Microfluidic Paper Research Articles

Lab‐on‐Paper Approach in lieu of Microfluidic Paper Assisted Platform: ‘ASSURED’ sensing through Modified Graphene Quantum Dots

AbstractMicrofluidic based sensors are one of the emerging alternatives for bringing solutions studies on paper platforms. Microfluidic paper assisted platform was developed over here through a simple, easy, cost effective and instrument free process. The self‐same method of waxing through crayoning, was estimated thoroughly on different paper platforms. Varied parameter including type of crayoning, way of patterning, color effect, wicking rate and channel optimization was performed on paper milieus. Optimized time of baking for obtaining controlled penetration ranges from 2 min to 8 min depending on the type of paper used. Wax crayoning was preferred over oil pasteling for making hydrophobic barriers uniformly, solid as well fully penetrated within paper inner layers. Fabrication through this easy cost‐effective route allows a formation of hydrophilic reaction or sensing zone of 0.25 cm2 with sufficient reactive area. Further sensing of dopamine on paper platform was carried using paper chip adsorbed with fluorescent modified graphene quantum dots as sensing material. The patterned paper showed advantage as only few microliter (5 μl to 10 μl) range of sample volume was required for testing. Fluorescence quenching with increase of concentration was witnessed where around 25–75 μM dopamine concentration was positively tested through naked eye; which for the first time was demonstrated here via robust wax crayoning method for developing paper based biosensor.

NASBA Coupled to Paper Microfluidics for RNA Detection.

The analysis of RNA sequences is crucial to obtain invaluable insights into disease prognosis. Reliable and rapid diagnostic solutions at the site of sample collection contribute toward optimal delivery of medical treatment. For this reason, the development of more sensitive and portable RNA detection techniques are expected to advance current point-of-care (POC) diagnostic capabilities. Advancements of POC diagnostic technologies will also contribute to counter the spread of emerging viruses. Reverse transcriptase polymerase chain reaction (RT-PCR) is the most commonly used technique to identify etiological organisms of infections. However, the need for thermocycler and fluorescent measurement renders RT-PCR less suitable for POC applications. Here, we provide a step-by-step protocol of Nucleic Acid Sequence-Based Amplification (NASBA), a robust isothermal RNA amplification technique, coupled with a portable paper microfluidics detection format.

NFC-enabled photothermal-based microfluidic paper analytical device for glucose detection.

This study introduces the development of a photothermal-based microfluidic paper analytical device (PT-µPAD) integrated with near-field communication (NFC) technology and smartphone readout for enzyme-free glucose quantification in human samples. With the properties of gold nanoparticles (AuNPs) both as a nanozyme and as a photothermal substrate, there is no need for costly reagents like enzymes or a readout instrumentation for the selective and sensitive detection of glucose. In PT-µPADs, AuNPs are etched by hydrogen peroxide (H2O2) generated from glucose catalysis. Photothermal detection from the plasmonic heating of these AuNPs when illuminated by a 533nm LED light source is achieved by inserting the PT-µPAD sensor into a portable NFC platform suitable for smartphone readout. Temperature variation is directly proportional to the glucose concentration. After optimization, we acquired a linear range between 5.0 and 20.0 µmol L-1 (R2 = 0.9967) and a limit of detection (LOD) of 25.0 nmol L-1 for glucose. Additionally, while our sensor does not utilize any enzyme, it is remarkably selective to glucose with no effects from interferences. Recovery studies in various human control samples indicated a range of 99.73-102.66% with the highest RSD of 3.53%, making it highly accurate and precise. Moreover, our method is more sensitive than other methods relying on conventional µPADs for glucose sensing. By integrating the potential benefits of microfluidics, nanomaterials as nanozymes, and NFC technology for wireless readout, our sensor demonstrates great promise as an accessible, affordable, and shelf-stable device for glucose quantification. Moreover, this concept can be extended to detect other molecules of interest as a point-of-care (POC) diagnostics device.

Detection of Covid-19 with Dual-Signal Probes in Paper Microfluidics

Current Covid-19 detection methods commercialized today that use colorimetric probes havethe advantage of short response time but the issue of low sensitivity. Other methods considerfluorescent probes that increase sensitivity but lead to longer response times. In this work,both fluorescence probes and colorimetric probes are integrated into a microfluidic paper strip.Both probes are incorporated into a single microfluidic paper strip to optimize sensitivity andefficiency. As a result, the use of colorimetric probes allows for the advantages of antibodyabsorption to be utilized for a short response time to detect antigens without need an extraexcitation source while fluorescent probes increase detection sensitivity and compensate forthe low sensitivity of colorimetric probes. The dual-signal probe displays capacity for greatlyimproving the accuracy and timeliness of standard Covid-19 detection in test kits.

Solute imbibition in paper strip: Pore-scale insights into the concentration-dependent permeability

Capillary wicking in a thicker gel blot microfluidics paper has been investigated through a combination of an analytical framework, experiments, and numerical simulations. The primary objectives of this work are to investigate the concentration-dependent wicking process inside thicker microfluidic paper and to estimate the concentration-dependent permeability using both theoretical models and experimental data. An additional goal is to estimate the parameters for saturation-dependent flow modeling in thicker microfluidic paper. To comprehend the wicking phenomenon on thicker gel blot paper, a series of experiments employing aqueous food dye solutions at varying concentrations has been conducted. In order to calculate the temporal wicking length analytically, the Brinkman-extended Darcy equation is implemented. By modifying the permeability expression for a simple rectangular unidirectional fiber cell and pure liquid, the expression of effective permeability for the analytical framework has also been introduced. The concentrations of the food dye solutions appear to have a substantial influence on the wicking phenomenon. Effective permeability and wicking length have been found to follow a decreasing pattern at lower concentrations while both increase at higher values. Intriguingly, employing a microfluidics paper with a relatively greater thickness facilitates the visualization of the fluid front. This phenomenon is identified by the formation of an acute angle at intermediate time instants, while the fluid front angle assumes an angle nearly ∼90° during smaller and higher time instants. In order to evaluate the saturation-dependent capillary pressure and permeability, the empirical correlation of concentration-dependent Brooks and Corey parameters is additionally determined experimentally. These parameters are subsequently employed in numerical simulations to illustrate the saturation-dependent flow field using Richards’ equation. Furthermore, numerical simulations based on these estimated model parameters have been conducted, and it turns out that the saturation field has an excellent agreement with the experimental results. The results of the current study can be used to design low-cost paper-based diagnostic devices for usage in healthcare and environmental applications.

Construction of fluorescent sensor array and three-dimensional microfluidic paper based analytical device for specific identification and visual determination of antibiotics in food.

For antibiotics misuse since the global outbreak of COVID 19, a novel strategy for discriminating and detecting antibiotics is proposed based on the graphene quantum dots with multi-doped heteroatoms including F, N and P (M-GQDs), which exhibit blue emission (419.0nm) under the excitation of 336.0nm. Specifically, the fluorescence of M-GQDs is quenched by tetracyclines (TCs) owing to inner filter effect (IFE) and enhanced by alkane-modified fluoroquinolones (AFQs), which is attributed to restricted conformational rotation based on π-π stacking, hydrogen-bonding and electrostatic interactions. Meanwhile, the electron-accepting property of oxazine ring in oxazine-modified fluoroquinolones (OFQs) increases emission peak at 498.0nm and decreases emission peak at 419.0nm as the color changes from blue to cyan. Moreover, a cascade system integrated with 3D microfluidic paper-based analytical device (3D-μPAD) is applied successfully for visually distinguishing three antibiotics, which shows great potential and versatility of M-GQDs for food safety monitoring.

Dual-channel foldable microfluidic paper-based parallel enzymatic reaction systems for simultaneous visual colorimetric detecting acetylcholinesterase and α-glucosidase together with screening inhibitors

On-site multi-enzymes detection and inhibitors screening are still challenging and particularly urgent. Here, dual-channel foldable microfluidic paper (μPAD)-based parallel enzymatic reaction systems were fabricated for simultaneous visual colorimetric detecting acetylcholinesterase (AChE) and α-glucosidase (α-Glu) together with screening inhibitors. μPAD composing of two layers with dual channels was designed and prepared facilely by a permanent marker. AChE and α-Glu catalyze pre-loaded substrates into products (thiocholine (TCh), ascorbic acid (AA)) on the 1st layer. Parallelly, oxidase-like MnO2 nanosheets oxidize pre-dropped colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) on the 2nd layer. After simple folding μPAD, TCh and AA can reduce oxTMB to TMB, resulting in color fading. Obviously, bioenzyme and nanozyme reactions under different pH can simultaneously occur on the μPAD. Furthermore, colorimetric results can be easily captured and on-site quantitatively analyzed by smartphone. As a result, a convenient, efficient, sensitive, and specific platform has been constructed for simultaneous detecting AChE and α-Glu in human serum samples (recoveries, 92.1–105.0%; relative standard deviations, < 3.6%), and screening inhibitors from synthesized compounds and natural products. The developed platform provides constructive insights for exploitation of visual detecting strategies for simultaneous sensing muti-targets for point-of-care testing of disease and development of drugs.

Gold Nanomaterial-Based Microfluidic Paper Analytical Device for Simultaneous Quantification of Gram-Negative Bacteria and Nitrite Ions in Water Samples.

This study presents a rapid microfluidic paper-based analytical device (μPAD) capable of simultaneously monitoring Gram-negative bacteria and nitrite ions (NO2-) for water quality monitoring. We utilize gold nanoparticles (AuNPs) functionalized with polymyxin molecules (AuNPs@polymyxin) to cause color change due to aggregation for the detection of Gram-negative bacteria, and antiaggregation in the presence of o-phenylenediamine (OPD) for NO2- detection. In this study, Escherichia coli (E. coli) serves as the model of a Gram-negative bacterium. Using the developed μPADs, the color changes resulting from aggregation and antiaggregation reactions are measured using a smartphone application. The linear detection ranges from 5.0 × 102 to 5.0 × 105 CFU/mL (R2 = 0.9961) for E. coli and 0.20 to 2.0 μmol/L (R2 = 0.995) for NO2-. The detection limits were determined as 2.0 × 102 CFU/mL for E. coli and 0.18 μmol/L for NO2-. Notably, the newly developed assay exhibited high selectivity with no interference from Gram-positive bacteria. Additionally, we obtained acceptable recovery for monitoring E. coli and NO2- in drinking water samples with no significant difference between our method and a commercial assay by t test validation. The sensor was also employed for assessing the quality of the pond and environmental water source. Notably, this approach can also be applied to human urine samples with satisfactory accuracy. Furthermore, the assay's stability is extended due to its reliance on AuNPs rather than reagents like antibodies and enzymes, reducing costs and ensuring long-term viability. Our cost-effective μPADs therefore provide a real-time analysis of both contaminants, making them suitable for assessing water quality in resource-limited settings.

A surface molecularly imprinted microfluidic paper based device with smartphone assisted colorimetric detection for butachlor in mung bean

A microfluidic paper chip colorimetric detection system based on surface molecular imprinting of zinc ferrite nanoparticles was established, and the detection images were obtained by smartphone for gray value analysis and determination of butachlor. The best functional monomers and addition ratio were selected by quantum chemical simulation calculation, the properties of the prepared molecularly imprinted polymers were analyzed, and the detection conditions were optimized. The linear range, sensitivity, and selectivity of the method were evaluated. The results showed that under the optimum conditions, the concentration of 2–80 ng/g had a good linear relationship (R2 is 0.9953), the detection limit was 1.43 ng/g, the specificity was good, and the whole detection process did not exceed 20 min. The microfluidic paper chip was applied to detect butachlor in mung bean samples. The results showed that the recovery was 93.4–106.4 %, and the relative standard deviation was less than 5.6 %.

Recent Uses of Paper Microfluidics in Isothermal Nucleic Acid Amplification Tests.

Isothermal nucleic acid amplification tests have recently gained popularity over polymerase chain reaction (PCR), as they only require a constant temperature and significantly simplify nucleic acid amplification. Recently, numerous attempts have been made to incorporate paper microfluidics into these isothermal amplification tests. Paper microfluidics (including lateral flow strips) have been used to extract nucleic acids, amplify the target gene, and detect amplified products, all toward automating the process. We investigated the literature from 2020 to the present, i.e., since the onset of the COVID-19 pandemic, during which a significant surge in isothermal amplification tests has been observed. Paper microfluidic detection has been used extensively for recombinase polymerase amplification (RPA) and its related methods, along with loop-mediated isothermal amplification (LAMP) and rolling circle amplification (RCA). Detection was conducted primarily with colorimetric and fluorometric methods, although a few publications demonstrated flow distance- and surface-enhanced Raman spectroscopic (SERS)-based detection. A good number of publications could be found that demonstrated both amplification and detection on paper microfluidic platforms. A small number of publications could be found that showed extraction or all three procedures (i.e., fully integrated systems) on paper microfluidic platforms, necessitating the need for future work.

Engineering Surface-Enhanced Raman Scattering Probe for Enhanced Detection of Acute Diseases with Paper Microfluidics

Effective and fast detection of acute diseases is still a main challenge for early diagnosis and monitoring treatment. In this work, surface-enhanced Raman scattering (SERS) probes are incorporated into a microfluidic paper strip for antigen biomarker detection. First, a new material is designed to tune plasmon band position and intensity. Second, geometry is optimized to maximize the SERS enhancement factor. The Finite-Difference Time-Domain simulation has confirmed that more hotspots are generated by the above optimization. As a results, the paper microfluidic strip has achieved the limit of detection at pg/mL level toward antigen detection in blood plasma. The paper microfluidic device shows a great potential in early detection of acute diseases at home, clinics, and remote areas with limited resources.

Hinge-like paper-based dual-channel enzyme-free ratiometric fluorescent microfluidic platform for simultaneous visual detection of carbaryl and glyphosate

On-site multi-pesticide residues detection is particularly urgent and challenging. Here, we fabricated an enzyme-free ratiometric fluorescent detection system in combination with a hinge-like dual-channel 3D microfluidic paper analytical device (3D μPAD) for simultaneous visual detection of carbaryl and glyphosate. Blue-emission 1-naphthol (Em. 470 nm) was hydrolyzed from carbaryl, while yellow-emission 2,3-diaminophenazine (Em. 570 nm) was produced with the aid of Cu2+ for glyphosate sensing. Inner-filter effect between 1-naphthol or 2,3-diaminophenazine and green-emission carbon dots (Em. 510 nm) realized two ratiometric fluorescent detection systems. Remarkable color variation of green–blue for carbaryl (50.00–1100 μΜ) and yellow–green for glyphosate (5.00–600 μΜ) were observed on a dual-channel 3D μPAD without crosstalk. Their detection limits were 1.11 and 0.63 μΜ, respectively. The strategy realized simultaneous visual detection of carbaryl and glyphosate in food/herbal with excellent accuracy (spiked recoveries, 91.00–107.2%), high precision (RSD ≤ 8.43%), and superior selectivity.

Paper-based multiplexed colorimetric biosensing of cardiac and lipid biomarkers integrated with machine learning for accurate acute myocardial infarction early diagnosis and prognosis

This study demonstrates how a colorimetric biosensor based on microfluidic paper can swiftly diagnose a disease and predict its prognosis to triage patients effectively. This was the first biosensor to quantify the gold standard cardiac troponin (cTnI) and lipid biomarkers, including high-density lipoprotein (HDL) and low-density lipoprotein (LDL) simultaneously. Prior research encountered obstacles or limitations, such as measuring a single biomarker or total cholesterol, which cannot distinguish between LDL and HDL. CatBoost, an advanced machine learning (ML) technique used for diagnosis that combines the predictive power of ML algorithms obtained an impressive area under the receiver operating curves (AUROC) of 0.97 ± 0.018 for all possible classification thresholds. CatBoost is a brand-new ensemble framework based on the interaction of multiple health parameters that can generate AUROC values of 0.897 ± 0.047 for the accurate prognosis of recurrent acute myocardial infarction (AMI), demonstrating remarkably accurate AMI diagnosis and prognosis. In addition, this paper-based analytical device (µPAD) biosensor employs an electrophoretic method to overcome the challenges posed by non-specific adsorption. This is accomplished by isolating non-specific biomolecules based on differences in their isoelectric points and removing non-specifically adsorbing colorimetric markers. The limits of detection (LoD) for cTnI in AMI were lower than their respective clinical cutoff values. This study also demonstrated that the proposed ML framework produced significantly better results than conventional statistical analysis. High correlation filtering and (t-SNE) dimensionality reduction were utilized for a limited number of data points. The respectable accuracy and AUROC of this method were also validated using cross-validation.

Microfluidic paper chip based multicolor chemiluminescence sensing strategy for discrimination of antioxidants

The development of chemiluminescence (CL) sensing strategy with multiple-parameters for discrimination of small molecules remains a great challenge. Herein, a multicolor CL sensing strategy for the discrimination of five antioxidants, including dopamine, catechin, cysteine, glutathione, and thioctic acid was presented. Firstly, multilayer paper chips modified with luminol-Co(II), luminol-fluorescein-Co(II), and luminol-rhodamine B-Co(II) that can produce strong blue, green and purple colored light emission, respectively, via CL and CL resonance energy transfer (CRET) reactions were fabricated. The presence of antioxidants exhibits different inhibition or enhancement effect on the CL reactions, creating unique multicolor CL response pattern to each antioxidant. The red (R), green (G), and blue (B) channel split from the purple, green and blue CL image, respectively, generate cross-reactive sensing parameters for the discrimination of the five antioxidants. The distinct R, G, and B values of the CL images to each antioxidant are created as analytical fingerprints to identify five antioxidants by using principal component analysis and hierarchical cluster analysis. Satisfied results were obtained for discrimination antioxidant mixtures and spiked antioxidants in serum samples. Identification of 10 unknown samples resulted in 100% accuracy. This work presents the first example of multicolor CL sensing strategy for the discrimination of small molecules.

Sensitive and simple multi-ion detection using organic nanocrystal enrichment in paper analytical devices

Microfluidic paper analytical devices (μPADs) are among the most promising platforms for heavy metal ion analysis. On the other hand, achieving simple and highly sensitive analysis of μPADs is challenging. In this study, we developed a simple enrichment method for sensitive multi-ion detection utilizing water-insoluble organic nanocrystals accumulated on μPAD. By combining the enrichment method with multivariate data analysis, three metal ion concentrations in the ion mixtures were simultaneously quantified with high sensitivity owing to the sensitive responses of the organic nanocrystals. In this work, we successfully quantified Zn2+, Cu2+, and Ni2+ at 20 ng L−1 in the mixed ion solution using only two dye indicators with a larger sensitivity improvement than those reported in previous studies. Interference studies revealed possibilities for a practical application in real sample analysis. This developed approach also can be used for other analytes.

Paper microfluidics with deep learning for portable intelligent nucleic acid amplification tests.

During global outbreaks such as COVID-19, regular nucleic acid amplification tests (NAATs) have posed unprecedented burden on hospital resources. Data of traditional NAATs are manually analyzed post assay. Integration of artificial intelligence (AI) with on-chip assays give rise to novel analytical platforms via data-driven models. Here, we combined paper microfluidics, portable optoelectronic system with deep learning for SARS-CoV-2 detection. The system was quite streamlined with low power dissipation. Pixel by pixel signals reflecting amplification of synthesized SARS-CoV-2 templates (containing ORF1ab, N and E genes) can be real-time processed. Then, the data were synchronously fed to the neural networks for early prediction analysis. Instead of the quantification cycle (Cq) based analytics, reaction dynamics hidden at the early stage of amplification curve were utilized by neural networks for predicting subsequent data. Qualitative and quantitative analysis of the 40-cycle NAATs can be achieved at the end of 22nd cycle, reducing time cost by 45%. In particular, the attention mechanism based deep learning model trained by microfluidics-generated data can be seamlessly adapted to multiple clinical datasets including readouts of SARS-CoV-2 detection. Accuracy, sensitivity and specificity of the prediction can reach up to 98.1%, 97.6% and 98.6%, respectively. The approach can be compatible with the most advanced sensing technologies and AI algorithms to inspire ample innovations in fields of fundamental research and clinical settings.

Distance-based paper microfluidics as environmentally friendly platforms for monitoring acid-base titrations

The goal of green chemistry is to reduce the impact of chemical processes on the environment. In this context, it is important to develop new analytical tools that comply with the principles of green analytical chemistry (GAC) to contribute to the sustainable development of the planet. This study describes the development of an environmentally friendly methodology using paper-based analytical devices (µPADs) to perform acid-base titrations by distance-based measurements. The devices were composed of a circular zone defined with 5 mm diameter connected to a rectangular channel of 40 mm long × 3 mm wide. The titrations of acidic (strong and weak) and alkaline (strong and weak) solutions were successfully demonstrated using 10 µL of titrant solution and 10 µL of sample solution. The solution added into the zone travels different distances depending on the concentration of the titrated, thus promoting the channel coloration or discoloration. The distance measurements covered by the titrated solutions were obtained recorded with a digital caliper. As proof-of-concept for quantitative purposes, the µPAD was then used to determine the acetic acid content in commercial vinegar. The average distances ranged from to 32.0 to 32.5 mm and the concentration values ranged from 4.3 to 4.6% (m/v). Conventional acid-base volumetry was used as a control method, and the obtained results demonstrated no statistical difference at 95% confidence level. Lastly, the 12 principles of GAC were analyzed to evaluate the suitability of the proposed method. Considering a unified scale between 0 and 1, the final green value was 0.72. Titrations with distance-based detection on µPADs were found to be a technique with fast responses and low cost that can be used as a replacement for conventional practices in teaching laboratories or adapted for the detection of different analytes.

A dual-channel and dual-signal microfluidic paper chip for simultaneous rapid detection of difenoconazole and mancozeb

Using L-cysteine (L-Cys) modified carbon quantum dots (CQDs) and CdTe quantum dots (CdTe QDs) as fluorescence signals, we developed a novel dual-channel and dual-signal microfluidic paper chip, which enables portable and rapid analysis of difenoconazole and mancozeb by internal filter effect (IFE) and photoinduced electron transfer (PET), respectively. The results indicate that the two single-fluorescence imprinted paper chips have great stability and fluorescence property, and the dual-channel microfluidic paper chip composed of them can achieve simultaneous rapid detection of difenoconazole and mancozeb in a mixed solution. The rapid quantitative detection of two templates was achieved under the same excitation wavelength (360 nm) within 5 min. The limits of detection of difenoconazole and mancozeb were 0.18 μg/mL and 2 μg/mL, respectively. Furthermore, the dual-channel microfluidic paper chip also had good specific recognition for their analogs. Moreover, its recoveries of the actual samples were 102.2–108.8% and 96.0–105.5%, respectively, and the relative standard deviations were all less than 5.6%. In conclusion, this work has successfully prepared a multi-template rapid quantitative pesticide residue detection sensor, which provides a useful exploration for the development of new universal rapid detection technologies and theories and is of great significance for the rapid detection of pesticide residues in export products.

Biomarker Detection in Early Diagnosis of Cancer: Recent Achievements in Point-of-Care Devices Based on Paper Microfluidics

Microfluidics is very crucial in lab-on-a-chip systems for carrying out operations in a large-scale laboratory environment on a single chip. Microfluidic systems are miniaturized devices in which the fluid behavior and control can be manipulated on a small platform, with surface forces on the platform being greater than volumetric forces depending on the test method used. In recent years, paper-based microfluidic analytical devices (μPADs) have been developed to be used in point-of-care (POC) technologies. μPADs have numerous advantages, including ease of use, low cost, capillary action liquid transfer without the need for power, the ability to store reagents in active form in the fiber network, and the capability to perform multiple tests using various measurement techniques. These benefits are critical in the advancement of paper-based microfluidics in the fields of disease diagnosis, drug application, and environment and food safety. Cancer is one of the most critical diseases for early detection all around the world. Detecting cancer-specific biomarkers provides significant data for both early diagnosis and controlling the disease progression. μPADs for cancer biomarker detection hold great promise for improving cure rates, quality of life, and minimizing treatment costs. Although various types of bioanalytical platforms are available for the detection of cancer biomarkers, there are limited studies and critical reviews on paper-based microfluidic platforms in the literature. Hence, this article aims to draw attention to these gaps in the literature as well as the features that future platforms should have.

Paper-Based Loop Mediated Isothermal Amplification (LAMP) Platforms: Integrating the Versatility of Paper Microfluidics with Accuracy of Nucleic Acid Amplification Tests

Paper-based diagnostics offer a promising alternative to traditional diagnostic methods for point-of-care use due to their low cost, ease of use, portability, rapid results, versatility, and low environmental impact. While paper-based serology tests in the form of lateral flow assays can provide rapid test results for past pathogen exposure, they currently lack the accuracy and sensitivity offered by molecular diagnostic tests such as the polymerase chain reaction (PCR). Loop-mediated isothermal amplification (LAMP)—an isothermal nucleic acid amplification test (NAAT)—provides PCR-like performance while simultaneously reducing the instrumentation and assay complexity associated with PCR. In this review, we discuss a newly emerging class of paper-based LAMP platforms that integrates the versatility of paper microfluidics with the accuracy of NAATs. Since its first adoption in 2015, we have discussed all paper-based LAMP platforms in terms of the paper substrates, reagent incorporation techniques, paper platform design, heating hardware, detection methods, and sensitivity and specificity of paper-based LAMP assays. We conclude by identifying the current challenges and future prospects of paper-based NAATs.