Glucometer Readout Research Articles

Core-shell "loading-type" nanomaterials enabling glucometer readout for portable and sensitive detection of p-aminophenol in real samples.

A one-target-many-trigger signal model sensing strategy is proposed for quickly, sensitive and on-site detection of the environmental pollutant p-aminophenol (PAP) by use of a commercial personal glucose meter (PGM) for signal readout with the core-shell "loading-type" nanomaterial MSNs@MnO2 as amplifiable nanoprobes. In this design, the mesoporous silica nanoparticles (MSNs) nanocontainer with entrapped signal molecule glucose is coated with redoxable manganese dioxide (MnO2) nanosheets to form the amplifiable nanoprobes (Glu-MSNs@MnO2). When encountered with PAP, the redox reaction between the MnO2 and PAP can induce the degradation of the outer layer of MSNs@MnO2, liberating multiple copies of the loaded glucose to light up the PGM signal. Owing to the high loading capability of nanocarriers, a "one-to-many" relationship exists between the target and the signal molecule glucose, which can generate adequate signal outputs to achieve the requirement of on-site determination of environmental pollutants. Taking advantage of this amplification mode, the developed PAP assay owns a dynamic linear range of 10.0-400μM with a detection limit of 2.78μM and provides good practical application performance with above 96.7 ± 4.83% recovery in environmental water and soil samples. Therefore, the PGM-based amplifiable sensor for PAP proposed can accommodate these requirements of environment monitoring and has promising potential for evaluating pollutants in real environmental samples.

Glucometer Readout for Portable Detection of Heterogeneous Circulating Tumor Cells in Lung Cancer Captured on a Dual Aptamer Functionalized Wrinkled Cellulose Hydrogel Interface.

The rarity of circulating tumor cells (CTCs) poses a great challenge to their clinical application as reliable "liquid biopsy" markers for cancer diagnosis. Meanwhile, the epithelial-mesenchymal transition (EMT) led to a reduced efficiency in capturing cells with lost or downregulated epithelial cell adhesion molecule (EpCAM) expressions. In this study, we proposed an integrated, highly efficient strategy for heterogeneous CTC capture and portable detection from the blood of non-small-cell lung cancer (NSCLC) patients. First, the cellulose wrinkled hydrogel with excellent biocompatibility and high specific area was employed as the biointerface to capture heterogeneous CTCs with an improved capture efficiency in virtue of dual targeting against epithelial and mesenchymal ones. Meanwhile, the strategy of glucometer readout was introduced for the quantification of captured CTCs on the same hydrogel interface by a detection probe, Au-G-MSN-Apt, which was fabricated via entrapping glucose into the amino group functionalized mesoporous silica nanoparticle (MSN) framework sealed by l-cysteine modified gold nanoparticles (AuNPs) and then linked with dual aptamers of EpCAM and Vimentin. The number of captured CTCs on the hydrogel could be reflected according to the portable glucose meter (PGM) readings. Moreover, it was found that the captured cells maintained a higher viability on the hydrogel and could be in situ recultured without releasing from the substrate. Finally, this integrated strategy was successfully applied to inspect the correlations between the number of heterogeneous CTCs in the blood of NSCLC patients with disease stage and whether there was distant metastasis.

Glucometer-based electrochemical biosensor for determination of microRNA (let-7a) using magnetic-assisted extraction and supersandwich signal amplification.

A sensitive and portable biosensor is proposed for simple detection of microRNAs based on a supersandwich hybridization signal amplification strategy and a glucometer transducer. The presence of a target microRNA triggers the cascading hybridization chain reaction to create long supersandwich assemblies containing multiple biotin-labelled DNA probes. Then, large amounts of biotin-modified invertase signal molecules can attach to the supersandwich assemblies to generate an amplified signal for the glucometer readout. With such supersandwich format, a single target microRNA can introduce many biotin-invertase signal molecules, resulting in a one-to-multiple amplification effect. Thus, the accurate quantification of microRNAs can be achieved in a simple detection fashion without the requirement of expensive or precise instrumentation. The linear range of the biosensor for microRNA was from 0.05 to 100nM with a detection limit of 48pM. Theproposed biosensor can discriminate the target microRNA from its family members with high selectivity and can be successfully applied to the detection of target microRNA spiked in serum samples with a good recovery (96.0-108.0%). Therefore, the proposed biosensor is expected to provide more information for early and accurate cancer diagnosis.

Highly sensitive detection of extracellular vesicles on ZnO nanorods integrated microarray chips with cascade signal amplification and portable glucometer readout

Extracellular vesicle (EV) has become a type of potential biomarker for cancer diagnosis in liquid biopsy. However, the accurate detection of EVs for large-scale cancer scanning is still challenge due to the low sensitivity, high cost, and requirement of large instruments, which impedes their wide applications in clinical trials, especially in resource limited areas. Herein, we report a ZnO nanorods integrated microarray chip (ZnO-chip) for effective capture and sensitive detection of EVs. The ZnO-chip provides abundant binding sites for EVs capture. Meanwhile, the high-ordered hybridization chain reaction and non-ordered enzyme catalytic reaction are collaborated for cascade signal amplification. The oxidized product, glucose, can be read out directly by portable glucometer to realize accurate quantitation of EVs with a linear range of 1.0 × 104 to 8.4 × 107 particles/μL and a minimal detectable concentration of 3.3 × 103 particles/μL. Our approach could distinguish cancer patients from healthy individuals, proving the statistically increase of EVs in serums of cancer patients. Finally, we verify that the captured EVs can be released for downstream molecular assays by dissolving ZnO nanorods under slightly acidic condition. We believe our approach has remarkable possibility for the routine screening of cancer patients in clinical trials.

A versatile CRISPR Cas12a-based point-of-care biosensor enabling convenient glucometer readout for ultrasensitive detection of pathogen nucleic acids

Pathogen nucleic acid detection is of great significance to control the spread of diseases caused by the viruses. Nevertheless, traditional methods for nucleic acid detection such as polymerase chain reaction (PCR) and oligonucleotide microarrays require bulky instruments, which restrain their point-of-care (POC) testing application. Here, we proposed a POC method enabling sensitive detection of pathogen nucleic acids by combining the clustered regularly interspaced short palindromic repeat (CRISPR) Cas12a-based assay and personal glucometer readout (PGM). The quantification of target pathogen DNA by PGM was achieved based on pathogen DNA activates Cas12a ssDNase to cleave magnetic bead-DNA-invertase reporter probe, and separated free invertase to catalyze hydrolysis of sucrose to glucose. Without using nucleic acid amplification technology, we demonstrated here dual signal amplifications based on Cas12a and invertase-mediated catalytic reactions, making it possible to sensitively detect HIV-related DNA or SARS-CoV-2 pseudovirus with the limits of detection of 11.0 fM and 50 copies/μL, respectively. This strategy also showed excellent selectivity as well as potential applicability for detection of HIV in human serum samples or of SARS-CoV-2 in saliva samples. Therefore, our CRISPR-PGM-based dual signal amplifications detection platform might offer a great promise in POC diagnosis of pathogen nucleic acids.

Portable, quantitative, and sequential monitoring of copper ions and pyrophosphate based on a DNAzyme-Fe3O4 nanosystem and glucometer readout.

In this report, portable, quantitative, and sequential monitoring of copper ions and pyrophosphate (PPi) with a single sensor based on a DNAzyme-Fe3O4 system and glucometer readout was performed. Initially, streptavidin was functionalized on the surface of magnetic Fe3O4 spheres through glutaraldehyde. Then, an invertase-modified DNA Cu substrate was connected to the magnetic Fe3O4 spheres by a specific reaction between streptavidin and biotin. The sensing system was formed by a hybridization reaction between the Cu substrate and Cu enzyme. In the presence of Cu2+, Cu2+ will recognize the Cu DNA substrate and form an “off-on” signal switch, thereby resulting in the separation of invertase from the Fe3O4 nanospheres. PPi recognizes Cu2+ to form a Cu2+-PPi complex, resulting in an “on-off” signal switch. Under optimized conditions, linear detection ranges for Cu2+ and PPi of 0.01–5 and 0.5–10 μM, and detection limits for Cu2+ and PPi of 10 nM and 500 nM, respectively, were obtained. Good selectivity was achieved for the analysis of Cu2+ and PPi. Satisfactory results were achieved for this biosensor during the determination of Cu2+ in real tap samples and PPi in human urine samples. This verified that the sensor is portable and low cost, and can be applied to the sequential monitoring of multiple analytes with a single point-of-care biosensor.Graphical abstract

Bioinspired nanozyme enabling glucometer readout for portable monitoring of pesticide under resource-scarce environments

Pesticide residual has always been a severe environmental issue due to its adverse effects on ecosystems. The development of user-friendly program is imperative for efficient monitoring and control of pesticides with respect to environmental protection. To this end, we herein report a bioinspired nanozyme enabling portable glucometer readout for assessing pesticide residual, based on an aptamer-switching approach. Notably, Co-based metal–organic framework (Co-MOF) decorated by aptamer is built, as a signal probe, for identifying acetamiprid (as a model analyte). Comparing with the enzyme-based methods, which works in pH 6 ∼ 7, our system has high stability and DNA hybridization efficiency beyond pH 8. By introducing completive binding between acetamiprid and MOF-aptamer into glucose consumption, this method exhibits a wide linear range (1 ∼ 200 nM) with a low limit of detection (0.42 nM, corresponding to 0.093 μg kg−1 by weight), well qualified for the regular monitoring of acetamiprid residue specified by World Health Organization. With virtues of portability, sensitivity and anti-interference, the glucometer-based protocol enables us to innovatively carry out pesticide monitoring in agricultural soil, water source and foodstuffs, thereby holding promise for environmental monitoring in home-style and in-field scenarios.

Development of a "Dual Gates" Locked, Target-Triggered Nanodevice for Point-of-Care Testing with a Glucometer Readout.

Developing a facile and sensitive sensing platform is of importance for point-of-care testing (POCT). Herein, a sensitive and portable POCT platform based on "dual gates" aminated magnetic mesoporous silica nanocomposites (AMMS) bearing polydopamine (PDA)-aptamer (Apt) two-tier shells, as a novel nanodevice, is designed for target detection through a target-triggered glucose (GO) release from AMMS with personal glucometer (PGM) readout. In the absence of target, GO can be firmly captured in pores by the designed "dual gates", which would decrease the high background signal of this system and ensure the accuracy of the detection results. Upon the introduction of the target molecules under acidic conditions (pH 5.5), the subsequent PDA self-degradation and the specific Apt-target reaction can cause the departure of "dual gates" and the opening of pores to release the loaded GO molecules, which could be quantitatively monitored by a portable PGM. It has been demonstrated that such POCT platform shows high sensitivity and excellent selectivity for aflatoxin B1 (AFB1) detection, accompanied by the well-presented reproducibility and stability. Importantly, this sensing platform was further validated by assaying contaminated samples, where the obtained results were well matched with that by HPLC. Regarding the features of portability, high sensitivity, and high throughput detection, the developed platform might find wide applications in POCT.

Backfilling rolling cycle amplification with enzyme-DNA conjugates on antibody for portable electrochemical immunoassay with glucometer readout

A simple and feasible electrochemical immunosensing protocol with glucometer readout was designed for the detection of low-abundance disease-related biomarker (alpha-fetoprotein; AFP) on the basis of backfilling rolling cycle amplification (RCA) with invertase-DNA2 conjugates on the detection antibody. The assay consisted of the immunoreaction, RCA reaction, DNA2-invertase hybridization and glucose measurement. Initially, a sandwiched immunoreaction was carried out between anti-AFP capture antibody-coated microplate between nanogold-labeled pAb2 detection antibody conjugated with DNA1 primer (DNA1-AuNP-pAb2) in the presence of target ATP. Thereafter, the carried primers triggered the RCA reaction in the presence of circular DNA template, polymerase and dNTP, to produce numerous repeated oligonucleotide sequences for hybridization with many invertase-DNA2 conjugates. The carried invertase molecules accompanying the hybridization reaction hydrolyzed sucrose into glucose, thereby resulting in the amplification of the detectable signal on a handheld personal glucometer (PGM). Under optimum conditions, the developed immunoassay exhibited high sensitivity for the quantitative screening of AFP within a dynamic range of 0.1–100 ng mL−1 at a low detection limit of 0.087 ng mL−1. Other biomarkers and proteins did not interfere the signals of this system. In addition, this method was utilized to determine human serum samples containing target AFP, and received well-matched results with the referenced enzyme-linked immunosorbent assay (ELISA) method.

Oligonucleotide Cross-Linked Hydrogel for Recognition and Quantitation of MicroRNAs Based on a Portable Glucometer Readout.

A novel sensing platform for recognition and quantification of target microRNAs (miRNAs) was developed by combining an amylase-trapped DNA hydrogel, multicomponent nucleic acid enzymes (MNAzymes), and a portable glucometer (PGM) readout. First, the amylase was encapsulated inside the DNA hydrogel and physically separated from its substrate of amylose, which was in a solution outside the hydrogel. After addition of the target miRNA, the activity of the MNAzyme was restored, which cuts off the substrate linker strand. The active MNAzyme can catalytically act upon multiple substrate strands through diffusion, leading to the collapse of the hydrogel and the release of amylase, which catalyzes the hydrolysis of amylose to produce a large amount of glucose and generate a high PGM signal. The smart usage of the PGM enables simple portable detection of miR-21, with a detection limit as low as 0.325 fmol. Additionally, through the simple rational design of the target-binding sensor arms, the amylase-trapped DNA hydrogel sensing platform was successfully applied in the detection of multiple endogenous miRNAs (including miR-21, miR-335, miR-155, and miR-122) extracted from HeLa cells, HepG2 cells, MCF-7 cells, and L02 cells.

Sensitive electrochemical detection of microRNA-21 based on propylamine-functionalized mesoporous silica with glucometer readout.

A new homogeneous electrochemical sensing system was developed for sensitive detection of microRNA-21 (miRNA-21) based on target-induced glucose release from propylamine-functionalized mesoporous silica nanoparticle (MSN) with glucometer readout. Glucose molecules (as the signal tracers) were initially gated into the pores through the interaction of the negatively charged anchor DNA with the aminated MSN. Upon addition of target miRNA, the analyte competitively hybridized with anchor DNA to form the RNA-DNA duplex, thus resulting in detachment of anchor DNA from the MSN accompanying the pore opening. The loaded glucose molecules released out from the pores because of concentration gradients, which could be detected by using a portable personal glucometer (PGM). Experimental results indicated that the PGM signal increased with the increasing miRNA level, and exhibited a good linear dependence on the miRNA-21 concentration from 50pM to 5.0nM with a detection limit of 19pM under optimum conditions. Additionally, multifunctional mesoporous silica nanoparticles also showed good stability and favorable selectivity, and satisfactory accuracy for the miRNA detection in cell lysates with quantitative real-time polymerase chain reaction (qRT-PCR). Such good analytical performance endows it as a promising scheme for the efficient and convenient detection of miRNA in clinical diagnosis and therapy. Graphical abstract An electrochemical sensing system is designed for detection of microRNA-21 based on target-induced glucose release from propylamine-functionalized mesoporous silica nanoparticle with glucometer readout.

Graphene oxide-gated mesoporous silica nanocontainers using aptamers for arsenite detection with glucometer readout

A newly portable detection sensing platform based on a graphene oxide (GO)-gated mesoporous silica nanocontainer (MSN) was designed for arsenite detection through the target-responsive release of glucose from the MSN with a glucometer readout. To construct such a biosensing system, the arsenite aptamer was initially conjugated covalently onto the mesoporous silica nanoparticles through the epoxy-amino reaction. Thereafter, the indicators (glucose molecules) were gated into the pores by using graphene oxide nanosheets, on the basis of π-stacking interactions between the nucleobases and graphene. Upon target arsenite introduction, graphene oxide was displaced from the MSN thanks to a specific reaction between the analyte and the aptamer, thus resulting in the opening of the pores to release the loaded glucose molecules, which could be determined quantitatively by using a portable personal glucometer (PGM). Based on the different affinities between graphene and the analyte for the labeled aptamer on the MSN, the amount of released glucose molecules from the pores increased with the increasing arsentite concentrations. Under optimal conditions, the GO-gated aptasensing system exhibited good PGM responses relative to arsenite concentrations within the dynamic working range of 0.01-100 ng mL-1 (ppb) at a detection limit of 2.3 pg mL-1 (ppt). The coefficients of variation (CVs) for the reproducibility of intra-assay and inter-assay were below 9.1% and 11.6%, respectively. In addition, the methodology also displayed high specificity and selectivity towards target arsenite against other ions, and was applicable for monitoring arsenite in water samples, giving well-matched results in accordance with the referenced ICP-MS.

Integrated immunochromatographic strip with glucometer readout for rapid quantification of phosphorylated proteins

A new technology to quantify phospho-p5315 by converting its content to the amount of glucose which is detectable by a glucometer was developed. An immunochromatographic test strip (ITS) was used as a disposable platform, where primary antibody (Ab1)-modified Fe3O4 magnetic nanoparticles (Fe3O4-Ab1) were settled on the test zone to capture both the target phospho-p5315 and the detection antibody (Ab2)-glucose encapsulating liposome (GEL) conjugate. The measurement was based on the release and subsequent detection of glucose from Ab2-GEL using a glucose meter (GM). The amount of glucose is proportional to the phospho-p5315 concentration from 0.1 to 50 ng mL−1, the limit of detection is 50 pg mL−1 (3S/N). The high sensitivity was a result of the huge number of glucose encapsulated in the liposome. Taking the advantage of low cost, widespread availability and portability of the test trip, together with the personal GM, the presented approach can be easily used to detect other disease biomarkers in medical diagnostics and environmental monitoring.

Bioresponsive controlled glucose release from TiO2 nanotube arrays: a simple and portable biosensing system for cocaine with a glucometer readout

Herein, we design a simple and portable biosensing platform for the quantitative detection of cocaine based on target-triggered glucose release from a TiO2 nanotube array (TiNTA) with a glucometer readout.

Liposome-encoded magnetic beads initiated by padlock exponential rolling circle amplification for portable and accurate quantification of microRNAs.

Development of reliable and affordable quantitative methods for miRNAs with high specificity and sensitivity is a central challenge to make miRNA testing a routine part of medical care with respect to cancer. Herein, we propose a strategy for glucoamylase-encapsulated liposome-encoded magnetic beads initiated by padlock exponential rolling circle amplification (P-ERCA) for portable and accurate quantification of miRNA by using a glucometer readout.

Invertase-labeling gold-dendrimer for in situ amplified detection mercury(II) with glucometer readout and thymine-Hg(2+)-thymine coordination chemistry.

A simple, low-cost transducer with glucometer readout was designed for sensitive detection of mercury(II) (Hg(2+)), coupling with thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and invertase-functionalized gold-dendrimer nanospheres for the signal amplification. Initially, nanogold-encapsulated poly(amidoamine) dendrimers (Au DENs) were synthesized by in-situ reduction of gold(III). Thereafter, the as-prepared Au DENs were utilized for the labeling of invertase and T-rich signal DNA probe. In the presence of target Hg(2+), the functionalized Au DENs were conjugated to capture DNA probe-modified electrode via T-Hg(2+)-T coordination chemistry. Accompanying the Au DENs, the labeled invertase could hydrolyze sucrose into glucose, which could be quantitatively monitored by an external personal glucometer (PGM). The PGM signal increased with the increasing target Hg(2+) in the sample. Under the optimal conditions, our designed sensing platform exhibited good PGM responses toward target Hg(2+), and allowed the detection of Hg(2+) at a concentration as low as 4.2 pM. This sensing system also displayed remarkable specificity relative to target Hg(2+) against other competing ions, and could be applied for reliable monitoring of spiked Hg(2+) into the environmental water samples with satisfactory results. With the advantages of cost-effectiveness, simplicity, portability, and convenience, our strategy provides a tremendous potential to be a promising candidate for point-of-use monitoring of non-glucose targets by the public.

Glucose encapsulating liposome for signal amplification for quantitative detection of biomarkers with glucometer readout.

A new technology was developed to quantitatively detect a broad range of disease biomarkers and proven to be portable, economical, and conveniently accessible. Measurements were performed based on releasing encapsulated glucose from antibody-tagged liposomes and subsequently detecting the released glucose using a commercial personal glucose meter (GM). The innovative aspect of this approach lies in the quantification of target biomarkers through the detection of glucose, thus expanding the applicability of the GM by broadening the range of target biomarkers instead of detecting only one analyte, glucose. Because of the bilayer membrane of liposomes, which can accommodate tens of thousands of glucose molecules, the sensitivity was greatly enhanced by using glucose encapsulating liposomes as a signal output and an amplifier. Here, the model analyte, protein 53 phosphorylated on Serine 15 (phospho-p53(15)), was captured by primary antibodies bound on magnetic Fe3O4 nanoparticles and then recognized by reporting antibodies conjugated to glucose encapsulating liposomes. Finally, the target phospho-p53(15) was detected by lysing the bound liposomes to release the encapsulated glucose (4 × 10(5) glucose molecules per liposome), which is detected with the GM. This approach was demonstrated to be a universal technology that can be easily produced to quantify a wide variety of biomarkers in medical diagnostics, food safety, public health, and environmental monitoring. In the near future, it is expected that these sensors, in combination with a portable GM, can be used in many fields such as physicians' laboratories, hospitals and the common household.

Gold nanocluster-encapsulated glucoamylase as a biolabel for sensitive detection of thrombin with glucometer readout

This article reports on a sensitive aptamer-based assay for thrombin. The assay includes the following steps: (a) a first thrombin-specific aptamer (P1) was immobilized on the surface of the wells of a microtiter plate via biotin-streptavidin interaction; (b) gold nanoclusters (GNCs) were used to cover the enzyme glucoamylase via a reverse micelle method; (c) the GNCs were then coated with the second aptamer (P2) via thiol chemistry; (d) addition of a solution containing thrombin to the well, and (e) subsequent addition of amylopectin. The glucoamylase in the GNC label catalytically hydrolyzes the amylopectin to form glucose which then is quantified with a glucometer. Under optimal conditions, the signal for glucose increases with the concentration of thrombin in range from 0.05 to 100 nM, and the detection limit is as low as 10 pM. The assay has a good repeatability and displays an intermediate precision of down to 11 %. Nonspecific adsorption was not observed in a series of analyses. The method was applied to the determination of thrombin in spiked serum samples, and the recoveries ranged from 94 to 110 %. The method is assumed to have a wide scope in that it may be extended to numerous other analytes for which appropriate aptamers are available.

Target-induced DNAzyme Cleavage Accompanying Bioactive Enzymatic Assembly with Glucometer Readout for Quantitative Monitoring of Lead Ion

Abstract Target-induced DNAzyme cleavage is designed for sensitive monitoring of lead ion with glucometer readout, coupling with an additional single-strand DNA accompanying glucoamylase assembly.

A portable and quantitative enzyme immunoassay of neuron-specific enolase with a glucometer readout

A portable and quantitative enzyme immunoassay with a glucometer readout was developed for the sensitive monitoring of neuron-specific enolase (NSE, as a model analyte) in a high-binding polystyrene 96-well microtiter plate (MTP), conjugated with monoclonal mouse anti-human NSE antibody (mAb1).