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Graphene nanoplatelets (UGZ–1004) are emerging as a promising biomaterial in regenerative medicine. This study comprehensively evaluates UGZ–1004, focusing on its physical properties, cytotoxicity, intracellular interactions, and, notably, its effects on mesenchymal stem cells (MSCs). UGZ–1004 was characterized by lateral dimensions and layer counts consistent with ISO standards and demonstrated a high carbon purity of 0.08%. Cytotoxicity assessments revealed that UGZ–1004 is non-toxic to various cell lines, including 3T3 fibroblasts, VERO kidney epithelial cells, BV–2 microglia, and MSCs, in accordance with ISO 10993–5:2020/2023 guidelines. The study focused on MSCs and revealed that UGZ–1004 supports their gene expression alterations related to self-renewal and proliferation. MSCs exposed to UGZ–1004 maintained their characteristic surface markers. Importantly, UGZ–1004 promoted significant upregulation of genes crucial for cell cycle regulation and DNA repair, such as CDK1, CDK2, and MDM2. This gene expression profile suggests that UGZ–1004 can enhance MSC self-renewal capabilities, ensuring robust cellular function and longevity. Moreover, UGZ–1004 exposure led to the downregulation of genes associated with tumor development, including CCND1 and TFDP1, mitigating potential tumorigenic risks. These findings underscore the potential of UGZ–1004 to not only bolster MSC proliferation but also enhance their self-renewal processes, which are critical for effective regenerative therapies. The study highlights the need for continued research into the long-term impacts of graphene nanoplatelets and their application in MSC-based regenerative medicine. [ABSTRACT FROM AUTHOR]

Graphene-based materials have increasingly attracted attention in recent years. It is a material is recognized worldwide due to its numerous applications in several sectors. However, graphene production involves several challenges: scalability, high costs, and high-quality production. This study synthesized graphene-like porous carbon nanosheets (GPCNs) through a thermochemical process under a nitrogen atmosphere using grape bagasse as a precursor. Three temperatures (700, 800, and 900 ºC) of the pyrolysis process were studied. Chemical graphitization and activation were used to form high-specific surface area materials: FeCl3.6H2O(aq) and ZnCl2(s) in a simultaneous activation-graphitization (SAG) method. The materials obtained (GPCN700, GPCN800, and GPCN900) were compared to previously produced chars (C700, C800, and C900). A high specific surface area and total pore volume were obtained for GPCN materials, and GPCN900 presented the highest values: 1062.7 m2g−1 and 0.635 cm3 g−1, respectively. The GPCN and char materials were classified as mesoporous and applied as adsorbents for CO2(g). The GPCN800 presented the best CO2(g) adsorbent, with a CO2(g) adsorption capacity of 168.71 mg g−1. [ABSTRACT FROM AUTHOR]

Due to its toxicity, the presence of Cu(II) ions released in aquatic environments presents a serious threat to the environment and human health. In search of sustainable and low-cost alternatives, there are citrus fruit residues, which are generated in large quantities by the juice industries and can be used to produce activated carbons. Therefore, the physical route was investigated for producing activated carbons to reuse citrus wastes. In this work, eight activated carbons were developed, varying the precursor (orange peel-OP, mandarine peel-MP, rangpur lime peel-RLP, and sweet lime peel-SLP) and the activating agent (CO2 and H2O) to remove Cu(II) ions of the aqueous medium. Results revealed promising activated carbons with a micro-mesoporous structure, a specific surface area of around 400 m2 g–1, and a pore volume of around 0.25 cm3 g–1. In addition, Cu (II) adsorption was favored at pH 5.5. The kinetic study showed that the equilibrium was reached within 60 min removing about 80% of Cu(II) ions. The Sips model was the most suitable for the equilibrium data, providing maximum adsorption capacities (qmS) values of 69.69, 70.27, 88.04, 67.83 mg g–1 for activated carbons (AC-CO2) from OP, MP, RLP, and SLP, respectively. The thermodynamic behavior showed that the adsorption process of Cu(II) ions was spontaneous, favorable, and endothermic. It was suggested that the mechanism was controlled by surface complexation and Cu2+-π interaction. Desorption was possible with an HCl solution (0.5 mol L–1). From the results obtained in this work, it is possible to infer that citrus residues could be successfully converted into efficient adsorbents to remove Cu(II) ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

This work valorizes butiá pomace (Butia capitata) using pyrolysis to prepare CO2 adsorbents. Different fractions of the pomace, like fibers, endocarps, almonds, and deoiled almonds, were characterized and later pyrolyzed at 700 °C. Gas, bio-oil, and biochar fractions were collected and characterized. The results revealed that biochar, bio-oil, and gas yields depended on the type of pomace fraction (fibers, endocarps, almonds, and deoiled almonds). The higher biochar yield was obtained by endocarps (31.9%wt.). Furthermore, the gas fraction generated at 700 °C presented an H2 content higher than 80%vol regardless of the butiá fraction used as raw material. The biochars presented specific surface areas reaching 220.4 m2 g−1. Additionally, the endocarp-derived biochar presented a CO2 adsorption capacity of 66.43 mg g−1 at 25 °C and 1 bar, showing that this material could be an effective adsorbent to capture this greenhouse gas. Moreover, this capacity was maintained for 5 cycles. Biochars produced from butiá precursors without activation resulted in a higher surface area and better performance than some activated carbons reported in the literature. The results highlighted that pyrolysis could provide a green solution for butiá agro-industrial wastes, generating H2 and an adsorbent for CO2. [ABSTRACT FROM AUTHOR]