Shape effect on the fabrication of imprinted nanoparticles: Comparison between spherical-, rod-, hexagonal-, and flower-shaped nanoparticles

- Different shaped (spherical, rod, hexagonal, flower) AgNPs were prepared by green-chemistry.
- AgNPs were modified with 2-bromoisobutyl bromide and used as nanoinitiator.
- Effect of different shaped-AgNPs on the performance of MIP was studied.
- Among the different formats, the flower shaped AgNPs@MIPs win the race.
- Shape-specific MIPs was developed for selective detection of phenformin in real samples.

In this work, we prepared four different shaped silver nanoparticles (AgNPs) (spherical, rod, hexagonal, and flower shaped) by using the green synthesis approach. The synthesized AgNPs were characterized by UV-vis spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, which showed that AgNPs have a very narrow size distribution with visible and confined geometry and shape. The synthesized AgNPs were modified by 2-bromoisobutyryl bromide, developed as a nanoinitiator, and then used for the synthesis of phenformin-imprinted polymers (MIP@AgNPs). A comparative study was performed between different shaped MIP-modified AgNPs; in addition, the effect of AgNPs on electrocatalytic activity, surface area, adsorption capacity, and electrochemical and photoluminescence sensing of phenformin was also explored. Among the different shaped MIP@AgNPs, the anisotropic AgNPs have multiple facets and planes, i.e., the flower-shaped AgNPs showed the best performance and were successfully applied for trace-level detection of phenformin in an aqueous sample. Furthermore, the MIP@AgNPs were also applied for the detection of phenformin in human serum, plasma, and urine samples without any cross-reactivity effect, suggesting a bright prospect for the use of anisotropic nanomaterials in future clinical trials.

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