scholarly journals Production and Characterization of Cellulose Nanofiber Slurries and Sheets for Biomedical Applications

2021 ◽  
Vol 3 ◽  
Author(s):  
Nicklaus Carter ◽  
Isabelle Grant ◽  
Marley Dewey ◽  
Mary Bourque ◽  
David J. Neivandt

Cellulose nanomaterials are produced employing a multitude of methodologies including electrospinning, bacterial generation, acid digestion, and a variety of mechanical defibrillation techniques; the morphology of the nanomaterial produced is specific to the production process. Feedstocks range from various forms of woody biomass, to fungi, and have a great impact on the resulting product. The mechanical defibrillation technique, such as that employed in the present work, continuously breaks down cellulose fibers suspended in water via segmentation and defibrillation through grinding and refining. The process is typically operated until a desired level of fines is achieved in the resultant slurry of cellulose nanofiber (CNF), alternatively known as cellulose nanofibril. Mechanical defibrillation processes can be built to produce several liters in a small batch system or up to tons per day in a continuous pilot scale refiner system. In the present work a continuous system was developed with the capacity to produce 14 L of cellulose nanofiber slurry with consistent specifications and in a manner compliant with GMP/GLP protocols in order to be amenable to biomedical applications. The system was constructed within an ISO class 7 cleanroom and refining was performed on bleached softwood pulp suspension in purified water. This manuscript details the continuous grinding system, the processes employed to produce cellulose nanofiber, and characterizes the resultant cellulose nanofiber slurry and sheets formed from the slurry.

2020 ◽  
Vol 14 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Xiuqiang Zhang ◽  
Suxia Ren ◽  
Xiaofeng He ◽  
Lili Dong ◽  
Wei Bai ◽  
...  

Zinc oxide (ZnO)/cellulose nanofiber (CNF) nanocomposite films were prepared using cellulose nanofibers and ZnO nanoparticles. First, suspensions of CNF and ZnO mixtures were blended with different CNF/ZnO ratios; then, the mixtures were stirred, homogenized, filtered, and hot pressed to form nanofilms with various ZnO weight ratios (0–50 wt%). Rheological tests showed that the CNF shear thinning behavior was not affected by the addition of ZnO. X-ray diffraction and scanning electron microscopy studies proved the existence of ZnO nanoparticles in the nanocomposite films. Thermogravimetric results indicated that the presence of ZnO had almost no effect on the thermal properties of the composite. As the ZnO content increased, the tensile strength and strain-to-failure rate decreased. In comparison with neat CNF nanofilms, the nanocomposite films showed greater antimicrobial ability against Gram-positive Staphylococcus aureus due to the presence of ZnO nanoparticles, allowing the CNF/ZnO films to be used in some targeted biomedical applications.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 623
Author(s):  
Talles Barcelos da Costa ◽  
Meuris Gurgel Carlos da Silva ◽  
Melissa Gurgel Adeodato Vieira

In a scenario of high demand, low availability, and high economic value, the recovery of rare-earth metals from wastewater is economically and environmentally attractive. Bioadsorption is a promising method as it offers simple design and operation. The aim of this study was to investigate lanthanum bioadsorption using a polymeric bioadsorbent of sericin/alginate/poly(vinyl alcohol)-based biocomposite. Batch system assays were performed to evaluate the equilibrium, thermodynamics, regeneration, and selectivity of bioadsorption. The maximum capture amount of lanthanum at equilibrium was 0.644 mmol/g at 328 K. The experimental equilibrium data were better fitted by Langmuir and Dubinin–Radushkevich isotherms. Ion exchange mechanism between calcium and lanthanum (2:3 ratio) was confirmed by bioadsorption isotherms. Thermodynamic quantities showed that the process of lanthanum bioadsorption was spontaneous (−17.586, −19.244, and −20.902 kJ/mol), endothermic (+15.372 kJ/mol), and governed by entropic changes (+110.543 J/mol·K). The reusability of particles was achieved using 0.1 mol/L HNO3/Ca(NO3)2 solution for up to five regeneration cycles. The bioadsorbent selectivity followed the order of lanthanum > cadmium > zinc > nickel. Additionally, characterization of the biocomposite prior to and post lanthanum bioadsorption showed low porosity (9.95 and 12.35%), low specific surface area (0.054 and 0.019 m2/g), amorphous character, and thermal stability at temperatures up to 473 K. This study shows that sericin/ alginate/poly(vinyl alcohol)-based biocomposites are effective in the removal and recovery of lanthanum from water.


2006 ◽  
Vol 514-516 ◽  
pp. 1005-1009 ◽  
Author(s):  
José V. Araújo ◽  
J.A. Lopes da Silva ◽  
Margarida M. Almeida ◽  
Maria Elisabete V. Costa

Porous chitosan/brushite composite scaffolds were prepared by a freeze-drying technique, starting from brushite suspensions in chitosan solutions. The obtained scaffolds showed a regular macroporous and interconnected structure with brushite particles uniformly distributed in the chitosan matrix. The variation of the brushite concentration affected the microstructure of the final freeze-dried scaffold, in particular, its porosity and its average pore size. The yield strengths of the composite scaffolds could also be improved by the increase of the brushite content.


RSC Advances ◽  
2021 ◽  
Vol 11 (16) ◽  
pp. 9076-9085
Author(s):  
Kanchan Yadav ◽  
Megha Das ◽  
Nurul Hassan ◽  
Archana Mishra ◽  
Jayeeta Lahiri ◽  
...  

A novel nanodot-using protein has been synthesized for the live cell imaging and drug delivery of melatonin in breast cancer cells. Its unique properties hold potential for various biomedical applications in the field of bioimaging and drug delivery.


2011 ◽  
Vol 31 (5) ◽  
pp. 906-914 ◽  
Author(s):  
A. Roguska ◽  
M. Pisarek ◽  
M. Andrzejczuk ◽  
M. Dolata ◽  
M. Lewandowska ◽  
...  

2013 ◽  
Vol 27 (2) ◽  
pp. 216-226 ◽  
Author(s):  
Md. Kamal Khan ◽  
Mohammed Mizanur Rahman ◽  
Bodrun Nesa ◽  
Romana Nasrin ◽  
Swajal Molla ◽  
...  

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