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Langridge TD, Gemeinhart RA. Toward understanding polymer micelle stability: Density ultracentrifugation offers insight into polymer micelle stability in human fluids. J Control Release 2020; 319:157-167. [PMID: 31881319 PMCID: PMC6958513 DOI: 10.1016/j.jconrel.2019.12.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 01/01/2023]
Abstract
Micelles, as a class of drug delivery systems, are underrepresented among United States Food and Drug Administration approved drugs. A lack of clinical translation of these systems may be due to, in part, to a lack of understanding of micelle interactions with biologic fluids following injection. Despite the limited clinical translation, micelles remain an active area of research focus and pre-clinical development. The goal of the present study was to examine the stability of amphiphilic block copolymer micelles in biologic fluids to identify the properties and components of biologic fluids that influence micelle stability. Micelle stability, measured via Förster resonance energy transfer-based fluorescent spectrometry, was complemented with density ultracentrifugation to reveal the colocalized, or dissociated, state of the dye cargo after exposure to human biologic fluids. Polymeric micelles composed of poly(ethylene glycol-block-caprolactone) (mPEG-CL) and poly(ethylene glycol-block-lactide) (mPEG-LA) were unstable in fetal bovine serum, human serum and synovial fluid, with varying levels of instability observed in ascites and pleural fluid. All polymeric micelles exhibited stability in cerebrospinal fluid, highlighting the potential for local cerebro-spinal administration of micelles. Interestingly, mPEG2.2k-CL3.1k and mPEG2k-LA2.7k micelles favored dissolution whereas mPEG5.4k-LA28.5k micelles favored stability. Taken together, our data offers both quantitative and qualitative evidence for micelle stability within human biologic fluids and offers evidence of polymer micelle instability in biologic fluids that is not explained by either total protein content or total unsaturated lipid content. The results help to identify potential sites for local delivery where stability is maintained.
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Affiliation(s)
- Timothy D Langridge
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60612-7231, USA
| | - Richard A Gemeinhart
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60612-7231, USA; Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607-7052, USA; Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60607-7052, USA; Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612-4319, USA.
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Uttinger MJ, Heyn TR, Jandt U, Wawra SE, Winzer B, Keppler JK, Peukert W. Measurement of length distribution of beta-lactoglobulin fibrils by multiwavelength analytical ultracentrifugation. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:745-760. [PMID: 32006057 PMCID: PMC7701075 DOI: 10.1007/s00249-020-01421-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/19/2019] [Accepted: 01/03/2020] [Indexed: 11/24/2022]
Abstract
The whey protein beta-lactoglobulin is the building block of amyloid fibrils which exhibit a great potential in various applications. These include stabilization of gels or emulsions. During biotechnological processing, high shear forces lead to fragmentation of fibrils and therefore to smaller fibril lengths. To provide insight into such processes, pure straight amyloid fibril dispersions (prepared at pH 2) were produced and sheared using the rotor stator setup of an Ultra Turrax. In the first part of this work, the sedimentation properties of fragmented amyloid fibrils sheared at different stress levels were analyzed with mulitwavelength analytical ultracentrifugation (AUC). Sedimentation data analysis was carried out with the boundary condition that fragmented fibrils were of cylindrical shape, for which frictional properties are known. These results were compared with complementary atomic force microscopy (AFM) measurements. We demonstrate how the sedimentation coefficient distribution from AUC experiments is influenced by the underlying length and diameter distribution of amyloid fibrils. In the second part of this work, we show how to correlate the fibril size reduction kinetics with the applied rotor revolution and the resulting energy density, respectively, using modal values of the sedimentation coefficients obtained from AUC. Remarkably, the determined scaling laws for the size reduction are in agreement with the results for other material systems, such as emulsification processes or the size reduction of graphene oxide sheets.
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Affiliation(s)
- Maximilian J Uttinger
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Timon R Heyn
- Institute of Human Nutrition and Food Science, Division of Food Technology, Kiel University, 24118, Kiel, Germany
| | - Uwe Jandt
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Simon E Wawra
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Bettina Winzer
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Julia K Keppler
- Institute of Human Nutrition and Food Science, Division of Food Technology, Kiel University, 24118, Kiel, Germany.,Laboratory of Food Process Engineering, Wageningen University, Bornse Weilanden 9, 6708WG, Wageningen, P.O. Box 17, 6700 AA, Wageningen, The Netherlands
| | - Wolfgang Peukert
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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Uttinger MJ, Wawra SE, Guckeisen T, Walter J, Bear A, Thajudeen T, Sherwood PJ, Smith A, Wagemans AM, Stafford WF, Peukert W. A Comprehensive Brownian Dynamics Approach for the Determination of Non-ideality Parameters from Analytical Ultracentrifugation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11491-11502. [PMID: 31385708 DOI: 10.1021/acs.langmuir.9b01916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Brownian dynamics (BD) has been applied as a comprehensive tool to model sedimentation and diffusion of nanoparticles in analytical ultracentrifugation (AUC) experiments. In this article, we extend the BD algorithm by considering space-dependent diffusion and solvent compressibility. With this, the changes in the sedimentation and diffusion coefficient from altered solvent properties at increased pressures are accurately taken into account. Moreover, it is demonstrated how the concept of space-dependent diffusion is employed to describe concentration-dependent sedimentation and diffusion coefficients, in particular, through the Gralen coefficient and the second virial coefficient. The influence of thermodynamic nonideality on diffusional properties can be accurately simulated and agree with well-known evaluation tools. BD simulations for sedimentation equilibrium and sedimentation velocity (SV) AUC experiments including effects of hydrodynamic and thermodynamic nonideality are validated by global evaluation in SEDANAL. The interplay of solvent compressibility and retrieved nonideality parameters can be studied utilizing BD. Finally, the second virial coefficient is determined for lysozyme from SV AUC experiments and BD simulations and compared to membrane osmometry. These results are in line with DLVO theory. In summary, BD simulations are established for the validation of nonideal sedimentation in AUC providing a sound basis for the evaluation of complex interactions even in polydisperse systems.
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Affiliation(s)
- Maximilian J Uttinger
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems , Friedrich-Alexander-Universität Erlangen-Nürnberg , Haberstraße 9a , 91058 Erlangen , Germany
| | - Simon E Wawra
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems , Friedrich-Alexander-Universität Erlangen-Nürnberg , Haberstraße 9a , 91058 Erlangen , Germany
| | - Tobias Guckeisen
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems , Friedrich-Alexander-Universität Erlangen-Nürnberg , Haberstraße 9a , 91058 Erlangen , Germany
| | - Johannes Walter
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems , Friedrich-Alexander-Universität Erlangen-Nürnberg , Haberstraße 9a , 91058 Erlangen , Germany
| | - Andreas Bear
- PULS Group, Department of Physics, Interdisciplinary Center of Nanostructured Films , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Cauerstrasse 3 , 91058 Erlangen , Germany
| | - Thaseem Thajudeen
- School of Mechanical Sciences , Indian Institute of Technology Goa , Goa College of Engineering Campus , Farmagudi, 403401 Ponda , Goa , India
| | - Peter J Sherwood
- Interactive Technology Inc. , P.O. Box 2768, Oakland , 94602 California , United States
| | - Ana Smith
- PULS Group, Department of Physics, Interdisciplinary Center of Nanostructured Films , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Cauerstrasse 3 , 91058 Erlangen , Germany
| | - Anja M Wagemans
- Institute of Food Technology and Food Chemistry , Technical University Berlin , Königin Luise-Str. 22 , 14195 Berlin , Germany
| | - Walter F Stafford
- Department of Neurology , Harvard Medical School , 220 Longwood Avenue Goldenson Building , Boston , 02115 Massachusetts , United States
| | - Wolfgang Peukert
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems , Friedrich-Alexander-Universität Erlangen-Nürnberg , Haberstraße 9a , 91058 Erlangen , Germany
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