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Self-assembly and modular functionalization of three-dimensional crystals from oppositely charged proteins.

Liljeström V, Mikkilä J, Kostiainen MA - Nat Commun (2014)

Bottom Line: Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment.Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules.Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range.

View Article: PubMed Central - PubMed

Affiliation: 1] Biohybrid Materials Group, Department of Biotechnology and Chemical Technology, Aalto University, 00076 Aalto, Finland [2] Molecular Materials Group, Department of Applied Physics, Aalto University, 00076 Aalto, Finland.

ABSTRACT
Multicomponent crystals and nanoparticle superlattices are a powerful approach to integrate different materials into ordered nanostructures. Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment. Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules. We electrostatically assembled cowpea chlorotic mottle virus particles and avidin proteins into heterogeneous crystals, where the virus particles adopt a non-close-packed body-centred cubic arrangement held together by avidin. Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range. Furthermore, the use of avidin-biotin interaction allows highly selective pre- or post-functionalization of the protein crystals in a modular way with different types of functional units, such as fluorescent dyes, enzymes and plasmonic nanoparticles.

No MeSH data available.


Related in: MedlinePlus

Functionalization with AuNPs.Biotinylated gold nanoparticles (B-AuNPs) with a gold core diameter of ~5 nm (a) can be incorporated to crystals according to the measured SAXS curves. Form factor P(q) of the AuNPs dominates the scattering pattern indicating heterogeneous distribution of AuNPs in the crystal (b), which can also be visualized with TEM (c). Scale bar, 150 nm. (d) An AuNP cluster in the absence of protein crystals compared with a magnified view of the AuNP-functionalized crystals. Dimensions for the images are 150 × 150 nm. A comparison to a previously obtained AB8fcc-type CCMV–AuNP binary crystals viewed along the [110] projection axis (e). Here the AuNPs occupy defined lattice points. (f) Fourier transform from image e and inverse Fourier transform calculated with selected Fourier components.
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f8: Functionalization with AuNPs.Biotinylated gold nanoparticles (B-AuNPs) with a gold core diameter of ~5 nm (a) can be incorporated to crystals according to the measured SAXS curves. Form factor P(q) of the AuNPs dominates the scattering pattern indicating heterogeneous distribution of AuNPs in the crystal (b), which can also be visualized with TEM (c). Scale bar, 150 nm. (d) An AuNP cluster in the absence of protein crystals compared with a magnified view of the AuNP-functionalized crystals. Dimensions for the images are 150 × 150 nm. A comparison to a previously obtained AB8fcc-type CCMV–AuNP binary crystals viewed along the [110] projection axis (e). Here the AuNPs occupy defined lattice points. (f) Fourier transform from image e and inverse Fourier transform calculated with selected Fourier components.

Mentions: To investigate the incorporation of plasmonic nanoparticles into the protein crystals, biotin-tagged AuNPs (B-AuNPs) with a metal core diameter of ~5 nm were used (Fig. 8a). Scattering curves obtained from B-AuNP pre-functionalized crystals shows clearly the presence of bcc lattice and B-AuNP form factor P(q), which dominates the scattering due to the high electron density of gold. Taking the B-AuNPP(q) into account, the measured scattering curve is in excellent agreement with the scattering patterns from non-functionalized samples and comparable to crystals functionalized with B-HRP or BF (Supplementary Fig. 7). However, the Bragg reflections are not enhanced, which implies that the B-AuNPs are heterogeneously distributed in the crystals (Fig. 8b). TEM images of AuNP-functionalized crystals further support heterogeneous distribution and show that the AuNPs are well-dispersed throughout the CCMV–avidin crystal and do not occupy defined lattice points (Fig. 8c). Also the observed redshift in the absorption maximum for gold particles indicates that they are in close proximity (Supplementary Fig. 8 and Supplementary Note 3). Yet, the organization of the particles is clearly directed by the crystal and tightly clustered particles are absent. TEM images comparing clustered and crystal-dispersed AuNPs reveal a clear difference (Fig. 8d). In comparison, we have previously shown that cationic AuNPs can electrostatically self-assemble with CCMV particles to produce AB8fcc -type binary superlattices, where the AuNPs occupy the octahedral voids of close-packed CCMV-lattice with an fcc structure20. TEM image viewing such a lattice along the [110] projection axis is shown in Fig. 8e. Image Fourier transform and inverse Fourier transform calculated with selected Fourier components indicate high degree of order (Fig. 8f).


Self-assembly and modular functionalization of three-dimensional crystals from oppositely charged proteins.

Liljeström V, Mikkilä J, Kostiainen MA - Nat Commun (2014)

Functionalization with AuNPs.Biotinylated gold nanoparticles (B-AuNPs) with a gold core diameter of ~5 nm (a) can be incorporated to crystals according to the measured SAXS curves. Form factor P(q) of the AuNPs dominates the scattering pattern indicating heterogeneous distribution of AuNPs in the crystal (b), which can also be visualized with TEM (c). Scale bar, 150 nm. (d) An AuNP cluster in the absence of protein crystals compared with a magnified view of the AuNP-functionalized crystals. Dimensions for the images are 150 × 150 nm. A comparison to a previously obtained AB8fcc-type CCMV–AuNP binary crystals viewed along the [110] projection axis (e). Here the AuNPs occupy defined lattice points. (f) Fourier transform from image e and inverse Fourier transform calculated with selected Fourier components.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109007&req=5

f8: Functionalization with AuNPs.Biotinylated gold nanoparticles (B-AuNPs) with a gold core diameter of ~5 nm (a) can be incorporated to crystals according to the measured SAXS curves. Form factor P(q) of the AuNPs dominates the scattering pattern indicating heterogeneous distribution of AuNPs in the crystal (b), which can also be visualized with TEM (c). Scale bar, 150 nm. (d) An AuNP cluster in the absence of protein crystals compared with a magnified view of the AuNP-functionalized crystals. Dimensions for the images are 150 × 150 nm. A comparison to a previously obtained AB8fcc-type CCMV–AuNP binary crystals viewed along the [110] projection axis (e). Here the AuNPs occupy defined lattice points. (f) Fourier transform from image e and inverse Fourier transform calculated with selected Fourier components.
Mentions: To investigate the incorporation of plasmonic nanoparticles into the protein crystals, biotin-tagged AuNPs (B-AuNPs) with a metal core diameter of ~5 nm were used (Fig. 8a). Scattering curves obtained from B-AuNP pre-functionalized crystals shows clearly the presence of bcc lattice and B-AuNP form factor P(q), which dominates the scattering due to the high electron density of gold. Taking the B-AuNPP(q) into account, the measured scattering curve is in excellent agreement with the scattering patterns from non-functionalized samples and comparable to crystals functionalized with B-HRP or BF (Supplementary Fig. 7). However, the Bragg reflections are not enhanced, which implies that the B-AuNPs are heterogeneously distributed in the crystals (Fig. 8b). TEM images of AuNP-functionalized crystals further support heterogeneous distribution and show that the AuNPs are well-dispersed throughout the CCMV–avidin crystal and do not occupy defined lattice points (Fig. 8c). Also the observed redshift in the absorption maximum for gold particles indicates that they are in close proximity (Supplementary Fig. 8 and Supplementary Note 3). Yet, the organization of the particles is clearly directed by the crystal and tightly clustered particles are absent. TEM images comparing clustered and crystal-dispersed AuNPs reveal a clear difference (Fig. 8d). In comparison, we have previously shown that cationic AuNPs can electrostatically self-assemble with CCMV particles to produce AB8fcc -type binary superlattices, where the AuNPs occupy the octahedral voids of close-packed CCMV-lattice with an fcc structure20. TEM image viewing such a lattice along the [110] projection axis is shown in Fig. 8e. Image Fourier transform and inverse Fourier transform calculated with selected Fourier components indicate high degree of order (Fig. 8f).

Bottom Line: Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment.Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules.Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range.

View Article: PubMed Central - PubMed

Affiliation: 1] Biohybrid Materials Group, Department of Biotechnology and Chemical Technology, Aalto University, 00076 Aalto, Finland [2] Molecular Materials Group, Department of Applied Physics, Aalto University, 00076 Aalto, Finland.

ABSTRACT
Multicomponent crystals and nanoparticle superlattices are a powerful approach to integrate different materials into ordered nanostructures. Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment. Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules. We electrostatically assembled cowpea chlorotic mottle virus particles and avidin proteins into heterogeneous crystals, where the virus particles adopt a non-close-packed body-centred cubic arrangement held together by avidin. Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range. Furthermore, the use of avidin-biotin interaction allows highly selective pre- or post-functionalization of the protein crystals in a modular way with different types of functional units, such as fluorescent dyes, enzymes and plasmonic nanoparticles.

No MeSH data available.


Related in: MedlinePlus