Important parameters in plasma jets for the production of RONS in liquids for plasma medicine: A brief review

Reactive oxygen and nitrogen species (RONS) are among the key factors in plasma medicine. They are generated by atmospheric plasmas in biological fluids, living tissues and in a variety of liquids. This ability of plasmas to create a delicate mix of RONS in liquids has been used to design remote or indirect treatments for oncological therapy by treating biological fluids by plasmas and putting them in contact with the tumour;Documented effects include selective cancer cell toxicity, even though the exact mechanisms involved are still under investigation. However, the "right" dose for suitable therapeutical activity is crucial and still under debate. The wide variety of plasma sources hampers comparisons. This review focuses on atmospheric pressure plasma jets as the most studied plasma devices in plasma medicine and compiles the conditions employed to generate RONS in relevant liquids and the concentration ranges obtained. The concentrations of H2O2, NO2^-, NO3^- and short-lived oxygen species are compared critically to provide a useful overview for the reader.

Novel synthesis method combining a foaming agent with freeze-drying to obtain hybrid highly macroporous bone scaffolds

Three-dimensional macroporous scaffolds are commonly used in bone tissue engineering applications since they provide sufficient space for cell migration and proliferation, facilitating bone ingrowth and implant vascularisation. The aim of this work was to combine two simple methods, freeze-drying and gas-foaming, in order to fabricate highly macroporous bone scaffolds made of chitosan/agarose matrix reinforced with nanohydroxyapatite. The secondary goal of this research was to comprehensively assess biomedical potential of developed biomaterials. In this work, it was demonstrated that simultaneous application of freeze-drying and gas-foaming technique allows to obtain hybrid(as proven by ATR-FTIR)macroporous bone scaffolds(pore diameter > 50 um) characterized by high open(70%) and interconnected porosity. Novel scaffolds were non-toxic, favoured osteoblasts adhesion and growth and induced apatite formation on their surfaces, indicating their high bioactivity that is essential for good implant osseointegration. Biomaterials were also prone to enzymatic degradation, degradation in acidified microenvironment(e.g. osteoclast-mediated), and slow degradation under physiological p H of 7.4.Moreover, the scaffolds revealed microstructure(70% open porosity, SSA approx. 30 m2/g, high share of macropores with diameter in the range 100-410 um) and compressive strength(1–1.4 MPa) comparable to cancellous bone, indicating that they are promising implants for cancellous bone regeneration.

Powder metallurgy with space holder for porous titanium implants:A review

One of the biggest challenges in the biocompatibility of implantable metals is the prevention of the stress shielding effect,which is related to the coupling of the bone-metal mechanical properties.This stress shielding phenomenon provokes bone resorption and the consequent adverse effects on prosthesis fixation.However,it can be inhibited by adapting the stiffness of the implant material.Since the use of titanium(Ti)porous structures is a great alternative not only to inhibit this effect but also to improve the osteointegration of orthopedic and dental implants,a brief description of the techniques used for their manufacturing and a review of the current commercialized implants produced from porous Ti assemblies are compiled in this work.As powder metallurgy(PM)with space holder(SH)is a powerful technology used to produce porous Ti structures,it is here discussed its potential for the fabrication of medical devices from the perspectives of both design and manufacture.The most important parameters of the technique such as the size and shape of the initial metallic particles,the SH and binder type of materials,the compaction pressure of the green form,and in the sintering stage,the temperature,atmosphere,and time are reviewed according to the bibliography reported.Furthermore,the importance of the porosity and its types together with the influence of the mentioned parameters in the final porosity and,consequently,in the ultimate mechanical properties of the structure are discussed.Finally,a few examples of the PM-SH application for the manufacturing of orthopedic implants are presented.