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Dr. Virginia M. Ayres
The Electronic and Biological Nanostructures Laboratory
Research - Scanning Probe Recognition Microscopy/Nanobiology

SCANNING PROBE RECOGNITION MICROSCOPY

Scanning Probe Recognition Microscopy (SPRM) is a new scanning probe microscopy capability developed with myself as Principal Investigator in an NSF GOALI collaborative partnership with Veeco Instruments. In Scanning Probe Recognition Microscopy, the scanning probe microscope system itself is given the power auto-track specific regions of interest through feature recognition coupled with adaptive scan plan generation and implementation. 'Feature' means any recognizable element, not just topography; for example, I currently investigate nanoscale elasticity as a physical property feature. SPRM is an approach that works directly with the interaction sensing capability of a scanning probe microscope, which inherently has atomic to nanometer scale resolution. The human operator interaction is now focused to the decision-making level rather than the execution level, and the research emphasis evolves from sample imaging to feature/property investigation.



Scanning Probe Recognition Microscopy in Regenerative Medicine

In the images shown below, SPRM is used to auto-track along individual nanofibers within a nanofibrillar matrix of electrospun polyamide nanofibers, enabling property extraction including nanoscale elasticity and surface roughness. Data from SPRM auto-track investigations over multiple individual nanofibers is compiled into a new, statistical representation of each property for the nanofibrillar matrix as a whole. These particular nanofibrillar matrices are used as tissue scaffolds for regenerative medicine for the central nervous system (brain and spinal cord), which is one of the most challenging injury repair situations.


Figure 1. SPRM auto-tracking along individual nanofibers within a tissue scaffold. (Ayres, V, et al, Int. J. Nanomanufacturing, in press, 2009)

AFM SPRM
AFM image of a fiber mat showing a selected area from which the right image was taken.
Scanning Probe Recognition Microscopy image showing two fibers that the probe found and the scanner followed. Vertical scale colors for the SPRM image.
A coarse scan encountered the left hand nanofiber. A high resolution scan was initiated and performed to the end of the scan range. The tip was then returned to where coarse scan mode was interrupted and continued until it encountered the right hand nanofiber. See as SPRM video (.avi).

Figure 2. SPRM nanofiber auto-tracking improved by adaptive learning. (Ayres, V, et al, Int. J. Nanomanufacturing, in press, 2009)

AFM SPRM
AFM image of a fiber mat showing a selected area from which the right image was taken.
Scanning Probe Recognition Microscopy image showing a fiber that the probe followed across a crossover by another fiber. Vertical scale colors for the SPRM image.
Incorporation of adaptive learning in SPRM enables the high resolution scan along the nanofiber to continue past the cross-over point of two crossed fibers. See as SPRM video (.avi).


TBDFigure 3. SPRM statistical plot of nanofibrillar matrix elasticity. Neural cell interactions are directed by both biochemical cues and physcial cues, including nanoscale elasticity. SPRM invesitgation shows that the overall nanofibrillar matrix elasticity changes when the nanofibers are covalently modified with growth factor FGF-2, to mimic sequestration of growth factors on the extracellular matrix at the blood-brain barrier. (Ayres, V, et al, Int. J. Nanomanufacturing, in press, 2009)

TBDFigure 4. Unmodified versus covalently FGF-2 modified nanofibers. Survey AFM images of nanofibrillar scaffolds showing unmodified and covalently FGF-2 modified nanofibers. (AFM images: Ayres' EBNL group, MSU) (Delgado-Rivera, R, et al, Matrix Biology, 2009)

TBDFigure 5. Astrocytes on 2D versus 3D nanofibrillar substrates. Collaborative work with Dr. Sally Meiners at the University of Medicine and Dentistry of New Jersey (UMDNJ) is linking the nanoscale physical and biochemical cues of the prosthetic nanofibrillar scaffolds with important astrocyte and astrocyte-neuron responses. Significant differences in astrocyte response to 2D planar, 3D nanofibrillar and 3D nanofibrillar covalently modified with FGF-2 substrates are observed. The most in-vivo-like response is to 3D nanofibrillar covalently modified with FGF-2 substrates but even unmodified 3D nanofibrillar substrates improve life for astrocytes. (Optical images: Meiners' group, UMDNJ) (Delgado-Rivera, R, et al, Matrix Biology, 2009)


SPRM References

  1. (PDF) Ayres, VM, Chen, Q, Fan, Y, Flowers, DA, Meiners, S, Ahmed I, Delgado-Rivera R. Scanning probe recognition microscopy investigation of neural cell prosthetic properties. Internat J Nanomanufact, in press 2009.
  2. (PDF) Delgado-Rivera, R, Harris, SL, Ahmed, I, Babu, AN, Patel, R, Kamal, J, Ayres, V, Flowers, D, Meiners, S, 2009. Increased FGF-2 secretion and ability to support neurite outgrowth by astrocytes cultured on polyamide nanofibrillar matrices. Matrix Biology 28, 137-147.
  3. (PDF) Meiners, S, Ahmed, I, Ponery, AS, Amor, N, Ayres, VM, Fan, Y, Chen, Q, Babu, AN, 2007. Engineering Electrospun Nanofibrillar Surfaces for Spinal Cord Repair: A Discussion, Polymer Internat 56:1340-1348.Invited manuscript for In Focus issue.
  4. (PDF) Fan, Y, Chen, Q, Ayres, VM, Baczewski, AD, Udpa, L, Kumar, S, 2007. Scanning Probe Recognition Microscopy Investigation of Tissue Scaffold Properties, Int J Nanomedicine 2:651-661.
  5. (PDF) Chen, Q, Fan, Y, Udpa, L, Ayres, VM, 2007. Cell Classification by Moments Based Methods with Continuous Wavelet Transform, Int J Nanomedicine 2:181-189
  6. (PDF) Udpa, L, Ayres, VM, Fan, Y, Chen, Q, run-Kumar, S, 2006. Deconvolution of Atomic Force Microscopy Data for Cellular and Molecular Imaging. IEEE Sig. Proc Mag 23: 73-83. Invited manuscript for Special Issue on Molecular and Cellular Bioimaging
  7. (PDF) Rutledge, SL, Shaw, HC, Yowell, LL, Chen, Q, Jacobs, BW, Song, SP, and Ayres, VM, 2006. Self Assembly and Correlated Properties of Electrospun Carbon Nanofibers. Diamond and Relat Mater 15:1070-1074
  8. (PDF) Ayres, V., Udpa, L, 2006. Scanning Tunneling Microscopy, pp 516-523 in Encyclopedia of Medical Devices and Instrumentation (Second Edition). Editor Webster, J, John Wiley and Sons Inc, Hoboken, NJ. Invited review in medical reference encyclopedia.
  9. (PDF) Fan, Y, Chen, Q, Kumar, S, Baczewski, AD, Udpa, L, Ayres, VM, Rice, AF, 2007. Scanning Probe Recognition Microscopy Investigation of Nanoscale Mechanical and Surface Roughness Properties Along Nanofibers, pp 1021-HH05-26. In Surface and Interfacial Nanomechanics, Editors Cook, RF, Ducker,W, Szlufarska, I, R.F. Antrim,RF, Mater. Res. Soc. Symp. Proc. Volume 1021E, Warrendale, PA.
  10. (PDF) Chen, Q, Fan, Y, Kumar, S, Baczewski, AD, Udpa, L, Ayres, VM, Rice, AF, Meiners, S, Ahmed, I, 2007. Cell Response and Tissue Scaffold Triggers Investigated by Scanning Probe Recognition Microscopy, pp 1019-FF06-04. In Engineered Nanoscale Materials for the Diagnosis and Treatment of Disease, Editors Hackley, VA, Patri, AK, Stein, J, Moudgil, BM, Mater. Res. Soc. Symp. Proc. Volume 1019E, Warrendale, PA.
© Copyright 2011, Virginia M. Ayres