Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration.

Evidence that otoliths, mineral-rich limestone concrescences present in the inner ear of bone fishes, can accelerate bone formation in vivo has been previously reported. The goal of this work was the development, characterization, and evaluation of the cytocompatibility of otoliths-incorporated sodium alginate and gelatin scaffolds. Cynoscion acoupa-derived otoliths were characterized by X-ray fluorescence spectrometry (FRX), particle size, free lime, and weight loss by calcination. Furthermore, otoliths were incorporated into sodium alginate (ALG/OTL-s) or gelatin (GEL/OTL-s) scaffolds, previously developed by freeze-drying. Then, the scaffolds were characterized by thermogravimetric analysis (TGA/DTG), differential scanning calorimetry (DSC), infrared spectroscopy with Fourier transform (FTIR), swelling tests, and scanning electron microscopy (SEM). Cytotoxicity assays were run against J774.G8 macrophages and MC3T3-E1 osteoblasts. Data obtained from TGA/DTG, DSC, and FTIR analyses confirmed the interaction between otoliths and the polymeric scaffolds. SEM showed the homogeneous porous 3D structure rich in otolith micro-fragments in both scaffolds. Swelling of the GEL/OTL-s (63.54 ± 3.0%) was greater than of ALG/OTL-s (13.36 ± 9.9%) (p < 0.001). The viability of J774.G8 macrophages treated with both scaffolds was statistically similar to the group treated with DMEM only (p > 0.05) and significantly higher than that treated with Triton-X (p < 0.01) at 72 h. Both scaffolds showed approximately 100% growth of MC3T3-E1 osteoblasts by 24 h, similarly to control (p > 0.05). However, by 48 h, only ALG/OTL-s showed growth similar to control (p > 0.05), whereas GEL/OTL showed a significantly lower growth index (p < 0.05). In conclusion, the physicochemical profiles suggest proper interaction between the otoliths and the two developed polymeric 3D scaffolds. Moreover, both materials showed cytocompatibility with J774.G8 macrophages but the growth of MC3T3-E1 osteoblasts was higher when exposed to ALG/OTL-s. These data suggest that sodium alginate/otoliths scaffolds are potential biomaterials to be used in bone regeneration applications. Graphical abstract.

Polyesters from Macrolactones Using Commercial Lipase NS 88011 and Novozym 435 as Biocatalysts.

The demand for environmentally friendly products allied with the depletion of natural resources has increased the search for sustainable materials in chemical and pharmaceutical industries. Polyesters are among the most widely used biodegradable polymers in biomedical applications. In this work, aliphatic polyesters (from globalide and ω-pentadecalactone) were synthesized using a new commercial biocatalyst, the low-cost immobilized NS 88011 lipase (lipase B from Candida antarctica immobilized on a hydrophobic support). Results were compared with those obtained under the same conditions using a traditional, but more expensive, commercial biocatalyst, Novozym 435 (lipase B from C. antarctica immobilized on Lewatit VP OC). When NS 88011 was used in the polymerization of globalide, longer reaction times (240 min)-when compared to Novozym 435-were required to obtain high yields (80-90 wt%). However, higher molecular weights were achieved. When poly(ω-pentadecalactone) was synthesized, high yields and molecular weights (130,000 g mol-1) were obtained and the enzyme concentration showed strong influence on the polyester properties. This is the first report describing NS 88011 in polymer synthesis. The use of this cheaper enzymatic preparation can provide an alternative for polyester synthesis via enzymatic ring-opening polymerization.

Esterification activity of novel fungal and yeast lipases.

The main objective of this work was the isolation and screening of microorganisms with potential for producing lipases for the synthesis of fatty esters as well as evaluating the specificity of the enzymes produced, using different alcohols (methanol, ethanol, n-propanol, and butanol) and fatty acids (oleic and lauric acids) as substrates. Promising biocatalysts for organic synthesis were obtained in this work. The isolated strains 69F and 161Y showed ability to efficiently catalyze the reaction for production of n-propyl oleate. Other strains can also be considered of potential interest, as 74F, 111Y, and 186Y. The future development of production using different substrates could result in cheap crude lipase of high importance to industrial applicability.