Skip to main content
Log in

Atomic scale design and three-dimensional simulation of ionic diffusive nanofluidic channels

  • Research Paper
  • Published:
Microfluidics and Nanofluidics Aims and scope Submit manuscript

Abstract

Recent advance in nanotechnology has led to rapid advances in nanofluidics, which has been established as a reliable means for a wide variety of applications, including molecular separation, detection, crystallization and biosynthesis. Although atomic and molecular level consideration is a key ingredient in experimental design and fabrication of nanofluidic systems, atomic and molecular modeling of nanofluidics is rare and most simulations at nanoscale are restricted to one or two dimensions in the literature, to our best knowledge. The present work introduces atomic scale design and three-dimensional (3D) simulation of ionic diffusive nanofluidic systems. We propose a variational multiscale framework to represent the nanochannel in discrete atomic and/or molecular detail while describing the ionic solute by continuum. Apart from the major electrostatic and entropic effects, the non-electrostatic interactions between the channel and solution, and among solvent molecules are accounted in our modeling. We derive generalized Poisson–Nernst–Planck equations for nanofluidic systems. Mathematical algorithms, such as Dirichlet-to-Neumann mapping and the matched interface and boundary methods, are developed to rigorously solve the aforementioned equations to the second-order accuracy in 3D realistic settings. Three ionic diffusive nanofluidic systems, including a negatively charged nanochannel, a bipolar nanochannel and a double-well nanochannel, are designed to investigate the impact of atomic charges to channel current, density distribution and electrostatic potential. Numerical findings, such as gating, ion depletion and inversion, are in good agreements with those from experimental measurements and numerical simulations in the literature.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Fig. 20

Similar content being viewed by others

References

  • Abgrall P, Nguyen NT (2008) Nanofluidic devices and their applications. Anal Chem 80(7):2326–2341

    Article  Google Scholar 

  • Adalsteinsson H, Debusschere BJ, Long KR, Najm HN (2008) Components for atomistic-to-continuum multiscale modeling of flow in micro- and nanofluidic systems. Sci Prog 16:297–313

    Google Scholar 

  • Bashford D, Case DA (2000) Generalized Born models of macromolecular solvation effects. Annu Rev Phys Chem 51:129–152

    Article  Google Scholar 

  • Bazant MZ, Thornton K, Ajdari A (2004) Diffuse-charge dynamics in electrochemical systems. Phys Rev E 70:021506

    Article  Google Scholar 

  • Bazant MZ, Kilic MS, Storey BD, Ajdari A (2009) Towards an understanding of induced-charge electrokinetics at large applied voltages in concentrated solutions. Adv Colloid Interface Sci 152:48–88

    Article  Google Scholar 

  • Bazant MZ, Storey BD, Kornyshev AA (2011) Double layer in ionic liquids: overscreening versus crowding. Phys Rev Lett 106:046102

    Article  Google Scholar 

  • Beglov D, Roux B (1996) Solvation of complex molecules in a polar liquid: an integral equation theory. J Chem Phys 104(21):8678–8689

    Article  Google Scholar 

  • Belgrader P, Okuzumi M, Pourahmadi F, Borkholder DA, Northrup MA (2000) A microfluidic cartridge to prepare spores for PCR analysis. Biosens Bioelectr 14:849–852

    Article  Google Scholar 

  • Branton D, Deamer DW, Marziali A, Bayley H, Benner SA, Butler T, Di Ventra M, Garaj S, Hibbs A, Huang X et al (2008) The potential and challenges of nanopore sequencing. Nat Biotechnol 26(10):1146–1153

    Article  Google Scholar 

  • Burch D, Bazant MZ (2009) Size-dependent spinodal and miscibility gaps for intercalation in nanoparticles. Nano Lett 9(11):3795–3800

    Article  Google Scholar 

  • Busath DD, Thulin CD, Hendershot RW, Phillips LR, Maughan P, Cole CD, Bingham NC, Morrison S, Baird LC, Hendershot RJ, Cotten M, Cross TA (1998) Noncontact dipole effects on channel permeation. I. Experiments with (5f-indole)trp\(^{13}\) Gramicidin A channels. Biophys J 75:2830–2844

    Article  Google Scholar 

  • Cervera J, Schiedt B, Ramirez P (2005) A Poisson/Nernst–Planck model for ionic transport through synthetic conical nanopores. EPL 71(1):35

    Article  Google Scholar 

  • Chang CC, Yang RJ (2009) A perspective on streaming current in silica nanofluidic channels: Poisson–Boltzmann model versus Poisson–Nernst–Planck model. J Colliod Interface Sci 339:517–520

    Article  Google Scholar 

  • Chen L, Conlisk AT (2008) Electroosmotic flow and particle transport in micro/nano nozzles and diffusers. Biomed Microdevices 10:289–289

    Article  Google Scholar 

  • Chen D, Wei GW (2012) Quantum dynamics in continuum for proton transport—generalized correlation. J Chem Phys 136:134109

    Article  Google Scholar 

  • Chen DP, Eisenberg RS, Jerome JW, Shu CW (1995) Hydrodynamic model of temperature change in open ionic channels. Biophys J 69:2304–2322

    Article  Google Scholar 

  • Chen Z, Baker NA, Wei GW (2010) Differential geometry based solvation models I: Eulerian formulation. J Comput Phys 229:8231–8258

    Article  MathSciNet  MATH  Google Scholar 

  • Chen Z, Baker NA, Wei GW (2011) Differential geometry based solvation models II: Lagrangian formulation. J Math Biol 63:1139–1200

    Article  MathSciNet  MATH  Google Scholar 

  • Chen D, Chen Z, Wei GW (2012a) Quantum dynamics in continuum for proton transport II: variational solvent–solute interface. Int J Numer Methods Biomed Eng 28:25–51

    Article  MATH  Google Scholar 

  • Chen Z, Zhao S, Chun J, Thomas DG, Baker NA, Bates PB, Wei GW (2012b) Variational approach for nonpolar solvation analysis. J Chem Phys 137:084101

    Article  Google Scholar 

  • Cheng L-J, Guo LJ (2010) Nanofluidic diodes. Chem Soc Rev 39(3):923–938

    Article  Google Scholar 

  • Chou T (2009) Enhancement of charged macromolecule capture by nanopores in a salt gradient. J Chem Phys 131:034703

    Article  Google Scholar 

  • Chu KT, Bazant MZ (2006) Nonlinear electrochemical relaxation around conductors. Phys Rev E 74:011501

    Article  Google Scholar 

  • Coalson RD, Kurnikova MG (2005) Poisson–Nernst–Planck theory approach to the calculation of current through biological ion channels. IEEE Trans NanoBiosci 4(1):81–93

    Article  Google Scholar 

  • Constantin D, Siwy ZS (2007) Poisson–Nernst–Planck model of ion current rectification through a nanofluidic diode. Phys Rev E 76:041202

    Article  Google Scholar 

  • Daiguji H (2010) Ion transport in nanofluidic channels. Chem Soc Rev 39(3):901–911

    Article  Google Scholar 

  • Daiguji H, Yang P, Majumdar A (2004) Ion transport in nanofluidic channels. Nano Lett 4(1):137–142

    Article  Google Scholar 

  • Daiguji H, Oka Y, Shirono K (2005) Nanofluidic diode and bipolar transistor. Nano Lett 5(11):2274–2280

    Article  Google Scholar 

  • Davis ME, McCammon JA (1990) Electrostatics in biomolecular structure and dynamics. Chem Rev 94:509–521

    Article  Google Scholar 

  • Dominy BN, Brooks CL III (1999) Development of a generalized Born model parameterization for proteins and nucleic acids. J Phys Chem B 103(18):3765–3773

    Article  Google Scholar 

  • Duffy DC, Gillis HL, Lin J, Sheppard NF, Kellogg GJ (1999) Microfabricated centrifugal microfluidic systems: characterization and multiple enzymatic assay. Anal Chem 71:5206–5212

    Article  Google Scholar 

  • Eijkel JC, van den Berg A (2005) Nanofluidics: what is it and what can we expect from it? Microfluid Nanofluid 1(3):249–267

    Article  Google Scholar 

  • Eisenberg BS, Chen D (1993) Poisson–Nernst–Planck (PNP) theory of an open ionic channel. Biophys J 64:A22

    Google Scholar 

  • Eisenberg BS, Hyon YK, Liu C (2010) Energy variational analysis of ions in water and channels: field theory for primitive models of complex ionic fluids. J Chem Phys 133:104104

    Article  Google Scholar 

  • Erickson D, Rockwood T, Emery T, Scherer A, Psaltis D (2006) Nanofluidic tuning of photonic crystal circuits. Opt Lett 31:59–61

    Article  Google Scholar 

  • Feng X, Xia KL, Tong YY, Wei G-W (2012) Geometric modeling of subcellular structures, organelles and large multiprotein complexes. Int J Numer Methods Biomed Eng 28:1198–1223

    Article  MathSciNet  Google Scholar 

  • Feng X, Xia KL, Tong YY, Wei GW (2013) Multiscale geometric modeling of macromolecules II: Lagrangian representation. J Comput Chem 34:2100–2120

    Article  Google Scholar 

  • Fogolari F, Briggs JM (1997) On the variational approach to Poisson–Boltzmann free energies. Chem Phys Lett 281:135–139

    Article  Google Scholar 

  • Fogolari F, Brigo A, Molinari H (2002) The Poisson–Boltzmann equation for biomolecular electrostatics: a tool for structural biology. J Mol Recognit 15(6):377–392

    Article  Google Scholar 

  • Fu JP, Schoch RB, Stevens AL, Tannenbaum SR, Han JY (2007) A patterned anisotropic nanofluidic sieving structure for continuous-flow separation of dna and proteins. Nat Nanotechnol 2:121–128

    Article  Google Scholar 

  • Fu JP, Mao P, Han JY (2009) Continuous-flow bioseparation using microfabricated anisotropic nanofluidic sieving structures. Nat Protoc 4:1681–1698

    Article  Google Scholar 

  • Geng W, Yu S, Wei GW (2007) Treatment of charge singularities in implicit solvent models. J Chem Phys 127:114106

    Article  Google Scholar 

  • Gilson MK, Davis ME, Luty BA, McCammon JA (1993) Computation of electrostatic forces on solvated molecules using the Poisson–Boltzmann equation. J Phys Chem 97(14):3591–3600

    Article  Google Scholar 

  • Grochowski P, Trylska J (2008) Continuum molecular electrostatics, salt effects, and counterion binding—a review of the Poisson–Boltzmann theory and its modifications. Biopolymers 89(2):93–113

    Article  Google Scholar 

  • Hadd AG, Jacobson SC, Ramsey JM (1999) Microfluidic assays of acetylcholinesterase inhibitors. Anal Chem 71:5206–5212

    Article  Google Scholar 

  • He Y, Gillespie D, Boda D, Vlassiouk I, Eisenberg BS, Siwy ZS (2009) Tuning transport properties of nanofluidic devices with local charge inversion. J Am Chem Soc 131:5194–5202

    Article  Google Scholar 

  • Hollerbach U, Chen DP, Eisenberg RS (2001) Two- and three-dimensional Poisson–Nernst–Planck simulations of current flow through Gramicidin A. J Sci Comput 16(4):373–409

    Article  MATH  Google Scholar 

  • Holm C, Kekicheff P, Podgornik R (2001) Electrostatic effects in soft matter and biophysics. NATO science series. Kluwer Academic Publishers, Boston

    Book  Google Scholar 

  • Holst MJ (1994) The Poisson–Boltzmann equation: analysis and multilevel numerical solution. Ph.D. thesis, Numerical Computing Group, University of Illinois at Urbana-Champaign

  • Huber DE, Markel ML, Pennathur S, Patel KD (2009) Oligonucleotide hybridization and free-solution electrokinetic separation in a nanofluidic device. Lab Chip 9:2933–2940

    Article  Google Scholar 

  • Hyon Y, Eisenberg BS, Liu C (2011) A mathematical model for the hard sphere repulsion in ionic solution. Commun Math Sci 9:459–475

    Article  MathSciNet  MATH  Google Scholar 

  • Isebe D, Nerin P (2013) Numerical simulation of particle dynamics in an orifice-electrode system. Application to counting and sizing by impedance measurement. Int J Numer Methods Biomed Eng 29:462–475

    Article  Google Scholar 

  • Jerome J (1995) Analysis of charge transport. Mathematical theory and approximation of semiconductor models. Springer, New York

    Google Scholar 

  • Kamholz AE, Weigl BH, Finlayson BA, Yager P (1999) Quantitative analysis of molecular interaction in a microfluidic channel: the t-sensor. Anal Chem 71:5340–5347

    Article  Google Scholar 

  • Karnik R, Castelino K, Fan R, Yang P, Majumdar A (2005) Effects of biological reactions and modifications on conductance of nanofluidic channels. Nano Lett 5:1638–1642

    Article  Google Scholar 

  • Karnik R, Duan C, Castelino K, Daiguji H, Majumdar A (2007) Rectification of ionic current in a nanofluidic diode. Nano Lett 7(3):547–551

    Article  Google Scholar 

  • Kilic MS, Bazant MZ, Ajdari A (2007) Steric effects in the dynamics of electrolytes at large applied voltages. II. Modified Poisson–Nernst–Planck equations. Phys. Rev. E 75:021503

    Article  Google Scholar 

  • Kim BY, Yang J, Gong MJ, Flachsbart BR, Shannon MA, Bohn PW, Sweedler JV (2009) Multidimensional separation of chiral amino acid mixtures in a multilayered three-dimensional hybrid microfluidic/nanofluidic device. J Anal Chem 81:2715–2722

    Article  Google Scholar 

  • Kurnikova MG, Coalson RD, Graf P, Nitzan A (1999) A lattice relaxation algorithm for three-dimensional Poisson–Nernst–Planck theory with application to ion transport through the Gramicidin A channel. Biophys J 76:642–656

    Article  Google Scholar 

  • Lamm G (2003) The Poisson–Boltzmann equation. In: Lipkowitz KB, Larter R, Cundari TR (eds) Reviews in computational chemistry. Wiley, Hoboken, pp 147–366

    Chapter  Google Scholar 

  • Levin Y (2002) Electrostatic correlations: from plasma to biology. Rep Prog Phys 65:1577–1632

    Article  Google Scholar 

  • Li L, Ismagilov RF (2010) Protein crystallization using microfluidic technologies based on valves, droplets, and slipchip. Annu Rev Biophys 39:139–158

    Article  Google Scholar 

  • Li SC, Hoyles M, Kuyucak S, Chung S-H (1998) Brownian dynamics study of ion transport in the vestibule of membrane channels. Biophys J 74(1):37–47

    Article  Google Scholar 

  • Li J, Gershow M, Stein D, Brandin E, Golovchenko J (2003) Dna molecules and configurations in a solid-state nanopore microscope. Nat Mater 2(9):611–615

    Article  Google Scholar 

  • Macounova K, Cabrera CR, Holl MR, Yager P (2000) Generation of natural PH gradients in microfluidic channels for use in isoelectric focusing. Anal Chem 72:3745–3751

    Article  Google Scholar 

  • Manciu M, Ruckenstein E (2003) On the chemical free energy of the electrical double layer. Langmuir 19(4):1114–1120

    Article  Google Scholar 

  • Mei Y, Ji CG, Zhang JZH (2006) A new quantum method for electrostatic solvation energy of protein. J Chem Phys 125:094906

    Article  Google Scholar 

  • Modi N, Winterhalter M, Kleinekathöfer U (2012) Computational modeling of ion transport through nanopores. Nanoscale 4(20):6166–6180

    Article  Google Scholar 

  • Mukhopadhyay R (2006) What does nanofluidics have to offer? Anal Chem 78(21):7379–7382

    Article  Google Scholar 

  • Netz RR, Orland H (2000) Beyond Poisson–Boltzmann: fluctuation effects and correlation functions. Eur Phys J E 1(2–3):203–214

    Article  Google Scholar 

  • Perry JM, Zhou K, Harms ZD, Jacobson SC (2010) Ion transport in nanofluidic funnels. ACS Nano 4(7):3897–3902

    Article  Google Scholar 

  • Pinho D, Lima R, Pereira AI, Gayubo F (2013) Automatic tracking of labeled red blood cells in microchannels. Int J Numer Methods Biomed Eng 29:977–987

    Article  MathSciNet  Google Scholar 

  • Pu Q, Yun J, Temkin H, Liu S (2004) Ion-enrichment and ion-depletion effect of nanochannel structures. Nano Lett 4(6):1099–1103

    Article  Google Scholar 

  • Roux B, Allen T, Berneche S, Im W (2004) Theoretical and computational models of biological ion channels. Q Rev Biophys 37(01):15–103

    Article  Google Scholar 

  • Schoch RB, Han J, Renaud P (2008) Transport phenomena in nanofluidics. Rev Mod Phys 80(3):839

    Article  Google Scholar 

  • Sharp KA, Honig B (1990a) Calculating total electrostatic energies with the nonlinear Poisson–Boltzmann equation. J Phys Chem 94:7684–7692

    Article  Google Scholar 

  • Sharp KA, Honig B (1990b) Electrostatic interactions in macromolecules—theory and applications. Annu Rev Biophys Biophys Chem 19:301–332

    Article  Google Scholar 

  • Siwy ZS, Howorka S (2010) Engineered voltage-responsive nanopores. Chem Soc Rev 39(3):1115–1132

    Article  Google Scholar 

  • Snider RF, Wei GW, Muga JG (1996a) Moderately dense gas quantum kinetic theory: transport coefficient expressions. J Chem Phys 105:3066–3078

    Article  Google Scholar 

  • Snider RF, Wei GW, Muga JG (1996b) Moderately dense gas quantum kinetic theory: aspects of pair correlations. J Chem Phys 105:3057–3065

    Article  Google Scholar 

  • Song JH, Evans R, Lin YY, Hsu BN, Fair RB (2009) A scaling model for electrowetting-on-dielectric microfluidic actuators. Microfluid Nanofluid 7:75–89

    Article  Google Scholar 

  • Sparreboom W, Van Den Berg A, Eijkel J (2009) Principles and applications of nanofluidic transport. Nat Nanotechnol 4(11):713–720

    Article  Google Scholar 

  • Stein D, Kruithof M, Dekker C (2004) Surface-charge-governed ion transport in nanofluidic channels. Phys Rev Lett 93(3):035901

    Article  Google Scholar 

  • Tomasi J, Mennucci B, Cammi R (2005) Quantum mechanical continuum solvation models. Chem Rev 105:2999–3093

    Article  Google Scholar 

  • Tu B, Chen MX, Xie Y, Zhang LB, Eisenberg B, Lu BZ (2013) A parallel finite element simulator for ion transport through three-dimensional ion channel systems. J Comput Chem 34:2065–2078

    Article  Google Scholar 

  • Turner SWP, Cabodi M, Craighead HG (2002) Confinement-induced entropic recoil of single DNA molecules in a nanofluidic structure. Phys Rev Lett 88:128103

    Article  Google Scholar 

  • Vlachy V (1999) Ionic effects beyond Poisson–Boltzmann theory. Annu Rev Phys Chem 50:145–165

    Article  Google Scholar 

  • Vlassiouk I, Smirnov S, Siwy Z (2008a) Ionic selectivity of single nanochannels. Nano Lett 8:1978–1985

    Article  Google Scholar 

  • Vlassiouk I, Smirnov S, Siwy Z (2008b) Nanofluidic ionic diodes. Comparison of analytical and numerical solutions. ACS Nano 2:1589–1602

    Article  Google Scholar 

  • Wang J, Lin M, Crenshaw A, Hutchinson A, Hicks B, Yeager M, Berndt S, Huang WY, Hayes RB, Chanock SJ, Jones RC, Ramakrishnan R (2009a) High-throughput single nucleotide polymorphism genotyping using nanofluidic dynamic arrays. BMC Genomics 10:561

    Article  Google Scholar 

  • Wang Y, Pant K, Chen ZJ, Wang GR, Diffey WF, Ashley P, Sundaram S (2009b) Numerical analysis of electrokinetic transport in micro-nanofluidic interconnect preconcentrator in hydrodynamic flow. Microfluid Nanofluid 7:683–696

    Article  Google Scholar 

  • Ward N, Mu X, Serrano G, Covington E, Kurdak C, Zellers ET, Mason AJ, Li W (2012) Microfluidic-packaged CMOS chemiresistor detector for micro-scale gas chromatograph. Micro Nano Lett 7:721–724

    Article  Google Scholar 

  • Weeks JD, Chandler D, Andersen HC (1971) Role of repulsive forces in determining the equilibrium structure of simple liquids. J Chem Phys 54(12):5237–5247

    Article  Google Scholar 

  • Wei GW (2010) Differential geometry based multiscale models. Bull Math Biol 72:1562–1622

    Article  MathSciNet  MATH  Google Scholar 

  • Wei G-W (2013) Multiscale, multiphysics and multidomain models I: basic theory. J Theor Comput Chem 12(8):1341006

    Article  Google Scholar 

  • Wei G-W, Zheng Q, Chen Z, Xia K (2012) Variational multiscale models for charge transport. SIAM Rev 54(4):699–754

    Article  MathSciNet  MATH  Google Scholar 

  • Weigl BH, Yager P (1997) Silicon-microfabricated diffusion-based optical chemical sensor. Sens Actuators B-Chem 39:452–457

    Article  Google Scholar 

  • Wu DP, Steckl AJ (2009) High speed nanofluidic protein accumulator. Lab Chip 9:1890–1896

    Article  Google Scholar 

  • Xia KL, Opron K, Wei GW (2013) Multiscale multiphysics and multidomain models—flexibility and rigidity. J Chem Phys 139:194109

    Article  Google Scholar 

  • Xia KL, Feng X, Tong YY, Wei GW (2014) Multiscale geometric modeling of macromolecules. J Comput Phys 275:912–936

    Article  MathSciNet  Google Scholar 

  • Yan RX, Liang WJ, Fan R, Yang PD (2009) Nanofluidic diodes based on nanotube heterojunctions. Nano Lett 9:3820–3825

    Article  Google Scholar 

  • Yu S, Wei GW (2007) Three-dimensional matched interface and boundary (mib) method for treating geometric singularities. J Comput Phys 227(1):602–632

    Article  MathSciNet  MATH  Google Scholar 

  • Yuan Z, Garcia AL, Lopez GP, Petsev DN (2007) Electrokinetic transport and separations in fluidic nanochannels. Electrophoresis 28(4):595–610

    Article  Google Scholar 

  • Zheng Q, Wei GW (2011) Poisson–Boltzmann–Nernst–Planck model. J Chem Phys 134:194101

    Article  Google Scholar 

  • Zheng Z, Hansford DJ, Conlisk AT (2003) Effect of multivalent ions on electroosmotic flow in micro- and nanochannels. Electrophoresis 24:3006–3017

    Article  Google Scholar 

  • Zheng Q, Chen D, Wei GW (2011) Second-order Poisson–Nernst–Planck solver for ion transport. J Comput Phys 230:5239–5262

    Article  MathSciNet  MATH  Google Scholar 

  • Zhou YC, Lu BZ, Huber GA, Holst MJ, McCammon JA (2008) Continuum simulations of acetylcholine consumption by acetylcholinesterase: a Poisson–Nernst–Planck approach. J Phys Chem B 112:270–275

    Article  Google Scholar 

  • Zhou K, Perry JM, Jacobson SC (2011) Transport and sensing in nanofluidic devices. Annu Rev Anal Chem 4:321–341

    Article  Google Scholar 

Download references

Acknowledgments

This work was supported in part by NSF Grants IIS-1302285 and DMS-1160352, and NIH Grant R01GM-090208. The authors thank an anonymous reviewer for useful suggestions.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Guo-Wei Wei.

Appendix

Appendix

See Tables 5 and 6.

Table 5 Positions and charges of all atomic charges in the negatively charged channel
Table 6 Positions and charges of all atomic charges in the bipolar channel

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Park, J.K., Xia, K. & Wei, GW. Atomic scale design and three-dimensional simulation of ionic diffusive nanofluidic channels. Microfluid Nanofluid 19, 665–692 (2015). https://doi.org/10.1007/s10404-015-1593-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10404-015-1593-1

Keywords

Navigation