Biophotonic sensors with integrated Si_(3)N_(4)-organic hybrid (SiNOH) lasers for point-of-care diagnostics

Early and efficient disease diagnosis with low-cost point-of-care devices is gaining importance for personalized medicine and public health protection.Within this context,waveguide-(WG)-based optical biosensors on the siliconnitride(Si_(3)N_(4))platform represent a particularly promising option,offering highly sensitive detection of indicative biomarkers in multiplexed sensor arrays operated by light in the visible-wavelength range.However,while passive Si_(3)N_(4)-based photonic circuits lend themselves to highly scalable mass production,the integration of low-cost light sources remains a challenge.In this paper,we demonstrate optical biosensors that combine Si_(3)N_(4)sensor circuits with hybrid on-chip organic lasers.These Si_(3)N_(4)-organic hybrid(SiNOH)lasers rely on a dye-doped cladding material that are deposited on top of a passive WG and that are optically pumped by an external light source.Fabrication of the devices is simple:The underlying Si_(3)N_(4)WGs are structured in a single lithography step,and the organic gain medium is subsequently applied by dispensing,spin-coating,or ink-jet printing processes.A highly parallel read-out of the optical sensor signals is accomplished with a simple camera.In our proof-of-concept experiment,we demonstrate the viability of the approach by detecting different concentrations of fibrinogen in phosphate-buffered saline solutions with a sensor-length(L-)-related sensitivity of S/L=0.16 rad nM^(-1)mm^(-1).To our knowledge,this is the first demonstration of an integrated optical circuit driven by a co-integrated low-cost organic light source.We expect that the versatility of the device concept,the simple operation principle,and the compatibility with cost-efficient mass production will make the concept a highly attractive option for applications in biophotonics and point-of-care diagnostics.