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Stankiewicz A. Sampling Points-Independent Identification of the Fractional Maxwell Model of Viscoelastic Materials Based on Stress Relaxation Experiment Data. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1527. [PMID: 38612043 PMCID: PMC11012696 DOI: 10.3390/ma17071527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 03/21/2024] [Accepted: 03/24/2024] [Indexed: 04/14/2024]
Abstract
Considerable development has been observed in the area of applying fractional-order rheological models to describe the viscoelastic properties of miscellaneous materials in the last few decades together with the increasingly stronger adoption of fractional calculus. The fractional Maxwell model is the best-known non-integer-order rheological model. A weighted least-square approximation problem of the relaxation modulus by the fractional Maxwell model is considered when only the time measurements of the relaxation modulus corrupted by additive noises are accessible for identification. This study was dedicated to the determination of the model, optimal in the sense of the integral square weighted model quality index, which does not depend on the particular sampling points applied in the stress relaxation experiment. It is proved that even when the real description of the material relaxation modulus is entirely unknown, the optimal fractional Maxwell model parameters can be recovered from the relaxation modulus measurements recorded for sampling time points selected randomly according to respective randomization. The identified model is a strongly consistent estimate of the desired optimal model. The exponential convergence rate is demonstrated both by the stochastic convergence analysis and by the numerical studies. A simple scheme for the optimal model identification is given. Numerical studies are presented for the materials described by the short relaxation times of the unimodal Gauss-like relaxation spectrum and the long relaxation times of the Baumgaertel, Schausberger and Winter spectrum. These studies have shown that the appropriate randomization introduced in the selection of sampling points guarantees that the sequence of the optimal fractional Maxwell model parameters asymptotically converge to parameters independent of these sampling points. The robustness of the identified model to the measurement disturbances was demonstrated by analytical analysis and numerical studies.
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Affiliation(s)
- Anna Stankiewicz
- Department of Technology Fundamentals, Faculty of Production Engineering, University of Life Sciences in Lublin, 20-612 Lublin, Poland
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Vichare R, Crelli C, Liu L, Das AC, McCallin R, Zor F, Kulahci Y, Gorantla VS, Janjic JM. A Reversibly Thermoresponsive, Theranostic Nanoemulgel for Tacrolimus Delivery to Activated Macrophages: Formulation and In Vitro Validation. Pharmaceutics 2023; 15:2372. [PMID: 37896130 PMCID: PMC10610217 DOI: 10.3390/pharmaceutics15102372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/29/2023] Open
Abstract
Despite long-term immunosuppression, organ transplant recipients face the risk of immune rejection and graft loss. Tacrolimus (TAC, FK506, Prograf®) is an FDA-approved keystone immunosuppressant for preventing transplant rejection. However, it undergoes extensive first-pass metabolism and has a narrow therapeutic window, which leads to erratic bioavailability and toxicity. Local delivery of TAC directly into the graft, instead of systemic delivery, can improve safety, efficacy, and tolerability. Macrophages have emerged as promising therapeutic targets as their increased levels correlate with an increased risk of organ rejection and a poor prognosis post-transplantation. Here, we present a locally injectable drug delivery platform for macrophages, where TAC is incorporated into a colloidally stable nanoemulsion and then formulated as a reversibly thermoresponsive, pluronic-based nanoemulgel (NEG). This novel formulation is designed to undergo a sol-to-gel transition at physiological temperature to sustain TAC release in situ at the site of local application. We also show that TAC-NEG mitigates the release of proinflammatory cytokines and nitric oxide from lipopolysaccharide (LPS)-activated macrophages. To the best of our knowledge, this is the first TAC-loaded nanoemulgel with demonstrated anti-inflammatory effects on macrophages in vitro.
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Affiliation(s)
- Riddhi Vichare
- School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA; (R.V.); (C.C.); (L.L.); (A.C.D.); (R.M.)
| | - Caitlin Crelli
- School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA; (R.V.); (C.C.); (L.L.); (A.C.D.); (R.M.)
| | - Lu Liu
- School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA; (R.V.); (C.C.); (L.L.); (A.C.D.); (R.M.)
| | - Amit Chandra Das
- School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA; (R.V.); (C.C.); (L.L.); (A.C.D.); (R.M.)
| | - Rebecca McCallin
- School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA; (R.V.); (C.C.); (L.L.); (A.C.D.); (R.M.)
| | - Fatih Zor
- Wake Forest School of Medicine, Wake Forest Institute of Regenerative Medicine, Winston Salem, NC 27101, USA; (F.Z.); (Y.K.); (V.S.G.)
| | - Yalcin Kulahci
- Wake Forest School of Medicine, Wake Forest Institute of Regenerative Medicine, Winston Salem, NC 27101, USA; (F.Z.); (Y.K.); (V.S.G.)
| | - Vijay S. Gorantla
- Wake Forest School of Medicine, Wake Forest Institute of Regenerative Medicine, Winston Salem, NC 27101, USA; (F.Z.); (Y.K.); (V.S.G.)
| | - Jelena M. Janjic
- School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA; (R.V.); (C.C.); (L.L.); (A.C.D.); (R.M.)
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Vichare R, Crelli C, Liu L, McCallin R, Cowan A, Stratimirovic S, Herneisey M, Pollock JA, Janjic JM. Folate-conjugated near-infrared fluorescent perfluorocarbon nanoemulsions as theranostics for activated macrophage COX-2 inhibition. Sci Rep 2023; 13:15229. [PMID: 37709807 PMCID: PMC10502124 DOI: 10.1038/s41598-023-41959-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/04/2023] [Indexed: 09/16/2023] Open
Abstract
Activated macrophages play a critical role in the orchestration of inflammation and inflammatory pain in several chronic diseases. We present here the first perfluorocarbon nanoemulsion (PFC NE) that is designed to preferentially target activated macrophages and can deliver up to three payloads (two fluorescent dyes and a COX-2 inhibitor). Folate receptors are overexpressed on activated macrophages. Therefore, we introduced a folate-PEG-cholesterol conjugate into the formulation. The incorporation of folate conjugate did not require changes in processing parameters and did not change the droplet size or fluorescent properties of the PFC NE. The uptake of folate-conjugated PFC NE was higher in activated macrophages than in resting macrophages. Flow cytometry showed that the uptake of folate-conjugated PFC NE occurred by both phagocytosis and receptor-mediated endocytosis. Furthermore, folate-conjugated PFC NE inhibited the release of proinflammatory cytokines (TNF-α and IL-6) more effectively than nonmodified PFC NE, while drug loading and COX-2 inhibition were comparable. The PFC NEs reported here were successfully produced on multiple scales, from 25 to 200 mL, and by using two distinct processors (microfluidizers: M110S and LM20). Therefore, folate-conjugated PFC NEs are viable anti-inflammatory theranostic nanosystems for macrophage drug delivery and imaging.
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Affiliation(s)
- Riddhi Vichare
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Caitlin Crelli
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Lu Liu
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Rebecca McCallin
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Abree Cowan
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Stefan Stratimirovic
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Michele Herneisey
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA
| | - John A Pollock
- Department of Biological Sciences, School of Science and Engineering, Duquesne University, Pittsburgh, PA, 15282, USA
| | - Jelena M Janjic
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA, 15282, USA.
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Toor R, Denoyel R, Liggieri L, Schmitt M, Antoni M. Influence of Surfactant Concentration on Spontaneous Emulsification Kinetics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11521-11528. [PMID: 36095327 DOI: 10.1021/acs.langmuir.1c03443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The kinetics of spontaneous emulsification is investigated on aqueous pendant drops in paraffin oil. Optical microscopy in transmission mode is used for high-spatial-resolution image recording. The influence of a lipophilic surfactant (Span 80) and two water-soluble surfactants (CTAB and SDS) is investigated. As time runs, the drop interface turns opaque due to the formation of microstructures associated with spontaneous emulsification. The time evolution of this phenomenon is shown to depend upon temperature and surfactant concentration, which leads to an overall shrinkage due to gradual water uptake and transport into paraffin oil. Spontaneous emulsification kinetics depends upon the chemical composition. Higher concentrations of Span 80 and CTAB (resp. SDS) are shown to promote (resp. hinder) water transport. This work provides new insights into the understanding of spontaneous emulsification when combining the properties of non-ionic and ionic surfactants.
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Affiliation(s)
- Ritu Toor
- Aix-Marseille Univ., CNRS, MADIREL, Marseille 13013, France
| | - Renaud Denoyel
- Aix-Marseille Univ., CNRS, MADIREL, Marseille 13013, France
| | - Libero Liggieri
- CNR-Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Unit of Genoa, Genova 16149, Italy
| | | | - Mickaël Antoni
- Aix-Marseille Univ., CNRS, MADIREL, Marseille 13013, France
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Salt effects on the dilational viscoelasticity of surfactant adsorption layers. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2021.101538] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Al Najjar T, Allam NK, El Sawy EN. Anionic/nonionic surfactants for controlled synthesis of highly concentrated sub-50 nm polystyrene spheres. NANOSCALE ADVANCES 2021; 3:5626-5635. [PMID: 36133261 PMCID: PMC9417686 DOI: 10.1039/d1na00438g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 08/10/2021] [Indexed: 06/16/2023]
Abstract
Polystyrene nanospheres are of great importance in 3D hard templating along with many other fields like pharmaceuticals and coatings. Therefore, it is important to be able to prepare polystyrene beads with different sphere sizes that suit each application. In this work, the emulsion polymerization method was used to prepare monodispersed polystyrene (PS) spheres with an average size of 50 nm, using styrene monomer, sodium dodecyl sulfate (SDS) and polyvinylpyrrolidone (PVP) as surfactants, and potassium persulfate (KPS) as the initiator. The average size and size distribution of the PS spheres were controlled by optimizing the synthesis parameters such as the concentration of the monomer, initiator, and surfactant, the type of surfactant, and the time and temperature of polymerization. The shape, size, and size distribution of the prepared PS spheres were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The preparation of perfectly spherical PS spheres as small as 50 nm with a narrow size distribution is obtained using 8% styrene with (5% SDS and 2% KPS of the styrene amount) at 90 °C, with the monomer and surfactant molar ratio and concentration and the polymerization temperature being the dominating factors that affect the PS bead size.
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Affiliation(s)
- Taher Al Najjar
- Department of Chemistry, School of Sciences and Engineering, The American University in Cairo New Cairo 11835 Egypt
| | - Nageh K Allam
- Energy Materials Laboratory, School of Sciences and Engineering, The American University in Cairo New Cairo 11835 Egypt
| | - Ehab N El Sawy
- Department of Chemistry, School of Sciences and Engineering, The American University in Cairo New Cairo 11835 Egypt
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Thermodynamics, Kinetics and Dilational Visco-Elasticity of Adsorbed CnEOm Layers at the Aqueous Solution/Air Interface. COLLOIDS AND INTERFACES 2021. [DOI: 10.3390/colloids5010016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The adsorption behaviour of linear poly(oxyethylene) alkyl ether (CnEOm) is best described by a reorientation model. Based on a complete set of experimental data, including the adsorption kinetics, the equilibrium surface tension isotherm and the surface dilational visco-elasticity, the thermodynamic and kinetic adsorption parameters for some CnEOm at the water/air interface were determined. For the study, six CnEOm surfactants were selected (n = 10, 12 and 14 and m = 4, 5 and 8) and were studied by bubble profile analysis and maximum bubble pressure tensiometry. A refined theoretical model based on a reorientation-adsorption model combined with a diffusion-controlled adsorption kinetics and exchange of matter allowed us to calculate the surface layer composition by adsorbing molecules in different orientations. It turns out that at larger surface coverage, the adsorption rate decreases, i.e., the apparent diffusion coefficients are smaller. This deceleration can be explained by the transition of molecules adsorbed in a state of larger molar surface area into a state with smaller molar surface area.
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