Polycyanoacrylate porous material for bone tissue substitution

Gel Based on Hydroxyethyl Starch with Immobilized Amikacin for Coating of Bone Matrices in Experimental Osteomyelitis Treatment

A polysaccharide gel containing covalently bound amikacin, a broad-spectrum antibiotic, was produced by using epichlorohydrin-activated hydroxyethyl starch (HES). The structure of the polymers was analyzed by 13C and 1H nuclear magnetic resonance (13C NMR and 1H NMR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The sites of covalent attachment of amikacin to the epoxypropyl substituent and the HES backbone were determined. The antibacterial activity of the polymer was evaluated in vitro using the agar well diffusion method with the Staphylococcus aureus P209 strain. It was demonstrated that the polymer retained activity in the presence of bacterial amylase, which is released upon bacterial attack. The gel was applied for coating pores and surfaces of a biocomposite material based on a xenogenic bovine bone matrix. In vivo experiments showed the effectiveness of utilizing amikacin-containing biocomposite bone-substitute materials in the treatment of experimental osteomyelitis in rats using objective histological control and X-ray tomography.

The fluoride release, abrasion resistance, and cytotoxicity to hGFs of a novel cyanoacrylate-based fluoride varnish compared with conventional fluoride varnish

The important factors contributing to the effectiveness of fluoride varnish are the amount of fluoride ion release and the retention time of the varnish on the tooth surface. Commercial fluoride varnishes are susceptible to mechanical removal; therefore, patients are informed to avoid eating or performing oral hygiene for at least 12-24 h, which results in patient inconvenience. However, cyanoacrylate-based fluoride varnish would not have these disadvantages. This study compared the daily fluoride ion release, abrasion resistance to brushing, and toxicity to human gingival fibroblasts (hGFs) between a newly-developed cyanoacrylate-based fluoride varnish and conventional fluoride varnish (Duraphat varnish). The results demonstrated that the cyanoacrylate varnish had a significantly higher fluoride release for 9 days after application, higher abrasion resistance to brushing, and slightly less toxicity to hGFs compared with Duraphat varnish. This novel cyanoacrylate varnish could be an alternative fluoride varnish for preventing dental caries.

Development of electrospun core-shell polymeric mat using poly (ethyl-2) cyanoacrylate/polyurethane to attenuate biological adhesion on polymeric mesh implants

Poly (ethyl-2) cyanoacrylate was used to create an adhesion-free biocompatible non-woven material reinforced by polyurethane core via a co-axial electrospinning set-up. The effect of relative humidity (RH) of (18, 30, 40, 60, and 68) % on the electrospinning process was examined, and found that in order to achieve well defined core-shell fiber structure, the optimal RH was 18%. If the RH is >18%, a phenomenon called Taylor cone cyclic destabilization occurs, which results in unfavorable surface and mechanical properties of the mat. The developed composite electrospun mat has the potential to be used in medical devices, such as repairing the viscera layer for intraperitoneal hernia mesh implants, which require the attenuation of biological elements, and adequate mechanical properties.

Current status on the biodegradability of acrylic polymers: microorganisms, enzymes and metabolic pathways involved

Abstract

Acrylic polymers (AP) are a diverse group of materials with broad applications, frequent use, and increasing demand. Some of the most used AP are polyacrylamide, polyacrylic acid, polymethyl methacrylates, and polyacrylonitrile. Although no information for the production of all AP types is published, data for the most used AP is around 9 MT/year, which gives an idea of the amount of waste that can be generated after products’ lifecycles. After its lifecycle ends, the fate of an AP product will depend on its chemical structure, the environmental setting where it was used, and the regulations for plastic waste management existing in the different countries. Even though recycling is the best fate for plastic polymer wastes, few AP can be recycled, and most of them end up in landfills. Because of the pollution crisis the planet is immersed, setting regulations and developing technological strategies for plastic waste management are urgent. In this regard, biotechnological approaches, where microbial activity is involved, could be attractive eco-friendly strategies. This mini-review describes the broad AP diversity, their properties and uses, and the factors affecting their biodegradability, underlining the importance of standardizing biodegradation quantification techniques. We also describe the enzymes and metabolic pathways that microorganisms display to attack AP chemical structure and predict some biochemical reactions that could account for quaternary carbon-containing AP biodegradation. Finally, we analyze strategies to increase AP biodegradability and stress the need for more studies on AP biodegradation and developing stricter legislation for AP use and waste control.

Key points

• Acrylic polymers (AP) are a diverse and extensively used group of compounds.

• The environmental fates and health effects of AP waste are not completely known.

• Microorganisms and enzymes involved in AP degradation have been identified.

• More biodegradation studies are needed to develop AP biotechnological treatments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-020-11073-1.

Stainless steel with tailored porosity using canister-free hot isostatic pressing for improved osseointegration implants

Porous biomedical implants hold great potential in preventing stress shielding while improving bone osseointegration and regeneration.