Untapped Potential of Deep Eutectic Solvents for the Synthesis of Bioinspired Inorganic-Organic Materials.

Since the discovery of deep eutectic solvents (DESs) in 2003, significant progress has been made in the field, specifically advancing aspects of their preparation and physicochemical characterization. Their low-cost and unique tailored properties are reasons for their growing importance as a sustainable medium for the resource-efficient processing and synthesis of advanced materials. In this paper, the significance of these designer solvents and their beneficial features, in particular with respect to biomimetic materials chemistry, is discussed.

An overview of the tribological and mechanical properties of PEEK and CFR-PEEK for use in total joint replacements.

Poly-ether-ether-ketone (PEEK) and PEEK composites are outstanding candidates for biomedical applications, such as orthopedic devices, where biocompatibility and modulus match with surrounding tissue are requisite for long-term success. The mechanical properties can be optimized by incorporating fillers such as continuous and chopped carbon fibers. While much is known about the mechanical and tribological behavior of PEEK composites, there are few articles that summarize the viability of using PEEK reinforced with carbon fibers in orthopedic implants.

A methodological framework for nanomechanical characterization of soft biomaterials and polymers.

Nanoindentation utilizes a hard indenter probe to deform the sample surface in order to measure local properties, such as indentation modulus and hardness. Initially intended for characterization of elastic and elastic-plastic materials, nanoindentation has more recently been utilized for viscoelastic solids as well as hydrated and soft biological materials. An advantage to nanoindentation is the ability to determine the nano- and microscale properties of materials with complex microstructures as well as those of limited sample dimension.

Comparison of macro-, micro- and nanomechanical properties of clinically-relevant UHMWPE formulations.

We characterized a set of eleven clinically relevant formulations of UHMWPE for total joint replacements. Although their molecular and supermolecular structure were quite similar as evidenced by IR, DSC and SAXS measurements, there were slight differences in their crystallinity (DSC crystallinity ranging from 52 to 61%), which were connected with processing conditions, such as the total radiation dose, thermal treatment and/or addition of biocompatible stabilizers. Mechanical properties were assessed at all length scales, using macroscale compression testing, non-instrumented and instrumented microindentation hardness testing (at loading forces ~500 mN), and nanoindentation hardness testing measured at both higher and lower loading (~4 mN and ~0.

Nanomechanical analysis of medical grade PEEK and carbon fiber-reinforced PEEK composites.

Polyether ether ketone (PEEK) and PEEK composites are viable candidates for orthopedic implants owing to their ability for modulus match of surrounding bone tissue. The structural properties of these systems for load-bearing application in the body can be tailored by incorporating carbon fibers; to this end, polyacrylonitrile (PAN) and pitch fibers are commonly incorporated in the PEEK matrix. Mechanical property optimization for a given medical application requires consideration of carbon fiber type and volume fraction, as well as processing conditions for the composite systems.

Relationship of Lower Lingual Arch Appliance Use and Impaction of Second Molars: A Retrospective Study.

The purpose of this study was to determine the prevalence of permanent mandibular second molar impaction in pediatric patients treated with a lower lingual holding arch (LLHA) to maintain lower arch perimeter. In this retrospective study, 259 radiographs of nine- to 17-year-old pediatric patients were examined for permanent mandibular second molar impaction. A total of 127 patients with LLHA were compared to a control group of 132 patients who had not received LLHA.

Material properties of ultra-high molecular weight polyethylene: Comparison of tension, compression, nanomechanics and microstructure across clinical formulations.

This is the first study to simultaneously measure material properties in tension, compression, nanoindentation as well as microstructure (crystallinity and lamellar level properties) across a wide variety of clinically relevant ultra-high molecular weight polyethylene (UHMWPE) formulations. Methodologies for the measurement of UHMWPE mechanical properties-namely elastic modulus, yield stress, yield strain, ultimate strength, energetic toughness, Poisson's ratio, hardness and constitutive variables-are evaluated. Engineering stress-strain behavior is compared to true stress-strain behavior for UHMWPE across a range of cross-linking and antioxidant chemistry.