# Biosynthesis of Zinc Oxide Nanoparticles Using Seaweed: Exploring Their Therapeutic Potentials
## 4 Discussion  
Due to its advantages over conventional chemical synthesis processes regarding expenses and effects on the environment, green nanomaterials have attracted significant attention. One of the well-known metal oxide nanoparticles with considerable applicability in numerous sectors is zinc oxide nanoparticles (ZnO-NPs) [34]. The visual change as a white precipitate was initially used to pinpoint the biosynthesis of ZnO-NPs. The findings demonstrated that zinc acetate (Zn (CH\({}_{3}\)CO\({}_{2}\)))\({}_{2}\) and seaweed crude extract from _U. lactuca_, _S. maticum_, and _U. intestinalis_ effectively reacted to create ZnO-NPs via a reduction process within 2 h using a magnetic stirrer [35]. It was found that the biosynthesised ZnO-NPs' surface plasmon band has a wavelength of between 310 and 360 nm. In the present study, the formation of ZnO-NPs  
Figure 10: Microscopic pictures of H&E-stained, untreated Ehrlich ascites tumors (EAC) and the treated groups. (**A**) Ehrlich acetic carcinoma, (**B**) doxorubicin, (**C**) ZnO-NPs biosynthesized using _Ulva lactuca_ extract. Low magnification 100\(\times\): bar 100; higher magnification 400\(\times\): bar 50.  
synthesized using _U. lactuca_, _S. muticum_, and _U. intestinalis_ was confirmed based on the UV-Vis spectrum, which showed emission peaks at 374, 375, and 376 nm, respectively. According to ref. [36], because the ZnO nanoparticles are situated significantly below the band gap wavelength of 358 nm, the produced ZnO nanopowder's absorption spectra exhibited a strong absorption band at around 355 nm and an excitonic absorption peak at about 258 nm. Additionally, ref. [37] observed that ZnO-NPs displayed high UV absorption bands at 265 and 390 nm, indicating the synthesis of ZnO-NPs. According to various recent studies, the existence of bands between 230 and 390 nm is a sign of the development of ZnO-NPs [38]. The functional group that is in charge of reduction and serves as a capping agent in biosynthetic nanoparticles can be identified and characterized using an important technique known as FTIR [39]. In this study, the FTIR analysis confirmed the reduction of metal ions and determined the potential biomolecules in charge of the effective stability and capping of the metal nanoparticles formed by the seaweeds extracts. Similar studies have demonstrated that metal oxides exhibit absorption bands originating from interatomic vibrations in the fingerprint regions below 1000 cm\({}^{-1}\)[40]. In order to reduce, cap, and stabilize biosynthesized ZnO-NPs, ref. [41] conducted an FTIR investigation using _Ericaria cinita_ (formerly _Cystoseira cinita_) (Phaeophyceaeae) extract. They found that phenolic chemicals and proteins play a role in this process. By passing X-rays through a pattern that produces nanoparticles, the XRD technique determines the size and shape of materials [38]. In the present study, ZnO-NPs were formed by seaweeds with Bragg angles corresponding to zinc 20 = 102. The XRD research indicated that the ZnO nanoparticles had a wurtzite structure, and the emergence of a narrow peak with a Bragg's angle of 2 = 102 suggests that the ZnO nanoparticles were crystalline. The ZnO-NPs produced using _E. cinita_ were subjected to XRD analysis, which revealed distinctive peaks at values of 31.78, 34.42, 36.26, 47.6, 56.6, and 62. Ref. [41] attributed these values to the (100), (002), (101), (102), (110), (103), and (112) planes, respectively. The current findings were consistent with many studies that reported XRD patterns of phyco-synthesized ZnO-NPs that were similar to the present results [11; 42]. A transmission electron microscopy (TEM) analysis was used to determine the size and morphological characteristics of the generated ZnO-NPs. In this study, ZnO-NPs were determined based on the TEM image within a size range of approximately 4.13 to 8.56 nm, with a mean particle size estimated to be 5.6 nm for the ZnO-NPs formed using the _U. lactuca_ extract. The size of the ZnO-NPs formed using the _S.