Grimm, Ariana N Tkachuk, Liangqi Xie, Heejun Choi, Boaz Mohar, Natalie Falco, Kathy Schaefer, Ronak Patel, Qinsi Zheng, Zhe Liu, Jennifer Lippincott-Schwartz, Timothy A Brown, Luke D Lavis

1275 related Products with: A general method to optimize and functionalize red-shifted rhodamine dyes.

5500 mg10 mg1 module100 1 module1 mg1 kit100 mg100 µg

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#32707545   2020/07/24 To Up

Provision of rapid and specific ex vivo diagnosis of central nervous system lymphoma from rodent xenograft biopsies by a fluorescent aptamer.

Differentiating central nervous system (CNS) lymphoma from other intracranial malignancies remains a clinical challenge in surgical neuro-oncology. Advances in clinical fluorescence imaging contrast agents and devices may mitigate this challenge. Aptamers are a class of nanomolecules engineered to bind cellular targets with antibody-like specificity in a fraction of the staining time. Here, the authors determine if immediate ex vivo fluorescence imaging with a lymphoma-specific aptamer can rapidly and specifically diagnose xenografted orthotopic human CNS lymphoma at the time of biopsy.
Joseph Georges, Xiaodong Qi, Xiaowei Liu, Yu Zhou, Eric C Woolf, Amber Valeri, Zein Al-Atrache, Evgenii Belykh, Burt G Feuerstein, Mark Preul, Adrienne C Scheck, Mark Reiser, Trent Anderson, Jonas Gopez, Denah Appelt, Steven Yocom, Jennifer Eschbacher, Hao Yan, Peter Nakaji

1081 related Products with: Provision of rapid and specific ex vivo diagnosis of central nervous system lymphoma from rodent xenograft biopsies by a fluorescent aptamer.

50 UG 50 UG2.50 nmol1100ug Lyophilized

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#32698018   2020/07/15 To Up

Rational Design of Bioavailable Photosensitizers for Manipulation and Imaging of Biological Systems.

Light-mediated chemical reactions are powerful methods for manipulating and interrogating biological systems. Photosensitizers, compounds that generate reactive oxygen species upon excitation with light, can be utilized for numerous biological experiments, but the repertoire of bioavailable photosensitizers is limited. Here, we describe the synthesis, characterization, and utility of two photosensitizers based upon the widely used rhodamine scaffold and demonstrate their efficacy for chromophore-assisted light inactivation, cell ablation in culture and in vivo, and photopolymerization of diaminobenzidine for electron microscopy. These chemical tools will facilitate a broad range of applications spanning from targeted destruction of proteins to high-resolution imaging.
Thomas C Binns, Anthony X Ayala, Jonathan B Grimm, Ariana N Tkachuk, Guillaume A Castillon, Sebastien Phan, Lixia Zhang, Timothy A Brown, Zhe Liu, Stephen R Adams, Mark H Ellisman, Minoru Koyama, Luke D Lavis

2020 related Products with: Rational Design of Bioavailable Photosensitizers for Manipulation and Imaging of Biological Systems.

5 G100.00 ul 25 G96 Well25 µg10 mg100μg 5 lt 1 kit(s) 5L500 mg

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#32673369   2020/07/16 To Up

A portable and high-sensitivity optical sensing system for detecting fluorescently labeled enterohaemorrhagic Escherichia coli Shiga toxin 2B-subunit.

We developed a stand-alone, real-time optical detection device capable of reading fluorescence intensities from cell samples with high sensitivity and precision, for use as a portable fluorescent sensor for sensing fluorescently labeled enterohemorrhagic Escherichia coli (EHEC) Shiga toxins (Stxs). In general, the signal intensity from the fluorescently labeled Stxs was weak due to the small number of molecules bound to each cell. To address this technical challenge, we used a highly sensitive light detector (photomultiplier tube: PMT) to measure fluorescence, and designed a portable optical housing to align optical parts precisely; the housing itself was fabricated on a 3D printer. In addition, an electric circuit that amplified PMT output was designed and integrated into the system. The system shows the toxin concentration in the sample on a liquid crystal display (LCD), and a microcontroller circuit is used to read PMT output, process data, and display results. In contrast to other portable fluorescent detectors, the system works alone, without any peripheral computer or additional apparatus; its total size is about 17 × 13 × 9 cm3, and it weighs about 770 g. The detection limit was 0.01 ppm of Alexa Fluor 488 in PBS, which is ten thousand times lower than those of other smartphone-based systems and sufficiently sensitive for use with a portable optical detector. We used the portable real-time optical sensing system to detect Alexa Fluor 488-tagged Stx2B-subunits bound to monocytic THP-1 cells expressing the toxin receptor globotriaosylceramide (Gb3). The device did not detect a signal from Gb3-negative PD36 cells, indicating that it was capable of specifically detecting Stxs bound to cells expressing the toxin receptor. Following the development of a rapid and autonomous method for fluorescently tagging cells in food samples, the optical detection system described here could be used for direct detection of Shiga toxins in food in the field.
Jeongtae Kim, Jun-Young Park, Young-Jun Park, Seo-Young Park, Moo-Seung Lee, Chiwan Koo

2020 related Products with: A portable and high-sensitivity optical sensing system for detecting fluorescently labeled enterohaemorrhagic Escherichia coli Shiga toxin 2B-subunit.

100 96 tests100ug100 100 200 200 100 100 ug100

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#32659511   2020/07/10 To Up

Nanobody click chemistry for convenient site-specific fluorescent labelling, single step immunocytochemistry and delivery into living cells by photoporation and live cell imaging.

While conventional antibodies have been an instrument of choice in immunocytochemistry for some time, their small counterparts known as nanobodies have been much less frequently used for this purpose. In this study we took advantage of the availability of nanobody cDNAs to site-specifically introduce a non-standard amino acid carrying an azide/alkyne moiety, allowing subsequent Cu(I)-catalyzed Azide-Alkyne Click Chemistry (CuAAC). This generated a fluorescently labelled nanobody that can be used in single step immunocytochemistry as compared to conventional two step immunocytochemistry. Two strategies were explored to label nanobodies with Alexa Fluor 488. The first involved enzymatic addition of an alkyne-containing peptide to nanobodies using sortase A, while the second consisted of incorporating para-azido phenylalanine at the nanobody C-terminus. Through these approaches, the fluorophore was covalently and site-specifically attached. It was demonstrated that cortactin and β-catenin, cytoskeletal and adherens junction proteins respectively, can be imaged in cells in this manner through single step immunocytochemistry. However, fixation and permeabilization of cells can alter native protein structure and form a dense cross-linked protein network, encumbering antibody binding. It was shown that photoporation prior to fixation not only allowed delivery of nanobodies into living cells, but also facilitated β-catenin nanobody Nb86 imaging of its target, which was not possible in fixed cells. Pharmacological inhibitors are lacking for many non-enzymatic proteins, and it is therefore expected that new biological information will be obtained through photoporation of fluorescent nanobodies, which allows the study of short term effects, independent of gene-dependent (intrabody) expression.
Tim Hebbrecht, Jing Liu, Olivier Zwaenepoel, Gaëlle Boddin, Chloé Van Leene, Klaas Decoene, Annemieke Madder, Kevin Braeckmans, Jan Gettemans

1763 related Products with: Nanobody click chemistry for convenient site-specific fluorescent labelling, single step immunocytochemistry and delivery into living cells by photoporation and live cell imaging.

1.00 flask1.00 flask1.00 flask

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#32648544   2020/07/10 To Up

Real-time in vivo imaging of extracellular ATP in the brain with a hybrid-type fluorescent sensor.

Adenosine 5' triphosphate (ATP) is a ubiquitous extracellular signaling messenger. Here, we describe a method for in-vivo imaging of extracellular ATP with high spatiotemporal resolution. We prepared a comprehensive set of cysteine-substitution mutants of ATP-binding protein, FoF-ATP synthase ε subunit, labeled with small-molecule fluorophores at the introduced cysteine residue. Screening revealed that the Cy3-labeled glutamine-105 mutant (Q105C-Cy3; designated ATPOS) shows a large fluorescence change in the presence of ATP, with submicromolar affinity, pH-independence, and high selectivity for ATP over ATP metabolites and other nucleotides. To enable in-vivo validation, we introduced BoNT/C-Hc for binding to neuronal plasma membrane and Alexa Fluor 488 for ratiometric measurement. The resulting ATPOS complex binds to neurons in cerebral cortex of living mice, and clearly visualized a concentrically propagating wave of extracellular ATP release in response to electrical stimulation. ATPOS should be useful to probe the extracellular ATP dynamics of diverse biological processes in vivo.
Nami Kitajima, Kenji Takikawa, Hiroshi Sekiya, Kaname Satoh, Daisuke Asanuma, Hirokazu Sakamoto, Shodai Takahashi, Kenjiro Hanaoka, Yasuteru Urano, Shigeyuki Namiki, Masamitsu Iino, Kenzo Hirose

2956 related Products with: Real-time in vivo imaging of extracellular ATP in the brain with a hybrid-type fluorescent sensor.

96 tests2596 tests2596 tests2596 tests2596T

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