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Surface Coatings Modulate the Differences in the Adhesion Forces of Eukaryotic and Prokaryotic Cells as Detected by Single Cell Force Microscopy
摘要： Single cell force microscopy was used to investigate the maximum detachment force (MDF) of primary neuronal mouse cells (PNCs), osteoblastic cells (MC3T3), and prokaryotic cells (Staphylococcus capitis subsp. capitis) from different surfaces after contact times of 1 to 5 seconds. Positively charged silicon nitride surfaces were coated with positively charged polyethyleneimine (PEI) or poly-D-lysine. Laminin was used as the second coating. PEI induced MDFs of the order of 5 to 20 nN, slightly higher than silicon nitride did. Lower MDFs (1 to 5 nN) were detected on PEI/laminin with the lowest on PDL/laminin. To abstract from the individual cell properties, such as size, and to obtain cell type-specific MDFs, the MDFs of each cell on the different coatings were normalized to the silicon nitride reference for the longest contact time. The differences in MDF between prokaryotic and eukaryotic cells were generally of similar dimensions, except on PDL/laminin, which discriminated against the prokaryotic cells. We explain the lower MDFs on laminin by the spatial prevention of the electrostatic cell adhesion to the underlying polymers. However, PEI can form long flexible loops protruding from the surface-bound layer that may span the laminin layer and easily bind to cellular surfaces and the small prokaryotic cells. This was reflected in increased MDFs after two-second contact times on silicon nitride, whereas the two-second values were already observed after one second on PEI or PEI/laminin. We assume that the electrostatic charge interaction with the PEI loops is more important for the initial adhesion of the smaller prokaryotic cells than for eukaryotic cells.
关键词： prokaryotic cells,poly-D-lysine,silicon nitride,laminin,cell adhesion,single cell force microscopy,surface coatings,polyethyleneimine,eukaryotic cells,maximum detachment force
更新于2025-11-21 11:24:58
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Label-free fluorescent discrimination and detection of epinephrine and dopamine based on bioinspired in situ copolymers and excitation wavelength switch
摘要： A simple and label-free fluorescence turn-on method is proposed for the discrimination and detection of epinephrine (Ep) and dopamine (DA) via polyethyleneimine (PEI)-initiated in situ copolymerization and excitation wavelength switch. The PEI solution in the presence of Ep, DA and the mixture of Ep and DA are denoted as PEp-PEI, PDA-PEI and MEptDA, respectively. In this study, PEI aqueous solution medium initiates the auto-oxidization of Ep and DA and the bioinspired copolymerization. These resultant copolymers emit yellow-green fluorescence color with a fluorescence emission maximum at 515 nm. Interestingly, these fluorescent copolymers exhibit distinct different excitation spectra, although Ep and DA are structurally very similar. PDA-PEI exhibits only one excitation peak at 385 nm, and PEp-PEI shows dual-excitation mode with two significant excitation peaks at 328 nm and 405 nm, respectively. MEptDA also shows dual-excitation mode with two excitation peaks at 330 nm and 395 nm, respectively. Thus, individual Ep, DA, and their mixture can be discriminated based on the different excitation spectral shapes and peak locations of PEp-PEI, PDA-PEI and MEptDA. Furthermore, the quantitative analysis of Ep and DA in mixture can also be achieved by switching excitation wavelength between 330 and 395 nm and monitoring the fluorescence emission intensity of MEptDA at 515 nm. The fluorescence intensity of MEptDA only related to the concentration of Ep when excited at 330 nm. Moreover, the concentration of DA can also be calculated by subtracting the fluorescence intensity of PEp-PEI from the total fluorescence intensity when excited at 395 nm. The resultant method has been used to simultaneously detect Ep and DA in human urine samples. The proposed fluorescence system is facile, eco-friendly, low-cost, and time-saving, and also provides a new and simple path for discriminating analogues.
关键词： Epinephrine,Fluorescence turn-on,Polyethyleneimine,Dopamine,Simultaneous discrimination and detection
更新于2025-09-23 15:23:52
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Reproducible Dry Stamping Transfer of PEDOT:PSS Transparent Top Electrode for Flexible Semi-transparent Metal Halide Perovskite Solar Cells
摘要： A semi-transparent flexible metal halide perovskite (MHP) solar cells were demonstrated by reproducible dry stamping transfer of a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS, PH1000) transparent flexible top-electrode onto a poly(ethylene terephthalate) (PET)/ITO/PEDOT:PSS (AI4083)/MHP/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The reproducible transfer of the PEDOT:PSS top electrode was enabled by the modification of PEDOT:PSS with poly(ethylene imine) (PEI)/2-methoxyethanol (2-MEA) solution. In addition, the PEI/2-MEA modification to PEDOT:PSS resulted in the improved conductivity and the reduced work function of top electrode. Therefore, we could fabricate highly efficient flexible semi-transparent MHP solar cells with > 13 % (active area = 1 cm2) of power conversion efficiency.
关键词： stamping transfer,perovskite solar cells,PEDOT:PSS,flexible,polyethyleneimine,semi-transparent
更新于2025-09-23 15:19:57
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Ionic Self-Assembled Luminescent Nanospheres from Cationic Polyelectrolyte and Eu-Containing Polyoxometalate
摘要： Using the ionic self-assembly (ISA) strategy to combine Eu-containing polyoxometalates (Eu-POMs) and organic molecules mainly through noncovalent electrostatic interactions can protect Eu-POMs from solvent quenching of luminescence and enhance their processability. For this reason, a cationic polyelectrolyte, branched polyethyleneimine (PEI), and a Eu-POM, Na9(EuW10O36)·32H2O (EuW10), were used here to construct luminescence-enhanced spherical aggregates with diameters ranging from 50 to 200 nm. At a fixed concentration of EuW10, the phase behavior and luminescence properties of the mixture could be modulated by the PEI concentration. Such ISA-induced aggregates could effectively shield water molecules and result in better photophysical properties. Compared to bare EuW10, the absolute quantum yield and lifetime of luminescence for aggregates increased 10 and 5 times, respectively. Meanwhile, the sensitivity of the EuW10 coordination structure to the environment made it possible for obtained aggregates being used to detect either copper cations or permanganate anions due to their strong specific quenching effects to luminescence. Such a new type of luminescent soft material not only provided a reference for exploring the luminescence enhancement mechanism of lanthanide through self-assembly in aqueous solution but also exhibited potential in detection by luminescence analysis.
关键词： polyoxometalates,permanganate detection,polyethyleneimine,ionic self-assembly,copper detection,luminescence enhancement,luminescent nanospheres
更新于2025-09-23 15:19:57
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A molybdenum disulfide quantum dots-based ratiometric fluorescence strategy for sensitive detection of epinephrine and ascorbic acid
摘要： In this paper, a novel and sensitive ratiometric fluorescence strategy for the detection of epinephrine (EP) and ascorbic acid (AA) was established based on the fluorescence resonance energy transfer (FRET) between the molybdenum disulfide quantum dots (MQDs) and the fluorescent oxidative polymerization product (PEP-PEI) of EP in polyethyleneimine (PEI) aqueous solution. The continuous formation of PEP-PEI can lead to the fluorescence quenching of MQDs at 414 nm while the fluorescence of PEP-PEI at 522 nm gradually increased. The introduction of AA can inhibit the oxidative polymerization process of EP due to the strong reducibility of AA, resulting in the fluorescence recovery of MQDs at 414 nm and the fluorescence decreasing of PEP-PEI at 522 nm. Therefore, EP and AA can be monitored by measuring the ratio of the fluorescence intensities at 522 nm and 414 nm. A good linear calibration of I522/I414 versus EP and AA concentrations were obtained within 0.2e40 mM and 0.5e40 mM, respectively. And the detection limit was 0.05 mM for EP and 0.2 mM for AA. Furthermore, the developed ratiometric fluorescence method with high sensitivity and selectivity was applied for EP in human urine samples and AA in human serum samples determination with satisfactory results obtained.
关键词： Epinephrine,Polyethyleneimine,Ascorbic acid,MoS2 quantum dots,Ratiometric fluorescence
更新于2025-09-19 17:13:59
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A Review on Additives for Halide Perovskite Solar Cells
摘要： In this assay, a new polyethyleneimine-gold nanoparticles-protoporphyrin cobalt (II) (PEI-AuNPs-CoPP) nanocomposite was synthesized by a simple method under mild conditions, and it was used to fabricate an electrochemical sensor for the detection of hydrogen peroxide (H2O2). The structures of nanomaterials were characterized by fourier transform infrared (FTIR) spectroscopy and ultraviolet visible spectrometry (UV–vis). Under the optimum condition, the current intensity was linearly related to H2O2 concentration in the range of 50–280 aM (R2 = 0.9932). It's worth mentioning that a lower detection limit of 7.26 aM was obtained at a signal-to-noise rate of 3. In addition, the experiments showed that ascorbic acid (AA), uric acid (UA) and glucose (Glu) had little effect on the determination of H2O2. The sensor had a good analytical performance for the determination of H2O2 in human serum samples. These results suggested that the proposed PEI-AuNPs-CoPP nanocomposites had practical application prospect in biological sample analysis and clinical diagnosis.
关键词： Hydrogen peroxide sensor,Polyethyleneimine,Gold nanoparticle,Protoporphyrin cobalt (II)
更新于2025-09-19 17:13:59
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Electrical Conduction and Luminescence for Inverted-Type Organic Light-Emitting Diodes with Polyethyleneimine
摘要： Organic light-emitting diodes (OLEDs) have showed the unique potentials of display by bendable, foldable and storable panels. In general, since OLEDs consisted of multi organic layers, their electrical conduction would be complicated. Aluminum quinoline (Alq3) was a classical and famous fluorescent material. We studied the conduction properties of inverted Alq3-bilayer OLEDs. Since the barrier height of electron injection from ITO cathode to Alq3 was higher than that from LiF/Al, electrons were little injected into Alq3 and the current density in the absence of EL was controlled by holes. In the specimen using polyethyleneimine as an injection layer, the current density and hole injection were influenced by electron injection for the current continuity. Despite that holes could arrive at the counter cathode through Alq3, the recombination zone was located near a hole transport layer as the conventional bilayer OLED. It was suggested that the carrier transport in an organic layer depends on both carrier injections.
关键词： Polyethyleneimine,Organic light-emitting diode,Inverted structure,Carrier injection
更新于2025-09-16 10:30:52
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Influence of PEIE interlayer on detectivity of red-light sensitive organic non-fullerene photodetectors with reverse structure
摘要： In this work we analyse an influence of 80 % ethoxylated polyethyleneimine (PEIE) interlayer modifying the ITO electrode work function on the detectivity and time response of the red-light sensitive photodetectors based on donor-acceptor copolymer HFQx-T (where HFQx stands for hexafluoroquinoxaline acceptor units, and T for benzodithiophene derivative donor blocks) blended with acceptor ITIC (with indacenodithieno[3,2-b]thiophene as central donor unit and 2-(3-oxo-2,3-dihydroinden-1-ylidene) malononitrile as acceptor end groups). Modification of ITO electrode by PEIE interlayer allows to construct the photodiode with reversed structure which results in low dark current and high detectivity of the photodetector. The 3.5 nanometres thick PEIE interlayer causes strong reduction of the dark current in comparison to the dark current measured in classical photodiode structure; this allowed to obtain remarkably high detectivity, exceeding 2×1013 Jones. However, a presence of the PEIE interlayer has significantly lengthen the photodiode time response. We demonstrate that when designing the photodiodes with reversed structure, one should consider compromise between the required detectivity and the time response of the photodetector.
关键词： organic photodiode with reverse structure,ethoxylated polyethyleneimine,photodetector detectivity,photodetector time response,PEIE,organic photodetector
更新于2025-09-12 10:27:22
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99mTc-Labeled Polyethyleneimine-Entrapped Gold Nanoparticles with pH-Responsive Charge Conversion Property for Enhanced Dual Mode SPECT/CT Imaging of Cancer Cells
摘要： Development of tumor dual mode contrast agent is still a great challenge due to the relative low accumulation at tumor site, which result in the poor imaging efficiency. In this study, we constructed functional technetium-99m (99mTc) labeled polyethyleneimine (PEI)-entrapped gold nanoparticles (Au PENs) with pH-responsive charge conversion property for enhanced single photon emission computed tomography (SPECT)/computed tomography (CT) dual mode imaging of cancer cells. PEI with amine functional groups (PEI.NH2) was successively modified with monomethyl ether and carboxyl functionalized polyethylene glycol (mPEG-COOH), maleimide and succinimidyl valerate functionalized PEG (MAL-PEG-SVA), diethylenetriaminepentaacetic dianhydride (DTPA), and fluorescein isothiocyanate (FI), and used to entrapped gold nanoparticles inside, followed by conjugation with the alkoxyphenyl acylsulfonamide (APAS) through the PEG maleimide, acetylation of the PEI leftover surface amines and 99mTc labeling. The created nanosystem with the mean Au core diameter of 3.3 nm and with a narrow size distribution displays an excellent colloidal stability and desired cytocompatibility in the investigated Au concentration range. Due to the fact that the attached APAS moieties are responsive to pH, the functionalized Au PENs with a neutral surface charge can switch to be positively charged under slightly acidic pH condition, which could improve the cellular uptake by cancer cells. With these properties, the developed functionalized Au PENs could achieve enhanced dual mode SPECT/CT imaging of cancer cells in vitro. The constructed PEI-based nanodevices may be adopted as an excellent dual mode contrast agent for SPECT/CT imaging of cancer cells of different types.
关键词： technetium-99m,gold nanoparticles,SPECT imaging,CT imaging,pH-responsive charge conversion,polyethyleneimine
更新于2025-09-12 10:27:22
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Highly flexible and solution-processed organic photodiodes and their application to optical luminescent oxygen sensors
摘要： We present a solution-processed flexible organic photodiode (f-OPD) with a bulk heterojunction (BHJ) structure based on a blend of poly (3-hexylthiophene-2,5-diyl) and 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61 (P3HT:PCBM). We used Cs2CO3-doped polyethyleneimine ethoxylated (d-PEIE) as the electron transport layer (ETL) material, which significantly improved the electron injection properties of the f-OPD. Compared with f-OPDs with conventional ETL materials such as Cs2CO3, the external quantum efficiency (EQE) of the d-PEIE-based f-OPD was highly improved. Analytical results showed that the d-PEIE reduced the work function of the cathode, thereby facilitating the efficiency of electron injection from the active layer (AL) to the cathode of the f-OPD. In addition, after 10,000 cycles of tensile bending at a bending radius of 5 mm, the normalized ID variation (ID/ID0) in the d-PEIE-based f-OPD remained above 90%, indicating an excellent device bending stability. Finally, f-OPD-based luminescent oxygen (O2) sensors were successfully fabricated consisting of a photoluminescent O2 sensing film, a light source, and an f-OPD. The O2 sensors based on d-PEIE-based f-OPDs showed the highest photocurrent and O2 sensitivity in relation to the O2 concentration compared with O2 sensors based on f-OPDs with conventional ETL materials.
关键词： organic photodiodes,electron transport layer,Cs2CO3,polyethyleneimine ethoxylated
更新于2025-09-10 09:29:36