Integrated sample processing system
An integrated sample purification system includes a housing, a sample container rack, a filter holder, and a cylindrical magnet. The sample container rack and the filter device holder are disposed in the housing. The sample container rack is configured to hold one or more sample containers, the filter device holder is configured to hold one or more filter devices. The cylindrical magnet is adjacent to and external to the sample container rack, and is rotated about a central, longitudinal axis of the magnet by an electric motor disposed in the housing to lyse cells. Molecules of interest in the lysed cells are purified using filters that bind specifically to the molecules of interest. The system is readily amenable to automation and rapid purification and analysis of molecules of interest, such as nucleic acids and proteins.
1. A method for purifying molecules of interest from a sample with a sample purification system that comprises:
a housing;
an electric motor disposed in the housing; a sample container rack disposed in the housing, wherein the sample container rack is configured to hold one or more sample containers,
a filter device holder disposed in the housing, wherein the filter holder is configured to hold one or more filter devices, wherein each of the filter devices comprises a filter matrix for binding molecules of interest; and
a cylindrical magnet adjacent to the side of the sample container rack and external to the sample container rack, wherein
the magnet rotates around a central, longitudinal axis of the magnet by an electric motor disposed in the housing and is located above the bottom of the sample container rack,
wherein the method comprises following steps
placing a sample container containing a liquid sample suspension, a magnetic stirrer and cell lysis beads on the sample container rack;
homogenizing the liquid sample suspension in the sample container by rotating the cylindrical magnet at a speed such that cells in the sample suspension in the sample container are lysed by the magnetic stirrer and cell lysis beads;
flowing the homogenized liquid sample suspension through the filter matrix of a filter device from the one or more filter devices under conditions such that the molecules of interest bind to the filter matrix, wherein the filter device is mounted on the filter device holder;
washing the filters matrix of the filter device and
eluting the molecules of interest bound to the filter matrix from the filter device, thereby purifying the molecules of interest from the sample.
2. The method of claim 1 , wherein the sample container is pre-packed with one or more items selected from the group consisting of the magnetic stirrers, the cell lysis beads, reagents that facilitate cell lysis and reagents that preserve the integrity of the molecules of interest.
3. The method of claim 1 , wherein the molecules of interest are nucleic acids.
4. The method of claim 3 , wherein the liquid sample suspension comprises sputum.
5. The method of claim 4 , wherein the molecules of interest are nucleic acids and further comprising the step of amplifying the molecules of interest eluted from the filter device with primers specific for Mycobacterium tuberculosis and determining whether the molecules of interest comprise Mycobacterium tuberculosis DNA.
6. The method of claim 1 , wherein the cylindrical magnet has two magnetic poles symmetrically disposed along the longitudinal axis of the magnet.
7. The method of claim 1 , wherein the cylindrical magnet has opposing magnetic poles disposed at two opposite ends of the magnet.
8. The method of claim 1 , wherein the cell lysis beads are silica beads having diameters within a range from 10 μm to 1000 μm.
9. The method of claim 1 , wherein the magnetic stirrer comprises an alloy core coated with a polymer.
10. The method of claim 9 , wherein the alloy core of the magnetic stirrer comprises neodymium iron boron or samarium cobalt and wherein the polymer is polytetrafluoroethylene (PTFE) car parylene.