Simple Instrument Research Articles

Light-field flow cytometry for high-resolution, volumetric and multiparametric 3D single-cell analysis

Imaging flow cytometry (IFC) combines flow cytometry and fluorescence microscopy to enable high-throughput, multiparametric single-cell analysis with rich spatial details. However, current IFC techniques remain limited in their ability to reveal subcellular information with a high 3D resolution, throughput, sensitivity, and instrumental simplicity. In this study, we introduce a light-field flow cytometer (LFC), an IFC system capable of high-content, single-shot, and multi-color acquisition of up to 5,750 cells per second with a near-diffraction-limited resolution of 400-600 nm in all three dimensions. The LFC system integrates optical, microfluidic, and computational strategies to facilitate the volumetric visualization of various 3D subcellular characteristics through convenient access to commonly used epi-fluorescence platforms. We demonstrate the effectiveness of LFC in assaying, analyzing, and enumerating intricate subcellular morphology, function, and heterogeneity using various phantoms and biological specimens. The advancement offered by the LFC system presents a promising methodological pathway for broad cell biological and translational discoveries, with the potential for widespread adoption in biomedical research.

Tunable Self-Referenced Molecular Thermometers via Manipulation of Dual Emission in Platinum(II) Pyridinedipyrrolide Complexes.

Optical temperature sensors based on self-referenced readout schemes such as the emission ratio and the decay time are crucial for a wide range of applications, with the former often preferred due to simplicity of instrumentation. This work describes a new group of dually emitting dyes, platinum(II) pincer complexes, that can be used directly for ratiometric temperature sensing without an additional reference material. They consist of Pt(II) metal center surrounded by a pyridinedipyrrolide ligand (PDP) and a terminal ligand (benzonitrile, pyridine, 1-butylimidazol or carbon monoxide). Upon excitation with blue light, these complexes exhibit green to orange emission, with quantum yields in anoxic toluene at 25 °C ranging from 13% to 86% and decay times spanning from 8.5 to 97 μs. The emission is attributed to simultaneous thermally activated delayed fluorescence (TADF) and phosphorescence processes on the basis of photophysical investigations and DFT calculations. Rather uniquely, simple manipulations in substituents of the PDP ligand and alteration of the terminal ligand allow fine-tuning of the ratio between TADF and phosphorescence from almost 100% TADF emission (Pt(MesPDPC6F5(BN)) to over 80% of phosphorescence (Pt(PhPDPPh(BuIm)). Apart from ratiometric capabilities, the complexes also are useful as decay time-based temperature indicators with temperature coefficients exceeding 1.5% K-1 in most cases. Immobilization of the dyes into oxygen-impermeable polyacrylonitrile produces temperature sensing materials that can be read out with an ordinary RGB camera or a smartphone. In addition, Pt(PhPDPPh)Py can be incorporated into biocompatible RL100 nanoparticles suitable for cellular nanothermometry, as we demonstrate with temperature measurements in multicellular colon cancer spheroids.

Endoscopic Mucosal Incision to Remove a Chain of Magnets Completely Embedded under the Gastric Mucosa

AbstractThe rising use of electronic toys containing magnets has led to an increased incidence of magnet ingestion in children. While endoscopic extraction is the preferred approach in these cases, challenges arise when multiple magnets get swallowed, which can erode through the mucosal surface and become embedded in fibrous tissue. Extraction using simple endoscopic techniques and instruments is not possible in such cases and many times, surgical intervention becomes necessary.This case showcases the application of cap-assisted endoscopic mucosal resection and endoscopic submucous dissection principles and the use of magnetic forceps, enabling the safe and complete removal of the embedded magnet pieces and highlighting the remarkable effectiveness of advanced endoscopic techniques in managing this unique challenge. The multidisciplinary approach and tailored interventions demonstrated in this case underscore the importance of prompt and comprehensive evaluation in cases of ingested foreign bodies, particularly those involving multiple magnets

Striking a (vocal) chord: musical instruments as mnemonic devices when teaching the functional anatomy of the larynx.

Mnemonic devices are memory aids that make it easier to recall information and are widely used by students studying anatomy and physiology. Simple musical instruments and toys can serve as mnemonic devices for students learning the functional anatomy of the larynx: balloons can help learners understand and recall how sound is produced; tuning pegs can help learners understand how tension affects vocal pitch; fingers on a fretboard can help learners understand how pitch is further modulated; and a common coach's whistle can demonstrate how vocal volume is controlled. Using instruments and toys engages adult learners and helps them connect complex laryngeal anatomy with previous experiences.NEW & NOTEWORTHY Musical instruments and toys can be used as mnemonic devices to help students recall and understand the functional anatomy of voice production. The mnemonics can be implemented in a variety of classrooms and are flexible and engaging.

Sensitive Methods to Detect Single-Stranded Nucleic Acids of Food Pathogens Based on Cell-Free Protein Synthesis and Retroreflection Signal Detection.

Cell-free protein synthesis (CFPS) has recently gained considerable attention as a new platform for developing methods to detect various molecules, ranging from small chemicals to biological macromolecules. Retroreflection has been used as an alternative signal to develop analytical methods because it can be detected by using a simple instrument comprising a white light source and a camera. Here, we report a novel reporter protein that couples the capability of CFPS and the simplicity of retroreflection signal detection. The design of the reporter was based on two pairs of protein-peptide interactions, SpyCatcher003-SpyTag003 and MDM2-PMI(N8A). MDM2-MDM2-SpyCatcher003 was decided as the reporter protein, and the two peptides, SpyTag003 and PMI(N8A), were immobilized on the surfaces of retroreflective Janus particles and microfluidic chips, respectively. The developed retroreflection signal detection system was combined with a previously reported CFPS reaction that can transduce the presence of a single-stranded nucleic acid into protein synthesis. The resulting methods were applied to detect 16S rRNAs of several foodborne pathogens. Concentration-dependent relationships were observed over a range of 10° fM to 102 pM, with the limits of detection being single-digit femtomolar concentrations. Considering the designability of the CFPS system for other targets, the retroreflection signal detection method will enable the development of novel methods to detect various molecules.

Easy-to-Use Chemiluminescent-Based Assay for a Rapid and Low-Cost Evaluation of the Antioxidant Activity of Cosmetic Products

New cosmetic formulations are continuously requested by the market and the ingredients are constantly evolving. Recently the use of antioxidants has gained success and, in this context, analytical methods able to quickly and easily assess the antioxidant activity of cosmetics would make it possible to carry out analyses on new formulations even within the manufacturing process without the need for specialized laboratories and personnel, thus evaluating directly on-site the effectiveness and the shelf life of products. In this work, a chemiluminescent inhibition assay was developed for determining the total antioxidant activity in cosmetic products. The method was based on the luminol/enhancers/hydrogen peroxide/horseradish peroxidase chemiluminescent system, which generates light signals measurable through simple and compact instrumentation. The formation of the chemiluminescent signal is inhibited by the presence of antioxidant substances while it is restored once all the antioxidant molecules have been oxidized. The time of appearance of the light signal is related to the total antioxidant activity. The assay was carried out exploiting an integrated device comprising a microwell plate coupled with an array of amorphous silicon hydrogenated photosensors enclosed in a mini-dark box. The method was optimized in terms of concentrations and volumes of the required reagents and sample pre-treatment. A calibration curve was generated taking as a reference the antioxidant activity of ascorbic acid obtaining a detection limit of 10 µM. The developed method was applied to cosmetic products currently on the market as well as on spiked samples in order to evaluate the performance of the methods in terms of sensitivity, accuracy, and reproducibility.

Clinical usefulness of the patient-generated subjective global assessment short form© for nutritional screening in patients with head and neck cancer: a multicentric study.

Nutritional screening and assessment are considered essential steps in nutritional care for cancer patients, malnutrition remains underreported in clinical practice. The aim of this study was to analyse the clinical usefulness of the Patient-Generated Subjective Global Assessment short form (PG-SGA SF©) for nutritional screening in patients with head and neck cancer (HNC). This is a multicentre, cross-sectional study involving patients with HNC. The final score of the PG-SGA SF© was obtained and the nutritional status was diagnosed using the Patient-Generated Subjective Global Assessment (PG-SGA)®, classifying them as well-nourished or malnourished. Receiver operating characteristic curve, ordinal logistic regression, and C-statistic were used. In total, 353 patients with HNC were enrolled and the prevalence of malnutrition, according to the PG-SGA®, was 64.02% and the median final score of PG-SGA SF© was 11 points. The final score of the PG-SGA SF© had high accuracy (area under the curve = 0.915), and scores ≥9 had the best performance in diagnosing malnutrition. PG-SGA SF© final score ≥9 was associated with malnutrition (odds ratio = 28.32, 95% confidence interval= 15.98-50.17), with excellent discriminatory power (C-statistic = 0.872). In conclusion, the PG-SGA SF© demonstrated excellent performance for nutritional screening in patients with HNC. Given that it is a simple instrument that is faster to administer than the PG-SGA®, we recommend its use in clinical practice among such patients.

Directional-sensitive wide field-of-view monitoring of high-intensity proton beams by spectral tracking of scattered particles with scattering foil and miniaturized radiation camera

Monitoring and characterization of particle beams in wide-range is often necessary in research and many applications with particle accelerators. The quantitative measurement and evaluation of composition especially of high-intensity beams are limited and can become a challenge with conventional methods especially with simplified instrumentation for ease of deployment. For this purpose, we developed a novel technique based on high-resolution spectral-sensitive tracking of single particles scattered from the beam path by a thin foil. We use a compact radiation camera equipped with the semiconductor pixel detector Timepix3 together with dedicated Monte-Carlo simulations. Particle-event type discrimination and directional information are produced by the detector spectral-tracking response together with particle-type resolving power derived from experimental calibrations. Directional- and spectral-sensitive components can be resolved in wide field-of-view. Quantification of the primary beam intensity is extrapolated by numerical calculations. Demonstration and evaluation of the technique are provided by measurements with 33 MeV protons from a light ion cyclotron accelerator.Scattered particles originating from the thin foil, the accelerator beam nozzle, and the air space along the beam path are detected and evaluated.

Validity of PDQ4+ self-screening to assess the impact of personality disorder traits on the course of bipolar disorder

BackgroundPatients with bipolar disorder (BD) and comorbid personality disorder (PD) have a less favorable illness course than those without comorbidity. They are more difficult to stabilize and make more use of mental health care. This may also be true for PD traits that do not meet criteria for a specific PD. The aim of this study is to investigate whether a simple self-screening instrument (PDQ-4+) can provide an indication of expected severity and course of BD. MethodsPatients completed the PDQ-4+ and the treating clinician independently assessed retrospectively over the past 12 months the course of BD (number of depressive and (hypo)manic episodes, number and duration of hospitalizations, and suicide attempts) and the overall severity of illness using the Clinical Global Impression scale for BP (CGI-BP). Mann-Whitney U tests were used for group comparisons. Spearman rho was used to evaluate associations between the prevalence of PD traits and course of BD. ResultsThe prevalence of a positive PD screening in the sample with BD was 57.5 %. Patients who screened positive on specific PD were on average rated as more severely ill. More importantly, the total number of all dysfunctional personality traits was associated with less favorable course of BD and had a higher validity than any individual PDs. A limitation of our study is the small sample size and retrospective assessment of BD course. ConclusionScreening with PDQ-4+ helps to identify a group at risk for a more severe illness course of BD. More important than meeting formal criteria for any PD are the accumulation of dysfunctional personality traits in patients with BD.

Electrochemical aptamer-based biosensing of glycan-conjugated targets

As the most complex post-translational modification, glycosylation involves the covalent linking of glycan(s) to a biomolecule. The glycosylation of proteins, peptides, lipids, and nucleic acids results in the formation of diverse glycoconjugates, like glycoproteins, peptidoglycans, glycopeptides, glycolipids, lipopolysaccharides, and glycoRNAs, and glycoconjugates are also ubiquitous on the surface of extracellular vesicles (EVs), cells, bacteria, and viruses. The conjugated glycans are integral to cell recognition (e.g., adhesion and homing), cell trafficking, immune recognition, hormone-receptor binding, protein folding and stabilization, and many other biological processes. Currently, the glycan-conjugated biological objects have found widespread applications in disease diagnosis (e.g., glycoproteins, exosomes, and circulating tumor cells) and therapy (e.g., therapeutic monoclonal antibodies). Over the past decades, a variety of methods have been established for the quantitative assay of the glycan-conjugated biological objects, in light of their significant diagnostic and therapeutic values, using antibodies, aptamers, or affinity peptides as recognition ligands. Relative to other methods, the aptamer-based electrochemical biosensors (i.e., electrochemical aptasensors) have attracted much attention in recent years in the detection of the glycan-conjugated targets, by virtue of their intrinsic advantages such as low cost, good portability, simple instrument, superior stability and anti-interference capability, and high sensitivity and selectivity. This review summarizes the biological, diagnostic, and therapeutic significance of the glycan-conjugated biological objects, and then presents the progress in the electrochemical aptasensing of the glycan-conjugated biological objects, including glycoproteins, lipopolysaccharides (LPSs), exosomes, circulating tumor cells (CTCs), and pathogenic microbes (e.g., bacteria and viruses). Moreover, the challenges and future prospects of the electrochemical aptasensing of the glycan-conjugated biological objects are discussed.

The value of circadian heart rate variability for the estimation of obstructive sleep apnea severity in adult males.

Heart rate variability (HRV) is becoming more prevalent as a measurable parameter in wearable sleep-monitoring devices, which are simple and effective instruments for illness evaluation. Currently, most studies on investigating OSA severity and HRV have measured heart rates during wakefulness or sleep. Therefore, the objective of this study was to investigate the circadian rhythm of HRV in male patients with OSA and its value for the estimation of OSA severity using group-based trajectory modeling. Patients with complaints of snoring were enrolled from the Sleep Center of Shandong Qianfoshan Hospital. Patients were divided into 3 groups according to apnea hypopnea index (AHI inevents/h), as follows: (<15, 15≤AHI<30, and ≥30). HRV parameters were calculated using 24 h Holter monitoring, which included time-domain and frequency-domain indices. Circadian differences in the standard deviation of normal to normal (SDNN) were evaluated for OSA severity using analysis of variance, trajectory analysis, and multinomial logistic regression. A total of 228 patients were enrolled, 47 with mild OSA, 48 moderate, and 133 severe.Patients with severe OSA exhibited reduced triangular index and higher very low frequency than those in the other groups. Circadian HRV showed that nocturnal SDNN was considerably higher than daytime SDNN in patients with severe OSA. The difference among the OSA groups was significant at 23, 24, 2, and 3 o'clock sharp between the severe and moderate OSA groups (all P<0.05). The heterogeneity of circadian HRV trajectories in OSA was strongly associated with OSA severity, including sleep structure and hypoxia-related parameters. Among the low-to-low, low-to-high, high-to-low, and high-to-high groups, OSA severity in the low-to-high group was the most severe, especially compared with the low-to-low and high-to-low SDNN groups, respectively. Circadian HRV in patients with OSA emerged as low daytime and high nocturnal in SDNN, particularly in men with severe OSA. The heterogeneity of circadian HRV revealed that trajectories with low daytime and significantly high nighttime were more strongly associated with severe OSA. Thus, circadian HRV trajectories may be useful to identify the severity of OSA.

Simulation in pediatric minimally invasive surgery: adaptation of a simple series of exercises as part of the process of an initial implementation of a resident training program.

the simulation in minimally invasive surgery is fundamental for surgeon in training to learning and training skills, especially in pediatrics, due to the particularities, reduced spaces, specific and rare procedures. The aim of this study was to propose an adapted series of exercises and to simply evaluate the performance of pediatric surgery residents in the initial implementation of a training program. seven basic skills exercises in video surgery, based on series and programs already published and using low-cost materials, were performed by six residents in 2 moments, with an interval of 15 days and evaluated by simple instrument. there was no difficulty with models. Considering the individual averages of the seven exercises together in the two moments, five of the six residents increased the score in the second moment. The average score per exercise increased in five of the seven tasks. Despite the small number of participants and repetition, it has already been possible to observe a trend of better performance with decreased time of all residents after a single repetition. All considered the exercises capable of training essential skills of the specialty, with simple and inexpensive materials. given the challenges of simulated training in pediatric video surgery, it is known the benefit of a continuous program, with exercises that can simulate real situations. A pre-established schedule, more participants and repetitions, supervision of experienced surgeons and validated instruments are fundamental to evaluate surgeons in training and show statistical benefits of simulated exercises in this series.

Nanometrology based control: taming radical grafting reactions with attoliter precision.

Precisely controlled micropatterning with organic moieties is a promising route for designing smart surfaces, enabling the development of microsensors and actuators with optimal usage of reactants. Such applications require fine control over the surface modification process, which in turn demands detailed knowledge about the surface modification process. As complex surface kinetics often emerge as a result of even slight modifications of the grafting entity, non-invasive, sensitive and precise closed loop control strategies are highly desirable. In this paper we demonstrate that a nanometrology approach based on quantitative phase imaging (QPI) fulfill all these requirements. We first use the technique to monitor surface photografting kinetics of aryl radicals, comprehensively analyzing the effect of substituents on surface addition reactions. We demonstrate that several aspects of the grafting process are affected in complex ways, rendering open-loop strategies impossible to implement precisely. Then, we show that the operando optical phase signal can be used as a direct feedback, guiding the grafting reaction process. Using relatively simple instrumentation, we demonstrate that general and precise control strategies can be designed and used to control the volume of the grafting material with attoliter precision, in spite of radically different surface modification kinetics spanning several orders of magnitude.

Recent progress in electrochemical detection of amaranth in food samples: A brief review

Amaranth (E 123, AM) is a red synthetic azo dye authorized as a food additive in the EU. In contrast to natural colorants, AM has significant advantages such as low production cost, excellent water solubility, and high stability. AM is used to enhance the natural color, to decrease the loss of color due to processing treatments, and to provide color to colorless ultra-processed foods, making food more attractive to the consumers. AM is widely used in food industry to improve the appearance and color of different types of food and beverages, including confectionery products, jelly, candies, jams, dairy products, ice creams, sausages, wines, syrups and soft drinks. Many of these food products are manufactured directly for, and marketed directly to, children. The high amount of AM in food products can cause adverse health effects such as dizziness, allergies, and respiratory problems. Moreover, long-term studies indicated that the potential adverse effects induced by AM include genotoxicity and cytotoxicity. Therefore, the development of a precise and easy-to-handle alternative for a quick and efficient quantitative detection of AM in food products is necessary for consumer safety. Modern electroanalytical techniques have the advantages of excellent sensitivity and selectivity, instrumental simplicity and portability, providing reliable alternatives to the conventional analytical methods. In this brief review, we have summarized recent trends in the electrochemical sensor systems applied for the analysis of AM in food samples, critically evaluated the performance metrics of these sensors: sensitivity, linear range, limit of detection and stability. Finally, the current challenges and future prospects are outlined.

Gaya Kepemimpinan Kepala Desa dalam Meningkatkan Partisipasi Masyarakat pada Program Pembangunan Fisik Desa

This research aims to determine the leadership style and the factors behind the village head's leadership in increasing community participation in village development and to determine the stages of community participation in Tarawali Village. This research uses a qualitative method with a descriptive approach. The selection of informants used a purposive sampling technique. The findings show that: 1) the leadership style as assessed by the construction of irrigation, farming roads and houses of worship in Tarawali Village has quite good communication, good responsibility and good motivation, but on average, community participation is still lacking due to the leadership role the village head is considered not optimal; 2) types of community participation in Tarawali Village, namely initiative participation, legitimacy and execution. This research discusses leadership styles related to communication focus, responsibility and motivation. The originality is that this research discusses the factors behind the less-than-optimal development process in more depth. In addition, this research identifies types of community participation. This research has limitations in the number of informants and simple question instruments.

Analisis Tingkat Usabilitas Website Perguruan Tinggi Menggunakan System Usability Scale (SUS)

In the digital era, the existence of a website is a necessity for universities. Websites can be an effective marketing tool because they can reach higher education audiences globally without being limited by geographic boundaries. However, website managers must ensure that the website has good quality and visibility. One tool for measuring the level of website usability was the System Usability Scale (SUS). SUS was chosen because it was considered a simple instrument but can provide an overview of the level of website usability. This research involved 866 student website users. The measurement results show that the website obtained an SUS score of 61.4. This score was then interpreted into three scales, namely Grade Scales, Adjective Ratings and Acceptability Ranges. The results show that the score were categorized into the "D", "Good" and "Marginal Low" categories for the Grade Scales, Adjective Ratings and Acceptability Ranges respectively. This SUS score shows a fairly low level of usability, therefore website improvements, especially in terms of website visuals, are important to do immediately.

Psychometric Properties of the Slovenian Version of Brief Sensation Seeking Scale.

Sensation seeking (SS) is a psychobiological personality trait characterized by an individual's propensity to engage in various forms of risk-taking behavior. The Brief Sensation Seeking Scale (BSSS-8) is a widely used instrument for assessing SS that has been translated into several languages. However, only outdated and non-validated questionnaires have been used to measure SS in the Slovenian population. The aim of this study was to translate and psychometrically validate the Slovenian version of the BSSS-8. A total of 363 participants aged between 14 and 65 years completed the translated BSSS-8 and the questionnaire on drug abuse. The scale demonstrated good reliability (Cronbach's α=0.81) and a unidimensional factorial structure as revealed by confirmatory factor analysis (CFA). The multigroup CFA showed gender-specific measurement invariance. In the nomological network, SS was positively associated with drug-related variables. The Slovenian version of the BSSS-8 scale is a short and simple instrument to assess SS for research and epidemiological purposes.

Studies of ice physical properties in Russia and USSR (late XIXth century – 1940). Ice density and porosity

The paper deals with studies conducted in Russia and USSR of ice density, a most important characteristic of ice, and spans a period from the late XIXth century to 1940. It is shown that Russian scientists started their investigations of ice density only around the end of the XIX century, and those studies were often performed with specific applications in mind, e. g. works by B.P. Veinberg and his disciples in Tomsk in 1911–1914. In the USSR, there was a revival of interest in this kind of studies in the late 1920s in connection with explorations of the polar seas. Density measurements were mainly performed by hydrostatic weighing. At the request of N.N. Zubov and I.I. Mesyatsev in 1927 V.V. Shuleikin invented a simple instrument to measure ice density without weighing samples. In the early 1930s, ice porosity became an important field of research aimed at finding the causes of variance of experimental data on ice density. Ice porosity and density were studied using innovative devices developed by V.V. Shuleikin and V.I. Arnold-Alyabiev, which allowed studying ice properties in expedition conditions. The device developed by Arnold-Alyabiev found widespread use in field studies. Ice density and porosity are closely related physical quantities, therefore measuring the porosity of ice allowed researchers to estimate its density. By the end of the 1930s the ice density measurements had developed into a standard procedure of ice studies, which was due in large measure to the plans devised at the All-Union Arctic Institute headed by B.P. Veinberg to investigate ice at polar stations, which also included ice density and porosity studies.

Miniaturization of an enclosed electrospinning process to enhance reproducibility in the fabrication of rapidly dissolving cell-based biosensors.

There is broad interest in producing electrospun films embedded with biological materials. It is well known that electrospinning requires careful control of the process conditions, especially the environmental conditions such as relative humidity (RH). Given that commercial electrospinning systems are expensive (>$10,000) and are typically too large to be used in standard biological safety cabinets (BSC), we designed and built a miniaturized electrospinning box (E-Box) that will fit inside a BSC, and the RH can be easily controlled using simple instrumentation (gas cylinder, regulator, needle valve, rotameter). It uses an inexpensive computerized numerical control machine to control the spinneret positioning and collector rotational speed-all the parts for the device (except the syringe pump and voltage supply) can be purchased for approximately $1000. We demonstrate the usefulness of our design in optimizing the production of Escherichia coli-embedded pullulan-trehalose films to be used as rapidly dissolving biosensors for environmental monitoring. At a fixed electrospinning recipe, we showed that decreasing the RH from approximately 48% to 22% resulted in the average fiber diameter increasing from 240(±11) nm to 314(±8) nm. We also demonstrate the usefulness of our design in performing sequential electrospinning experiments to evaluate process performance reproducibility. For example, from just 1mL of a polymer solution, we produced 16 electrospun films (approximately 3cm by 8cm each)-from those films we hole-punched approximately 80 biosensor discs which were then used in subsequent experiments to determine the amount of two different biocides (Grotan BK and triclosan) in aqueous samples. The technique developed in this study is ideal for creating electrospun materials in high quantities that are highly reproducible through the precise control of RH.

A novel ratiometric electrochemical aptasensor based on M-shaped functional DNA complexes for simultaneous detection of trace lead and mercury ions in series aquatic edible vegetables

Simultaneous quantification of multiple heavy metal ions (HMIs) is essential due to enhanced toxicity induced by synergistic effects. The currently available detection methods suffer from drawbacks such as costly devices, poor anti-interference, and specificity. In this work, a ratiometric electrochemical aptasensor for simultaneous detection of trace lead (Pb2+) and mercury ions (Hg2+) was developed. Here, a metal-organic framework, UiO-66-CNTs, with inherent and stable electrochemical signal was used for loading complementary strands (CSs) and internal reference. Guanine-rich and thymine-rich oligonucleotides, labelled with carbon dots (CDs), acted as aptamers (Apts) and hybridized with CSs to form M-shaped DNA complexes. Pb2+ and Hg2+ could be recognized and captured by Apts to form Pb2+-G-quadruplex and T-Hg2+-T complexes, leading to the destruction of M-shaped DNA complexes and changes in CDs’ signal. The current ratios, ICDs/IUiO-66-CNTs, were applied to quantify Pb2+ and Hg2+. Benefiting from the anti-interference ability of the ratiometric strategy and the specificity of Apts, the proposed method enabled detection Pb2+ and Hg2+ through simple instrumentation, with detection limits of 2.0 ng mL−1 and 0.5 ng mL−1. Moreover, it was applied to assess Pb2+ and Hg2+ contamination in series of aquatic edible vegetables. The experimental results were consistent with inductively coupled plasma-mass spectrometry (ICP-MS), demonstrating its potential in practical applications.