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Karandish F, Mamnoon B, Feng L, Haldar MK, Xia L, Gange KN, You S, Choi Y, Sarkar K, Mallik S. Nucleus-Targeted, Echogenic Polymersomes for Delivering a Cancer Stemness Inhibitor to Pancreatic Cancer Cells. Biomacromolecules 2018; 19:4122-4132. [PMID: 30169024 DOI: 10.1021/acs.biomac.8b01133] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chemotherapeutic agents for treating cancers show considerable side effects, toxicity, and drug resistance. To mitigate the problems, we designed nucleus-targeted, echogenic, stimuli-responsive polymeric vesicles (polymersomes) to transport and subsequently release the encapsulated anticancer drugs within the nuclei of pancreatic cancer cells. We synthesized an alkyne-dexamethasone derivative and conjugated it to N3-polyethylene glycol (PEG)-polylactic acid (PLA) copolymer employing the Cu2+ catalyzed "Click" reaction. We prepared polymersomes from the dexamethasone-PEG-PLA conjugate along with a synthesized stimuli-responsive polymer PEG-S-S-PLA. The dexamethasone group dilates the nuclear pore complexes and transports the vesicles to the nuclei. We designed the polymersomes to release the encapsulated drugs in the presence of a high concentration of reducing agents in the nuclei of pancreatic cancer cells. We observed that the nucleus-targeted, stimuli-responsive polymersomes released 70% of encapsulated contents in the nucleus-mimicking environment in 80 min. We encapsulated the cancer stemness inhibitor BBI608 in the vesicles and observed that the BBI608 encapsulated polymersomes reduced the viability of the BxPC3 cells to 43% in three-dimensional spheroid cultures. The polymersomes were prepared following a special protocol so that they scatter ultrasound, allowing imaging by a medical ultrasound scanner. Therefore, these echogenic, targeted, stimuli-responsive, and drug-encapsulated polymersomes have the potential for trackable, targeted carrier of chemotherapeutic drugs to cancer cell nuclei.
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Miao S, Cui H, Nowicki M, Xia L, Zhou X, Lee SJ, Zhu W, Sarkar K, Zhang Z, Zhang LG. Stereolithographic 4D Bioprinting of Multiresponsive Architectures for Neural Engineering. ADVANCED BIOSYSTEMS 2018; 2:1800101. [PMID: 30906853 PMCID: PMC6430203 DOI: 10.1002/adbi.201800101] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 01/12/2023]
Abstract
4D printing represents one of the most advanced fabrication techniques for prospective applications in tissue engineering, biomedical devices, and soft robotics, among others. In this study, a novel multiresponsive architecture is developed through stereolithography-based 4D printing, where a universal concept of stress-induced shape transformation is applied to achieve the 4D reprogramming. The light-induced graded internal stress followed by a subsequent solvent-induced relaxation, driving an autonomous and reversible change of the programmed configuration after printing, is employed and investigated in depth and details. Moreover, the fabricated construct possesses shape memory property, offering a characteristic of multiple shape change. Using this novel multiple responsive 4D technique, a proof-of-concept smart nerve guidance conduit is demonstrated on a graphene hybrid 4D construct providing outstanding multifunctional characteristics for nerve regeneration including physical guidance, chemical cues, dynamic self-entubulation, and seamless integration. By employing this fabrication technique, creating multiresponsive smart architectures, as well as demonstrating application potential, this work paves the way for truly initiation of 4D printing in various high-value research fields.
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Aliabouzar M, Zhang GL, Sarkar K. Acoustic and mechanical characterization of 3D-printed scaffolds for tissue engineering applications. Biomed Mater 2018; 13:055013. [DOI: 10.1088/1748-605x/aad417] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kulkarni P, Haldar MK, Karandish F, Confeld M, Hossain R, Borowicz P, Gange K, Xia L, Sarkar K, Mallik S. Tissue-Penetrating, Hypoxia-Responsive Echogenic Polymersomes For Drug Delivery To Solid Tumors. Chemistry 2018; 24:12490-12494. [PMID: 29968262 DOI: 10.1002/chem.201802229] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/22/2018] [Indexed: 01/02/2023]
Abstract
Hypoxia in solid tumors facilitates the progression of the disease, develops resistance to chemo and radiotherapy, and contributes to relapse. Due to the lack of tumor penetration, most of the reported drug carriers are unable to reach the hypoxic niches of the solid tumors. We have developed tissue-penetrating, hypoxia-responsive echogenic polymersomes to deliver anticancer drugs to solid tumors. The polymersomes are composed of a hypoxia-responsive azobenzene conjugated and a tissue penetrating peptide functionalized polylactic acid-polyethylene glycol polymer. The drug-encapsulated, hypoxia-responsive polymersomes substantially decreased the viability of pancreatic cancer cells in spheroidal cultures. Under normoxic conditions, polymersomes were echogenic at diagnostic ultrasound frequencies but lose the echogenicity under hypoxia. In-vivo imaging studies with xenograft mouse model further confirmed the ability of the polymersomes to target, penetrate, and deliver the encapsulated contents in hypoxic pancreatic tumor tissues.
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Aliabouzar M, Kumar KN, Sarkar K. Acoustic vaporization threshold of lipid-coated perfluoropentane droplets. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 143:2001. [PMID: 29716255 PMCID: PMC5895468 DOI: 10.1121/1.5027817] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Phase shift droplets vaporizable by acoustic stimulation offer the advantages of producing microbubbles as contrast agents in situ as well as higher stability and the possibility of achieving smaller sizes. Here, the acoustic droplet vaporization (ADV) threshold of a suspension of droplets with a perfluoropentane (PFP) core (diameter 400-3000 nm) is acoustically measured as a function of the excitation frequency in a tubeless setup at room temperature. The changes in scattered responses-fundamental, sub-, and second harmonic-are investigated, a quantitative criterion is used to determine the ADV phenomenon, and findings are discussed. The average threshold obtained using three different scattered components increases with frequency-1.05 ± 0.28 MPa at 2.25 MHz, 1.89 ± 0.57 MPa at 5 MHz, and 2.34 ± 0.014 MPa at 10 MHz. The scattered response from vaporized droplets was also found to qualitatively match with that from an independently prepared lipid-coated microbubble suspension in magnitude as well as trends above the determined ADV threshold value.
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Xia L, Karandish F, Kumar KN, Froberg J, Kulkarni P, Gange KN, Choi Y, Mallik S, Sarkar K. Acoustic Characterization of Echogenic Polymersomes Prepared From Amphiphilic Block Copolymers. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:447-457. [PMID: 29229268 DOI: 10.1016/j.ultrasmedbio.2017.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 10/06/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
Polymersomes are a class of artificial vesicles prepared from amphiphilic polymers. Like lipid vesicles (liposomes), they too can encapsulate hydrophilic and hydrophobic drug molecules in the aqueous core and the hydrophobic bilayer respectively, but are more stable than liposomes. Although echogenic liposomes have been widely investigated for simultaneous ultrasound imaging and controlled drug delivery, the potential of the polymersomes remains unexplored. We prepared two different echogenic polymersomes from the amphiphilic copolymers polyethylene glycol-poly-DL-lactic acid (PEG-PLA) and polyethylene glycol-poly-L-lactic acid (PEG-PLLA), incorporating multiple freeze-dry cycles in the synthesis protocol to ensure their echogenicity. We investigated acoustic behavior with potential applications in biomedical imaging. We characterized the polymeric vesicles acoustically with three different excitation frequencies of 2.25, 5 and 10 MHz at 500 kPa. The polymersomes exhibited strong echogenicity at all three excitation frequencies (about 50- and 25-dB enhancements in fundamental and subharmonic, respectively, at 5-MHz excitation from 20 µg/mL polymers in solution). Unlike echogenic liposomes, they emitted strong subharmonic responses. The scattering results indicated their potential as contrast agents, which was also confirmed by clinical ultrasound imaging.
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Miao S, Castro N, Nowicki M, Xia L, Cui H, Zhou X, Zhu W, Lee SJ, Sarkar K, Vozzi G, Tabata Y, Fisher J, Zhang LG. 4D printing of polymeric materials for tissue and organ regeneration. MATERIALS TODAY (KIDLINGTON, ENGLAND) 2017; 20:577-591. [PMID: 29403328 PMCID: PMC5796676 DOI: 10.1016/j.mattod.2017.06.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Four dimensional (4D) printing is an emerging technology with great capacity for fabricating complex, stimuli-responsive 3D structures, providing great potential for tissue and organ engineering applications. Although the 4D concept was first highlighted in 2013, extensive research has rapidly developed, along with more-in-depth understanding and assertions regarding the definition of 4D. In this review, we begin by establishing the criteria of 4D printing, followed by an extensive summary of state-of-the-art technological advances in the field. Both transformation-preprogrammed 4D printing and 4D printing of shape memory polymers are intensively surveyed. Afterwards we will explore and discuss the applications of 4D printing in tissue and organ regeneration, such as developing synthetic tissues and implantable scaffolds, as well as future perspectives and conclusions.
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Kumar KN, Mallik S, Sarkar K. Role of freeze-drying in the presence of mannitol on the echogenicity of echogenic liposomes. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:3670. [PMID: 29289081 PMCID: PMC5736393 DOI: 10.1121/1.5017607] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 11/15/2017] [Accepted: 11/23/2017] [Indexed: 05/18/2023]
Abstract
Echogenic liposomes (ELIPs) are an excellent candidate for ultrasound activated therapeutics and imaging. Although multiple experiments have established their echogenicity, the underlying mechanism has remained unknown. However, freeze-drying in the presence of mannitol during ELIP preparation has proved critical to ensuring echogenicity. Here, the role of this key component in the preparation protocol was investigated by measuring scattering from freshly prepared freeze-dried aqueous solution of mannitol-and a number of other excipients commonly used in lyophilization-directly dispersed in water without any lipids in the experiment. Mannitol, meso-erythritol, glycine, and glucose that form a highly porous crystalline phase upon freeze-drying generated bubbles resulting in strong echoes during their dissolution. On the other hand, sucrose, trehalose, and xylitol, which become glassy while freeze-dried, did not. Freeze-dried mannitol and other crystalline substances, if thawed before being introduced into the scattering volume, did not produce echogenicity, as they lost their crystallinity in the thawed state. The echogenicity disappeared in a degassed environment. Higher amounts of sugar in the original aqueous solution before freeze-drying resulted in higher echogenicity because of the stronger supersaturation and crystallinity. The bubbles created by the freeze-dried mannitol in the ELIP formulation play a critical role in making ELIPs echogenic.
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Aliabouzar M, Lee SJ, Zhou X, Zhang GL, Sarkar K. Effects of scaffold microstructure and low intensity pulsed ultrasound on chondrogenic differentiation of human mesenchymal stem cells. Biotechnol Bioeng 2017; 115:495-506. [DOI: 10.1002/bit.26480] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/24/2017] [Accepted: 08/15/2017] [Indexed: 01/07/2023]
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Sarkar K, Palit M, Guhathakurata S, Chattopadhyay S, Banerji P. Single In x Ga 1-x As nanowire/p-Si heterojunction based nano-rectifier diode. NANOTECHNOLOGY 2017; 28:385202. [PMID: 28696342 DOI: 10.1088/1361-6528/aa7f19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanoscale power supply units will be indispensable for fabricating next generation smart nanoelectronic integrated circuits. Fabrication of nanoscale rectifier circuits on a Si platform is required for integrating nanoelectronic devices with on-chip power supply units. In the present study, a nanorectifier diode based on a single standalone In x Ga1-x As nanowire/p-Si (111) heterojunction fabricated by metal organic chemical vapor deposition technique has been studied. The nanoheterojunction diodes have shown good rectification and fast switching characteristics. The rectification characteristics of the nanoheterojunction have been demonstrated by different standard waveforms of sinusoidal, square, sawtooth and triangular for two different frequencies of 1 and 0.1 Hz. Reverse recovery time of around 150 ms has been observed in all wave response. A half wave rectifier circuit with a simple capacitor filter has been assembled with this nanoheterojunction diode which provides 12% output efficiency. The transport of carriers through the heterojunction is investigated. The interface states density of the nanoheterojunction has also been determined. Occurrence of output waveforms incommensurate with the input is attributed to higher series resistance of the diode which is further explained considering the dimension of p-side and n-side of the junction. The sudden change of ideality factor after 1.7 V bias is attributed to recombination through interface states in space charge region. Low interface states density as well as high rectification ratio makes this heterojunction diode a promising candidate for future nanoscale electronics.
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Sarkar K, Mallick I, Mallath M, Dabkara D, Biswas B, Banerjee S, Ray M, Chatterjee S, Shrimali R. Role of High Dose Radiotherapy for Locally Advanced Pancreatic Cancer – a Single Centre Experience from Eastern India. Clin Oncol (R Coll Radiol) 2017. [DOI: 10.1016/j.clon.2016.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Aliabouzar M, Zhang LG, Sarkar K. Lipid Coated Microbubbles and Low Intensity Pulsed Ultrasound Enhance Chondrogenesis of Human Mesenchymal Stem Cells in 3D Printed Scaffolds. Sci Rep 2016; 6:37728. [PMID: 27883051 PMCID: PMC5121887 DOI: 10.1038/srep37728] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 10/31/2016] [Indexed: 12/12/2022] Open
Abstract
Lipid-coated microbubbles are used to enhance ultrasound imaging and drug delivery. Here we apply these microbubbles along with low intensity pulsed ultrasound (LIPUS) for the first time to enhance proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in a 3D printed poly-(ethylene glycol)-diacrylate (PEG-DA) hydrogel scaffold. The hMSC proliferation increased up to 40% after 5 days of culture in the presence of 0.5% (v/v) microbubbles and LIPUS in contrast to 18% with LIPUS alone. We systematically varied the acoustic excitation parameters-excitation intensity, frequency and duty cycle-to find 30 mW/cm2, 1.5 MHz and 20% duty cycle to be optimal for hMSC proliferation. A 3-week chondrogenic differentiation results demonstrated that combining LIPUS with microbubbles enhanced glycosaminoglycan (GAG) production by 17% (5% with LIPUS alone), and type II collagen production by 78% (44% by LIPUS alone). Therefore, integrating LIPUS and microbubbles appears to be a promising strategy for enhanced hMSC growth and chondrogenic differentiation, which are critical components for cartilage regeneration. The results offer possibilities of novel applications of microbubbles, already clinically approved for contrast enhanced ultrasound imaging, in tissue engineering.
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Zhou X, Castro NJ, Zhu W, Cui H, Aliabouzar M, Sarkar K, Zhang LG. Improved Human Bone Marrow Mesenchymal Stem Cell Osteogenesis in 3D Bioprinted Tissue Scaffolds with Low Intensity Pulsed Ultrasound Stimulation. Sci Rep 2016; 6:32876. [PMID: 27597635 PMCID: PMC5011779 DOI: 10.1038/srep32876] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 08/16/2016] [Indexed: 12/14/2022] Open
Abstract
3D printing and ultrasound techniques are showing great promise in the evolution of human musculoskeletal tissue repair and regeneration medicine. The uniqueness of the present study was to combine low intensity pulsed ultrasound (LIPUS) and advanced 3D printing techniques to synergistically improve growth and osteogenic differentiation of human mesenchymal stem cells (MSC). Specifically, polyethylene glycol diacrylate bioinks containing cell adhesive Arginine-Glycine-Aspartic acid-Serene (RGDS) peptide and/or nanocrystalline hydroxyapatite (nHA) were used to fabricate 3D scaffolds with different geometric patterns via novel table-top stereolithography 3D printer. The resultant scaffolds provide a highly porous and interconnected 3D environment to support cell proliferation. Scaffolds with small square pores were determined to be the optimal geometric pattern for MSC attachment and growth. The optimal LIPUS working parameters were determined to be 1.5 MHz, 20% duty cycle with 150 mW/cm(2) intensity. Results demonstrated that RGDS peptide and nHA containing 3D printed scaffolds under LIPUS treatment can greatly promote MSC proliferation, alkaline phosphatase activity, calcium deposition and total protein content. These results illustrate the effectiveness of the combination of LIPUS and biomimetic 3D printing scaffolds as a valuable combinatorial tool for improved MSC function, thus make them promising for future clinical and various regenerative medicine application.
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Kumar KN, Sarkar K. Interfacial Rheological Properties of Contrast Microbubble Targestar P as a Function of Ambient Pressure. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1010-1017. [PMID: 26777069 DOI: 10.1016/j.ultrasmedbio.2015.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/04/2015] [Accepted: 11/18/2015] [Indexed: 06/05/2023]
Abstract
In this Technical Note, we determine the interfacial rheological parameters of the encapsulation of the contrast agent Targestar P using ultrasound attenuation. The characteristic parameters are obtained according to two interfacial rheological models. The properties-surface dilatational elasticity (0.09 ± 0.01 N/m) and surface dilatational viscosity (8 ± 0.1E-9 N·s/m)-are found to be of similar magnitude for both models. Contrast microbubbles experience different ambient pressure in different organs. We also measure these parameters as functions of ambient pressure using attenuation measured at different overpressures (0, 100 and 200 mm Hg). For each value of ambient hydrostatic pressure, we determine the rheological properties, accounting for changes in the size distribution caused by the pressure change. We discuss different models of size distribution change under overpressure: pure adiabatic compression or gas exchange with surrounding medium. The dilatational surface elasticity and viscosity are found to increase with increasing ambient pressure.
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Mallick I, Bhaumik S, Sarkar K, Arun P, Manikantan K, Roy P, Arun I, Dabkara D, Chatterjee S. EP-1042: Risk-factors in pT1-2N0M0 squamous cancers of the oral cavity and the role of adjuvant radiotherapy. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)32292-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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41
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Singh RK, Sarkar K. Hydrodynamic interactions between pairs of capsules and drops in a simple shear: Effects of viscosity ratio and heterogeneous collision. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:063029. [PMID: 26764825 DOI: 10.1103/physreve.92.063029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Indexed: 06/05/2023]
Abstract
Hydrodynamic interactions between a pair of capsules in simple shear are numerically investigated using a front-tracking finite difference method. The membrane of the capsule is modeled using different hyperelastic constitutive relations. We also compare the pair interactions between drops to those between capsules. An increased viscosity ratio leads to a reduced net cross-stream separation between capsules as well as drops after collision. At low viscosity ratios, for the same capillary number drop-pairs show higher cross-stream separation than those for capsule-pairs, while substantially large viscosity ratios result in almost the same value for both cases. We investigate pair-collisions between two heterogeneous capsules C(1) and C(2) with two different capillary numbers. The maximum deformation of C(1) was seen to increase with increasing stiffness (decreasing capillary number) of C(2), even though the stiffness of C(1) was kept fixed. The findings are similar for a drop-pair, however, with a smaller maximum deformation for the same combinations of capillary numbers. The final cross-stream drift of the trajectory of C(1) decreases with the increasing stiffness of C(2), but the relative trajectory between the capsules remains unchanged. The maximum deformation and the cross-stream drift of the trajectory of C(1) are shown to approximately vary with power-law functions of the ratio of the capillary numbers of C(1) and C(2). An analytical explanation of the dependence on the two capillary numbers is offered. Different membrane constitutive laws result in similar deformation and drift in trajectory.
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Xia L, Porter TM, Sarkar K. Interpreting attenuation at different excitation amplitudes to estimate strain-dependent interfacial rheological properties of lipid-coated monodisperse microbubbles. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:3994-4003. [PMID: 26723353 DOI: 10.1121/1.4938234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Broadband attenuation of ultrasound measured at different excitation pressures being different raises a serious theoretical concern, because the underlying assumption of linear and independent propagation of different frequency components nominally requires attenuation to be independent of excitation. Here, this issue is investigated by examining ultrasound attenuation through a monodisperse lipid-coated microbubble suspension measured at four different acoustic excitation amplitudes. The attenuation data are used to determine interfacial rheological properties (surface tension, surface dilatational elasticity, and surface dilatational viscosity) of the encapsulation according to three different models. Although different models result in similar rheological properties, attenuation measured at different excitation levels (4-110 kPa) leads to different values for them; the dilatation elasticity (0.56 to 0.18 N/m) and viscosity (2.4 × 10(-8) to 1.52 × 10(-8) Ns/m) both decrease with increasing pressure. Numerically simulating the scattered response, nonlinear energy transfer between frequencies are shown to be negligible, thereby demonstrating the linearity in propagation and validating the attenuation analysis. There is a second concern to the characterization arising from shell properties being dependent on excitation amplitude, which is not a proper constitutive variable. It is resolved by arriving at a strain-dependent rheology for the encapsulation. The limitations of the underlying analysis are discussed.
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Kumar KN, Sarkar K. Effects of ambient hydrostatic pressure on the material properties of the encapsulation of an ultrasound contrast microbubble. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:624-634. [PMID: 26328681 DOI: 10.1121/1.4923364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ultrasound contrast microbubbles experience widely varying ambient blood pressure in different organs, which can also change due to diseases. Pressure change can alter the material properties of the encapsulation of these microbubbles. Here the characteristic rheological parameters of contrast agent Definity are determined by varying the ambient pressure (in a physiologically relevant range 0-200 mm Hg). Four different interfacial rheological models are used to characterize the microbubbles. Effects of gas diffusion under excess ambient pressure are investigated in detail accounting for size decrease of contrast microbubbles. Definity contrast agent show a change in their interfacial dilatational viscosity (3.6 × 10(-8) Ns/m at 0 mm Hg to 4.45 × 10(-8) Ns/m at 200 mm Hg) and interfacial dilatational elasticity (0.86 N/m at 0 mm Hg to 1.06 N/m at 200 mm Hg) with ambient pressure increase. The increase results from material consolidation, similar to such enhancement in bulk properties under pressure. The model that accounts for enhancement in material properties with increasing ambient pressure matches with experimentally measured subharmonic response as a function of ambient pressure, while assuming constant material parameters does not.
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Pilaka V, Sarkar K, Ahmed R, Mahata A, Mallick I, Shrimali R, Achari R, Chatterjee S. PO-0788: Do heart and lung distances correlate to DVH when irradiating with forward planned IMRT techniques in breast cancer? Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40780-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Chatterjee S, Reddy V, Sarkar K, Ahmed R, Mahata A, Mallick I, Shrimali R, Achari R. PO-0690: Answering questions for hypofractionated RT in Indian breast cancers: analysis of toxicities and outcomes. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40682-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Mukherjee S, Sarkar K, Mukherjee S. Effect of Nickel and Cobalt Doping on Nano Bismuth Ferrite Prepared by the Chemical Route. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/bf03401099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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47
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Sarkar K, Palit M, Banerji P, Chattopadhyay S, Halder NN, Biswas P, Nagabhusan B, Chowdhury S. Silver catalyzed growth of InxGa1−xAs nanowires on Si(001) by metal–organic chemical vapor deposition. CrystEngComm 2015. [DOI: 10.1039/c5ce01565k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Sarkar K, Sarkar KJ, Banerji P. Synthesis of graphene oxide–silver nanocomposite with photochemically grown silver nanoparticles to use as a channel material in thin film field effect transistors. RSC Adv 2015. [DOI: 10.1039/c5ra23069a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The transport of charge carriers in a graphene oxide–silver nanoparticle composite is found to be controlled by nanoparticle dose.
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Islam SM, Sarkar K, Banerji P, Sarkar KJ, Pal B. Leakage current characteristics in MOCVD grown InAs quantum dot embedded GaAs metal-oxide-semiconductor capacitor. RSC Adv 2015. [DOI: 10.1039/c5ra15642d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Carrier transport vis-a-vis leakage current in GaAs MOS capacitors with various structures; quantum dot embedded devices show the lowest leakage.
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Nahire R, Hossain R, Patel R, Paul S, Meghnani V, Ambre AH, Gange KN, Katti KS, Leclerc E, Srivastava DK, Sarkar K, Mallik S. pH-triggered echogenicity and contents release from liposomes. Mol Pharm 2014; 11:4059-68. [PMID: 25271780 PMCID: PMC4224524 DOI: 10.1021/mp500186a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Liposomes are representative lipid
nanoparticles widely used for
delivering anticancer drugs, DNA fragments, or siRNA to cancer cells.
Upon targeting, various internal and external triggers have been used
to increase the rate for contents release from the liposomes. Among
the internal triggers, decreased pH within the cellular lysosomes
has been successfully used to enhance the rate for releasing contents.
However, imparting pH sensitivity to liposomes requires the synthesis
of specialized lipids with structures that are substantially modified
at a reduced pH. Herein, we report an alternative strategy to render
liposomes pH sensitive by encapsulating a precursor which generates
gas bubbles in situ in response to acidic pH. The
disturbance created by the escaping gas bubbles leads to the rapid
release of the encapsulated contents from the liposomes. Atomic force
microscopic studies indicate that the liposomal structure is destroyed
at a reduced pH. The gas bubbles also render the liposomes echogenic,
allowing ultrasound imaging. To demonstrate the applicability of this
strategy, we have successfully targeted doxorubicin-encapsulated liposomes
to the pancreatic ductal carcinoma cells that overexpress the folate
receptor on the surface. In response to the decreased pH in the lysosomes,
the encapsulated anticancer drug is efficiently released. Contents
released from these liposomes are further enhanced by the application
of continuous wave ultrasound (1 MHz), resulting in substantially
reduced viability for the pancreatic cancer cells (14%).
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