The physiological polyphosphate as a healing biomaterial for chronic wounds:Crucial roles of its antibacterial and unique metabolic energy supplying properties

Insufficient metabolic energy,in the form of adenosine triphosphate(ATP),and bacterial infections are among the main causes for the development of chronic wounds.Previously we showed that the physi-ological inorganic polymer polyphosphate(polyP)massively accelerates wound healing both in animals(diabetic mice)and,when incorporated into mats,in patients with chronic wounds.Here,we focused on a hydrogel-based gel formulation,supplemented with both soluble sodium polyP(Na-polyP)and amor-phous calcium polyP nanoparticles(Ca-polyP-NP).Exposure of human epidermal keratinocytes to the gel caused a significant increase in extracellular ATP level,an effect that was even enhanced when Na-polyP was combined with Ca-polyP-NP.Furthermore,it is shown that the added polyP in the gel is converted into a coacervate,leading to encapsulation and killing of bacteria.The data on human chronic wounds showed that the administration of hydrogel leads to the complete closure of these wounds.Histological analysis of biopsies showed an increased granulation of the wounds and an enhanced microvessel forma-tion.The results indicate that the polyP hydrogel,due to its properties to entrap bacteria and generate metabolic energy,is a very promising formulation for a new therapy for chronic wounds.

Effect of functional groups on the crystallization of ferric oxides/oxyhydroxides in suspension environment

This paper investigated the effects of five kinds of Au surfaces terminated with and without functional groups on the crystallization of ferric oxides/oxyhydroxides in the suspension condition. Self-assembled monolayers （SAMs） were used to create hydroxyl （-OH）, carboxyl （-COOH）, amine （-NH2） and methyl （-CH3） functionalized surfaces, which proved to be of the same surface density. The immersion time of substrates in the Fe（OH）3 suspension was divided into two time portions. During the first period of 2 h, few ferric oxide/oxyhydroxide was deposited except that E-Fe203 was detected on -NH2 surface. Crystallization for 10h evidenced more kinds of iron compounds on the functional surfaces. Goethite and maghemite were noticed on four functional surfaces, and maghemite also grew on Au surface. Deposition of ^-Fe203 was found on -OH surface, while the growth of orthorhombic and hexagon FeOOH were indicated on -NH2 surface. Considering the wide existence of iron compounds in nature, our investigation is a precedent work to the study of iron biomineralization in the suspension area.