Abstract This study focused on the extraction of cellulose from hemp fiber and production of carbonized nanocelluloses (CCN) from cellulose, characterization, antibiotic loading and investigation of antibacterial properties of cellulose and CCN. Cellulose with a diameter of approximately 4.5 μm was successfully extracted from the untreated hemp fiber that had an average diameter of approximately 10 μm. After the acid hydrolysis, the dried hemp fiber powders were subjected to preoxidation and carbonization and then CCN with a diameter of 34.7 nm was produced. Ciprofloxacin (CIP) was selected as the model antibiotic for investigation of the antibacterial property of the cellulose and CCN. The optimum conditions for CIP loading onto cellulose and CCN were determined to be pH 7.00 for CIP concentrations of 5.0 mg L−1 and the adsorbent dose was 1.0 g L−1 with the loading efficiency of 85.05% and 90.80%, respectively. No chain break was observed with CCN up to 50 mg L−1, but a single chain break was observed for concentrations ≥ 100 mg L−1. The antibacterial activity studies showed that although pristine cellulose and CCN had considerable antibacterial property their modification with CIP (C + CIP and CCN + CIP) increased their activity. At 50 mg mL−1 concentrations, the antibiofilm effectiveness for CCN and cellulose were found to be 52.38% and 4.28%, respectively. The antibiofilm activity of CCN + CIP was also found to be higher than that of cellulose + CIP against both P. aeruginosa and Staphylococcus aureus in the concentrations range studied and the antibiofilm activity was observed to be 94.74% and 86.62% for CCN + CIP and cellulose + CIP, respectively, at 50 mg mL−1. All these results showed that CIP could successfully be loaded onto carbonized nanocelluloses extracted from hemp fibers and they showed considerable antibacterial properties. Graphical abstract

Abstract Hydrogels composed of polyvinyl alcohol (PVA), Pehuen Starch (PS), and TEMPO-oxidized cellulose nanofibrils (TO-CNF) were prepared by the use of a one-pot method that consisted of sonication and freeze-thawing cycles without intermediate separation. Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM), and Micro-Computed Tomography (micro-CT) analyses confirmed that PVA/PS/TO-CNF hydrogels had dynamic behavior (reversible ester bonds and hydrogen bonds), resulting in homogeneous porous architectures. FTIR spectra highlighted chemical structure changes because of the dual cross-linking reaction. Along the same line, rheological measurements indicated a predominantly elastic nature and incremented storage modulus by 20–50%, promoted by the addition of 1 wt.% TO-CNF. Light optical microscopy revealed a fast self-healing behavior within 2 min post-incision, and thermal gravimetry (TGA) confirmed that the inclusion of borax improved thermal stability. Biocompatibility tests with MSCs and HepG2 cells showed non-toxicity, with 1:1 mass ratio PVA/PS-TOCNF hydrogels exhibiting superior dimensional stability, viable cell recovery rates (20–40%), and antimicrobial activity against E. coli. These results demonstrates the potential of biobased polymers (PS-TOCNF) to improve the properties of PVA/borax hydrogels for next-generation healthcare applications, offering a promising solution with competitive mechanical strength, biocompatibility, and antibacterial properties.

Abstract Lightweight and highly porous carboxymethyl cellulose (CMC) aerogels were prepared from CMC solutions via non-solvent induced phase separation, followed by supercritical CO2 drying. Direct freeze-drying of CMC solutions was used to obtain “cryogels” for comparative analysis. The influence of CMC concentration and of drying method on the morphology, density, porosity and mechanical response of CMC aerogels and cryogels under uniaxial compression were evaluated. Two methods were used: direct data collection from the machine sensors and the digital image correlation (DIC) technique. It was demonstrated that DIC method is more precise; video-monitoring of the changes in sample shape and dimensions was also performed. Nominal stress–strain dependences were constructed, and compressive modulus, yield stress, absorbed energy and sample volume evolution under compression were analyzed as a function of density and material morphology. The elastic recovery of cryogels is slightly higher than that of aerogels at the similar density. The “equivalent” Poisson’s ratio (at 50% strain) was nearly zero for cryogels, while for aerogels it was non-zero and decreased with increasing density. The difference in the mechanical response of aerogels vs cryogels was attributed to their different morphology.