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Bhowmick G, Chakraborty I, Ghangrekar M, Mitra A. TiO2/Activated carbon photo cathode catalyst exposed to ultraviolet radiation to enhance the efficacy of integrated microbial fuel cell-membrane bioreactor. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100303] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Lazarou KA, González-Nieves K, Chakraborty I, Raptis RG. Spontaneous Resolution by Crystallization of an Octanuclear Iron(III) Complex Using Only Racemic Reagents. Angew Chem Int Ed Engl 2019; 58:7324-7328. [PMID: 30891840 DOI: 10.1002/anie.201901877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/17/2019] [Indexed: 11/10/2022]
Abstract
The P and M enantiomers of the octanuclear [Fe8 (μ4 -O)4 (μ-4-Cl-pz)12 Cl4 ] complex, having T symmetry, were resolved by temporary substitution of chloride ligands by racemic 4-s Bu-phenolates and subsequent crystallization, where the (S)- and (R)-phenolates coordinate selectively to the M and P complexes, respectively. The complexes were characterized by circular dichroism analysis and X-ray structure determination. This work constitutes a rare example of enantiomeric recognition resulting in spontaneous resolution upon crystallization.
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Shi K, Mathivathanan L, Boudalis AK, Turek P, Chakraborty I, Raptis RG. Nitrite Reduction by Trinuclear Copper Pyrazolate Complexes: An Example of a Catalytic, Synthetic Polynuclear NO Releasing System. Inorg Chem 2019; 58:7537-7544. [DOI: 10.1021/acs.inorgchem.9b00748] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chakraborty I, Saha U, Mandal D, Mukherjee S, Joardar N, Sinha Babu SP, Suresh Kumar G, Mandal K. Effect of bovine serum albumin on tartrate-modified manganese ferrite nano hollow spheres: spectroscopic and toxicity study. Phys Chem Chem Phys 2019; 21:10726-10737. [PMID: 31086920 DOI: 10.1039/c9cp01877h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The emerging category of magneto-fluorescent tartrate-modified MnFe2O4 nano hollow spheres (T-MnFe2O4 NHSs) can be considered as promising candidates for biomedical applications. The interaction of bovine serum albumin (BSA) with T-MnFe2O4 NHSs has been studied using several spectroscopic techniques, which suggest that the interaction occurs by an electrostatic mechanism. Furthermore, BSA enhances the charge transfer transition from the tartrate ligand to the metal ions along with the d-d transition of Fe3+ ions on NHSs surfaces at different pH. Very strong salt bridge formation occurs between the lysine of the BSA surface and the tartrate in basic medium (pH 10), followed by the acidic (pH 3) and neutral medium (pH 7), respectively. Systematic fluorescence microscopic analysis reveals that BSA significantly enhances the contrast of T-MnFe2O4 NHSs in UV and blue light excitation because of the extended charge transfer from BSA to T-MnFe2O4 NHSs. Our report demonstrates great potential in the field of nanotechnology and biomedical applications. In vitro toxicity analysis using RAW 264.7 celline and in vivo studies on Wister rats revealed that the T-MnFe2O4 NHSs are benign. Furthermore, T-MnFe2O4 NHSs also appear to be an antimicrobial agent. Therefore, T-MnFe2O4 NHSs can be explored for future therapeutic applications.
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Lazarou KA, González‐Nieves K, Chakraborty I, Raptis RG. Spontaneous Resolution by Crystallization of an Octanuclear Iron(III) Complex Using Only Racemic Reagents. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Soe E, Kim JS, Chakraborty I, Oliver SRJ. Synthesis and Characterization of Two Cationic Silver Quinoxaline Coordination Polymers. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Majumder D, Chakraborty I, Mandal K, Roy S. Facet-Dependent Photodegradation of Methylene Blue Using Pristine CeO 2 Nanostructures. ACS OMEGA 2019; 4:4243-4251. [PMID: 31459631 PMCID: PMC6648310 DOI: 10.1021/acsomega.8b03298] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/12/2019] [Indexed: 05/22/2023]
Abstract
This work comprises the shape- and facet-dependent catalytic efficacies of different morphologies of CeO2, namely, hexagonal, rectangular, and square. The formation of different shapes of CeO2 is controlled using polyvinyl pyrrolidone as a surfactant. The surface reactivity of formation of differently exposed CeO2 facets is thoroughly investigated using UV-visible, photoluminescence, Raman, and X-ray photoelectron spectroscopies. A correlation between the growth of a surface-reactive facet and the corresponding oxygen vacancies is also established. Considering the tremendous contamination, caused by the textile effluents, the present study articulates the facet-dependent photocatalytic activities of pristine CeO2 for complete degradation of methylene blue within 175 min. The observed degradation time deploying pristine CeO2 as a catalyst is the shortest to be reported in the literature to our best knowledge.
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Schultz-Simonton W, Skelly P, Chakraborty I, Mascharak P, Braslau R. Synthesis, Structure, and Fluorescence Behavior of Profluorescent 8-Amino BODIPY Nitroxides. European J Org Chem 2019. [DOI: 10.1002/ejoc.201801758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chakraborty S, Chakraborty I. Estimation of Coverage Interval of Serum β-Carotene among Bengali Population. J Clin Diagn Res 2019. [DOI: 10.7860/jcdr/2019/39704.12849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Maitra D, Chatterjee S, Kunti S, Chakraborty I, Majumder B. Assessment of Insulin Resistance in Ultrasonographically Diagnosed Cases of Non-Alcoholic Fatty Liver Disease. J Clin Diagn Res 2019. [DOI: 10.7860/jcdr/2019/42121.13096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Truong PT, Broering EP, Dzul SP, Chakraborty I, Stemmler TL, Harrop TC. Simultaneous nitrosylation and N-nitrosation of a Ni-thiolate model complex of Ni-containing SOD. Chem Sci 2018; 9:8567-8574. [PMID: 30568781 PMCID: PMC6253683 DOI: 10.1039/c8sc03321h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/17/2018] [Indexed: 11/21/2022] Open
Abstract
Nitric oxide (NO) is used as a substrate analogue/spectroscopic probe of metal sites that bind and activate oxygen and its derivatives. To assess the interaction of superoxide with the Ni center in Ni-containing superoxide dismutase (NiSOD), we studied the reaction of NO+ and NO with the model complex, Et4N[Ni(nmp)(SPh-o-NH2-p-CF3)] (1; nmp2- = dianion of N-(2-mercaptoethyl)picolinamide; -SPh-o-NH2-p-CF3 = 2-amino-4-(trifluoromethyl)benzenethiolate) and its oxidized analogue 1ox , respectively. The ultimate products of these reactions are the disulfide of -SPh-o-NH2-p-CF3 and the S,S-bridged tetrameric complex [Ni4(nmp)4], a result of S-based redox activity. However, introduction of NO to 1 affords the green dimeric {NiNO}10 complex (Et4N)2[{Ni(κ2-SPh-o-NNO-p-CF3)(NO)}2] (2) via NO-induced loss of nmp2- as the disulfide and N-nitrosation of the aromatic thiolate. Complex 2 was characterized by X-ray crystallography and several spectroscopies. These measurements are in-line with other tetrahedral complexes in the {NiNO}10 classification. In contrast to the established stability of this metal-nitrosyl class, the Ni-NO bond of 2 is labile and release of NO from this unit was quantified by trapping the NO with a CoII-porphyrin (70-80% yield). In the process, the Ni ends up coordinated by two o-nitrosaminobenzenethiolato ligands to result in the structurally characterized trans-(Et4N)2[Ni(SPh-o-NNO-p-CF3)2] (3), likely by a disproportionation mechanism. The isolation and characterization of 2 and 3 suggest that: (i) the strongly donating thiolates dominate the electronic structure of Ni-nitrosyls that result in less covalent Ni-NO bonds, and (ii) superoxide undergoes disproportionation via an outer-sphere mechanism in NiSOD as complexes in the {NiNO}9/8 state have yet to be isolated.
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Kandel S, Stenger-Smith J, Chakraborty I, Raptis RG. Syntheses and X-ray crystal structures of a family of dinuclear silver(I)pyrazolates: Assessment of their antibacterial efficacy against P. aeruginosa with a soft tissue and skin infection model. Polyhedron 2018. [DOI: 10.1016/j.poly.2018.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Chakraborty I, Roy D, Roy K. Technology Aware Training in Memristive Neuromorphic Systems for Nonideal Synaptic Crossbars. IEEE TRANSACTIONS ON EMERGING TOPICS IN COMPUTATIONAL INTELLIGENCE 2018. [DOI: 10.1109/tetci.2018.2829919] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Chakraborty I, Saha G, Sengupta A, Roy K. Toward Fast Neural Computing using All-Photonic Phase Change Spiking Neurons. Sci Rep 2018; 8:12980. [PMID: 30154507 PMCID: PMC6113276 DOI: 10.1038/s41598-018-31365-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 08/17/2018] [Indexed: 11/24/2022] Open
Abstract
The rapid growth of brain-inspired computing coupled with the inefficiencies in the CMOS implementations of neuromrphic systems has led to intense exploration of efficient hardware implementations of the functional units of the brain, namely, neurons and synapses. However, efforts have largely been invested in implementations in the electrical domain with potential limitations of switching speed, packing density of large integrated systems and interconnect losses. As an alternative, neuromorphic engineering in the photonic domain has recently gained attention. In this work, we propose a purely photonic operation of an Integrate-and-Fire Spiking neuron, based on the phase change dynamics of Ge2Sb2Te5 (GST) embedded on top of a microring resonator, which alleviates the energy constraints of PCMs in electrical domain. We also show that such a neuron can be potentially integrated with on-chip synapses into an all-Photonic Spiking Neural network inferencing framework which promises to be ultrafast and can potentially offer a large operating bandwidth.
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Chakraborty I, Kandel S, Raptis RG. Structural diversity of mercury(II) complexes derived from substituted pyrazoles. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318098616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Pinto MN, Martinez-Gonzalez J, Chakraborty I, Mascharak PK. Incorporation of a Theranostic “Two-Tone” Luminescent Silver Complex into Biocompatible Agar Hydrogel Composite for the Eradication of ESKAPE Pathogens in a Skin and Soft Tissue Infection Model. Inorg Chem 2018; 57:6692-6701. [DOI: 10.1021/acs.inorgchem.8b00901] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Stenger-Smith J, Chakraborty I, Mascharak PK. Cationic Au(I) complexes with aryl-benzothiazoles and their antibacterial activity. J Inorg Biochem 2018; 185:80-85. [PMID: 29800748 DOI: 10.1016/j.jinorgbio.2018.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/04/2018] [Accepted: 05/08/2018] [Indexed: 11/16/2022]
Abstract
Two cationic Au(I) complexes derived from aryl-benzothiazoles, namely [(PPh3)Au(pbt)](OTf) (1) and [(PPh3)Au(qbt)](OTf) (2) (where pbt = 2‑(pyridyl)benzothiazole and qbt = (quinolyl)benzothiazole, and OTf- = trifluoromethanesulfonate anion), have been synthesized and structurally characterized by X-ray crystallography. Both complexes exhibit strong antibacterial effects against Gram-negative bacteria such as Acinetobacter baumannii and Pseudomonas Aeruginosa. Results of examination of the reactions of 1 and 2 indicate that these cationic Au(I) complexes rapidly cross the bacterial membrane and exert drug action by disrupting cellular function(s) through binding of cytosolic thiol-containing peptides (such as glutathione) and proteins to the highly reactive (PPh3)Au+ intermediate formed upon in situ dissociation of pbt or qbt.
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Chakraborty I, Jimenez J, Mascharak PK. CO-Induced apoptotic death of colorectal cancer cells by a luminescent photoCORM grafted on biocompatible carboxymethyl chitosan. Chem Commun (Camb) 2018; 53:5519-5522. [PMID: 28466932 DOI: 10.1039/c7cc02842c] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A photo-active luminescent rhenium carbonyl complex namely, [Re(CO)3(phen)(pyAl)](CF3SO3) was grafted on a biocompatible carboxymethyl chitosan (CMC) matrix through Schiff base condensation reaction. The light-induced CO delivery from ReCMC has been shown to eradicate human colorectal adenocarcinoma cells (HT-29) very efficiently in a dose-dependent fashion. The onset of CO-induced apoptosis was realized by caspase-3,-7 detection aided by fluorescence confocal microscopy. ReCMC represents a unique example of a biocompatible and biodegradable antineoplastic agent that could find its use in cancer photopharmacology.
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Jimenez J, Chakraborty I, Dominguez A, Martinez-Gonzalez J, Sameera WMC, Mascharak PK. A Luminescent Manganese PhotoCORM for CO Delivery to Cellular Targets under the Control of Visible Light. Inorg Chem 2018; 57:1766-1773. [DOI: 10.1021/acs.inorgchem.7b02480] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Stenger-Smith J, Chakraborty I, Sameera W, Mascharak PK. Antimicrobial silver (I) complexes derived from aryl-benzothiazoles as turn-on sensors: Syntheses, properties and density functional studies. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.11.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Colinas IR, Rojas-Andrade MD, Chakraborty I, Oliver SRJ. Two structurally diverse Zn-based coordination polymers with excellent antibacterial activity. CrystEngComm 2018. [DOI: 10.1039/c8ce00394g] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Two novel Zn-based coordination polymers with unique structural properties display an exceptional antibacterial activity against Gram-positive and Gram-negative bacteria.
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Pinto M, Chakraborty I, Martinez-Gonzalez J, Mascharak P. Synthesis and structures of photoactive rhenium carbonyl complexes derived from 2-(pyridin-2-yl)-1,3-benzothiazole, 2-(quinolin-2-yl)-1,3-benzothiazole and 1,10-phenanthroline. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2017; 73:923-929. [PMID: 29111520 DOI: 10.1107/s2053229617014644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/10/2017] [Indexed: 11/10/2022]
Abstract
Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site-specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group-7-based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence. The inherent luminecscent nature of some photoCORMs and the change in emission wavelength upon CO release also provide a covenient means to track the entry of the prodrug and, in some cases, both the entry and CO release from the prodrug. In continuation of the research circumscribing the development of trackable photoCORMs and also to graft such molecules covalently to conventional delivery vehicles, we report herein the synthesis and structures of three rhenium carbonyl complexes, namely, fac-tricarbonyl[2-(pyridin-2-yl)-1,3-benzothiazole-κ2N,N'](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2S)(CO)3](CF3SO3), (1), fac-tricarbonyl[2-(quinolin-2-yl)-1,3-benzothiazole-κ2N,N'](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C16H10N2S)(CO)3](CF3SO3), (2), and fac-tricarbonyl[1,10-phenanthroline-κ2N,N'](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2)(CO)3](CF3SO3), (3). In all three complexes, the ReI center resides in a distorted octahedral coordination environment. These complexes exhibit CO release upon exposure to low-power UV light. The apparent CO release rates of the complexes have been measured to assess their comparative CO-donating capacity. The three complexes are highly luminescent and this in turn provides a convenient way to track the entry of the prodrug molecules within biological targets.
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Chakraborty I, Ricouvier J, Yazhgur P, Tabeling P, Leshansky AM. Microfluidic step-emulsification in axisymmetric geometry. LAB ON A CHIP 2017; 17:3609-3620. [PMID: 28944810 DOI: 10.1039/c7lc00755h] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Biphasic step-emulsification (Z. Li et al., Lab Chip, 2015, 15, 1023) is a promising microfluidic technique for high-throughput production of μm and sub-μm highly monodisperse droplets. The step-emulsifier consists of a shallow (Hele-Shaw) microchannel operating with two co-flowing immiscible liquids and an abrupt expansion (i.e., step) to a deep and wide reservoir. Under certain conditions the confined stream of the disperse phase, engulfed by the co-flowing continuous phase, breaks into small highly monodisperse droplets at the step. Theoretical investigation of the corresponding hydrodynamics is complicated due to the complex geometry of the planar device, calling for numerical approaches. However, direct numerical simulations of the three dimensional surface-tension-dominated biphasic flows in confined geometries are computationally expensive. In the present paper we study a model problem of axisymmetric step-emulsification. This setup consists of a stable core-annular biphasic flow in a cylindrical capillary tube connected co-axially to a reservoir tube of a larger diameter through a sudden expansion mimicking the edge of the planar step-emulsifier. We demonstrate that the axisymmetric setup exhibits similar regimes of droplet generation to the planar device. A detailed parametric study of the underlying hydrodynamics is feasible via inexpensive (two dimensional) simulations owing to the axial symmetry. The phase diagram quantifying the different regimes of droplet generation in terms of governing dimensionless parameters is presented. We show that in qualitative agreement with experiments in planar devices, the size of the droplets generated in the step-emulsification regime is independent of the capillary number and almost insensitive to the viscosity ratio. These findings confirm that the step-emulsification regime is solely controlled by surface tension. The numerical predictions are in excellent agreement with in-house experiments with the axisymmetric step-emulsifier.
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Chakraborty I, Tena J, Mascharak PK. Photoactive rhenium carbonyl complexes of N,N,S-donor ligands: Contrast in binding modes based on flexibility of ligand frames and nature of ancillary ligands. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.08.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pinto MN, Chakraborty I, Sandoval C, Mascharak PK. Eradication of HT-29 colorectal adenocarcinoma cells by controlled photorelease of CO from a CO-releasing polymer (photoCORP-1) triggered by visible light through an optical fiber-based device. J Control Release 2017; 264:192-202. [PMID: 28866022 DOI: 10.1016/j.jconrel.2017.08.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/06/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
Abstract
The gaseous signaling molecule carbon monoxide (CO) has recently been recognized for its wide range of physiological activity as well as its antineoplastic properties. However, site-specific delivery of this noxious gas presents a major challenge in hospital settings. In this work, a visible light-sensitive CO-releasing molecule (photoCORM) derived from manganese(I) and 2-(quinolyl)benzothiazole (qbt) namely, [Mn(CO)3(qbt)(4-vpy)](CF3SO3) (1), has been co-polymerized within a gas-permeable HEMA/EGDMA hydrogel. The resulting photoactive CO-releasing polymer (photoCORP-1) incorporates 1 such that neither the carbonyl complex nor its photoproduct(s) exits the polymer at any time. The material can be triggered to photorelease CO remotely by low-power broadband visible light (<1mWcm-2) with the aid of fiber optics technology. The CO photorelease rates of photoCORP-1 (determined by spectrophotometry) can be modulated by both the concentration of 1 in the hydrogel and the intensity of the light. A CO-delivery device has been assembled to deliver CO to a suspension of human colorectal adenocarcinoma cells (HT-29) under the control of visible light and the extent of CO-induced apoptotic death of the cancer cells has been determined via Annexin V/Propidium iodide stain and flow cytometry. This photoactive CO-releasing polymer could find use in delivering controlled doses of CO to cellular targets such as malignant tissues in remote parts of the body.
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