Egg white based biological microlasers

Biolasers made of biological materials hold great potential for implantable biosensing and cell-tracking. However, the current bio-extracted materials used for biolasers generally require a complicated synthesis process and therefore suffer from high cost. In this work, we demonstrate that low-cost natural egg white is an excellent biomaterial for a laser cavity. Using a simple dehydration method, dye-doped goose egg white microspheres are obtained with various sizes from 20 to 160 µm in diameter. These microspheres can act as excellent laser sources under optical excitation with lasing threshold of ∼26 µJ mm−2 and quality (Q) factor up to 3 × 103. The lasing mechanism is studied and ascribed to the whispering gallery mode. Size-dependence of the lasing spectrum and Q factor are also investigated. Owing to the ease of fabrication, the cost-effectiveness, goose egg white based microlasers are promising for biosensing and bioimaging applications.