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.

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.

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.

Green synthesis of carbon quantum dots and their environmental applications.

Green synthesis of scalable, high-quality, fluorescent carbon quantum dots (CQDs) from natural biomass remains attractive due to their outstanding environmental application. CQDs are an emerging class of zero-dimensional carbon nanomaterials (<10 nm) that have recently attracted much attention due to their strong optical properties, biocompatibility, nontoxicity, uniform particle size, high photostability, low-cost synthesis, and highly tunable photoluminescence. The unique properties of CQDs possess a broad range of prospective applications in a number of fields such as metal ions detection, photocatalysis, sensing, medical diagnosis, bioimaging, and drug delivery. CQD nanostructures are synthesized using various techniques such as hydrothermal method, laser ablation, microwave irradiation, electrochemical oxidation, reflux method, and ultrasonication. However, this type of fabrication approach requires several chemical reactions including oxidation, carbonization, and pyrolysis. Green synthesis of CQDs has several advantages such as the use of low-cost and non-toxic raw materials, renewable resources, simple operations, and being environment-friendly. This review article will discuss the physicochemical properties of CQDs techniques used in the production of CQDs, and the stability of CQDs along with their applications in wastewater treatment and biomedical fields.

Nucleic acid amplification-based microfluidic approaches for antimicrobial susceptibility testing.

Because of the global spread of antimicrobials, there is an urgent need to develop rapid and effective tools for antimicrobial susceptibility testing to help clinicians prescribe accurate and appropriate antibiotic doses sooner. The conventional methods for antimicrobial susceptibility testing are usually based on bacterial culture methods, which are time-consuming, complicated, and labor-intensive. Therefore, other approaches are needed to address these issues. Recently, microfluidic technology has gained significant attention in infection management due to its advantages including rapid detection, high sensitivity and specificity, highly automated assay, simplicity, low cost, and potential for point-of-care testing in low-resource areas. Microfluidic advances for antimicrobial susceptibility testing can be classified into phenotypic (usually culture-based) and genotypic tests. Genotypic antimicrobial susceptibility testing is the detection of resistant genes in a microorganism using methods such as nucleic acid amplification. This review (with 107 references) surveys the different forms of nucleic acid amplification-based microdevices used for genotypic antimicrobial susceptibility testing. The first section reviews the serious threat of antimicrobial-resistant microorganisms and the urgent need for fast check-ups. Next, several conventional antimicrobial susceptibility testing methods are discussed, and microfluidic technology as a promising candidate for rapid detection of antimicrobial-resistant microorganisms is briefly introduced. The next section highlights several advancements of microdevices, with an emphasis on their working principles and performance. The review concludes with the importance of fully integrated microdevices and a discussion on future perspectives.

Development of a highly sensitive sensor chip using optical diagnostic based on functionalized plasmonically active AuNPs.

Measuring solution concentration plays an important role in chemical, biochemical, clinical diagnosis, environmental monitoring, and biological analyses. In this work, we develop a transmission-mode localized surface plasmon resonance sensor chip system and convenient method which is highly efficient, highly sensitive for detection sensing using multimode fiber. The plasmonically active sensor's surface AuNPs with high-density NPs were decorated onto 1 cm sensing length of various clad-free fiber in the form of homogeneous monolayer utilizing a self-assembly process for immobilization of the target molecule. The carboxyl bond is formed through a functional reaction on the sensor head. Using the significance in the refractive index difference and numerical aperture, which is caused by a variation in the concentration of measuring bovine serum albumin (BSA) protein which can be accurately measured by the output signal. The refractive index variation of the medium analyte layer can be converted to signal output power change at the He-Ne wavelength of 632.8 nm. The sensor detection limit was estimated to be 0.075 ng ml-1for BSA protein which shows high sensitivity compared to other types of label-free optical biosensors. This also leads to a possibility of finding the improvement in the sensitivity label-free biosensors. The conventional method should allow multimode fiber biosensors to become a possible replacement for conventional biosensing techniques based on fluorescence.

Bimetallic Thin-Film Combination of Surface Plasmon Resonance-Based Optical Fiber Cladding with the Polarizing Homodyne Balanced Detection Method and Biomedical Assay Application.

In this work, we present the optical birefringence properties of the optical fiber cladding that exists as an evanescent field where the refractive index (RI) of the analysis solution is applied for optical sensor aspiration. To enhance the performance of the sensor, we have investigated the sensor with different thicknesses of TiO2 coating and bimetallic (Ag-Al) film alloy combinations by thermal evaporation coating. We described a special balanced homodyne detection method for the intensity difference change between the p- and s-polarization lights in the surface plasmon resonance sensing systems, which is strongly determined by the RI of the test medium. The plasmonic optical fiber can measure a very small change of the RI of a glycerol solution, which is a resolution of 4.37 × 10-8 RI unit (RIU). This method has great advantages of a small-sized optical setup, high stability, high selectivity, easy chemical modification, and low cost. Furthermore, because of the experiment results, we observe that our approach can also eliminate the surrounding noise in the Mach-Zehnder interferometer, which shows the feasibility of this proposed technique. We demonstrate the fluorescence enhancement in detecting the C-reactive protein antibody conjugated with fluorescein isothiocyanate by means of near-field coupling between surface plasmons and fluorophores at spectral channels of emission. This technique can also be extended for application in a biomedical assay and in biochemical science, including molecular diagnostics relying on multichannels that require a small volume of the analyte at each channel which would suffer from the weakness of fluorescence if it were not for the enhancement technology.

Chemically robust succinimide-group-assisted irreversible bonding of poly(dimethylsiloxane)-thermoplastic microfluidic devices at room temperature.

This study investigates surface chemical modification using anhydride silane and amino silane reagents at room temperature (RT) to realize bonding between silicon-based PDMS and non-silicon thermoplastics. The anhydride silane shows vigorous activity against water, forming a terminal dicarboxylic acid in the plasma-activated elastomeric poly(dimethylsiloxane) (PDMS) surface, and it can readily react with amino-silane-modified thermoplastic surfaces, resulting in a permanent bond via the formation of a stable succinimide group without the requirement for high temperature or additional pressure to initiate the bonding. The modified surfaces of PDMS and thermoplastics were successfully characterized by water contact angle measurement, fluorescence measurement, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The bond strength values of PDMS-thermoplastic assemblies, measured by the tensile test for PDMS-polystyrene (PS), PDMS-poly(methyl methacrylate) (PMMA), PDMS-polycarbonate (PC), and PDMS-poly(ethyl terephthalate) (PET) assemblies, were found to be approximately 519.5 ± 6, 259 ± 15, 476.6 ± 8, and 458.2 ± 27 kPa, respectively. Moreover, the bond strength was further examined by performing a burst test for PDMS-PMMA, PDMS-PS, PDMS-PC, and PDMS-PET microfluidic devices, which were found to have the maximum pressure values at approximately 344.73, 448.15, 413.68, and 379.21 kPa, respectively. Based on these results, the hybrid microfluidic devices can be used for high-pressure experiments such as blood plasma separation and continuous-flow polymerase chain reaction (CF-PCR). We have also performed the large area bonding of the PDMS-PC assembly (10 × 10 cm2), ensuring the high robustness and reliability of the proposed surface chemical bonding method.

Microfluidic device fabrication mediated by surface chemical bonding.

This review discusses various bonding strategies for fabricating microfluidic devices, with a special emphasis on the modification of the surface assisted by the use of chemicals to assemble microfluidic devices under mild conditions such as room temperature and atmospheric pressure. The paper includes an overview of the wide ranges of bonding methods used in the fabrication of microfluidic systems, such as anodic bonding, fusion bonding, thermal bonding, solvent bonding, and surface chemical bonding. Among these, surface chemical bonding plays a crucial role between the polydimethylsiloxane (PDMS) and thermoplastics in order to assemble a microfluidic device in a simple and facile manner. The first section reviews relevant research on the sealing for microfluidic devices; in the second section, the materials used for device fabrication are reviewed. The third section discusses the different sealing processes used in the fabrication of microfluidic devices on silicon, glass, thermoplastic, and elastomer. Overall, this review concludes with a discussion on the importance of the surface chemical modification for bonding an elastomer - PDMS - with rigid materials at room temperature under atmospheric pressure and detailed discussions on their bond strengths.

Paper-Based All-in-One Origami Microdevice for Nucleic Acid Amplification Testing for Rapid Colorimetric Identification of Live Cells for Point-of-Care Testing.

We report herein the colorimetric identification of live cells based on a nucleic acid amplification testing (NAAT) methodology using an all-in-one origami paper microdevice integrated with DNA purification, loop-mediated isothermal amplification (LAMP), and on-site colorimetric detection. First, origami paper was partially embossed to create microchannel networks and chambers. Subsequently, hydrophobic polydimethylsiloxane prepolymer was coated onto the embossed paper to stabilize the structures on paper and provide fluid barriers. The paper microdevice was composed of splitting, purification, wicking, reaction, and dye pads folded alternatively to accomplish sensitive and specific NAAT. For the viability assay, propidium monoazide (PMA) was employed to penetrate dead cells and form covalent bonds with necrotic cell DNA; thus, amplification can be solely performed with DNA obtained from live bacterial cells. Purification functionality was implemented into the microdevice using chitosan to electrostatically capture DNA. Herein, methylene blue, which is typically used for electrochemical detection, is introduced for the first time for colorimetric detection of LAMP amplicons. This origami paper microdevice was successfully applied to determine the viability of foodborne pathogens, such as Escherichia coli O157:H7 and Salmonella spp., in which amplification was performed for 30 min followed by the execution of the colorimetric method for 10 min, thereby demonstrating tremendous potential for multiplexing and versatility for point-of-care applications. The introduced origami paper microdevice could be an attractive substitute as an instantaneous and convenient screening tool for the identification of viable pathogens in the control and monitoring of foodborne outbreaks in low-resource environments.

Fabrication of a polycarbonate microdevice and boronic acid-mediated surface modification for on-chip sample purification and amplification of foodborne pathogens.

In this study, we integrated sample purification and genetic amplification in a seamless polycarbonate microdevice to facilitate foodborne pathogen detection. The sample purification process was realized based on the increased affinity of the boronic acid-modified surface toward the cis-diol group present on the bacterial outer membrane. The modification procedure was conducted at room temperature using disposable syringe. The visible color and fluorescence signals of alizarin red sodium were used to confirm the success of the surface modification process. Escherichia coli O157:H7 containing green fluorescence protein (GFP) and Staphylococcus aureus were chosen as the microbial models to demonstrate the nonspecific immobilization using the microdevice. Bacterial solutions of various concentrations were injected into the microdevice at three flow rates to optimize the operation conditions. This microdevice successfully amplified the 384-bp fragment of the eaeA gene of the captured E. coli O157:H7 within 1 h. Its detection limit for E. coli O157:H7 was determined to be 1 × 103 colony-forming units per milliliter (CFU mL-1). The proposed microdevice serves as a monolithic platform for facile and on-site identification of major foodborne pathogens.

Hybrid elastomer-plastic microfluidic device as a convenient model for mimicking the blood-brain barrier in vitro.

In this study, we fabricated a hybrid elastomer-plastic microdevice using the silicone elastomer poly(dimethylsiloxane) (PDMS) and the plastic polycarbonate (PC), to mimic the human blood-brain barrier (BBB) in vitro. Specifically, the microchannel-imprinted elastomer was first coated with 3-aminopropyltriethoxysilane to produce amine-terminated PDMS. Then, simply by conformal contact at room temperature, the amine-functionalized PDMS was bonded to pristine PC through the formation of urethane linkages. Aside from realizing device bonding, the amine functionalization also assisted in subsequent dopamine coating to form polydopamine and provide a stable surface for culturing human endothelial cells and central nervous system-related cells (e.g., astrocytes) inside the microchannels. Successful mimicking of the BBB-like microenvironment was assessed by 3D co-culturing of human endothelial cells and astrocytes, where the microdevice was verified as an acceptable in vitro BBB model according to the following four criteria: the formation of tight junctions at the cell-cell boundaries of the endothelial cells, evaluated by the expression of the tight junction marker ZO-1; the formation of actin filaments, evaluated using rhodamine phalloidin dye; low permeability, tested using the fluorescent tracer 40-kDa FITC-dextran; and good transendothelial electrical resistance (a measure of the tight junction integrity formed between the endothelial cells). The fabricated PDMS-PC microfluidic device ensured simple yet stable device sealing, and simultaneously enhanced BBB-mimicking cell attachment, thus fulfilling all major criteria for its application as a convenient in vitro BBB model.

Microdevice-based solid-phase polymerase chain reaction for rapid detection of pathogenic microorganisms.

We demonstrate the integration of DNA amplification and detection functionalities developed on a lab-on-a-chip microdevice utilizing solid-phase polymerase chain reaction (SP-PCR) for point-of-need (PON) DNA analyses. First, the polycarbonate microdevice was fabricated by thermal bonding  to contain microchambers as reservoirs for performing SP-PCR. Next, the microchambers were subsequently modified with polyethyleneimine and glutaraldehyde for immobilizing amine-modified forward primers. During SP-PCR, the immobilized forward primers and freely diffusing fluorescence-labeled reverse primers cooperated to generate target amplicons, which remained covalently attached to the microchambers for the fluorescence detection. The SP-PCR microdevice was used for the direct identifications of two widely detected foodborne pathogens, namely Salmonella spp. and Staphylococcus aureus, and an alga causing harmful algal blooms annually in South Korea, Cochlodinium polykrikoides. The SP-PCR microdevice would be versatilely applied in PON testing as a universal platform for the fast identification of foodborne pathogens and environmentally threatening biogenic targets.

Fabrication of 3D continuous-flow reverse-transcription polymerase chain reaction microdevice integrated with on-chip fluorescence detection for semi-quantitative assessment of gene expression.

We fabricate a three-dimensional (3D) microdevice operated with minimal peripheral accessories, including a portable pump for semi-automated sample delivery and a single heater for temperature control, for performing reverse transcription polymerase chain reaction (RT-PCR) integrated with a downstream fluorescence detection module for semi-quantitative assessment of gene expression. The microdevice was fabricated by wrapping a polytetrafluoroethylene (PTFE) tube around a pre-designed polycarbonate mold to create a seamless microchannel for both the reverse transcription (RT) of RNA and the amplification of complementary DNA. In addition, a silicone tube, which underwent a two-step surface modification mediated by polyethyleneimine and glutaraldehyde coating, was connected at the outlet to capture amplicons downstream of the PTFE tube for on-site fluorescence detection. This fabrication method enabled continuous-flow RT-PCR (CF RT-PCR) using the 3D CF RT-PCR microdevice as a reactor, a single heater for the temperature control of both RT and PCR processes, and a disposable plastic syringe for semi-automated sample delivery. The microdevice was successfully implemented for the identification of the ß-actin gene, a constitutively expressed gene in all cells, and the sphingosine-1-phosphate lyase 1 gene, a potential pharmacological target gene in the diagnosis of cancer, diabetes, and atherosclerosis. This portable integrated microdevice offers a potential approach towards preliminary studies of gene expression and identification of RNA viruses.

A review on microscale polymerase chain reaction based methods in molecular diagnosis, and future prospects for the fabrication of fully integrated portable biomedical devices.

Since the advent of microfabrication technology and soft lithography, the lab-on-a-chip concept has emerged as a state-of-the-art miniaturized tool for conducting the multiple functions associated with micro total analyses of nucleic acids, in series, in a seamless manner with a miniscule volume of sample. The enhanced surface-to-volume ratio inside a microchannel enables fast reactions owing to increased heat dissipation, allowing rapid amplification. For this reason, PCR has been one of the first applications to be miniaturized in a portable format. However, the nature of the basic working principle for microscale PCR, such as the complicated temperature controls and use of a thermal cycler, has hindered its total integration with other components into a micro total analyses systems (µTAS). This review (with 179 references) surveys the diverse forms of PCR microdevices constructed on the basis of different working principles and evaluates their performances. The first two main sections cover the state-of-the-art in chamber-type PCR microdevices and in continuous-flow PCR microdevices. Methods are then discussed that lead to microdevices with upstream sample purification and downstream detection schemes, with a particular focus on rapid on-site detection of foodborne pathogens. Next, the potential for miniaturizing and automating heaters and pumps is examined. The review concludes with sections on aspects of complete functional integration in conjunction with nanomaterial based sensing, a discussion on future prospects, and with conclusions. Graphical abstract In recent years, thermocycler-based PCR systems have been miniaturized to palm-sized, disposable polymer platforms. In addition, operational accessories such as heaters and mechanical pumps have been simplified to realize semi-automatted stand-alone portable biomedical diagnostic microdevices that are directly applicable in the field. This review summarizes the progress made and the current state of this field.

An integrated microfluidic PCR system with immunomagnetic nanoparticles for the detection of bacterial pathogens.

There is growing interest in rapid microbial pre-concentration methods to lower the detection limit of bacterial pathogens of low abundance in samples. Here, we report an integrated microfluidic PCR system that enables bacterial cells of interest in samples to be concentrated prior to PCR. It consists of two major compartments: a preconcentration chamber for the immunomagnetic separation of bacterial cells, and a PCR chamber for the DNA amplification of the concentrated cells. We demonstrate the feasibility of the system for the detection of microbial pathogens by preconcentrating the human pathogen Escherichia coli O157:H7, and also amplifying its DNA. The detection limit of E. coli O157:H7 in the PCR system is 1 × 103 CFU (colony forming unit)/mL. On-chip processing steps, including preconcentration and PCR steps, take less than two hours. Our system can serve as a rapid, specific, and quantitative platform for the detection of microbial pathogens in samples of large volume.

A functionally integrated thermoplastic microdevice for one-step solid-phase-based nucleic acid purification and isothermal amplification for facile detection of foodborne pathogen.

In this study, we fabricate a functionally integrated monolithic thermoplastic microdevice for continuous operation of nucleic acid purification and amplification using polycarbonate (PC). A solid-phase-based purification and subsequent isothermal amplification, specifically, thermal helicase-dependent amplification (tHDA), was performed in a single operation in a valve-free manner. PC microdevice was assembled using modified thermal bonding process under relatively low temperature and pressure condition, realized by surface chemical modification of PC into hydrophilic property using amine-bearing polyethyleneimine (PEI). After the device sealing, only the microchannel parts were selectively modified to be hydrophobic, using epoxy-terminated poly(dimethylsiloxane) (PDMS) (epoxy-PDMS) on amine-coated surface for stepwise introduction of multiple reagents in a valve-free manner. Using the integrated PC microdevice, nucleic acids from genetically modified Escherichia coli (E. coli) O157:H7 were captured inside a chamber bearing amine functionality, by electrostatic interaction, and were subsequently amplified isothermally in the same chamber. Purified DNA captured inside the microchamber was detected directly inside the chamber by fluorescence measurement, and a 92-bp long EaeA gene, inserted into the E. coli O157:H7, was successfully amplified using the integrated PC microdevice in less than 90 min, paving the way for facile identification of foodborne pathogens with simple operation and reduced peripheral operations applicable for portable healthcare purposes. Biotechnol. Bioeng. 2016;113: 2614-2623. © 2016 Wiley Periodicals, Inc.

Flow-through polymerase chain reaction inside a seamless 3D helical microreactor fabricated utilizing a silicone tube and a paraffin mold.

We introduce a new strategy for fabricating a seamless three-dimensional (3D) helical microreactor utilizing a silicone tube and a paraffin mold. With this method, various shapes and sizes of 3D helical microreactors were fabricated, and a complicated and laborious photolithographic process, or 3D printing, was eliminated. With dramatically enhanced portability at a significantly reduced fabrication cost, such a device can be considered to be the simplest microreactor, developed to date, for performing the flow-through polymerase chain reaction (PCR).

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.