| 1. |
- Acet, Ömür, et al.
(author)
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Inhibition of bacterial adhesion by epigallocatechin gallate attached polymeric membranes
- 2023
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In: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 0927-7765 .- 1873-4367. ; 221
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Journal article (peer-reviewed)abstract
- Microbial adhesion and formation of biofilms cause a serious problem in several areas including but not limited to food spoilage, industrial corrosion and nosocomial infections. These microbial biofilms pose a serious threat to human health since microbial communities in the biofilm matrix are protected with exopolymeric substances and difficult to eradicate with antibiotics. Hence, the prevention of microbial adhesion followed by biofilm formation is one of the promising strategies to prevent these consequences. The attachment of antimicrobial agents, coatings of nanomaterials and synthesis of hybrid materials are widely used approach to develop surfaces having potential to hinder bacterial adhesion and biofilm formation. In this study, epigallocatechin gallate (EGCG) is attached on p(HEMA-co-GMA) membranes to prevent the bacterial colonization. The attachment of EGCG to membranes was proved by Fourier-transform infrared spectroscopy (FT-IR). The synthesized membrane showed porous structure (SEM), and desirable swelling degree, which are ideal when it comes to the application in biotechnology and biomedicine. Furthermore, EGCG attached membrane showed significant potential to prevent the microbial colonization on the surface. The obtained results suggest that EGCG attached polymer could be used as an alternative approach to prevent the microbial colonization on the biomedical surfaces, food processing equipment as well as development of microbial resistant food packaging systems.
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| 2. |
- Cao, Zhejian, 1991, et al.
(author)
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Synthesis of Metal-Organic Frameworks through Enzymatically Recycled Polyethylene Terephthalate
- 2023
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In: ACS Sustainable Chemistry & Engineering. - 2168-0485. ; 11:43, s. 15506-15512
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Journal article (peer-reviewed)abstract
- Polyethylene terephthalate (PET) as one of the most produced plastics contributes to global waste pollution. Upcycling PET into value-added products therefore is of environmental and economic interest. Terephthalic acid (TPA), the monomer of PET, is a common linker for metal-organic framework (MOF) synthesis; thus, PET-to-MOF upcycling raises much research attention. However, conventional PET-to-MOF upcycling often requires PET depolymerization with strong acids or bases and high temperatures, which can lead to environmental and energy penalties. As an alternative, PETase offers a sustainable approach to depolymerizing PET under mesophilic and mild pH conditions. Here we report UiO-66, MOF-5, and MIL-101 syntheses using enzymatically recycled TPA as linkers. The enzymatically recycled TPA demonstrated low impurity, and the obtained MOFs possessed comparable crystallinity, thermal stability, and surface area. These results reveal the feasibility of MOF synthesis by using enzymatically recycled PET.
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| 3. |
- Chen, Xin, 1980, et al.
(author)
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Graphene Oxide Attenuates Toxicity of Amyloid-β Aggregates in Yeast by Promoting Disassembly and Boosting Cellular Stress Response
- 2023
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In: Advanced Functional Materials. - 1616-3028 .- 1616-301X. ; 33:45
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Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, with the aggregation of misfolded amyloid-β (Aβ) peptides in the brain being one of its histopathological hallmarks. Recently, graphene oxide (GO) nanoflakes have attracted significant attention in biomedical areas due to their capacity of suppressing Aβ aggregation in vitro. The mechanism of this beneficial effect has not been fully understood in vivo. Herein, the impact of GO on intracellular Aβ42 aggregates and cytotoxicity is investigated using yeast Saccharomyces cerevisiae as the model organism. This study finds that GO nanoflakes can effectively penetrate yeast cells and reduce Aβ42 toxicity. Combination of proteomics data and follow-up experiments show that GO treatment alters cellular metabolism to increases cellular resistance to misfolded protein stress and oxidative stress, and reduces amounts of intracellular Aβ42 oligomers. Additionally, GO treatment also reduces HTT103QP toxicity in the Huntington's disease (HD) yeast model. The findings offer insights for rationally designing GO nanoflakes-based therapies for attenuating cytotoxicity of Aβ42, and potentially of other misfolded proteins involved in neurodegenerative pathology.
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| 4. |
- Eswaran, Muthusankar, 1988, et al.
(author)
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A flexible multifunctional electrode based on conducting PANI/Pd composite for non-enzymatic glucose sensor and direct alcohol fuel cell applications
- 2023
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In: Fuel. - : Elsevier BV. - 0016-2361. ; 345
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Journal article (peer-reviewed)abstract
- In this work, we fabricated a flexible, multifunctional polyimide (PI)/Au-polyaniline (PAN)/Pd nanocomposite electrode with excellent electrochemical properties. Structural geometry, morphological views, and functional group analyses indicated that the physicochemical and electrochemical performance of the electrode is based on the strong and synergistic metal-polymer interaction between the conducting PAN and Pd, which ensured high conductivity, rapid response, and high electron transfer rate through more electroactive spots available in the nanocomposite. Here, we demonstrated that the fabricated PI/Au-PAN/Pd electrodes can be successfully used for biomedical sensing of glucose, as well as for energy conversion application, using the oxidation of alcohols such as methanol and ethanol in fuel cells. The electrochemical analysis shows that the flexible sensor (PI/Au-PAN/Pd) has ultra-high sensitivity of 2140 μA/μM.cm2 with a low detection limit of 0.3 μM for glucose. Also, the interference analysis, reproducibility, and stability studies reveal its excellent capability for glucose sensing. Furthermore, the electrode also demonstrates prominent electrocatalytic behavior to the electrooxidation of methanol and ethanol in an alkaline medium with a current density of 3 mA/cm2 and 0.96 mA/cm2 along with good cyclic stability. Thus, this efficient flexible electrocatalyst with good stability, practicability, and reproducibility claims its potential applications in flexible/wearable healthcare diagnostics systems as well as in alternative energy conversion devices.
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| 5. |
- Lanai, Victor, 1990, et al.
(author)
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Differences in interaction of graphene/graphene oxide with bacterial and mammalian cell membranes
- 2023
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In: Nanoscale. - 2040-3372 .- 2040-3364. ; 16:3, s. 1156-1166
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Journal article (peer-reviewed)abstract
- Graphene, a single layer, hexagonally packed two-dimensional carbon sheet is an attractive candidate for diverse applications including antibacterial potential and drug delivery. One of the knowledge gaps in biomedical application of graphene is the interaction of these materials with the cells. To address this, we investigated the interaction between graphene materials (graphene and graphene oxide) and plasma membranes of cells (bacterial and mammalian cells). The interactions of four of the most abundant phospholipids in bacteria and mammalian plasma membranes with graphene materials were studied using density functional theory (DFT) at the atomic level. The calculations showed that the mammalian phospholipids have stronger bonding to each other compared to bacterial phospholipids. When the graphene/graphene oxide sheet is approaching the phospholipid pairs, the bacterial pairs exhibit less repulsive interactions, thereby a more stable system with the sheets was found. We also assembled bacterial and mammalian phospholipids into liposomes. We further observed that the bacterial liposomes and cells let the graphene flakes penetrate the membrane. The differential scanning calorimetry measurements of liposomes revealed that the bacterial liposomes have the lowest heat capacity; this strengthens the theoretical predictions of weaker interaction between the bacterial phospholipids compared to the mammalian phospholipids. We further demonstrated that graphene oxide could be internalized into the mammalian liposomes without disrupting the membrane integrity. The results suggest that the weak bonding among bacteria phospholipids and less repulsive force when graphene materials approach, result in graphene materials interacting differently with the bacteria compared to mammalian cells.
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| 6. |
- More, Pragati Rajendra, et al.
(author)
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Silver Nanoparticles: Bactericidal and Mechanistic Approach against Drug Resistant Pathogens
- 2023
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In: Microorganisms. - : MDPI AG. - 2076-2607. ; 11:2
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Research review (peer-reviewed)abstract
- This review highlights the different modes of synthesizing silver nanoparticles (AgNPs) from their elemental state to particle format and their mechanism of action against multidrug-resistant and biofilm-forming bacterial pathogens. Various studies have demonstrated that the AgNPs cause oxidative stress, protein dysfunction, membrane disruption, and DNA damage in bacteria, ultimately leading to bacterial death. AgNPs have also been found to alter the adhesion of bacterial cells to prevent biofilm formation. The benefits of using AgNPs in medicine are, to some extent, counter-weighted by their toxic effect on humans and the environment. In this review, we have compiled recent studies demonstrating the antibacterial activity of AgNPs, and we are discussing the known mechanisms of action of AgNPs against bacterial pathogens. Ongoing clinical trials involving AgNPs are briefly presented. A particular focus is placed on the mechanism of interaction of AgNPs with bacterial biofilms, which are a significant pathogenicity determinant. A brief overview of the use of AgNPs in other medical applications (e.g., diagnostics, promotion of wound healing) and the non-medical sectors is presented. Finally, current drawbacks and limitations of AgNPs use in medicine are discussed, and perspectives for the improved future use of functionalized AgNPs in medical applications are presented.
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| 7. |
- Pandit, Santosh, 1987, et al.
(author)
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Polymyxin B complexation enhances the antimicrobial potential of graphene oxide
- 2023
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In: Frontiers in cellular and infection microbiology. - 2235-2988. ; 13
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Journal article (peer-reviewed)abstract
- IntroductionThe antibacterial activity of graphene oxide (GO) has been widely explored and tested against various pathogenic bacterial strains. Although antimicrobial activity of GO against planktonic bacterial cells was demonstrated, its bacteriostatic and bactericidal effect alone is not sufficient to damage sedentary and well protected bacterial cells inside biofilms. Thus, to be utilized as an effective antibacterial agent, it is necessary to improve the antibacterial activity of GO either by integration with other nanomaterials or by attachment of antimicrobial agents. In this study, antimicrobial peptide polymyxin B (PMB) was adsorbed onto the surface of pristine GO and GO functionalized with triethylene glycol. MethodsThe antibacterial effects of the resulting materials were examined by evaluating minimum inhibitory concentration, minimum bactericidal concentration, time kill assay, live/dead viability staining and scanning electron microscopy. Results and discussionPMB adsorption significantly enhanced the bacteriostatic and bactericidal activity of GO against both planktonic cells and bacterial cells in biofilms. Furthermore, the coatings of PMB-adsorbed GO applied to catheter tubes strongly mitigated biofilm formation, by preventing bacterial adhesion and killing the bacterial cells that managed to attach. The presented results suggest that antibacterial peptide absorption can significantly enhance the antibacterial activity of GO and the resulting material can be effectively used not only against planktonic bacteria but also against infectious biofilms.
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| 8. |
- Rahimi, Shadi, 1982, et al.
(author)
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Automated Prediction of Bacterial Exclusion Areas on SEM Images of Graphene–Polymer Composites
- 2023
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In: Nanomaterials. - 2079-4991. ; 13:10
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Journal article (peer-reviewed)abstract
- To counter the rising threat of bacterial infections in the post-antibiotic age, intensive efforts are invested in engineering new materials with antibacterial properties. The key bottleneck in this initiative is the speed of evaluation of the antibacterial potential of new materials. To overcome this, we developed an automated pipeline for the prediction of antibacterial potential based on scanning electron microscopy images of engineered surfaces. We developed polymer composites containing graphite-oriented nanoplatelets (GNPs). The key property that the algorithm needs to consider is the density of sharp exposed edges of GNPs that kill bacteria on contact. The surface area of these sharp exposed edges of GNPs, accessible to bacteria, needs to be inferior to the diameter of a typical bacterial cell. To test this assumption, we prepared several composites with variable distribution of exposed edges of GNP. For each of them, the percentage of bacterial exclusion area was predicted by our algorithm and validated experimentally by measuring the loss of viability of the opportunistic pathogen Staphylococcus epidermidis. We observed a remarkable linear correlation between predicted bacterial exclusion area and measured loss of viability (R2 = 0.95). The algorithm parameters we used are not generally applicable to any antibacterial surface. For each surface, key mechanistic parameters must be defined for successful prediction.
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| 9. |
- Rahimi, Shadi, 1982, et al.
(author)
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Ginsenoside Rg3 Reduces the Toxicity of Graphene Oxide Used for pH-Responsive Delivery of Doxorubicin to Liver and Breast Cancer Cells
- 2023
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In: Pharmaceutics. - : MDPI AG. - 1999-4923. ; 15:2
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Journal article (peer-reviewed)abstract
- Doxorubicin (DOX) is extensively used in chemotherapy, but it has serious side effects and is inefficient against some cancers, e.g., hepatocarcinoma. To ameliorate the delivery of DOX and reduce its side effects, we designed a pH-responsive delivery system based on graphene oxide (GO) that is capable of a targeted drug release in the acidic tumor microenvironment. GO itself disrupted glutathione biosynthesis and induced reactive oxygen species (ROS) accumulation in human cells. It induced IL17-directed JAK-STAT signaling and VEGF gene expression, leading to increased cell proliferation as an unwanted effect. To counter this, GO was conjugated with the antioxidant, ginsenoside Rg3, prior to loading with DOX. The conjugation of Rg3 to GO significantly reduced the toxicity of the GO carrier by abolishing ROS production. Furthermore, treatment of cells with GO–Rg3 did not induce IL17-directed JAK-STAT signaling and VEGF gene expression—nor cell proliferation—suggesting GO–Rg3 as a promising drug carrier. The anticancer activity of GO–Rg3–DOX conjugates was investigated against Huh7 hepatocarcinoma and MDA-MB-231 breast cancer cells. GO–Rg3–DOX conjugates significantly reduced cancer cell viability, primarily via downregulation of transcription regulatory genes and upregulation of apoptosis genes. GO–Rg3 is an effective, biocompatible, and pH responsive DOX carrier with potential to improve chemotherapy—at least against liver and breast cancers.
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| 10. |
- Ruan, Hengzhi, 1995, et al.
(author)
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Biomimetic Antibacterial Gelatin Hydrogels with Multifunctional Properties for Biomedical Applications
- 2023
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In: ACS Applied Materials & Interfaces. - 1944-8252 .- 1944-8244. ; 15:47, s. 54249-54249–54265
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Journal article (peer-reviewed)abstract
- A facile novel approach of introducing dopamine and [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide via dopamine-triggered in situ synthesis into gelatin hydrogels in the presence of ZnSO4 is presented in this study. Remarkably, the resulting hydrogels showed 99.99 and 100% antibacterial efficiency against Gram-positive and Gram-negative bacteria, respectively, making them the highest performing surfaces in their class. Furthermore, the hydrogels showed adhesive properties, self-healing ability, antifreeze properties, electrical conductivity, fatigue resistance, and mechanical stability from −100 to 80 °C. The added multifunctional performance overcomes several disadvantages of gelatin-based hydrogels such as poor mechanical properties and limited thermostability. Overall, the newly developed hydrogels show significant potential for numerous biomedical applications, such as wearable monitoring sensors and antibacterial coatings.
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