Abstract: The present invention is directed to methods of manufacture of microfluidic chip such as a plastic microfluidic chips, which has channels packed with polymer-embedded particles and uses thereof. The chip of the present invention is designed for application of an untreated biological sample on the chip thus allowing isolation, purification and detection of biomolecules, such as nucleic acids, proteins or peptides in one step. The invention also provides a microfluidic chip for combined isolation, purification and detection of biomolecules thus providing a complete Lab-on-a-Chip analysis system for biomolecules such as nucleic acids and proteins. The chips of the invention can be adapted to perform highly specific immunoassays and diagnostic test, for example, for diagnosis of infectious agents, such as bacteria, viruses or parasites.