Synthesis of carbon nanotubes with and without catalyst particles

The initial development of carbon nanotube synthesis revolved heavily around the use of 3d valence transition metals such as Fe, Ni, and Co. More recently, noble metals (e.g. Au) and poor metals (e.g. In, Pb) have been shown to also yield carbon nanotubes. In addition, various ceramics and semiconductors can serve as catalytic particles suitable for tube formation and in some cases hybrid metal/metal oxide systems are possible. All-carbon systems for carbon nanotube growth without any catalytic particles have also been demonstrated. These different growth systems are briefly examined in this article and serve to highlight the breadth of avenues available for carbon nanotube synthesis

Synergistic Combination of Antimicrobial Peptides and Cationic Polyitaconates in Multifunctional PLA Fibers

Combining different antimicrobial agents has emerged as a promising strategy to enhance efficacy and address resistance evolution. In this study, we investigated the synergistic antimicrobial effect of a cationic biobased polymer and the antimicrobial peptide (AMP) temporin L, with the goal of developing multifunctional electrospun fibers for potential biomedical applications, particularly in wound dressing. A clickable polymer with pendent alkyne groups was synthesized by using a biobased itaconic acid building block. Subsequently, the polymer was functionalized through click chemistry with thiazolium groups derived from vitamin B1 (PTTIQ), as well as a combination of thiazolium and AMP temporin L, resulting in a conjugate polymer-peptide (PTTIQ-AMP). The individual and combined effects of the cationic PTTIQ, Temporin L, and PTTIQ-AMP were evaluated against Gram-positive and Gram-negative bacteria as well as Candida species. The results demonstrated that most combinations exhibited an indifferent effect, whereas the covalently conjugated PTTIQ-AMP displayed an antagonistic effect, potentially attributed to the aggregation process. Both antimicrobial compounds, PTTIQ and temporin L, were incorporated into poly(lactic acid) electrospun fibers using the supercritical solvent impregnation method. This approach yielded fibers with improved antibacterial performance, as a result of the potent activity exerted by the AMP and the nonleaching nature of the cationic polymer, thereby enhancing long-term effectiveness.This work was funded by the MICINN (PID2019-104600RB- I00 and PID2021-123553OA-I00), the Agencia Estatal de Investigación (AEI, Spain), and Fondo Europeo de Desarrollo Regional (FEDER, EU) and by CSIC (LINKA20364). A. Chiloeches acknowledges MICIU for his FPU fellowship FPU18/01776. Cesar de la Fuente-Nunez holds a Presidential Professorship at the University of Pennsylvania and acknowl- edges funding from the Procter & Gamble Company, United Therapeutics, a BBRF Young Investigator Grant, the Nemirovsky Prize, Penn Health-Tech Accelerator Award, and the Dean’s Innovation Fund from the Perelman School of Medicine at the University of Pennsylvania. Research reported in this publication was supported by the Langer Prize (AIChE Foundation), the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM138201, and the Defense Threat Reduction Agency (DTRA; HDTRA11810041, HDTRA1-21-1-0014, and HDTRA1-23-1-0001). D. Placha and J. Zagora acknowledge the Doctoral grant competition VSB-Technical University of Ostrava (reg. no. CZ.02.2.69/0.0/0.0/19_073/0016945) with- in the Operational Programme Research, Development and Education, under project DGS/INDIVIDUAL/2020-001 “Development of antimicrobial biobased polymeric material using supercritical fluid technology”

Effect of Milling and Annealing on Carbon-Silver System

PMID = 3050177

Functionalization of Chitosan-Chitin Nanowhiskers Films By Impregnation With Essential Oils Via Supercritical CO2

Herein, we prepared functional chitosan films reinforced with chitin nanocrystals by supercritical solvent impregnation with a variety of essential oils, i.e. mentha, clove, and cinnamon. Two different chitosan film structures were evaluated, smooth and compact films obtained by casting; and highly porous films prepared by lyophilization process. The effect of the film morphology, essential oil impregnation and the presence of chitin nanowhiskers on the properties of the films were extensively investigated by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and tensile testing; while the bioactive functions were evaluated by measuring the antioxidant and antimicrobial activities. It was found that the impregnation of essential oils is much higher in porous films, confering notable antioxidant and antimicrobial activity. The incorporation of chitin nanocrystal does not influence on the impregnation process, and only improves slightly the antioxidant performance, which is clearly appreciable in the case of films obtained by casting with an increase of ca. 35% from chitosan without to samples with 5 wt% of chitin nanowhiskers. Nevertheless, an important enhancement of the mechanical properties, particularly in elastic modulus, is clearly appreciated with the incorporation of chitin nanowhisker into the films, with values of 50% higher in comparison with chitosan without nanowishers. However, the elongation at break and tensile strength values suffer a slight decrease.This work was funded by the Ministerio de Ciencia, Innovación y Universidades (PID2022-13651OB-100), the Agencia Estatal de Investigación (AEI, Spain) and Fondo Europeo de Desarrollo Regional (FEDER, EU). C. Muñoz-Núñez also acknowledges MICINN for her FPI fellowship PRE2020-093596. D. Plachá and J. Zágora acknowledge to the Doctoral grant competition VSB-Technical University of Ostrava, reg. nº. CZ.02.2.69/0.0/0.0/19_073/0016945 within the Operational Programme Research, Development and Education, under project DGS/INDIVIDUAL/2020-001 “Development of antimicrobial biobased polymeric material using supercritical fluid technology”. This work was also financially supported by the European Union under the REFRESH– Research Excellence for Region Sustainability and Hightech Industries project number CZ.10.03.01/00/22_003/0000048 via the Operational Programme Just Transition. This work was also made with the project CZ.02.01.01/00/22_008/0004631, Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union and from the . Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Peer reviewe

Synergistic combination of antimicrobial peptides and cationic polyitaconates in multifunctional PLA fibers

Combining different antimicrobial agents has emerged as a promising strategy to enhance efficacy and address resistance evolution. In this study, we investigated the synergistic antimicrobial effect of a cationic biobased polymer and the antimicrobial peptide (AMP) temporin L, with the goal of developing multifunctional electrospun fibers for potential biomedical applications, particularly in wound dressing. A clickable polymer with pendent alkyne groups was synthesized by using a biobased itaconic acid building block. Subsequently, the polymer was functionalized through click chemistry with thiazolium groups derived from vitamin B1 (PTTIQ), as well as a combination of thiazolium and AMP temporin L, resulting in a conjugate polymer–peptide (PTTIQ-AMP). The individual and combined effects of the cationic PTTIQ, Temporin L, and PTTIQ-AMP were evaluated against Gram-positive and Gram-negative bacteria as well as Candida species. The results demonstrated that most combinations exhibited an indifferent effect, whereas the covalently conjugated PTTIQ-AMP displayed an antagonistic effect, potentially attributed to the aggregation process. Both antimicrobial compounds, PTTIQ and temporin L, were incorporated into poly(lactic acid) electrospun fibers using the supercritical solvent impregnation method. This approach yielded fibers with improved antibacterial performance, as a result of the potent activity exerted by the AMP and the nonleaching nature of the cationic polymer, thereby enhancing long-term effectiveness.Web of Science6114813480