Bioinspired Brochosomes as Broadband and Omnidirectional Surface-Enhanced Raman Scattering Substrates

Surface-enhanced Raman scattering (SERS) substrates capable of working under laser excitation in a broad wavelength range are highly desirable in diverse application fields. Here, we demonstrate that the bioinspired Ag brochosomes, hollow microscale particles with submicroscale pits, have broadband and omnidirectional SERS performance. The SERS performance of the Ag brochosomes under near-infrared laser excitation makes them promising for applications in biosensing fields, such as the sensitive detection of Staphylococcus aureus bacteria and bovine hemoglobin protein. Additionally, the SERS intensity was insensitive to the incident angle of the laser beam, resulting from the spherical structure of the Ag brochosomes. The omnidirectional SERS performance makes the Ag brochosomes have application potential for in-the-field analysis using a hand-held Raman spectrometer for which it is difficult to accurately control the laser beam normal to the SERS substrates. Overall, the broadband and omnidirectional brochosome SERS substrates will find applications in diverse fields, particularly in biomedicine and in-the-field analysis.