Improving Metal Adsorption on Triethylenetetramine (TETA) Functionalized SBA‐15 Mesoporous Silica Using Potentiometry, EPR and ssNMR

Abstract

Nanomaterials are receiving high attention in the treatment and diagnosis [3] of neurological disorders where the classical pharmacological approach is not effective due to low blood brain barrier (BBB) permeability. An effective drug delivery method is combining of drugs with nanocarriers, for example, polymeric micelles, liposomes, lipid, and polymeric nanoparticles (NPs), that have high BBB affinities. [4] Metal ion chelators, which are bound covalently to nanoparticles, can facilitate drug entry into the brain. [5] Desferrioxamine (Desferal) is an iron (Fe), aluminum (Al), copper (Cu), and zinc (Zn) chelator that showed a decrease of AD progression in clinical trials, [2,6] even if the low BBB permeability of DFO is still debatable. [7] DFO conjugated to polystyrene NPs of 240 nm and examined in human cortical neurons in vitro prevented Aβ peptide aggregation, [8] the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. [9] Nevertheless, low bioavailability and high toxicity restrict the use of metal chelators in humans. Functional nanoparticles are characterized by multiple incorporation of positron emitting radionuclides and signal enhancement in positron emission tomography (PET). [10] It has been Nanomaterials have received growing attention in the treatment and diagnosis of neurological disorders because the low blood brain barrier permeability hinders the classical pharmacological approach. Metal ion chelators combined with nanoparticles prove effective in the treatment of neurodegeneration and are under extensive studies. Most chelating agents and metallodrugs compete with endogenous molecules for metal coordination, and do not reach the active site. Determining the competition between metallodrugs and endogenous molecules requires knowing the stability constants of formed metal complexes. In this study, for the first time, potentiometric titrations are used to determine metal complex formation constants, and to quantify ligand content in functionalized materials. This new potentiometric approach allows physico-chemical characterization of mesoporous functionalized materials and their metal adsorption capacity in water solution. The potentiometric results are compared with isotherm models obtained by spectroscopic measurements and yield rewarding data fitting. The potentiometric method described here can be extended to different types of nanostructured materials carrying surface ionizable groups.

Metal Complex Formation and Anticancer Activity of Cu(I) and Cu(II) Complexes with Metformin

“…Protonation and complex-formation equilibrium studies were carried out under the same conditions described in previous publications [ 30 , 31 ]. The operating ligand concentrations ranged from 5 × 10 −4 to 4 × 10 −3 M. Complex formation studies were carried out using constant ligand concentration, and 1:1, 1:2, and 1:3 metal/ligand molar ratios.…”

Adsorption and Release of Sulfamethizole from Mesoporous Silica Nanoparticles Functionalised with Triethylenetetramine

“…CTAB extraction was carried out by suspending 3 g of product in 1 L of a EtOH/H 2 O (95:5 v / v ) solution containing NH 4 NO 3 10 g L −1 , kept for 2 h at 80 °C. TETA functionalisation was conducted by a method similar to that reported in the literature for other silica materials [ 71 ]. Briefly, 0.7 mL of CPTMS was added to 1 g of MSN suspended in 25 mL of anhydrous toluene.…”

Functionalised electrospun membranes (TETA-PVC) for the removal of lead(ii) from water

“…1 based on the literature. 41 Moreover, XPS analyses proved the formation of covalent bonds between NH 2 in TETA and lead( ii ) ions in water. 44…”

“…Polyvinyl chloride (PVC) was employed for the fabrication of the membrane and the resulting PVC membrane was functionalised with triethylenetetramine (TETA). TETA is an organic polyamine ligand known to bind metal ions (such as copper, 41,42 zinc, iron, and nickel), 43 forming metal-organic complexes. Hence, the formation of a metalorganic complex between TETA and Pb(II) metal ions in water was investigated before modifying the surface of the PVC membrane.…”