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NanointheBrain:Nano-NeuroscienceAschemicalcommunicationandkeybiomolecularinteractionsinthebrainoccuratthenanoscale,theideaofexploitingadvancesinnanosciencetostudybrainstructureandfunctionhasbeengainingincreasingattention.
Atthespring2009ACSmeeting,weorganizedasymposiumontheintersectionoftheseelds,sponsoredbytheKavliFoundation.
1Lastyear,theAllen,Gatsby,andKavliFoundationsbroughttogetherscientiststoidentifyopportunitiesinworkingacrosstheeldsofnanoscienceandneuroscience.
Planningofsubstantiallygreatereortsareunderway.
Oneoftheexcitingtopicsunderdiscussionistheideaofmappingthebraininitsentiretysoastounderstanditsfunction,andsometimesdysfunction.
Thisisadauntingtaskgiventhatthereare85billionneurons2andestimatedtobe100trillionsynapsesinthehumanbrain.
Currently,threecomplementaryapproachesareunderconsideration.
Inone,snap-shotsofconnectionsinthebrainareobtainedbymakingthinphysicalslicesandstackingelectronmicroscopyimagesoftheseslices.
Missingfromthesedatawillbedynamicandchemicalinformation.
Botharebelievedtounderlieplasticity,whichisthebasisoflearningandmemory,aswellasotherkeybrainfunctions.
Anotherapproachistotrytomakeadynamicvoltagemapofthebrain,essentiallydealingwiththebrainasifitwereacloserelativeofthecomputersweuseeveryday.
3Onepossibilityisthatemergentpropertiesunderlyinginformationuseandstor-agewillbecomeaccessiblebymap-pingnetworkactivityversussingleorsmallnumbersofmultipleunitrecord-ingscurrentlyavailable.
Athirdap-proachistotrytoobtainfunctionalchemicalmapsoftheca.
100notquiteorthogonalchemicalneurotransmittersystemsinthebrain.
Thegeneticandchemicalheterogeneityofthebrainandtheinteractionsbetweenvariousneurotransmittersystemsaremajortargetsforinvestigationbyneuroscientistsandthepharmaceuticalindustry;nanoscienceandnanotechnologyhavekeyrolestoplayintheseeorts.
Inallthreecases,thekeyscalesrangefromthecentimeterscaleinmappingbrainregionsandnetworks,tothemicrometerscaleofcellsandlocalconnectivity,tothe10nmscaleofsynapses,tothesingle-moleculescale.
Therearethustremendousopportunitiesatthisintersectionoftheeldsofnanoscienceandneuroscience.
Oneoftheexcitingtopicsunderdiscussionistheideaofmappingthebraininitsentiretysoastounderstanditsfunctionandsometimesdysfunction.
Atlargerscalesthanthoseconsideredhere,theconnectionsofbundlesofneuronsinthebraincanbemappedwithdiusiontensorimaging,aformofmagneticresonanceimaging.
4Shownherearereconstructedbertractsofthemid-sagittalplaneofthebrain.
Imagereproducedwithpermissionfromref4.
Copyright2006.
Publishedonline10.
1021/nn304724qEDITORIALManytechniquesarenowbeingdevelopedtotracksinglemoleculesdynamicallyathighspatialresolution.
5Inthisissue,anovelmethodofthree-dimensionaltrackingisdescribed.
6Yet,muchremainstobedoneevenindeterminingthefunctionoftheplethoraofmoleculesthatarefoundpredominantlyinthebrain.
Likewise,ourabilitytoperformneurochemicalandelectrophysiologicalmeasurementsneedstobeminiaturized,spedup,andmultiplexed.
Electricalmeasurementsattherelevanttimescales(milliseconds)arestraightforward,butgettingtothe10nmscaleandmakingthousands,tensofthousands,ormoremeasurementssimultaneouslyinvivoremainschallenging.
Obtainingdynamicchemicalmapsatthesescaleswillbeanevengreaterchallenge.
Ultimately,theinformationhandlingproblemsinacquisition,analysis,interpretation,andvisualizationwillalsoneedtobeaddressed.
Thereismuchtodo,andgrandchallengeslieahead.
Welookforwardtobringingyouthedevelop-mentsattheexcitingintersectionsofnanoscienceandneuroscienceonthesepagesandonthoseofoursisterjournals.
Thismonth,wewelcomeProf.
WarrenChan,CanadaResearchChairinBioNanotechnologyattheUniversityofTorontoInstituteofBiomaterialsandBiomedicalEngineeringasournewestassociateeditor.
Prof.
ChanisaleaderintheareaofdevelopingandapplyingnanosciencemethodstotrackthedynamicsofabnormalcellsandisafrequentcontributortoACSNano.
79Finally,wecongratulateRobertLefkowitzofDukeUniversityandBrianKobilkaonwinningthe2012NobelPrizeinChemistryfortheirworkonG-proteincoupledreceptors,10nanotransducersparticularlyimportantinneurotransmissioninthebrain.
AnneM.
AndrewsACSChemicalNeuroscience,AssociateEditorPaulS.
WeissEditor-in-ChiefREFERENCESANDNOTES1.
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;Weiss,P.
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NanoscienceattheSpring2009ACSNationalMeeting.
ACSNano2009,3,1.
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EqualNumbersofNeuronalandNonneuronalCellsMaketheHumanBrainanIsometricallyScaled-UpPrimateBrain.
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Comp.
Neurol.
2009,513,532–541.
3.
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;Roukes,M.
L;ChunYuste,R.
TheBrainActivityMapProjectandtheChallengeofFunctionalConnectomics.
Neuron2012,74,970–974.
4.
ImagefromThomasSchulzandWikimediacommons,http://commons.
wikimedia.
org/wiki/File:DTI-sagittal-bers.
jpg.
5.
Claridge,S.
A.
;Schwartz,J.
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;Weiss,P.
S.
Electrons,Photons,andForce:QuantitativeSingle-MoleculeMeasurementsfromPhysicstoBiology.
ACSNano2011,5,693–729.
6.
Han,J.
J.
;Kiss,C.
Bradbury,A.
R.
M.
;Werner,J.
H.
Time-Resolved,ConfocalSingle-MoleculeTrackingofIndividualOrganicDyesandFluorescentProteinsinThreeDimensions.
ACSNano2012,6,DOI:10.
1021/nn302912j.
7.
Albanese,A.
;Sykes,E.
A.
;Chan,W.
C.
W.
RougharoundtheEdges:TheInammatoryResponseofMicroglialCellstoSpikyNanoparticles.
ACSNano2010,4,2490–2493.
8.
Giri,S.
;Jennings,Sykes,E.
A.
;Jennings,T.
L.
;Chan,W.
C.
W.
RapidScreeningofGeneticBiomarkersofInfectiousAgentsUsingQuantumDotBarcodes.
ACSNano2011,5,1580–1587.
9.
Albanese,A.
;Chan,W.
C.
W.
EectofGoldNanoparticleAggregationonCellUptakeandToxicity.
ACSNano2011,5,5478–5489.
10.
http://www.
nobelprize.
org/nobel_prizes/chemistry/laureates/2012/.
ProfessorWarrenChanoftheUniversityofTorontojoinsACSNanoasanassociateeditor.
IMAGECOURTESYOFNATHANDENNETTE/CANADIANPRESSEDITORIAL