Detection Of Foodborne Pathogens Research Articles

Flexible Biosensors for Food Pathogen Detection

AbstractFood contamination poses a significant threat to public health, the economy, and human health worldwide, occurring at any stage of the food supply chain, from farm to fork. Efficient and effective real‐time monitoring methods for the early identification and rapid detection of pathogen contamination are critical to preventing possible food safety issues. In the past decade, flexible electrochemical biosensors have rapidly expanded in the detection of foodborne pathogens, owing to their ability to function well at biological interfaces that may be soft, intrinsically curvy, irregular, or deformable. The most important features of flexible sensors are their flexibility, multifunctionality, low cost, and good compatibility with solution processing methods. These properties enable flexible sensors to be used in various applications, including smart packaging. This review focuses on the materials, structures, and fabrication methods of flexible biosensors, as well as their applications in food safety monitoring. It examines recent advances in electrochemical immunosensors and aptasensors for pathogen detection, with a focus on their key components and their application in food analysis, while critically examining their current trends, particularly in conjunction with nanomaterials such as carbon nanotubes, graphene, gold nanoparticles, Indium tin oxide, etc. Finally, current issues and prospects for the future are discussed.

Research progress on the detection of foodborne pathogens based on aptamer recognition.

Foodborne diseases caused by bacterial contamination are a serious threat to food safety and human health. The classical plate culture method has the problems of long detection cycle, low sensitivity and specificity, and complicated operation, which cannot meet the growing demand for rapid quantitative detection of pathogenic bacteria. The frequent outbreak of foodborne diseases has put forward higher requirements for rapid and simple detection technology of foodborne pathogens. Aptamer is a kind of oligonucleotide fragment that can recognize targets with the advantages of high affinity and good specificity. The target can be range from proteins, small molecules, cells bacteria, and even viruses. Herein, the latest advances in sensitive and rapid detection of foodborne pathogens based on aptamer recognition was reviewed. Special attention has been paid to the obtained sequences of aptamers to various foodborne pathogens, the optimization of sequences, and the mechanism of aptamer recognition. Then, the research progress of biosensors for the detection of pathogenic bacteria based on aptamer recognition were summarized. Some challenges and prospects for the detection of foodborne pathogens based on aptamer recognition were prospected. In summary, with the further deepening of aptamer research and improvement of detection technology, aptamer-based recognition can meet the needs of rapid, sensitive, and accurate detection in practical applications.

Comparing two magnetic separation pretreatment methods for molecular detection using (q)PCR assays targeting Staphylococcus aureus in milk as models

Magnetic separation presents significant potential for culture-independent detection of foodborne pathogens in food samples. In this study, we compared two magnetic separation pretreatment strategies for molecular detection using (q)PCR assays targeting Staphylococcus aureus in milk as models. The first approach employed amino-modified silica magnetic particles (ASMPs) for DNA separation, while the second utilized pig IgG-labeled magnetic beads (IgG-MBs) for cell separation. In the ASMPs-based DNA separation strategy, a sensitivity of 36 CFU/mL was achieved when ASMPs-DNA complexes were employed as templates for PCR analysis. To mitigate noise signals originating from ASMPs during qPCR, DNA on the surface of ASMPs was replaced with dNTP, resulting in a sensitivity of 1.6 × 103 CFU/mL. The IgG-MBs-based cell separation approach yielded sensitivities of 3.6 × 104 CFU/mL for PCR and 1.6 × 103 CFU/mL for qPCR following DNA isolation from the bacteria-IgG-MBs complexes. Both methods exhibited exceptional specificity and robustness against background bacteria interference. However, neither approach effectively discriminated between live and dead bacteria. In comparison, the ASMPs-based DNA separation strategy exhibited superior potential especially when ASMPs do not influence the detection system. This research contributes to the optimization of magnetic separation pretreatment strategies for the molecular detection of foodborne pathogens, highlighting the potential of culture-independent detection methods.

WO3 Nanoplates Decorated with Au and SnO2 Nanoparticles for Real-Time Detection of Foodborne Pathogens.

Nowadays, metal oxide semiconductor gas sensors have diverse applications ranging from human health to smart agriculture with the development of Internet of Things (IoT) technologies. However, high operating temperatures and an unsatisfactory detection capability (high sensitivity, fast response/recovery speed, etc.) hinder their integration into the IoT. Herein, a ternary heterostructure was prepared by decorating WO3 nanoplates with Au and SnO2 nanoparticles through a facial photochemical deposition method. This was employed as a sensing material for 3-hydroxy-2-butanone (3H-2B), a biomarker of Listeria monocytogenes. These Au/SnO2-WO3 nanoplate-based sensors exhibited an excellent response (Ra/Rg = 662) to 25 ppm 3H-2B, which was 24 times higher than that of pure WO3 nanoplates at 140 °C. Moreover, the 3H-2B sensor showed an ultrafast response and recovery speed to 25 ppm 3H-2B as well as high selectivity. These excellent sensing performances could be attributed to the rich Au/SnO2-WO3 active interfaces and the excellent transport of carriers in nanoplates. Furthermore, a wireless portable gas sensor equipped with the Au/SnO2-WO3 nanoplates was assembled, which was tested using 3H-2B with known concentrations to study the possibilities of real-time gas monitoring in food quality and safety.

One-pot dual-CRISPR/Cas12b-mediated dUTP-LAMP for rapid and sensitive detection of foodborne pathogens without carryover contamination

Rapid and accurate detection of foodborne pathogens is of great significance for ensuring food safety. Currently, the CRISPR-Dx based on Cas12b, a new and better performing Cas enzyme, is very rare, and the vast majority require a two-step method, facing aerosol contamination. In this work, we reported a one-pot dual-CRISPR/Cas12b mediated dUTP-LAMP method for rapid and sensitive detection of foodborne pathogens without nucleic acid extraction and contamination-free. The design mechanism of sgRNAs in the one-pot CRISPR/Cas12b-mediated LAMP method was investigated in detail for the first time. Moreover, a novel PAM sequence UUN of AapCas12b was discovered, and combined with dUTP-LAMP system for one-pot dual-sgRNA detection without carryover contamination. Our developed method can achieve high specificity, nucleic acid extraction-free detection of 2.33 × 104 CFU/mL Salmonella within 1 h. Furthermore, accurate detection of Salmonella was successfully performed in real samples of milk, fruit and egg, demonstrating the practical significance of the developed method.

A CRISPR-Cas12a-powered, quantum dot-based and magnetic nanoparticle-assisted (QD-CRISPR-MNP) biosensor for the screening of Salmonella

Rapid detection methods are urgently needed to help prevent the spread of Salmonella among food products. Herein, a CRISPR-Cas12a-powered, quantum dot-based and magnetic nanoparticle-assisted (QD-CRISPR-MNP) biosensor was proposed for the screening of Salmonella. The QD-CRISPR-MNP biosensor was designed and fabricated relying on the CRISPR-Cas12a system for better guidance of the coupling between magnetic nanoparticles (MNPs) and quantum dots (QDs). In this biosensor, the activity of the CRISPR-Cas12a system was unlocked by Salmonella and displayed collateral cleavage activity towards linker DNAs, which inhibited the coupling of the MNPs and QDs. Then, Salmonella could be quantitatively detected by simply measuring the fluorescence emitted by the QDs on the MNPs surface. This biosensor showed good detection performance for Salmonella with a detection limit of 86 CFU mL−1, and exhibited a satisfactory specificity as well. Moreover, it overcomes the low fluorescence quantum yields and the possible high fluorescence background noise in conventional dye-based CRISPR detection platforms, acting as a powerful alternative for the detection of foodborne pathogens.

Photothermal-Based Multiplex Nested Digital PCR System for Rapid Detection of Foodborne Pathogens.

The rapid and sensitive detection of foodborne pathogens is crucial for ensuring food safety. Among virus testing methods, polymerase chain reaction (PCR) has served as the gold-standard technique in most food safety regulation organizations. However, to enhance the speed and efficiency of PCR, novel approaches are continually being explored. In this work, leveraging the photothermal effects and high thermal conductivity of gold nanoparticles, we have significantly improved the heating and cooling rates of thermal cycles, enabling ultra-fast PCR detection. Specifically, we present a pre-degassing multiplex digital PCR chip integrated with gold nanoparticles. We further developed a portable system with a light source for photothermal heating cycling, along with an optoelectronic sensor to analyze PCR amplification products after rapid thermal cycling. As proof of concept, the proposed chip and portable device was applied for the on-site detection of several types of foodborne pathogens, including Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Salmonella. The whole system could distinguish those pathogens within 20 min, showing good potential for the rapid detection of multiple types of foodborne pathogens.

Sensitive colorimetric aptasensor for multiple foodborne pathogens detection based on PCN-Mo peroxidase-like activity

A rapid and sensitive colorimetric biosensor was developed for simultaneous detection of various pathogenic bacteria based on aptamer-mediated peroxidase (POD)-like activity of PCN-Mo nanozyme. Initially, a porphyrin-based PCN-Mo metal organic framework (MOF) nanozyme is constructed through a simple hydrothermal method, as thoroughly figured out by a series of characterization techniques. The study showed that the pathogenic bacteria aptamers could adhere to the surface of PCN-Mo, and significantly enhanced the POD-like activity by reinforcing their transport of electrons to 3,3′,5,5′-tetramethylbenzidine (TMB). In the presence of different target bacteria, the aptamers tend to bind to bacteria specifically, causing the further enhancement of POD-like activity. Based on the signal-amplification by the PCN-Mo@aptamer (PCN-Mo@Apt) nanozyme, the constructed pathogenic bacteria sensor demonstrated a wide linear range between 101 to 105 CFU/mL, with the detection limits (LODs) of 0.578, 0.439, and 0.643 CFU/mL for E. coli, S. typhimurium and S. aureus, respectively. Furthermore, the PCN-Mo sensor was capable of detection pathogenic bacteria in water, milk, classic milk tea, chicken, and beef with the recoveries of 90.1%–104.1%, indicating the sensor's practicability for pathogenic bacteria detection in real samples.

Mesoporous Silica Nanoparticles-Enhanced Microarray Technology for Highly Sensitive Simultaneous Detection of Multiplex Foodborne Pathogens.

Ensuring food safety is paramount for the food industry and global health concerns. In this study, we have developed a method for the detection of prevalent foodborne pathogenic bacteria, including Escherichia coli, Salmonella spp., Listeria spp., Shigella spp., Campylobacter spp., Clostridium spp., and Vibrio spp., utilizing antibody-aptamer arrays. To enhance the fluorescence signals on the microarray, the mesoporous silica nanoparticles (MSNs) conjugated with fluorescein, streptavidin, and seven detection antibodies-biotin were employed, forming fluorescein doped mesoporous silica nanoparticles conjugated with detection antibodies (MSNs-Flu-SA-Abs) complexes. The array pattern was designed for easy readability and enabled the simultaneous detection of all seven foodborne pathogens, referred to as the 7FP-biochip. Following the optimization of MSNs-Flu-SA-Abs complexes attachment and enhancement of the detection signal in fluorescent immunoassays, a high level of sensitivity was achieved. The detection limits for the seven pathogens in both buffer and food samples were 102 CFU/mL through visual screening, with fluorescent intensity quantification achieving levels as low as 20-34 CFU/g were achieved on the antibody-aptamer arrays. Our antibody-aptamer array offers several advantages, including significantly reduced nonspecific binding with no cross-reaction between bacteria. Importantly, our platform detection exhibited no cross-reactivity among the tested bacteria in this study. The multiplex detection of foodborne pathogens in canned tuna samples with spiked bacteria was successfully demonstrated in real food measurements. In conclusion, our study presents a promising method for detecting multiple foodborne pathogens simultaneously. With its high sensitivity and specificity, the developed antibody-aptamer array holds great potential for enhancing food safety and public health.

Development of a 3D Microfluidic Analytical Device for the Detection of Pathogenic Bacteria in Commercial Food Samples with Loop-Mediated Isothermal Amplification

Traditional methods of detecting foodborne pathogens take several days to produce the required results. Furthermore, various molecular techniques (e.g., PCR) that also produce reliable results in the detection of pathogenic bacteria have been introduced, but the cost–time ratio required does not allow them to be considered a substantial solution to this specific problem. Three-dimensional (3D) printing technology provides the ability to design and manufacture microfluidic analytical devices using conventional 3D printers, which, in combination with colorimetric loop-mediated isothermal amplification (LAMP), may further simplify the process. The overall reduction in time and cost may provide the opportunity to upscale this diagnostic modality. Moreover, unlike most microfluidic analytical devices, this technique is simpler and more user-friendly, as it does not require any expertise or additional equipment apart from a conventional oven. A 3D-printed microfluidic analytical device in combination with LAMP was developed and tested for the simultaneous detection of foodborne pathogens in food samples. A total of 150 commercial food specimens (50 milk, 50 chicken, 50 lettuce samples) were analyzed for possible contamination with Salmonella typhimurium, Listeria monocytogenes and Escherichia coli. The 3D-printed microfluidic device was 100% precise for both negative (80 samples) and positive samples (7 samples were positive for S. typhimurium, 28 for L. monocytogenes, and 35 for E. coli) for all pathogens. Overall, the amount of data analyzed led to a high level of confidence in the precision of this device. As such, this new 3D device in combination with LAMP provides a precise detection method for food pathogens with a low detection limit.

Bacteriophage-assisted lysis and eluted genomic DNA-based detection of pathogenic bacterial contamination in food

Foodborne diseases represent a significant global health concern, with a substantial number of illnesses and fatalities reported annually owing to the consumption of contaminated food. Current methods for identifying foodborne pathogens cannot effectively distinguish live from dead bacteria or efficiently detect multiple targets. Therefore, we developed a selective detection method for three pathogenic bacteria in food samples that leverages bacteriophage-assisted live-cell lysis and exposed genomic DNA amplification. The antimicrobial activity and host specificity of these three bacteriophages were employed to confirm the target bacteria selectivity. Bacterial DNA purification using bacteriophage-assisted lysis demonstrated the superior activity of the selected phages in extracting DNA from Escherichia coli O157:H7 and Salmonella Typhimurium. The results from reactions involving the three strains, including Bacillus cereus, highlighted that a 1 h incubation period yielded the most efficient DNA extraction and purification. The polymerase chain reaction (PCR) products obtained were comparable in terms of concentration and purity with those generated using bacterial DNA prepared using a commercial kit. In the practical food sample application experiment, bacterial strains were successfully recovered and concentrated using a polyethersulfone filter, resulting in a concentration factor >3 for all samples. Furthermore, the concentration of purified bacterial DNA from contaminated kimchi cabbage exceeded 10 ng/μL. Notably, we could detect E. coli O157:H7, S. Typhimurium, and B. cereus spiked at 103 colony-forming units/mL using multiplex PCR. This innovative bacteriophage-based approach holds substantial promise for the selective and practical detection of live foodborne pathogens, thereby significantly advancing food safety standards.

Dynamically reconfigurable complex liquid crystal emulsions

ABSTRACT Complex emulsions, containing liquid crystals (LCs) and immiscible oils such as fluorocarbon or silicone oils, present innovative functionalities in soft materials. These emulsions exhibit dynamic reconfiguration in droplet morphology and internal LC organisation, expanding applications in optics, sensing, and active matter. This review highlights the evolution and potential of LC-containing complex emulsions. Emphasis is placed on emulsions featuring dynamic and reversible morphological transformations and LC reorganisation, underpinning their suitability for tunable micro-lenses, chemical sensing, and biosensing. Nematic LCs within complex emulsions allow for topological defect-driven functionalization, attaching antibodies to induce substantial changes in the LC director field upon interfacial recognition events. This feature may facilitate the development of ultrasensitive chemical and biological sensors. Moreover, cholesteric LCs, through their selective reflection, enable the rapid and sensitive detection of foodborne pathogens. The controlled assembly of magnetic nanoparticles at interfaces illustrates advancements towards magnetic field-responsive and active colloids. Future perspectives include exploiting these properties for intelligent colloidal systems capable of autonomous behaviour, and furthering applications in dynamic photonic devices, high-security identification tags, and responsive lens systems.

The construction of COFs functionalized CRISPR electrochemical sensor for ultrasensitive detection of bacteria by hyper-branched rolling circle amplification

Rapid, sensitive, and low-cost foodborne pathogens detection is crucial for dealing with foodborne diseases caused by bacteria. In this work, we designed a new CRISPR/Cas9-mediated electrochemical biosensor for ultrasensitive detection of Escherichia coli (E. coli) based on multifunctional covalent organic framework-based nanocomposite (GOx-AuNPs-COF-H2) and hyperbranched rolling circle amplification (HB-RCA) reaction. When specific DNA targets were present in the system, the targets could be recognized and cleaved by CRISPR-Cas9 system, which triggered strand displacement reaction (SDR) and HB-RCA reaction. By introducing GOx-AuNPs-COF-H2 nanocomposite, H2 probe could hybridize with RCA products to bind to the electrode surface. After added glucose solution, GOx could catalyze it in the detection system and thus offered significant current signals for bacteria detection. This approach showed high analytical performance for assay of E. coli with the detection limit (LOD) of 10 CFU/mL. Furthermore, real samples were detected by this approach, demonstrating its promising potential for foodborne pathogens detection in food monitoring and clinical diagnosis.

DNA and ATP synergistically triggered Argonaute-mediated sensor for the ultrasensitive detection of viable Salmonella without DNA extraction and amplification

Foodborne pathogens present a significant threat to human health. In this study, a phage-assisted DNA and ATP synergistically triggered Argonaute-mediated fluorescent (PDAAF) biosensor was developed for the ultrasensitive detection of viable Salmonella with DNA extraction-free and amplification-free. The phage can lyse viable Salmonella to release DNA and ATP, which can reflect the amount of bacteria present. First, the two-step cleavage ability of Pyrococcus furiosus Argonaute (PfAgo) was used to identify the target DNA and cleave fluorescent probes. Second, the bivalent aptamer recognized the ATP and released guide DNA that combined with PfAgo to cleave fluorescent probes. The DNA and ATP synergistically triggered double cleavage in a single tube, greatly enhancing the detection sensitivity for Salmonella (limit of detection was 20 CFU/mL). The spiked recoveries (87.72%-113.97%) and real sample analysis demonstrated that the PDAAF biosensor possesses good accuracy and applicability, effectively enabling the DNA extraction- and amplification-free detection of foodborne pathogens.

Antibody functionalized capacitance sensor for label-free and real-time detection of bacteria and antibiotic susceptibility

The effective management of infectious diseases and the growing concern of antibiotic resistance necessitates accurate and targeted therapies, highlighting the importance of antibiotic susceptibility testing. This study aimed to develop a real-time impedimetric biosensor for identifying and monitoring bacterial growth and antibiotic susceptibility. The biosensor employed a gold 8-channel disk-shaped microelectrode array with specific antibodies as bio-recognition elements. This setup was allowed for the analysis of bacterial samples, including Staphylococcus aureus, Bacillus cereus, and Micrococcus luteus. These microorganisms were successfully cultured and detected within 1 h of incubation even with a minimal bacterial concentration of 10 CFU/ml. Overall, the developed biosensor array exhibits promising capabilities for monitoring S. aureus, B. cereus and M. luteus, showcasing an excellent linear response ranging from 10 to 104 CFU/ml with a detection limit of 0.95, 1.22 and 1.04 CFU/mL respectively. Moreover, real-time monitoring of antibiotic susceptibility was facilitated by changes in capacitance, which dropped when bacteria were exposed to antibiotic doses higher than their minimum inhibitory concentration (MIC), indicating suppressed bacterial growth. The capacitance measurements enabled determination of half-maximal cytotoxic concentrations (CC50) values for each bacteria-antibiotic pair. As a proof-of-concept application, the developed sensor array was employed as a sensing platform for the real time detection of bacteria in milk samples, which ensured the reliability of the sensor for in-field detection of foodborne pathogens and rapid antimicrobial susceptibility tests (ASTs).

A novel specific fluorescent biosensor for detection of foodborne pathogens based on split crRNA of CRISPR/Cas12a

A novel CRISPR/Cas12a biosensor for specific detection of pathogenic bacteria was constructed based on target nucleic acid (NA) inducing transcription-unleashed split crRNA. Two NA sites of bacterial 16S rRNA were bound to specific probes to induce transcription of large amounts of split crRNA, namely crRNA1 and crRNA2. The amplified crRNA1 and crRNA2 formed a complex with Cas12a and single-strand (ss) DNA activators. Then, Cas12a mediated trans cleavage of the ssDNA reporter molecules, which produced a fluorescent signal. Under optimum conditions, the developed fluorescent biosensor for detection of Staphylococcus aureus showed excellent performance with a low detection limit of 21 CFU/mL and a wide linear range of 103–106 CFU/mL. The proposed biosensor was sensitive and specific for detection of Staphylococcus aureus in spiked milk samples.

Microscopic identification of foodborne bacterial pathogens based on deep learning method

Accurate and rapid detection of foodborne bacterial pathogens is critical for food quality control. Nowadays, tracking morphological bacterial properties using microscope is still a priority at the grass-roots food supervision department due to its simplicity and low cost. However, the method requires highly professional personnel and there are certain misjudgments in the process of analysis. Automatically recognizing foodborne pathogen using deep learning algorithm to replace manual microscopy will not only reduce expert cost, artificial misjudgment, and operation time in detection, but also provide more objective and accurate identification. Here, we firstly constructed a high-quality and large-scale dataset of foodborne pathogenic bacteria, allowing the deep learning-based model to be efficiently trained and achieve accurate identification. The deep convolutional neural network-based model is capable of identifying six common foodborne pathogens, including Escherichia coli (O157:H7), Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, Salmonella typhi, and Streptococcus hemolyticus, with accuracy rates of 90%–100%. This method can assist or replace the manual microscopic inspection step in traditional detection methods, and is promising to break through the traditional approach that heavily relies on manual judgment, greatly reduce the cost of experts and human errors, and provide rapid, accurate, and powerful discriminatory results in large quantities for detection.

An ultrasensitive smartphone-assisted bicolor-ratiometric fluorescence sensing platform based on a “noise purifier” for point-of-care testing of pathogenic bacteria in food

Non-specific binding in fluorescence resonance energy transfer (FRET) remains a challenge in foodborne pathogen detection, resulting in interference of high background signals. Herein, we innovatively reported a dual-mode FRET sensor based on a “noise purifier” for the ultrasensitive quantification of Escherichia coli O157:H7 in food. An efficient FRET system was constructed with polymyxin B-modified nitrogen-sulfur co-doped graphene quantum dots (N, S-GQDs@PMB) as donors and aptamer-modified yellow carbon dots (Y-CDs@Apt) as acceptors. Magnetic multi-walled carbon nanotubes (Fe@MWCNTs) were employed as a “noise purifier” to reduce the interference of the fluorescence background. Under the background purification mode, the sensitivity of the dual-mode signals of the FRET sensor has increased by an order of magnitude. Additionally, smartphone-assisted colorimetric analysis enabled point-of-care detection of E. coli O157:H7 in real samples. The developed sensing platform based on a “noise purifier” provides a promising method for ultrasensitive on-site testing of trace pathogenic bacteria in various foodstuffs.

Autoluminescent Met-AuNCs mediated coreactant-free electrochemiluminescent biosensor based on DNA walker cascade signal amplification for Vibrio parahaemolyticus detection

Most electrochemiluminescent (ECL) biosensors currently necessitate coreactants that affect sensor detection accuracy and increase sensor construction complexity. This study detailed the creation of an ECL biosensor without coreactant, utilizing Methionine-capped Au nanoclusters (Met-AuNCs) as luminophore and a Pb2+-dependent DNAzyme-mediated DNA walker signal amplification strategy to detect Vibrio parahaemolyticus (Vp) in scallops. Double-stranded DNA (dsDNA) was produced through hybridization of the Vp aptamer with DNA walker. The electrode surface was loaded with cDNA labeled with Met-AuNCs. Upon the presence of Vp, it competitively bound to the aptamer, resulting in dsDNA dissociation and exposing the DNAzyme sequence in the DNA walker. The introduction of Pb2+ initiated the activation and circulation of the DNAzyme-mediated DNA walker on the electrode surface, causing the cDNA to be sheared. As a result, the cDNA-Met-AuNCs on the surface of the electrode decreased, resulting in a reduction of ECL signal intensity. The ECL biosensor detected Vp at a range of 1.00×101-1.00×107 CFU/mL, under optimal conditions, with the limit of detection (LOD) being 1.23 CFU/mL. In this work, the biosensor demonstrated excellent stability and specificity and had proven successful in detecting actual samples of aquatic products. This study offers a novel ECL method without a coreactant for the detection of foodborne pathogens in aquatic products.

Dual-Readout Ultrasensitive Lateral Flow Immunosensing of Salmonella typhimurium in Dairy Products by Doping Engineering-Powered Nanoheterostructure with Enhanced Photothermal Performance.

The photothermal lateral flow immunoassay (LFIA) is of great significance to suitable for on-site semiquantitative detection, which has the upper hand in further constructing detection methods for low-concentration targets. Herein, we presented a doping engineering-powered nanoheterostructure with an enhanced photothermal performance strategy, employing bimetallic nanocuboid Pt3Sn (PSNCs) as a proof of concept. With the help of finite element simulation analysis, the contrast of direct temperature experiment, and the evaluation of photothermal conversion efficiency (η), the distinguished and enthusiastic photothermal feedback of PSNCs is proved. Based on steady bright black of colorimetric and superior photothermal performance, the PSNCs were employed to construct an ultrasensitive model LIFA for detecting Salmonella typhimurium (S. typhimurium), which achieved the double-signal semiquantitative detection, the detection limit reached 103 cfu mL-1 (colorimetric mode) and 102 cfu mL-1 (photothermal mode), which is 100 times higher than that of the traditional colloidal gold method. In addition, the method was effective for the detection of targets in dairy samples only through a simple dilution treatment, which was completed within 15 min. Meanwhile, this PSNCs dual-signal LFIA demonstrated the sensitive detection of S. typhimurium due to the excellent colorimetric signal and significant photothermal performance, which provides a broad spectrum for the future detection of foodborne pathogens.