| 1. |
- Afewerki, Samson, et al.
(författare)
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Advances in dual functional antimicrobial and osteoinductive biomaterials for orthopaedic applications
- 2020
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Ingår i: Nanomedicine. - : Elsevier BV. - 1549-9634 .- 1549-9642. ; 24
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Forskningsöversikt (refereegranskat)abstract
- A vast growing problem in orthopaedic medicine is the increase of clinical cases with antibiotic resistant pathogenic microbes, which is predicted to cause higher mortality than all cancers combined by 2050. Bone infectious diseases limit the healing ability of tissues and increase the risk of future injuries due to pathologic tissue remodelling. The traditional treatment for bone infections has several drawbacks and limitations, such as lengthy antibiotic treatment, extensive surgical interventions, and removal of orthopaedic implants and/or prosthesis, all of these resulting in long-term rehabilitation. This is a huge burden to the public health system resulting in increased healthcare costs. Current technologies e.g. co-delivery systems, where antibacterial and osteoinductive agents are delivered encounter challenges such as site-specific delivery, sustained and prolonged release, and biocompatibility. In this review, these aspects are highlighted to promote the invention of the next generation biomaterials to prevent and/or treat bone infections and promote tissue regeneration.
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| 2. |
- Afewerki, Samson, 1985-, et al.
(författare)
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Efficient Heterogeneous Palladium-Catalyzed Transfer Hydrogenolysis of Benzylic Alcohols by Formic Acid
- 2020
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Ingår i: Synthesis (Stuttgart). - : Georg Thieme Verlag KG. - 0039-7881 .- 1437-210X. ; 52:16, s. 2330-2336
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Tidskriftsartikel (refereegranskat)abstract
- An efficient heterogeneous palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols using formic acid as hydrogen source has been developed. The resulting hydrocarbon products were obtained in excellent yields. Moreover, the system exhibits high chemoselectivity, reacting only with the hydroxy groups in the presence of other functional groups, and excellent recyclability.
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| 3. |
- Afewerki, Samson, 1985-, et al.
(författare)
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Synthesis of amides and amines from aldehydes or ketones by heterogeneous metal catalysis
- 2019
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Patent (populärvet., debatt m.m.)abstract
- A mild and efficient synthesis of primary amines and amides from aldehydes or ketones using a heterogeneous metal catalyst and amine donor is disclosed. The initial heterogeneous metal-catalyzed reaction between the carbonyl and the amine donor components is followed by the addition of a suitable acylating agent component in one-pot, thus providing a catalytic one-pot three-component synthesis of amides. Integration of enzyme catalysis allows for eco-friendly one-pot co-catalytic synthesis of amides from aldehyde and ketone substrates, respectively. The process can be applied to asymmetric synthesis or to the co-catalytic one-pot three-component synthesis of capsaicin and its analogues from vanillin or vanillyl alcohol. A co-catalytic reductive amination/dynamic kinetic resolution (dkr) relay sequence for the asymmetric synthesis of optically active amides from ketones is disclosed. Implementation of a catalytic reductive amination/kinetic resolution (kr) relay sequence produces the corresponding optically active amide product and optical active primary amine product with the opposite stereochemistry from the starting ketones.
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| 6. |
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| 7. |
- Blasi-Romero, Anna, et al.
(författare)
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In Vitro Investigation of Thiol-Functionalized Cellulose Nanofibrils as a Chronic Wound Environment Modulator
- 2021
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- There is currently a huge need for new, improved therapeutic approaches for the treatment of chronic wounds. One promising strategy is to develop wound dressings capable of modulating the chronic wound environment (e.g., by controlling the high levels of reactive oxygen species (ROS) and proteases). Here, we selected the thiol-containing amino acid cysteine to endow wood-derived cellulose nanofibrils (CNF) with bioactivity toward the modulation of ROS levels and protease activity. Cysteine was covalently incorporated into CNF and the functionalized material, herein referred as cys-CNF, was characterized in terms of chemical structure, degree of substitution, radical scavenging capacity, and inhibition of protease activity. The stability of the thiol groups was evaluated over time, and an in vitro cytotoxicity study with human dermal fibroblasts was performed to evaluate the safety profile of cys-CNF. Results showed that cys-CNF was able to efficiently control the activity of the metalloprotease collagenase and to inhibit the free radical DPPH (1,1-Diphenyl-2-picrylhydrazyl radical), activities that were correlated with the presence of free thiol groups on the nanofibers. The stability study showed that the reactivity of the thiol groups challenged the bioactivity over time. Nevertheless, preparing the material as an aerogel and storing it in an inert atmosphere were shown to be valid approaches to increase the stability of the thiol groups in cys-CNF. No signs of toxicity were observed on the dermal fibroblasts when exposed to cys-CNF (concentration range 0.1-0.5 mg/mL). The present work highlights cys-CNF as a promising novel material for the development of bioactive wound dressings for the treatment of chronic wounds.
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| 8. |
- Blasi Romero, Anna, et al.
(författare)
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KR-12 derivatives endow nanocellulose with antibacterial and anti-inflammatory properties : Role of conjugation chemistry
- 2023
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Ingår i: ACS Applied Materials and Interfaces. - 1944-8244 .- 1944-8252. ; 15:20, s. 24186-24196
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Tidskriftsartikel (refereegranskat)abstract
- This work combines the wound-healing-related properties of the host defense peptide KR-12 with wood-derived cellulose nanofibrils (CNFs) to obtain bioactive materials, foreseen as a promising solution to treat chronic wounds. Amine coupling through carbodiimide chemistry, thiol-ene click chemistry, and Cu(I)-catalyzed azide-alkyne cycloaddition were investigated as methods to covalently immobilize KR-12 derivatives onto CNFs. The effects of different coupling chemistries on the bioactivity of the KR12-CNF conjugates were evaluated by assessing their antibacterial activities against Escherichia coli and Staphylococcus aureus. Potential cytotoxic effects and the capacity of the materials to modulate the inflammatory response of lipopolysaccharide (LPS)-stimulated RAW 245.6 macrophages were also investigated. The results show that KR-12 endowed CNFs with antibacterial activity against E. coli and exhibited anti-inflammatory properties and those conjugated by thiol-ene chemistry were the most bioactive. This finding is attributed to a favorable peptide conformation and accessibility (as shown by molecular dynamics simulations), driven by the selective chemistry and length of the linker in the conjugate. The results represent an advancement in the development of CNF-based materials for chronic wound care. This study provides new insights into the effect of the conjugation chemistry on the bioactivity of immobilized host defense peptides, which we believe to be of great value for the use of host defense peptides as therapeutic agents.
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| 10. |
- Burgos-Moron, Estefania, et al.
(författare)
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In Vitro Anticancer Activity and Mechanism of Action of an Aziridinyl Galactopyranoside
- 2022
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Ingår i: Biomedicines. - : MDPI AG. - 2227-9059. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- We recently screened a series of new aziridines beta-D-galactopyranoside derivatives for selective anticancer activity and identified 2-methyl-2,3-[N-(4-methylbenzenesulfonyl)imino]propyl 2,3-di-O-benzyl-4,6-O-(S)-benzylidene-beta-D-galactopyranoside (AzGalp) as the most promising compound. In this article, we explore the possible mechanisms involved in the cytotoxicity of this aziridine and evaluate its selective anticancer activity using cancer cells and normal cells from a variety of tissues. Our data show that AzGalp induces DNA damage (comet assay). Cells deficient in the nucleotide excision repair (NER) pathway were hypersensitive to the cytotoxicity of this compound. These results suggest that AzGalp induces bulky DNA adducts, and that cancer cells lacking a functional NER pathway may be particularly vulnerable to the anticancer effects of this aziridine. Several experiments revealed that neither the generation of oxidative stress nor the inhibition of glycolysis played a significant role in the cytotoxicity of AzGalp. Combinations of AzGalp with oxaliplatin or 5-fluorouracil slightly improved the ability of both anticancer drugs to selectively kill cancer cells. AzGalp also showed selective cytotoxicity against a panel of malignant cells versus normal cells; the highest selectivity was observed for two acute promyelocytic leukemia cell lines. Additional preclinical studies are necessary to evaluate the anticancer potential of AzGalp.
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