**5. Conclusions**

*Microemulsion - A Chemical Nanoreactor*

ment depending on the solvent nature [34].

detect and treat cancer.

APTMS. The mixture was stirred using a mini-stir bar (200 r.p.m., during 12 h) at room temperature to acquire the APTMS-coated C60S, C60S-A NPs. Lastly, the sample of C60S-A NPs was merged with DPPC liposomes and shacked for 5 h (r.t.) to harvest the phospholipid bilayer-coated C60S, LC60S-NPs. The LC60S NPs were gathered by centrifuging at 13,800 × g for 10 min. The DPPC liposomes were prepared by hydrating a thin DPPC film. Subsequently sonication for 2 min using a Branson 450 Sonifier, the sample of DPPC (1,2-dihexadecanoyl- sn-glycero-3-phosphocholine) liposomes (≈100 nm) was filtered throughout a 0.2 mm filter earlier mixing with the solution of C60S-A nanoparticles. I carried out a research on re-dispersion and self-assembly of C60 pointed special performance and arrange-

Authors concluded that both the encapsulation efficiency (EE) and minimal drug loading content (LC) of theranostic agents are vital calibers of multifunctional NPs for drug transfer. To attain great EE, low drug-to-NP provision ratios have frequently been applied for encapsulation, which outcomes in low drug LC. Authors designed a eukaryotic cell-like nanoplatform or EukaCell, which can be applied to attain great EE (≈100%) and LC (up to ≈87%) of theranostic agents (DOX and ICG). The release of the encapsulated drug can be exactly controlled using NIR laser irradiation to minimize the potential side effects. With the biomimetic eukaryotic cell-like configuration, the EukaCell had an extended half-life and strong stability in blood circulation and could favorably accumulate in tumor following intravenous injection. Finally, the drug-laden EukaCell displayed excellent safety and efficacy for cancer therapy. Authors demonstrated the tremendous potential of their EukaCell for providing theranostic agents to

Tianimoghadam and Salabat reported the formulation of new microemulsion to prepare thiol-functionalized AuNPs [35]. The microemulsion system was obtained by mixing a yellow aqueous solution of 0.03 M of HAuCl4 and a 0.05 M solution of TOAB/toluene. The same microemulsion containing 0.4 M of NaBH4 was prepared independently and drop-wised under energetic stirring into the microemulsion enclosing metal ions. The formation of AuNPs was confirmed by the appearance of a stable light-ruby-red color resulting in microemulsion when the reduced Au(III) ions changed. To form a thiol monolayer surrounding the AuNPs, dodecanethiol (17 mg) was added while kept stirring during 1 h. To eliminate all residual TOAB surfactants (see TOAB chemical structure in **Figure 10**) and thiols from the AuNP surfaces, the AuNPs were pipetted into a 10 mL vial along with 3 mL ethanol and then centrifuged. This procedure was sixfold repeated, after which the dodecanethiol-stabilized AuNPs were then resuspended in toluene. The stable nanocolloid system of Au/toluene was then prepared for characterization. To confirm the size distribution and formation of the AuNPs, TEM techniques and UV-Vis absorption were used. The absorption maximum was found to be 524 nm, which is a shift typical for spherical AuNPs. This surface plasmon band agrees to 3–4 nm particles. According to the Mie theory, the purification procedure removed the

**86**

**Figure 10.**

*TOAB chemical structure.*

As this review chapter has stated, microemulsion method must be taken into account when the aim of the researcher is to prepare well-controlled, narrow-sized, monodispersed NPs.

The influence of microemulsion components has been reviewed; not only the ratio between aqueous phase/surfactant and surfactant/metal precursor but also the influence of the nature of the surfactant—ionic, cationic, and nonionic surfactants—will offer different self-assembled systems. It was underlined that hydrodynamic radius (*rW* = 1.5 *W*) of the microdroplets that forms the microemulsion essentially depends on *W* = [water/surfactant] so the size of our template will be defined by this relation and microdroplet will offer a well-defined microenvironment to prepare NPs. The influence of the tensioactive nature was also considered by the interaction with metal precursors, co-surfactant, during the nucleation and growth processes and consequent influence upon surficial charge of the NPs. Thus the influence of the reagents and its proportions or ratio will determine the size of water pool within the microdroplets, which finally determine size, shape, morphology, and crystalline structure of the NPs. The control of the reaction time, the temperature, and reagent nature and ratios between them will give us a production of different geometries that will find different applications in wide range of research fields, such as chemical sensors, CO sensing, applications on drug delivery and theranostic, quantum dots, MRI, and biomedicine. It can be concluded that microemulsion method actually offers a good route for synthesis of NPs.

### **Acknowledgements**

Dr. A. Cid acknowledges the postdoctoral contract granted to CIA research group by FEDER Funds at Physical Chemistry Department Universidade de Vigo and the Unidade de Ciências Biomoleculares Aplicadas-UCIBIO which is financed by national funds from FCT/MEC (UID/Multi/04378/2013) and cofinanced by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145- FEDER-007728). This chapter is dedicated to Professor Julio Casado Linarejos, who was a great support during my formation as scientist.

### **Conflict of interest**

Author does not declare conflict of interest.
