The in vitro delivery of Doxorubicin using biosynthesized versus chemically synthesized stealth site-specific Bimetallic Selenium-silver nanoparticles
Authors:   , Malinga Thoko Winnie 
Published: June 2023

Problems related to the limitations of chemotherapeutic treatments compel the pressing necessity to develop a drug-delivery system that will specifically target tumor cells and have minimal or no harmful effects on normal/healthy cells. This study aimed to comparatively evaluate the ability of chemically versus biologically synthesized site-specific selenium-silver bimetallic stabilized folic targeted nanoparticles (SeAgChPEGFA NPs) to efficiently deliver doxorubicin (DOX) in cervical cancer cells (HeLa). The NPs were synthesized using a coreduction method chemically using sodium borohydride and polyvinylpyrrolidone, and biologically using fenugreek seed extract. Moreover, the NPs from both methods of synthesis were stabilized and functionalized using carbodiimide and adsorptionreaction procedures. The drug/DOX-loaded nanocomplexes (NCs) were prepared via anadsorption and amide bonding reaction process between the co-polymer stabilized NPs and DOX. The bimetallic NPs and their DOX-loaded NCs were characterized using ultraviolet- visible (UV-vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and zeta Sizer. The drug release, loading, and encapsulation capabilities were evaluated in an in vitro environment. The effects of the synthesized NCs on cell viability and programmed cell death analysis were evaluated by means of the 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay and a dual staining technique in selected human non-cancer and cancer cell lines (HEK293 and HeLa cells), respectively. The NPs and their drug-loaded NCs were successfully formulated and characterized. The successful synthesis of the NPs was initially validated by the reaction mixtures’ change in colour from cloudy to red-orange and subsequently from yellow-gold to orange-brown, signifying the formation of SeAg NPs and F-SeAg NPs, respectively. The UV- spectroscopy revealed that the SeAg NPs absorbance peaks were between 260 nm and 320 nm, while the FTIR verified the stabilization and functionalization of the NPs by revealing the presence of carbodiimide and amide bonds. All the resultant NPs and their drug-loaded NCs were shown asspherical withthe NPs appearing predominantly monodispersed and the NCs as groups. The sizes of the chemically and biosynthesized NPs ranged between 103.5 nm and 138.8 nm and that of the DOX-loaded NCs ranged between 154.9 nm and 158.7 nm respectively. The DOXloaded chemically- and biologically-synthesized NCs showed good stability with zeta measurements of 53.1 ± 2.3 mV and 57.4 ± 1.9 mV, respectively. The encapsulation efficiency (EE%) and drug loading (DL%) percentages of the chemically synthesized NCs were calculated to be 84% and 26%, respectively, while the percentages of the biosynthesized NCs were 87% and 22%, respectively. The cytotoxicity and anticancer activities of the BMNPs/NCsfrom both methods of synthesis were cell-specific and concentration-dependent. Overall, the encapsulation of DOX to the eco-friendly formulated BNPs enhanced the biocompatibility, bioavailability, and therapeutic effects ofthe drug in tumor cells, with limited harm to the healthy cells, thus showing promise as alternative delivery systems for targeted cancer treatment. The findings indicated that both the chemically synthesized and biosynthesized NPs showed great potential as anticancer drug-delivery modalities, with the biosynthesized SeAgChPEGFA@DOX NCs showing superior optical, surface charge stability, and drug encapsulation properties than the chemically synthesized SeAgChPEGFA@DOX NCs and free DOX. Moreover, among the studied synthesis methods, biosynthesis is reported to be eco-friendly and as a result the more ideal anticancer drug-delivery system with favourable features forfuture in vivo applications. Thus, future studies can encompass in vivo assessment of this eco-friendly system to further evaluate at a broader scale the bimetallic system’s efficacy and safety before using these NPs clinically.