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Quantum Dots as Promising Theranostic Tools Against Amyloidosis: A Review
摘要： Amyloids are highly ordered beta sheet rich stable protein aggregates, which have been found to play a significant role in the onset of several degenerative diseases such as Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, Type II diabetes mellitus and so on. Aggregation of proteins leading to amyloid fibril formation via intermediate(s), is thought to be a nucleated condensation polymerization process associated with many pathological conditions. There has been extensive research to identify inhibitors of these disease oriented aggregation processes. In recent times, quantum dots, with their unique physico-chemical properties have grabbed the attention of scientific community due to its applications in medical sciences. Quantum dots are nano-particles usually made of semiconductor materials which emit fluorescence upon radiation. The wavelength of fluorescence emission varies with changes in size of quantum dots. Several studies have reported significant inhibitory effects of these quantum dots towards amyloidogenesis, thereby presenting themselves as promising candidates against amyloidosis. Further, studies have also revealed amyloid detection capacity of quantum dots with sensitivity and specificity better than conventional probes. In the current review, we will discuss the various effects of quantum dots on protein aggregation pathways, their mechanism of actions and their potentials as effective therapeutics against amyloidosis.
关键词： quantum dots,Protein quality control,amyloid,degenerative disorders,small molecule inhibitors,aggregates
更新于2025-09-16 10:30:52
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PEGylation of protein-imprinted nanocomposites sandwiching CdTe quantum dots with enhanced fluorescence sensing selectivity
摘要： Fluorescent sensors combining the selective recognition of protein molecularly imprinted polymers (MIPs) and the fluorescent sensing of quantum dots (QDs) have been studied considerably, but their fluorescence sensing selectivity for the target proteins remains to be increased. Herein, we propose a strategy for increasing the sensing selectivity by post-imprinting PEGylation of surface protein-imprinted nanocomposites with embedded QDs. With bovine hemoglobin (BHb) as a model protein template, protein MIP nanolayers were anchored over the CdTe QD decorated SiO2 nanoparticles by the sol–gel process using aminopropyltriethoxy silane and tetraethoxysilicane. PEG chains were then grafted onto the surface of the imprinted nanostructures via the nucleophilic reaction of the surface amine groups with N-hydroxysuccinimide ester-terminal methoxy-PEG, followed by template removal. The resultant PEGylated sensors showed significantly improved aqueous dispersion stability compared with the non-PEGylated controls. More importantly, such PEGylation greatly increased the fluorescence response selectivity, with the Stern–Volmer equation based imprinting factor increasing from 2.7 to 5.4. The PEGylated sensors were applied to determine BHb in bovine serum samples with satisfactory recoveries at three spiking levels ranging from 94.3 to 103.7%, indicating their potential application in real samples.
关键词： PEGylation,Fluorescent sensors,Protein molecularly imprinted polymers,Quantum dots,Stern–Volmer equation,Bovine serum samples,Sol–gel process,Bovine hemoglobin
更新于2025-09-16 10:30:52
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Phosphorylation at Serine 21 in G protein‐coupled receptor kinase 1 (GRK1) is required for normal kinetics of dark adaption in rod but not cone photoreceptors
摘要： Timely recovery of the light response in photoreceptors requires efficient inactivation of photoactivated rhodopsin. This process is initiated by phosphorylation of its carboxyl terminus by G protein-coupled receptor kinase 1 (GRK1). Previously, we showed that GRK1 is phosphorylated in the dark at Ser21 in a cAMP-dependent manner and dephosphorylated in the light. Results in vitro indicate that dephosphorylation of Ser21 increases GRK1 activity, leading to increased phosphorylation of rhodopsin. This creates the possibility of light-dependent regulation of GRK1 activity and its efficiency in inactivating the visual pigment. To address the functional role of GRK1 phosphorylation in rods and cones in vivo, we generated mutant mice in which Ser21 is substituted with alanine (GRK1-S21A), preventing dark-dependent phosphorylation of GRK1. GRK1-S21A mice had normal retinal morphology, without evidence of degeneration. The function of dark-adapted GRK1-S21A rods and cones was also unaffected, as demonstrated by the normal amplitude and kinetics of their responses obtained by ex vivo and in vivo ERG recordings. In contrast, rod dark adaptation following exposure to bright bleaching light was significantly delayed in GRK1-S21A mice, suggesting that the higher activity of this kinase results in enhanced rhodopsin phosphorylation and therefore delays its regeneration. In contrast, dark adaptation of cones was unaffected by the S21A mutation. Taken together, these data suggest that rhodopsin phosphorylation/dephosphorylation modulates the recovery of rhodopsin to the ground state and rod dark adaptation. They also reveal a novel role for cAMP-dependent phosphorylation of GRK1 in regulating the dark adaptation of rod but not cone photoreceptors.
关键词： vision,phototransduction,photoreceptor,protein phosphorylation,cAMP
更新于2025-09-16 10:30:52
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Protein profiling analysis based on matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry and its application in typing Streptomyces isolates
摘要： Marine Streptomyces is a potential source of novel bioactive natural products in medicine and agriculture. The current discrimination and screening method of Streptomyces isolates is not accurate and time-consuming, and a novel method is necessary. In this study, a protein profiling method based on an ultrahigh resolution 15 Tesla Matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) was established and applied for differentiation and bioactivity screening of marine Streptomyces isolates. To obtain robust protein profiling, the effects of the protein extraction method, the matrix-solvent, the sample deposition mode, and the culture time of isolates on protein profiling were thoroughly studied, the optimal conditions were obtained. To evaluate the performance of the developed MALDI-FTICR MS method, MALDI-time of flight (TOF) MS and 16S rRNA were applied in parallel to analyze 25 marine Streptomyces isolates. We found that the clustering result of MALDI-FTICR MS was more similar to that of 16S rRNA than MALDI-TOF MS. And MALDI-FTICR MS could effectively indicate the antibacterial activity of Streptomyces isolates against three plant pathogenic bacteria including Xanthomonas campestris, Xanthomonas oryzae and Erwinia carotovora. Furthermore, a differential protein/peptide was defined and successfully applied to predict antibacterial activity of blind samples. This study demonstrated that MALDI-FTICR MS has great potential to discriminate and screen complex microorganisms, especially those closely related strains.
关键词： Protein profiling,Streptomyces isolates,Cluster analysis,Activity screening,Matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
更新于2025-09-16 10:30:52
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Application of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric Imaging in Analysis of Medicinal Plants
摘要： Whey proteins (WPs) modification can improve their functional properties. To assess the crosslinking characteristics of Bacillus subtilis transglutaminase (BTG), it was used to reacted with WPs (12%, w/v) (40 °C, pH 8.0) for 6 h and 12 h, respectively. Both particle size profile and sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that BTG treatment enhanced the molecular weight of WPs. Meanwhile, BTG crosslinking greatly increased (*P < 0.05) the foaming and emulsifying properties of WPs. Furthermore, the rheological evaluation indicated that the cross-linked WPs showed greater storage modulus and loss modulus in comparison to the native WPs, leading to the increased gel strength. Additionally, BTG-induced WPs gels exhibited significantly enhanced (*P < 0.05) textural properties and water holding capacity. These results suggested the potential of BTG to enhance the functional properties of many proteins in the food industry.
关键词： Functional property,Bacillus subtilis transglutaminase,Whey protein,Cross-linking
更新于2025-09-16 10:30:52
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Activated Plasmonic Nanoaggregates for Dark-Field in Situ Imaging for HER2 Protein Imaging on Cell Surfaces
摘要： Dark-?eld microscopy (DFM) based on localized surface plasmon resonance (LSPR) was used for observation of experimental phenomena, which is a hopeful nondamaging and non-photobleaching biological imaging technique. In this strategy, plasma nanoaggregates with stronger scattering e?ciency were formed in the presence of the target, causing a “turn-on” phenomenon, when asymmetry modi?ed AuNPs were introduced as probes with zero LSPR background. First, ?CC probe were designed for the cycloaddition between azide and alkyne Au1 to form AuNP dimers under catalytic action by Cu+, which was obtained from the reduction of Cu2+ by sodium ascorbate. The two kinds of probes were successfully used for the detection of Cu2+ in rat serum. Then, to apply this concept to protein on cells, DNA and antibody were modi?ed on the ?CC probe were proposed for HER2 protein DFM on cells. By designing an aptamer sequence in primer, the rolling circle ampli?cation (RCA) was introduced in HER2 DFM on cells, and the image signal was much brighter than that from no-RCA. The unique design made it easier to discriminate the target signal from background noise in cell DFM. This method might be used in the ?elds of molecular diagnostics and cell imaging.
关键词： click chemistry,rolling circle ampli?cation,localized surface plasmon resonance,AuNPs,HER2 protein,Dark-?eld microscopy
更新于2025-09-16 10:30:52
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Liquid crystal-based capacitive, electro-optical and dielectric biosensors for protein quantitation
摘要： The electrical, electro-optical and dielectric properties of liquid crystals (LCs) are routinely manipulated in liquid-crystal display (LCD) devices, but their potential application in the development of biosensors is still in a nascent stage. In this review, utilising the electrical properties, electro-optical effect and dielectric anisotropy in LCs, we provide insights into several possible modes of label-free biodetection and describe how capacitance, electro-optical and dielectric measurements of various LCs assist in quantitative analysis of biomolecules. It is concluded that the electrically induced biosensing techniques proposed here provides new incentives for researchers to study the interaction between LCs and biomolecules and to resolve technical hurdles facing the development of LC-based biosensors.
关键词： bovine serum albumin,biosensing,dielectric spectroscopy,Electro-optical measurement,protein,capacitance
更新于2025-09-16 10:30:52
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Gr/TiO2 films with light controlled positive/negative charge for cell harvesting application
摘要： Light-induced cell harvest shows much potential in in vitro cell culture. In this work, a light-responsive monolayer graphene (Gr)/titanium dioxide nanodots (TN) film is designed and used for light induced cell harvest. It is found that after 20 min of 365 nm UV or 450 nm visible light illumination, different types of cells could be detached from the surface effectively. The highest cells detachment ratio reaches about 95%. The mechanism of such cell detachment is contributed to that light illumination generates charges accumulation, which, in turn, changes the conformation of extracellular matrix protein molecules adsorbed to a more disordered state, and eventually leads to the cells detachment. Such UV and visible light responsive Gr/TiO2 film could be a good candidate for surface with light-induced cell detachment property.
关键词： protein conformation,cell harvest,light illumination,surface charges,graphene/TiO2 nanodots
更新于2025-09-16 10:30:52
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Simultaneous determination of proteins in microstructured optical fibers supported by chemometric tools
摘要： A new perspective on the relevant problem—creating simple, rapid, and efficient protein sensors based on microstructured optical fibers using a simple homogeneous analysis format—was proposed. Commercially available long-period grating hollow core microstructured optical fibers (LPG HCMOF) were used to determine bovine serum albumin (BSA) and albumin from chicken eggs (OVA) in binary mixtures as well as immunoglobulin G (IgG) in the presence of BSA and OVA. LPG HCMOF transmission spectra allowed the detection of both BSA and OVA up to 10 mg/mL with LOD as low as 0.1 and 0.8 μg/mL, respectively. Partial least squares regression (PLS) was utilized for modeling of LPG HCMOF spectral data and quantitative analysis of BSA, OVA, total protein, and IgG in binary and ternary mixtures. Rather high coefficients of determination (R2) and low root mean square error for the calibration (RMSEC) (15%) and prediction (RMSEP) (20%) were obtained for all PLS models. The proposed approach was tested in the analysis of BSA in spiked horse blood hemolyzed (HBH). The results demonstrated the functionality of the proposed approach and offered the opportunity for the creation of a wide range of sensors for protein determination in complex mixtures.
关键词： Chemometrics,Partial least squares regression,Protein determination,Long-period grating fiber,Microstructured optical fibers
更新于2025-09-16 10:30:52
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Controlled assembly of AIEgens based on a super-quadruplex scaffold for detection of plasma membrane proteins
摘要： Quantification of plasma membrane proteins (PMPs) is crucial for understanding the fundamentals of cellular signaling systems and their related diseases. In this work, a super-quadruplex scaffold was designed to regulate assembly of oligonucleotide-grafted AIEgens for detection of PMPs. The nonfluorescence oligonucleotide-grafted AIEgen (Oligo-AIEgen) was firstly synthesized by attaching the AIEgen to 3′-terminus of the oligonucleotide through click chemistry. Meanwhile, the tetramolecular hairpin-conjugated super-quadruplex (THP-G4) as cleavage element and signal enhancement scaffold composited of three elements: a substrate sequence of DNAzyme in the loop region, partial hybridization region in the stem, and six guanine nucleotides to form G-quadruplex. Once the DNAzyme was anchored on the specific PMPs through aptamer-protein recognition, the substrate sequence on the loop of THP-G4 was cleaved by DNAzyme with the aid of cofactor MnII, resulting in the conformation switch of THP-G4 to the activated G-quadruplex scaffold. The latter could assemble Oligo-AIEgens to generate aggregation-induced emission (AIE) enhancement, resulting in a simple and sensitive strategy for detection of membrane proteins. Moreover, the DNAzyme continuously cut the next THP-G4 to achieve recycling amplification. Under the optimized conditions, this AIE-based strategy exhibited good linear relationship with the logarithm of MUC1 concentration from 0.01 to 10 μg mL-1 with the limit of detection down to 4.3 ng mL-1. The G4-assembled AIEgens provides a universal platform for detecting various biomolecules and a proof-of concept for AIE biosensing.
关键词： Biosensors,Fluorescence,DNAzyme,Aggregation-induced emission,DNA quadruplexes,Plasma membrane protein
更新于2025-09-16 10:30:52