A Cost-Effective and Chemical-Recycling Approach for Facile Preparation of Regenerated Cellulose Materials.

Cellulose is difficult to melt or dissolve. The dissolution and regeneration process paves the way to convert cellulose into diverse forms but still suffers from high costs and environmental pollution. Here, we developed a method that uses aqueous alkali to efficiently dissolve cellulose at a temperature above 0 °C in minutes for fabricating regenerated cellulose. Cellulose was modified with minimal carboxymethyl groups to weaken the intermolecular interaction and improve its dissolution. The modified cellulose can be commercially obtained from carboxymethyl cellulose manufacturing with low cost and high quality. The use of only aqueous alkali reduces pollution and facilitates chemical recycling, and the moderate dissolving temperature reduces energy consumption. The regenerated cellulose materials display excellent mechanical properties and can be recycled or biodegraded after use. The method allows the use of diverse raw materials and modifications to broaden its applicability. The study develops a low-cost and eco-friendly method to fabricate regenerated cellulose.

Strong, Lightweight, and Shape-Memory Bamboo-Derived All-Cellulose Aerogels for Versatile Scaffolds of Sustainable Multifunctional Materials.

Strong, lightweight, and shape-memory cellulose aerogels have great potential in multifunctional applications. However, achieving the integration of these features into a cellulose aerogel without harsh chemical modifications and the addition of mechanical enhancers remains challenging. In this study, a strong, lightweight, and water-stimulated shape-memory all-cellulose aerogel (ACA) is created using a combination strategy of partial dissolution and unidirectional freezing from bamboo. Benefiting from the firm architecture of cellulose microfibers bridging cellulose nanofibers /regenerated cellulose aggregated layers and the bonding of different cellulose crystal components (cellulose Iß and cellulose II), the ACA, with low density (60.74 mg cm-3 ), possesses high compressive modulus (radial section: 1.2 MPa, axial section: 0.96 MPa). Additionally, when stimulated with water, the ACA exhibits excellent shape-memory features, including highly reversible compression-resilience and instantaneous fold-expansion behaviors. As a versatile scaffold, ACA can be integrated with hydroxyapatite, carboxyl carbon nanotubes, and LiCl, respectively, via a simple impregnation method to yield functionalized cellulose composites for applications in thermal insulation, electromagnetic interference shielding, and piezoresistive sensors. This study provides inspiration and a reliable strategy for the elaborately structural design of functional cellulose aerogels endows application prospects in various multifunction opportunities.

Interfacial Membranization of Regenerated Cellulose Nanoparticles and a Protein Renders Stable Water-in-Water Emulsion.

Pickering water-in-water (W/W) emulsions stabilized by biobased colloids are pertinent to engineering biomaterials with hierarchical and confined architectures. In this study, stable W/W emulsions are developed through membranization utilizing biopolymer structures formed by the adsorption of cellulose II nanospheres and a globular protein, bovine serum albumin (BSA), at droplet surfaces. The produced cellulose II nanospheres (NPcat, 63 nm diameter) bearing a soft and highly accessible shell, endow rapid and significant binding (16 mg cm- 2) with BSA. NPcat and BSA formed complexes that spontaneously stabilized liquid droplets, resulting in stable W/W emulsions. It is proposed that such a system is a versatile all-aqueous platform for encapsulation, (bio)catalysis, delivery, and synthetic cell mimetics.

Facile Fabrication of Zeolitic Imidazolate Framework-8@Regenerated Cellulose Nanofibrous Membranes for Effective Adsorption of Tetracycline Hydrochloride.

The excessive utilization of antimicrobials in humans and animals has resulted in considerable environmental contamination, necessitating the development of high-performance antibiotic adsorption media. A significant challenge is the development of composite nanofibrous materials that are both beneficial and easy to fabricate, with the aim of improving adsorption capacity. Herein, a new kind of zeolitic imidazolate framework-8 (ZIF-8)-modified regenerated cellulose nanofibrous membrane (ZIF-8@RC NFM) was designed and fabricated by combining electrospinning and in situ surface modification technologies. Benefiting from its favorable surface wettability, enhanced tensile strength, interconnected porous structure, and relatively large specific surface area, the resulting ZIF-8@RC NFMs exhibit a relatively high adsorption capacity for tetracycline hydrochloride (TCH) of 105 mg g-1 within 3 h. Moreover, a Langmuir isotherm model and a pseudo-second-order model have been demonstrated to be more appropriate for the description of the TCH adsorption process of ZIF-8@RC-3 NFMs. Additionally, this composite fibrous material could keep a relatively stable adsorption capability under various ionic strengths. The successful fabrication of the novel ZIF-8@RC NFMs may shed light on the further development of wastewater adsorption treatment materials.

Heat-Resistant, Robust, and Hydrophilic Separators Based on Regenerated Cellulose for Advanced Supercapacitors.

Separators in supercapacitors (SCs) typically suffer from defects of low mechanical property, limited ion transport, and electrolyte wettability, and poor thermal stability, impeding the development of SCs. Herein, high-performance regenerated cellulose (RC) based separators are designed that are fabricated by effective hydrolytic etching of inorganic CaCO3 nanoparticles from a filled RC membrane. The as-prepared RC separator displays excellent comprehensive performances such as higher tensile strength (75.83 MPa) and thermal stability (200 °C), which is superior to commercial polypropylene-based separator (Celgard 2500) and sufficient to maintain their structural integrity even at temperatures in excess of 200 °C. Benefiting from its hydrophilicity, high porosity, and outstanding electrolyte uptake rate (208.5%), the RC separator exhibits rapid transport and permeability of ions, which is 2.5× higher than that of the commercial nonwoven polypropylene separator (NKK -MPF30AC-100) validated by electrochemical tests in the 1.0 m Na2 SO4 electrolyte. Results show that porous RC separator with unique advantages of superior electrolyte wettability, mechanical robustness, and high thermal stability, is a promising separator for SCs with high-performance and safety.

Hemostatic effect and safety evaluation of oxidized regenerated cellulose in total knee arthroplasty- a randomized controlledtrial.

BACKGROUND: Oxidized regenerated cellulose (ORC) is a type of biodegradable hemostatic material, which has been widely used in the field of surgery. However, its hemostatic effect in patients undergoing total knee arthroplasty (TKA) is uncertain. Accordingly, this study investigated the effectiveness and safety of ORC in patients receiving TKA. METHODS: Seventy patients undergoing unilateral TKA were randomized into blank control group and ORC (2 pieces of ORC placed in the joint cavity) groups. Then, the two groups were compared for primary (perioperative blood loss [total blood loss, intraoperative blood loss, and hidden blood loss] and hemoglobin drop values) and secondary (coagulation indicators, inflammatory indicators,operation time, and complication rates) outcomes. RESULTS: The total blood loss in the ORC group was 902.32 ± 307.82 mL, which was statistically significantly lower than that in the control group (1052.25 ± 308.44 mL) (P < 0.05). Postoperative hidden blood loss was also statistically markedly lower in the ORC group (801.61 ± 298.80 mL) than in the control group (949.96 ± 297.59 mL) (P < 0.05). There was no significant difference between the two groups in terms of coagulation indicators, inflammatory indicators, operation time, and complication rates. CONCLUSION: In conclusion, our prospective RCT study proved that regenerated oxidized cellulose can be used safely in vivo and can effectively reduce postoperative blood loss in patients, which is a potential method for preventing blood loss after TKA. TRIAL REGISTRATION: This prospective RCT was reviewed and approved by the Ethics Committee of Honghui Hospital of Xi'an Jiaotong University (No: 202,211,007) and was designed and conducted according to the rules of the Declaration of Helsinki. Written informed consent was obtained from patients or their legal guardians.

Physical and chemical effects of conventional microplastic glitter versus alternative glitter particles on a freshwater plant (Lemnaceae: Lemna minor).

Glitters are primary microplastics which are directly littered into the environment, yet the ecological effects have seldom been tested. When microplastics enter the environment, their physical presence and chemical leachate may alter the physiology of primary producers. Glitter can be composed of plastic or natural and/or biodegradable materials, often with additives. Three experiments were run for 14 days to separate chemical and physical effects of different types of glitter: polyethylene terephthalate (PET), biodegradable modified regenerated cellulose (MRC), synthetic mica, and a natural particle control (kaolinite) on several physical characteristics of Lemna minor (common duckweed). L. minor was exposed to either fresh (chemical and physical effects), leachate from glitter (chemical) or aged glitter (physical). Overall, there was little effect of PET, synthetic mica, kaolinite or of any aged glitter. High concentrations of fresh MRC glitters, however, decreased root length, biomass and chlorophyll content of L. minor. Some of these effects were also present when exposed to leachate from MRC glitters, but were less pronounced. Elemental analysis revealed the presence of metals in MRC glitters which may explain these responses. Short-term ecotoxicity of biodegradable glitters can arise due to their physical and chemical properties, but may lessen over time as their surface coating degrades.

Rod-like Cellulose Regenerated by Bottom-Up Assembly in Natural Rubber Latex and Its Reinforcement.

As a renewable biomass material, nano-cellulose has been investigated as a reinforcing filler in rubber composites but has seen little success because of its strong inclination towards aggregating. Here, a bottom-up self-assembly approach was proposed by regenerating cellulose crystals from a mixture of cellulose solution and natural rubber (NR) latex. Different co-coagulants of both cellulose solution and natural rubber latex were added to break the dissolution equilibrium and in-situ regenerate cellulose in the NR matrix. The SEM images showed that the sizes and morphologies of regenerated cellulose (RC) varied greatly with the addition of different co-coagulants. Only when a 5 wt% acetic acid aqueous solution was used, the RC particles showed an ideal rod-like structure with small sizes of about 100 nm in diameter and 1.0 µm in length. The tensile test showed that rod-like RC (RRC)-endowed NR vulcanizates with pronounced reinforcement had a drastic upturn in stress after stretching to 200% strain. The results of XRD and the Mullins effect showed that this drastic upturn in stress was mainly attributed to the formation of rigid RRC-RRC networks during stretching instead of the strain-induced crystallization of NR. This bottom-up approach provided a simple way to ensure the effective utilization of cellulosic materials in the rubber industry.

A meta-analysis examined the effect of oxidised regenerated cellulose/collagen dressing on the management of chronic skin wounds.

To assess the impact of oxidised regenerated cellulose/collagen dressing on the management of chronic skin wounds, we conducted a meta-analysis. A thorough review of the literature up to September 2022 revealed that 1521 participants had chronic skin wounds at the start of the investigations; 763 of them used oxidised regenerated cellulose/collagen dressing, while 758 received control. Using dichotomous or contentious methods and a random or fixed-effect model, odds ratios (OR) and mean difference (MD) with 95% confidence intervals (CIs) were estimated to evaluate the impact of oxidised regenerated cellulose/collagen dressing on the management of chronic skin wounds. The oxidised regenerated cellulose/collagen dressing had significantly higher complete wound healing (OR, 1.74; 95% CI, 1.06-2.85; P = .03), higher wound relative reduction percent (MD, 13.50; 95% CI, 2.39-24.61; P = .02), and lower adverse events in wound healing (OR, 0.63; 95% CI, 0.41-0.98; P = .04) compared with control in chronic skin wounds. The oxidised regenerated cellulose/collagen dressing had significantly higher complete wound healing, higher wound relative reduction percent and lower adverse events in wound healing compared with control in chronic skin wounds. The low sample size of 8 out of 10 researches in the meta-analysis and the small number of studies in several comparisons calls for care when analysing the results.

Environmentally dependent adsorption of 2,4-dichlorophenol on cellulose-chitosan self-assembled composites.

With the increasing need for bio-based materials developed by environmentally friendly procedures, this work shows a green method to develop shape-controlled structures from cellulose dissolving pulp coated by chitosan. This material was then tested to adsorb a common and widespread pollutant, 2,4-dichlorophenol under different pH conditions (5.5 and 9). Herein it was noticed that the adsorption only occurred in acidic pH (5.5) where electrostatic interaction drove the adsorption, demonstrating the potential to tune the response under desired conditions only. The adsorption was successful in the hydrogel structure with an adsorption capacity of 905 ± 71 mg/g from a solution with 16.6 ppm; furthermore, adsorption was also possible with dried hydrogel structures, presenting a maximum of adsorption of 646 ± 50 mg/g in a similar 16.6 ppm solution. Finally, adsorbent regeneration was successfully tested for both, dry (rewetted) and never-dried states, showing improved adsorption after regeneration in the case of the never dried hydrogel structures.

Clinical observation of the regeneration process of defects after breast cancer resection.

BACKGROUND: The present study aims to use two different kinds of filling materials, oxidized regenerated cellulose and gelatin sponge, to repair defects of breast-conserving surgery due to breast cancer, and compare the clinical efficacy, cosmetic effect and complication rate among groups. METHODS: A total of 125 patients, who had breast -conserving surgery due to breast cancer, were enrolled into the present study. Postoperative efficacy was assessed by a doctor and patient, according to the Harvard/NSABP/RTOG Breast Cosmetic Grading Scale. RESULTS: Among these patients, 41 patients received conventional breast-conserving surgery, and 84 patients received breast-conserving surgery plus filling implantation (41 patients in the oxidized regenerated cellulose group and 43 patients in the gelatin sponge group). All patients had small to medium sized breasts (cup size A and B). The average weight of tumor tissues was 56.61 ± 11.57 g in the conventional breast-conserving surgery group, 58.41 ± 8.53 g in the oxidized regenerated cellulose group, and 58.77 ± 9.90 g in the gelatin sponge group. The difference in pathological factors, average operation time, length of stay and local infection rate was not statistically significant among the three groups. 18 patients in the oxidized regenerated cellulose group and 15 patients in the gelatin sponge group were evaluated to have a good cosmetic effect by the surgeon and patient, while 12 patients in the conventional breast-conserving surgery group were evaluated to be have good cosmetic effect by the surgeon and patient. The cosmetic effects in the oxidized regenerated cellulose group and gelatin sponge group were comparable, and these were superior to those in the conventional breast-conserving surgery group. CONCLUSION: The use of oxidized regenerated cellulose and gelatin sponge is a feasible approach for defect repair after breast-conserving surgery.

Breast conserving surgery using oxidized regenerated cellulose as filling biomaterial: recommendations to improve clinical outcomes.

Oxidized regenerated cellulose is considered an optimal local hemostatic agent thanks to its favorable biocompatibility, absorption characteristics and ease-of-use. Recently, oxidized regenerated cellulose has also been used as a filler in breast conserving surgery with a reconstructive purpose in order to repair partial breast defects and improve aesthetic outcomes. However, some postoperative problems due to its use, such as allergic reactions, seroma, foreign-body reaction and misdiagnosis during the follow-up of breast cancer patients, have been shown. These possible surgical complications can undermine clinical outcomes and lead to delay the beginning of oncological treatments with a negative impact on patient quality of life and survival. An adequate surgical expertise and the compliance with some specific recommendations are crucial in order to minimize postoperative issues and optimise aesthetic outcomes.

Variants of Oxidized Regenerated Cellulose and Their Distinct Effects on Neuronal Tissue.

Based on oxidized regenerated cellulose (ORC), several hemostyptic materials, such as Tabotamp®, Equicel® and Equitamp®, have been developed to approach challenging hemostasis in neurosurgery. The present study compares ORC that differ in terms of compositions and properties, regarding their structure, solubility, pH values and effects on neuronal tissue. Cytotoxicity was detected via DNA-binding fluorescence dye in Schwann cells, astrocytes, and neuronal cells. Additionally, organotypic hippocampal slice cultures (OHSC) were analyzed, using propidium iodide, hematoxylin-eosin, and isolectin B4 staining to investigate the cellular damage, cytoarchitecture, and microglia activation. Whereas Equicel® led to a neutral pH, Tabotamp® (pH 2.8) and Equitamp® (pH 4.8) caused a significant reduction of pH (p < 0.001). Equicel® and Tabotamp® increased cytotoxicity significantly in several cell lines (p < 0.01). On OHSC, Tabotamp® and Equicel® led to a stronger and deeper damage to the neuronal tissue than Equitamp® or gauze (p < 0.01). Equicel® increased strongly the number of microglia cells after 24 h (p < 0.001). Microglia cells were not detectable after Tabotamp® treatment, presumably due to an artifact caused by strong pH reduction. In summary, our data imply the use of Equicel®, Tabotamp® or Equitamp® for specific applications in distinct clinical settings depending on their localization or tissue properties.

Cellulose II Aerogel-Based Triboelectric Nanogenerator.

Cellulose-based triboelectric nanogenerators (TENGs) have gained increasing attention. In this study, a novel method is demonstrated to synthesize cellulose-based aerogels and such aerogels are used to fabricate TENGs that can serve as mechanical energy harvesters and self-powered sensors. The cellulose II aerogel is fabricated via a dissolution-regeneration process in a green inorganic molten salt hydrate solvent (lithium bromide trihydrate), where. The as-fabricated cellulose II aerogel exhibits an interconnected open-pore 3D network structure, higher degree of flexibility, high porosity, and a high surface area of 221.3 m2 g-1. Given its architectural merits, the cellulose II aerogel-based TENG presents an excellent mechanical response sensitivity and high electrical output performance. By blending with other natural polysaccharides, i.e., chitosan and alginic acid, electron-donating and electron-withdrawing groups are introduced into the composite cellulose II aerogels, which significantly improves the triboelectric performance of the TENG. The cellulose II aerogel-based TENG is demonstrated to light up light-emitting diodes, charge commercial capacitors, power a calculator, and monitor human motions. This study demonstrates the facile fabrication of cellulose II aerogel and its application in TENG, which leads to a high-performance and eco-friendly energy harvesting and self-powered system.

A prospective multi-center registry concerning the clinical performance of laparoscopic colorectal surgery using an absorbable adhesion barrier (INTERCEED®) made of oxidized regenerated cellulose.

PURPOSE: The aim of this prospective multi-center registry was to evaluate the safety and clinical performance of INTERCEED® in laparoscopic colorectal surgery. METHODS: This study was a prospective, multi-center, single-arm registry wherein patients who received INTERCEED® in laparoscopic colorectal surgery were registered consecutively (UMIN-CTR 00001872). The primary outcome was the incidence rate of postoperative adhesive small intestinal obstruction within 6 months. The secondary outcomes were reoperation related to postoperative bleeding and anastomotic leak, surgical site infection (SSI) and anastomotic leak. RESULTS: Between March 2012 and March 2015, a total of 202 patients were enrolled from six institutions. INTERCEED® was not applied in two patients, so 200 patients were analyzed using the full analysis set population. The incidence rate of postoperative adhesive intestinal obstruction was 1.0% (2/200). The total SSI rate was 3.5% (7/200), the deep incisional SSI rate was 0.0% (0/200), and the organ SSI rate was 0.0% (0/200). The incidence of anastomotic leak was 1.0% (2/200). Reoperation was performed in two cases: one for anastomotic leak and the other as cardiac surgery due to heart disease. CONCLUSIONS: Using INTERCEED® in laparoscopic colorectal surgery is safe and may be useful for preventing postoperative adhesive small intestinal obstruction.

A novel dual-covering method in video-assisted thoracic surgery for pediatric primary spontaneous pneumothorax.

BACKGROUND: Primary spontaneous pneumothorax (PSP) generally occurs in young adults, whereas pediatric PSP is uncommon. It is difficult to source reliable data on pediatric PSP, the management of which is based on guidelines for adult PSP; however, the rate of recurrence after video-assisted thoracoscopic surgery (VATS) for pediatric PSP is reported to be higher. METHODS: We reviewed retrospectively a collective total of 66 surgical cases of a first pneumothorax episode in 46 children under 16 years of age, who were treated at our hospital between February, 2005 and November, 2017. RESULTS: The surgical cases were divided into two groups, depending on how the treated lesions were covered. In the dual-covering (DC) group, the PSP was covered by oxidized regenerated cellulose and polyglycolic acid (8 patients; 13 cases) and in the single-covering (SC) group, the PSP was covered by oxidized regenerated cellulose (38 patients; 53 cases). There was no incidence of recurrence after surgery in the DC group, but 17 cases (32.1%) of recurrence after surgery in the SC group. This difference was significant. CONCLUSION: The DC method prevented the recurrence of PSP more effectively than the SC method after VATS in pediatric patients. Long-term follow-up after VATS for pediatric PSP is also important because of the risk of delayed recurrence.

Efficacy of silicone sheet as a personalized barrier for preventing adhesion reformation after hysteroscopic adhesiolysis of intrauterine adhesions.

PURPOSE: To evaluate the efficacy of silicone sheet as a new type of barrier for preventing adhesion reformation following hysteroscopic adhesiolysis of intrauterine adhesions (IUAs). METHODS: Hysteroscopic adhesiolysis was performed for 36 patients with IUAs. The adhesion reformation rate was retrospectively compared between 26 patients treated with silicone sheet (group 1) and 10 patients treated with an intrauterine device wrapped in oxidized regenerated cellulose as a barrier (group 2). For patients in group 1, a 1-mm-thick silicone sheet was cut to fit the size and shape of the individual uterine cavity as a personalized barrier. RESULTS: The size and shape of each silicone sheet used for patients in group 1 differed significantly. The adhesion reformation rate was significantly lower in group 1 (4/26, 15.4%) than in group 2 (4/10, 40.0%; P = 0.03), although the pregnancy rate (14/20, 70.0% vs. 5/10, 50.0%; P = 0.28) and miscarriage rate (2/14, 14.3% vs. 1/5, 20.0%; P = 0.72) were not significantly different. CONCLUSION: Use of silicone sheets appears to be effective for preventing adhesion reformation following hysteroscopic adhesiolysis of IUAs. This is the first study to investigate the efficacy of silicone sheet used as a personalized barrier for preventing IUAs.

Novel Biobased Textile Fiber from Colombian Agro-Industrial Waste Fiber.

Fique fibers, native to Colombia, are traditionally used for ropes and bags. In the extraction of long fibers for these purposes, the same amount of short fibers is generated; the short fibers are then discarded in the soil or in landfills. This agro-industrial waste is cellulose-rich and can be potentially developed into new biobased products. As an alternative use for these fibers, viscose regenerated fibers with potential applications in the textile industry were developed. Fique waste fibers were pulped (to produce fique cellulose pulp, FCP) using a 3³ design of experiment (DOE) to adjust the variables of the whitening treatment, and DOE analysis showed that time and hydrogen peroxide concentration do not have a significant effect on non-cellulosic remotion, unlike temperature. The behavior of this pulp in the production of viscose was compared against that of commercially available wood cellulose pulp (WCP). FCP showed a suitable cellulose content with a high degree of polymerization, which makes it a viable pulp for producing discontinuous viscose rayon filaments. Both pulps showed the same performance in the production of the viscose dope and the same chemical, thermal, and mechanical behavior after being regenerated.

Subhepatic mass occurrence after using oxidized and regenerated cellulose polymer in laparoscopic cholecystectomy: a case series.

BACKGROUND: Oxidized regenerated cellulose (ORC) is a bioabsorbable surgical hemostatic. We present the first prospective case series of circumscribed mass occurrence after using ORC in laparoscopic cholecystectomy. METHODS: Tabotamp (Ethicon, Inc., Somerville, NJ) in the form of tightly woven knitted patches was used to achieve hemostasis in 83 patients submitted to LC. RESULTS: A subhepatic mass was detected in five patients and radiologic characteristics were described. Abdominal contrast enhanced CT showed a heterogeneous soft-tissue mass. NMR was performed in one patient and showed a T2-weighted hyperintense mass. CONCLUSION: ORC retention after surgery is not uncommon at long-term follow-up. The radiologic characteristics of a suspected ORC retention mass can differentiate it from a neoplastic lesion, so that surgery can be avoided.

[Study on In Vitro Degradation of Oxidized Regenerated Cellulose Absorbable Hemostatic Products].

OBJECTIVE: To study the in vitro degradation of oxidized regenerated cellulose absorbable hemostatic products. METHODS: The morphology of the oxidized regenerated cellulose hemostatic products before and after degradation was observed by FTIR and SEM. The degradation products were determined by GPC and HILIC-ELSD. RESULTS: In the initial stage of degradation, there was a great change in morphology. GPC determined its degradation end point was 10 d; it was determined that its degradation products contained glucose (0.13%) and cellobiose (0.17%) and other components. CONCLUSIONS: A method was established for determining the end point of degradation of oxidized regenerated cellulose, which provided a new idea and reference for the study of the degradation end point.