Abstract: A method and device for detecting the presence of an unbound portion of therapeutic agents in a bodily fluid sample provided in which the bodily fluid includes an endogenous component of geometrical size larger than the therapeutic agent. A photonic integrated circuit has a porous material enrichment layer, a waveguide formed in the enrichment layer, and a blocking means provided on an outer surface of the enrichment layer. The enrichment layer with blocking means is permeable to the unbound therapeutic agent and prevents penetration of the endogenous component into pores of enrichment layer. The blocking means is configured to cooperate with the enrichment layer to maintain therapeutic agent access to the pores of the enrichment layer and prevent light-matter interaction between the at least one endogenous component and light guided in the waveguide, when contacting the liquid sample with the photonic integrated circuit.

Abstract: The present disclosure relates to the field of biochemistry, more particularly to detecting and measuring enzyme activity, even more particularly to detecting and measuring protease or nuclease activity. The means and methods disclosed in this application make use of Raman scattering, more particularly of surface enhanced Raman scattering (SERS). The disclosure discloses a carrier on which a monolayer of sequences containing a specific cleavage site is bound. The sequences comprise at least 2 Raman scatterers, one before and one behind the cleavage site, thereby providing an inherent control against ligand exchange.