Synthesis, Characterization, and Biological Activity of Amino Acid Derivatives of the Heteropolytungstophosphoric Acid

Rocha

ACS Appl. Mater. Interfaces

et al. 2018

Regulation of wound pH from alkaline to acidic is a simple and powerful approach to reduce wound microbial colonization and infection. Here, we present a nanocomposite material possessing intrinsic acidic surface pH as an innovative antimicrobial wound dressing. This material comprises an agarose matrix nanocomposite containing nanoparticles (NPs) of the cesium salt of phosphotungstic heteropolyacid (Cs2.5H0.5PW12O40). Self-supporting films were prepared by a casting method incorporating 5–20 wt % Cs2.5H0.5PW12O40 NPs into the matrix. Films are flexible with tensile strengths between 28.55 and 32.15 MPa and exhibit broad biocidal activity against neutralophilic pathogens, including Gram-positive bacteria, Gram-negative bacteria, yeast, and filamentous fungi. The nano-antimicrobial Cs2.5H0.5PW12O40 functions as an efficient and self-controlled proton delivery agent that lowers the surface pH of the nanocomposites to the range 7.0 > pH ≥ 3.0. Nanocomposite films containing 20 wt % Cs2.5H0.5PW12O40 NPs presented a surface pH of 3.0 and highest antimicrobial activity. Using quantitative reverse transcription polymerase chain reaction, we demonstrated that the antimicrobial mechanism of the nanocomposites is acid-induced because of the transcriptional induction of glutamate-dependent acid resistance genes in Escherichia coli. Additionally, nanocomposite films do not damage skin according to an in vivo rabbit skin model with no derived edema or erythema. The wound care safety of this material is due to low release of heavy metal heteropolyanions ([PW12O40]3–), no nanoparticle leaching, and proton controlled release resulting in nonirritating acid levels for human skin models.

Section: Discussionmentioning

confidence: 88%

Acidic Dressing Based on Agarose/Cs_2.5H_0.5PW₁₂O₄₀ Nanocomposite for Infection Control in Wound Care

Rocha

ACS Appl. Mater. Interfaces

et al. 2018

“…Hill et al [38] investigated antiviral activity and toxicity of [PW 12 O 40 ] 3− in a cell culture and obtained that IC 50 was 0.1 mM on peripheral blood mononuclear cell. In addition, Kuntic et al [33] was shown that 0.1 mM of WPA and 0.1 mM WPA-A exhibited a low cellular toxicity with viability of Vero cells 94% and 97%, respectively.…”

Section: Discussionmentioning

confidence: 97%

“…reagent grade and were used without further purification. The alanine compound of WPA (WPA-A) was prepared according to a previously developed procedure [33]. The contents of tungsten in the obtained compounds were checked by inductively coupled plasma atomic emission spectroscopy, and the obtained and the theoretical values were in agreement.…”

Section: Chemicalsmentioning

confidence: 99%

Insulin Mimetic Effect of Tungsten Compounds on Isolated Rat Adipocytes

Topić

Milenković

Uskoković‐Marković

et al. 2009

Biol Trace Elem Res

Investigations of effective, orally active, and safe antidiabetic metallopharmaceuticals have been carried out during the last two decades. It has been reported that tungsten compounds mimic the action of insulin in intact cell systems. As insulin mimetics, the most investigated tungsten compound was sodium tungstate (ST), rarely investigated was tungstophosphoric acid (WPA), but never alanine complex of tungstophosphoric acid (WPA-A). In this study, the insulin mimetic activity of three different tungsten compounds, ST, WPA, and WPA-A, was evaluated by means of in vitro measurements of the glucose uptake and inhibition of free fatty acids release from epinephrine-treated isolated rat white adipocytes. We investigated the influence of concentration (lower and higher, 0.1 and 1.0 mM, respectively) and solvent: isotonic salt solution-saline (0.9% w/v of NaCl) and dimethyl sulfoxide (DMSO; 2% v/v), on the biological effect of tested compounds. Our experimental data showed that all of the three investigated tungsten compounds possess insulin mimetic activity in vitro on the isolated adipocytes. Influence of concentration and solvents on insulin mimetic effect for the certain tungsten compounds were: WPA was shown effect independently of concentration and solvents; higher concentration and DMSO were significant decreasing insulin mimetic effect of ST; lower concentration and saline led to decreasing effect of WPA-A. Generally, there were no differences in insulin mimetic effect of three tungsten compounds in lower concentration and dissolved in DMSO. When saline was used as solvent, it was needed higher concentration of investigated compounds to accomplish the same effect. In conclusion, our results suggest that low concentration (0.1 mM) of ST, WPA, and WPA-A dissolved in 2% DMSO could be the good candidates for in vivo investigation of their antidiabetic properties.

“…These studies open the door to new approaches for drug encapsulation and controlled release using POMs as building blocks for the construction of novel 3D hierarchical structures. Despite a previous study showing the lack of cytotoxic effects of phosphotungstic acid on Vero cells, the in vitro or in vivo cytotoxicity and antitumour activity of the developed composites were not evaluated. Therefore, further studies evaluating the biological performance of the described composite would be needed.…”

Section: Polyoxometalates As Building Blocks For the Design Of Novmentioning

confidence: 98%

Polyoxometalate Composites in Cancer Therapy and Diagnostics

et al. 2020

Polyoxometalates (POMs) are metal‐oxide inorganic clusters, mostly anionic, where the metal is usually a transition metal (such as V, W, or Mo). Owing to their great variety of structures and large range of molecular dimensions, POMs have attracted considerable attention over the years. The high solubility in water together with the extent of their redox chemistry make POMs and their composites very versatile materials that find many applications in the biomedical field such as drug delivery systems or anti‐viral and anti‐tumoural agents. While the antitumoural activity of POMs and their derivatives is well documented, their application in emergent cancer therapies has not been addressed. This review presents the application of POM‐based composites as photothermal agents, radiosensitisers, and biosensors. The latest advances in the design of novel POM nanocomposites for cancer theranostics are also highlighted.