Sodium hexametaphosphate–induced enhancement of silver nanoparticle toxicity towards leukemia cells

Abstract

Synergistic effects occurring between biologically active substances are of great importance for efficient treatment of many diseases. Therefore, the aim of research was to determine impact of sodium hexametaphosphate (HEX), which is a well-known permeabilizer, on the cytotoxicity of silver ions and two types of AgNPs towards HL-60 and U-937 tumor cells. The AgNPs were synthesized in a chemical reduction method using sodium borohydride and trisodium citrate (CITAgNPS) or sodium hypophosphite and HEX (HEXAgNPs). Imaging with the use of transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed that the AgNPs exhibited spherical shape and comparable size distribution. Electrophoretic mobility studies showed that the AgNPs were negatively charged. The mitochondrial and antioxidant activity as well as membrane lipid peroxidation and integrity after dose-dependent AgNP treatment were evaluated using biochemical assays. The impact of HEXAgNPs on the membrane integrity and inactivation of antioxidant enzymes of the cells was much higher than this one observed for CITAgNPs and silver ions of the same concentration. The membrane damage occurred as a result of lipid peroxidation which was induced by pure HEX and HEXAgNPs. It was also observed that HEX significantly increased cell membrane damage induced by CITAgNPs and silver ions although the cells exhibited different sensitivity to these components. Moreover, it was found that HEX can induce oxidative stress. Hence, it was revealed that HEX enhances AgNP activity when it is applied both as their stabilizer or supplement in their suspensions.

Antibacterial and Antifungal Properties of Silver Nanoparticles—Effect of a Surface-Stabilizing Agent

“…Sodium hypophosphite (SH) is barely known as a reagent used in the preparation of MeNPs. Nevertheless, it was proven that its combination with sodium hexametaphosphate (SH) allows for the production of stable AgNPs of enhanced biocidal activity [33,52].…”

“…The combination of sodium hypophosphite (SH) and sodium hexametaphosphate (SH) is not often used in the preparation of MeNPs. Nevertheless, it was proven that in this system, sodium hypophosphite (SH) reduces silver ions [66] and sodium hexametaphosphate (SH) plays the role of a stabilizing agent [33].…”

“…Based on this literature, one can conclude that chemicals used as reducing and stabilizing agents of AgNPs are major factors modeling biological activity [16]. The impact of reducing and stabilizing agents on AgNP toxicity can be indirect, e.g., if they amplify silver ion release [32] or intensify the penetration of AgNPs through biological membranes [33]. On the other hand, stabilizing agents adsorbed on the surfaces of AgNPs can also act directly on cells and microorganisms.…”

“…On the other hand, stabilizing agents adsorbed on the surfaces of AgNPs can also act directly on cells and microorganisms. Hence, the use of AgNP-stabilizing agents exhibiting biocidal properties can create synergistic effects and enhance the toxicity of silver [33,34]. Nowadays, the attention of scientists is focused on the development of methods of preparation of AgNPs characterized by controlled activity towards pathogens [35] and tumor cells [36].…”

Design cytotoxicity: The effect of silver nanoparticles stabilized by selected antioxidants on melanoma cells

“…It is worth mentioning that AgNPs seem to be promising candidates for cancer treatment. Their antiproliferative properties toward, for example, human glioblastoma (U251) (Asharani, Hande, & Valiyaveettil, 2009), breast (MCF‐7), lung (A549) (El‐Hussein et al, 2015), prostate (PC‐3) (He et al, 2016), and leukemia (HL‐60, U‐937) (Oćwieja & Barbasz, 2020) cancer cells have been demonstrated.…”