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- 2018
- electromagnetic pulse
- cell proliferation
- cell membrane permeability
- cell response to electromagnetic stress
- apoptosis
- cancer therapy
- necrosis
- Intelligent Medical Engineering
- V.N. Karazin Kharkiv National University
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Understanding Biophotocurrent Generation in Photosynthetic Purple Bacteria
摘要： Establishing an efficient extracellular electron transfer (EET) process between photo-electroactive microorganisms and an electrode surface is critical for the development of photo-bioelectrocatalysis. Soluble and immobilized redox mediators have been applied with purple bacteria Rhodobacter capsulatus for this purpose. However, detailed information on its EET with an electrode surface is not available and, therefore, choice of mediators has been by trial and error. Herein, we experimentally evaluated the capability of different soluble, quinone-based redox mediators to support EET and compared the experimental data with a computational model based on density functional theory calculations. We show that computed electrochemical redox properties of redox mediators in a lipophilic environment correlate to EET processes of Rhodobacter capsulatus, suggesting that intermembrane mediator characteristics are more diagnostic than redox properties of the mediators in an aqueous solution, and that the limiting electron transfer step takes place in the lipophilic membrane of the bacterial cells. This knowledge provides critical insight into designing future mediated bioelectrocatalysis systems.
关键词： quinones,photo-bioelectrocatalysis,lipophilic membrane,Rhodobacter capsulatus,rate determining step,extracellular electron transfer
更新于2025-09-04 15:30:14
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Characterisation of sensor kinase by CD spectroscopy: golden rules and tips
摘要： This is a review that describes the golden rules and tips on how to characterise the molecular interactions of membrane sensor kinase proteins with ligands using mainly circular dichroism (CD) spectroscopy. CD spectroscopy is essential for this task as any conformational change observed in the far-UV (secondary structures (α-helix, β-strands, poly-proline of type II, β-turns, irregular and folding) and near-UV regions [local environment of the aromatic side-chains of amino acid residues (Phe, Tyr and Trp) and ligands (drugs) and prosthetic groups ( porphyrins, cofactors and coenzymes (FMN, FAD, NAD))] upon ligand addition to the protein can be used to determine qualitatively and quantitatively ligand-binding interactions. Advantages of using CD versus other techniques will be discussed. The difference CD spectra of the protein–ligand mixtures calculated subtracting the spectra of the ligand at various molar ratios can be used to determine the type of conformational changes induced by the ligand in terms of the estimated content of the various elements of protein secondary structure. The highly collimated microbeam and high photon flux of Diamond Light Source B23 beamline for synchrotron radiation circular dichroism (SRCD) enable the use of minimal amount of membrane proteins (7.5 mg for a 0.5 mg/ml solution) for high-throughput screening. Several examples of CD titrations of membrane proteins with a variety of ligands are described herein including the protocol tips that would guide the choice of the appropriate parameters to conduct these titrations by CD/SRCD in the best possible way.
关键词： high-throughput screening,circular dichroism,synchrotron radiation circular dichroism,membrane sensor kinase,ligand-binding interactions
更新于2025-09-04 15:30:14
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Comparison of MultiColor fundus imaging and colour fundus photography in the evaluation of epiretinal membrane
摘要： Purpose: To compare MultiColor fundus imaging (MC) and colour fundus photography (CFP) for the evaluation of epiretinal membrane (ERM). Methods: In this retrospective study, 192 eyes (181 patients) that underwent vitrectomy for ERM were imaged using Spectralis optical coherence tomography (for MC) and AFC-210 digital camera (for CFP) 1 week before vitrectomy. Two investigators independently determined the rate of delineability and ERM area for each modality. Results: The intergrader agreement rates for delineability were very high for both image modalities. The rate of delineability of ERM (%) was higher for MC than for CFP, for both investigators [70.8% versus 52.6% and 73.4% versus 53.6% (both p –)]. Epiretinal membrane (ERM) area measurement showed high agreement between investigators for MC (p = 0.466) but di?ered signi?cantly between the investigators for CFP (p –). The ERM area determined on MC was signi?cantly wider than that on CFP for both investigators (p – for investigator 1 and p – for investigator 2). Conclusion: The ERM area is more clearly detectable and widely demarcated in MC than in CFP images. MultiColor imaging (MC) may be more sensitive and accurate for early detection of ERM and ERM area measurement.
关键词： MultiColor imaging,spectral-domain optical coherent tomography,epiretinal membrane,colour fundus photography
更新于2025-09-04 15:30:14
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Achieving enhanced pH sensitivity using capacitive coupling in extended gate FET sensors with various high-K sensing films
摘要： Sensing properties of various high-k sensing membrane, such as SnO2, HfO2, ZrO2, and Ta2O5, in dual gate extended-gate field-effect transistor (EGFET) were investigated. By adapting the dual-gate structure, high sensitivity exceeding the conventional Nernstian limit on sensitivity (59.15 mV/pH at 25 °C) was realized due to capacitive coupling effect. As a results, it was confirmed that dual-gate EGFET with Ta2O5 sensing membrane which has high permittivity shows the highest sensitivity of 478.0 mV/pH as well as excellent hysteresis voltage and drift rate characteristics.
关键词： Glass EG detector,Dual gate poly-Si TFT transducer,High-k membrane,Highest sensitivity,Capacitive coupling,EGFET pH sensor
更新于2025-09-04 15:30:14
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Co-localization coefficients of a target-switchable fluorescent probe can serve as an indicator of mitochondrial membrane potential
摘要： The mitochondrial membrane potential (MMP) definitely reflects mitochondrial function. Thus, it is very essential to found a physical parameter as MMP indicator. At present, available parameters are either fluorescent intensity of monochromatic probes such as rhodamine 123 or a ratio of fluorescent intensity at different wavelengths of dual-color dyes such as JC-1, but the inconvenience in practice as well as serious effect of loading concentrations on experimental results limited their application. To address this concern, herein, we found a reliable and easily obtainable co-localization coefficient (CLC) of a fluorescent probe as new MMP indicator and developed a target switchable fluorescent probe (Mito-Lyso) to attain the aim. Due to intrinsic nature, Mito-Lyso exclusively stains mitochondria with normal MMP and a subsequent decreasing of MMP results in release of some Mito-Lyso. Importantly, the released Mito-Lyso can reversibly transfer between mitochondria and lysosomes. Thus, CLCs of Mito-Lyso and a commercial lysosomal probe (NIR-Lyso) can be MMP-dependent. CLCs gradually increased from 0.20 to 0.8 with the decreasing of MMP and then returned to 0.3 with the recovering of MMP, which better proves that the CLC is a valuable MMP indicator. Furthermore, both the design principle and action mechanism of Mito-Lyso has been explained in detail for the development of this type of probes.
关键词： Mito-Lyso,fluorescent probe,co-localization coefficient,mitochondrial membrane potential,target-switchable
更新于2025-09-04 15:30:14