## 4 Drug Delivery Applications  
Y\({}_{2}\)O\({}_{3}\) physiochemical properties have also been used in several biomedicine applications and utilized as potential drug delivery vehicles. This application targeted at cancer cells has shown to be a combined anticancer effect, due to its cytotoxic ability towards cancer cells. Many researchers studied Y\({}_{2}\)O\({}_{3}\) NPs using drug delivery methods. [PERSON] et al. [110] have synthesized similar-sized NPs derived from melamine-formaldehyde (MF) templates, followed by calcination, and counted crystalline Y\({}_{2}\)O\({}_{3}\) precursors to Y\({}_{2}\)O\({}_{3}\) NPs during the annealing process. The shell of hollow nanospheres was filled with numerous NPs of a similar size. Moreover, a lanthanide activator Ln\({}^{3+}\) doped with Y\({}_{2}\)O\({}_{3}\) NPs was synthesized, and such NPs were found to be bright and sensitive to up-and-down-conversion of luminescence ability with a diverse color source. The nanoparticles have proved to be an effective drug vehicle for cancer-related diseases. Another study conducted by [PERSON] et al. [111] has recently reported that yttrium oxide fluorescence and magnetic, bifunctional nanoparticles have shown an unmatched application, including nano drugs. Their findings demonstrated bifunctional hollow microsphere (BHMs) hollow core structures that were designed and loaded with biofrotus drugs. This was examined in preclinical research, and showed that BHMs executed appreciable drug delivery and loaded capacity (126 mg/g). Moreover, a prolonged time of drug release was also observed. This ability provides insight into employing these Y\({}_{2}\)O\({}_{3}\) NPs as drug carriers targeting cancer cell therapy.  
Microscopic particles are great to deal with the increasing interest in the cytotoxicity of NPs [112]; few researchers have studied the responses of nerve cells exposed to NPs. However, there are limited studies to examine the biological consequences of synthetic nanoparticles. [PERSON] et al. [113] determined the cytotoxicity of a group of NPs on the well-recognized cell line of murine macrophages and showed that a diverse group of NPs is cytotoxic. [PERSON] et al. have reported that Y\({}_{2}\)O\({}_{3}\) NPs have shown the rescue role of nerve cells from oxidative stress in HT22 cells [109]. Neuroprotection is associated with the size of the NPs. The study revealed that Y\({}_{2}\)O\({}_{3}\) NPs served as a direct antioxidant, and blockaded the ROS production. The mode of action was stimulated by reducing the level of ROS production that speeds up and activates ROS defense mechanism, prior to glutamate-induced apoptosis being complete. This occurred while exposure of cells to the NPs reportedly stimulated a low level of ROS [114]. ROS in the best way to predict direct antioxidants in intact cells [115]. Y\({}_{2}\)O\({}_{3}\) NPs are able to curtail the pools of generated ROS non-NPs oxides or salts that are not protective that indicated size and structure determinations for the antioxidant efficiency of NPs. However, it has been reported that the neuroprotective response purely depends upon the physiochemical and characteristics of exposed nanoparticles and their size. They demonstrated Y\({}_{2}\)O\({}_{3}\) NPs showed more potent antioxidants than CeO\({}_{2}\). Thus, it can be concluded that NPs of Y\({}_{2}\)O\({}_{3}\) can help the survival of nerve cells under oxidative stress, which could be used for therapeutic applications.