Single molecule detection is one of the main challenges in biosensing. Plasmonic antennas are often used to enhance the optical signals and nano-focus the light beyond diffraction - but bringing the target element into the hot spot is still a major difficulty. We integrate nano channels with nano-optics (e.g., plasmonic components) for in-line, real time analysis of liquid flow, of biomolecules and particles. We will show the use of the devices for DNA single molecule optical mapping for biomedical applications. For example, for studying the DNA of viruses, of cancerous cells, or for quantitative analysis of circulating tumor DNA.