Comprehensive review on fluorescent carbon dots and their applications in nucleic acid detection, nucleolus targeted imaging and gene delivery.

Carbon dots (CDs), including carbon quantum dots, graphene quantum dots, carbon nanodots, and polymer dots, have gained significant attention due to their unique structural and fluorescence characteristics. This review provides a comprehensive overview of the classification, structural characteristics, and fluorescence properties of CDs, followed by an exploration of various fluorescence sensing mechanisms and their applications in gene detection, nucleolus imaging, and gene delivery. Furthermore, the functionalization of CDs with diverse surface ligand molecules, including dye molecules, nucleic acid probes, and metal derivatives, for sensitive nucleic acid detection is systematically examined. Fluorescence imaging of the cell nucleolus plays a vital role in examining intracellular processes and the dynamics of subcellular structures. By analyzing the mechanism of fluorescence and structure-function relationships inherent in CDs, the nucleolus targeting abilities of CDs in various cell lines have been discussed. Additionally, challenges such as the insufficient organelle specificity of CDs and the inconsistent mechanisms underlying nucleolus targeting have also been highlighted. The unique physical and chemical properties of CDs, particularly their strong affinity toward deoxyribonucleic acid (DNA), have spurred interest in gene delivery applications. The use of nuclear-targeting peptides, polymers, and ligands in conjunction with CDs for improved gene delivery applications have been systematically reviewed. Through a comprehensive analysis, the review aims to contribute to a deeper understanding of the potential and challenges associated with CDs in biomedical applications.

D-Glucose-Mediated Gold Nanoparticle Fabrication for Colorimetric Detection of Foodborne Pathogens.

Gold nanoparticle (AuNP) fabrication via the oxidation of D-glucose is applied for detecting two foodborne pathogens, Enterococcus faecium (E. faecium) and Staphylococcus aureus (S. aureus). D-glucose is used as a reducing agent due to its oxidation to gluconic acid by sodium hydroxide (NaOH), resulting in the formation of AuNPs. Based on this mechanism, we develop AuNP-based colorimetric detection in conjunction with loop-mediated isothermal amplification (LAMP) for accurately identifying the infectious bacteria. Here, Au+ ions bind to the base of double-stranded DNA. In the presence of D-glucose and NaOH, the LAMP amplicon-Au+ complex maintains its bound state at 65 °C for 10 min while it is reduced to AuNPs in a dispersed form, exhibiting a red color. We aimed to pre-mix D-glucose with LAMP reagents before amplification and induce successful colorimetry without inhibiting amplification to simplify the experimental process and decrease the reaction time. Therefore, the entire process, including LAMP and colorimetric detection, is accomplished in approximately 1 h. The limit of detection of E. faecium and S. aureus is confirmed using the introduced method as 101 CFU/mL and 100 fg/µL, respectively. We expect that colorimetric detection using D-glucose-mediated AuNP synthesis offers an application for simple and immediate molecular diagnosis.

Electrospun fibers modified with polydopamine for enhancing human mesenchymal stem cell culture.

In this study, we coated electrospun polycaprolactone (PCL) fibers with polydopamine (PDA) to modify their hydrophobicity and fabricated a matrix for culturing mesenchymal stem cells (MSCs). Additionally, we incorporated Arg-Gly-Asp (RGD) peptides into PDA to enhance MSCs culture performance on PCL fibers. PDA and RGD were successfully coated in one step by immersing the electrospun fibers in a coating solution, without requiring an additional surface activation process. The characteristics of functionalized PCL fibers were analyzed by scanning electron microscopy with energy-dispersive x-ray analysis, Fourier transform infrared spectroscopy, water contact angle measurement, and fluorescence measurements using a carboxylic-modified fluorescent microsphere. MSCs cultured on the modified PCL fibers demonstrated enhanced cell adhesion, proliferation, and osteogenic- and chondrogenic differentiation. This study provides insight into potential applications for scaffold fabrication in MSCs-based tissue engineering, wound dressing, implantation, and a deeper understanding of MSCs behaviorin vitro.

ß-Cyclodextrin-Stabilized Silver Nanoparticle Production Combined with Loop-Mediated Isothermal Amplification for the Visual Detection of Contagious Pathogens.

ß-cyclodextrin (ß-CD) is a water-soluble, non-toxic, biocompatible, and cage compound that contains six, seven, or eight α-(1-4)-attached D-glucopyranose residues. The hydroxyl group in the ß-CD is responsible for the reduction of metal ions as well as stabilizing the nanoparticles. In this study, we developed a colorimetric assay for identifying contagious pathogens such as SARS-CoV-2 and Enterococcus faecium (E. faecium) via in situ development of ß-CD-stabilized silver nanoparticles (AgNPs). In the process, the LAMP amplicons produced a complex with silver nitrate (LAMP amplicon-Ag+) which was reduced when heated at 65 °C for 5 min in the presence of ß-CD and developed a brown color. The limit of detection was determined to be approximately 101 CFU mL-1 and 10 fg µL-1 for E. faecium and SARS-CoV-2, respectively. Significantly, the colorimetric examination of contagious diseases was completed in less than 50 min, including the LAMP assay and detection process. Owing to the high sensitivity and rapid readout mechanism of the ß-CD-stabilized AgNP-based colorimetric assay, it is anticipated that the introduced method can be efficiently utilized as a versatile point-of-care testing (POCT) platform for molecular diagnostics in resource-limited areas.

Pipette-free field-deployable molecular diagnostic kit for bimodal visual detection of infectious RNA viruses.

Here, we developed a field-deployable molecular diagnostic kit for the detection of RNA viruses that operates in a pipette-free manner. The kit is composed of acrylic sticks, PCR tubes, and palm-sized three-dimensional(3D)-printed heaters operated by batteries. The kit performs RNA extraction, reverse transcriptase loop-mediated isothermal amplification (RT-LAMP), and visual detection in one kit. An acrylic stick was engraved with one shallow and one deep cylindrical chamber at each end for the insertion of an FTA card and ethidium homodimer-1 (EthD-1), respectively, to perform RNA extraction/purification and bimodal visual detection of the target amplicons. First, an intercalation of EthD-1 into the target DNA initially produces fluorescence upon UV illumination. Next, the addition of a strong oxidant, in this case sodium (meta) periodate (NaIO4 ), produces intense aggregates in the presence of EthD-1-intercalated DNA, realized by electrostatic interaction. In the absence of the target amplicon, no fluorescence or aggregates are observed. Using this kit, two major infectious viruses-severe fever with thrombocytopenia syndrome virus (SFTSV) and severe acute respiratory syndrome coronavirus (SARS-CoV-2)-were successfully detected in 1 h, and the limits of detection (LOD) were approximately 1 virus µL-1 for SFTSV and 103 copies µL-1 for SARS-CoV-2 RNA. The introduced kit is portable, end-user-friendly, and can be operated in a pipette-free manner, paving the way for simple and convenient virus detection in resource-limited settings.

Microfluidic advances in food safety control.

Food contamination is a global concern, particularly in developing countries. Two main types of food contaminants-chemical and biological-are common problems that threaten human health. Therefore, rapid and accurate detection methods are required to address the threat of food contamination. Conventional methods employed to detect these two types of food contaminants have several limitations, including high costs and long analysis time. Alternatively, microfluidic technology, which allows for simple, rapid, and on-site testing, can enable us to control food safety in a timely, cost-effective, simple, and accurate manner. This review summarizes advances in microfluidic approaches to detect contaminants in food. Different detection methods have been applied to microfluidic platforms to identify two main types of contaminants: chemical and biological. For chemical contaminant control, the application of microfluidic approaches for detecting heavy metals, pesticides, antibiotic residues, and other contaminants in food samples is reviewed. Different methods including enzymatic, chemical-based, immunoassay-based, molecular-based, and electrochemical methods for chemical contaminant detection are discussed based on their working principle, the integration in microfluidic platforms, advantages, and limitations. Microfluidic approaches for foodborne pathogen detection, from sample preparation to final detection, are reviewed to identify foodborne pathogens. Common methods for foodborne pathogens screening, namely immunoassay, nucleic acid amplification methods, and other methods are listed and discussed; highlighted examples of recent studies are also reviewed. Challenges and future trends that could be employed in microfluidic design and fabrication process to address the existing limitations for food safety control are also covered. Microfluidic technology is a promising tool for food safety control with high efficiency and applicability. Miniaturization, portability, low cost, and samples and reagents saving make microfluidic devices an ideal choice for on-site detection, especially in low-resource areas. Despite many advantages of microfluidic technology, the wide manufacturing of microfluidic devices still demands intensive studies to be conducted for user-friendly and accurate food safety control. Introduction of recent advances of microfluidic devices will build a comprehensive understanding of the technology and offer comparative analysis for future studies and on-site application.

A paper-embedded thermoplastic microdevice integrating additive-enhanced allele-specific amplification and silver nanoparticle-based colorimetric detection for point-of-care testing.

This study introduces a thermoplastic microdevice integrated with additive-enhanced allele-specific amplification and hydrazine-induced silver nanoparticle-based detection of single nucleotide polymorphism (SNP) and opportunistic pathogens. For point-of-care testing of SNP, an allele-specific loop-mediated isothermal amplification reaction using nucleotide-mismatched primers and molecular additives was evaluated to discriminate single-nucleotide differences in the samples. The microdevice consists of purification and reaction units that enable DNA purification, amplification, and detection in a sequential manner. The purification unit enables the silica-based preparation of samples using an embedded glass fiber membrane. Hydrazine-induced silver nanoparticle formation was employed for endpoint colorimetric detection of amplicons within three min at room temperature. The versatile applicability of the microdevice was demonstrated by the successful identification of SNPs related to sickle cell anemia, genetically-induced hair loss, and Enterococcus faecium. The microdevice exhibited a detection limit of 103 copies per µL of SNP targets in serum and 102 CFU mL-1 of Enterococcus faecium in tap water within 70 min. The proposed microdevice is a promising and versatile platform for point-of-care nucleic acid testing of different samples in low-resource settings.

A point-of-care platform for hair loss-related single nucleotide polymorphism genotyping.

Rapid genotyping of single nucleotide polymorphism (SNP) is crucial for prognostics and disease management, enabling more rapid therapy selection and treatment determination. Here, we introduce a point-of-care platform for hair loss-related SNP genotyping based on allele-specific loop-mediated isothermal amplification (AS-LAMP) combined with naked-eye visualization. The specificity of the AS-LAMP assay was significantly enhanced by using mismatched allele-specific primers. AS-LAMP reaction and Schiff's reagent-based colorimetric detection were successfully performed using a thermoplastic genotyping chip. This strategy also showed potential for determining homozygotes and heterozygotes in a target sample. To assess SNP genotyping capacity, the genotyping chip was fabricated to visually detect rs6152 polymorphism of an androgen receptor gene associated with genetically induced hair loss. The genotyping platform rapidly identified the SNP within 40 min, and the detection limit was as low as 1 pg/µL of the target DNA contained in human serum. The introduced strategy showed high specificity and stability in discriminating low-abundance mutations, making it suitable as a portable and affordable point-of-care platform for rapid and accurate SNP discrimination applicable for bedside detection.

Pipette-Free and Fully Integrated Paper Device Employing DNA Extraction, Isothermal Amplification, and Carmoisine-Based Colorimetric Detection for Determining Infectious Pathogens.

A pipette-free and fully integrated device that can be used to accurately recognize the presence of infectious pathogens is an important and useful tool in point-of-care testing, particularly when aiming to decrease the unpredictable threats posed by disease outbreak. In this study, a paper device is developed to integrate the three main processes required for detecting infectious pathogens, including DNA extraction, loop-mediated isothermal amplification (LAMP), and detection. All key reagents, including sodium dodecyl sulfate (SDS), NaOH, LAMP reagents, and carmoisine, are placed on the paper device. The paper device is operated simply via sliding and folding without using any bulky equipment, and the results can be directly observed by the naked eye. The optimized concentrations of sodium dodecyl sulfate (SDS), sodium hydroxide (NaOH), and carmoisine were found to be 0.1%, 0.1 M, and 0.5 mg/mL, respectively. The paper device was used to detect Enterococcus faecium at concentrations as low as 102 CFU/mL within 60 min. Also, E. faecium spiked in milk was successfully detected using the paper device, demonstrating the feasible application in real sample analysis.

Carbon-dot-triggered aggregation/dispersion of gold nanoparticles for colorimetric detection of nucleic acids and its application in visualization of loop-mediated isothermal amplification.

In this study, cationic carbon dots (CDs) were prepared from p-phenylenediamine (pPDA) via a one-step hydrothermal method and used to trigger the aggregation and dispersion of gold nanoparticles (AuNPs) for the colorimetric detection of nucleic acids. Physicochemical characterization results revealed that the CDs are enriched with positively charged surface functional groups with an average size of ∼11 nm. The interaction between the CDs and AuNPs was confirmed via fluorescence and absorption studies. Absorption spectroscopic results revealed that the primary surface plasmon resonance (SPR) band of the AuNPs decreased upon introduction of CDs, and a new band emerged at ∼600 nm, indicating the aggregated assembly of AuNPs. Upon the introduction of double-stranded deoxyribonucleic acid (DNA), the band corresponding to the aggregated AuNPs showed a continuous decrease, accompanied by a simultaneous increase in the primary SPR band, leading to a noticeable purple-to-red color transformation. Based on this phenomenon, a colorimetric assay for DNA was developed, which relies on the interaction between negatively charged DNA and cationic CDs, leaving the AuNPs dispersed. The assay exhibited a linear response within a DNA concentration range of 0.7-14 nM with a detection limit of 1.70 nM. Selectivity results showed that colorimetric assays are specific for both DNA and single-stranded DNA (ssDNA). Smartphone-assisted detection was developed by monitoring the colorimetric response of a AuNPs/CDs probe. As a proof-of-concept experiment, the AuNPs/CDs probe was used to visualize the loop-mediated isothermal amplification (LAMP) of Escherichia coli (E. coli), a robust indicator of sewage contamination in water.

Chitosan: a green adhesive for surface functionalization and fabrication of thermoplastic biomedical microdevices.

Chitosan (CS) is a natural polymer that exhibits many biological properties and is used as a biomaterial for antibacterial coatings, tissue engineering, cell research, drug delivery, and negatively charged molecule capture. In our previous study, we used a CS-polydopamine mixture to realize UV-assisted bonding between poly(methyl methacrylate) (PMMA) substrates to fabricate microdevices for self-assembled stem cell spheroid cultures. Herein, we attained reliable adhesive bonding between PMMAs using CS at room temperature assisted by oxygen plasma. The bond strength of adhesion was as high as 2.1 MPa, which could be stable for over two months according to the leak test. The adhesive bonding and surface functionalization of the microchannels were simultaneously completed such that the microdevices could be directly used for mesenchymal stem cell culture for spheroid generation and DNA purification for point-of-care testing (POCT) devices. Surface characterization was performed by contact angle measurements, Fourier-transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. The POCT device allows sequential on-chip DNA purification, amplification, and colorimetric detection of pathogenic bacteria. This method provides a convenient and reliable strategy for the fabrication of PMMA microdevices that can be directly implemented in biological studies and POCT applications without involving prior surface modification steps.

Droplet-Based Microfluidics: Applications in Pharmaceuticals.

Droplet-based microfluidics offer great opportunities for applications in various fields, such as diagnostics, food sciences, and drug discovery. A droplet provides an isolated environment for performing a single reaction within a microscale-volume sample, allowing for a fast reaction with a high sensitivity, high throughput, and low risk of cross-contamination. Owing to several remarkable features, droplet-based microfluidic techniques have been intensively studied. In this review, we discuss the impact of droplet microfluidics, particularly focusing on drug screening and development. In addition, we surveyed various methods of device fabrication and droplet generation/manipulation. We further highlight some promising studies covering drug synthesis and delivery that were updated within the last 5 years. This review provides researchers with a quick guide that includes the most up-to-date and relevant information on the latest scientific findings on the development of droplet-based microfluidics in the pharmaceutical field.

Metagenomics: An Effective Approach for Exploring Microbial Diversity and Functions.

Various fields have been identified in the "omics" era, such as genomics, proteomics, transcriptomics, metabolomics, phenomics, and metagenomics. Among these, metagenomics has enabled a significant increase in discoveries related to the microbial world. Newly discovered microbiomes in different ecologies provide meaningful information on the diversity and functions of microorganisms on the Earth. Therefore, the results of metagenomic studies have enabled new microbe-based applications in human health, agriculture, and the food industry, among others. This review summarizes the fundamental procedures on recent advances in bioinformatic tools. It also explores up-to-date applications of metagenomics in human health, food study, plant research, environmental sciences, and other fields. Finally, metagenomics is a powerful tool for studying the microbial world, and it still has numerous applications that are currently hidden and awaiting discovery. Therefore, this review also discusses the future perspectives of metagenomics.

Advances in deoxyribonucleic acid extraction techniques and point-of-care molecular diagnosis of foodborne pathogens.

A conventional molecular assay-based point-of-care (POC) diagnostic test involves three major stages: deoxyribonucleic acid (DNA) extraction, amplification, and amplicon detection. Among these steps, DNA extraction is costly and time-consuming. Nevertheless, it is a crucial step for the identification of sensitive and specific diseases. This review summarizes the advantages and disadvantages of DNA extraction methods over the past 10 years to effectively implement POC pathogen testing in the future. The first section briefly explains the necessity of DNA extraction and molecular assays for food pathogen detection. The second section extensively discusses DNA extraction based on liquid-liquid extraction, solid-phase extraction, and electrophoretic techniques. Molecular assay-based methods and a few commercially available POC devices for the detection of foodborne pathogens are detailed in the third and fourth sections. Finally, present challenges and future perspectives for the fabrication of integrated POC devices are highlighted.

Point-of-Care Testing of the MTF1 Osteoarthritis Biomarker Using Phenolphthalein-Soaked Swabs.

Osteoarthritis (OA) is the most common joint disease, which accompanies pain and inconvenience in daily life owing to degradation of cartilage and adjacent tissues. In this study, we propose a simple point-of-care testing (POCT) kit for the detection of the MTF1 OA biomarker to achieve on-site clinical diagnosis of OA. The kit contains an FTA card for patient sample treatments, a sample tube for loop-mediated isothermal amplification (LAMP), and a phenolphthalein-soaked swab for naked eye detection. The MTF1 gene was isolated from synovial fluids using an FTA card and amplified using the LAMP method at 65 °C for 35 min. A test part of the phenolphthalein-soaked swab was decolorized in the presence of the MTF1 gene due to the pH change after the LAMP, but the color remained pink in the absence of the MTF1 gene. The control part of the swab served as a reference color in relation to the test part. When real-time LAMP (RT-LAMP), gel electrophoresis, and colorimetric detection of the MTF1 gene were performed, the limit of detection (LOD) was confirmed at 10 fg/µL, and the overall processes were completed in 1 h. The detection of an OA biomarker in the form of POCT was reported for the first time in this study. The introduced method is expected to serve as a POCT platform directly applicable by clinicians for easy and rapid identification of OA.

Recent Advances in Molecular and Immunological Diagnostic Platform for Virus Detection: A Review.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused an ongoing coronavirus disease (COVID-19) outbreak and a rising demand for the development of accurate, timely, and cost-effective diagnostic tests for SARS-CoV-2 as well as other viral infections in general. Currently, traditional virus screening methods such as plate culturing and real-time PCR are considered the gold standard with accurate and sensitive results. However, these methods still require sophisticated equipment, trained personnel, and a long analysis time. Alternatively, with the integration of microfluidic and biosensor technologies, microfluidic-based biosensors offer the ability to perform sample preparation and simultaneous detection of many analyses in one platform. High sensitivity, accuracy, portability, low cost, high throughput, and real-time detection can be achieved using a single platform. This review presents recent advances in microfluidic-based biosensors from many works to demonstrate the advantages of merging the two technologies for sensing viruses. Different platforms for virus detection are classified into two main sections: immunoassays and molecular assays. Moreover, available commercial sensing tests are analyzed.

Design Strategy and Application of Deep Eutectic Solvents for Green Synthesis of Nanomaterials.

The first report of deep eutectic solvents (DESs) was released in 2003 and was identified as a new member of ionic liquid (IL), involving innovative chemical and physical characteristics. Using green solvent technology concerning economical, practical, and environmental aspects, DESs open the window for sustainable development of nanomaterial fabrication. The DESs assist in different fabrication processes and design nanostructures with specific morphology and properties by tunable reaction conditions. Using DESs in synthesis reactions can reduce the required high temperature and pressure conditions for decreasing energy consumption and the risk of environmental contamination. This review paper provides the recent applications and advances in the design strategy of DESs for the green synthesis of nanomaterials. The strategy and application of DESs in wet-chemical processes, nanosize reticular material fabrication, electrodeposition/electrochemical synthesis of nanostructures, electroless deposition, DESs based nano-catalytic and nanofluidic systems are discussed and highlighted in this review.

PDMS Micropatterns Coated with PDA and RGD Induce a Regulatory Macrophage-like Phenotype.

Regulatory macrophages (Mreg) are a special cell type that present a potential therapeutic strategy for various inflammatory diseases. In vitro, Mreg generation mainly takes 7-10 days of treatment with chemicals, including cytokines. In the present study, we established a new approach for Mreg generation using a three-dimensional (3D) micropatterned polydimethylsiloxane (PDMS) surface coated with a natural biopolymer adhesive polydopamine (PDA) and the common cell adhesion peptide motif arginylglycylaspartic acid (RGD). The 3D PDMS surfaces were fabricated by photolithography and soft lithography techniques and were subsequently coated with an RGD+PDA mixture to form a surface that facilitates cell adhesion. Human monocytes (THP-1 cells) were cultured on different types of 2D or 3D micropatterns for four days, and the cell morphology, elongation, and Mreg marker expression were assessed using microscopic and flow cytometric analyses. The cells grown on the PDA+RGD-coated 3D micropatterns (20-µm width/20-µm space) exhibited the most elongated morphology and strongest expression levels of Mreg markers, such as CD163, CD206, CD209, CD274, MER-TK, TREM2, and DHRS9. The present study demonstrated that PDA+RGD-coated 3D PDMS micropatterns successfully induced Mreg-like cells from THP-1 cells within four days without the use of cytokines, suggesting a time- and cost-effective method to generate Mreg-like cells in vitro.

Copper: DNA extraction and solid phase detection agent for all-in-one molecular diagnostic device coupled with isothermal amplification.

In this study, an all-in-one poly(methyl methacrylate) (PMMA) device integrating two novel techniques - DNA extraction employing a CuSO4/H2O2 system and DNA detection utilizing solid phase copper tape - coupled with loop-mediated isothermal amplification (LAMP) is developed for on-site pathogen detection. The CuSO4/H2O2 system, also known as Fenton-like reaction, is used to produce hydroxyl radicals, which can disrupt bacterial membranes via lipid peroxidation and release DNA at room temperature. The released DNA is subsequently amplified by LAMP reaction. The acidic environment resulting from the production of hydrogen ions in the presence of target DNA in the LAMP reaction can stimulate the color change on copper tape due to the corrosion, while the innate alkaline environment in a negative sample not containing target DNA cannot stimulate the corrosion. The fabricated PMMA device integrates all the functionalities necessary for molecular diagnostics such as DNA extraction, amplification, and detection, and a carbon paste-based heater is fabricated for LAMP reaction. Using the PMMA device, Enterococcus faecium was detected as low as 4.67 × 102 CFU/mL within 90 min. E. faecium spiked in milk was successfully detected using the all-in-one PMMA device. The equipment-free techniques for decentralized diagnostics and naked-eye readout of results coupled with the portable heater serves as a promising solution for point-of-care testing particularly in a resource-limited environment.

Quercetin-Mediated Silver Nanoparticle Formation for the Colorimetric Detection of Infectious Pathogens Coupled with Loop-Mediated Isothermal Amplification.

Here, quercetin-mediated silver nanoparticle (AgNP) formation combined with loop-mediated isothermal amplification (LAMP) was introduced to colorimetrically detect two major infectious pathogens, SARS-CoV-2 and Enterococcus faecium, using a foldable PMMA microdevice. The nitrogenous bases of LAMP amplicons can readily form a complex with Ag+ ions, and the catechol moiety in quercetin, which acted as a reducing agent, could be chelated with Ag+ ions, resulting in the easy electron transfer from the oxidant to the reductant and producing brown-colored AgNPs within 5 min. The introduced method exhibited higher sensitivity than agarose gel electrophoresis due to more active redox centers in quercetin. The detection limit was attained at 101 copies µL-1 and 101 CFU mL-1 for SARS-CoV-2 RNA and E. faecium, respectively. A foldable microdevice made of two pieces of PMMA that fully integrates DNA extraction, amplification, and detection processes was fabricated to establish practical applicability. On one PMMA, DNA extraction was performed in a reaction chamber inserted with an FTA card, and then LAMP reagents were added for amplification. Silver nitrate was added to the reaction chamber after LAMP. On the other PMMA, quercetin-soaked paper discs loaded in the detection chamber were folded toward the reaction chamber for colorimetric detection. An intense brown color was produced within 5 min when heated at 65 °C. The introduced colorimetric assay, which is highly favorable for laboratory and on-site applications, could be a valuable alternative to conventional methods for detecting infectious diseases, given its unique principle, simplicity, and naked-eye detection.