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Heteromultivalent peptide recognition by co-assembly of cyclodextrin and calixarene amphiphiles enables inhibition of amyloid fibrillation. Nat Chem 2018; 11:86-93. [DOI: 10.1038/s41557-018-0164-y] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 09/21/2018] [Indexed: 01/22/2023]
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2
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Du Y, Jin J, Jiang W. A study of polyethylene glycol backfilling for enhancing target recognition using QCM-D and DPI. J Mater Chem B 2018; 6:6217-6224. [PMID: 32254612 DOI: 10.1039/c8tb01526k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Polyethylene glycol (PEG) is a promising candidate for protein resistance and preserving protein function in biomedical applications. In this study, a PEG-based bifunctional platform with antifouling for plasma proteins and high sensitivity for biomolecules was designed. Long PEG chains (PEG24) were used to install functional biomolecules, and short PEG chains (PEG4) served as a protective layer to backfill the surface and suppress nonspecific protein adsorption. Quartz crystal microbalance with dissipation (QCM-D) and dual polarization interferometry (DPI) were combined to investigate the dynamic process of PEG4 backfilling and the recognition capacity of biomolecules with different ratios of PEG4 and PEG24 in real time. The amount of PEG4 chain backfilling affected the flexibility of PEG24 and exposed sites. The recognition capacity was improved by increasing the ratios of PEG4 to PEG24. Therefore, when the feeding ratio of PEG4 to PEG24 was 9 : 1, a highly efficient and sensitive platform was constructed for immobilization of antibodies and recognition of antigens either in pure PBS or in a complex biological environment.
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Affiliation(s)
- Yanqiu Du
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
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3
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Guskova O, Savchenko V, König U, Uhlmann P, Sommer JU. How do immobilised cell-adhesive Arg–Gly–Asp-containing peptides behave at the PAA brush surface? MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1502429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Olga Guskova
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Dresden Center for Computational Materials Science, Technische Universität Dresden, Dresden, Germany
| | - Vladyslav Savchenko
- Fakultät Umweltwissenschaften, Technische Universität Dresden, Dresden, Germany
| | - Ulla König
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
| | - Petra Uhlmann
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Jens-Uwe Sommer
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Dresden Center for Computational Materials Science, Technische Universität Dresden, Dresden, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, Dresden, Germany
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4
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Wang W, Voigt A, Sundmacher K. The interaction of protein-coated bionanoparticles and surface receptors reevaluated: how important is the number of bonds? SOFT MATTER 2016; 12:6451-6462. [PMID: 27411954 DOI: 10.1039/c6sm00995f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Specifically designed bionanoparticles with a function-oriented protein-coating layer interact with self-prepared receptor surfaces as the counterpart. Based on surface plasmon resonance biosensing experiments, a model framework is validated to estimate the number of bonds formed between these bionanoparticles and the receptor surface based on multivalent interactions. Our multi-site kinetic model is able to analyze the adsorption rate constants and the number of bonds from experimental data of natural and synthetic bionanoparticles. The influence of the mass transport on the adsorption kinetics is modeled including a diffusional boundary layer where a helpful analytical solution has been derived. Our model framework extends previous studies to include a higher number of bonds, ranging from 1 up to 1000. An almost linear relationship between the number of bonds and the adsorption amount of bionanoparticles makes the model framework suitable to predict, for example, ligand density and to further assess coating performance. The proposed model framework can serve as a design tool for multivalent interaction experiments under variable process conditions.
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Affiliation(s)
- Wenjing Wang
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, D-39106 Magdeburg, Germany.
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5
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Ishii T, Miyata K, Anraku Y, Naito M, Yi Y, Jinbo T, Takae S, Fukusato Y, Hori M, Osada K, Kataoka K. Enhanced target recognition of nanoparticles by cocktail PEGylation with chains of varying lengths. Chem Commun (Camb) 2016; 52:1517-9. [DOI: 10.1039/c5cc06661a] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Monodispersed gold nanoparticles (AuNPs) were simultaneously decorated with lactosylated and non-modified shorter poly(ethylene glycol)s (PEGs) to enhance their target recognition.
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6
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Li Z, Gorfe AA. Receptor-mediated membrane adhesion of lipid-polymer hybrid (LPH) nanoparticles studied by dissipative particle dynamics simulations. NANOSCALE 2015; 7:814-824. [PMID: 25438167 PMCID: PMC5048752 DOI: 10.1039/c4nr04834b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Lipid-polymer hybrid (LPH) nanoparticles represent a novel class of targeted drug delivery platforms that combine the advantages of liposomes and biodegradable polymeric nanoparticles. However, the molecular details of the interaction between LPHs and their target cell membranes remain poorly understood. We have investigated the receptor-mediated membrane adhesion process of a ligand-tethered LPH nanoparticle using extensive dissipative particle dynamics (DPD) simulations. We found that the spontaneous adhesion process follows a first-order kinetics characterized by two distinct stages: a rapid nanoparticle-membrane engagement, followed by a slow growth in the number of ligand-receptor pairs coupled with structural re-organization of both the nanoparticle and the membrane. The number of ligand-receptor pairs increases with the dynamic segregation of ligands and receptors toward the adhesion zone causing an out-of-plane deformation of the membrane. Moreover, the fluidity of the lipid shell allows for strong nanoparticle-membrane interactions to occur even when the ligand density is low. The LPH-membrane avidity is enhanced by the increased stability of each receptor-ligand pair due to the geometric confinement and the cooperative effect arising from multiple binding events. Thus, our results reveal the unique advantages of LPH nanoparticles as active cell-targeting nanocarriers and provide some general principles governing nanoparticle-cell interactions that may aid future design of LPHs with improved affinity and specificity for a given target of interest.
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7
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Santos JL, Herrera-Alonso M. Kinetically Arrested Assemblies of Architecturally Distinct Block Copolymers. Macromolecules 2013. [DOI: 10.1021/ma402047e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- José Luis Santos
- Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, Maryland 21218
| | - Margarita Herrera-Alonso
- Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, Maryland 21218
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8
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Hinestrosa JP, Alonzo J, Osa M, Kilbey SM. Solution Behavior of Polystyrene−Polyisoprene Miktoarm Block Copolymers in a Selective Solvent for Polyisoprene. Macromolecules 2010. [DOI: 10.1021/ma100428a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Juan Pablo Hinestrosa
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634
| | - Jose Alonzo
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634
| | - Masashi Osa
- Department of Polymer Chemistry, Kyoto University, Katsura, Kyoto, 615-8510, Japan
| | - S. Michael Kilbey
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
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9
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Wang S, Dormidontova EE. Nanoparticle design optimization for enhanced targeting: Monte Carlo simulations. Biomacromolecules 2010; 11:1785-95. [PMID: 20536119 PMCID: PMC2999362 DOI: 10.1021/bm100248e] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Using computer simulations, we systematically studied the influence of different design parameters of a spherical nanoparticle tethered with monovalent ligands on its efficiency of targeting planar cell surfaces containing mobile receptors. We investigate how the nanoparticle affinity can be affected by changing the binding energy, the percent of functionalization by ligands, tether length, grafting density, and nanoparticle core size. In general, using a longer tether length or increasing the number of tethered chains without increasing the number of ligands increases the conformational penalty for tether stretching/compression near the cell surface and leads to a decrease in targeting efficiency. At the same time, using longer tethers or a larger core size allows ligands to interact with receptors over a larger cell surface area, which can enhance the nanoparticle affinity toward the cell surface. We also discuss the selectivity of nanoparticle targeting of cells with a high receptor density. Based on the obtained results, we provide recommendations for improving the nanoparticle binding affinity and selectivity, which can guide future nanoparticle development for diagnostic and therapeutic purposes.
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Affiliation(s)
- Shihu Wang
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106
| | - Elena E. Dormidontova
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106
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10
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Djohari H, Dormidontova EE. Kinetics of nanoparticle targeting by dissipative particle dynamics simulations. Biomacromolecules 2010; 10:3089-97. [PMID: 19894765 DOI: 10.1021/bm900785c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Dissipative particle dynamics simulations are applied to study nanoparticle targeting to a cell surface containing a high concentration of receptors. We found that the normalized number of bound ligands follows an exponential growth function 1 - exp(-t/tau), with the lifetime tau increasing as a function of the binding strength. With increasing binding energy, the shape of the adsorbed nanoparticle becomes ellipsoidal due to a large number of stably bound ligands, most of which are positioned on the nanoparticle periphery. For a low degree of functionalization of homogeneously distributed ligands, the kinetics of nanoparticle attachment slows down due to interference by nonfunctional chains, the overall number of bound ligands at equilibrium decreases, although the stability of ligand attachment increases. Janus-like nanoparticles with functionalized chains positioned on one side of the nanoparticle exhibit more rapid binding to the cell surface with a large equilibrium number of stably bound ligands.
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Affiliation(s)
- Hadrian Djohari
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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11
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Duncanson WJ, Oum K, Eisenbrey JR, Cleveland RO, Wheatley MA, Wong JY. Targeted binding of PEG-lipid modified polymer ultrasound contrast agents with tiered surface architecture. Biotechnol Bioeng 2010; 106:501-6. [PMID: 20091738 PMCID: PMC2980833 DOI: 10.1002/bit.22678] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In order for site-directed polymer ultrasound contrast agents (UCAs) to provide acoustic enhancement at disease sites to distinguish normal tissue from diseased tissue, the surface of these agents must be functionalized with mixtures of grafted polymers. Here a combination of longer liganded polyethylene glycol (PEG)-lipids and shorter unliganded PEG-lipids were introduced into the oil phase of a modified solvent evaporation double emulsion method for preparing UCAs. UCAs with different lengths of both liganded and unliganded lipids were imaged under 7.5 MHz ultrasound. The B-mode image brightness of the mixed PEG-lipid UCAs was within 1 dB the brightness of the unliganded surface. After 15 min of continuous insonation, 70% of the contrast signal remained. The peptide arginine-glycine-aspartic acid (RGD) was added to the surface of these UCAs through a biotin-avidin linkage and binding was assessed under static and shear conditions. Binding was significant after 30 min of static incubation and the adherence of the UCA increased under shear flow from 3 UCA/cell (static) to 5 UCA/cell (shear).
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Affiliation(s)
| | - Kelleny Oum
- School of Biomedical Engineering, Science and Health Systems, Drexel University
| | - John R. Eisenbrey
- School of Biomedical Engineering, Science and Health Systems, Drexel University
| | | | | | - Joyce Y. Wong
- Department of Biomedical Engineering, Boston University
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12
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Ren CL, Carvajal D, Shull KR, Szleifer I. Streptavidin-biotin binding in the presence of a polymer spacer. A theoretical description. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:12283-92. [PMID: 19821628 PMCID: PMC2777891 DOI: 10.1021/la901735d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The binding of streptavidin to biotin located at the terminal ends of poly(ethylene oxide) tethered to a planar surface is studied using molecular theory. The theoretical model is applied to mimic experiments (Langmuir 2008, 24, 2472) performed using drop-shape analysis to study receptor-ligand binding at the oil/water interface. Our theoretical predictions show very good agreements with the experimental results. Furthermore, the theory enables us to study the thermodynamic and structural behavior of the PEO-biotin + streptavidin layer. The interfacial structure, shown by the volume fraction profiles of bound proteins and polymers, indicates that the proteins form a thick layer supported by stretched polymers, where the thickness of the layer is greater than the height of the protein. When the polymer spacer is composed of PEO (3000), a thick layer with multilayers of proteins is formed, supported by the stretched polymer chains. It was found that thick multilayers of proteins are formed when long spacers are present or at very high protein surface coverages on short spacers. This shows that the flexibility of the polymer spacer plays an important role in determining the structure of the bound proteins due to their ability to accommodate highly distorted conformations to optimize binding and protein interactions. Protein domains are predicted when the amount of bound proteins is small due to the existence of streptavidin-streptavidin attractive interactions. As the number of proteins is increased, the competition between attractive interactions and steric repulsions determines the stability and structure of the bound layer. The theory predicts that the competition between these two forces leads to a phase separation at higher protein concentrations. The point where this transition happens depends on both spacer length and protein surface coverage and is an important consideration for practical applications of these and other similar systems. If the goal is to maximize protein binding, it is favorable to be above the layer transition, as multiple layers can accommodate greater bound protein densities. On the other hand, if the goal is to use these bound proteins as a linker group to build more complex structures, such as when avidin or streptavidin serves as a linker between two biotinylated polymers or proteins, the optimum is to be below the layer transition such that all bound linker proteins are available for further binding.
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Affiliation(s)
- Chun-Lai Ren
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
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13
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Hagy MC, Wang S, Dormidontova EE. Optimization of functionalized polymer layers for specific targeting of mobile receptors on cell surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13037-47. [PMID: 18834163 PMCID: PMC2731659 DOI: 10.1021/la801935h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The reversible binding between a planar polymer layer functionalized by ligands and a planar cell surface containing different densities of mobile receptors has been studied by Monte Carlo simulations. Using the acceptance-ratio method, the distance-dependent profiles for the average number of ligands bound to receptors, the total free energy for the polymer layer-cell surface interaction and the interaction force were obtained. Four main design parameters for the polymer layer were considered: the degree of functionalization, chain degree of polymerization, polymer grafting density and the binding energy for the ligand-receptor interaction. We found that an increase in the degree of functionalization or in the absolute energy of ligand-receptor binding results in a larger number of ligands bound to the receptors, lower free energy, and stronger attractive force. Polymer layers composed of shorter chains were found to exhibit a deeper and narrower free energy profile and a larger attractive force, while longer tethers can interact with the cell surface at a larger and broader range of separation distances, in agreement with experimental observations. Our simulation results show that the increase in polymer grafting density from the mushroom to brush regime enhances the ligand availability and results in a stronger attractive force, increases the maximum binding distance, but exhibits a shallower free energy minimum due to the smaller tolerance to compression for polymer layers with high grafting density. We used two measures of the polymer layer binding affinity to the cell surface: the free energy minimum, related to the equilibrium binding constant and the fraction of bound ligands. We found that the polymer layers with a smaller chain length and grafting density, larger degree of functionalization, and larger absolute binding energy exhibit both a larger equilibrium binding constant to the cell surface and a larger average number of bound ligands, except for high binding energies when the maximum level of binding is reached independently of polymer length and grafting density. We showed that high binding specificity can be achieved by the polymer layers with intermediate ligand-receptor binding energies or an intermediate number of ligands, as a larger binding energy or number of ligands ensures a high binding affinity but lacks specificity while a smaller binding energy or number of ligands provides inadequate affinity. We found that the results for polymer layers with different properties follow a similar pattern when both high binding affinity to cells with high receptor density and high binding specificity are considered. As a result, the optimal design of the polymer layers can be achieved by using several different strategies, which are discussed.
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Affiliation(s)
- Matthew C. Hagy
- Department of Macromolecular Science and Engineering Case Western Reserve University, Cleveland, Ohio
| | - Shihu Wang
- Department of Macromolecular Science and Engineering Case Western Reserve University, Cleveland, Ohio
| | - Elena E. Dormidontova
- Department of Macromolecular Science and Engineering Case Western Reserve University, Cleveland, Ohio
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14
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Longo GS, Thompson DH, Szleifer I. Ligand-receptor interactions between surfaces: the role of binary polymer spacers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:10324-33. [PMID: 18698869 PMCID: PMC6885380 DOI: 10.1021/la8009699] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The interactions between a receptor-modified planar surface and a surface grafted with a bimodal polymer layer, where one of the polymer species is ligand functionalized, are studied using a molecular theory. The effects of changing the binding energy of the ligand-receptor pair, the polymer surface coverage, the composition, and molecular weight of both the unfunctionalized and ligand functionalized polymers on the interactions between the surfaces are investigated. Our findings show that bridging exists between the surfaces including when the molecular weight of the ligand-bearing polymer is smaller than that of the unfunctionalized polymer, even though the ligand is initially buried within the polymer layer. The distance at which the surfaces bind depends only on the molecular weight of the ligand-modified polymer, while the strength of the interaction at a given surface separation can be tuned by changing the molecular weight of the polymers, the total polymer surface coverage, and the fraction of ligated polymers. The composition of the bimodal layer alters the structure of the polymer layer, thereby influencing the strength of the steric repulsions between the surfaces. Our theoretical results show good agreement with experimental data. The present theoretical study can be used as guidelines for the design of surfaces with tailored abilities for tunning the binding strength and surface-ligand separation distances for polymer-grafted surfaces bearing specific targeting ligands.
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Affiliation(s)
- Gabriel S. Longo
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393
| | - David H. Thompson
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393
| | - I. Szleifer
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208
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Abstract
This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood-brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list "elementary" phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach.
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Affiliation(s)
- Ales Prokop
- Department of Chemical Engineering, 24th Avenue & Garland Avenues, 107 Olin Hall, Vanderbilt University, Nashville, Tennessee 37235, USA.
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16
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The effect of extensible PEG tethers on shielding between grafted thermo-responsive polymer chains and integrin–RGD binding. Biomaterials 2008; 29:3650-3655. [DOI: 10.1016/j.biomaterials.2008.05.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 05/27/2008] [Indexed: 11/20/2022]
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Duncanson WJ, Figa MA, Hallock K, Zalipsky S, Hamilton JA, Wong JY. Targeted binding of PLA microparticles with lipid-PEG-tethered ligands. Biomaterials 2007; 28:4991-9. [PMID: 17707503 PMCID: PMC2679848 DOI: 10.1016/j.biomaterials.2007.05.044] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 05/17/2007] [Indexed: 10/22/2022]
Abstract
Solid core polymeric particles are an attractive delivery vehicle as they can efficiently encapsulate drugs of different physical and chemical characteristics. However, the effective targeting of such particles for therapeutic purposes has been somewhat elusive. Here, we report novel polymeric particles comprised of poly(lactic acid) (PLA) with incorporated poly(ethylene glycol)-lipids (PEG-lipids). Particles are characterized for morphology, surface charge, and composition with field-emission scanning electron microscopy (FESEM), zeta potential measurements, and proton nuclear magnetic resonance ((1)H NMR) spectroscopy, respectively. The surface densities of PEG lipids determined by (1)H NMR and particle size distributions are consistent with scaling theory for adsorption of chains onto a surface. We observe significant binding of liganded PEG-lipid tethers when the molecular weight is greater than the unliganded PEG-lipids for significant binding events. Importantly, the binding is not completely lost when the unliganded PEG molecular weight is greater than the liganded PEG-lipid tether. We observe a similar trend for the lower affinity ligand (thioctic acid), but the degree of binding is significantly lower than the high affinity ligand (biotin). This novel technique used to fabricate these liganded particles combined with the lipid bilayer binding studies provides a platform for systematic optimization of particle binding.
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Affiliation(s)
- Wynter J. Duncanson
- Department of Biomedical Engineering, Boston University, 44 Cummington St., Boston, MA 02215 USA
| | - Michael A. Figa
- Department of Biomedical Engineering, Boston University, 44 Cummington St., Boston, MA 02215 USA
| | - Kevin Hallock
- Department of Physiology and Biophysics, Boston University Medical Center, 715 Albany St., Boston, MA 02118, USA\
| | - Samuel Zalipsky
- ALZA Corporation, 1900 Charleston Road, P.O. Box 7210, Mountain View, CA 94039, USA
| | - James A. Hamilton
- Department of Biomedical Engineering, Boston University, 44 Cummington St., Boston, MA 02215 USA
- Department of Physiology and Biophysics, Boston University Medical Center, 715 Albany St., Boston, MA 02118, USA\
| | - Joyce Y. Wong
- Department of Biomedical Engineering, Boston University, 44 Cummington St., Boston, MA 02215 USA
- Corresponding Author: Joyce Y. Wong, Boston University, Department of Biomedical Engineering, 44 Cummington St., Boston, MA 02215, , Tel: (617) 353-2374, Fax: (617) 353-6766
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18
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Zhao Z, Matsui H. Accurate immobilization of antibody-functionalized peptide nanotubes on protein-patterned arrays by optimizing their ligand-receptor interactions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:1390-3. [PMID: 17590881 PMCID: PMC6369532 DOI: 10.1002/smll.200700006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- Zheyuan Zhao
- Department of Chemistry and Biochemistry City University of NewYork, Hunter College NewYork, NY 10021 (USA), Fax: (+ 1) 212-650-3918
| | - Hiroshi Matsui
- Department of Chemistry and Biochemistry City University of NewYork, Hunter College NewYork, NY 10021 (USA), Fax: (+ 1) 212-650-3918
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19
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Abstract
Receptor-mediated cell adhesion plays a critical role in cell migration, proliferation, signaling, and survival. A number of diseases, including cancer, show a strong correlation between integrin activation and metastasis. A better understanding of cell adhesion is highly desirable for not only therapeutic but also a number of tissue engineering applications. While a number of computational models and experimental studies have addressed the issue of cell adhesion to surfaces, no model or theory has adequately addressed cell adhesion at the molecular level. In this paper, the authors present a thermodynamic model that addresses receptor-mediated cell adhesion at the molecular level. By incorporating the entropic, conformational, solvation, and long- and short-range interactive components of receptors and the extracellular matrix molecules, they are able to predict adhesive free energy as a function of a number of key variables such as surface coverage, interaction distance, molecule size, and solvent conditions. Their method allows them to compute the free energy of adhesion in a multicomponent system where they can simultaneously study adhesion receptors and ligands of different sizes, chemical identities, and conformational properties. The authors' results not only provide a fundamental understanding of adhesion at the molecular level but also suggest possible strategies for designing novel biomaterials.
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Affiliation(s)
- Tianyi Yang
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
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20
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Sutton D, Nasongkla N, Blanco E, Gao J. Functionalized micellar systems for cancer targeted drug delivery. Pharm Res 2007; 24:1029-46. [PMID: 17385025 DOI: 10.1007/s11095-006-9223-y] [Citation(s) in RCA: 372] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Accepted: 12/21/2006] [Indexed: 11/24/2022]
Abstract
Polymer micelles are rapidly becoming a powerful nanomedicine platform for cancer therapeutic applications due to their small size (10-100 nm), in vivo stability, ability to solubilize water insoluble anticancer drugs, and prolonged blood circulation times. Recent data from clinical trials with three micelle formulations have highlighted these and other pharmacokinetic advantages with reduced systemic toxicity and patient morbidity compared to conventional drug formulation. While the initial anti-tumor efficacy of these systems seems promising, a strong research impetus has been placed on micelle functionalization in order to achieve tumor targeting and site-specific drug release, with the hope of reaching a more pronounced tumor response. Hence, the purpose of this review is to draw attention to the new developments of multi-functional polymer micelles for cancer therapy with special focus on tumor targeting and controlled drug release strategies.
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Affiliation(s)
- Damon Sutton
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, Texas 75390, USA.
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Akinchina A, Linse P. Diblock polyampholytes grafted onto spherical particles: effect of stiffness, charge density, and grafting density. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:1465-72. [PMID: 17241074 DOI: 10.1021/la062481r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The structure of spherical brushes formed by symmetric diblock polyampholytes end-grafted onto small spherical particles in aqueous solution is examined within the framework of the so-called primitive model using Monte Carlo simulations. The properties of the two blocks are identical except for the sign of their charges. Three different chain flexibilities corresponding to flexible, semiflexible, and stiff blocks are considered at various polyampholyte linear charge densities and grafting densities. The link between the two blocks is flexible at all conditions, and the grafted segments are laterally mobile. Radial and lateral spatial distribution functions of different types and single-chain properties are analyzed. The brush structure strongly depends on the chain flexibility. With flexible chains, a disordered polyelectrolyte complex is formed at the surface of the particle, the complex becoming more compact at increasing linear charge density. With stiff blocks, the inner blocks are radially oriented. At low linear charged density, the outer blocks are orientationally disordered, whereas at increasing electrostatic interaction the two blocks of a polyampholyte are parallel and close to each other, leading to an ordered structure referred to as a polyampholyte star. As the grafting density is increased, the brush thickness responds differently for flexible and nonflexible chains, depending on a different balance between electrostatic interactions and excluded volume effects.
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Affiliation(s)
- Anna Akinchina
- Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden
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Moore NW, Kuhl TL. The role of flexible tethers in multiple ligand-receptor bond formation between curved surfaces. Biophys J 2006; 91:1675-87. [PMID: 16751237 PMCID: PMC1544319 DOI: 10.1529/biophysj.105.079871] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Accepted: 05/24/2006] [Indexed: 01/25/2023] Open
Abstract
Ligands mounted to surfaces via extensible tethers are present in nature and represent a growing class of molecules used to engineer adhesion in drug targeting, biosensing, self-assembling nanostructures, and in other biophysical research. Using a continuum approach with geometric and thermodynamic arguments, we derive a number of analytical expressions that relate key properties of single-tethered ligand-receptor interactions to multiple bond formation between curved surfaces. The theoretical predictions are in good agreement with measurements made with the surface forces apparatus. We establish that, when ligated, many tethers commonly used in biophysical research exhibit a discrete binding range that can be accurately measured with force spectroscopy. The distribution of bound ligated tethers is independent of the surfaces' interaction radius, R. The bridging force scales linearly with R, the tether's effective spring constant and grafting density, and with the ligand-receptor bond energy when the surfaces are in direct contact. These results are contrasted to bridging forces that evolve between plane-parallel geometries. Last, we show how our simple analytical reductions can be used to predict adhesive forces for STEALTH liposomes and other targeted and self-assembled nanoparticles.
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Affiliation(s)
- Nathan W Moore
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, USA.
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Ray C, Brown JR, Akhremitchev BB. Single-molecule Force Spectroscopy Measurements of “Hydrophobic Bond” between Tethered Hexadecane Molecules. J Phys Chem B 2006; 110:17578-83. [PMID: 16942101 DOI: 10.1021/jp063517r] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hydrophobic effect is important for many biological and technological processes. Despite progress in theory, experimental data clarifying water structure and the interaction between hydrophobic solutes at the nanometer scale are scarce due to the very low solubility of hydrophobic species. This article describes an AFM single molecule force spectroscopy method to probe the interaction between molecules with low solubility and reports measurements of the strength and the length scale of the "hydrophobic bond" between hexadecane molecules. Hexadecane molecules are tethered by flexible poly(ethylene glycol) linkers to AFM probes and substrates, removing the aggregation state uncertainty of solution-based approaches as well as spurious surface effects. A shorter hydrophilic polymer layer is added to increase the accessibility of hydrophobic molecules for the force spectroscopy measurements. Statistical analysis of the rupture forces yields a barrier width of 0.24 nm, and a dissociation rate of 1.1 s(-1). The results of single molecule measurements are related to the theoretical predictions of the free energy of cavitation in water and to the empirical model of micellization of nonionic surfactants. It is estimated that approximately one-quarter of each molecule's surface is hydrated during forced dissociation, consistent with an extended (nonglobular) conformation of the hexadecane molecules in the dimer.
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Affiliation(s)
- Chad Ray
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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Martin JI, Zhang CZ, Wang ZG. Polymer-tethered ligand-receptor interactions between surfaces. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/polb.20897] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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