Method and apparatus for concentrating and/or positioning particles or cells

A method for concentrating and positioning particles or cells comprising:

• placing a liquid medium containing particles and/or cells over a surface having an electrode array associated with the surface,
• applying an alternating voltage to the electrode array to create an electric field above the surface within the medium to repel the particles or cells from the electrode array and thereby levitate the particles or cells above the surface, within the medium, by negative dielectrophoresis, and
• heating the liquid medium so as to cause convection currents to circulate within the medium which relocate the particles or cells substantially in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.

A method for concentrating particles and/or cells comprising:

• placing a liquid medium containing the particles and/or cells over a surface having an electrode array associated with the surface,
• applying an alternating voltage to the electrode array to repel the particles or cells from the electrode array and thereby levitate the particles or cells above the surface, within the medium, by negative dielectrophoresis, and
• heating the liquid medium so as to cause convection currents to circulate within the medium including rising currents centrally within the medium over the electrode array which relocate the particles or cells in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.

A method for repositioning particles and/or cells within a liquid medium comprising:

• subjecting the particles and/or cells to an electric field within the medium which repels the particles or cells to thereby levitate the particles or cells within the medium,
• heating the liquid medium to cause convection currents within the medium which relocate the particles or cells in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium, and
• applying a force to cause the concentrated particles or cells to move across the medium.

A method for repositioning particles and/or cells within a liquid medium comprising:

• subjecting the particles and/or cells to an alternating voltage to create an electric field within the medium which repels the particles or cells to thereby levitate the particles or cells within the medium,
• heating the liquid medium to cause convection currents within the medium, and
• subjecting the upper part of the medium to a second electric field which reshapes a part or parts of the upper surface of the medium to thereby cause the position at which the convection currents within the medium concentrate the cells to move within the medium.

A method for separating particles or cells in a liquid medium comprising:

• subjecting the particles or cells to an electric field to levitate two or more different types of particles or cells within the medium to two or more different heights within the medium, and
• heating the medium to cause convection currents within the liquid medium which relocate the particles or cells substantially in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.

A method for separating particles or cells comprising:

• placing a liquid medium containing the particles and/or cells over a surface having an electrode array associated with the surface,
• applying an alternating voltage to the electrode array to create an electric field above the surface within the medium to repel the particles or cells from the electrode array and which thereby levitates at least two different types of particles or cells to two or more different heights above the surface, within the medium, by negative dielectrophoresis, and
• heating the liquid medium so as to cause convection currents to circulate within the medium which relocate the particles or cells substantially in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.

Apparatus for concentrating and positioning particles or cells in a liquid medium comprising:

• means to subject particles or cells to an electric field to levitate the particles or cells within the medium by negative dielectrophoresis, and
• means to heat the medium to cause convection currents within the liquid medium which relocate the particles or cells substantially in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.

Apparatus for separating particles or cells in a liquid medium comprising:

• means to subject the particles or cells to an electric field to levitate two or more different types of particles or cells within the medium to two or more different heights within the medium, and
• means to heat the medium to cause convection currents within the liquid medium which relocate the particles or cells substantially in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.

Apparatus for separating particles or cells comprising:

• means to contain a liquid medium containing the particles and/or cells over a surface having an electrode array associated with the surface,
• means for applying an alternating voltage to the electrode array to create an electric field above the surface within the medium to repel the particles or cells from the electrode array and which thereby levitates at least two different types of particles or cells to two or more different heights above the surface, within the medium, by negative dielectrophoresis, and
• means for heating the liquid medium so as to cause convection currents to circulate within the medium which relocate the particles or cells substantially in a horizontal direction and thereby concentrate and position the levitated particles or cells within the medium.