Applications of Gold Nanoparticles in Nanomedicine: Recent Advances in Vaccines †

Carabineiro, Sónia Alexandra Correia

It is well known that gold is inert in the bulk stable and is only active as a catalyst in the form of nanoparticles [1] [2] [3] [4] [5] [6] [7] . As the name suggests, nanoparticles have small (nano) size and corresponding large surface/volume ratio. Examples are shown in Figure 1 . Due to these characteristics, Au nanoparticles can have an important role, not only in catalysis, but also in nanomedicine, suitable for several biological applications. In fact, it has been argued that Au nanoparticles could be used in almost all medical applications, from diagnostics to therapy, prevention, and hygiene [8] [9] [10] [11] [12] [13] [14] . Gold nanoparticles have remarkable properties and can also play an important role in vaccine research for several diseases, as showed in several recent reviews [8, 9, [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] . Vaccines have been a significant advancement in public health, preventing the death of many millions of people every year [31] . The main purpose of vaccination is to introduce an antigen from a Vaccines have been a significant advancement in public health, preventing the death of many millions of people every year [31] . The main purpose of vaccination is to introduce an antigen from Usually nanoparticles are synthesized in colloidal solution by reduction of chloroauric acid (HAuCl4) by variations of the so-called Turkevich method [46] . Their characterization is carried out by ultraviolet-visible spectroscopy, their diameters determined by transmission electron microscopy. Then, they can be further functionalized with the desired molecules, according to their specific needs. One example is given in Scheme 1, showing a procedure carried out by Saha et al. [47] . Gold nanoparticles were synthesized in aqueous medium by an ultra-sound assisted green method using black pepper extract and chitosan as reducing agent and a stabilizing agent, respectively. The biopolymer-inspired biogenic method (Scheme 1) was found to be stable and with enhanced bioactivity. The developed nanomaterial boosts the production of reactive oxygen species and misbalances the antioxidant parameters of detoxification enzymes of filarial parasites, such as GST, which besides its immune prophylactic potency, is also a promising candidate vaccine as shown in S. cervi and W. Bancrofti [47] .