A lab-on-α-chip (LoC) device for size-selective particle separation, trapping, and manipulation of micro/nanoparticles from a flow of a sample solution for molecular detection, comprising: a) an in-port area for the reception of a sample solution wherein the in-port area comprises a micro pillar array being patterned with pillars having a diameter ranging from 1 to 50 μm, preferably ranging around 15 μm, with an inter-pillar spacing ranging from 1 to 50 μm, preferably ranging around 15 μm; b) a macroparticle separation area and a microparticle separation area disposed downstream of the macroparticle separation area wherein the microparticle separation area and the macroparticle separation area comprise a pillar array having pillars with a diameter in the range from 1 to 20 μm, preferably ranging around 3 μm, with an inter-pillar spacing in the range from 0.5 to 20 μm, preferably ranging around 2 to 5 μm, being connected with an area patterned with rectangular pillars in the range of 1 to 20 μm x 1 to 20 μm, preferably ranging around 5 μm x 3 μm, the rectangular pillars being rotated at an angle in the range of 30 to 70°, preferably ranging from 45 to 55°, with an interpillar spacing in the range of 1 to 10 μm in axial and lateral direction of the flow of the sample solution, preferably around 6 μm and 6.6 μm inter-pillar spacing in axial and lateral direction of the flow of the sample solution; c) a nanoparticle sorting and separation area being disposed downstream of the microparticle separation area and comprising nanochannels embedded with a deterministic lateral displacement array; said DLD array is achieved using 0.5 to 10 μm, preferably 2 μm and 1 μm, diameter pillars with 0.2 to 5 μm, preferably 1 μm and 500 nm, inter-pillar spacing; d) a functionalized nanoparticle trapping and detection area being disposed in the nanoparticle sorting and separation area and comprising a number of stages or steps (16a to 16c) that are patterned with different heights to trap different particles (18a to 18c) at different stage locations based on the particle size; said stages or steps (16a to 16c) preferably are supported with pillars to avoid pattern collapsing; and e) an out-port area for the waste sample solution. a) an in-port area for the reception of a sample solution wherein the in-port area comprises a micro pillar array being patterned with pillars having a diameter ranging from 1 to 50 μm, preferably ranging around 15 μm, with an inter-pillar spacing ranging from 1 to 50 μm, preferably ranging around 15 μm; b) a macroparticle separation area and a microparticle separation area disposed downstream of the macroparticle separation area wherein the microparticle separation area and the macroparticle separation area comprise a pillar array having pillars with a diameter in the range from 1 to 20 μm, preferably ranging around 3 μm, with an inter-pillar spacing in the range from 0.5 to 20 μm, preferably ranging around 2 to 5 μm, being connected with an area patterned with rectangular pillars in the range of 1 to 20 μm x 1 to 20 μm, preferably ranging around 5 μm x 3 μm, the rectangular pillars being rotated at an angle in the range of 30 to 70°, preferably ranging from 45 to 55°, with an interpillar spacing in the range of 1 to 10 μm in axial and lateral direction of the flow of the sample solution, preferably around 6 μm and 6.6 μm inter-pillar spacing in axial and lateral direction of the flow of the sample solution; c) a nanoparticle sorting and separation area being disposed downstream of the microparticle separation area and comprising nanochannels embedded with a deterministic lateral displacement array; said DLD array is achieved using 0.5 to 10 μm, preferably 2 μm and 1 μm, diameter pillars with 0.2 to 5 μm, preferably 1 μm and 500 nm, inter-pillar spacing; d) a functionalized nanoparticle trapping and detection area being disposed in the nanoparticle sorting and separation area and comprising a number of stages or steps (16a to 16c) that are patterned with different heights to trap different particles (18a to 18c) at different stage locations based on the particle size; said stages or steps (16a to 16c) preferably are supported with pillars to avoid pattern collapsing; and e) an out-port area for the waste sample solution.