Alginate-based composite materials for wound dressing application:A mini review

Removal of strontium from aqueous solutions by adsorption onto activated carbon: kinetic and thermodynamic studies

Recent advances in embedded three-dimensional (3D) bioprinting have expanded the design space for fabricating geometrically complex tissue scaffolds using hydrogels with mechanical properties comparable to native tissues and organs in the human body. The advantage of approaches such as Freeform Reversible Embedding of Suspended Hydrogels (FRESH) printing is the ability to embed soft biomaterials in a thermoreversible support bath at sizes ranging from a few millimeters to centimeters. In this study, we were able to expand this printable size range by FRESH bioprinting a full-size model of an adult human heart from patient-derived magnetic resonance imaging (MRI) data sets. We used alginate as the printing biomaterial to mimic the elastic modulus of cardiac tissue. In addition to achieving high print fidelity on a low-cost printer platform, FRESH-printed alginate proved to create mechanically tunable and suturable models. This demonstrates that large-scale 3D bioprinting of soft hydrogels is possible using FRESH and that cardiac tissue constructs can be produced with potential future applications in surgical training and planning.

FRESH 3D Bioprinting a Full-Size Model of the Human Heart.

The dissolution and leaching of minerals: Mechanisms, myths and misunderstandings

Biopolymers are materials synthesised or derived from natural sources, such as plants, animals, microorganisms or any other living organism. The use of these polymers has grown significantly in recent years as industry shifts away from unsustainable fossil fuel resources and looks towards a softer and more sustainable environmental approach. This review article covers the main classes of biopolymers: Polysaccharides, proteins, microbial-derived and lignin. In addition, an overview of the leading biomedical applications of biopolymers is also provided, which includes tissue engineering, medical implants, wound dressings, and the delivery of bioactive molecules. The future clinical applications of biopolymers are vast, due to their inherent biocompatibility, biodegradability and low immunogenicity. All properties which their synthetic counterparts do not share.

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Cellulose Nanofibers and Other Biopolymers for Biomedical Applications. A Review

The leaching kinetics of a zinc sulphide concentrate in acid ferric sulphate

Hydrogels have been studied as promising materials in different biomedical applications such as cell culture in tissue engineering or in wound healing. In this work, we synthesized different nanocellulose-alginate hydrogels containing cellulose nanocrystals, TEMPO-oxidized cellulose nanocrystals (CNCTs), cellulose nanofibers or TEMPO-oxidized cellulose nanofibers (CNFTs). The hydrogels were freeze-dried and named as gels. The nanocelluloses and the gels were characterized by different techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA), while the biological features were characterized by cytotoxicity and cell growth assays. The addition of CNCTs or CNFTs in alginate gels contributed to the formation of porous structure (diameter of pores in the range between 40 and 150 μm). TEMPO-oxidized cellulose nanofibers have proven to play a crucial role in improving the dimensional stability of the samples when compared to the pure alginate gels, mainly after a thermal post-treatment of these gels containing 50 wt % of CNFT, which significantly increased the Ca2+ crosslinking density in the gel structure. The morphological characteristics, the mechanical properties, and the non-cytotoxic behavior of the CNFT-alginate gels improved bioadhesion, growth, and proliferation of the cells onto the gels. Thus, the alginate-nanocellulose gels might find applications in tissue engineering field, as for instance, in tissue repair or wound healing applications.

Three-Dimensional Stable Alginate-Nanocellulose Gels for Biomedical Applications: Towards Tunable Mechanical Properties and Cell Growing.

A study concerning the resin PUROLITE S-930 as a substrate to remove nickel and cobalt from sulphuric solution is herein presented. The influence of nickel and cobalt concentrations was studied, and the results have shown a greater selection of the resins for solutions rich in nickel (Ni 600 mg/L - Co 800 mg/L). The adsorption isotherms showed an increase in the resin adsorption capacity at higher temperatures (qmax Ni 0.28 mol/L, at 70oC and qmax Co 0.18 mol/L, at 60oC). The enthalpy values suggested endothermic physisorption. The Homogeneous Surface Diffusion Model (HSDM) was chosen for modeling the adsorption kinetics of metals in a fixed-bed column. The results showed good agreement with the model. Both, kf = 5.2x10-6 m/s and DS = 4.5x10-12 m2/s indicated that resin loading is based on transport through the boundary layer and porous diffusion in the resin.

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Priscila de Freitas Siqueira

Papers

The leaching kinetics of a zinc sulphide concentrate in acid ferric sulphate

Three-Dimensional Stable Alginate-Nanocellulose Gels for Biomedical Applications: Towards Tunable Mechanical Properties and Cell Growing.

Adsorção de níquel e cobalto em resina de troca iônica como alternativa para o tratamento de licor de lixiviação