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1.
Jongeun Kang Eunha Hwang Hyunseung Lee Mi Young Cho Sanu Karan Hak Nam Kim Jong Seung Kim Jonathan L. Sessler Sankarprasad Bhuniya Kwan Soo Hong 《Molecules (Basel, Switzerland)》2021,26(7)
We have synthesized new magnetic resonance imaging (MRI) T1 contrast agents (CA1 and CA2) that permit the activatable recognition of the cellular vicinal thiol motifs of the protein thioredoxin. The contrast agents showed MR relaxivities typical of gadolinium complexes with a single water molecule coordinated to a Gd3+ center (i.e., ~4.54 mM−1s−1) for both CA1 and CA2 at 60 MHz. The contrast agent CA1 showed a ~140% relaxivity enhancement in the presence of thioredoxin, a finding attributed to a reduction in the flexibility of the molecule after binding to thioredoxin. Support for this rationale, as opposed to one based on preferential binding, came from 1H-15N-HSQC NMR spectral studies; these revealed that the binding affinities toward thioredoxin were almost the same for both CA1 and CA2. In the case of CA1, T1-weighted phantom images of cancer cells (MCF-7, A549) could be generated based on the expression of thioredoxin. We further confirmed thioredoxin expression-dependent changes in the T1-weighted contrast via knockdown of the expression of the thioredoxin using siRNA-transfected MCF-7 cells. The nontoxic nature of CA1, coupled with its relaxivity features, leads us to suggest that it constitutes a first-in-class MRI T1 contrast agent that allows for the facile and noninvasive monitoring of vicinal thiol protein motif expression in live cells. 相似文献
2.
Sankar Prasad Bhuniya Safikur Rahman Anshul J. Satyanand Mahendrasinh M. Gharia Ashok M. Dave 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1650-1658
Maize starch was modified by allyl chloride adopting an interfacial reaction technique with cetyltrimethyl ammonium bromide as a phase‐transfer catalyst and pyridine as an acid acceptor. The degree of substitution was determined from an increasing carbon content of the modified starch. The percentage of carbon and hydrogen of the allyl‐modified starch was estimated by elemental analysis (C, H, and N), and the product characterization was done through 1H NMR and 13C NMR analyses. The allyl‐modified starch was then copolymerized with methacrylic acid and a combination of methacrylic acid and acrylamide at 50 and 70 °C with potassium persulfate as an initiator. The copolymer thus formed swelled in distilled water after neutralization with sodium carbonate. The percentage of absorption capacity of the hydrogels was determined with distilled water and 0.9% NaCl solution. The highest percentage of absorption, 6500%, was achieved for the developed hydrogel containing allyl starch and acrylic monomer in a 1.7:1 w/w ratio and acrylic monomer, namely, methacrylic acid and acrylamide in a 3.2:1 w/w ratio. The study on biodegradability of the developed hydrogel showed that the hydrogel is degradable in the presence of diastase (amylase). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1650–1658, 2003 相似文献
3.
Homochiral bis(oxazolinyl)pyridine type ligands were synthesized from (S)-valine and converted into their Cu(II) complexes. Reduction of these Cu(II) complexes into Cu(I) with diazoesters was studied by uv-vis and epr spectroscopy. The enantioselective cyclopropanation reaction was carried out using styrene as a model substrate. 相似文献
4.
Lee MH Kim JY Han JH Bhuniya S Sessler JL Kang C Kim JS 《Journal of the American Chemical Society》2012,134(30):12668-12674
Presented here is a multicomponent synthetic strategy that allows for the direct, fluorescence-based monitoring of the targeted cellular uptake and release of a conjugated therapeutic agent. Specifically, we report here the design, synthesis, spectroscopic characterization, and preliminary in vitro biological evaluation of a RGD peptide-appended naphthalimide pro-CPT (compound 1). Compound 1 is a multifunctional molecule composed of a disulfide bond as a cleavable linker, a naphthalimide moiety as a fluorescent reporter, an RGD cyclic peptide as a cancer-targeting unit, and camptothecin (CPT) as a model active agent. Upon reaction with free thiols in aqueous media at pH 7.4, disulfide cleavage occurs. This leads to release of the free CPT active agent, as well as the production of a red-shifted fluorescence emission (λ(max) = 535 nm). Confocal microscopic experiments reveal that 1 is preferentially taken up by U87 cells over C6 cells. On the basis of competition experiments involving okadaic acid, an inhibitor of endocytosis, it is concluded that uptake takes place via RGD-dependent endocytosis mechanisms. In U87 cells, the active CPT payload is released within the endoplasmic reticulum, as inferred from fluorescence-based colocalization studies using a known endoplasmic reticulum-selective dye. The present drug delivery system (DDS) could represent a new approach to so-called theragnostic agent development, wherein both a therapeutic effect and drug uptake-related imaging information are produced and can be readily monitored at the subcellular level. In due course, the strategy embodied in conjugate 1 could allow for more precise monitoring of dosage levels, as well as an improved understanding of cellular uptake and release mechanisms. 相似文献
5.
We generalize the notion of k-radical of Green’s \({\overline{\mathcal{J}}}\)-relation, study the decompositions of semirings and investigate the semirings on which the powers and transitive closures of k-radicals are distributive lattice congruences. 相似文献
6.
Soo Yeon Kim Arup Podder Hyunseung Lee Youn-Joo Cho Eun Hee Han Sabina Khatun Jonathan L. Sessler Kwan Soo Hong Sankarprasad Bhuniya 《Chemical science》2020,11(36):9875
Abnormal anaerobic metabolism leads to a lowering of the pH of many tumours, both within specific intracellular organelles and in the surrounding extracellular regions. Information relating to pH-fluctuations in cells and tissues could aid in the identification of neoplastic lesions and in understanding the determinants of carcinogenesis. Here we report an amphiphilic fluorescent pH probe (CS-1) that, as a result of its temporal motion, provides pH-related information in cancer cell membranes and selected intracellular organelles without the need for specific tumour targeting. Time-dependent cell imaging studies reveal that CS-1 localizes within the cancer cell-membrane about 20 min post-incubation. This is followed by migration to the lysosomes at 30 min before being taken up in the mitochondria after about 60 min. Probe CS-1 can selectively label cancer cells and 3D cancer spheroids and be readily observed using the green fluorescence channel (λem = 532 nm). In contrast, CS-1 only labels normal cells marginally, with relatively low Pearson''s correlation coefficients being found when co-incubated with standard intracellular organelle probes. Both in vivo and ex vivo experiments provide support for the suggestion that CS-1 acts as a fluorescent label for the periphery of tumours, an effect ascribed to proton-induced aggregation. A much lower response is seen for muscle and liver. Based on the present results, we propose that sensors such as CS-1 may have a role to play in the clinical and pathological detection of tumour tissues or serve as guiding aids for surgery.A self-assembled amphiphilic fluorescent probe allows pH-fluctuations within cancer cells and tumour tissues to be readily detected. 相似文献
7.
[formula: see text] Exposure of epipodophyllotoxin C4-sulfoxides to triflic anhydride, followed by a silyl glycoside, provides a glycoconjugate of the etoposide variety via formal "reverse Kahne glycosylation." To our knowledge, this is the first example of this variant of the Kahne activation method wherein the activating functionality is positioned on the aglycon, rather than on the sugar. Phenols, anilines, or allyl silanes are also efficiently captured at C4, producing the corresponding O-, N-, and C-linked lignan conjugates. 相似文献
8.
Chemoenzymatic asymmetric synthesis of antidepressant agent venlafaxine and its analogue have been reported in this communication. The main highlight of the reported synthesis is the stereoselective synthesis of cyanohydrins by (S)-hydroxynitrile lyase (Hevea brasiliensis) followed by lipase catalyzed kinetic resolution. 相似文献
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10.
Nihar Ranjan Pani Lila Kanta Nath Sujata Acharya Biswanath Bhuniya 《Journal of Thermal Analysis and Calorimetry》2012,108(1):219-226
Experiments were done to assess the compatibility of nateglinide (NTG) with selected excipients in the development of immediate
release tablets of NTG by thermal and isothermal stress testing (IST) techniques. To evaluate the drug excipient compatibility,
different techniques such as differential scanning calorimetric (DSC) study, infrared (IR) spectrophotometric study, and IST
were adopted. The results of DSC study showed that magnesium stearate exhibited some interaction with NTG. However, the results
of IR and IST studies showed that all the excipients used in the formula were compatible with NTG. The optimized formulation
developed using the compatible excipients were found to be stable after 3 months of accelerated stability studies (40 ± 2 °C
and 75 ± 5% RH). Overall, compatibility of excipients with NTG was successfully evaluated using the combination of thermal
and IST methods and the formulations developed using the compatible excipients was found to be stable. 相似文献