Metal-Amino Acid Nanocrystals Synthesis and Applications
Amino acid is a naturally occurring organic molecule can be mass-synthesized and has been manufactured commercially. As a basic unit of proteins, amino acid is nontoxic and can be absorbed in vivo, which has led to its application in many fields. Therefore, if amino acid molecules can be used as building blocks to combine with specific metal ions, the novel functional nanomaterials should have great applications in many fields.
Terbium-aspartic acid (Tb-Asp) nanocrystals with chirality-dependent tunable fluorescent properties can be synthesized through a facile synthesis method through the coordination between Tb and Asp. Asp with different chirality (dextrorotation/D and levogyration/L) changes the stability of coordination center following fluorescent absorption/emission ability difference. Compared with L-Asp, D-Asp can coordinate Tb to form more stable center, following the higher quantum yield and longer fluorescence life. Fluorescent intensity of Tb-Asp linearly increases with increase ratio of D-Asp in the mixed chirality Tb-Asp system, and the fluorescent properties of Tb-Asp nanocrystals can be tuned by adjusting the chirality ratio. Tb-Asp nanocrystals possess many advantages, such as high bio-compatibility, without any color in visible light irradiation, mono-dispersion with very small size, long fluorescent life. Those characteristics will bring its great potential in many application fields, such as low-cost anti-fake markers and advertisements using ink-jet printer or mold molding when dispersed in PDMS. In addition, europium (Eu) can also been used to synthesize Eu-Asp nanoparticles. Importantly, the facile, low cost, high yield and mass-productive “green” synthesis approach opens a new door for synthesis and application of the new generation fluorescent nanocrystals, which will have great impact in nanomaterial technology. (Baojin Ma, et al. ACS nano 11.2 (2017): 1973-1981)
Further, other metal-amino acid nanocrystals are being synthesized and will be applied in many fields according their unique properties. Through structure design and property optimization, it can be believed that the novel metal-amino acid nanocrystals with multi-functions will have very important and wide applications.