Lossless cryo-grid preparation stage for high-resolution electron microscopy
The invention relates to a preparation system and method for preparing a sample for electron microscopy, the preparation system comprising: a liquid handling system ( 0 ) comprising a dispensing head ( 1 ), wherein said liquid handling system ( 0 ) is configured to aspirate and dispense a volume of a sample via the dispensing head ( 1 ), a support structure ( 2 ) that is configured to accommodate the sample, a temperature-controlled stage ( 4 ) that is configured to keep said support structure ( 2 ) at a pre-defined temperature, a first adapter ( 3 ) configured to hold said support structure ( 2 ), and a transfer mechanism ( 60 ) that is configured to be connected to the first adapter ( 3 ) holding the support structure ( 2 ) and to move said support structure ( 2 ) into a container ( 8 ) containing a liquid cryogen ( 80 ) so that the sample on the support structure ( 2 ) contacts the cryogen ( 80 ).
1. A preparation system for preparing a sample for electron microscopy, comprising:
a liquid handling system ( 0 ) comprising a dispensing head ( 1 ), wherein said liquid handling system ( 0 ) is configured to aspirate and dispense a volume of the sample via the dispensing head ( 1 ),
a support structure ( 2 ) that is configured to accommodate the sample,
a temperature-controlled stage ( 4 ) comprising a peltier element ( 4 a ), a peltier controller ( 4 b ) controlling the peltier element and a temperature sensor ( 4 c ) mounted on the temperature-controlled stage to keep said support structure ( 2 ) at a pre-defined temperature, the temperature-controlled stage comprising a surface to allow positioning of the support structure on the surface of the temperature-controlled stage to provide thermal contact between the support structure and the temperature-controlled stage,
a first adapter ( 3 ) configured to hold said support structure ( 2 ),
a transfer mechanism ( 60 ) that is configured to be connected via a second adapter ( 30 ) of the transfer mechanism ( 60 ) to the first adapter ( 3 ) holding the support structure ( 2 ), wherein the transfer mechanism ( 60 ) comprises a hinge ( 61 ) to pivot an assembly comprising the first and the second adapter ( 3 , 30 ) and the support structure ( 2 ) from a horizontal position into a vertical position above a container ( 8 ), and wherein the transfer mechanism ( 60 ) comprises a switch ( 7 ) that is closed by the assembly in the vertical position activating the transfer mechanism to move the assembly ( 3 , 30 , 2 ) downwards after said pivoting so that the sample on the support structure ( 2 ) contacts a liquid cryogen ( 80 ) in the container ( 8 ), and
a translation stage assembly ( 5 ) comprising multiple motorized linear stages configured to move the temperature-controlled stage ( 4 ) relative to the liquid handling system ( 0 ), such that the dispensing head ( 1 ) and the support structure ( 2 ) can be brought in close proximity to each other so as to transfer the sample from the liquid handling system ( 0 ) to the support structure ( 2 ).
2. The preparation system according to claim 1 , characterized in that the preparation system comprises an adjustment means ( 40 ) configured to hold the first adapter ( 3 ) with respect to the temperature-controlled stage ( 4 ) in an adjustable manner.
3. The preparation system according to claim 2 , characterized in that the adjustment means ( 40 ) comprises a holding means ( 50 ) that is configured to releasably hold the first adapter ( 3 ).
4. The preparation system according to claim 1 , characterized in that the transfer mechanism ( 60 ) comprises a movement generating means that is configured to move the assembly comprising the second adapter ( 30 ), the first adapter and the support structure downwards when the assembly is positioned above the container ( 8 ) in said vertical position, so that the sample on the support structure ( 2 ) contacts the cryogen ( 80 ) in the container ( 8 ).
5. The preparation system according to claim 1 , characterized in that the preparation system comprises a means ( 15 ) for estimating a film thickness of the sample layer deposited on the support structure.
6. The preparation system according to claim 1 , characterized in that the dispensing head ( 1 ) is formed by a capillary ( 1 b ) at an end of the liquid handling system ( 0 ), which capillary comprises a tip for accommodating the sample.
7. The preparation system according to claim 1 , characterized in that the preparation system comprises a first reservoir ( 100 ), into which the dispensing head ( 1 ) containing a nanoliter volume of the sample can be immersed.
8. The preparation system according to claim 1 , characterized in that the preparation system comprises a reservoir from which the dispensing head ( 1 ) containing a nanoliter volume of the sample can aspirate a volume containing cognitive molecules.
9. The preparation system according to claim 3 , characterized in that the holding means is formed as an electromagnet ( 50 ).
10. The preparation system according to claim 4 , characterized in that the movement generating means comprises a solenoid ( 6 ).
11. The preparation system according to claim 6 , characterized in that the capillary is a microcapillary ( 1 b ).
12. A preparation system for preparing a sample for electron microscopy, comprising:
a liquid handling system ( 0 ) comprising a dispensing head ( 1 ), wherein said liquid handling system ( 0 ) is configured to aspirate and dispense a volume of the sample via the dispensing head ( 1 ),
a support structure ( 2 ) that is configured to accommodate the sample,
a stage ( 4 ) configured to place the support structure thereon such that the support structure is in thermal contact with the stage ( 4 ),
a first adapter ( 3 ) configured to hold said support structure ( 2 ),
a transfer mechanism ( 60 ) that is configured to be connected to the first adapter ( 3 ) holding the support structure ( 2 ) and to move said support structure ( 2 ) into a container ( 8 ) containing a liquid cryogen ( 80 ) so that the sample on the support structure ( 2 ) contacts the cryogen ( 80 ), wherein the transfer mechanism ( 60 ) comprises a hinge configured to let the first adapter ( 3 ) together with the support structure ( 2 ) fall under the action of gravity in a pivoting motion from a horizontal position into a vertical position above the container ( 8 ), and wherein the transfer mechanism ( 60 ) is configured to move the first adapter ( 3 ) and the support structure ( 2 ) downwards after said pivoting so that the sample on the support structure ( 2 ) contacts the cryogen ( 80 ) in the container ( 8 ).