Paper-based Analytical Devices Research Articles

Development and Evaluation of a Noninvasive Microfluidic-Based Paper Analytical Device for Leptospirosis Diagnosis.

Leptospirosis is a re-emerging infectious disease that presents a diagnostic enigma for clinicians with frequent misdiagnosis due to lack of rapid and accurate diagnostic tests, as the current methods are encumbered by inherent limitations. The development of a diagnostic sensor with a sample-in-result-out capability is pivotal for prompt diagnosis. Herein, we developed a microfluidic paper-based analytical device (spin-μPAD) featuring a sample-in-result-out fashion for the detection of Leptospira specific urinary biomarker, sph2 sphingomyelinase, crucial for noninvasive point-of-care testing. Fabrication of paper devices involved precise photolithography techniques, ensuring a high degree of reproducibility and replicability. By optimizing the device's configuration and protein components, a remarkable sensitivity and specificity was achieved for detecting leptospiral sph2 in urine, even at low concentrations down to 1.5 fg/mL, with an assay time of 15 min. Further, the spin-μPAD was validated with 20 clinical samples, suspected of leptospirosis including other febrile illnesses, and compared with gold standard microscopic agglutination test, culture, Lepto IgM ELISA, darkfield microscopy, and Leptocheck WB spot test. In contrast to commercial diagnostic tools, the spin-μPAD was noninvasive, rapid, easy to use, specific, sensitive, and cost-effective. The results highlight the potential of this innovative spin-μPAD for an efficient and dependable approach to noninvasive leptospirosis diagnosis, addressing critical needs in the realms of public health and clinical settings.

Custom-printed microfluidic chips using simultaneous ratiometric fluorescence with "Green" carbon dots for detection of multiple antibiotic residues in pork and water samples.

In the evolving field of food safety, rapid and precise detection of antibiotic residues is crucial. This study aimed to tackle this challenge by integrating advanced inkjet printing technology with sophisticated microfluidic paper-based analytical devices (µPADs). The µPAD design utilized "green" quantum dots synthesized via an eco-friendly hydrothermal method using green white mulberry leaves as the carbon source, serving as the key fluorescent detection material. The action mechanism involved a photoinduced electron transfer system using red carbon dots (CDs) as electron donors and blue CDs combined with two-dimensional layered molybdenum disulfide (MoS2) nanosheets as electron acceptors. This system could quickly detect antibiotics within 10min in pork and water samples, demonstrating high sensitivity and recovery rates: 6.5pmol/L at 99.75%-110% for sulfadimethoxine, 3.3pmol/L at 99%-105% for sulfamethoxazole, and 8.5pmol/L at 98.5%-105% for tetracycline. It achieved a relative standard deviation under 5%, ensuring reliability and reproducibility. The fabricated sensor offered a promising application for the rapid and efficient on-site detection of antibiotic residues in food.

EGaIn-Modified ePADs for Simultaneous Detection of Homocysteine and C-Reactive Protein in Saliva toward Early Diagnosis of Cardiovascular Disease.

Homocysteine (Hcy) and C-reactive protein (CRP) are critical biomarkers for numerous chronic diseases, with cardiovascular disease (CVD) being the most prevalent. The ability to simultaneously detect both biomarkers in point-of-care settings is in high demand for CVD early diagnosis and prevention. Herein, we prepared the eutectic gallium indium (EGaIn) nanoparticles decorated with p-phenylenediamine (PPD) on the surface to facilitate the subsequent attachment of gold nanoparticles (AuNPs) to achieve EGaIn-PPD@Au, which was modified on the screen-printed electrochemical paper-based analytical devices (ePADs). Aptamers that are specific to Hcy and CRP were then immobilized on the EGaIn-PPD@Au surface to achieve the sensing interface on ePADs. The presence of EGaIn-PPD@Au significantly enhanced the electrical conductivity, leading to amplified electrochemical signals. This aptasensor demonstrated high specificity, capable of detecting Hcy in a range of 1-50 μM with a detection limit of 0.22 μM, and the detection range for CRP was 1-100 ng/mL with a detection limit of 0.039 ng/mL. The aptasensor also effectively detected Hcy and CRP in clinical saliva samples, yielding an area under the curve (AUC) of about 0.80 when the individual biomarker was considered and 0.93 when both biomarkers were taken into account. The positive correlation observed between salivary and blood concentrations of Hcy and CRP, coupled with their association with cardiovascular disease (CVD), suggested the potential of this methodology as a noninvasive point-of-care strategy for the early diagnosis of CVD.

Low-cost precision agriculture for sustainable farming using paper-based analytical devices.

The United Nations estimates that by 2030, agricultural production must increase by 70% to meet food demand. Precision agriculture (PA) optimizes production through efficient resource use, with soil fertility being crucial for nutrient supply. Traditional nutrient quantification methods are costly and time-consuming. This study introduces a rapid (15 min), user-friendly, paper-based platform for determining four essential macronutrients-nitrate, magnesium, calcium, and ammonium-using colorimetric methods and a smartphone for data reading and storage. The sensor effectively detects typical soil nutrient concentrations, showing strong linearity and adequate detection limits. For nitrate, the RGB method resulted in an R 2 of 0.992, a detection range of 0.5 to 10.0 mmol L-1, and an LOD of 0.299 mmol L-1. Calcium quantification using grayscale displayed an R 2 of 0.993, a detection range of 2.0 to 6.0 mmol L-1, and an LOD of 0.595 mmol L-1. Magnesium was best quantified using the hue color space, with an R 2 of 0.999, a detection range of 1.0 to 6.0 mmol L-1, and an LOD of 0.144 mmol L-1. Similarly, ammonium detection using the hue color space had an R 2 of 0.988, a range of 0.5 to 2.5 mmol L-1, and an LOD of 0.170 mmol L-1. This device enhances soil fertility assessment accessibility, supporting PA implementation and higher food production.

A novel indicator for lead poisoning beyond blood lead level: Facile diagnosis of lead poisoning using random urine with point-of-care testing

Lead (Pb) poisoning is estimated to account for 1 % of the global disease burden. The gold standard for diagnosing lead poisoning in human body relies on blood lead level (BLL), which is always performed in hospitals using expensive instruments. However, there are still many countries and regions with a lack of medical resources (without enough professional medical staff and analytical instruments). To achieve a facile diagnosis of lead poisoning by ordinary residents (without any expertise), this study conducted a research study on 810 participants to discover and validate a new lead poisoning indicator (creatinine-corrected urinary lead level, cULL) beyond BLL in non-invasive samples. A point-of-care testing (POCT) device to measure cULL was developed, equipped with liquid-phase microextraction and electromembrane extraction on a paper-based analytical device for on-site separation of lead and creatinine in the urine, using a smartphone for the quantification of analytes. The cULL as a novel indicator and the POCT device developed could be effective in reducing the risk of damage from lead contamination.

Unveiling the effect of paper matrix on the electrochemical response of diffusive redox probes

This study evaluates the influence of paper substrate selection on the electrochemical response of an electrochemical paper-based analytical device (ePAD). Various paper substrates commonly employed in this type of devices such as cellulose, nitrocellulose and glass-fibre based medical grade materials are evaluated using chronoamperometric measurements. Both theoretical modelling and experimental analyses are conducted to understand the diffusion behaviour of widely employed two redox probes, [Fe(CN)6]3− and FcMeOH. Findings show that glass fibre substrates show similar performance to liquid drop conditions while nitrocellulose cause a decrease in current after a short measurement period, mainly due to a thin-layer effect. Cellulose-based substrates decrease the diffusivity of redox species, especially for charged species, indicating potential limitations in their use for chronoamperometric measurements. The study offers valuable insights into the electrochemical behaviour of paper substrates in ePADs, laying the groundwork for future research in this area.

A Programmable Microfluidic Paper-Based Analytical Device for Simultaneous Colorimetric and Photothermal Visual Sensing of Multiple Enzyme Activities.

New strategies for the simultaneous and portable detection of multiple enzyme activities are highly desirable for clinical diagnosis and home care. However, the methods developed thus far generally suffer from high costs, cumbersome procedures, and heavy reliance on large-scale instruments. To satisfy the actual requirements of rapid, accurate, and on-site detection of multiple enzyme activities, we report herein a smartphone-assisted programmable microfluidic paper-based analytical device (μPAD) that utilizes colorimetric and photothermal signals for simultaneous, accurate, and visual quantitative detection of alkaline phosphatase (ALP) and butyrylcholinesterase (BChE). Specifically, the operation of this μPAD sensing platform is based on two sequential steps. Cobalt-doped mesoporous cerium oxide (Co-m-CeO2) with remarkable peroxidase-like activities under neutral conditions first catalytically decomposes H2O2 for effectively converting colorless 3,3',5,5'-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB). The subsequent addition of ALP or BChE to their respective substrates produces a reducing substance that can somewhat inhibit the oxTMB transformation for compromised colorimetric and photothermal signals of oxTMB. Notably, these two-step bioenzyme-nanozyme cascade reactions strongly support the straightforward and excellent processability of this platform, which exhibit lower detection limits for ALP and BChE with a detection limit for BChE an order of magnitude lower than those of the other reported paper-based detection methods. The practicability and efficiency of this platform are further demonstrated through the analysis of clinical serum samples. This innovative platform exhibits great potential as a facile yet robust approach for simultaneous, accurate, and on-site visual detection of multiple enzyme activities in authentic samples.

A portable smartphone detection of ctDNA using MnB2 nanozyme and paper-based analytical device

The development of point-of-care testing (POCT) for circulating tumor DNA (ctDNA) is meaningful for the non-invasive cancers screening and diagnosis, particularly in resource-limited settings. The microfluidic paper-based analytical device (μPAD) provides an ideal platform, its application in ctDNA assays remains underexplored. In this work, a multifunctional μPAD was manufactured, which can enhance the efficiency and reduce the cost of ctDNA sensing. Additionally, a smartphone-based application analysis was fabricated for convenient, portable detection and colorimetric signal readout. Moreover, the novel oxidase-like MnB2 nanozyme was introduced in the sandwiches sensing strategy, utilizing its catalytic properties to effectively generate a colorimetric signal. The use of MnB2 nanozyme in sensing application is relatively novel, and its catalytic performance and mechanism was thoroughly evaluated via experiment and density functional theory (DFT) calculations. After optimizing the detection conditions, the proposed biosensor exhibited satisfactory results. Furthermore, the method was successfully used to detect ctDNA in tumor cell lysates and peripheral blood samples from tumor-bearing mice. The results were consistent with standard qPCR method, affirming the reliability of our POCT analysis device in ctDNA detection. Thus, this work not only provides a paper-based POCT device and intelligent analysis tool for portable cancers diagnosis, but it also paves a new application path for MnB2 nanozyme in the sensing filed.

Spontaneous aggregation-enhanced electrochemiluminescence via galvanic strategy

Researchers unremittingly strive to develop innovative luminophores to enhance intrinsic electrochemiluminescence (ECL) performance. However, the potential to harness facile strategies, such as manipulating the physical properties of luminophores while retaining functional chemical properties to fabricate cost-effective ECL complexes, remains underexplored. Herein, we reported a novel and efficient one-step galvanic technique to actualize aggregation-enhanced ECL (AEECL) of ruthenium complexes. It marked the first instance of the galvanic process being employed to synthesize aggregate luminophores through electrostatic attraction. The ECL intensity and efficiency of the prepared ruthenium complexes with AEECL properties surpassed traditional ruthenium complexes by 8.9 and 13.6 times, respectively, outperforming most reported luminophores. Remarkably, the target luminophore exhibited high stability across varied scan rates and temperatures. Furthermore, a binder-free and carbon paper-based AEECL analytical device for lidocaine detection was fabricated, achieving a satisfactory detection limit (0.34 nM) and selectivity. The convenient modulation strategy of aggregate structure, along with the transformative leap from insufficient ECL to AEECL, bring forth a new revenue in aggregate science. This research also promises a universally applicable and versatile protocol for future biological analysis and bioimaging applications.

Aptasensor platform based on electrochemical Paper-Based analytical device for histamine detection

This paper outlines a simple, affordable, and highly flexible rapid prototyping technique for creating electrochemical paper-based analytical devices (ePADs). The craft cutter printer used for ePAD fabrication offers high flexibility and simplicity, eliminating the need for specialized equipment such as a wax printer by generating both electrode patterns and hydrophilic barriers. The ePAD was utilized to construct an aptasensor for the determination of histamine, which is essential for several physiological functions, including gastric secretion, narcolepsy, cell differentiation, cell growth, neurotransmission, and neuromodulation. Following the preparation of an ePAD with a unique design specific to this work, surface characterization was conducted using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A single-use aptasensor was created by immobilizing histamine-specific aptamer onto the working electrode surface of the ePAD. By optimizing all experimental parameters, histamine detection was successfully performed using the differential pulse voltammetry (DPV) technique. The reproducibility and selectivity of the aptasensor were examined, and its potential applicability to real samples was tested in an artificial saliva. These findings suggest that the ePAD-based aptasensor provides a cost-effective and reliable method for histamine detection, with potential applications in various bioanalytical contexts.

Origami-inspired microfluidic paper-based analytical device (μPAD) for microorganism detection

AbstractPathogenic microorganisms impose great risk especially in resource-limited settings due to inaccessibility of diagnostic tools and monitoring devices. This is mainly caused by current methods often being economically demanding and complex in practice; while these methods are sensitive and accurate, they rarely follow Point-of-care (POC) approaches, which is essential for rapid detection and intervention. Incorporating origami into paper-based analytical devices (μPAD) presents an innovative alternative, offering affordability, portability, and ease of disposal. Herein, a colorimetric origami μPAD that is suitable for use in POC applications was developed. The μPAD was fabricated via laser ablation utilizing PVDF and cellulose membranes. In order to develop the biosensor platform, fabrication parameters were optimized and hydrophilicity of PVDF membranes was improved using various solvents. The PVDF membranes were characterized through light microscopy imaging, protein adsorption assay and contact angle measurements. Then, optimization of the assay parameters was carried out in order to improve sensitivity and resolution of the μPAD, utilizing Box-Behnken experimental design. The responses generated by the origami μPAD in form of visible color development were then analyzed using image processing. After optimization is concluded, E. coli detection was carried out as a model system. Resulting calculations showed a limit of detection (LoD) of 2 CFU/mL and a dynamic working range up to 106 CFU/mL for E. coli. Overall, developed origami μPAD promises an economic advantage compared to conventional methods, and provides rapid and sensitive results without the requirement of expertise or complex equipment.

Portable Device with Nicking Enzyme Enhanced Special RCA on μPADs toward Sensitive Detection of High-Risk HPV Infection.

Development of an accurate, rapid, and cost-effective portable device is in high demand for point-of-care molecular diagnosis toward disease screening. Here we report a one-pot homogeneous isothermal assay that leverages nicking endonuclease and minimum secondary structured rolling circle amplification (N-MSSRCA) for fast and sensitive quantification of nucleic acids on distance microfluidic paper-based analytical devices (dμPAD) by a portable custom-made fluorescence detector. Human papillomavirus (HPV) oncogenic E7 mRNA as the biomarker for cervical cancer was used as the model analyte. N-MSSRCA integrates ligase for target recognition, the nicking enzyme for primer generation, and the dual function of the Phi29 DNA polymerase for both on- and off-loop amplification. The proposed method was capable of detecting 1 and 10 fM of the analyte using the microplate reader and portable detector with dμPAD, respectively, with ∼1 h assay time. A cohort study of 40 cervical swab samples shows N-MSSRCA reached positive and negative predictive values of 87.5% and 93.5% using the portable detector with dμPAD, compared to 91.67% and 100% using the microplate reader. N-MSSRCA demonstrates potential in early screening of high-risk HPV infection as a generic strategy to detect various nucleic acids in point-of-care scenarios.

Paper based analytical platforms: A matrix adaptable approach to drug testing

Paper-based analytical devices (PADs) are becoming increasingly popular for drug analysis in various matrices. These affordable, portable platforms come with a range of benefits, such as their user-friendly design, straightforward operation, and minimal need for sample preparation. This study evaluates the potential applications of PADs in drug testing with a particular emphasis on the adaptability of PADs in terms of their ability to handle various types of samples during the testing process. In this study, the design, manufacturing, and performance of PADs for drug detection, as well as the influence that different biological samples have on the performance of PAD performance were investigated. PADs are discussed in this paper, with respect to their applications in forensic sample analysis, point-of-care testing and illicit drug testing. The study demonstrates the flexibility of PADs as platforms for drug testing in varied matrices. The authors highlight the fact that PADs are inexpensive, portable, user-friendly, and need minimum sample preparation, which makes them effective instruments in a variety of situations, including research, law enforcement, and healthcare. On the whole, this paper highlights the versatility of PADs, emphasizing their role as adaptable platforms for drug testing within different matrices. Scientists and professionals can utilize these cutting-edge devices to improve the efficiency and accessibility of drug analysis.

Dual colorimetric/electrochemical sensor of carbaryl in fruits on microfluidic paper-based analytical device connected with smartphone readout

A dual colorimetric/electrochemical sensor integrated with a microfluidic paper-based analytical device (μPAD) is created for rapid and sensitive detection of cabaryl in fruit. For colorimetric sensor, quercetin modified silver nanoparticle (QCT-AgNPs) is synthesized via self-reduction, resulting in the color change from green to dark green in the presence of cabaryl, which can be readily observed via naked eyes. This colorimetric sensor provides a linear response of 5 – 50 μM quantified by Image J software. For electrochemistry, AgNPs/MXene nanocomposite electrode offers high electrocatalytic activity towards the detection of carbarly with a linear range of 0 – 60 µM and a detection limit of 0.01 µM. The limit of detection values obtained from this dual sensor are lower than a cut-off of carbaryl residue in food, which is 7 mg.kg−1 (35 µM) verifying the desired sensitivity of this platform. Ultimately, this dual sensor is successfully applied for on-site detection of carbaryl in the orange samples read out on the smartphone with satisfactory results.

Multiplexed colorimetric assay of antioxidants in wines with paper-based sensors fabricated by pen plotting

This work reports the development of low-cost and rapid multiplexed colorimetric assay of antioxidants (total phenolics, antioxidant capacity, flavonoids and anthocyanins) in wines at daisy-shaped fluidic paper-based analytical devices (PADs). The desired fluidic patterns were formed on paper by pen drawing and colorimetric reagents were immobilized at the 6 peripheral test zones. The sample was added at the central sample zone, migrated to the test zones and reacted with the immobilized reagents producing characteristic colors that were captured and analyzed. The paper-based approach was applied to the analysis of several wine samples and the results were statistically correlated to standard solution-based colorimetric assays, indicating that it could be reliably used for ranking wines according to their antioxidants content. In addition, the paper-based analytical methodology is simple, instrument-free, portable, cost-effective, rapid and environment friendly.

Mathematical processing of RGB data in microfluidic paper-based analytical devices

Microfluidic paper-based analytical devices often are combined with scanners as detectors. In this work, different scanning options offered by scanners: resolution, scanning mode, exposure to radiation, colour restoration, and saving format were tested. Moreover, different attempts to mathematical data treatment based on intensities of three channels—Red, Green and Blue, were studied. All measurements presented in this article were conducted for a model dye—bromothymol blue and a model analyte—zinc(II) ion (complexed with xylenol orange in a paper matrix). The article summarizes the scanning options and possibilities of mathematical calculations. Nevertheless, it is suggested that the best option is to use the prior prepared calculation file to paste obtained intensities and compare all presented in this article (and the most frequently used) equations to process intensities and decide which one should be used in the particular analysis.

An origami microfluidic paper device based on core-shell Cu@Cu2S@N-doped carbon hollow nanocubes

BackgroudThe global prevalence of diabetes mellitus, a serious chronic disease with fatal consequences for millions annually, is of utmost concern. The development of efficient and simple devices for monitoring glucose levels is of utmost significance in managing diabetes. The advancement of nanotechnology has resulted in the indispensable utilization of advanced nanomaterials in high-performance glucose sensors. Modulating the morphology and intricate composition of transition metals represents a viable approach to exploit their structure/function correlation, thereby achieving optimal electrocatalytic performance of the synthesized catalysts. ResultsHerein, a sensitive and rapid Cu-encapsulated Cu2S@nitrogen-doped carbon (Cu@Cu2S@N–C) hollow nanocubes-functionalized microfluidic paper-based analytical device (μ-PAD) was fabricated. Through a delicate sacrificial template/interface technique and thermal decomposition, inter-connected hollow networks were formed to boost the active sites, and the carbon shell was coated to protect Cu from being oxidation. For application, the constructed μ-PAD is used for glucose sensing utilizing an origami automated sample pretreatment system enabled by a simple application of strong alkaline solution on wax paper. Under optimal circumstances, the Cu@Cu2S@N–C electrochemical biosensor exhibits broad detection range of 2–7500 μM (R2 = 0.996) with low detection limit of 0.16 μM (S/N = 3) and high sensitivity of 1996 μA mM−1 cm−2. Additionally, the constructed μ-PAD also exhibited excellent selectivity, stability, and reproducibility. SignificanceBy rationally designing the double-shell hollow nanostructure and introducing Cu-encapsulated inner layer, the synthesized Cu@Cu2S@N–C hollow nanocubes show large specific surface area, short diffusion channels, and high stability. The proposed origami μ-PAD has been successfully applied to serum samples without any additional sample preparation steps for glucose determination, offering a new perspective for early nonenzymatic glucose diagnosis.

Green synthesis of MIL53(Al)-modified paper-based analytical device for efficient extraction of neonicotinoid insecticides from environmental water samples

BackgroundThere is a need to develop low-cost, reliable and portable devices to enhance the efficiency of microextraction techniques in complex samples. Metal-organic frameworks (MOFs) have proven to be promising sorbents due to their well-documented properties. However, their green preparation and combination with paper-based substrates have not been satisfactorily explored to fabricate sustainable sorptive phases. ResultsIn this work, the hybridization of a paper substrate (as a sustainable support) with MOFs (as a sorptive phase) was carried out by one-pot approach. Concretely, the selected MOF, MIL-53(Al), was in-situ growth onto the paper surface in aqueous solution without the need for high temperature or pressure, thereby aligning with the Green Analytical Chemistry principles. The optimized composite (MIL-53(Al)@cellulose paper) was characterized and evaluated as extraction sorbent for five neonicotinoids (NEOs) (thiamethoxam, clothianidin, imidacloprid, acetamiprid, and thiacloprid). Furthermore, its feasibility was demonstrated by isolating these pollutants from environmental water samples, followed their determination by HPLC coupled to diode array detection. The whole method showed satisfactory analytical performance with recoveries between 86 and 114 %, suitable precision (with RSD lower than 14 %), and limits of detection ranged from 1.0 to 1.6 μg L−1. Besides, the greenness of the method was assessed by application of different existing metrics. The developed extraction device was affordable (<0.08 €/device) and mechanical and chemically stable, being possible its reuse more than 11 cycles, thus demonstrating its suitability for rapid screening of pesticides in environmental samples. SignificanceThis report presents, for the first time, the green synthesis of MIL-53(Al)cellulose paper composite and its application as a sorptive phase for the extraction of NEOs from environmental water samples. We believe that the proposed strategy for fabricating these sustainable paper-based sorptive phases paves the way for further hybridizations with other MOFs or materials. Additionally, it opens up large possibilities for their application in extraction of pollutants or other hazardous compounds in aquatic environments.

Hybrid photo paper-based microfluidic device for colorimetric detection of iodine in salt

Microfluidic paper-based analytical devices (µPADs) have gained widespread use in various analytical applications because they are low-cost and suitable for onsite testing. The development of µPADs, including fabrication methods, new materials, and enhancement functionality is crucial to advance their practical application in analytical chemistry. In this study, we introduce a new hybrid paper-based analytical device, the hybrid photo paper-based microfluidic device (hPPMD), which combines a photo paper-based microfluidic device (PPMD) with a µPAD. We conducted a systematic study that detailed hPPMD’s characteristics, including surface properties and fluidic transportation. The hPPMD showed two fluidic transportation behaviors: continuous flow and discontinuous flow at the device junction, depending on the orientation of the device combination. Our hPPMD could increase fluidic flow approximately four times the speed when six layers of guided channels were added. The customized hPPMD was used for colorimetric detection of iodine in table salt, and then the result was quantitatively analyzed using a computer and smartphone with color analysis software. The detection zones of the hPPMD showed a flawless circular color signal. Under optimum conditions, the hPPMD was sensitive enough to detect iodine in salt solutions at various concentrations ranging from 1 to 100 ppm. The developed hPPMD should be a simple and low-cost analytical device for onsite qualitative analysis of the iodine and other chemical contaminants in food and the environment.

Enhanced electrochemical detection of chikungunya virus through aptasensor modification with origami paper-based ternary nanocomposite

Electrochemical sensors have drawn significant attention due to their crucial significance in the early detection of infectious illnesses, signifying their critical importance in diagnostic applications. This study’s proposed novel aptasensor exhibits a distinctive origami-based ePAD design, utilizing a unique silver-gold and zinc oxide (Ag-Au-ZnO) ternary nanocomposite for enhanced charge-transfer properties. Composite nanomaterials have a lower toxicity level, a higher signal enhancement capacity, increased sensitivity, improved conductivity, superior solubility, enhanced resolution capabilities, and a more straightforward functionalization process than individual nanomaterials. Employing paper, an economically advantageous substrate amenable to large-scale production with an origami-based ePAD is a critical enhancement of the sensor’s commendable attributes. Categorized as precision tools with an eco-conscious design, these sensors stand out for their streamlined manufacturing of environmentally sensitive substrates. This research capitalizes on the inherent foldability of paper to construct a three-dimensional multi-angular aptasensor, demonstrating cutting-edge specificity for chikungunya virus (CHIKV) detection. X- ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), UV–vis spectroscopy, and Fourier transmission infrared spectroscopy (FTIR) characterized the nanocomposites. This study also includes aptamers as outstanding and sensitive instruments for quick diagnostic applications. With the use of Cyclic Voltammetry (CV), the analytical response of the aptasensor was carefully evaluated. The study demonstrates a broad linear detection range spanning from 1 ng/ml to 10 µg/ml, with an impressively low limit of detection (LOD) at 1 ng/ml for the CHIKV antigen (CHIKV-Ag), underscoring the novelty and heightened sensitivity of this aptasensor design. Moreover, the aptasensor successfully detects CHIKV antigens in serum samples, and a long stability test demonstrates its practical utility and long-term stability for clinical applications. The proposed study concludes by introducing a novel origami-based paper-based analytical device (ePAD) as a promising tool for the quick, precise, and selective identification of the CHIKV antigen as well as its affordability, easy fabrication, and suitability of POCT testing makes an excellent diagnosing technique in resource-limited settings.