efficient use of pumps requiring smaller cooling systems [2]. To obtain the NPs, two techniques are used, the one-step and two-step methods [1; 5; 8]. The one-step method combines NPs preparation and fluid synthesis, which tends to improve stability. The NPs are prepared by physical vapor deposition (carbon nanotubes) or by the chemical liquid method (Copper nanofluid) [8; 9; 10]. In the two-step method, NPs are first produced in processes such as dry powder by inert gas condensation (aluminum, copper, molybdenum, platinum, titanium, and iron oxides NPs) [11], mechanical alloying (Ni\({}_{3}\)S\({}_{2}\), Mg\({}_{2}\)Ti\({}_{4}\), CoFe\({}_{2}\)O\({}_{4}\)) [12; 13; 14], chemical vapor deposition (Boron nitride nanotubes, Carbon nanotubes, Fe\({}_{3}\)O\({}_{4}\)) [15; 16; 17], or chemical deposition (PbS) [18], and, after the appropriate separation and drying processes, are dispersed in the fluid [8; 19]. As the tendency of agglomeration is greater in this step, methods such as ultrasonic agitation and the addition of surfactants are used to improve the dispersion and thermal properties [8]. There are applications of nanofluids in various heat exchange systems for engines, solar panels, nuclear, and space areas, as well as their use in biomedical, machining, and energy storage [2].The greatest interest to use is the potential improvement in the heat transfer properties of current fluids. Due to the small size of NPs, NFs are easily compatible with systems that use common fluids and, therefore, can be applied in conventional heat exchangers such as tube type, car radiators, refrigeration systems (as in Vapour Compression Refrigeration System) (VCRS) which allowed a significant increase in COP [20]. Antibacterial properties of NPs embedded in NFs may also contribute to slowing down their deterioration and improving their heat and mass transfer rates, such as silver nanoparticles in a modified solar desalination system [20; 21]. NFs and NPs with thermoelectric effect allow the creation of electricity and thermal energy co-generators in solar light absorption systems. In this context, the optical properties of nanofluids can also open doors to the improvement of solar collectors [22]. NFs that use magnetic and dielectric NPs that are subject to electromagnetic waves allow changes in interfacial tension, changes in wettability and viscosity, and as a result makes this option a promising technology for crude oil extraction in porous media [23]. There are many areas of study in which nanofluids have been explored [24; 25]. In the field of machining, this technology has been used for coolants and lubricants for turning, milling, drilling, and other operations [26]. Many works explore the improvement of the Minimum Quantity Lubrication (MQL) method and its influence on thermophysical, tribological, and wetting properties of NFs for this type of application [27]. In solar energy, the use of nanofluids has been widely studied as a form to improve heat exchangers in solar collectors, as presented in the review by [PERSON] et al. [28], focused on hybrid nanofluids. [PERSON] et al. [29] used nanofluids as liquids for heat transfer in a parabolic collector achieving a significant increase in performance. [PERSON] et al. [30] and [PERSON] et al. [31] achieved significant improvements in solar still. [PERSON] et al. [32] increased the output power and energy efficiency of a solar cooker. [PERSON] and [PERSON] [33] increased not only the heat transfer but also the required pump power and the efficiency of a photovoltaic cell cooling system. NFs can be useful in biomedicine/medicine in processes such as magnetic separation, bioassays, drug and therapeutic administration, cancer treatments, aid in diagnosis, and estimate mechanical and rheological properties of cells [34; 35; 36]. This work has as main objective to present a review of the main properties and applications of NFs in three main areas: machining, solar energy, and biomedical.