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De Luca S, Treny J, Chen F, Seal P, Stenzel MH, Smith SC. Enhancing Cationic Drug Delivery with Polymeric Carriers: The Coulomb‐pH Switch Approach. Adv Theory Simul 2020. [DOI: 10.1002/adts.202000247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Sergio De Luca
- Research School of Physics and Engineering The Australian National University Canberra ACT 2601 Australia
| | - Jennifer Treny
- Centre for Advanced Macromolecular Design School of Chemistry The University of New South Wales Sydney NSW 2052 Australia
| | - Fan Chen
- Centre for Advanced Macromolecular Design School of Chemistry The University of New South Wales Sydney NSW 2052 Australia
| | - Prasenjit Seal
- Department of Chemistry University of Helsinki P.O. Box 55 (A.I. Virtasen aukio 1) Helsinki 00014 Finland
| | - Martina H. Stenzel
- Centre for Advanced Macromolecular Design School of Chemistry The University of New South Wales Sydney NSW 2052 Australia
| | - Sean C. Smith
- Research School of Physics and Engineering The Australian National University Canberra ACT 2601 Australia
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Wong S, Zhao J, Cao C, Wong CK, Kuchel RP, De Luca S, Hook JM, Garvey CJ, Smith S, Ho J, Stenzel MH. Just add sugar for carbohydrate induced self-assembly of curcumin. Nat Commun 2019; 10:582. [PMID: 30718496 PMCID: PMC6362107 DOI: 10.1038/s41467-019-08402-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/04/2019] [Indexed: 11/24/2022] Open
Abstract
In nature, self-assembly processes based on amphiphilic molecules play an integral part in the design of structures of higher order such as cells. Among them, amphiphilic glycoproteins or glycolipids take on a pivotal role due to their bioactivity. Here we show that sugars, in particular, fructose, are capable of directing the self-assembly of highly insoluble curcumin resulting in the formation of well-defined capsules based on non-covalent forces. Simply by mixing an aqueous solution of fructose and curcumin in an open vessel leads to the generation of capsules with sizes ranging between 100 and 150 nm independent of the initial concentrations used. Our results demonstrate that hydrogen bonding displayed by fructose can induce the self-assembly of hydrophobic molecules such as curcumin into well-ordered structures, and serving as a simple and virtually instantaneous way of making nanoparticles from curcumin in water with the potential for template polymerization and nanocarriers.
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Affiliation(s)
- Sandy Wong
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia
| | - Jiacheng Zhao
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia
| | - Cheng Cao
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia
| | - Chin Ken Wong
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia
| | - Rhiannon P Kuchel
- Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Sergio De Luca
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - James M Hook
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia
- Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Christopher J Garvey
- Australian Centre for Neutron Scattering, ANSTO, Lucas Heights, NSW, 2234, Australia
| | - Sean Smith
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
- Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University, Canberra, ANU, Australia
| | - Junming Ho
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia
| | - Martina H Stenzel
- School of Chemistry, Centre for Advanced Macromolecular Design (CAMD), University of New South Wales, Sydney, NSW, 2052, Australia.
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De Luca S, Chen F, Seal P, Stenzel MH, Smith SC. Binding and Release between Polymeric Carrier and Protein Drug: pH-Mediated Interplay of Coulomb Forces, Hydrogen Bonding, van der Waals Interactions, and Entropy. Biomacromolecules 2017; 18:3665-3677. [PMID: 28880549 DOI: 10.1021/acs.biomac.7b00657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The accelerating search for new types of drugs and delivery strategies poses challenge to understanding the mechanism of delivery. To this end, a detailed atomistic picture of binding between the drug and carrier is quintessential. Although many studies focus on the electrostatics of drug-vector interactions, it has also been pointed out that entropic factors relating to water and counterions can play an important role. By carrying out extensive molecular dynamics simulations and subsequently validating with experiments, we shed light herein on the binding in aqueous solution between a protein drug and polymeric carrier. We examined the complexation between the polymer poly(ethylene glycol) methyl ether acrylate-b-poly(carboxyethyl acrylate (PEGMEA-b-PCEA) and the protein egg white lysozyme, a system that acts as a model for polymer-vector/protein-drug delivery systems. The complexation has been visualized and characterized using contact maps and hydrogen bonding analyses for five independent simulations of the complex, each running over 100 ns. Binding at physiological pH is, as expected, mediated by Coulombic attraction between the positively charged protein and negatively charged carboxylate groups on the polymer. However, we find that consideration of electrostatics alone is insufficient to explain the complexation behavior at low pH. Intracomplex hydrogen bonds, van der Waals interactions, as well as water-water interactions dictate that the polymer does not release the protein at pH 4.8 or indeed at pH 3.2 even though the Coulombic attractions are largely removed as carboxylate groups on the polymer become titrated. Experiments in aqueous solution carried out at pH 7.0, 4.5, and 3.0 confirm the veracity of the computed binding behavior. Overall, these combined simulation and experimental results illustrate that coulomb interactions need to be complemented with consideration of other entropic forces, mediated by van der Waals interactions and hydrogen bonding, to search for adequate descriptors to predict binding and release properties of polymer-protein complexes. Advances in computational power over the past decade make atomistic molecular dynamics simulations such as implemented here one of the few avenues currently available to elucidate the complexity of these interactions and provide insights toward finding adequate descriptors. Thus, there remains much room for improvement of design principles for efficient capture and release delivery systems.
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Affiliation(s)
- Sergio De Luca
- Integrated Material Design Centre (IMDC), School of Chemical Engineering and ‡Centre for Advanced Macromolecular Design, School of Chemical Engineering and School of Chemistry, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Fan Chen
- Integrated Material Design Centre (IMDC), School of Chemical Engineering and ‡Centre for Advanced Macromolecular Design, School of Chemical Engineering and School of Chemistry, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Prasenjit Seal
- Integrated Material Design Centre (IMDC), School of Chemical Engineering and ‡Centre for Advanced Macromolecular Design, School of Chemical Engineering and School of Chemistry, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Martina H Stenzel
- Integrated Material Design Centre (IMDC), School of Chemical Engineering and ‡Centre for Advanced Macromolecular Design, School of Chemical Engineering and School of Chemistry, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Sean C Smith
- Integrated Material Design Centre (IMDC), School of Chemical Engineering and ‡Centre for Advanced Macromolecular Design, School of Chemical Engineering and School of Chemistry, The University of New South Wales , Sydney, New South Wales 2052, Australia
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De Luca S, Seal P, Ouyang D, Parekh HS, Kannam SK, Smith SC. Dynamical Interactions of 5-Fluorouracil Drug with Dendritic Peptide Vectors: The Impact of Dendrimer Generation, Charge, Counterions, and Structured Water. J Phys Chem B 2016; 120:5732-43. [PMID: 27267604 DOI: 10.1021/acs.jpcb.6b00533] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Molecular dynamics simulations are utilized to investigate the interactions between the skin cancer drug 5-fluorouracil (5FU) and peptide-based dendritic carrier systems. We find that these drug-carrier interactions do not conform to the traditional picture of long-time retention of the drug within a hydrophobic core of the dendrimer carrier. Rather, 5FU, which is moderately soluble in its own right, experiences weak, transient chattering interactions all over the dendrimer, mediated through multiple short-lived hydrogen bonding and close contact events. We find that charge on the periphery of the dendrimer actually has a negative effect on the frequency of drug-carrier interactions due to a counterion screening effect that has not previously been observed. However, charge is nevertheless an important feature since neutral dendrimers are shown to have a significant mutual attraction that can lead to clustering or agglomeration. This clustering is prevented due to charge repulsion for the titrated dendrimers, such that they remain independent in solution.
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Affiliation(s)
- Sergio De Luca
- Integrated Materials Design Centre (IMDC), School of Chemical Engineering, UNSW Australia , Sydney, New South Wales 2052, Australia
| | - Prasenjit Seal
- Integrated Materials Design Centre (IMDC), School of Chemical Engineering, UNSW Australia , Sydney, New South Wales 2052, Australia
| | - Defang Ouyang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences (ICMS), University of Macau , Macau, China
| | - Harendra S Parekh
- School of Pharmacy, The University of Queensland , Brisbane, Queensland 4072, Australia
| | | | - Sean C Smith
- Integrated Materials Design Centre (IMDC), School of Chemical Engineering, UNSW Australia , Sydney, New South Wales 2052, Australia
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De Luca S, Kannam SK, Todd BD, Frascoli F, Hansen JS, Daivis PJ. Effects of Confinement on the Dielectric Response of Water Extends up to Mesoscale Dimensions. Langmuir 2016; 32:4765-4773. [PMID: 27115841 DOI: 10.1021/acs.langmuir.6b00791] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The extent of confinement effects on water is not clear in the literature. While some properties are affected only within a few nanometers from the wall surface, others are affected over long length scales, but the range is not clear. In this work, we have examined the dielectric response of confined water under the influence of external electric fields along with the dipolar fluctuations at equilibrium. The confinement induces a strong anisotropic effect which is evident up to 100 nm channel width, and may extend to macroscopic dimensions. The root-mean-square fluctuations of the total orientational dipole moment in the direction perpendicular to the surfaces is 1 order of magnitude smaller than the value attained in the parallel direction and is independent of the channel width. Consequently, the isotropic condition is unlikely to be recovered until the channel width reaches macroscopic dimensions. Consistent with dipole moment fluctuations, the effect of confinement on the dielectric response also persists up to channel widths considerably beyond 100 nm. When an electric field is applied in the perpendicular direction, the orientational relaxation is 3 orders of magnitude faster than the dipolar relaxation in the parallel direction and independent of temperature.
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Affiliation(s)
- Sergio De Luca
- School of Chemical Engineering, Integrated Material Design Centre (IMDC), University of New South Wales , Sydney, NSW 2033, Australia
| | | | | | | | - J S Hansen
- DNRF Center "Glass and Time", IMFUFA, Department of Science and Environment, Roskilde University , DK-4000 Roskilde, Denmark
| | - Peter J Daivis
- School of Applied Sciences, RMIT University , Melbourne, Victoria 3001, Australia
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De Luca S, Todd BD, Hansen JS, Daivis PJ. Molecular dynamics study of nanoconfined water flow driven by rotating electric fields under realistic experimental conditions. Langmuir 2014; 30:3095-3109. [PMID: 24575940 DOI: 10.1021/la404805s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In our recent work, J. Chem. Phys. 2013, 138, 154712, we demonstrated the feasibility of unidirectional pumping of water, exploiting translational-rotational momentum coupling using nonequilibrium molecular dynamics simulations. Flow can be sustained when the fluid is driven out of equilibrium by an external spatially uniform rotating electric field and confined between two planar surfaces exposing different degrees of hydrophobicity. The permanent dipole moment of water follows the rotating field, thus inducing the molecules to spin, and the torque exerted by the field is continuously injected into the fluid, enabling a steady conversion of spin angular momentum into linear momentum. The translational-rotational coupling is a sensitive function of the rotating electric field parameters. In this work, we have found that there exists a small energy dissipation region attainable when the frequency of the rotating electric field matches the inverse of the dielectric relaxation time of water and when its amplitude lies in a range just before dielectric saturation effects take place. In this region, that is, when the frequency lies in a small window of the microwave region around ∼20 GHz and amplitude ∼0.03 V Å(-1), the translational-rotational coupling is most effective, yielding fluid velocities of magnitudes of ∼2 ms(-1) with only moderate fluid heating. In this work, we also confine water to a realistic nanochannel made of graphene giving a hydrophobic surface on one side and β-cristobalite giving a hydrophilic surface on the other, reproducing slip-and-stick velocity boundary conditions, respectively. This enables us to demonstrate that in a realistic environment, the coupling can be effectively exploited to achieve noncontact pumping of water at the nanoscale. A quantitative comparison between nonequilibrium molecular dynamics and analytical solutions of the extended Navier-Stokes equations, including an external rotating electric field has been performed, showing excellent agreement when the electric field parameters match the aforementioned small energy dissipation region.
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Affiliation(s)
- Sergio De Luca
- Department of Mathematics, Faculty of Science, Engineering and Technology, and Centre for Molecular Simulation, Swinburne University of Technology , Melbourne, Victoria 3122, Australia
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Abstract
Pumping of fluids confined to nanometer dimension spaces is a technically challenging yet vitally important technological application with far reaching consequences for lab-on-a-chip devices, biomimetic nanoscale reactors, nanoscale filtration devices and the like. All current pumping mechanisms require some sort of direct intrusion into the nanofluidic system, and involve mechanical or electronic components. In this paper, we present the first nonequilibrium molecular dynamics results to demonstrate that non-intrusive electropumping of liquid water on the nanoscale can be performed by subtly exploiting the coupling of spin angular momentum to linear streaming momentum. A spatially uniform rotating electric field is applied to water molecules, which couples to their permanent electric dipole moments. The resulting molecular rotational momentum is converted into linear streaming momentum of the fluid. By selectively tuning the degree of hydrophobicity of the solid walls one can generate a net unidirectional flow. Our results for the linear streaming and angular velocities of the confined water are in general agreement with the extended hydrodynamical theory for this process, though also suggest refinements to the theory are required. These numerical experiments confirm that this new concept for pumping of polar nanofluids can be employed under laboratory conditions, opening up significant new technological possibilities.
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Affiliation(s)
- Sergio De Luca
- Mathematics, Faculty of Engineering and Industrial Sciences, and Centre for Molecular Simulation, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
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Avrova AO, Whisson SC, Pritchard L, Venter E, De Luca S, Hein I, Birch PRJ. A novel non-protein-coding infection-specific gene family is clustered throughout the genome of Phytophthora infestans. Microbiology (Reading) 2007; 153:747-59. [PMID: 17322195 DOI: 10.1099/mic.0.2006/002220-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phytophthora infestans is the cause of late blight, a devastating and re-emerging disease of potato. Significant advances have been made in understanding the biology of P. infestans, and in the development of molecular tools to study this oomycete. Nevertheless, little is known about the molecular bases of the establishment or development of disease in this hemibiotrophic pathogen. Suppression subtractive hybridization (SSH) was used to generate cDNA enriched for sequences upregulated during potato infection. To identify pathogen-derived cDNAs, and eliminate host sequences from further study, SSH cDNA was hybridized to a P. infestans bacterial artificial chromosome library. A new gene family was identified called Pinci1, comprising more than 400 members arranged in clusters of up to nine copies throughout the P. infestans draft genome sequence. Real-time RT-PCR was used to quantify the expression of five classes of transcript within the family, relative to the constitutively expressed PiactA gene, and it revealed them to be significantly upregulated from 12 to 33 h post-inoculation, a period defining the biotrophic phase of infection. Computational analysis of sequences suggested that transcripts were non-protein coding, and this was confirmed by transient expression of FLAG-tagged ORFs in P. infestans.
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Affiliation(s)
- Anna O Avrova
- Plant Pathology Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK
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