10 research outputs found
Optical Measurement of Neural Activity Using Surface Plasmon Resonance
We demonstrate that surface plasmon resonance (SPR) is applicable to the optical detection of neural signals.
A low-noise SPR sensor was developed as a label- and artifact-free method for the extracellular recording
of neural activity. The optical responses obtained from a rat sciatic nerve were highly correlated with
simultaneously recorded electrical responses. Additional studies with stimulation intensity and lidocaine
further confirmed that the optically measured signals originated from neural activities.The authors acknowledge the support of the Nano-
Bioelectronics and Systems Research Center of Seoul
National University, which is an Engineering Research
Center sponsored by the Korean Science and
Engineering Foundation (R11-2000-075-01001-1).
The authors also thank Hyung Chul Shin and Woo
Taek Oh for their helpful advice and Inter-university
Semiconductor Research Center for providing a laboratory
space
The topographical guidance of neurons cultured on holographic photo-responsive polymer
Neuronal cells to respond to submicron-scale groove structure. On the grooved structure of particular dimension, it has been reported that neuronal cells grew perpendicular to the groove direction. We used holographic photo-responsive polymer to form a submicron-scale surface relief grating structure. A sinusoidal groove pattern is built up by holographic interference of 488 nm Ar ion laser beams. The primary hippocampal neurons cultured on the surface of the polymer film grew extending their neurites in a perpendicular orientation to the groove direction. This suggests that laser holography can be used to control the neurites orientation and growth. The holographic grating and photo-responsive polymer will raise the possibility of controlling neural network formation between living cells by light.This work was supported by Korea Science and
Engineering Foundation (KOSEF) through Nano
Bioelectronics and Systems Research Center (NBS-ERC) in
Seoul National University
Antibody-Based Surface Plasmon Resonance Detection of Intact Viral Pathogen
Surface plasmon resonance (SPR) technique
was used to directly detect an intact form of insect
pathogen: the baculovirus, Autographa californica multiple
nuclear polyhedrosis virus (AcMNPV). An SPR sensor
chip with three bio-functional layerswasusedto detect the
intact AcMNPV: amine-reactive crosslinker with a disulfide
bond that chemisorbs to gold film, Protein A, and a
mouse IgG monoclonal antibody raised against a surface
protein of the target viral pathogen. A two-channel
(reference & test) micro-fluidic SPR system is used
for reliable measurement. Bio-specific response to the
AcMNPV is compared with the response for tobacco
mosaic virus (TMV) as control. Successive exposure of the
sensor chip to both viruses verifies a specific response to
AcMNPV. This serves as a prerequisite to the development
of a new type of viral pathogen detection sensors.The authors are grateful to Dr. Mandy Esch (Cornell Nanoscale
Facility, Cornell University) for valuable advice on fabrication and
surface chemistry, Dr. Gary Blissard (Boyce Thompson Institute,
Cornell University) for kindly providing AcMNPV baculovirus and
AcV1 monoclonal antibody producing hybridoma cell line, and Dr.
Milton Zaitlin (Department of Plant Pathology, Cornell University) for kindly providing tobacco mosaic virus. This work was partly supported
by DARPA through CBOM, and also partly by joint research program
of Cornell Biomedical Engineering Program and Nano Bioelectronics
and Systems Research Center of Seoul National University through
KOSEF. M.L.S. acknowledges support as a NYSTAR Distinguished
Professor through the New York State Office of Science, Technology
and Academic Research
GUIDING NEURONS AND FIBROBLAST CELLS USING MICROFIBRICATION ON PHOTOPOLYMER FOR IN-SITU NAVIGATON OF CELLULAR PATTERNING
Cellular patterning has diverse and
potential applications in scientific research and
engineering. We used laser holographic fabrication
to construct the cellular patterning. By the
interference of two laser beam on the polymer micro
and nanoscale grooves were generated on the
photoresponsive polymer. The growth of rat
hippocampal neurons were controlled with the
microfabricated structure. The directions of neurites
were predominant in the perpendicular direction of
the grooves and the growth rates of the neurites were
also stimulated. Two dimensional cellular patterning
of fibroblast cells was constructed along the
patterned microstructures on the polymer. These
results indicate the feasibility of guiding neurons and
fibroblast cells with laser holography, opening the
possibility for in-situ navigation in living cells
Extracellular Optical Recording Configuration for Neuronal Action Potential Detection by using Surface Plasmon Resonance: Preliminary Experiment
We propose an extracellular optical recording configuration for neuronal action potential detection by using surface plasmon resonance (SPR). The method does not use fluorescence dyes but still taking advantages of optical recording. As a preliminary experiment, the electrochemical SPR effect without neurons was investigated. This showed that a high resolution SPR setup (10-4~10~5 angular shift or more) is required to overcome noise and improve SPR signal. Several issues for neural signal recording are addressed to modify SPR optical configuration.This work was supported by Korea Science and Engineering Foundation (KOSEF) through Nano Bioelectronics and Systems Research Center (NBS-ERC) in Seoul National University, Nanobiotechnology Center (NBTC), an STC Program of the National Science Foundation (Agreement No. ECS-9876771), and the Cornell Nanoscale Facility (Agreement No. ECS-9731293)
Submicron-scale topographical control of cell growth using holographic surface relief grating
The cell orientation and attachment were controlled by a submicron-scale topographical cue. For achieving the submicron undulation of
surface topography, the laser holography on a photo-responsive azobenzene copolymer layer has been employed to produce surface relief
grating (SRG) which has a regular sinusoidal shape. Cultured human astrocytes (HA) were preferentially attached onto the SRG surface and
highly elongated along the SRG direction. This topographical control scheme would be very efficient to control the cell growth for cellular
engineering applications and to understand the interactions of the cells with a submicron-scale topographical surface.This work was supported partly by Overhead Research
Fund of S.N.U. and also partly by KOSEF through the
Nano-Bioelectronics and Systems Research Center at Seoul
National University. One of the authors (SDL) acknowledges
the support from KOSEF through CFRM at Korea
University
Neural Prosthesis in the Wake of Nanotechnology : Controlled Growth of Neurons Using Surface Nanostructures
Neural prosthesis has been successfully applied to patients with motional
or sensory disabilities for clinical purpose. To enhance the performance
of the neural prosthetic device, the electrodes for the biosignal
recording or electrical stimulation should be located in closer proximity
to target neurons than they are now. Instead of revising the prior implanting
surgery to improve the electrical contact of neurons, we propose a
technique that can bring the neurons closer to the electrode sites. A new
method is investigated that can control the direction of neural cell
growth using surface nanostructures. We successfully guide the neurons
to the position of the microelectrodes by providing a surface topographical
cue presented by the surface nanostructure on a photoresponsive
polymer material. Because the surface structure formed by laser holography
is reversible and repeatable, the geometrical positioning of the
neurons to microelectrodes can be adjusted by applying laser treatment
during the surgery for the purpose of improving the performance of
neural prosthetic device
A new image signal transfer method using laser in artificial retina
A new optical link method for the retinal prosthesis is proposed. A laser diode system was chosen to transfer image into the eye and the new optical system was designed and evaluated in silico and ex vivo. The use of laser diode array in artificial retina system makes system simple by deleting signal processing part inside of the eyeball. The designed optical system is enough to focus laser beam on photodiode array in 20 ร 20 application on simulation using Code V program, and about 200 ฮผm focusing of laser beam was possible on experiment with porcine eye.This paper was supported by the Nano Bioelectronics and
Systems Research Center of Seoul National University,
which is an ERC supported by the Korean Science and
Engineering Foundation (KOSEF)
Soft Bio-Integrated Multifunctional Devices Using an Intrinsically Stretchable Conducting Nanomembrane
Soft bioelectronic systems with a unique mechanical property, namely modulus matching between human skin (or tissue) and the device, have gained widespread attention. This is because of their closed-loop strain-insensitive electrical performance ranging from application in the long-term stable measurements of physiological signals and feedback modulation to human skin (or organs). Various materials and integration/fabrication strategies such as buckled, rigid islands, and wavy designs addressed for soft bioelectronic systems require complex device fabrication with time-consuming packaging and integration processes. In this study, we developed a soft bio-integrated multifunctional device (SBMD) fabricated through the simple thermal evaporation and transfer processes. The intrinsically stretchable AuโSEBS film composed of thermally evaporated gold (Au) nanomembranes and an elastomeric substrate was applied to various functional modules that are capable of sensing the strain (up to ~300%), temperature (with a thermal sensitivity of ~0.6 ฮฉ/ยฐC), chemicals (at a concentration of NaCl of ~0.5 wt%), and even electrophysiological cardiac/muscle signals and showing thermal actuations (80 ยฐC at 9 V). Specifically, such multifunctions of the SBMD were stably performed even on skin. Thus, we believe the SBMD would be a promising candidate for realizing soft bioelectronic systems