Quantum Dots - Revision history

Bradley Monk at 02:36, 5 August 2013

2013-08-05T02:36:21Z

← Older revision		Revision as of 19:36, 4 August 2013
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	[[Category:Qual]]		[[Category:Qual]] [[Category:ReDiClus]]

Bradley Monk: /* Making Quantum Dots */

2013-06-04T02:01:29Z

Making Quantum Dots

← Older revision		Revision as of 19:01, 3 June 2013
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			*In the 2007 paper they use an [http://www.olympusmicro.com/primer/techniques/fluorescence/ix70fluorescence.html Olympus IX70] Inverted microscope.

			*We want the [http://www.nikoninstruments.com/Products/Microscope-Systems/Inverted-Microscopes/Eclipse-Ti/(key_features) Nikon Eclipse Ti] inverted microscope


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	A total of 1 μL of 655-nm Quantum dots (Qdots) conjugated (see also [http://en.wikipedia.org/wiki/Polyclonal_antibodies antibodies]) to goat (Fab‘)2 anti-mouse IgG ([http://products.invitrogen.com:80/ivgn/en/US/direct/invitrogen?cmd=catProductDetail&productID=Q11422MP Invitrogen]) were incubated with 1 μL Fab anti-GluA2 in 7 μL PBS for 20 min at room temperature. Nonspecific binding was blocked by adding 1 μL of 10% casein stock solution for 15 min (Vector Laboratories), and this solution was kept at 4 °C throughout the experiment. Neurons were incubated for 10 min at 37 °C in 1 mL culture medium containing 1 μL of the anti-GluA2-coated Qdot solution, then rinsed and mounted in an aluminum chamber containing Tyrode solution (30 mM glucose, 120 mM NaCl, 5 mM KCl, 2 mM MgCl2, 2 mM CaCl2, 25 mM Hepes) on a Nikon microscope (NIKON Eclipse TE2000-U) thermostated to 37 °C using an air blower (World Precision Instruments) and an objective heater (Bioptechs). Single Qdots were detected through a100 × 1.4 N.A. oil immersion objective, using a 100-W mercury lamp and appropriate excitation/emission filters (Chroma). Sequences of 50 s, corresponding to stacks of 1,000 images with an integration time of 50 ms, were acquired using a CCD camera (Quantem; Roper Scientific). For each coverslip, Qdots were followed on randomly selected dendritic regions (size 20 × 20 μ m) for up to 20 min. Two coverslips of each condition were processed for a total of 3 – 4 neuronal cultures. We checked for specificity of Qdot binding by preparing primary hippocampal cultures from GluA2 KO mice dissected at p0. Anti – GluA2- conjugated Qdots bound minimally to cultures from GluA2 KO compared with those prepared from wild-type littermates.		A total of 1 μL of 655-nm Quantum dots (Qdots) conjugated (see also [http://en.wikipedia.org/wiki/Polyclonal_antibodies antibodies]) to goat (Fab‘)2 anti-mouse IgG ([http://products.invitrogen.com:80/ivgn/en/US/direct/invitrogen?cmd=catProductDetail&productID=Q11422MP Invitrogen]) were incubated with 1 μL Fab anti-GluA2 in 7 μL PBS for 20 min at room temperature. Nonspecific binding was blocked by adding 1 μL of 10% casein stock solution for 15 min (Vector Laboratories), and this solution was kept at 4 °C throughout the experiment. Neurons were incubated for 10 min at 37 °C in 1 mL culture medium containing 1 μL of the anti-GluA2-coated Qdot solution, then rinsed and mounted in an aluminum chamber containing Tyrode solution (30 mM glucose, 120 mM NaCl, 5 mM KCl, 2 mM MgCl2, 2 mM CaCl2, 25 mM Hepes) on a Nikon microscope (NIKON Eclipse TE2000-U) thermostated to 37 °C using an air blower (World Precision Instruments) and an objective heater (Bioptechs). Single Qdots were detected through a100 × 1.4 N.A. oil immersion objective, using a 100-W mercury lamp and appropriate excitation/emission filters (Chroma). Sequences of 50 s, corresponding to stacks of 1,000 images with an integration time of 50 ms, were acquired using a CCD camera (Quantem; Roper Scientific). For each coverslip, Qdots were followed on randomly selected dendritic regions (size 20 × 20 μ m) for up to 20 min. Two coverslips of each condition were processed for a total of 3 – 4 neuronal cultures. We checked for specificity of Qdot binding by preparing primary hippocampal cultures from GluA2 KO mice dissected at p0. Anti – GluA2- conjugated Qdots bound minimally to cultures from GluA2 KO compared with those prepared from wild-type littermates.

	*In the 2007 paper they use an [http://www.olympusmicro.com/primer/techniques/fluorescence/ix70fluorescence.html Olympus IX70] Inverted microscope.

	===Antibodies and drugs.===		===Antibodies and drugs.===

Bradley Monk: /* Single-Nanoparticle Tracking. */

2013-06-04T01:53:10Z

Single-Nanoparticle Tracking.

← Older revision		Revision as of 18:53, 3 June 2013
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	===Single-Nanoparticle Tracking. ===		===Single-Nanoparticle Tracking. ===
	A total of 1 μL of 655-nm Quantum dots (Qdots) conjugated (see also [http://en.wikipedia.org/wiki/Polyclonal_antibodies antibodies]) to goat (Fab‘)2 anti-mouse IgG ([http://products.invitrogen.com:80/ivgn/en/US/direct/invitrogen?cmd=catProductDetail&productID=Q11422MP Invitrogen]) were incubated with 1 μL Fab anti-GluA2 in 7 μL PBS for 20 min at room temperature. Nonspecific binding was blocked by adding 1 μL of 10% casein stock solution for 15 min (Vector Laboratories), and this solution was kept at 4 °C throughout the experiment. Neurons were incubated for 10 min at 37 °C in 1 mL culture medium containing 1 μL of the anti-GluA2-coated Qdot solution, then rinsed and mounted in an aluminum chamber containing Tyrode solution (30 mM glucose, 120 mM NaCl, 5 mM KCl, 2 mM MgCl2, 2 mM CaCl2, 25 mM Hepes) on a Nikon microscope (NIKON Eclipse TE2000-U) thermostated to 37 °C using an air blower (World Precision Instruments) and an objective heater (Bioptechs). Single Qdots were detected through a100 × 1.4 N.A. oil immersion objective, using a 100-W mercury lamp and appropriate excitation/emission filters (Chroma). Sequences of 50 s, corresponding to stacks of 1,000 images with an integration time of 50 ms, were acquired using a CCD camera (Quantem; Roper Scientific). For each coverslip, Qdots were followed on randomly selected dendritic regions (size 20 × 20 μ m) for up to 20 min. Two coverslips of each condition were processed for a total of 3 – 4 neuronal cultures. We checked for specificity of Qdot binding by preparing primary hippocampal cultures from GluA2 KO mice dissected at p0. Anti – GluA2- conjugated Qdots bound minimally to cultures from GluA2 KO compared with those prepared from wild-type littermates.		A total of 1 μL of 655-nm Quantum dots (Qdots) conjugated (see also [http://en.wikipedia.org/wiki/Polyclonal_antibodies antibodies]) to goat (Fab‘)2 anti-mouse IgG ([http://products.invitrogen.com:80/ivgn/en/US/direct/invitrogen?cmd=catProductDetail&productID=Q11422MP Invitrogen]) were incubated with 1 μL Fab anti-GluA2 in 7 μL PBS for 20 min at room temperature. Nonspecific binding was blocked by adding 1 μL of 10% casein stock solution for 15 min (Vector Laboratories), and this solution was kept at 4 °C throughout the experiment. Neurons were incubated for 10 min at 37 °C in 1 mL culture medium containing 1 μL of the anti-GluA2-coated Qdot solution, then rinsed and mounted in an aluminum chamber containing Tyrode solution (30 mM glucose, 120 mM NaCl, 5 mM KCl, 2 mM MgCl2, 2 mM CaCl2, 25 mM Hepes) on a Nikon microscope (NIKON Eclipse TE2000-U) thermostated to 37 °C using an air blower (World Precision Instruments) and an objective heater (Bioptechs). Single Qdots were detected through a100 × 1.4 N.A. oil immersion objective, using a 100-W mercury lamp and appropriate excitation/emission filters (Chroma). Sequences of 50 s, corresponding to stacks of 1,000 images with an integration time of 50 ms, were acquired using a CCD camera (Quantem; Roper Scientific). For each coverslip, Qdots were followed on randomly selected dendritic regions (size 20 × 20 μ m) for up to 20 min. Two coverslips of each condition were processed for a total of 3 – 4 neuronal cultures. We checked for specificity of Qdot binding by preparing primary hippocampal cultures from GluA2 KO mice dissected at p0. Anti – GluA2- conjugated Qdots bound minimally to cultures from GluA2 KO compared with those prepared from wild-type littermates.

			*In the 2007 paper they use an [http://www.olympusmicro.com/primer/techniques/fluorescence/ix70fluorescence.html Olympus IX70] Inverted microscope.

	===Antibodies and drugs.===		===Antibodies and drugs.===

Bradley Monk at 00:22, 23 May 2013

2013-05-23T00:22:25Z

← Older revision		Revision as of 17:22, 22 May 2013
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			{{QualHeader}}
	[[File:Qdot core shell.png\|thumb\|left\|300px\|In		[[File:Qdot core shell.png\|thumb\|left\|300px\|In
	this schematic of the overall structure of a Qdot®		this schematic of the overall structure of a Qdot®

Bradley Monk at 00:21, 23 May 2013

2013-05-23T00:21:24Z

← Older revision		Revision as of 17:21, 22 May 2013
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	*[http://www.nature.com/neuro/journal/v12/n7/full/nn.2338.html#online-methods Choquet Methods]		*[http://www.nature.com/neuro/journal/v12/n7/full/nn.2338.html#online-methods Choquet Methods]
	[http://www.bdbiosciences.com/ptProduct.jsp?prodId=29038&catyId=745783&page=product&wcm_page=/research/neuroscience/productlist/reagentsassays.jsp&wcm_title=Research%20Applications%20-%20Neuroscience%20-%20Product%20List%20-%20Reagents%20and%20Assays&wcm_category=745783 GluR2 Primary Antibody]		[http://www.bdbiosciences.com/ptProduct.jsp?prodId=29038&catyId=745783&page=product&wcm_page=/research/neuroscience/productlist/reagentsassays.jsp&wcm_title=Research%20Applications%20-%20Neuroscience%20-%20Product%20List%20-%20Reagents%20and%20Assays&wcm_category=745783 GluR2 Primary Antibody]


			[[Category:Qual]]

Monakhos at 12:48, 12 May 2013

2013-05-12T12:48:17Z

← Older revision		Revision as of 05:48, 12 May 2013
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	[[File:Fab.png\|thumb\|200px]]		[[File:Fab.png\|thumb\|200px]]
	Quantum dots are conjugated with an [http://en.wikipedia.org/wiki/Immunoglobulin_G IgG] antibody, this antibody is in the form of a [http://en.wikipedia.org/wiki/Fragment_antigen_binding Fab Fragment] (specifically a '''F(ab’)2''' fragment). This construct of QD-Fab, is your secondary antibody construct, which will recognize IgG antibodies of a given species. This is incubated with primary antibody (IgG) specific to the protein of interest (AMPAR).		Quantum dots are conjugated with an [http://en.wikipedia.org/wiki/Immunoglobulin_G IgG] antibody, this antibody is in the form of a [http://en.wikipedia.org/wiki/Fragment_antigen_binding Fab Fragment] (specifically a '''F(ab’)2''' fragment). This construct of QD-Fab, is your secondary antibody construct, which will recognize IgG antibodies of a given species. This is incubated with primary antibody (IgG) specific to the protein of interest ([[AMPAR]]).


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	The extra cellular medium contained 145 mM NaCl, 2.5 mM KCl, 2 mM MgCl2, 2 mM CaCl2, 10 mM HEPES and 10 mM D-glucose (pH 7.4). To block GABAA receptors, we added 50 M picrotoxin to the extra cellular medium. The bath temperature was kept at 33–35 °C. Borosilicate pipettes were used to produce patch electrodes with resistances of 3–5 M . A standard pipette solution was used to characterize neuronal properties in voltage and current-clamp conditions during development (Supplementary Fig. 7) and contained 140 mM potassium gluconate, 2 mM MgCl2, 4 mM NaATP, 0.1 mM EGTA, 10 mM HEPES, 10 mM phosphocreatine, 0.4 mM GTP (pH 7.25). To record mEPSC and to decrease space-clamp difficulties, we used another recording solution 125 mM CH3CsSO3, 2 mM MgCl2, 1 mM CaCl2, 4 mM NaATP, 10 mM EGTA, 10 mM HEPES and 0.4 mM GTP (pH 7.25).		The extra cellular medium contained 145 mM NaCl, 2.5 mM KCl, 2 mM MgCl2, 2 mM CaCl2, 10 mM HEPES and 10 mM D-glucose (pH 7.4). To block GABAA receptors, we added 50 M picrotoxin to the extra cellular medium. The bath temperature was kept at 33–35 °C. Borosilicate pipettes were used to produce patch electrodes with resistances of 3–5 M . A standard pipette solution was used to characterize neuronal properties in voltage and current-clamp conditions during development (Supplementary Fig. 7) and contained 140 mM potassium gluconate, 2 mM MgCl2, 4 mM NaATP, 0.1 mM EGTA, 10 mM HEPES, 10 mM phosphocreatine, 0.4 mM GTP (pH 7.25). To record mEPSC and to decrease space-clamp difficulties, we used another recording solution 125 mM CH3CsSO3, 2 mM MgCl2, 1 mM CaCl2, 4 mM NaATP, 10 mM EGTA, 10 mM HEPES and 0.4 mM GTP (pH 7.25).
	Recordings in voltage and current clamp mode were performed with an EPC10 double patch-clamp amplifier (HEKA Electronics). Data were acquired and stored using Pulse-Pulse fit software version 8.62 (HEKA Electronics, Lambrecht, Germany) and analyzed with IGOR (WaveMetrics) and GraphPad Prism software.		Recordings in voltage and current clamp mode were performed with an EPC10 double patch-clamp amplifier (HEKA Electronics). Data were acquired and stored using Pulse-Pulse fit software version 8.62 (HEKA Electronics, Lambrecht, Germany) and analyzed with IGOR (WaveMetrics) and GraphPad Prism software.
	Spontaneous events were analyzed by Minianalysis (Synaptosoft). Local activation of receptors was performed by iontophoresis of glutamate using an amplifier from NPI Electronics. Pipettes for iontophoretic stimulation had resistances between 40–60 M when filled with 150 mM sodium glutamate (pH 7.4). A small retaining current was needed to keep glutamate inside the pipette (usually between 10–50 nA). Current pulses between 30 and 600 nA and 1–2 ms duration were required to evoke AMPAR-mediated currents between amplitudes of 30–600 pA under control conditions.		Spontaneous events were analyzed by Minianalysis (Synaptosoft). Local activation of receptors was performed by iontophoresis of glutamate using an amplifier from NPI Electronics. Pipettes for iontophoretic stimulation had resistances between 40–60 M when filled with 150 mM sodium glutamate (pH 7.4). A small retaining current was needed to keep glutamate inside the pipette (usually between 10–50 nA). Current pulses between 30 and 600 nA and 1–2 ms duration were required to evoke [[AMPAR]]-mediated currents between amplitudes of 30–600 pA under control conditions.

Monakhos: /* Making Quantum Dots */

2013-05-02T09:27:27Z

Making Quantum Dots

← Older revision		Revision as of 02:27, 2 May 2013
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	[[File:Fab.png\|thumb\|200px]]		[[File:Fab.png\|thumb\|200px]]
	Quantum dots are conjugated with an [http://en.wikipedia.org/wiki/Immunoglobulin_G IgG] antibody, this antibody is in the form of a [http://en.wikipedia.org/wiki/Fragment_antigen_binding Fab Fragment] (specifically a '''F(ab’)2''' fragment). This ~~entire~~ construct, QD~~-IgG~~-Fab, is your secondary antibody construct, which will recognize IgG antibodies of a given species. This is incubated with primary antibody specific to the protein of interest~~, in this case AMPA receptors~~.		Quantum dots are conjugated with an [http://en.wikipedia.org/wiki/Immunoglobulin_G IgG] antibody, this antibody is in the form of a [http://en.wikipedia.org/wiki/Fragment_antigen_binding Fab Fragment] (specifically a '''F(ab’)2''' fragment). This construct of QD-Fab, is your secondary antibody construct, which will recognize IgG antibodies of a given species. This is incubated with primary antibody (IgG) specific to the protein of interest (AMPAR).


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	===FLIP.===		===FLIP.===
	For FLIP experiments, the laser beam was parked at the dendritic shaft at a power of 10% and a additional 75% intensity filter was used to avoid photodamage in the continuous bleached region. Continuous laser illumination was interrupted during image acquisition at a frequency of 0.2 Hz. Control of surface expression and experimental conditions were similar to those for the FRAP experiments described above.		For FLIP experiments, the laser beam was parked at the dendritic shaft at a power of 10% and a additional 75% intensity filter was used to avoid photodamage in the continuous bleached region. Continuous laser illumination was interrupted during image acquisition at a frequency of 0.2 Hz. Control of surface expression and experimental conditions were similar to those for the FRAP experiments described above.



	==Vendors==		==Vendors==

Monakhos at 09:25, 2 May 2013

2013-05-02T09:25:55Z

← Older revision		Revision as of 02:25, 2 May 2013
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	[[File:Qdot core shell.png\|thumb\|300px\|In		[[File:Qdot core shell.png\|thumb\|left\|300px\|In
	this schematic of the overall structure of a Qdot®		this schematic of the overall structure of a Qdot®
	nanocrystal streptavidin conjugate, the layers		nanocrystal streptavidin conjugate, the layers
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	Qdot. 625 streptavidin and goat anti–mouse IgG and anti– rabbit IgG secondary antibody conjugates provide a high level of resolution and brightness for immunostaining of cells grown in culture (Figure 8). For those who wish to conjugate their own antibodies to these ultrabright nanocrystals, the Qdot. 625 Antibody Conjugation Kit is available.		Qdot. 625 streptavidin and goat anti–mouse IgG and anti– rabbit IgG secondary antibody conjugates provide a high level of resolution and brightness for immunostaining of cells grown in culture (Figure 8). For those who wish to conjugate their own antibodies to these ultrabright nanocrystals, the Qdot. 625 Antibody Conjugation Kit is available.

			Stated simply, quantum dots are semiconductors whose electronic characteristics are closely related to the size and shape of the individual crystal. Generally, the smaller the size of the crystal, the larger the band gap, the greater the difference in energy between the highest valence band and the lowest conduction band becomes, therefore more energy is needed to excite the dot, and concurrently, more energy is released when the crystal returns to its resting state. For example, in fluorescent dye applications, this equates to higher frequencies of light emitted after excitation of the dot as the crystal shrinks to smaller sizes, resulting in a color shift from red to blue in the light emitted. In addition to such tuning, a main advantage with quantum dots is that, because of the high level of control possible over the size of the crystals produced, it is possible to have very precise control over the conductive properties of the material.[6] Quantum dots of different sizes can be assembled into a gradient multi-layer nanofilm.

			{{Clear}}
	==Making Quantum Dots==		==Making Quantum Dots==

	Here's the way I understand it.		Here's the way I understand it.

	~~To create a quantum dot that will tag AMPA receptors choose a quantum dot~~ conjugated to an [http://en.wikipedia.org/wiki/Immunoglobulin_G IgG] antibody ~~that also has~~ a ~~fragment antigen-binding region (aka F(ab’)2 or~~ [http://en.wikipedia.org/wiki/Fragment_antigen_binding Fab] fragment~~, the part of an antibody that binds antigens~~). This entire construct, QD-IgG-Fab, is your secondary antibody construct ~~and the~~ IgG ~~and Fab are usually from different host animals~~. This is ~~then~~ incubated with primary antibody ~~fragment (Fab) that is~~ specific to the protein of interest, in this case AMPA receptors.		[[File:Fab.png\|thumb\|200px]]
			Quantum dots are conjugated with an [http://en.wikipedia.org/wiki/Immunoglobulin_G IgG] antibody, this antibody is in the form of a [http://en.wikipedia.org/wiki/Fragment_antigen_binding Fab Fragment] (specifically a '''F(ab’)2''' fragment). This entire construct, QD-IgG-Fab, is your secondary antibody construct, which will recognize IgG antibodies of a given species. This is incubated with primary antibody specific to the protein of interest, in this case AMPA receptors.


	*[https://www.invitrogen.com/site/us/en/home/brands/Molecular-Probes/Key-Molecular-Probes-Products/Qdot/qdot_reg__nanocrystal.html Invitrogen Quantum Dots]
	*[http://www.bdbiosciences.com/ecat/txDetailedTable.jsp?from=simpleTable&action=SELECT&form=formTree_catBean&item=745783&size=20&wcm_page=/research/neuroscience/productlist/reagentsassays.jsp&wcm_title=Research%20Applications%20-%20Neuroscience%20-%20Product%20List%20-%20Reagents%20and%20Assays&wcm_category=745783 BD Biosciences]
	*[http://www.nature.com/neuro/journal/v12/n7/full/nn.2338.html#online-methods Choquet Methods]
	[http://www.bdbiosciences.com/ptProduct.jsp?prodId=29038&catyId=745783&page=product&wcm_page=/research/neuroscience/productlist/reagentsassays.jsp&wcm_title=Research%20Applications%20-%20Neuroscience%20-%20Product%20List%20-%20Reagents%20and%20Assays&wcm_category=745783 GluR2 Primary Antibody]


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	===Antibodies and drugs.===		===Antibodies and drugs.===
	~~[[File:Fab.png\|thumb\|200px]]~~
	The antibody to the [http://www.ncbi.nlm.nih.gov/pubmed/7993626 N-terminal epitope of the GluR1 subunit] was described previously46. We used a commercial antibody to an N-terminal epitope of the GluR2 subunit to detect GluR2 ([http://www.bdbiosciences.com/ecat/ BD Pharmigen]).		The antibody to the [http://www.ncbi.nlm.nih.gov/pubmed/7993626 N-terminal epitope of the GluR1 subunit] was described previously46. We used a commercial antibody to an N-terminal epitope of the GluR2 subunit to detect GluR2 ([http://www.bdbiosciences.com/ecat/ BD Pharmigen]).
	AMPA receptor labeling and synaptic live staining.		AMPA receptor labeling and synaptic live staining.
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	==Vendors==		==Vendors==
			*[https://www.invitrogen.com/site/us/en/home/brands/Molecular-Probes/Key-Molecular-Probes-Products/Qdot/qdot_reg__nanocrystal.html Invitrogen Quantum Dots]
			*[http://www.bdbiosciences.com/ecat/txDetailedTable.jsp?from=simpleTable&action=SELECT&form=formTree_catBean&item=745783&size=20&wcm_page=/research/neuroscience/productlist/reagentsassays.jsp&wcm_title=Research%20Applications%20-%20Neuroscience%20-%20Product%20List%20-%20Reagents%20and%20Assays&wcm_category=745783 BD Biosciences]
			*[http://www.nature.com/neuro/journal/v12/n7/full/nn.2338.html#online-methods Choquet Methods]
			[http://www.bdbiosciences.com/ptProduct.jsp?prodId=29038&catyId=745783&page=product&wcm_page=/research/neuroscience/productlist/reagentsassays.jsp&wcm_title=Research%20Applications%20-%20Neuroscience%20-%20Product%20List%20-%20Reagents%20and%20Assays&wcm_category=745783 GluR2 Primary Antibody]

Monakhos at 09:07, 2 May 2013

2013-05-02T09:07:26Z

← Older revision		Revision as of 02:07, 2 May 2013
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	Howarth and colleagues have achieved real-time imaging of the complex formed between a single ligand-labeled nanocrystal and its target receptor on live neurons,7 an approach whose success these authors attribute in part to the brightness inherent in the nanocrystal particles. Furthermore, cells and tissues labeled with Qdot. nanocrystals can be archived permanently and reanalyzed with the same level of sensitivity as achieved in the initial assay.		Howarth and colleagues have achieved real-time imaging of the complex formed between a single ligand-labeled nanocrystal and its target receptor on live neurons,7 an approach whose success these authors attribute in part to the brightness inherent in the nanocrystal particles. Furthermore, cells and tissues labeled with Qdot. nanocrystals can be archived permanently and reanalyzed with the same level of sensitivity as achieved in the initial assay.

	[[File:Qdot tubulin.png\|thumb~~\|left~~\|300px\|Qdot® 625 goat anti-mouse conjugate immunolabeling of microtubules in		[[File:Qdot tubulin.png\|thumb\|300px\|Qdot® 625 goat anti-mouse conjugate immunolabeling of microtubules in
	HeLa cells. Fixed and permeabilized HeLa cells were labeled with mouse anti–		HeLa cells. Fixed and permeabilized HeLa cells were labeled with mouse anti–
	α-tubulin primary antibody and 20 nM Qdot® 625 goat anti–mouse IgG.]]		α-tubulin primary antibody and 20 nM Qdot® 625 goat anti–mouse IgG.]]

Monakhos at 09:06, 2 May 2013

2013-05-02T09:06:13Z

← Older revision		Revision as of 02:06, 2 May 2013
Line 1:		Line 1:
	[[File:Qdot ~~Nanocrystal~~.png\|thumb\|300px]]		[[File:Qdot core shell.png\|thumb\|300px\|In
			this schematic of the overall structure of a Qdot®
			nanocrystal streptavidin conjugate, the layers
			represent the distinct structural elements and are
			roughly to scale.]]

	Quantum Dot nanocrystals are fluorophores—substances that absorb photons of light, then reemit photons at a different wavelength.1–3 However, simple comparisons with organic fluorescent dyes and naturally fluorescent proteins end there. Qdot. nanocrystal conjugates combine exceptional fluorescence with full biofunctionality for a wide variety of life science applications. This combination is especially important for those applications requiring excellent photostability and multicolor detection from a single excitation source.		Quantum Dot nanocrystals are fluorophores—substances that absorb photons of light, then reemit photons at a different wavelength.1–3 However, simple comparisons with organic fluorescent dyes and naturally fluorescent proteins end there. Qdot. nanocrystal conjugates combine exceptional fluorescence with full biofunctionality for a wide variety of life science applications. This combination is especially important for those applications requiring excellent photostability and multicolor detection from a single excitation source.

	[[File:Qdot scale.png\|thumb\|500px]]		[[File:Qdot scale.png\|thumb\|500px\|Relative size (hydrodynamic diameter in nm) of Qdot® nanocrystals. Qdot® nanocrystals are roughly
			protein-sized clusters of semiconductor material.]]

	Qdot nanocrystals are nanometer-scale (roughly protein-sized) atom clusters comprising a core, shell, and coating (Figures 1 and 2). The core is made up of a few hundred to a few thousand atoms of a semiconductor material (often cadmium mixed with selenium or tellurium). A semiconductor shell (zinc sulfide) surrounds and stabilizes the core, improving both the optical and physical properties of the material. An amphiphilic polymer coating then encases this core and shell, providing a water-soluble surface that can be differentially modified to create Qdot. nanocrystals that meet specific assay requirements.		Qdot nanocrystals are nanometer-scale (roughly protein-sized) atom clusters comprising a core, shell, and coating (Figures 1 and 2). The core is made up of a few hundred to a few thousand atoms of a semiconductor material (often cadmium mixed with selenium or tellurium). A semiconductor shell (zinc sulfide) surrounds and stabilizes the core, improving both the optical and physical properties of the material. An amphiphilic polymer coating then encases this core and shell, providing a water-soluble surface that can be differentially modified to create Qdot. nanocrystals that meet specific assay requirements.
	~~[[File:Qdot core shell.png\|thumb\|300px]]~~

	Howarth and colleagues have achieved real-time imaging of the complex formed between a single ligand-labeled nanocrystal and its target receptor on live neurons,7 an approach whose success these authors attribute in part to the brightness inherent in the nanocrystal particles. Furthermore, cells and tissues labeled with Qdot. nanocrystals can be archived permanently and reanalyzed with the same level of sensitivity as achieved in the initial assay.		Howarth and colleagues have achieved real-time imaging of the complex formed between a single ligand-labeled nanocrystal and its target receptor on live neurons,7 an approach whose success these authors attribute in part to the brightness inherent in the nanocrystal particles. Furthermore, cells and tissues labeled with Qdot. nanocrystals can be archived permanently and reanalyzed with the same level of sensitivity as achieved in the initial assay.

	[[File:Qdot tubulin.png\|thumb\|left\|300px]]		[[File:Qdot tubulin.png\|thumb\|left\|300px\|Qdot® 625 goat anti-mouse conjugate immunolabeling of microtubules in
			HeLa cells. Fixed and permeabilized HeLa cells were labeled with mouse anti–
			α-tubulin primary antibody and 20 nM Qdot® 625 goat anti–mouse IgG.]]
	Qdot. 625 streptavidin and goat anti–mouse IgG and anti– rabbit IgG secondary antibody conjugates provide a high level of resolution and brightness for immunostaining of cells grown in culture (Figure 8). For those who wish to conjugate their own antibodies to these ultrabright nanocrystals, the Qdot. 625 Antibody Conjugation Kit is available.		Qdot. 625 streptavidin and goat anti–mouse IgG and anti– rabbit IgG secondary antibody conjugates provide a high level of resolution and brightness for immunostaining of cells grown in culture (Figure 8). For those who wish to conjugate their own antibodies to these ultrabright nanocrystals, the Qdot. 625 Antibody Conjugation Kit is available.