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A nanometre-scale resolution interference-based probe of interfacial phenomena between microscopic objects and surfaces.

Contreras-Naranjo JC, Ugaz VM - Nat Commun (2013)

Bottom Line: Interferometric techniques have proven useful to infer proximity and local surface profiles of microscopic objects near surfaces.But a critical trade-off emerges between accuracy and mathematical complexity when these methods are applied outside the vicinity of closest approach.The unique view-from-below perspective of reflection interference contrast microscopy also reveals previously unseen deformations and allows the first direct observation of femtolitre-scale capillary condensation dynamics underneath micron-sized particles.

View Article: PubMed Central - PubMed

Affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA.

ABSTRACT
Interferometric techniques have proven useful to infer proximity and local surface profiles of microscopic objects near surfaces. But a critical trade-off emerges between accuracy and mathematical complexity when these methods are applied outside the vicinity of closest approach. Here we introduce a significant advancement that enables reflection interference contrast microscopy to provide nearly instantaneous reconstruction of an arbitrary convex object's contour next to a bounding surface with nanometre resolution, making it possible to interrogate microparticle/surface interaction phenomena at radii of curvature 1,000 times smaller than those accessible by the conventional surface force apparatus. The unique view-from-below perspective of reflection interference contrast microscopy also reveals previously unseen deformations and allows the first direct observation of femtolitre-scale capillary condensation dynamics underneath micron-sized particles. Our implementation of reflection interference contrast microscopy provides a generally applicable nanometre-scale resolution tool that can be potentially exploited to dynamically probe ensembles of objects near surfaces so that statistical/probabilistic behaviour can be realistically captured.

No MeSH data available.


Related in: MedlinePlus

Near-instantaneous surface profile reconstruction.Detailed surface profile reconstruction of a glass bead in air (a) and polymer vesicles in buffer solution hovering next to the substrate (b) and in contact with the substrate (c); insets present the corresponding RICM images (scale bar, 10 μm), schematic representations of the system and ΔSP/Δx versus x from a simulated non-planar fit (black exes) to experimental data (light red symbols/line, without/with smoothing). Four different procedures (listed in increasing order of accuracy) are used to reconstruct the bottom shape of these specimens: discrete planar (gray dots) and non-planar (dashed green line) methods, continuous ODE (closed/open red circles, NRL/non-NRL) approach and non-planar fit (thin black line). A sphere profile (thick orange line) is fitted to selected reconstructed heights from the ODE method and the non-planar fit is used to define the expected surface profile so that the error of the other procedures can be quantified (d). (e) A three-dimensional reconstruction of the bottom shape of a non-symmetric polymer vesicle hovering next to the substrate (~37 nm) as observed from three different points of view approximately located at M, N and O in the RICM image, with the corresponding bottom view also shown; heights in the colour bar and positions are given in microns, scale bar, 10 μm in the RICM image.
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f6: Near-instantaneous surface profile reconstruction.Detailed surface profile reconstruction of a glass bead in air (a) and polymer vesicles in buffer solution hovering next to the substrate (b) and in contact with the substrate (c); insets present the corresponding RICM images (scale bar, 10 μm), schematic representations of the system and ΔSP/Δx versus x from a simulated non-planar fit (black exes) to experimental data (light red symbols/line, without/with smoothing). Four different procedures (listed in increasing order of accuracy) are used to reconstruct the bottom shape of these specimens: discrete planar (gray dots) and non-planar (dashed green line) methods, continuous ODE (closed/open red circles, NRL/non-NRL) approach and non-planar fit (thin black line). A sphere profile (thick orange line) is fitted to selected reconstructed heights from the ODE method and the non-planar fit is used to define the expected surface profile so that the error of the other procedures can be quantified (d). (e) A three-dimensional reconstruction of the bottom shape of a non-symmetric polymer vesicle hovering next to the substrate (~37 nm) as observed from three different points of view approximately located at M, N and O in the RICM image, with the corresponding bottom view also shown; heights in the colour bar and positions are given in microns, scale bar, 10 μm in the RICM image.

Mentions: We validated our simplified reconstruction approach using experimentally obtained interferograms from the RICM analysis of a glass bead in air and polymer vesicles in aqueous medium, which are in close proximity to a glass substrate (Fig. 6; INA=0.48 and numerical aperture=1.25). The optical path in the glass bead system is composed of glass/air/glass media with refractive indices of 1.53/1/1.51, respectively. The polymer vesicle systems involve glass/buffer/polymer membrane (15-nm thickness35)/sucrose solution with refractive indices of 1.53/1.334/1.51/1.351, respectively.


A nanometre-scale resolution interference-based probe of interfacial phenomena between microscopic objects and surfaces.

Contreras-Naranjo JC, Ugaz VM - Nat Commun (2013)

Near-instantaneous surface profile reconstruction.Detailed surface profile reconstruction of a glass bead in air (a) and polymer vesicles in buffer solution hovering next to the substrate (b) and in contact with the substrate (c); insets present the corresponding RICM images (scale bar, 10 μm), schematic representations of the system and ΔSP/Δx versus x from a simulated non-planar fit (black exes) to experimental data (light red symbols/line, without/with smoothing). Four different procedures (listed in increasing order of accuracy) are used to reconstruct the bottom shape of these specimens: discrete planar (gray dots) and non-planar (dashed green line) methods, continuous ODE (closed/open red circles, NRL/non-NRL) approach and non-planar fit (thin black line). A sphere profile (thick orange line) is fitted to selected reconstructed heights from the ODE method and the non-planar fit is used to define the expected surface profile so that the error of the other procedures can be quantified (d). (e) A three-dimensional reconstruction of the bottom shape of a non-symmetric polymer vesicle hovering next to the substrate (~37 nm) as observed from three different points of view approximately located at M, N and O in the RICM image, with the corresponding bottom view also shown; heights in the colour bar and positions are given in microns, scale bar, 10 μm in the RICM image.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675327&req=5

f6: Near-instantaneous surface profile reconstruction.Detailed surface profile reconstruction of a glass bead in air (a) and polymer vesicles in buffer solution hovering next to the substrate (b) and in contact with the substrate (c); insets present the corresponding RICM images (scale bar, 10 μm), schematic representations of the system and ΔSP/Δx versus x from a simulated non-planar fit (black exes) to experimental data (light red symbols/line, without/with smoothing). Four different procedures (listed in increasing order of accuracy) are used to reconstruct the bottom shape of these specimens: discrete planar (gray dots) and non-planar (dashed green line) methods, continuous ODE (closed/open red circles, NRL/non-NRL) approach and non-planar fit (thin black line). A sphere profile (thick orange line) is fitted to selected reconstructed heights from the ODE method and the non-planar fit is used to define the expected surface profile so that the error of the other procedures can be quantified (d). (e) A three-dimensional reconstruction of the bottom shape of a non-symmetric polymer vesicle hovering next to the substrate (~37 nm) as observed from three different points of view approximately located at M, N and O in the RICM image, with the corresponding bottom view also shown; heights in the colour bar and positions are given in microns, scale bar, 10 μm in the RICM image.
Mentions: We validated our simplified reconstruction approach using experimentally obtained interferograms from the RICM analysis of a glass bead in air and polymer vesicles in aqueous medium, which are in close proximity to a glass substrate (Fig. 6; INA=0.48 and numerical aperture=1.25). The optical path in the glass bead system is composed of glass/air/glass media with refractive indices of 1.53/1/1.51, respectively. The polymer vesicle systems involve glass/buffer/polymer membrane (15-nm thickness35)/sucrose solution with refractive indices of 1.53/1.334/1.51/1.351, respectively.

Bottom Line: Interferometric techniques have proven useful to infer proximity and local surface profiles of microscopic objects near surfaces.But a critical trade-off emerges between accuracy and mathematical complexity when these methods are applied outside the vicinity of closest approach.The unique view-from-below perspective of reflection interference contrast microscopy also reveals previously unseen deformations and allows the first direct observation of femtolitre-scale capillary condensation dynamics underneath micron-sized particles.

View Article: PubMed Central - PubMed

Affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA.

ABSTRACT
Interferometric techniques have proven useful to infer proximity and local surface profiles of microscopic objects near surfaces. But a critical trade-off emerges between accuracy and mathematical complexity when these methods are applied outside the vicinity of closest approach. Here we introduce a significant advancement that enables reflection interference contrast microscopy to provide nearly instantaneous reconstruction of an arbitrary convex object's contour next to a bounding surface with nanometre resolution, making it possible to interrogate microparticle/surface interaction phenomena at radii of curvature 1,000 times smaller than those accessible by the conventional surface force apparatus. The unique view-from-below perspective of reflection interference contrast microscopy also reveals previously unseen deformations and allows the first direct observation of femtolitre-scale capillary condensation dynamics underneath micron-sized particles. Our implementation of reflection interference contrast microscopy provides a generally applicable nanometre-scale resolution tool that can be potentially exploited to dynamically probe ensembles of objects near surfaces so that statistical/probabilistic behaviour can be realistically captured.

No MeSH data available.


Related in: MedlinePlus