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Neurotransmitter Specific, Cellular-Resolution Functional Brain Mapping Using Receptor Coated Nanoparticles: Assessment of the Possibility.

Forati E, Sabouni A, Ray S, Head B, Schoen C, Sievenpiper D - PLoS ONE (2015)

Bottom Line: Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine.The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported.The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach.

View Article: PubMed Central - PubMed

Affiliation: Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA 92098, United States of America.

ABSTRACT
Receptor coated resonant nanoparticles and quantum dots are proposed to provide a cellular-level resolution image of neural activities inside the brain. The functionalized nanoparticles and quantum dots in this approach will selectively bind to different neurotransmitters in the extra-synaptic regions of neurons. This allows us to detect neural activities in real time by monitoring the nanoparticles and quantum dots optically. Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine. The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported. The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach.

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Related in: MedlinePlus

The standard results set for NR3 using Antidop as the receptor and Dop as the neurotransmitter.The numbers in parenthesizes report the peak wavelengths of each curve in units of nm.
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pone.0145852.g005: The standard results set for NR3 using Antidop as the receptor and Dop as the neurotransmitter.The numbers in parenthesizes report the peak wavelengths of each curve in units of nm.

Mentions: After repeating the same experiments with smaller nanospheres than 80nm, we concluded that the shifts are too small to be detectable. The redshift in nanospheres with sizes larger than 80nm were repeatable and therefore proved the proposed concept. However, the sensitivity was still too small (2nm for NS6) to be useful in practical instrument designs. Besides increasing their surface area, the sensitivity of GNPs to neurotransmitters can be enhanced by choosing GNPs with higher resonance quality factor which in turn increases the localized electric fields intensities on the GNPs’ surface. Fig 5 reveals the standard results set for NR3 using Antidop and Dop as the receptor and the neurotransmitter, respectively. A redshift of 10nm post binding of Dop to the functionalized nanorod was observable in the second absorption peak in Fig 5. The enhanced shift in the spectrum of the nanorod compared to nanospheres is due to its higher resonance quality factor which in turn leads to a higher localized electric field based on Eq (1). Equivalently, by forming and solving an electromagnetic scattering problem, it is straight forward to show that prolate spheroids (which can be approximated by nanorods) have higher absorption cross section than spheres and oblate spheroids [34]. In fact, in the extreme limits of a spheroid, the absorption cross section of a lossy needle is several orders of magnitude larger than that of a disk (see Fig 2 in [34] which applied to any lossy spheroid on a different scale). Higher light absorption means stronger interaction with light, larger localized electric fields around the particle, and higher sensitivity to the environment.


Neurotransmitter Specific, Cellular-Resolution Functional Brain Mapping Using Receptor Coated Nanoparticles: Assessment of the Possibility.

Forati E, Sabouni A, Ray S, Head B, Schoen C, Sievenpiper D - PLoS ONE (2015)

The standard results set for NR3 using Antidop as the receptor and Dop as the neurotransmitter.The numbers in parenthesizes report the peak wavelengths of each curve in units of nm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4696845&req=5

pone.0145852.g005: The standard results set for NR3 using Antidop as the receptor and Dop as the neurotransmitter.The numbers in parenthesizes report the peak wavelengths of each curve in units of nm.
Mentions: After repeating the same experiments with smaller nanospheres than 80nm, we concluded that the shifts are too small to be detectable. The redshift in nanospheres with sizes larger than 80nm were repeatable and therefore proved the proposed concept. However, the sensitivity was still too small (2nm for NS6) to be useful in practical instrument designs. Besides increasing their surface area, the sensitivity of GNPs to neurotransmitters can be enhanced by choosing GNPs with higher resonance quality factor which in turn increases the localized electric fields intensities on the GNPs’ surface. Fig 5 reveals the standard results set for NR3 using Antidop and Dop as the receptor and the neurotransmitter, respectively. A redshift of 10nm post binding of Dop to the functionalized nanorod was observable in the second absorption peak in Fig 5. The enhanced shift in the spectrum of the nanorod compared to nanospheres is due to its higher resonance quality factor which in turn leads to a higher localized electric field based on Eq (1). Equivalently, by forming and solving an electromagnetic scattering problem, it is straight forward to show that prolate spheroids (which can be approximated by nanorods) have higher absorption cross section than spheres and oblate spheroids [34]. In fact, in the extreme limits of a spheroid, the absorption cross section of a lossy needle is several orders of magnitude larger than that of a disk (see Fig 2 in [34] which applied to any lossy spheroid on a different scale). Higher light absorption means stronger interaction with light, larger localized electric fields around the particle, and higher sensitivity to the environment.

Bottom Line: Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine.The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported.The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach.

View Article: PubMed Central - PubMed

Affiliation: Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA 92098, United States of America.

ABSTRACT
Receptor coated resonant nanoparticles and quantum dots are proposed to provide a cellular-level resolution image of neural activities inside the brain. The functionalized nanoparticles and quantum dots in this approach will selectively bind to different neurotransmitters in the extra-synaptic regions of neurons. This allows us to detect neural activities in real time by monitoring the nanoparticles and quantum dots optically. Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine. The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported. The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach.

Show MeSH
Related in: MedlinePlus