scholarly journals An environmentally benign approach to achieving vectorial alignment and high microporosity in bacterial cellulose/chitosan scaffolds

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 13678-13688 ◽  
Author(s):  
Guohui Li ◽  
Avinav G. Nandgaonkar ◽  
Youssef Habibi ◽  
Wendy E. Krause ◽  
Qufu Wei ◽  
...  

Bacterial cellulose (BC) nanofibers secreted by Komagataeibacter xylinus 10245 were applied alone or with chitosan to prepare highly aligned and porous scaffolds through a liquid nitrogen-initiated ice “templating” and freeze-drying process.

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16737-16737 ◽  
Author(s):  
Guohui Li ◽  
Avinav G. Nandgaonkar ◽  
Youssef Habibi ◽  
Wendy E. Krause ◽  
Qufu Wei ◽  
...  

Correction for ‘An environmentally benign approach to achieving vectorial alignment and high microporosity in bacterial cellulose/chitosan scaffolds’ by Guohui Li et al., RSC Adv., 2017, 7, 13678–13688.


2020 ◽  
Vol 11 (1) ◽  
pp. 7357-7367

The elaboration of scaffolds for use in tissue regeneration processes plays an important role in the area of biomaterials. Natural and synthetic polymers, together with calcium phosphates, form suitable compounds for these studies because their combinations favor the union of the properties of both materials, such as their biocompatibility, biofunctionality, shape, porosity, and mechanical properties. The objective of this work was to develop a scaffold of amorphous calcium phosphate and bacterial cellulose, applying a freeze-drying process. The results demonstrated the feasibility of scaffolds elaboration applying the freeze-drying methodology. The formulation that presented the best results was the one that contained amorphous calcium phosphate (50%), bacterial cellulose gel (20%), and sodium alginate (30%). Cytotoxicity studies showed that the studied formulation did not present cytotoxicity, promoting cell viability.


Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 772
Author(s):  
Estefanía Álvarez-Castillo ◽  
Carlos Bengoechea ◽  
Antonio Guerrero

The replacement of common acrylic derivatives by biodegradable materials in the formulation of superabsorbent materials would lessen the associated environmental impact. Moreover, the use of by-products or biowastes from the food industry that are usually discarded would promote a desired circular economy. The present study deals with the development of superabsorbent materials based on a by-product from the meat industry, namely plasma protein, focusing on the effects of a freeze-drying stage before blending with glycerol and eventual injection molding. More specifically, this freeze-drying stage is carried out either directly on the protein flour or after its solubilization in deionized water (10% w/w). Superabsorbent materials obtained after this solubilization-freeze-drying process display higher Young’s modulus and tensile strength values, without affecting their water uptake capacity. As greater water uptake is commonly related to poorer mechanical properties, the proposed solubilization-freeze-drying process is a useful strategy for producing strengthened hydrophilic materials.


Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 839
Author(s):  
Karina Jasińska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska

The study aimed to evaluate the impact of selected factors of the freeze-drying process on the hydrolytic and synthetic activity of the extracellular lipases of Y. lipolytica KKP 379 and to attempt the use of the crude enzyme preparation as a biocatalyst in the synthesis of geranyl 4-hydroxyphenylpropanoate. Antioxidant and antibacterial properties of the geranyl ester derivative were also investigated in order to evaluate their usefulness as a novel food additive. The studies confirmed that freeze-drying was an effective method of dehydrating yeast supernatant and allowed for obtaining lyophilizates with low water activity from 0.055 to 0.160. The type and concentration of the additive (2–6% whey protein hydrolyzate, 0.5% and 1% ammonium sulphate) had a significant effect on the hydrolytic activity of enzyme preparations, while the selected variants of drying temperature during the freeze-drying process were not significant (10 °C and 50 °C). Low yield of geranyl 4-hydroxyphenylopropionate was shown when the lyophilized supernatant was used (5.3%), but the yield of ester synthesis increased when the freeze-dried Y. lipolytica yeast biomass was applied (47.9%). The study confirmed the antioxidant properties of the synthesized ester by the DPPH• and CUPRAC methods, as well as higher antibacterial activity against tested bacteria than its precursor with 0.125 mM MIC (minimal inhibitory concentration) against L. monocytogenes.


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