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Ziesmer J, Sondén I, Venckute Larsson J, Merkl P, Sotiriou GA. Customizable Fabrication of Photothermal Microneedles with Plasmonic Nanoparticles Using Low-Cost Stereolithography Three-Dimensional Printing. ACS APPLIED BIO MATERIALS 2024; 7:4533-4541. [PMID: 38877987 PMCID: PMC11253096 DOI: 10.1021/acsabm.4c00411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 07/16/2024]
Abstract
Photothermal microneedle (MN) arrays have the potential to improve the treatment of various skin conditions such as bacterial skin infections. However, the fabrication of photothermal MN arrays relies on time-consuming and potentially expensive microfabrication and molding techniques, which limits their size and translation to clinical application. Furthermore, the traditional mold-and-casting method is often limited in terms of the size customizability of the photothermal array. To overcome these challenges, we fabricated photothermal MN arrays directly via 3D-printing using plasmonic Ag/SiO2 (2 wt % SiO2) nanoaggregates dispersed in ultraviolet photocurable resin on a commercial low-cost liquid crystal display stereolithography printer. We successfully printed MN arrays in a single print with a translucent, nanoparticle-free support layer and photothermal MNs incorporating plasmonic nanoaggregates in a selective fashion. The photothermal MN arrays showed sufficient mechanical strength and heating efficiency to increase the intradermal temperature to clinically relevant temperatures. Finally, we explored the potential of photothermal MN arrays to improve antibacterial therapy by killing two bacterial species commonly found in skin infections. To the best of our knowledge, this is the first time describing the printing of photothermal MNs in a single step. The process introduced here allows for the translatable fabrication of photothermal MN arrays with customizable dimensions that can be applied to the treatment of various skin conditions such as bacterial infections.
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Dietl S, Merkl P, Sotiriou GA. Prevention of uropathogenic E. coli biofilm formation by hydrophobic nanoparticle coatings on polymeric substrates. RSC APPLIED INTERFACES 2024; 1:667-670. [PMID: 38988413 PMCID: PMC11231686 DOI: 10.1039/d3lf00241a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/20/2024] [Indexed: 07/12/2024]
Abstract
Biofilms in infections are a major health-care challenge and strategies to reduce their formation on medical devices are crucial. Fabrication of superhydrophobic coatings based on hydrocarbon adsorption on rare-earth oxides constitutes an attractive strategy, but their capacity to prevent biofilm formation has not been studied. Here, we explore a scalable and reproducible nanofabrication process for the manufacture of such superhydrophobic coatings and study their antibiofilm activity against clinically-relevant uropathogenic E. coli. These coatings reduce bacterial biofilm formation and prevent biofouling with potential applications preventing medical device related infections.
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Merkl P, Sotiriou GA. Paper-based colorimetric hyperammonemia sensing by controlled oxidation of plasmonic silver nanoparticles. NANOSCALE ADVANCES 2024; 6:2586-2593. [PMID: 38752137 PMCID: PMC11093257 DOI: 10.1039/d4na00021h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/10/2024] [Indexed: 05/18/2024]
Abstract
High concentrations of ammonia in the human body can occur due to a wide variety of underlying causes such as liver cirrhosis and the symptoms of high ammonia concentrations are diffuse and hard to diagnose. The measurement of blood ammonia levels is an important diagnostic tool but is challenging to perform at the patient's bedside. Here, we present a plasmonic Ag nanoparticle-based ammonia sensor which provides a colorimetric optical readout and does not require specialised equipment. This is achieved using plasmonic Ag/SiO2 nanoparticles with the sensing mechanism that in the presence of OCl- they rapidly degrade reducing their plasmonic extinction and losing their characteristic colour. However, if ammonia is also present in the system, it neutralises the OCl- and thus the silver nanoparticles retain their plasmonic colour as can be measured by the naked eye or using a spectrometer. This sensing was further developed to enable measurements with animal serum as well as a implementing a facile "dip-stick" style paper-based sensor.
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Farmand S, Sender V, Karlsson J, Merkl P, Normark S, Henriques-Normark B. STAT3 Deficiency Alters the Macrophage Activation Pattern and Enhances Matrix Metalloproteinase 9 Expression during Staphylococcal Pneumonia. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:69-80. [PMID: 37982695 PMCID: PMC10733582 DOI: 10.4049/jimmunol.2300151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 10/19/2023] [Indexed: 11/21/2023]
Abstract
Staphylococcus aureus is a significant cause of morbidity and mortality in pulmonary infections. Patients with autosomal-dominant hyper-IgE syndrome due to STAT3 deficiency are particularly susceptible to acquiring staphylococcal pneumonia associated with lung tissue destruction. Because macrophages are involved in both pathogen defense and inflammation, we investigated the impact of murine myeloid STAT3 deficiency on the macrophage phenotype in vitro and on pathogen clearance and inflammation during murine staphylococcal pneumonia. Murine bone marrow-derived macrophages (BMDM) from STAT3 LysMCre+ knockout or Cre- wild-type littermate controls were challenged with S. aureus, LPS, IL-4, or vehicle control in vitro. Pro- and anti-inflammatory responses as well as polarization and activation markers were analyzed. Mice were infected intratracheally with S. aureus, bronchoalveolar lavage and lungs were harvested, and immunohistofluorescence was performed on lung sections. S. aureus infection of STAT3-deficient BMDM led to an increased proinflammatory cytokine release and to enhanced upregulation of costimulatory MHC class II and CD86. Murine myeloid STAT3 deficiency did not affect pathogen clearance in vitro or in vivo. Matrix metalloproteinase 9 was upregulated in Staphylococcus-treated STAT3-deficient BMDM and in lung tissues of STAT3 knockout mice infected with S. aureus. Moreover, the expression of miR-155 was increased. The enhanced inflammatory responses and upregulation of matrix metalloproteinase 9 and miR-155 expression in murine STAT3-deficient as compared with wild-type macrophages during S. aureus infections may contribute to tissue damage as observed in STAT3-deficient patients during staphylococcal pneumonia.
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Li H, Merkl P, Sommertune J, Thersleff T, Sotiriou GA. SERS Hotspot Engineering by Aerosol Self-Assembly of Plasmonic Ag Nanoaggregates with Tunable Interparticle Distance. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201133. [PMID: 35670133 PMCID: PMC9353460 DOI: 10.1002/advs.202201133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/23/2022] [Indexed: 06/01/2023]
Abstract
Surface-enhanced Raman scattering (SERS) is a powerful sensing technique. However, the employment of SERS sensors in practical applications is hindered by high fabrication costs from processes with limited scalability, poor batch-to-batch reproducibility, substrate stability, and uniformity. Here, highly scalable and reproducible flame aerosol technology is employed to rapidly self-assemble uniform SERS sensing films. Plasmonic Ag nanoparticles are deposited on substrates as nanoaggregates with fine control of their interparticle distance. The interparticle distance is tuned by adding a dielectric spacer during nanoparticle synthesis that separates the individual Ag nanoparticles within each nanoaggregate. The dielectric spacer thickness dictates the plasmonic coupling extinction of the deposited nanoaggregates and finely tunes the Raman hotspots. By systematically studying the optical and morphological properties of the developed SERS surfaces, structure-performance relationships are established and the optimal hot-spots occur for interparticle distance of 1 to 1.5 nm among the individual Ag nanoparticles, as also validated by computational modeling, are identified for the highest signal enhancement of a molecular Raman reporter. Finally, the superior stability and batch-to-batch reproducibility of the developed SERS sensors are demonstrated and their potential with a proof-of-concept practical application in food-safety diagnostics for pesticide detection on fruit surfaces is explored.
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Merkl P, Zhou S, Zaganiaris A, Shahata M, Eleftheraki A, Thersleff T, Sotiriou GA. Plasmonic Coupling in Silver Nanoparticle Aggregates and Their Polymer Composite Films for Near -Infrared Photothermal Biofilm Eradication. ACS APPLIED NANO MATERIALS 2021; 4:5330-5339. [PMID: 34085032 PMCID: PMC8165696 DOI: 10.1021/acsanm.1c00668] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/27/2021] [Indexed: 05/08/2023]
Abstract
Plasmonic nanoparticles with near-IR (NIR) light absorption are highly attractive in biomedicine for minimally invasive photothermal treatments. However, these optical properties are typically exhibited by plasmonic nanostructures with complex, nonspherical geometries that may prohibit their broad commercialization and further integration into photothermal devices. Herein, we present the single-step aerosol self-assembly of plasmonic nanoaggregates that consisted of spherical silver nanoparticles with tunable extinction from visible to NIR wavelengths. This tunable extinction was achieved by the addition of SiO2 during the flame synthesis of the nanoparticles, which acted as a dielectric spacer between the spherical silver nanoparticles and was also computationally validated by simulating the extinction spectra of similar silver nanoaggregates. These plasmonic nanoaggregates were easily deposited on silicone polymeric surfaces and further encased with a top polymer layer, forming plasmonic photothermal nanocomposite films. The photothermal properties of the NIR nanocomposite films were utilized to eradicate the established biofilms of clinically relevant Escherichia coli and Staphylococcus aureus, with a relationship observed between the final surface temperature and biofilm eradication.
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Merkl P, Long S, McInerney GM, Sotiriou GA. Antiviral Activity of Silver, Copper Oxide and Zinc Oxide Nanoparticle Coatings against SARS-CoV-2. NANOMATERIALS 2021; 11:nano11051312. [PMID: 34067553 PMCID: PMC8155969 DOI: 10.3390/nano11051312] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 01/15/2023]
Abstract
SARS-CoV-2 is responsible for several million deaths to date globally, and both fomite transmission from surfaces as well as airborne transmission from aerosols may be largely responsible for the spread of the virus. Here, nanoparticle coatings of three antimicrobial materials (Ag, CuO and ZnO) are deposited on both solid flat surfaces as well as porous filter media, and their activity against SARS-CoV-2 viability is compared with a viral plaque assay. These nanocoatings are manufactured by aerosol nanoparticle self-assembly during their flame synthesis. Nanosilver particles as a coating exhibit the strongest antiviral activity of the three studied nanomaterials, while copper oxide exhibits moderate activity, and zinc oxide does not appear to significantly reduce the virus infectivity. Thus, nanosilver and copper oxide show potential as antiviral coatings on solid surfaces and on filter media to minimize transmission and super-spreading events while also providing critical information for the current and any future pandemic mitigation efforts.
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Hempel NJ, Merkl P, Asad S, Knopp MM, Berthelsen R, Bergström CAS, Teleki A, Sotiriou GA, Löbmann K. Utilizing Laser Activation of Photothermal Plasmonic Nanoparticles to Induce On-Demand Drug Amorphization inside a Tablet. Mol Pharm 2021; 18:2254-2262. [PMID: 33951909 DOI: 10.1021/acs.molpharmaceut.1c00077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Poor aqueous drug solubility represents a major challenge in oral drug delivery. A novel approach to overcome this challenge is drug amorphization inside a tablet, that is, on-demand drug amorphization. The amorphous form is a thermodynamically instable, disordered solid-state with increased dissolution rate and solubility compared to its crystalline counterpart. During on-demand drug amorphization, the drug molecularly disperses into a polymer to form an amorphous solid at elevated temperatures inside a tablet. This study investigates, for the first time, the utilization of photothermal plasmonic nanoparticles for on-demand drug amorphization as a new pharmaceutical application. For this, near-IR photothermal plasmonic nanoparticles were tableted together with a crystalline drug (celecoxib) and a polymer (polyvinylpyrrolidone). The tablets were subjected to a near-IR laser at different intensities and durations to study the rate of drug amorphization under each condition. During laser irradiation, the plasmonic nanoparticles homogeneously heated the tablet. The temperature was directly related to the rate and degree of amorphization. Exposure times as low as 180 s at 1.12 W cm-2 laser intensity with only 0.25 wt % plasmonic nanoparticles and up to 50 wt % drug load resulted in complete drug amorphization. Therefore, near-IR photothermal plasmonic nanoparticles are promising excipients for on-demand drug amorphization with laser irradiation.
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Merkl P, Aschtgen MS, Henriques-Normark B, Sotiriou GA. Biofilm interfacial acidity evaluation by pH-Responsive luminescent nanoparticle films. Biosens Bioelectron 2020; 171:112732. [PMID: 33120233 PMCID: PMC7116521 DOI: 10.1016/j.bios.2020.112732] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022]
Abstract
Biofilms are dense bacterial colonies that may adhere to the surfaces of medical devices and are major contributors to infections. These colonies are characterized by a self-produced matrix of extracellular polymeric substances (EPS). Bacterial biofilms are difficult to treat with the commonly used antibiotics partially because of their poor diffusion through the EPS and therefore require new targeted strategies to effectively fight them. Biofilms may produce an acidic microenvironment which can be exploited to design such targeted treatment strategies. However, there is currently a lack of high-throughput ways to determine the acidity of biofilms at their interface with the medical device. Here, a novel all-inorganic pH responsive system is developed from luminescent carbonated hydroxyapatite nanoparticles doped with Eu3+ ions which can determine the biofilm acidity fluorometrically due to carbonate removal in acidic environments that directly affects the nanoparticle luminescence. The pH responsive nanoparticles are in-situ deposited during their production onto substrates on which a variety of clinically-relevant biofilms are grown. The acidity of their interfacial (micro)environment depends on the bacterial species and strain even when differences in biofilm biomass are considered.
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Subramanian K, Iovino F, Tsikourkitoudi V, Merkl P, Ahmed S, Berry SB, Aschtgen MS, Svensson M, Bergman P, Sotiriou GA, Henriques-Normark B. Mannose receptor-derived peptides neutralize pore-forming toxins and reduce inflammation and development of pneumococcal disease. EMBO Mol Med 2020; 12:e12695. [PMID: 32985105 PMCID: PMC7645366 DOI: 10.15252/emmm.202012695] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/30/2020] [Accepted: 09/02/2020] [Indexed: 12/30/2022] Open
Abstract
Cholesterol‐dependent cytolysins (CDCs) are essential virulence factors for many human pathogens like Streptococcus pneumoniae (pneumolysin, PLY), Streptococcus pyogenes (streptolysin O, SLO), and Listeria monocytogenes (Listeriolysin, LLO) and induce cytolysis and inflammation. Recently, we identified that pneumococcal PLY interacts with the mannose receptor (MRC‐1) on specific immune cells thereby evoking an anti‐inflammatory response at sublytic doses. Here, we identified the interaction sites between MRC‐1 and CDCs using computational docking. We designed peptides from the CTLD4 domain of MRC‐1 that binds to PLY, SLO, and LLO, respectively. In vitro, the peptides blocked CDC‐induced cytolysis and inflammatory cytokine production by human macrophages. Also, they reduced PLY‐induced damage of the epithelial barrier integrity as well as blocked bacterial invasion into the epithelium in a 3D lung tissue model. Pre‐treatment of human DCs with peptides blocked bacterial uptake via MRC‐1 and reduced intracellular bacterial survival by targeting bacteria to autophagosomes. In order to use the peptides for treatment in vivo, we developed calcium phosphate nanoparticles (CaP NPs) as peptide nanocarriers for intranasal delivery of peptides and enhanced bioactivity. Co‐administration of peptide‐loaded CaP NPs during infection improved survival and bacterial clearance in both zebrafish and mice models of pneumococcal infection. We suggest that MRC‐1 peptides can be employed as adjunctive therapeutics with antibiotics to treat bacterial infections by countering the action of CDCs.
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Iovino F, Merkl P, Spyrogianni A, Henriques-Normark B, Sotiriou GA. Silica-coated phosphorescent nanoprobes for selective cell targeting and dynamic bioimaging of pathogen-host cell interactions. Chem Commun (Camb) 2020; 56:6989-6992. [PMID: 32441283 PMCID: PMC7116283 DOI: 10.1039/d0cc00329h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescence in vitro bioimaging suffers from photobleaching of organic dyes, thus, functional probes with superior photostability are urgently needed. Here, we address this challenge by developing novel silica-coated nanophosphors that may serve as superior luminescent nanoprobes compatible with conventional fluorescence microscopes. We specifically explore their suitability for dynamic in vitro bioimaging of interactions between bacterial pathogens and host cells, and further demonstrate the facile surface functionalization of the amorphous silica layer with antibodies for selective cell targeting.
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Tsikourkitoudi V, Karlsson J, Merkl P, Loh E, Henriques-Normark B, Sotiriou GA. Flame-Made Calcium Phosphate Nanoparticles with High Drug Loading for Delivery of Biologics. Molecules 2020; 25:E1747. [PMID: 32290273 PMCID: PMC7181047 DOI: 10.3390/molecules25071747] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 11/18/2022] Open
Abstract
Nanoparticles exhibit potential as drug carriers in biomedicine due to their high surface-to-volume ratio that allows for facile drug loading. Nanosized drug delivery systems have been proposed for the delivery of biologics facilitating their transport across epithelial layers and maintaining their stability against proteolytic degradation. Here, we capitalize on a nanomanufacturing process famous for its scalability and reproducibility, flame spray pyrolysis, and produce calcium phosphate (CaP) nanoparticles with tailored properties. The as-prepared nanoparticles are loaded with bovine serum albumin (model protein) and bradykinin (model peptide) by physisorption and the physicochemical parameters influencing their loading capacity are investigated. Furthermore, we implement the developed protocol by formulating CaP nanoparticles loaded with the LL-37 antimicrobial peptide, which is a biological drug currently involved in clinical trials. High loading values along with high reproducibility are achieved. Moreover, it is shown that CaP nanoparticles protect LL-37 from proteolysis in vitro. We also demonstrate that LL-37 retains its antimicrobial activity against Escherichia coli and Streptococcus pneumoniae when loaded on nanoparticles in vitro. Therefore, we highlight the potential of nanocarriers for optimization of the therapeutic profile of existing and emerging biological drugs.
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Merkl P, Mooshammer F, Steinleitner P, Girnghuber A, Lin KQ, Nagler P, Holler J, Schüller C, Lupton JM, Korn T, Ovesen S, Brem S, Malic E, Huber R. Ultrafast transition between exciton phases in van der Waals heterostructures. NATURE MATERIALS 2019; 18:691-696. [PMID: 30962556 DOI: 10.1038/s41563-019-0337-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 03/07/2019] [Indexed: 05/12/2023]
Abstract
Heterostructures of atomically thin van der Waals bonded monolayers have opened a unique platform to engineer Coulomb correlations, shaping excitonic1-3, Mott insulating4 or superconducting phases5,6. In transition metal dichalcogenide heterostructures7, electrons and holes residing in different monolayers can bind into spatially indirect excitons1,3,8-11 with a strong potential for optoelectronics11,12, valleytronics1,3,13, Bose condensation14, superfluidity14,15 and moiré-induced nanodot lattices16. Yet these ideas require a microscopic understanding of the formation, dissociation and thermalization dynamics of correlations including ultrafast phase transitions. Here we introduce a direct ultrafast access to Coulomb correlations between monolayers, where phase-locked mid-infrared pulses allow us to measure the binding energy of interlayer excitons in WSe2/WS2 hetero-bilayers by revealing a novel 1s-2p resonance, explained by a fully quantum mechanical model. Furthermore, we trace, with subcycle time resolution, the transformation of an exciton gas photogenerated in the WSe2 layer directly into interlayer excitons. Depending on the stacking angle, intra- and interlayer species coexist on picosecond scales and the 1s-2p resonance becomes renormalized. Our work provides a direct measurement of the binding energy of interlayer excitons and opens the possibility to trace and control correlations in novel artificial materials.
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Henning DF, Merkl P, Yun C, Iovino F, Xie L, Mouzourakis E, Moularas C, Deligiannakis Y, Henriques-Normark B, Leifer K, Sotiriou GA. Luminescent CeO 2:Eu 3+ nanocrystals for robust in situ H 2O 2 real-time detection in bacterial cell cultures. Biosens Bioelectron 2019; 132:286-293. [PMID: 30884315 PMCID: PMC6629545 DOI: 10.1016/j.bios.2019.03.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 12/29/2022]
Abstract
Hydrogen peroxide (H2O2) quantification in biomedicine is valuable as inflammation biomarker but also in assays employing enzymes that generate or consume H2O2 linked to a specific biomarker. Optical H2O2 detection is typically performed through peroxidase-coupled reactions utilizing organic dyes that suffer, however, from poor stability/reproducibility and also cannot be employed in situ in dynamic complex cell cultures to monitor H2O2 levels in real-time. Here, we utilize enzyme-mimetic CeO2 nanocrystals that are sensitive to H2O2 and study the effect of H2O2 presence on their electronic and luminescent properties. We produce and dope with Eu3+ these particles in a single-step by flame synthesis and directly deposit them on Si and glass substrates to fabricate nanoparticle layers to monitor in real-time and in situ the H2O2 concentrations generated by Streptococcus pneumoniae clinical isolates. Furthermore, the small CeO2:Eu3+ nanocrystals are combined in a single-step with larger, non-responsive Y2O3:Tb3+ nanoparticles during their double-nozzle flame synthesis to engineer hybrid luminescent nanoaggregates as ratiometric robust biosensors. We demonstrate the functionality of these biosensors by monitoring their response in the presence of a broad range of H2O2 concentrations in vitro from S. pneumoniae, highlighting their potential for facile real-time H2O2 detection in vitro in cell cultures.
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Košata J, Merkl P, Teeratchanan P, Hermann A. Stability of Hydrogen Hydrates from Second-Order Møller-Plesset Perturbation Theory. J Phys Chem Lett 2018; 9:5624-5629. [PMID: 30179509 DOI: 10.1021/acs.jpclett.8b02274] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The formation of gas hydrates and clathrates critically depends on the interaction between the host water network and the guest gas species. Density functional calculations can struggle to quantitatively capture these dispersion-type interactions. Here, we report wave function-based calculations on hydrogen hydrates that combine periodic Hartree-Fock with a localized treatment of electronic correlation. We show that local second-order Møller-Plesset perturbation theory (LMP2) reproduces the stability of the different filled-ice-like hydrates in excellent agreement with experimental data. In contrast to various dispersion-corrected density functional theory implementations, LMP2 correctly identifies the pressures needed to stabilize the C0, C1, and C2 hydrates and does not find a spurious region of stability for an ice-Ih-based dihydrate. Our results suggest that LMP2 or similar approaches can provide quantitative insights into the mechanisms of formation and eventual decomposition of molecular host-guest compounds.
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