Abraham Wolcott Owen & Englund Research Group Department Of Chemistry, APAM and Electrical Engineering Columbia University.
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Abraham Wolcott Owen & Englund Research Group Department Of Chemistry, APAM and Electrical Engineering Columbia University Neuronal Activity Believed to Be “Emergent” And BAM Envisions This over a 15 year Plan Nanodiamond and Neurons at Columbia University/MIT What is used now to image neurons? Rafael Yuste- Nueuroscience Neuronal Staining and Action Potential Measurements Dirk Englund- Physics Fluorescent Center Physics (Nitrogen Vacancy Center) Jonathan Owen- Chemistry Nanocrystal Surface Science and Modification + + = State of the Art Neuronal Imaging Ca2+ Imaging Limitations: Direct Voltage Imaging : -Requires Suprathreshold Signals -Cellular Processes are faster than calcium dynamics -Suffers from saturation affects -Measure the potential of 100 mV over 5 nm= 2*105 V/cm2 - An E-field sensitive chromophore localization is critical -- Photodamage of cell membrane is issue - The Fluorescent Center in Diamond-The Nitrogen Vacancy Center Nitrogen Impurities next to carbon vacancy - States: NV+, NV0 and NV-NV-= Ground State Triplet - Tracking in cell for over 3 minutes Chang et al, Mass production and dynamic imaging with fluorescent nanodiamonds, Science, 2008 Hollenberg et al, Nature Nanotechnology, 2011, 6, 358-363 Detection Protocol for Neural Activity: Use Phospholipids to Intercalate Cell Membrane Detect Voltage Drops Across Cell During Neural Activity 100 mV drop over 5 nm (E=200kV/cm) Estimated NV E-Field Resolution 10kV/cm Proposed Linking Chemistry: Exploit Carboxylate Groups Synthesize Diaminoethyleneglycol oligomers Phosphatetriester Hydrolysis Phosphatidylethoxyamine Terminated Surface Ox. HPHT NDs Raman NEXAFS FTIR TEM NEXAFS/XPS HPHT Nanodiamonds and Their Purification Peak(cm-1) Assignment ent 1280 111 Dimer mode & 110 surface chain mode 1332 Phonon mode 1370, 1400 110 Subsurface Dimer Mode 1620, 1660 Dumbbell Interstitial, Oleifinic Chain Etching of Diamond C-O Vibrations Dominate DRIFTS and C=O Sparse Found an alcohol rich surface 30:1 Minor component of higher oxidation states of carbon (acid anhydrides, acids) Alcohol:Acid 90:1 Alcohol:Acid After Piranha+Ox Near Edge X-Ray Absorption Fine Structure Probes 1sp-projected states with and symmetry (1sLUMO) l= 1 (dipole selection rules) HPHT : C-O species and Diamond Readily see 1Cs Exciton from Diamond;Not seen in Detonation NDs Can Identify LUMO Orbitals with p-orbitals ( and symmetry) HPHT NDs Similar to Bulk-Like Diamond at 5-50 nm Direct Surface Studies Conclude a Alcohol Rich Surface on 111 Minor CO2 Desorption on HPHT NDs Up To 700C Acid Anhydride to Ketone Vibrational Signature HPHT is High Quality Diamond Nanoscale Material But will the HPHT Nanodiamond Phononic, Electronic and Support a Nitrogen Vacancy Center Unlike Its Detonation Nanodiamond Crystallographic Coherence Counterpart? Alcohol Rich Surface Can Be Handled As Powder and As Colloids We Have High Quality Diamond: Leading To Stable NV Centers Single Quantum Emitter Spin Manipulation t g1 (t ) Ak exp k k k g 2 (t ) 1 g1 t 2 Optically Detected Magnetic Resonance (ODMR) Alternative Linking Chemistry : Silanization, Amination and Boronation Siloxane Chemistry produces O-Si-O-Si Network + Fxn Group of Interest Amination traditionally uses preChlorination step followed by Amination (gas phase) R-BH2 + NDs Open Challenges In Diamond Chemistry Very high density of atoms C-X bonds should be of similar atomic radii C has diverse bonding (amorphous carbon) Surface chemistry not well understood Facet 100 110 111 Carbon 15.8 22.3 18.2 atoms/ nm2 atoms/ nm2 atoms/ nm2 5.41 7.6 6.4 atoms/ nm2 atoms/ nm2 atoms/ nm2 CdSe Ferrari and Robertson, Interpretation of Raman Spectra of Disordered and Amorphous Carbon, Phys. Rev. B, 2000 Direct Amination of Surface 50% NH3 atmosphere; Nitrogen incorporation significant up to 1100C -C-H vibrational modes readily seen in FTIR R-C=N (Imines at 397) C=C-R (Pyridine-like at 400 eV) C-NH2 (405 eV) Hellgren et al, Nitrogen bonding structure in carbon nitride thin films studied by soft x-ray spectroscopy, APL, 2001 Diamonds at The Beach: SiO2 Growth TEOS as a priming molecule on diamond with alcohols Na2SiO3(Liquid Glass) is then added to increase SiO2 shell thickness Decoration with Polyethylene Glycol as Stabilizer Why Use SiO2 What Are the Advantages??? Before SiO2 plus PEG After SiO2 plus PEG Simulations of ND+SiO2+Au NPs (Alex Meng and Prof. Richard Osgood) Fluorescent Center: Nitrogen Vacancy Center with 6 electron configuration: Cube of HPHT 10 Goal: nm Simulate the fluorescence enhancement of a dipole emitter embedded in a diamond matrix with varying thicknesses of SiO2 with a Au nanoparticle at its surface. The ND with 10nm + SiO2. Under a laser radiation, due to the high refractive index, the light can barely get into the nanodiamond. Plasmon Resonance Produces Electric Field Enhancement (Antenna Effect) Au NPs enhance electric field around NVC and enhance absorption. The excited NV center will now radiate more. However, a portion of the energy it radiated will be absorbed by gold as ohmic loss (heat loss/energy transfer). Dimer Modeling Has Further Enhancement Au dimer enhances PL further. But more gold means more energy radiated by NV center will be absorbed. NDs@SiO2+Au= Light*7 7 single dimer PL Enhancement 6 5 4 3 2 1 0 0 2 4 6 8 SiO Thickness (nm) 10 12 2 The maximum PL enhancement is at SiO2 = 5nm PL enhance factor is ~7. The simulation is performed at 1nm resolution. Need Controlled Au and ND HOTSPOT Interaction Regional Control PL Enhancement Will Take Nanometer Summary, Conclusions and Musings HPHT NDs with Alcohols Bulk Like Material at 530 nm PL Enhancement with Au or Biospecific Labeling (ie. Neuronal Membrane) Active NVC SiO2 Growth + Decoration or Amine Chemistry Acknowledgements and Thanks: Edward Chen (MIT) Prof. Dirk Englund (MIT) Matt Trusheim (MIT) Prof. Rafael Yuste (CU) Chris Dupre (CU) Prof. Jon Owen (CU) Alex Meng (CU) Prof. Richard Osgood (CU) Dr. Theanne Shiros (CU) BNL-CFN, NSLS, SSRL, MRSEC Dr. Dennis Nordlund (SSRL) Keck Foundation Dr. Rosa Diaz (BNL-CFN MURI Dr. Darcy Peterka (CU) EFRC Dr. Ophir Gaathon (MIT) Thank You For Your Attention