Biological samples are typically a mixture of molecules, viruses, bacteria, cells, and other particles. Considerable information can be acquired from a biological sample. However, before analysis, these samples are usually required to be separate in different components. For example, sample separation is an important step required in techniques such as PCR, gel-electrophoresis, DNA sequencing, etc. Accordingly, proper sample preparation is an important technique in the biomedical and research field. One problem associated with the current technologies is the lack of a technique that can separate and concentrate small particles from complex liquid samples. This problem is commonly seen in applications of pathogen detection and medical diagnosis. The following invention uses multiple separation methods in a synergistic fashion to allow for a more effective separation.