Apparatus and method for electrophoretic microspot concentration

An apparatus for the concentration and detection of biomolecules in a sample, comprising:

• a first compartment for containing a first buffer to which a sample containing biomolecules is added;
• a second compartment for containing a second buffer including no sample;
• an insulation wall separating the first compartment and the second compartment, said insulation wall having a channel filled with a gel for electrophoresis, said channel covered with an insulation sheet except for one end spot of the channel, said insulation wall having a hole underneath the end spot, said hole being covered with a membrane, wherein when the sample is loaded, the first buffer and the second buffer are insulated by the insulation wall except for a place where the end spot and the hole are located and the gel is present therebetween, wherein the first buffer and the second buffer are in electrical contact with each other via the gel;
• a first electrode provided in the first compartment to contact the first buffer when loaded;
• a second electrode provide in the second compartment to contact the second buffer when loaded, wherein when a voltage is applied between the first and the second electrodes, biomolecules in the sample are subjected to electrophoresis and concentrated at the end spot;
• and
• a third electrode provided at another end of the channel opposite to the end spot, wherein a voltage is applied between the second electrode and the third electrode, biomolecules concentrated at the end spot are subjected to electrophoresis along the channel toward the third electrode.

44 A method for the concentration and detection of a biomolecule in a sample, comprising:

• applying a sample to a first buffer, said first buffer being separated from a second buffer by an insulation wall having a channel filled with a gel for electrophoresis, said channel covered with an insulation sheet except for one end spot of the channel, said insulation wall having a hole underneath the end spot, said hole being covered with a membrane, wherein the first buffer and the second buffer are insulated by the insulation wall except for a place where the end spot and the hole are located and the gel is present therebetween, wherein the first buffer and the second buffer are in electrical contact with each other via the gel;
• imposing a voltage difference between the first and the second buffers to subject biomolecules in the sample to electrophoresis, thereby concentrating the biomolecules at the end spot;
• and
• imposing a voltage difference between another end of the channel opposite to the end spot and the second buffer to subject the biomolecules concentrated at the end spot to electrophoresis along the channel toward the other end of the channel.