Ultrasensitive Detection Research Articles

Ultrasensitive and Rapid Circulating Tumor DNA Liquid Biopsy Using Surface-Confined Gene Amplification on Dispersible Magnetic Nano-Electrodes.

Circulating tumor DNA (ctDNA) detection has been acknowledged as a promising liquid biopsy approach for cancer diagnosis, with various ctDNA assays used for early detection and treatment monitoring. Dispersible magnetic nanoparticle-based electrochemical detection methods have been proposed as promising candidates for ctDNA detection based on the detection performance and features of the platform material. This study proposes a nanoparticle surface-localized genetic amplification approach by integrating Fe3O4-Au core-shell nanoparticles into polymerase chain reactions (PCR). These highly dispersible and magnetically responsive superparamagnetic nanoparticles act as nano-electrodes that amplify and accumulate target ctDNA in situ on the nanoparticle surface upon PCR amplification. These nanoparticles are subsequently captured and subjected to repetitive electrochemical measurements to induce reconfiguration-mediated signal amplification for ultrasensitive (∼3 aM) and rapid (∼7 min) metastatic breast cancer ctDNA detection in vitro. The detection platform can also detect metastatic biomarkers from in vivo samples, highlighting the potential for clinical applications and further expansion to rapid and ultrasensitive multiplex detection of various cancers.

Near-infrared light-driven lab-on-paper cathodic photoelectrochemical aptasensing for di(2-ethylhexyl)phthalate based on AgInS2/Cu2O/FeOOH photocathode

Di(2-ethylhexyl)phthalate (DEHP) is commonly released from plastics in aqueous environment, which can disrupt endocrine system and cause adverse effects on public health. There is a pressing need to highly sensitive detect DEHP. Herein, a near-infrared (NIR) light-driven lab-on-paper cathodic photoelectrochemical aptasensing platform integrated with AgInS2/Cu2O/FeOOH photocathode and “Y”-like ternary conjugated DNA nanostructure-mediated “ON-OFF” catalytic switching of hemin monomer-to-dimer was established for ultrasensitive DEHP detection. Profiting from the collaborative roles of the effective photosensitization of NIR-response AgInS2 and the fast hole extraction of FeOOH, the NIR light-activated AgInS2/Cu2O/FeOOH photocathode generated a markedly enhanced photocathodic signal. The dual hemin-labelled “Y”-like ternary conjugated DNA nanostructures made the hemin monomers separated in space and they maintained highly active to catalyze in situ generation of electron acceptors (O2). The hemin monomers were relocated in close proximity with the help of target-induced allosteric change of DNA nanostructures, which could spontaneously dimerize into catalytically inactive hemin dimers and fail to mediate electron acceptors generation, resulting in a decreased photocathodic signal. Therefore, the ultrasensitive DEHP detection was realized with a linear response range of 1 pM–500 nM and a detection limit of 0.39 pM. This work rendered a promising prototype to construct powerful paper-based photocathodic aptasensing system for sensitive and accurate screening of DEHP in aqueous environment.

Target-Induced Dual-Wing Photocurrent Response Based on Au@CdSe@Au Nanoparticles for Ultrasensitive Detection of Cholesterol

Target-Induced Dual-Wing Photocurrent Response Based on Au@CdSe@Au Nanoparticles for Ultrasensitive Detection of Cholesterol

Ultra-Sensitive Detection of the SARS-CoV-2 Nucleocapsid Protein via a Clustered Regularly Interspaced Short Palindromic Repeat/Cas12a-Mediated Immunoassay.

Tracking trace protein analytes in precision diagnostics is an ongoing challenge. Here, we developed an ultrasensitive detection method for the detection of SARS-CoV-2 nucleocapsid (N) protein by combining enzyme-linked immunosorbent assay (ELISA) with the clustered regularly interspaced short palindromic repeat/CRISPR-associated protein (CRISPR/Cas) system. First, the SARS-CoV-2 N protein bound by the capture antibody adsorbed on the well plate was sequentially coupled with the primary antibody, biotinylated secondary antibody, and streptavidin (SA), followed by biotin primer binding to SA. Subsequently, rolling circle amplification was initiated to generate ssDNA strands, which were targeted by CRISPR/Cas12a to cleave the FAM-ssDNA-BHQ1 probe in trans to generate fluorescence signals. We observed a linear relationship between fluorescence intensity and the logarithm of N protein concentration ranging from 3 fg/mL to 3 × 107 fg/mL. The limit of detection (LOD) was 1 fg/mL, with approximately nine molecules in 1 μL of the sample. This detection sensitivity was 4 orders magnitude higher than that of commercially available ELISA kits (LOD: 5.7 × 104 fg/mL). This method was highly specific and sensitive and could accurately detect SARS-CoV-2 pseudovirus and clinical samples, providing a new approach for ultrasensitive immunoassay of protein biomarkers.

“Green” one-pot synthesis of hemin complex with excellent peroxidase activity: Efficient enhanced chemiluminescence immunosensor for ultrasensitive detection of ochratoxin A

Compared with natural enzymes, nanozymes have the advantages of easy preparation, low cost and high stability. With the booming development of nanozymes, scientists have further defined them as “nanomaterials with enzyme-like properties”. Here, on the one hand, ZIF-L has the characteristics of simple preparation, good stability and large specific surface area. Meanwhile, the array structure of Zn2+ and imidazole in the ZIF-L can replace the amino acids precisely located in the natural enzymes, thus mimicking the microenvironment of the natural peroxidase. On the other hand, based on the chemical similarity of hemin to natural heme, we encapsulated hemin into the ZIF-L backbone by a straightforward “green” one-pot technique. According to the symbiotic stability-enhancing effect, the encapsulated biomolecules can make the ZIF-L matrix more stable while the ZIF-L backbone protects the enzyme from denaturation. Based on this, ZIF-L-Hemin composites with excellent peroxidase properties was successfully prepared. Using ZIF-L-Hemin composites, we constructed a flow-injection chemiluminescence immunoassay for the quick and ultrasensitive detection of ochratoxin A (OTA) in food. The experimental results showed that the detection range of OTA was 0.0015 ∼ 1500 ng mL−1, and the limit of detection (LOD) was 0.47 pg mL−1 (S/N = 3). The OTA analysis of wheat, corn and feed samples showed that the recoveries ranged from 80.83 % to 115.54 %, which successfully demonstrated the usability and potential applications of immunosensor.

Dual-ligand lanthanide metal-organic framework based ratiometric fluorescent platform for visual monitoring of aminoglycoside residues in food samples

Herein, a dual-emission Eu metal-organic framework (Eu-MOF) is prepared and used as the ratiometric fluorescence probe for ultrasensitive detection of aminoglycoside antibiotics (AGs). Due to the strong hydrogen bond interactions between AGs and Eu-MOF, the blue emission is enhanced while the red emission has little fluctuation in Eu-MOF with the addition of AGs, thus a good linear relationship with the logarithm of AGs concentrations from 0.001 to 100 μg/mL can be established for quantitative analysis. Good sensitivity with the detection limit of 0.33 ng/mL for apramycin, 0.32 ng/mL for amikacin and 0.30 ng/mL for kanamycin is achieved. The proposed assay demonstrates good selectivity and applicability for determination of AGs in real milk and honey samples. The Eu-MOF materials are further fabricated as fluorescent test papers for facile visual detection. The as-established ratio fluorescence platform offers a portable and economical way for rapid monitoring AGs residues in complex food samples.

Accelerated peroxidase-like activity of ultrathin amine-tagged bimetallic MOF-74 nanozyme for construction of versatile bioassays from small molecules to enzymes and bacteria

The exquisite design of nanostructures for enzyme-biocatalyzed active sites mimicking has become a prospective method to significantly boost biocatalytic properties, which is profitable to response amplification for bioanalysis scenarios. Metal-organic frameworks (MOFs) with customizable compositions, diverse microstructures and open catalytic sites are considered to deal with challenges in conventional materials of unfriendly microenvironment and inexact coordination. Herein, by combining a metal doping and post-synthetic modification approach, amine-tagged Fe-Ni bimetallic MOF-74 nanozyme (FeNi-MOF-74-NH2) with ultrathin structure and improved peroxidase-mimicking bioactivity is synthesized through a layered double hydroxide (LDH) directed method. The boosted biocatalytic property largely benefits from the synergistic effects of Fe-Ni species, attributing to the dual mechanism (electron transfer and generation of hydroxyl radicals). On the basis of the enhanced enzyme-mimicking property and accessible amino functionalization of FeNi-MOF-74-NH2, versatile applications were carried out for the ultrasensitive detection of analytes from bioactive small molecules (H2O2 and ascorbic acid), biomacromolecules (alkaline phosphatase, ascorbic acid oxidase, and α-glucosidase), and pathogenic bacteria (Staphylococcus aureus). The nanozyme-based biosensing platform without complex enzymatic techniques serves as a proof-of-concept to facilitate the application of MOF nanozymes in biochemical analysis, clinical diagnosis, and biomedical research.

A surface-enhanced Raman scattering and colorimetric dual-mode aptasensor for ultrasensitive detection of kanamycin based on DNA hydrogel network fishing the MIL-101@AuNP nanohybrids

It is of utmost importance to develop a simple, sensitive, and dependable technique for detecting kanamycin (Kana). Utilizing MIL-101@AuNP nanohybrids and DNA hydrogel, we devised a dual-mode aptasensor for Kana detection employing surface-enhanced Raman spectroscopy (SERS) and a colorimetric method. The MIL-101@AuNP nanohybrids displayed excellent peroxidase-like and SERS activities. In the existence of Kana, the aptamer specifically bound to Kana, releasing complementary DNA strands (cDNA). Employing free cDNA as a primer, circular DNA templates were generated for the rolling circle amplification (RCA) reaction. DNA hydrogel network formed via the physical entanglement and hybridization of two ultralong single-strand DNA chains from the double RCA-generated, capturing MIL-101@AuNP nanohybrids, thereby enhancing the SERS signal of the DNA hydrogel. Concurrently, the absorbance signal of 3,3′,5,5′-tetramethylbenzidine (TMB)-H2O2 system catalyzed by unfished MIL-101@AuNP was weakened. The dual-mode aptasensor, employing SERS and colorimetric methods, quantitatively detected Kana within concentration ranges of 0.003–300 ng/mL and 0.03–100 ng/mL, respectively, with detection limits (LOD) of 0.001 ng/mL and 0.018 ng/mL, respectively. Importantly, this method was applied to detect Kana-spiked milk samples, yielding satisfactory spiked recoveries. The proposed approach combines the advantages of SERS and colorimetric methods, offering high sensitivity, reliability, and broad applicability, thereby presenting a novel thinking for constructing multimode sensing platforms.

Metal-Organic Frameworks/Heterojunction Structures for Surface-Enhanced Raman Scattering with Enhanced Sensitivity and Tailorability.

Metal-organic frameworks (MOFs), which are composed of crystalline microporous materials with metal ions, have gained considerable interest as promising substrate materials for surface-enhanced Raman scattering (SERS) detection via charge transfer. Research on MOF-based SERS substrates has advanced rapidly because of the MOFs' excellent structural tunability, functionalizable pore interiors, and ultrahigh surface-to-volume ratios. Compared with traditional noble metal SERS plasmons, MOFs exhibit better biocompatibility, ease of operation, and tailorability. However, MOFs cannot produce a sufficient limit of detection (LOD) for ultrasensitive detection, and therefore, developing an ultrasensitive MOF-based SERS substrate is imperative. To the best of our knowledge, this is the first study to develop an MOFs/heterojunction structure as an SERS enhancing material. We report an in situ ZIF-67/Co(OH)2 heterojunction-based nanocellulose paper (nanopaper) plate (in situ ZIF-67 nanoplate) as a device with an LOD of 0.98 nmol/L for Rhodamine 6G and a Raman enhancement of 1.43 × 107, which is 100 times better than that of the pure ZIF-67-based SERS substrate. Further, we extend this structure to other types of MOFs and develop an in situ HKUST-1 nanoplate (with HKUST-1/Cu(OH)2). In addition, we demonstrate that the formation of heterojunctions facilitates efficient photoinduced charge transfer for SERS detection by applying the Mx(OH)y-assisted (where M = Co, Cu, or other metals) MOFs/heterojunction structure. Finally, we successfully demonstrate the application of medicine screening on our nanoplates, specifically for omeprazole. The nanoplates we developed still maintain the tailorability of MOFs and perform high anti-interference ability. Our approach provides customizing options for MOF-based SERS detection, catering to diverse possibilities in future research and applications.

Ultrasensitive and Highly Selective Detection of Staphylococcus aureus at the Single-Cell Level Using Bacteria-Imprinted Polymer and Vancomycin-Conjugated MnO2 Nanozyme.

Pathogenic bacterial infections, even at extremely low concentrations, pose significant threats to human health. However, the challenge persists in achieving high-sensitivity bacterial detection, particularly in complex samples. Herein, we present a novel sandwich-type electrochemical sensor utilizing bacteria-imprinted polymer (BIP) coupled with vancomycin-conjugated MnO2 nanozyme (Van@BSA-MnO2) for the ultrasensitive detection of pathogenic bacteria, exemplified by Staphylococcus aureus (S. aureus). The BIP, in situ prepared on the electrode surface, acts as a highly specific capture probe by replicating the surface features of S. aureus. Vancomycin (Van), known for its affinity to bacterial cell walls, is conjugated with a Bovine serum albumin (BSA)-templated MnO2 nanozyme through EDC/NHS chemistry. The resulting Van@BSA-MnO2 complex, serving as a detection probe, provides an efficient catalytic platform for signal amplification. Upon binding with the captured S. aureus, the Van@BSA-MnO2 complex catalyzes a substrate reaction, generating a current signal proportional to the target bacterial concentration. The sensor displays remarkable sensitivity, capable of detecting a single bacterial cell in a phosphate buffer solution. Even in complex milk matrices, it maintains outstanding performance, identifying S. aureus at concentrations as low as 10 CFU mL-1 without requiring intricate sample pretreatment. Moreover, the sensor demonstrates excellent selectivity, particularly in distinguishing target S. aureus from interfering bacteria of the same genus at concentrations 100-fold higher. This innovative method, employing entirely synthetic materials, provides a versatile and low-cost detection platform for Gram-positive bacteria. In comparison to existing nanozyme-based bacterial sensors with biological recognition materials, our assay offers distinct advantages, including enhanced sensitivity, ease of preparation, and cost-effectiveness, thereby holding significant promise for applications in food safety and environmental monitoring.

Synergetic Electromagnetic Enhancement and Charger Transfer in Boat-Like Au/PbS/Au Nanohybrids with Increased SERS Activity for Ultrasensitive Molecular Detection

Synergetic Electromagnetic Enhancement and Charger Transfer in Boat-Like Au/PbS/Au Nanohybrids with Increased SERS Activity for Ultrasensitive Molecular Detection

A quadratic isothermal amplification fluorescent biosensor without intermediate purification for ultrasensitive detection of circulating tumor DNA.

Circulating tumor DNA (ctDNA) is an auspicious tumor biomarker released into the bloodstream by tumor cells, offering abundant information concerning cancer genes. It plays a crucial role in the early diagnosis of cancer. However, due to extremely low levels in body fluids, achieving a simple, sensitive, and highly specific detection of ctDNA remains challenging. Here, we constructed a purification-free fluorescence biosensor based on quadratic amplification of ctDNA by combining nicking enzyme mediated amplification (NEMA) and catalytic hairpin assembly (CHA) reactions. After double isothermal amplification, this biosensor achieved an impressive signal amplification of nearly 107-fold, enabling it to detect ctDNA with ultra-sensitivity. And the detection limit of this biosensor is as low as 2 aM. In addition, we explored the influence of human serum on the performance of the biosensor and found that it showed favorable sensitivity in the presence of serum. This biosensor eliminates the need for an intermediate purification step, resulting in enhanced sensitivity and convenience. Thus, our purification-free fluorescent biosensor exhibits ultra-high sensitivity when compared to other biosensors and has the potential to serve as an effective diagnostic tool for early detection of cancer.

Coupling Multidimensional Chromatography with Plasmonic Sensing: An Exploration of Electrochemical SERS as a Detection Modality for 2D-LC

Complex mixtures which may contain hundreds, if not thousands, of unique compounds pose an analytical challenge for complete and detailed analyses. For example, green tea is a well-known complex substance requiring advanced separation techniques and ultrasensitive detection methods for full characterization. Separation and identification of components in green tea help gauge tea quality, as green tea is one of the most consumed beverages in the world. In this work, the coupling of two-dimensional liquid chromatography (2D-LC) and electrochemical surface-enhanced Raman spectroscopy (EC-SERS) was explored for the first time to analyze compounds in green tea. 2D-LC offers enhanced separation compared to conventional HPLC systems due to the second dimension of separation. EC-SERS was used as an offline detection modality and qualitative tool to help identify the compounds in green tea fractions collected from the second dimension separation. 2D-LC and EC-SERS are coupled in this work for the first time and offer a pathway forward for sensitive and selective separation and identification of components in complex mixtures.

Gold nanostructure-enhanced immunosensing: ultra-sensitive detection of VEGF tumor marker for early disease diagnosis

We present an advanced electrochemical immunosensor designed to detect the vascular endothelial growth factor (VEGF) precisely. The sensor is constructed on a modified porous gold electrode through a fabrication process involving the deposition of silver and gold on an FTO substrate. Employing thermal annealing and a de-alloying process, the silver is eliminated from the electrode, producing a reproducible porous gold substrate. Utilizing a well-defined protocol, we immobilize the heavy-chain (VHH) antibody against VEGF on the gold substrate, facilitating VEGF detection through various electrochemical methods. Remarkably, this immunosensor performs well, featuring an impressive detection limit of 0.05 pg/mL and an extensive linear range from 0.1 pg/mL to 0.1 µg/mL. This emphasizes it’s to measure biomarkers across a wide concentration spectrum precisely. The robust fabrication methodology in this research underscores its potential for widespread application, offering enhanced precision, reproducibility, and remarkable detection capabilities for the developed immunosensor.

Electrochemical cytosensor utilizing tetrahedral DNA/bimetallic AuPd holothurian-shaped nanoparticles for ultrasensitive non-destructive detection of circulating tumor cells.

As a real-time fluid biopsy method, the detection of circulating tumor cells (CTCs) provides important information for the early diagnosis, precise treatment, and prognosis of cancer. However, the low density of CTCs in the peripheral blood hampers their capture and detection with high sensitivity and selectivity using currently available methods. Hence, we designed a sandwich-type electrochemical aptasensor that utilizes holothurian-shaped AuPd nanoparticles (AuPd HSs), tetrahedral DNA nanostructures (TDNs), and CuPdPt nanowire networks (NWs) interwoven with a graphdiyne (GDY) sheet for ultrasensitive non-destructive detection of MCF-7 breast cancer cells. CuPdPt NW-GDY effectively enhanced the electron transfer rate and coupled with the loaded TDNs. The TDNs could capture MCF-7 cells with precision and firmness, and the resulting composite complex was combined with AuPd HSs to form a sandwich-type structure. This novel aptasensor showed a linear range between 10 and 106 cells mL-1 and an ultralow detection limit of 7 cells mL-1. The specificity, stability, and repeatability of the measurements were successfully verified. Moreover, we used benzonase nuclease to achieve non-destructive recovery of cells for further clinical studies. According to the results, our aptasensor was more sensitive measuring the number of CTCs than other approaches because of the employment of TDNs, CuPdPt NW-GDY, and AuPd HSs. We designed a reliable sensor system for the detection of CTCs in the peripheral blood, which could serve as a new approach for cancer diagnosis at an early stage.

Ultrasensitive detection of chlortetracycline in animal-origin food using molecularly imprinted electrochemical sensor based on SnS2/ZnCo-MOF and AuNPs

The chlortetracycline (CTC) residue in food poses a threat to human health. Therefore, developing sensitive, convenient and selective analytical methods for CTC detection is crucial. This study innovatively uses tin disulfide/bimetallic organic framework (SnS2/ZnCo-MOF) nanocomposites in conjunction with gold nanoparticles (AuNPs) to co-modify a glassy carbon electrode (GCE). Further, a molecularly imprinted polymer (MIP)-based electrochemical sensing platform Au-MIP/SnS2/ZnCo-MOF/Au/GCE (AZG) was fabricated for selective CTC detection. SnS2/ZnCo-MOF enhanced the stability and surface area of the AZG sensor. The presence of AuNPs facilitated electron transport between the probe and the electrode across the insulating MIP layer. The fixation of AuNPs and MIP via electropolymerization enhanced the selective recognition of this sensor and amplified its output signal. The AZG sensor demonstrated a wide linear detection range (0.1–100 μM), low detection limit (0.072 nM), and high sensitivity (0.830 μA μM−1). It has been used for detecting CTC in animal-origin food with good recovery (96.08%–104.60%).

A Ce2MgMoO6 double perovskite decorated on a functionalized carbon nanofiber nanocomposite for quantification of ciprofloxacin in milk and honey samples: Density functional theory interpretation

In this study, a novel Ce2MgMoO6/CNFs (cerium magnesium molybdite double perovskite decorated on carbon nanofibers) nanocomposite was developed for selective and ultra-sensitive detection of ciprofloxacin (CFX). Physical characterization and analytical techniques were used to explore the morphology, structure, and electrocatalytic characteristics of the Ce2MgMoO6/CNFs nanocomposite. The sensor has a wide linear range (0.005–7.71 μM and 9.75–77.71 μM), a low limit of detection (0.012 μM), high sensitivity (0.807 μA μM−1 cm−2 nM), remarkable repeatability, and an appreciable storage stability. Here, we used density functional theory to investigate CFX and oxidized CFX as well as the locations of the energy levels and electron transfer sites. Furthermore, the Ce2MgMoO6/CNFs-modified electrode was successfully tested in food samples (milk and honey), indicating an acceptable response with a recovery percentage and relative standard deviation of less than 4%, which is comparable to that of GC-MS. Finally, the developed sensor exhibited high selectivity and stability for CFX detection.

PNA-Functionalized, Silica Nanowires-Filled Glass Microtube for Ultrasensitive and Label-Free Detection of miRNA-21.

MicroRNAs (miRNAs) are endogenous and noncoding single-stranded RNA molecules with a length of approximately 18-25 nucleotides, which play an undeniable role in early cancer screening. Therefore, it is very important to develop an ultrasensitive and highly specific method for detecting miRNAs. Here, we present a bottom-up assembly approach for modifying glass microtubes with silica nanowires (SiNWs) and develop a label-free sensing platform for miRNA-21 detection. The three-dimensional (3D) networks formed by SiNWs make them abundant and highly accessible sites for binding with peptide nucleic acid (PNA). As a receptor, PNA has no phosphate groups and exhibits an overall electrically neutral state, resulting in a relatively small repulsion between PNA and RNA, which can improve the hybridization efficiency. The SiNWs-filled glass microtube (SiNWs@GMT) sensor enables ultrasensitive, label-free detection of miRNA-21 with a detection limit as low as 1 aM at a detection range of 1 aM-100 nM. Noteworthy, the sensor can still detect miRNA-21 in the range of 102-108 fM in complex solutions containing 1000-fold homologous interference of miRNAs. The high anti-interference performance of the sensor enables it to specifically recognize target miRNA-21 in the presence of other miRNAs and distinguish 1-, 3-mismatch nucleotide sequences. Significantly, the sensor platform is able to detect miRNA-21 in the lysate of breast cancer cell lines (e.g., MCF-7 cells and MDA-MB-231 cells), indicating that it has good potential in the screening of early breast cancers.

Multi-walled carbon Nanotube wrapped rare earth tungstate nanosheet composites for selective and rapid detection of sulfadiazine

Multi-walled Carbon Nanotube Wrapped Rare earth Tungstate Nanosheet Composites are developed for the ultrasensitive and selective electrochemical detection of sulfa drug, sulfadiazine (SAN) as they exhibit high levels of toxicity towards public health and ecosystem. Here, we synthesized Gadolinium tungstate decorated with multi-walled carbon nanotubes (Gd2WO6/MWCNT) though hydrothermal processing and characterized by XRD, SEM, EDX, TEM, and EIS measurement to investigate the phase purity, morphology, and interfacial property. Gd2WO6 is a double perovskite that has high oxygen surface exchange kinetics and the MWCNT possesses high catalytic capability and a larger surface area contributes to the efficient sensing ability. The Gd2WO6/MWCNT possessed a great electrical conductivity owing to the synergism between the Gd2WO6 and MWCNT. The synergistic effect increases the surface area and ionic and electrical conductivity which increases the current response of SAN. Under optimum conditions, the Gd2WO6/MWCNT/GCE displays a broad linear of 0.01 – 671 µM and a LOD level of 2 nM (S/N ratio: 3) with a sensitivity of 0.371 µA µM cm-1. The analytical applicability of the proposed electrode modifier leads to a promising sensor for SAN detection in human urine and water samples with appreciable results.

Self-assembled sensing interface based on specific aptamer functionalized Ti3C2 MXene for ultrasensitive antibiotic detection in milk

A self-assembled sensing interface based on Ti3C2 MXene functionalized by aptamer had been successfully constructed in this work, which fully utilizes the electrical properties of Ti3C2 MXene and the specific recognition ability of the aptamer. Subsequently, we studied the performance of the sensing interface using two antibiotic residues as examples. Under the optimal conditions, the sensing interface showed a linear range of 100 fM–1 μM and a limit of detection of 1 fM to detect kanamycin and tetracycline, furthermore the recovery rates were 97.15%–103.00% and 99.559%–106.36%, respectively. In addition, the sensing behaviors of aptamers specific recognition of target can be perceived by the interface, thereby exhibiting different electrical responses. Therefore, the self-assembled sensing interface not only provided a new avenue for the development of ultrasensitive technology in the food analysis field but also for investigating aptamer configurational transformations.