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Surface-Enhanced Raman Scattering (SERS) With Silver Nano Substrates Synthesized by Microwave for Rapid Detection of Foodborne Pathogens
摘要： Rapid and sensitive methods have been developed to detect foodborne pathogens, a development that is important for food safety. The aim of this study is to explore Surface-enhanced Raman scattering (SERS) with silver nano substrates to detect and identify the following three foodborne pathogens: Escherichia coli O157: H7, Staphylococcus aureus and Salmonella. All the cells were resuspended with 10 mL silver colloidal nanoparticles, making a concentration of 107 CFU/mL, and were then exposed to 785 nm laser excitation. In this study, the results showed that all the bacteria can be sensitively and reproducibly detected directly by SERS. The distinctive differences can be observed in the SERS spectral data of the three food-borne pathogens, and the silver colloidal nanoparticles can be used as highly sensitive SERS-active substrates. In addition, the assay time required only a few minutes, which indicated that SERS coupled with the silver colloidal nanoparticles is a promising method for the detection and characterization of food-borne pathogens. At the same time, principle component analysis (PCA) and hierarchical cluster analysis (HCA) made the different bacterial strains clearly differentiated based on the barcode spectral data reduction. Therefore, the SERS methods hold great promise for the detection and identification of food-borne pathogens and even for applications in food safety.
关键词： silver nanoparticles,rapid detection,food safety,Surface-enhanced Raman scattering,foodborne pathogens,bioanalysis
更新于2025-09-23 15:22:29
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Cuvette-based microfluidic device integrated with nanostructures for measuring dual Localized Surface Plasmon Resonance (LSPR) signals
摘要： A spectrophotometer that uses a localized surface plasmon resonance phenomenon is a powerful measurement tool in the biotechnology and bioanalysis fields. We propose a novel cuvette design type that can be used for universal spectrophotometers. The novel cuvette design needs a few μl reagent for measuring, and also two chips for measurement can be loaded and measured at the same time. A new cuvette can easily be used several times because of sample chips to be loaded and unloaded since they are mechanically mounted by screws. Therefore, it can offer advantages to users in terms of cost and time. We verify its possibility for use in the biotechnology and bioanalysis fields by a signal enhancement and dual signal detection.
关键词： spectrophotometer,bioanalysis,nanostructures,microfluidic device,biotechnology,Localized Surface Plasmon Resonance,LSPR
更新于2025-09-23 15:21:01
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Enzyme modulation of quantum dot luminescence: Application in bioanalysis
摘要： The new bioanalysis systems development is an important step to the quality of people life improving. A significant number of novel bioanalytical methods bases on quantum dots photoluminescent signal detection and determination. A separate class of that kind of analytical system is enzyme-based luminescent assays, in which the value of quantum dots photoluminescence change by the product of the enzymatic reaction is used for the analyte concentration determination. The advantageous attributes of the photoluminescence quenching based systems are the simple equipment requirements, inexpensiveness, availability to use by the non-professionals and using an only dilution of the samples before analysis without any other pretreatment. Described bioanalytical systems are applicable in health care, food analysis and agriculture for a large number of objects. The key aim of the review is to compile the shortcomings and disadvantages of the published detection systems preventing their commercial application and searching the possible solutions.
关键词： Bioanalysis,Immunoassay,Sensor development,Quantum dots,Luminescence,Enzyme catalisys
更新于2025-09-23 15:19:57
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Dextran-Functionalized Semiconductor Quantum Dot Bioconjugates for Bioanalysis and Imaging
摘要： The prerequisites for maximizing the advantageous optical properties of colloidal semiconductor quantum dots (QDs) in biological applications are effective surface functionalization and bioconjugation strategies. Functionalization with dextran has been highly successful with some nanoparticle materials, but has had very limited application with QDs. Here, we report the preparation, characterization, and proof-of-concept applications of dextran-functionalized QDs. Multiple approaches to dextran ligands were evaluated, including performance with respect to colloidal stability across a range of pH, nonspecific binding with proteins and cells, and microinjection into cells and viability assays. Multiple bioconjugation strategies were demonstrated and applied, including covalent coupling to develop a simple pH sensor, binding of polyhistidine-tagged peptides to the QD for energy transfer-based proteolytic activity assays, and binding with tetrameric antibody complexes (TACs) to enable a sandwich immunoassay and cell immunolabeling and imaging. Our results show that dextran ligands are highly promising for the functionalization of QDs, and that the design of the ligands is tailorable to help optimally meet the requirements of applications.
关键词： dextran,quantum dots,colloidal stability,imaging,bioconjugation,bioanalysis
更新于2025-09-23 15:19:57
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Ultrasensitive Paper-Based Photoelectrochemical Sensing Platform Enabled by the Polar Charge Carriers-Created Electric Field
摘要： Efficient separation of electron-hole pairs is vitally crucial to enhancing the analytical performance of paper-based photoelectrochemical (PEC) bioanalysis. Herein, a simple but effective strategy is developed to modulate the effective separation of photogenerated electrons and holes via introducing a polar charge carriers-created (PCC) electric field induced by a classical perovskite ferroelectric BaTiO3 (BTO). By inserting it between the n-type WO3 nanoflakes and p-type Cu2O (WO3 nanoflakes/BTO/Cu2O), the photoelectrode is endowed with a renewable PCC electric field, as a sustaining driving force, to guarantee the realization of directional separation of charge carrier (DSCC) strategy in PEC bioanalysis. The enduring PCC electric field can attract the electrons of Cu2O and holes of WO3, respectively, thereby regulating the directional migration of charge carriers and achieving an enhanced PEC photocurrent for the ultrasensitive quantification based on the highly efficient separation of electron-hole pairs. Consequently, with respect to WO3 nanoflakes/Cu2O and WO3 nanoflakes photoelectrode, the polarized WO3 nanoflakes/BTO/Cu2O photoelectrode exhibits 1.7 and 10.9 times higher photocurrent density, respectively. Benefiting from this, the prominent photocurrent density is obtained which is extremely beneficial for enhancing the sensitivity of PEC bioanalysis. Ultimately, the ultrasensitive detection of model prostate specific antigen (PSA) is realized and presented a linear range of 0.1 pg/mL-50 ng/mL with the detection limitation of 0.036 pg/mL. This work provides the basis for understanding the role of the polarized electric field induced by ferroelectric in tuning the charge separation as well as insights on strategies for constructing high-performance paper-based PEC bioanalysis.
关键词： WO3,BaTiO3,PSA,photoelectrochemical,Cu2O,ferroelectric,bioanalysis
更新于2025-09-19 17:13:59
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Self-Assembled Peptide Nanostructures for Photoelectrochemical Bioanalysis Application: A Proof-of-Concept Study
摘要： Currently, one of important research directions of photo-electrochemical (PEC) bioanalysis is to exploit innovative photoactive species and their elegant implementations for selective detection and signal transduction. Different from existing candidates for photoelectrode development, this study, exemplified by the cationic dipeptide nanoparticles (CDNPs), reports the first demonstration of self-assembled peptide nanostructures (SAPNs) for the PEC bioanalysis. Specifically, the CDNPs were prepared as representative materials and then immobilized onto the indium tin oxide (ITO) electrode for the PEC differentiation of several commonly involved biomolecules such as ascorbic acid (AA) and L-cysteine. Significantly, the experimental results disclosed that the CDNPs possessed unique photocathodic responses and good analytical performance toward AA detection in terms of rapid response, high stability, and excellent selectivity. This work demonstrates the great potential of the large SAPN family for the future PEC bioanalysis development and has not been reported to our knowledge.
关键词： ascorbic acid detection,photoelectrochemical bioanalysis,cationic dipeptide nanoparticles,self-assembled peptide nanostructures
更新于2025-09-16 10:30:52
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Immobilization of ssDNA on the surface of silver nanoparticles-graphene quantum dots modified by gold nanoparticles towards biosensing of microorganism
摘要： Rapid screening of pathogenic microorganisms are widely demand in the last decade. According to fastidious and hard to grow nature, Legionella penumophila is important pathogen for bioassay and biomedical analysis. In this work a novel paper-based genoassay was developed for monitoring of L. penumophila. For the first time, silver-graphene quantum dots (Ag/GQDs) ink was synthesized and used for construction of new substrate for bioassay of L. penumophila. The prepared interface was modified by gold nanoparticles grafted by Cysteamine A (CysA/AuNPs) which is necessary for ssDNA immobilization and hybridization by cDNA. All of the genoassay fabrication steps were characterized by field emission scanning electron microscope (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), Atomic force microscopic (AFM) and also TEM (transmission electron microscopy). Using chronoamperometry technique, the measurement of target cDNA was performed successfully. Also, cDNA was determined in the linear rang of 1μM to 1ZM which low limit of quantification was 1ZM. The results show that the designed bio-platform despite a simple structure with high sensitivity and specificity for the DNA based bioassay of L. penumophila genome.
关键词： nanotechnology,hybridization,biosensor,nucleic acid,advanced nanomaterial,bioanalysis
更新于2025-09-11 14:15:04
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Common Aspects Influencing the Translocation of SERS to Biomedicine
摘要： This review overviews the impact in biomedicine of surface enhanced Raman scattering motivated by the great potential we believe this technique has. We present the advantages and limitations of this technique relevant to bioanalysis in vitro and in vivo and how this technique goes beyond the state of the art of traditional analytical, labelling and healthcare diagnostic technologies.
关键词： early diagnosis,Biomedicine,nanoparticles,hybrid plasmonic platforms,bioanalytes,Surface-enhanced Raman Scattering (SERS),multiplexed bioanalysis,biosensors
更新于2025-09-10 09:29:36
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Paper-based miniaturized immunosensor for naked eye ALP detection based on digital image colorimetry integrated with smartphone
摘要： Alkaline phosphatase (ALP) is a metalloprotein found naturally in raw milk samples and is considered as an important biomarker in quality control of milk. Its easy, personalized, as well as instrument-less detection is important to ensure the pasteurization and its differentiation form raw milk. In view of such importance of APL, we have developed an office punching machine crafted paper biosensor for naked eye detection of ALP in milk samples. The quantitative estimation is done by digital image colorimetry (DIC) based technique integrated with smartphone. The sensor-probe was developed by the covalent immobilization of ALP antibody (anti-ALP) onto the functionalized paper surface. The fabrication of the biosensing probe was characterized using DIC, Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). The detection was based on immunocomplexation between the sensor-probe and ALP, which generates blue-green precipitate as an analytical signal by exploiting the catalytic activity of ALP towards 5-bromo-4-chloro 3-indolyl phosphate (BCIP). The dose dependent appearance of the blue-green complex was captured using smartphone camera and DIC was employed using Red, Green, and Blue (RGB) profiling system, where the maximum sensitivity was obtained for the red color channel. Based on the DIC analysis, a wide dynamic range for the ALP detection is obtained from 10-1000 U/mL with the detection limit of 0.87 (±0.07) U/mL. The designed paper-based biosensor is successfully applied to detect ALP in commercial and raw milk samples. Interferences due to components present in the milk samples was evaluated and the long-term stability of the designed biosensor was examined. Based on the detection principle, a miniaturized kit [20.0 mm (L) x 20.0 mm (W) x 2.15 mm (H)] was developed and applied for the ALP detection to demonstrate the instrument-free direct in-kitchen applicability.
关键词： Miniaturized prototype,Alkaline phosphatase,Paper biosensor,Digital image colorimetry,Bioanalysis
更新于2025-09-04 15:30:14