An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd2+ and Pb2+. The results showed that the ...electrodes can quantitatively detect trace Cd2+ and Pb2+, and with satisfied limit of detection, which has great significance in electrochemical analysis and detection.
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An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd2+ and Pb2+. The experimental results showed that the electrochemical performance of nanoPPCPE is evidently better than both glassy carbon electrode (GCE) and pure carbon paste electrode (CPE). Then the prepared nano-PPCPE was applied to detect Cd2+ and Pb2+ in standard solution, the results showed that the electrodes can quantitatively detect trace Cd2+ and Pb2+, which has great significance in electrochemical analysis and detection. The linear ranges between the target ions concentration and the DPASV current were from 0.1–3.0 μmol/L, 0.05–4.0 μmol/L for Cd2+ and Pb2+, respectively. And the detection limits were 0.0780 μmol/L and 0.0292 μmol/L, respectively. Moreover, the preparation of the nano-PPCPE is cheap, simple and has important practical value.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A simple visual method for DNA detection during the formation of gold nanoparticles (AuNPs) was developed based on different electrostatic properties of single strand DNA (ssDNA) and double strand ...DNA (dsDNA). It could identify target DNA in 10 min.
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A simple visual method for DNA detection during the formation of gold nanoparticles (AuNPs) was developed based on different electrostatic properties of single strand DNA (ssDNA) and double strand DNA (dsDNA). Since the ssDNA is easy to bind to AuNPs due to its exposed bases which could prevent salt-induced aggregation of AuNPs. The dsDNA always present negative charge because its negatively charged phosphate backbone is exposed. In this case, the dsDNA could disturb the adsorption between dsDNA and AuNPs and result in non-aggregation of AuNPs. After hybridization, chloroauric acid and ascorbic acid were added to the mixture solution, and the solution changed to red immediately and turned to purple in 10 min in the present of target DNA. TEM results confirmed that the change of color stemed from aggregation of AuNPs. In order to obtain accurate results by naked eye, the DNA detection assay should be conducted under pH 7.0.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study aims to restore grating lobe artifacts and improve the image resolution of sparse array ultrasonography via a deep learning predictive model. A deep learning assisted sparse array was ...developed using only 64 or 16 channels out of the 128 channels in which the pitch is two or eight times the original array. The deep learning assisted sparse array imaging system was demonstrated on ex vivo porcine teeth. 64- and 16-channel sparse array images were used as the input and corresponding 128-channel dense array images were used as the ground truth. The structural similarity index measure, mean squared error, and peak signal-to-noise ratio of predicted images improved significantly (p < 0.0001). The resolution of predicted images presented close values to ground truth images (0.18 mm and 0.15 mm versus 0.15 mm). The gingival thickness measurement showed a high level of agreement between the predicted sparse array images and the ground truth images, as indicated with a bias of -0.01 mm and 0.02 mm for the 64- and 16-channel predicted images, respectively, and a Pearson's r = 0.99 (p < 0.0001) for both. The gingival thickness bias measured by deep learning assisted sparse array imaging and clinical probing needle was found to be <0.05 mm. Additionally, the deep learning model showed capability of generalization. To conclude, the deep learning assisted sparse array can reconstruct high-resolution ultrasound image using only 16 channels of 128 channels. The deep learning model performed generalization capability for the 64-channel array, while the 16-channel array generalization would require further optimization.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A tumor microenvironment is distinct from normal tissue cells in characteristic physiochemical conditions, based on which we can design tumor-specific therapy modalities. Herein, we introduce a ...concept of multimodal therapies, which integrates the characteristics of each therapy modality for efficient tumor therapy: tumor starvation-triggered synergism with enhanced chemodynamic therapy and activated chemotherapy. Fe
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nanoparticles (Fenton reaction catalysts) and a hypoxic prodrug tirapazamine (TPZ) were loaded in mesoporous silica nanoparticles (MSN) and GOX was grafted onto its surface, which was designed and fabricated for sequential multimodal therapies. Logically, glucose oxidase (GOX) deprived tumor cells of nutrients (glucose and oxygen) for starvation therapy and tumorous abnormality amplifications (elevated acidity, exacerbated hypoxia, and increased H
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) were amplified by the GOX-driven oxidation reaction simultaneously. Specifically, elevated acidity could accelerate the release of iron ions and enhanced Fenton reaction efficiency. Associated with increased H
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, an elevated ROS level was detected, which enhanced the chemodynamic therapy. Exacerbated hypoxia activated the hypoxic prodrug TPZ for tumor-specific chemotherapy programmatically. Particularly,
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integrating starvation therapy, enhanced chemodynamic therapy, and activated chemotherapy, the sequential multimodal therapies were specifically designed for the tumor microenvironment and achieved effective abnormality amplifications and high therapeutic efficacy.
A tumor microenvironment is distinct from normal tissue cells in characteristic physiochemical conditions, based on which we can design tumor-specific therapy modalities.
We report here a colorimetric method for rapid detection of norovirus based on the valence-driven peptide-AuNP interactions. We engineered a peptide sequence named K1 with a cleavage sequence in ...between two lysine residues. The positively charged lysine groups aggregated the negatively charged nanoparticles leading to a purple color change. There was a red color when the cleavage sequence was digested by the Southampton norovirus 3C-like protease (SV3CP)-a protease involved in the life cycle of Human norovirus (HNV). The limit of detection was determined to be 320 nM in Tris buffer. We further show that the sensor has good performance in exhaled breath condensate, urine, and faecal matter. This research provides a potential easy and quick way to selectively detect HNV.
A SV3CP-responsive peptide has various performance towards the aggregation of AuNPs with different charge valence.
Aromatic interactions are commonly involved in the assembly of naturally occurring building blocks, and these interactions can be replicated in an artificial setting to produce functional materials. ...Here we describe a colorimetric biosensor using co‐assembly experiments with plasmonic gold and surfactant‐like peptides (SLPs) spanning a wide range of aromatic residues, polar stretches, and interfacial affinities. The SLPs programmed in DDD−(ZZ)x−FFPC self‐assemble into higher‐order structures in response to a protease and subsequently modulate the colloidal dispersity of gold leading to a colorimetric readout. Results show the strong aggregation propensity of the FFPC tail without polar DDD head. The SLPs were specific to the target protease, i.e., Mpro, a biomarker for SARS‐CoV‐2. This system is a simple and visual tool that senses Mpro in phosphate buffer, exhaled breath condensate, and saliva with detection limits of 15.7, 20.8, and 26.1 nM, respectively. These results may have value in designing other protease testing methods.
A colorimetric probe for the SARS‐CoV‐2 protease is reported by modulating the interplay of peptide amphiphiles and gold nanoparticles via aromatic interactions. This probe showed good performance in exhaled breath and saliva, demonstrating a favorable strategy for designing amphiphilic peptides for plasmonic coupling in complex media.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Plasmonic coupling via nanoparticle assembly is a popular signal-generation method in bioanalytical sensors. Here, we customized an all-peptide-based ligand that carries an anchoring group, ...polyproline spacer, biomolecular recognition, and zwitterionic domains for functionalizing gold nanoparticles (AuNPs) as a colorimetric enzyme sensor. Our results underscore the importance of the polyproline module, which enables the SARS-CoV-2 main protease (Mpro) to recognize the peptidic ligand on nanosurfaces for subsequent plasmonic coupling via Coulombic interactions. AuNP aggregation is favored by the lowered surface potential due to enzymatic unveiling of the zwitterionic module. Therefore, this system provides a naked-eye measure for Mpro. No proteolysis occurs on AuNPs modified with a control ligand lacking a spacer domain. Overall, this all-peptide-based ligand does not require complex molecular conjugations and hence offers a simple and promising route for plasmonic sensing other proteases.
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IJS, KILJ, NUK, PNG, UL, UM
Triggering lysosome-regulated immunogenic cell death (ICD, e.g., pyroptosis and necroptosis) with nanomedicines is an emerging approach for turning an "immune-cold" tumor "hot"-a key challenge faced ...by cancer immunotherapies. Proton sponge such as high-molecular-weight branched polyethylenimine (PEI) is excellent at rupturing lysosomes, but its therapeutic application is hindered by uncontrollable toxicity due to fixed charge density and poor understanding of resulted cell death mechanism. Here, a series of proton sponge nano-assemblies (PSNAs) with self-assembly controllable surface charge density and cell cytotoxicity are created. Such PSNAs are constructed via low-molecular-weight branched PEI covalently bound to self-assembling peptides carrying tetraphenylethene pyridinium (PyTPE, an aggregation-induced emission-based luminogen). Assembly of PEI assisted by the self-assembling peptide-PyTPE leads to enhanced surface positive charges and cell cytotoxicity of PSNA. The self-assembly tendency of PSNAs is further optimized by tuning hydrophilic and hydrophobic components within the peptide, thus resulting in the PSNA with the highest fluorescence, positive surface charge density, cell uptake, and cancer cell cytotoxicity. Systematic cell death mechanistic studies reveal that the lysosome rupturing-regulated pyroptosis and necroptosis are at least two causes of cell death. Tumor cells undergoing PSNA-triggered ICD activate immune cells, suggesting the great potential of PSNAs to trigger anticancer immunity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We report here a colorimetric method for rapid detection of norovirus based on the valence-driven peptide-AuNP interactions. We engineered a peptide sequence named K1 with a cleavage sequence in ...between two lysine residues. The positively charged lysine groups aggregated the negatively charged nanoparticles leading to a purple color change. There was a red color when the cleavage sequence was digested by the Southampton norovirus 3C-like protease (SV3CP)—a protease involved in the life cycle of Human norovirus (HNV). The limit of detection was determined to be 320 nM in Tris buffer. We further show that the sensor has good performance in exhaled breath condensate, urine, and faecal matter. This research provides a potential easy and quick way to selectively detect HNV.
Better insights into the fate of membraneless organelles could strengthen the understanding of the transition from prebiotic components to multicellular organisms. Compartmentalized enzyme reactions ...in a synthetic coacervate have been investigated, yet there remains a gap in understanding the enzyme interactions with coacervate as a substrate hub. Here, we study how the molecularly crowded nature of the coacervate affects the interactions of the embedded substrate with a protease. We design oligopeptide-based coacervates that comprise an anionic Asp-peptide (D10) and a cationic Arg-peptide (R5R5) with a proteolytic cleavage site. The coacervates dissolve in the presence of the main protease (Mpro) implicated in the coronavirus lifecycle. We capitalize on the condensed structure, introduce a self-quenching mechanism, and model the enzyme kinetics by using Cy5.5-labeled peptides. The determined specificity constant (k cat/KM) is 5817 M–1 s–1 and is similar to that of the free substrate. We further show that the enzyme kinetics depend on the type and quantity of dye incorporated into the coacervates. Our work presents a simple design for enzyme-responsive coacervates and provides insights into the interactions between the enzyme and coacervates as a whole.
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IJS, KILJ, NUK, PNG, UL, UM
