Establishment of highly sensitive lateral flow immunochromatographic strips for quinclorac detection utilizing signal amplification nanoparticles.

Highly selective herbicide quinclorac (Qui) is a type of quinoline carboxylic acid hormone herbicide, which has the characteristics of long half-life and difficulty for degradation, causing high risk to the environmental safety. In this study, anti-Qui 8A3 monoclonal antibody (mAb) with good specificity and high affinity (3.89 × 109 L/mol) was prepared, and two kinds of lateral flow immunochromatographic strips (LFICS) including nano-flower nanoparticles (AuNF) - and latex microsphere (LM)- based LFICS were established based on the antibody and signal amplification. The linear range of the AuNF- and LM- based LFICS were 5.31-345.48 ng/mL and 2.52-257.92 ng/mL, respectively. The limit of detection (LOD) of the AuNF- and LM- based LFICS were determined to be 5.31 ng/mL and 2.52 ng/mL, respectively. In summary, the developed LFICS using AuNF and LM as signal amplification reporters exhibited excellent sensitivity and provided the rapid on-site screening of Qui and other analytes in food safety field.

Development of a colloidal gold immunochromatographic test strip for detecting the smooth Brucella.

Brucellosis, caused by Gram-negative Brucella, spreads in human and animal populations through contact with infected animals and products. Developing a rapid and sensitive detection technology for pathogen is crucial to reduce the risk of this disease transmitting between animal populations and to humans. We produced a monoclonal antibody LPS-6B5, which shows high affinity to LPS and limited cross-reactivity with other bacteria. Based on LPS-6B5, a colloidal gold immunochromatographic assay (GICA) was developed which demonstrates high sensitivity and specificity in detecting cultured B. melitensis, B. abortus and B. suis. The Gold Immunochromatographic Assay (GICA) strips exhibited the most sensitive detection limits, with a value of 7.8125 × 105 CFU/mL for Brucella melitensis, surpassing the sensitivity levels observed for Brucella abortus and Brucella suis. It is also suitable for clinical and field samples, providing a cost-effective and user-friendly alternative to traditional methods.

Neutrophil extracellular traps protect the kidney from ascending infection and are required for a positive leukocyte dipstick test.

Lower urinary tract infection (UTI) is common but only rarely complicated by pyelonephritis. However, the mechanisms preventing extension to the kidney are unclear. Here, we identified neutrophil extracellular traps (NETs) in healthy human urine that provide an antibacterial defense strategy within the urinary tract. In both in vivo murine models of UTI where uropathogenic E. coli are inoculated into the bladder and ex vivo human urine models, NETs interacted with uromodulin to form large webs that entrapped the bacteria. Peptidyl arginine deiminase 4 (PADI4) inhibition in mice blocked NETosis and resulted in progression of cystitis into pyelonephritis, suggesting that NETosis of urinary neutrophils acts to prevent bacterial ascent into the kidney. Analysis of UK Biobank data revealed that genetic variants in PADI4 that associated with increased risk of rheumatoid arthritis in multiple genome-wide association studies were consistently associated with reduced susceptibility to UTI. Last, we showed that urine dipstick testing for leukocyte esterase was negative in the presence of intact blood neutrophils but became positive when neutrophils were stimulated to NET, and this could be prevented by selective PADI4 inhibition, demonstrating that this test does not detect absolute neutrophil count, as has long been assumed, but specifically detects neutrophils that have undergone NETosis. These findings highlight the role of NETosis in preventing ascending infections in the urinary tract and improve our understanding of one of the most common clinical tests in medicine.

Preparation and preliminary application of fluorescent microsphere test strips for feline parvovirus antibodies.

This study introduces a novel diagnostic modality for the detection of feline panleukopenia virus (FPV) antibodies in feline serum by using fluorescent microsphere immunochromatographic test strips (FM-ICTS). Leveraging the inherent specificity of antigen-antibody interactions, the FM-ICTS approach demonstrates considerable potential for efficient and accurate FPV antibody detection within a short timeframe. The FM-ICTS method demonstrates strong diagnostic performance, with consistent accuracy and stability over time. PBS buffer dilution enables detection across the range of FPV antibody haemagglutination inhibition (HI) titres in both healthy and immunized or infected cats. A high correlation (R² = 0.9733) between the T/C ratio and FPV antibody titres confirms the method's effectiveness in quantifying these titres. Clinical validation with 84 samples supports its reliability by matching results with HI assays. Additionally, stability tests show that the test strips maintain performance during storage, with a coefficient of variation (CV) below 12% over three months at 25℃. This innovative FM-ICTS framework emerges as a promising avenue for expedient and dependable disease diagnosis within the realm of veterinary science, offering implications for timely disease management and surveillance.

Evaluating fentanyl test strips as a harm reduction strategy in rural and urban counties: study protocol for a randomized controlled trial.

BACKGROUND: Opioid-related fatalities are a leading cause of death in Ohio and nationally, with an increasing number of overdoses attributable to fentanyl. Rapid fentanyl test strips can identify fentanyl and some fentanyl analogs in urine samples and are increasingly being used to check illicit drugs for fentanyl before they are used. Fentanyl test strips are a promising harm reduction strategy; however, little is known about the real-world acceptability and impact of fentanyl test strip use. This study investigates fentanyl test strip distribution and education as a harm reduction strategy to prevent overdoses among people who use drugs. METHODS: The research team will recruit 2400 individuals ≥ 18 years with self-reported use of illicit drugs or drugs purchased on the street within the past 6 months. Recruitment will occur at opioid overdose education and naloxone distribution programs in 16 urban and 12 rural Ohio counties. Participating sites will be randomized at the county level to the intervention or non-intervention study arm. A brief fentanyl test strip educational intervention and fentanyl test strips will be provided to participants recruited from sites in the intervention arm. These participants will be eligible to receive additional fentanyl test strips for 2 years post-enrollment. Participants recruited from sites in the non-intervention arm will not receive fentanyl test strip education or fentanyl test strips. All participants will be followed for 2 years post-enrollment using biweekly, quarterly, and 6-month surveys. Primary outcomes include (1) identification of perceived barriers and facilitating factors associated with incorporating fentanyl test strip education and distribution into opioid overdose education and naloxone distribution programs; (2) differences in knowledge and self-efficacy regarding how to test drugs for fentanyl and strategies for reducing overdose risk between the intervention and non-intervention groups; and (3) differences in non-fatal and fatal overdose rates between the intervention and non-intervention groups. DISCUSSION: Findings from this cluster randomized controlled trial will contribute valuable information about the feasibility, acceptability, and impact of integrating fentanyl test strip drug checking in rural and urban communities in Ohio and help guide future overdose prevention interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT05463341. Registered on July 19, 2022. https://clinicaltrials.gov/study/NCT05463341.

A lateral strip assay for ultrasensitive detection of glyphosate in soybeans and corn.

Glyphosate (GLY) is widely applied in agriculture and horticulture as a herbicide. The development of genetically modified plants has caused abuse of GLY, with excessive residues potentially causing harm to human health. Consequently, a novel method needs to be built to detect GLY in soybeans and corn. Computer simulation was used to design an excellent hapten which was used to produce an anti-GLY monoclonal antibody (mAb) with outstanding sensitivity and affinity, and its 50%-inhibitory concentration (IC50) was 128.59 ng mL-1. Afterwards, an immunochromatographic assay strip was developed based on the mAb. In soybeans and corn, the visual detection limits were 1 mg kg-1 and 0.2 mg kg-1, while the cut-off values were 50 mg kg-1 and 5 mg kg-1, respectively. The reliability of the strips was proved by the existing methods. Thus, a rapid method to detect GLY residues on-site in soybeans and corn was established.

Development of gold nanoparticle-based lateral-flow strips for NGAL protein detection in urine samples.

This study focuses on enhancing the sensitivity of lateral-flow strips (LFSs) based on gold nanoparticles (AuNPs) for the detection of Neutrophil Gelatinase-Associated Lipocalin (NGAL) protein in urine samples. Several sizes of AuNP-based LFS biosensors were tested to optimize colorimetric signals for NGAL detection based on improved conjugation conditions. AuNPs of 39.8 nm diameter at pH 8 were the most sensitive for the detection of NGAL. Through systematic enhancements to the AuNP-based LFS, the study significantly improves the sensitivity, enabling the reliable detection of NGAL protein in urine samples at a level as low as 12.5 ng mL-1. These advances contribute to the refinement of diagnostic tools for the early detection of kidney injury, specifically in cases associated with the presence of NGAL protein, offering a more precise and effective screening approach.

Prevalence and correlates of fentanyl test strip use among people who use drugs in Rhode Island.

BACKGROUND: Illicitly manufactured fentanyl accounts for a majority of overdose fatalities in the US. Research has demonstrated that fentanyl test strips (FTS) help people who use drugs (PWUD) avoid unintended exposure to fentanyl and overdose. This study assesses characteristics associated with FTS use among PWUD in Rhode Island. Such findings may shed light on whether there are subgroups of PWUD who are less likely to be using FTS and therefore may benefit from their use. METHODS: From September 2020 - February 2023, participants were recruited to participate in RAPIDS, a clinical trial assessing whether FTS provision can reduce overdose rates. Baseline data were used to assess correlates of lifetime FTS use through bivariable and multivariable analyses. We also examined drug testing patterns relating to FTS use in the past month. RESULTS: Of 509 people enrolled, 376 (73.9 %) had heard of FTS before enrollment. Among this group, 189 (50.3 %) reported lifetime FTS use and 98 (26.1 %) reported use in the last month. In bivariable analyses, lifetime injection drug use, responding to an overdose, and drug selling were associated with FTS use. Solitary drug use was not associated with FTS uptake. In the multivariable analysis, gender and lifetime naloxone administration were associated with FTS use. Of those who used FTS in the past month, 76.5 % had at least one test that was positive for fentanyl. CONCLUSIONS: We found high uptake of FTS use among PWUD in Rhode Island. Our results also suggest a need for targeted outreach to increase FTS uptake among sub-groups of PWUD. CLINICAL TRIAL REGISTRATION: The Rhode Island Prescription and Illicit Drug Study is a registered clinical trial, NCT043722838.

Evaluation of a Diazo-Based Point-Of-Care Bilirubin Assay careSTART S1 Total Bilirubin Strip.

BACKGROUND: Neonatal jaundice (NNJ) affects a significant proportion of newborns globally, with an increased burden in low-resource settings. Effective health risk management of NNJ is hindered, particularly in resource-constrained environments, where early detection and treatment are challenging. The careSTART S1 Total Bilirubin Strip, a point-of-care testing (POCT) device based on a diazo-method, offers a potential solution by enabling onsite bilirubin measurement, thus, addressing the gap in early NNJ detection and management. METHODS: The current study evaluated the analytical performance of the careSTART S1 Total Bilirubin Strip for precision, linearity, method comparison, and lot-to-lot consistency following CLSI guidelines. For method comparison, 105 residual EDTA whole blood samples were analyzed with the careSTART S1 Total Bilirubin Strip and compared with reference measurements from the Roche Cobas c702 analyzer. Additionally, statistical analyses, including Passing-Bablok regression and Bland-Altman plots, were performed. RESULTS: The careSTART S1 Total Bilirubin Strip showed allowable (<10%) within-laboratory imprecision of 2.5%-3.6% across all levels and demonstrated linearity over the range of 4.16-439.3 µmol/L. Method comparison revealed a constant negative bias with a mean bias -4.19 µmol/L. However, the 95% confidence interval (-7.10 to -1.28 µmol/L) of the bias is covered by the prespecified allowable bias of 8.3%, at medical decision point. Lot-to-lot variation ranged from 0.14%-6.49%, and was within the acceptable critical difference of 8.3%. CONCLUSION: The careSTART S1 Total Bilirubin Strip provided accurate and reliable bilirubin measurements that could contribute to neonatal care in settings lacking central laboratory facilities.

Determining the accuracy of the leukocyte esterase reagent strip test in the rapid diagnosis of adult septic arthritis.

BACKGROUNDS: Septic arthritis is a dangerous disease that occurs when microorganisms enter synovial fluid. It needs fast and accurate management; otherwise, it can harm the patient's life. Currently, the tests measure WBC and PMN in SF, so we hypothesized to use a proxy that is easier and faster to measure. Leukocyte esterase is an enzyme secreted by neutrophils that can be found in the synovial fluid of SA patients. In this study, we tried to investigate the sensitivity and specificity of leukocyte esterase in diagnosing septic arthritis. METHODS: We obtained synovial fluid samples from forty-six patients suspected of having septic arthritis and fifty-eight healthy individuals and measured the WBCs, ESR, CRP, PMN, glucose, and protein of SF in 2021. We also used the leukocyte esterase dipstick test to investigate the level of LE in synovial fluid for one minute. RESULTS: Based on clinical and paraclinical criteria, sixteen out of the forty-six patients were diagnosed with SA. When (++) was considered positive, the sensitivity and specificity of the LE dipstick test for the diagnosis of SA were 93.7% (95% CI: 81.8-100%) and 60% (95% CI: 42.4-77.5%, P = 0.000), respectively. When both (+) and (++) were considered positive, they were 100% and 43.3% (95% CI: 25.6-61.0% P = 0.000), respectively. All the patients in the control group had negative cultures and LE test readings (specificity = 100%). CONCLUSION: The LE dipstick test can be a valuable diagnostic tool in the initial diagnosis of SA since it is affordable, fast, and reliable.

A sensitive intelligent point-of-care test method for tert-butylhydroquinone in edible oil via a test strip with a smartphone.

Tert-butylhydroquinone (TBHQ) is easily overused or illegally added to edible oil and attracts a growing concern because of its cytotoxic, liver-damaging, and carcinogenic effects. Thus, a sensitive and intelligent point-of-care testing (iPOCT) method is developed to fulfill the on-site monitoring. This iPOCT method depended on a fluorescent immunochromatographic assay within 15 min. Under optimization, the limit of quantification (LOQ) was calculated as 0.03 µg mL-1. The iPOCT method provided a low limit of detection (LOD) of 0.02 µg mL-1, a wide linear range of 0.03-100 µg mL-1, and great selectivity. Recoveries by the spiking experiments ranged from 97.4% to 103.5% with relative standard deviations (RSDs) of 2.4%-4.9% in soybean, peanut, rapeseed, and corn oil samples. The results showed that the iPOCT method is highly consistent with the high-performance liquid chromatography (HPLC) method.

Development of quantum dot-based immunochromatographic strip for detection of antibodies against ASFV pp62.

ASFV is the only known double-stranded insect-borne DNA virus, which can rapidly infect domestic pigs and wild boars with ticks as transmission medium. Since it was first discovered in 1921, it quickly spread to all parts of the world and brought huge economic losses to the pig industry all over the world. At present, there is still no safe and effective vaccine for ASFV. Here, we developed a quantum-dot labeled antibody test strip for the detection of antibodies against ASFV pp62. The pp62 protein was labeled with quantum dots, and the antibody test strip was developed uses it in a detection mode of labeled antigen-SPA interceptor-monoclonal antibody quality control. The test strip showed high sensitivity, the positive detection limit of the strip was 1: 106 by continuous multiple dilution using the positive standard serum of ASFV antibody as reference. The test strip showed good specificity, and there was no cross reaction with other swine diseases virus (PCV2, PRRSV, CSFV, PPV). Using the detection results of commercialized kit for African swine fever virus as reference, 80 ASFV antibody negative serum and 4 different ASFV antibody positive serum were detected using the ASFV pp62 quantum-dot labeled antibody test strip. The results were consistent with the commercial kit. This study provides a new detection method for the prevention and control of African swine fever.

Development of a simple and rapid dipstick paper-based test strip for colorimetric determination of nitrate and nitrite in water and foodstuffs.

A rapid user-friendly paper-based test strip using zinc microparticles in conjugation with Griess reagent was developed for nitrite and nitrate detection. Test strips were fabricated using a simple and fast method of step-by-step immersion into reagents so that each strip contained a single detection pad for nitrite detection and another separate pad for nitrate detection. To reduce nitrate to nitrite, zinc microparticles suspended in ethanolic solution of polyvinylpyrrolidone (PVP) were uniformly immobilized on the paper strips that were previously impregnated in the Griess reagent and dried. The Griess reagent components were optimized to reach the highest color intensity. The optimized test strip was able to determine both nitrite and nitrate with respective detection limits of 0.43 and 9.43 mg/kg and a detection time of 60 s. The performance of the new test strips was evaluated for the simultaneous colorimetric detection of nitrite and nitrate in water and different food samples.

Field laboratory comparison of STANDARD Q Filariasis Antigen Test (QFAT) with Bioline Filariasis Test Strip (FTS) for the detection of Lymphatic Filariasis in Samoa, 2023.

BACKGROUND: To monitor the progress of lymphatic filariasis (LF) elimination programmes, field surveys to assess filarial antigen (Ag) prevalence require access to reliable, user-friendly rapid diagnostic tests. We aimed to evaluate the performance of the new Q Filariasis Antigen Test (QFAT) with the currently recommended Filariasis Test Strip (FTS) for detecting the Ag of Wuchereria bancrofti, the causative agent of LF, under field laboratory conditions. METHODOLOGY/PRINCIPAL FINDINGS: During an LF survey in Samoa, 344 finger-prick blood samples were tested using FTS and QFAT. Microfilariae (Mf) status was determined from blood slides prepared from any sample that reported Ag-positive by either Ag-test. Each test was re-read at 1 hour and the next day to determine the stability of results over time. Overall Ag-positivity by FTS was 29.0% and 30.2% by QFAT. Concordance between the two tests was 93.6% (kappa = 0.85). Of the 101 Mf slides available, 39.6% were Mf-positive, and all were Ag-positive by both tests. Darker test line intensities from Ag-positive FTS were found to predict Mf-positivity (compared to same/lighter line intensities). QFAT had significantly higher reported test result changes than FTS, mostly reported the next day, but fewer changes were reported between 10 minutes to 1hour. The field laboratory team preferred QFAT over FTS due to the smaller blood volume required, better usability, and easier readability. CONCLUSION/SIGNIFICANCE: QFAT could be a suitable and user-friendly diagnostic alternative for use in the monitoring and surveillance of LF in field surveys based on its similar performance to FTS under field laboratory conditions.

Use of strips of rapid diagnostic tests as a source of ribonucleic acid for genomic surveillance of viruses: an example of SARS-CoV-2.

BACKGROUND: This study aimed to demonstrate that the genomic material of SARS-CoV-2 can be isolated from strips of COVID-19 rapid diagnostic test cassettes. METHOD: It was a prospective cross-sectional study involving patients admitted to treatment centers and sampling sites in the city of Conakry, Guinea. A total of 121 patients were double sampled, and 9 more patients were tested only for RDT. PCR was conducted according to the protocol of the RunMei kit. Sequencing was performed by using the illumina COVIDSeq protocol. Nine COVID-19 RDTs without nasopharyngeal swabs were in addition tested. RESULT: Among the 130 COVID-19 RDTs, forty-seven were macroscopically positive, whereas seventy-two were positive according to PCR using RDT strip, while among the 121 VTM swabs, sixty-four were positive. Among eighty-three negative COVID-19 RDTs, twenty-seven were positive by PCR using RDT strip with a geometric mean Ct value of 32.49 cycles. Compared to those of PCR using VTM, the sensitivity and specificity of PCR using RDT strip were estimated to be 100% and 85.96%, respectively, with 93.39% test accuracy. Among the fifteen COVID-19 RDT extracts eligible for sequencing, eleven had sequences identical to those obtained via the standard method, with coverage between 75 and 99.6%. CONCLUSION: These results show that COVID-19 RDTs can be used as biological material for the genomic surveillance of SARS-CoV-2.

Development and Application of Colloidal Gold Test Strips for the Rapid Detection of Canine Brucellosis.

Brucellosis is a global problem, with the causative agent being the genus Brucella. B. canis can cause undulant fever in dogs, which is a zoonotic disease that can spread not only among dogs but also to humans. This poses a public health threat to society. In this study, a rapid and straightforward immune colloidal gold test strip was developed for the diagnosis of canine brucellosis through the detection of anti-LPS antibodies in serum samples. Rabbit anti-canine IgG conjugated with colloidal gold was employed as the colloidal gold-labeled antibody. The extracted high-purity R-LPS was employed as the capture antigen in the test line (T-line), while goat anti-rabbit IgG was utilized as the capture antibody in the control line (C-line). The colloidal gold strip exhibited high specificity in the detection of brucellosis, with no cross-reaction observed with the common clinical canine diseases caused by Canine coronavirus (CCV), Canine distemper virus (CDV), and Canine parvovirus (CPV). In comparison to the commercial iELISA kit, the sensitivity and specificity of the colloidal gold test strip were found to be 95.23% and 98.76%, respectively. The diagnostic coincidence rate was 98.47%. The findings of this study indicate that colloidal gold test strips may be employed as a straightforward, expeditious, sensitive, and specific diagnostic instrument for the identification of canine brucellosis, particularly in resource-limited regions.

Nitazene test strips: a laboratory evaluation.

BACKGROUND: 2-Benzylbenzimidazole 'nitazene' opioids pose a growing threat to public health. Nitazene analogues are increasingly found mixed with or (mis)sold as heroin and in falsified (non-)opioid medications, posing a great risk of intoxication in users (un)knowingly exposed to these potent opioids. Lateral flow immunoassay nitazene test strips (NTS; BTNX Rapid Response™) became commercially available in Q1 2024, with the aim to enable rapid detection of nitazene analogues in drug samples. As only limited independent data is available on the performance of these strips, this lab-based study aimed at evaluating their potential for drug checking applications. METHODS: Following dilution of drug standards in water, the NTS readouts were analyzed independently by two individuals and by ImageJ. The limit of detection for isotonitazene was determined using two manufacturing lots of NTS. Cross-reactivity with 32 other nitazene analogues was evaluated. Six sourced drug samples were tested to explore the ability of NTS to detect the presence of a nitazene analogue in authentic samples. RESULTS: The limits of detection for isotonitazene were 2000 or 3000 ng/mL, depending on the lot. Twenty-four of the 33 tested nitazene analogues cross-reacted with the NTS at concentrations ≤ 9000 ng/mL. Structural analysis indicated that either substitution or removal of the 5-nitro group, or lengthening the linker between the two aromatic rings, generally hampered detection. All six authentic drug samples consistently tested positive, with no observed false negatives. CONCLUSIONS: This study provides a better understanding of the potential of NTS for drug checking purposes. Our findings indicate that NTS can theoretically alert to the presence of most nitazene analogues that have emerged on recreational drug markets. However, 'desnitazenes' (lacking the 5-nitro group) may yield false negative results due to low cross-reactivity. Although factors like specificity, lot-to-lot variability, nitazene analogue content in drug samples, solubility, and different testing conditions should be considered, our study results indicate that, at least under the conditions evaluated here (using reference standards and sourced powders), NTS are capable of detecting the presence of a wide range of nitazene analogues. Hence, NTS may alert users of the presence of nitazene analogues in drug samples.

Efficient and fast detection of uric acid based on a colorimetric sensing method.

The uric acid (UA) level is an important physiological indicator of the human body, and its abnormality can lead to a series of diseases. Therefore, the immediate detection of uric acid concentration has broad application prospects. Commonly used methods for the analysis of uric acid include chromatography, high-performance capillary electrophoresis and electrochemical methods. However, these methods have the disadvantages of cumbersome sample pre-treatment, high cost, time-consuming, and the need for experimental instruments and professional operators, which are extremely unfavorable for the detection of uric acid and the diagnosis of related diseases in resource-limited areas. In this study, a portable visualization method was developed for the detection of uric acid using hydrogen peroxide (H2O2) test strips. Uric acid enzyme specifically catalyzes the oxidation of uric acid to produce H2O2, which causes a significant change in the color of the H2O2 test strip. The response has good linearity in the range of 1 ∼ 50 µg mL-1. Thus, it provides a simple, rapid, and cost-effective visualized bioassay for uric acid.

A lot testing protocol for quality assurance of fentanyl test strips for harm reduction applications.

Fentanyl test strips (FTS) are lateral flow immunoassays that were originally designed and validated for detecting low concentrations of fentanyl in urine. Some FTS are now being marketed for the harm reduction purpose of testing street drugs for the presence of fentanyl. This manuscript provides a simple protocol to assess whether different brands and lots of fentanyl test strips perform adequately for use in drug checking. The results gathered from this protocol will document problems with particular lots or brands of FTS, help buyers choose from among the array of products, provide feedback to manufacturers to improve their products, and serve as an early warning system for ineffective products.

Multifunctional Fe3O4@CuS nanoparticle-driven colorimetric and photothermal immunochromatographic test strip for the sensitive detection of Salmonella typhimurium in milk.

Magnetic nanoparticles are widely employed as signal labeling reporters in immunochromatographic test strips (ICTS) for detecting foodborne pathogens due to their outstanding anti-interference and magnetic enrichment performance. However, the insufficient colorimetric signal brightness of magnetic nanoparticles results in poor sensitivity, hindering their ability to meet the growing demand for advanced ICTS. Herein, we synthesized Fe3O4@CuS core-shell structure nanoparticles using a facile in-situ growth method. These Fe3O4@CuS nanoparticles exhibit a superior photothermal conversion efficiency of 42.12 % and a magnetization strength of 35 emu/g. We developed a dual-readout format ICTS based on Fe3O4@CuS, incorporating both colorimetric and photothermal formats to enhance sensitivity for Salmonella typhimurium detection. The limit of detection for Fe3O4@CuS-ICTS in the colorimetric and photothermal format was 5 × 104 CFU/mL and 7.7 × 10³ CFU/mL, respectively. Additionally, the average recoveries ranged from 91.25 % to 103.39 %, with variations from 2.2 % to 11.1 %, demonstrating good accuracy and precision. Therefore, this work suggests that Fe3O4@CuS nanoparticles, with their superior magnetic, optical, and photothermal properties, can serve as promising signal labeling reporters to improve the detection performance of ICTS and hold potential for constructing more accurate and sensitive point-of-care testing platforms.