To sum up

Pros

Gold nanoparticles can be easily prepared and functionalized, and they present significant potential for medical sciences, including antibacterial, antioxidant, an-tiparasitic, antiangiogenic potential, and anticancer properties. The functionalization of gold nanoparticles with flavonoid compounds improves their biological effects. These effects were presented for gold nanoparticles func-tionalized with chrysin, kaempferol, quercetin, epigallocatechin gallate, procya-nidins, 4′,7-dihydroxyflavone, metal-phenolic networks, and green tea polyphe-nols. Due to the photothermal effect, flavonoid-AuNP conjugates reveal significant potential for both antibacterial activity and wound healing. Depending on the conjugation between proper flavonoid and gold nanoparticles, diverse applicability of fabricated systems can be obtained—from antibacterial agents to biosensors. A gold nanocluster was also applied for sensitive and selec-tive detection of dopamine, whereas hesperidin isolated from orange peels was used in the synthesis of gold nanoparticles, which was applied both as an antiox-idant and a photocatalyst for the treatment of industrial wastewater. Despite using structurally diverse flavonoids, no influence on the maximum emis-sion wavelength or fluorescence lifetime of the gold nanoparticles was observed.

Cons

Limited information is known about the long-term toxicity of gold nanoparticles. Some organic functionalizations, such as citrate, might increase toxicity rather than decrease it [69]. Therefore, the toxicity of conjugates should be carefully evaluated. The strong positive potential of some reported herein nanoparticles might raise safety issues, as the feature was correlated with membrane damage [55]. In contrast to spherical nanoparticles, gold nanorods are reported to disturb pro-tein structures and reveal reduced mobility - they remain at the injection site, where they might cause damage [69]. The competitiveness of the currently developed systems is unclear as there is a lack of studies undertaking this topic. The glucose sensors based on flavonoids [68] still require optimization for better functioning, as commercially used systems are more advantageous [70].