A novel quantum dot containing two different metals at non-toxic levels which is capable of narrow bandwidth near infrared emissions at wavelengths of 600-1100 nm. The quantum dot is fabricated via an aqueous method which forms a structure having an inner region of one composition and an outer region of a different composition, wherein the inner region contains at least a first metal and the outer region contains at least a second metal. The quantum dots may be enabled for bioconjugation and may be used in a method for tissue imaging and analyte detection.