Immunochromatographic Strip Test Research Articles

Novel time-resolved fluorescent-based multiplex immunochromatography test strip for simultaneous detection of pesticides in vegetables

Novel time-resolved fluorescent-based multiplex immunochromatography test strip for simultaneous detection of pesticides in vegetables

Au Nanoparticles-Trisbipyridine Ruthenium(II) Nanoaggregates as Signal-Amplifying SERS Tags for Immunoassay of cTnI.

Acute myocardial infarction (AMI) is one of the leading causes of human mortality worldwide. In the early stages of AMI, the patient's electrocardiogram (ECG) may not change, so the fast, sensitive, and accurate detection of the specific biomarker of cardiac troponin I (cTnI) is of great importance in the early diagnosis of AMI. In this work, for the first time, electrostatic nanoaggregates of negatively charged Au nanoparticles and positively charged trisbipyridine ruthenium(II) ions (i.e., (-)AuNPs|[Ru(bpy)3]2+ ENAs) as novel and signal-amplifying surface-enhanced Raman scattering (SERS) tags were synthesized in an easy and rapid (<3 min) way and applied in the highly sensitive, rapid detection of cTnI in human serum by being combined with an immunochromatographic test strip (ICTS). The synthesized (-)AuNPs|[Ru(bpy)3]2+ ENAs exhibited strong SERS activity due to the multiple Raman-active units (three bpy ligands) carried by each [Ru(bpy)3]2+ complex ion and abundant hotspots in each SERS tag. The developed (-)AuNPs|[Ru(bpy)3]2+ ENAs-based SERS-ICTS has been validated to be applicable in detection of cTnI in human serum with excellent sensing performances, such as fast testing (5 min) and a low detection limit (60 pg/mL). It is envisioned that the developed (-)AuNPs|[Ru(bpy)3]2+ ENAs-based SERS-ICTS sensor may have promising applications in point of care testing of various biomarkers in clinic. Additionally, this work may inspire the finding and the application of new types of Raman reporter molecules based on high valent metal-multi ligand coordination compounds like [Ru(bpy)3]2+.

A point-of-care testing strip based on a rationally designed antigen and antibody for fast and reliable Diquat poisoning detection: Ready for clinical application

AbstractDiquat (DQ) is a nonselective quick-acting herbicide, which can directly contaminate humans and the environment during improper use and production. The early diagnosis of DQ poisoning allows for patients to receive timely treatment. Here, a novel monoclonal antibody was screened based on the rational design and synthesis of a DQ hapten and complete antigen. With the custom-designed anti-DQ antibody, we developed a stable and specific immunochromatographic strip to recognize DQ within 10 ∼ 15 min in various biological samples. The test strips could recognize DQ at concentrations as low as 20 ng/mL and be read by the naked eye, reaching the detection level of liquid chromatography-mass spectrometry. Moreover, quantitative methods involving the use of immunochromatographic strips and ELISA were developed to continuously monitor DQ concentrations. DQ and paraquat (PQ) joint test strips were developed to simultaneously measure DQ and PQ. Notably, the clinical performance of the proposed test strips was evaluated in multiple hospitals and public health agencies. Taken together, our study provides the first clinical DQ-targeted colloidal gold immunochromatographic test strips with excellent performance, which are expected to be useful for clinical practice, environmental monitoring, food safety and scientific research.

Detection of AFB1 by Immunochromatographic Test Strips Based on Double-Probe Signal Amplification with Nanobody and Biotin–Streptavidin System

Aflatoxin B1 (AFB1) is highly toxic and difficult to prevent. It is mainly produced by fungi and exists in plants and animals and is classified by the World Health Organization as a class I carcinogen, posing a serious threat to human and animal health. Therefore, it is important to establish an efficient, sensitive, and on-site detection method for AFB1 to protect human health. The immunochromatographic test strip method is simple, sensitive, and can achieve real-time detection. However, traditional immunochromatographic test strips have low sensitivity due to their relatively weak optical properties. In this study, Nb-G8 was biotinylated using a chemical method. Two sizes of gold nanoflowers (AuNFs) were prepared and combined with biotinylated G8 and streptavidin to form two types of probes. These probes were sprayed on gold standard pads and expanded pads, respectively, to enhance the signals through the high affinity interaction between streptavidin and biotin. Under the optimal experimental conditions, the half maximal inhibitory concentration (IC50) of this method was 5.0 ng/mL and the limit of detection (IC10) was 0.03 ng/mL, which increased the sensitivity of the test strip by four-fold compared with that of the traditional biotinylated nanoantibody immunochromatography test strip and had a wider detection range. In conclusion, the use of a high-affinity amplification signal between biotin and streptavidin is a valuable method for the detection of aflatoxin.

A Novel Immunochromatographic Test Strip Using Lanthanide-Labeled Fluorescent Nanoparticles for the Serological Detection of Toxoplasma gondii in Dogs and Cats

Toxoplasma gondii (T. gondii) is an important zoonotic pathogen which induces both acute and chronic toxoplasmosis. Timely diagnosis of T. gondii is crucial for effective disease management. Here, we present a pioneering approach using europium (III)-chelated nanoparticles (EuNPs) in a rapid lateral flow immunochromatographic test strip (ICTS) for detecting T. gondii antibodies in serum samples. By conjugating EuNPs with Staphylococcus aureus protein A, we efficiently captured T. gondii-specific antibodies, which bound to T. gondii antigens on the test line (T-line), generating a distinct fluorescent signal. Employing this novel method, we conducted an extensive epidemiological investigation of T. gondii infections among dogs and cats in Shanghai, China. This innovative ICTS allows for rapid results within 25 min, which include a qualitative result through naked-eye observation under an ultraviolet lamp and a quantitative one derived using a strip reader. With a detection limit of 1:6400 for dog positive serum and no cross-reactivity with other canine and feline pathogens, the EuNPs-ICTS demonstrated excellent consistency with standard enzyme-linked immunosorbent assay results for dogs (κ = 0.91) and cats (κ = 0.92). In addition, 20.38% of 996 dog serum samples and 14.18% of 416 cat serum samples revealed T. gondii antibodies, highlighting the efficacy of this approach. Our study presents a rapid, sensitive, specific, and reproducible EuNPs-ICTS, serving as a promising tool for on-the-spot diagnosis of T. gondii infections in dogs and cats.

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

SummaryBrucellosis, 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.

A highly sensitive Photothermal Immunochromatographic test strip for detection of aflatoxin B1 based on CoS@TA Nanospheres

A novel photothermal immunochromatographic test strip (PITS) with tannic acid (TA) modified cobalt sulfide (CoS) nanospheres (CoS@TA) as immuno-probe element was developed for the detection of aflatoxin B1 (AFB1). CoS nanospheres (CoS NPs) with excellent photothermal conversion efficiency (η = 47.5 %) was synthesized and skillfully chelated with TA to improve its dispersion, biocompatibility, and chromatographic properties. After modification, the CoS@TA coupled with monoclonal antibody (mAb) against AFB1 (CoS@TA-mAb) by simple physical adsorption. The CoS@TA based PITS achieved highly sensitive detection of AFB1 with the limit of detection in photothermal signal (photothermal-LOD) of 0.00503 μg/L, which was 19.88-fold higher than the LOD in visual signal (visual-LOD, 0.1 μg/L). The application of TA in the modification of CoS provided ideas to improve the properties of functional nanomaterials such as dispersion and biocompatibility, and the application of CoS@TA in PITS construction laid a methodological foundation for further improving the detection sensitivity of trace targets.

Fabrication of Core-Shell Quantum Dots Microbeads with high stability, enhanced sensitivity and potential application in C-Reactive Protein (CRP) and Procalcitonin (PCT) Immunochromatography in Vitro Diagnostic Reagents

Cardiovascular and cerebrovascular diseases represent the leading causes of mortality among middle-aged and elderly populations in China, with inflammation identified as a significant contributing factor. Consequently, the early diagnosis and management of inflammation are of paramount importance. C-reactive protein (CRP) and procalcitonin (PCT) serve as biomarkers for myocardial inflammation. In this study, we developed a quantum dot immunochromatographic strip that was capable of simultaneously detecting these two biomarkers with enhanced sensitivity and specificity. The comb amphiphilic poly (octadecyl-alt-polyethylene glycol) was synthesized through an amide reaction, which was employed to coat oil-soluble quantum dots, thereby transforming them into water-soluble quantum dots microbeads suitable for the coupling with biological macromolecules. These quantum dots microbeads were utilized as luminescent materials in the immunochromatographic strip for the concurrent detection of CRP and PCT. The assay required only 100 μL of sample and provided results within 10 minutes, demonstrating commendable precision, stability, sensitivity, and accuracy. Clinical evaluations had confirmed that the developed CRP and PCT quantum dots immunochromatographic test strips were accurate reliable, underscoring their significant potential for practical routine clinical application in the early accurate diagnosis of myocardial inflammation.

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.

Dual-color immunochromatographic test strip for simultaneous sensitive detection of malachite green and leucomalachite green residues in fish and shrimp meat samples

A sensitive dual immunochromatographic test strip (dual-ICTS) was developed to detect malachite green (MG) and its metabolite, leucomalachite green (LMG), using two types of gold nanoparticles: round-shaped (red) and star-shaped (blue). The detection limits were determined to be 0.221 μg L−1 for MG and 0.214 μg L−1 for LMG, respectively. The dual-ICTS provided a cut-off value of 1.8 μg L−1 for MG and LMG detection. The dual-ICTS successfully detected MG and LMG in food samples, with recovery rates ranging from 86 % to 116 %. The dual-ICTS was evaluated by correlation analysis between the proposed assay and the well-established enzyme-linked immunosorbent assay in the MG and LMG detection. This is the first report on the development of the ICTS that can detect both MG and LMG at the same time within only 5 min, making it a sensitive and rapid tool for on-site detection.

Modulating of d-band center in Cu single-atom anchored Co3O4 nanozyme for sensitive immunochromatographic test strip

Immunochromatographic test strip (ITS) has been widely employed for point-of-care diagnoses. However, how to significantly enhance the analytical sensitivity of device-free ITS remains a challenge. Here, we synthesized a Cu single-atom anchored Co3O4 (CuSA/Co3O4) nanozyme that possesses ultrahigh peroxidase-mimicking catalytic activity owing to d-band center upshift mediated by Cu single-atom. Molecular orbital analysis demonstrated that d orbitals in CuSA/Co3O4 have stronger orbital hybridization affinity than Co3O4 to H2O2′s π* orbitals. This reinforces hydroxyl radical (OH) production and provides a stronger catalytic colorimetric signal, which is beneficial for improving the sensitivity of ITS. Moreover, we applied the CuSA/Co3O4 to ITS as a signal reporter for monitoring Xanthomonas oryzae pv. oryzicola (Xoc), the pathogen of rice bacterial leaf streak. The visual limit of detection (LOD) of the developed CuSA/Co3O4-based ITS was as low as 6.4 × 102 CFU mL−1, which is 25-fold more sensitive than the traditional Au nanoparticles (AuNP)-based ITS. Taken together, this work demonstrates the great potential of CuSA/Co3O4 nanocomposite as a signal reporter to improve the sensitivity of ITS for on-site Xoc detection.

A novel peptide pair-based rapid fluorescent diagnostic system for malaria Plasmodium falciparum detection

Advanced diagnostic materials, such as aptamers, are required due to the scarcity of efficient diagnostic antibodies and the low sensitivity of rapid diagnostic kits at detecting the malaria parasite, Plasmodium falciparum. MethodsTwo peptides M2.9 [(KPTAEQTESPELQSAPEN) and M2.17 (KILFNVYSPLGCTCECWV)] were designed using simple epitope prediction tools and modified against the merozoite surface antigen 2 of P. falciparum (Pf.MSP2) by 3-dimensional modeling based on binding affinity. Based on five prediction tools for hydropathy, M2.17 was selected as an appropriate capture peptide. A peptide-based fluorescence-linked immunosorbent assay (FLISA) and a peptide pair-based fluorescent immunochromatographic test strip (FICT) were developed to detect P. falciparum 3D7 (drug-sensitive) and P. falciparum K1 (multi drugs-resistant) strains. ResultsBioinformatic analysis of two peptides demonstrated the potential binding affinity with the merozoite surface protein 2 of P. falciparum (Pf.MSP2) with a positive hydropathy value. The limit of detection (LOD) of FLISA was 10 parasites/μL and of a peptide pair-linked rapid FICT system was 5 and 200 parasites/μL for P. falciparum 3D7 and K1, respectively. Compared to commercial rapid detection systems (RDTs), a peptide pair-linked FICT system exhibited a 20-fold greater efficiency in detecting P. falciparum 3D7 and specifically discriminated another protozoan spp. ConclusionA peptide pair-linked rapid diagnostic strip could be an alternative to conventional RDTs for monitoring wild-type and drug-resistant malaria parasites.

Rapid lateral flow test for Mycobacterium tuberculosis complex and non-tuberculous mycobacteria differentiation

The diagnosis of mycobacterial infections, including both the Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), poses a significant global medical challenge. This study proposes a novel approach using immunochromatographic (IC) strip tests for the simultaneous detection of MTBC and NTM. Traditional methods for identifying mycobacteria, such as culture techniques, are hindered by delays in distinguishing between MTBC and NTM, which can affect patient care and disease control. Molecular methods, while sensitive, are resource-intensive and unable to differentiate between live and dead bacteria. In this research, we developed unique monoclonal antibodies (mAbs) against Ag85B, a mycobacterial secretory protein, and successfully implemented IC strip tests named 8B and 9B. These strips demonstrated high concordance rates with conventional methods for detecting MTBC, with positivity rates of 93.9% and 85.9%, respectively. For NTM detection, the IC strip tests achieved a 63.2% detection rate compared to culture methods, considering variations in growth rates among different NTM species. Furthermore, this study highlights a significant finding regarding the potential of MPT64 and Ag85B proteins as markers for MTBC detection. In conclusion, our breakthrough method enables rapid and accurate detection of both MTBC and NTM bacteria within the BACTEC MGIT system. This approach represents a valuable tool in clinical settings for distinguishing between MTBC and NTM infections, thereby enhancing the management and control of mycobacterial diseases.Key points• Panel of mAbs for differentiating MTB versus NTM• IC strips for diagnosing MTBC and NTM after the BACTEC MGIT• Combined detection of MTP64 and Ag85B enhances diagnostic accuracy

A method development for sertraline detection in the blood

Aim – to develop a method for isolation and determination of sertraline in biological fluids. Material and methods. For the study we used "Zoloft" drug ("Pfizer", USA). The study equipment and substances: liquid chromatograph Shimadzu LC-20 Prominence (Japan) with detector SPD-M20A, gas chromatograph Agilent Technologies (USA) 7890 A / 5977 MSD, (program MassHunter GC-MS ), waters vacuum unit and cartridges for solid-phase extraction Oasis HLB; papain enzymes (MedFloran, Russia); trypsin, chymotrypsin, hyaluronidase (Lidaza) (Samson-Med LLC, Russia); test strips from different manufacturers under trade names: "Be sure", "NarcoCHEC", "FACTOR-MED". Urine samples were obtained after administration of the drug to laboratory animals – guinea pigs. The base of sertraline from a solution of its salt was isolated by liquid-liquid extraction (LLE) with organic solvents and their mixtures at pH = 10, 11 and 12 (pKa sertraline 9.48). Obtaining data on the effectiveness of blood sample preparation methods (liquid-liquid extraction, solid-phase extraction and enzymatic hydrolysis) for sertraline was carried out on enriched model samples of donor blood according to the method proposed by Cheger. Results. Cross-positive urine test results were obtained with immunochromatographic test strips for derivatives of e 1,4-benzodiazepine and synthetic cannabimimetics ("spice"). The study with 1 mg/ml solution of sertraline gave a negative result. Desmethylsertraline, a major metabolite, was detected in the urine, a peak with a retention time of about 12.75 min, the peak of the original substance during the synthesis of sertraline – sertralinimine and the peak of the native sertraline with a retention time of about 12.65 min. A method for detecting sertraline by HPLC has been developed. Conclusion. The use of the enzymatic blood hydrolysis with trypsin allows for increasing the degree of extraction by 1.5 times when compared with liquid-liquid extraction with chloroform, and by 2 times when compared with solid-phase extraction.

Fluorescence immunochromatographic detection of antibodies to the p72 protein of African swine fever virus

The African swine fever virus (ASFV), a highly contagious pathogen responsible for African swine fever (ASF), causes significant economic losses in the global pork industry. Due to its large and complex structure, ASFV remains refractory to commercial vaccine development, necessitating the creation of rapid, sensitive, and specific diagnostic tools for disease control. In this study, quantum dots were conjugated to ASFV p72 protein to establish a fluorescent immunochromatographic assay for detecting ASFV-specific antibodies. The assay test strips contained four adjacent pads arranged sequentially: a sample-application pad, a pad containing mobile antigen-probe conjugate, a nitrocellulose readout pad featuring a test line containing immobilised staphylococcal protein A and a control line containing immobilised monoclonal antibodies against the ASFV p72 protein, and an absorbent pad driving the directional flow of liquid via capillary action. The resulting fluorescence immunochromatographic assay demonstrated highly sensitive and specific ASFV antibody detection in under 15 min. Specificity testing showed no cross-reactivity with serum antibodies against other viruses and sensitivity surpassing that of commercial ASFV antibody colloidal gold immunochromatographic test strips. This novel approach offers rapid detection, excellent specificity, and high sensitivity, and supports the future development of fluorescent immunochromatographic test strips for ASFV antibody detection.

Development of a Sensitive Monoclonal Antibody-Based Colloidal Gold Immunochromatographic Strip for Lomefloxacin Detection in Meat Products.

Lomefloxacin (LOM), an antibiotic crucial for preventing various animal diseases in animal husbandry, can pose serious health risks when found in excessive amounts in meat products. The development of highly specific and sensitive colloidal gold immunochromatographic test strips is essential for the accurate detection of this class of antibiotics. Our study utilized a monoclonal antibody (mAb) assay and immunochromatographic strips to detect lomefloxacin residues in meat products. The results showed minimal cross-reactivity with other structural analogs, with a maximum half inhibitory concentration (IC50) of 0.93 ng/mL and a linear range of 0.38 to 2.3 ng/mL for the indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). The recovery of LOM was 80% to 120%, with an average coefficient of variation below 5%. The immunochromatographic strip test results showed a visual detection limit of 2.5 ng/g, meeting the market requirements for the test. This study highlights the significance of specific and sensitive testing methods for detecting lomefloxacin, ensuring consumers' safety and health.

Rapid detection of OTA and ZEN with dual quantum dots fluorescence immunochromatographic test strip

Rapid detection of OTA and ZEN with dual quantum dots fluorescence immunochromatographic test strip

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.

Multiplex immunochromatographic test strip based on multicolor gold nanoparticles for the simultaneous detection of neomycin, penicillin, and chloramphenicol in food samples

In this study, we demonstrated an approach for the development of multiplex immunochromatographic test strip (MICS) for neomycin (NEO), penicillin (PEN), and chloramphenicol (CAP) detection using three different-colored gold nanoparticles. The gold nanoparticles: gold nanospheres (red), gold nanostars (blue), and gold nanoflowers (black) were applied as labels for MICS fabrication. The proposed MICS achieved a clearly visible limit of detection with cut-off values of 500, 5, and 0.5 μg L−1 for NEO, PEN, and CAP, respectively within only 10 min. Such smartphone-based detection provided a limit of detection of 3.70 μg L−1 for NEO, 0.10 μg L−1 for PEN, and 0.008 μg L−1 for CAP. The analysis of real samples by the developed MICS was well correlated with the enzyme-linked immunosorbent assay and liquid chromatography–mass spectrometry. The proposed MICS has the potential to be used for the simultaneous detection of NEO, PEN, and CAP with rapid, precise, and sensitive results.

A colloidal gold immunochromatography-based method for detecting enramycin residues in feed

To achieve rapid detection of enramycin in feed, we employed the competitive inhibition method to develop a colloidal gold immunochromatographic test strip based on the anti-enramycin A monoclonal antibody (anti-Er.A-mAb). Colloidal gold probes were prepared with a laboratory-prepared high-purity anti-Er.A-mAb. The effects of pH, antibody titer, and antigen concentration (test line) on the test strip performance were investigated. The colloidal gold test strip prepared with 8 μL potassium carbonate addition, 4 µg/mL antibody, 1.0 mg/mL antigen (test line), and 3 μL gold-labeled antibody showed acceptable specificity and a low limit of detection. The test strip showed the detection limit of 25 ng/mL for enramycin A, with a linear range of 25-300 ng/mL. The experiments on the feed with positive sample addition proved that the test strip had good repeatability and was more sensitive than high-performance liquid chromatography, being applicable for the rapid detection of enramycin in large batches of feed samples.