Supramolecular Structures as Carrier Systems Enabling the Use of Metal Ions in Antibacterial Therapy

Abstract

The antimicrobial activity of metal ions, especially silver ions, has been known since ancient times. Consequently, finding an accessible, cheap and efficient carrier of metal ions remains an important challenge in molecular biology. The supramolecular system presented in this chapter consists of a mixture of Congo red and Titan yellow molecules forming a supramolecular ligand which is a potent complexing agent of silver ions. Delivery of ions in complex with supramolecular dye is advantageous due to the reduced toxicity. In addition, the use of Congo red provides selective action and -thanks to increased solubility -facilitates efficient dispersion of the carrier dye and excretion from the organism.

Antibacterial Therapy by Ag+ Ions Complexed with Titan Yellow/Congo Red and Albumin during Anticancer Therapy of Urinary Bladder Cancer

“…Our preliminary results for TY-Ag on human U937 lymphoid cell line cells confirm the efficacy of Ag + complexed at 9.8 µg/mL. Late apoptosis (73.65% of cells) and necrosis (about 25% of cells) were demonstrated after 72 h, after using TY-Ag 1:0.8 (where concentration of TY was 0.072 mM and concentration of Ag + was 0.057 mM [15]. Zhou et al described apoptosis of T24 cells induced by 48 h exposure to silver complexed in the Ag-SP-DNC complex (20 µM) at the level of 28.72% (early and late apoptosis together) [80].…”

“…The effect of TY-Ag or BSA-TY-Ag complexes on T24 cell proliferation (MTS), migration (scratch test) as well as viability/survival, and apoptosis induction (Caspase 3 assay–Cas 3, Flow cytometry) was assessed. The preliminary results obtained by us earlier on human U937 lymphoid cell line in which late apoptosis (73.65% of cells) and necrosis (about 25% of cells) was observed after 72 h, after using TY-Ag 1:0.8 (where the concentration of TY was 0.072 mM and concentration of Ag + was 0.057 mM [ 15 ] provided the basis for the analysis of the effect of these agents on bladder cancer cells.…”

“…Its halves are linked by a tri-azo bond capable of complexing metal ions, particularly silver and mercury. The silver-containing complex is more convenient due to its stability and formation in both neutral and slightly alkaline environments [ 15 , 55 , 56 ]. Thanks to this binding, Ag + becomes better available both for bacteria to fight them and for bladder cancer cells.…”

“…Such silver complexing compounds include Titan yellow, which we have recently analyzed, and its combination with albumin. The reactivity of such complexed silver is increased (the dissociation constant of the complex is estimated at 10 −13 ) because anions with Kd < 10 −13 do not remove silver from the complex [ 15 ]. Thanks to this, a lower concentration of silver can be used, which significantly reduces its toxicity and additionally provides protection.…”

“…The TY-Ag and CR-TY-Ag nano complexes have been partially described in [ 15 ]. On the other hand, the BSA-TY-Ag complexes have not been described in detail so far.…”