Biosynthesis and adhesion of gold nanoparticles for breast cancer detection and treatment

Gold nanoparticles (AuNPs) were biosynthesized using Bacillus megaterium, a common soil bacterium. Transmission electron microscopy images revealed that well-developed, spherical, homogeneous nanoparticles are formed extracellularly in reactions containing aqueous chloroaurate ions and conditioned medium at pH 4. Atomic force microscopy measurements showed that adhesion forces between biosynthesized AuNPs and breast cancer cells were almost six times greater than adhesion forces between biosynthesized AuNPs and normal breast cells. Furthermore, adhesion forces of biosynthesized AuNPs to breast cancer cells were three times greater than adhesion forces between chemically synthesized AuNPs and the same breast cancer cells. Finally, adhesion forces between biosynthesized AuNPs conjugated to breast-specific antibodies (AuNP-Ab conjugates), and breast cancer cells were almost five times greater than adhesion forces between unconjugated AuNPs and breast cancer cells. The implications of the results are discussed for the development of nanostructures for the targeted detection and treatment of breast cancer.