Picosecond Laser Fabrication of Functional Gold–Antibody Nanoconjugates for Biomedical Applications

Abstract

Conventional fabrication of gold nanoconjugates is often accomplished by multistep chemical synthesis, causing rather long production times (hours to days) and requiring multiple purification steps. In contrast, by applying femtosecond-laser systems the process of pulsed laser ablation in liquids (PLAL) with in situ bioconjugation may be used alternatively to produce surfactant-free and functional nanoconjugates within a single-step approach on the time scale of minutes. Gold nanoconjugates functionalized with nucleic acids, peptides, proteins, and aptamers were successfully established by these means. However, limited process productivity is a main disadvantage of the femtosecond-PLAL approach due to the short pulse duration. In this work for the first time, we utilize picosecond-PLAL to fabricate novel gold–antibody nanoconjugates for cellular staining issues. The functionality of the nanoconjugates is confirmed by blotting and cellular immunolabeling, resulting in equivalent staining results than achieved with conventional labeling markers. By the adoption of picosecond pulse duration a higher productivity by 1 order of magnitude is reached compared to the conventional femtosecond-PLAL. Moreover, the production of nanoparticles and nanoconjugates with the same surface composition, the same amount of biomolecule load and the same level of biomolecule structure integrity is proven than that gained by femtosecond-PLAL. Finally, the potential physical mechanisms of biomolecule degradation and the quantitative online monitoring of the degradation are discussed. The results emphasize laser-fabricated gold–antibody nanoconjugates as competing products to commercial immunoflow or cellular staining markers. Moreover, picosecond-PLAL enables a significantly higher production speed of gold nanobiohybrids than that achieved via existing fabrication methods and therefore represents a competing technology.