The invention described herein provides methods for the detection of soluble antigens. In particular, the methods provide for the detection of soluble proteins and chemicals. In addition, the invention provides methods of detecting a nucleic acid sequence in a sample. Also described is an emittor cell comprising an Fc receptor and an emittor molecule for the detection of a target particle in a sample wherein the target particle to be detected is bound by one or more antibodies. Also provided is an optoelectronic sensor device for detecting a target particle in a plurality of samples.