Imprinting Layer Research Articles

Novel graphene electrochemical transistors incorporating zirconia inorganic molecular imprinted layer：Design, construction and application for highly sensitive and selective detection of acetaminophen

Owing to their intrinsic amplifying effect together with chemical stability, graphene electrochemical transistor sensors (GECTs) are gaining momentum for sensing applications. However, the surface of GECTs for different detection substances must be modified with different recognition molecules, which was cumbersome and lack a universal method. Molecularly imprinted polymer (MIP) is a kind of polymer with specific recognition function for given molecules. Here, MIP and GECTs were combined to effectively solve the problem of weak selectivity of GECTs, and achieve the high sensitivity and selectivity of MIP-GECTs equipment in detecting acetaminophen (AP) in complex urine environment. A novel molecular imprinting sensor based on Au nanoparticles modified zirconia (ZrO2) inorganic molecular imprinting membrane on reduced graphene oxide (ZrO2-MIP-Au/rGO) was proposed. ZrO2-MIP-Au/rGO was synthesized by one-step electropolymerization using AP as template, ZrO2 precursor as the functional monomer. The –OH group on ZrO2 and the –OH/–CONH– group on AP were easily bonded by hydrogen bonding to form a MIP layer on the surface, which allows the sensor to have a large number of imprinted cavities for AP specific adsorption. As a proof of method, the GECTs based on ZrO2-MIP-Au/rGO functional gate electrode has the characteristics of wide linear range (0.1 nM-4 mM), low detection limit (0.1 nM) and high selectivity for AP detection. These achievements highlight the introduction of specific and selective MIP to GECTs with unique amplification function, which could effectively solve the problem of selectivity of GECTs in complex environments, suggesting the potential of MIP-GECTs in real-time diagnosis.

Continuous-imprinted-layer nanofiber membrane with MXene-based precise-designed nanocages for high-accuracy recognition and separation of shikimic acid

Ti3C2Tx (MXene) has attracted extensive attention from scholars at home and abroad due to its rich surface termination functional groups and two-dimensional multilayer structure. In this work, MXene was introduced to the membrane by vacuum-assisted filtration processes, and the formed interlayer channel facilitated the construction of recognition sites and molecular transmission. In this paper, PDA@MXene@PDA@SiO2-PVDF dual-imprinted mixed matrix membrane (PMS-DIMs) were developed by the cooperative dual-imprinting strategy, which was used for the adsorption of shikimic acid (SA). Firstly, SiO2-PVDF nanofiber basement membrane were prepared by electrospinning method and the first Polydopamine (PDA)-based imprinted layer was constructed on the membrane. PDA not only realized the imprinting process, PDA modification was used to give MXene nanosheets better antioxidant properties and to confer the SiO2-PVDF nanofiber membrane the interface stability. After that, the second-imprinted sites were constructed on the stacked MXene nanosheets surface as well as between the layers. The SA dual-imprinted sites significantly increased the efficiency of the selective adsorption efficiency, when the template molecule passed through the membrane, the cooperative dual-imprinting strategy enabled multiplex recognition and adsorption of template molecules. As a consequence, which greatly improving the rebinding ability(262.17 g m−2), and mselectivity factors (βCatechol/SA, βP-HB/SA, βP-NP/SA were 2.34, 4.50 and 5.68). High stability proved the potentials of the PMS-DIMs for practical application. Precise SA-recognition sites were constructed on the PMS-DIMs, PMS-DIMs not only exhibit excellent selective rebinding properties but also have high permeability.

Discontinuous cooperative imprinting idea based on MXene-nanocomposite membrane for high structurally stable recognition and separation of shikimic acid

Ti3C2Tx (MXene) has attracted wide research interest for application in various fields due to its rich surface chemistry and 2D multilayer structure. However, its application remains challenging due to its oxidative fragility. Here, Polydopamine (PDA) act as both the functional monomer and crosslinker, could self-polymerize to form a stable multifunction hybrid coating on MXene surfaces, which enhances the antioxidant properties of the MXene while form the first SA-imprinted sites. During the second imprinting process, the PDA-based first SA-imprinted recognition layer acted as the “anchor” to trigger the second SA-imprinted layer (sol–gel boronate affinity imprinting layer). Benefiting from the above mentioned discontinuous cooperative imprinting strategy, an efficient SA dual-imprinted sites was constructed on the surface of MXene-based molecularly imprinted membrane(P-MBMs). Such cooperative imprinting strategy could generate highly specific and strong binding sites for the template molecule. Adsorption isotherm and dynamics, permeation selectivity, and stability were studied, with ideal rebinding ability for SA (363.29 g m−2) and permselectivity factors (βCatechol/SA = 2.40, βP-HB/SA = 5.50, βP-NP/SA = 7.54), respectively. In-situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) analysis revealed that the high selectivity of P-MBMs for SA was mainly realized by the SA dual-imprinted sites constructed on the membrane. In addition, dynamic penetration test was first used to to verify the stability of the P-MBMs to specifically recognize the target molecule in this work. Compared to one-step imprinting approaches, the proposed discontinuous cooperative imprinting strategy would offer precise recognition sites, multiple strengthening of SA-imprinted sites could improve the selective separation performance of P-MBMs.

A Novel Aptamer-Imprinted Polymer-Based Electrochemical Biosensor for the Detection of Lead in Aquatic Products.

Lead contamination in aquatic products is one of the main hazard factors. The aptasensor is a promising detection method for lead ion (Pb(II)) because of its selectivity, but it is easily affected by pH. The combination of ion-imprinted polymers(IIP) with aptamers may improve their stability in different pH conditions. This paper developed a novel electrochemical biosensor for Pb(II) detection by using aptamer-imprinted polymer as a recognition element. The glassy carbon electrode was modified with gold nanoparticles and aptamers. After the aptamer was induced by Pb(II) to form a G-quadruplex conformation, a chitosan-graphene oxide was electrodeposited and cross-linked with glutaraldehyde to form an imprint layer, improving the stability of the biosensor. Under the optimal experimental conditions, the current signal change (∆I) showed a linear correlation of the content of Pb(II) in the range of 0.1-2.0 μg/mL with a detection limit of 0.0796 μg/mL (S/N = 3). The biosensor also exhibited high selectivity for the determination of Pb(II) in the presence of other interfering metal ion. At the same time, the stability of the imprinted layer made the sensor applicable to the detection environment with a pH of 6.4-8.0. Moreover, the sensor was successfully applied to the detection of Pb(II) in mantis shrimp.

Selective and ratiometric fluorescence sensing of bisphenol A in canned food based on portable fluorescent test strips

In this study, a conversion method and molecular imprinting technology were used to design molecularly imprinted polymers (MIP)-based ratiometric fluorescence test papers. The ZnO quantum dots (ZnO QDs) acted as the background quantum dots and ZIF-8 raw material. Carbon dots (CDs) were used as the identification signals. The imprinting layer achieved a selective function. Therefore, a ZnO@ZIF-8/CDs@MIPs sensor was designed for the detection of Bisphenol A (BPA). The sensor exhibited a fast response time for BPA detection. In addition, the sensor demonstrated that effective detection of BPA can still be achieved in complex environments. The detection limit of this sensor was 0.778 nM with a linear range of 0–60 nM. The corresponding test solutions exhibited clear changes from blue to yellow. The selectivity experiments results demonstrated that ZnO@ZIF-8/CDs@MIPs only exhibit excellent selective recognition effect for BPA. ZnO@ZIF-8/CDs@MIPs-2 was used for the detection of BPA in canned food and compared with the results of HPLC detection of BPA. The two spiked recovery ranges were 96.58–102.04% and 97.43–103.82%, respectively. In addition, the prepared ZnO@ZIF-8/CDs@MIPs-2 test paper visually recognized BPA under ultraviolet light. This study provides guidelines for the design and application of fluorescent test papers for quick detection in practical applications.

Ratiometric Fluorescence Capillary Sensor-Integrated Molecular Imprinting for Simultaneous Detection of Two Biological Indicators of Parkinson's Disease.

This work proposed ratiometric fluorescence capillary sensing system-integrated molecular imprinting with highly sensitive and selective detection for two biological indicators of Parkinson's disease (homovanillic acid (HVA) and Al3+). In this research, the silicon carbon quantum dot and the near-infrared CdTe quantum dot as luminescence sources were doped to an imprinted layer, which was attached to the inner surface wall of an amino-functionalized capillary. The fluorescence emissions of the ratiometric fluorescence capillary-imprinted sensor at 434 and 707 nm were quenched by HVA, and only the fluorescence emission at 434 nm was quenched by Al3+. Ratiometric fluorescence capillary sensing system-integrated molecular imprinting was used to detect simultaneously HVA and Al3+ with linearity over 1.0 × 10-9-2.5 × 10-7 and 1.0 × 10-9-1.1 × 10-7 M, respectively. The sensor showcased detection limitations of 8.7 × 10-10 and 9.8 × 10-10 M, indicating that the ratiometric fluorescence capillary sensing system-integrated molecular imprinting had great potential application for detecting HVA and Al3+ in serum and urine samples. The ratiometric fluorescence capillary sensing system-integrated molecular imprinting achieved highly sensitive and selective detection of HVA and Al3+ with a microvolume test dosage of 18 μL, which provided a new way for early diagnosis and disease monitoring of Parkinson's disease.

Surface imprinting by using bi-functional monomers on spherical template magnetite for selective detection of levodopa in biological fluids

The present work introduces an innovative biosensing platform for greatly sensitive determination of levodopa medicine. Initially, spherical magnetic (SM) nanoparticles were prepared by hydrothermal fabrication approach and used as a pattern to make spherical magnetic molecular imprinted polymer (SMMIP). Afterward, levodopa-molecularly imprinted layer was grown on the surface of the spherical magnetic pattern by electropolymerization with dopamine and resorcinol as bi-functional monomers and levodopa as a template molecule, which enhanced the specific recognition of the sensing platform to levodopa. The presence of SM nanoparticles could not only accelerate the mass transfer, the electron transport rate, and improve specific surface area of the electrode but also facilitate the recognition of the polymer, in this way increasing the current response and improving the performance of the biosensor. The superior sensing efficiency of the presented biosensor was confirmed based on the low limit of detection of 10 nmol L−1 which represented two linear ranges from 0.5 to 200 μmol L−1 and 200–1000 μmol L−1 for levodopa. More importantly, the practicability of the biosensor was proved by detecting levodopa in tablet, blood serum and plasma, implying that the sensing platform was suitable for monitoring levodopa in actual biological fluid and medicine.

Multilayer-functionalized molecularly imprinted nanocomposite membranes for efficient acteoside separation

Acteoside (ACT) and echinoside (ECH) had similar structure and property in the phenylethanoid glycosides (PhGs), thus the selective separation of ACT and ECH was a bottleneck problem. In this study, ACT was used as template molecule, and multilayer-functionalized of molecularly imprinted nanocomposite membranes (A-MINMs) were designed to efficient ACT separation. The A-MINMs were fabricated by using polydopamine (PDA), polyethylenimine functionalized mesoporous silica (PEI/MCM-41) and ACT imprinted layer to modify the surface of polyvinylidene fluoride (PVDF). The PDA layer was a stable surface adhesive, and the filler PEI/MCM-41 was uniformly bonded to the PVDF membrane surface, thus constructing the second layer on the membrane surface. The PEI/MCM-41 layer adjusted the pore uniformity of the membrane surface, and contained abundant amino groups, which provided an ACT imprinted platform to trigger the imprinted polymerization to form an imprinted layer. The ACT imprinted layer had a large number of ACT imprinted sites and cavities, which could specifically recognize ACT, realizing the efficient ACT separation. The results indicated the high rebinding capacity (108.74 mg/g) and permselectivity (βACT/ECH = 9.43) of A-MINMs. Therefore, multilayer-functionalized A-MINMs has a potential application prospect in the field of natural product separation membrane materials.

Imprinted ratiometric fluorescence capillary sensor based on UiO-66-NH2 for rapid determination of sialic acid

Development of method with micro-volume reagent usage and high selectivity for rapid determination of valuable disease-related biomarkers is of great importance for disease surveillance. Herein, a novel ratiometric fluorescence capillary imprinted sensor was developed for highly selective fluorescence determination of sialic acid (SA) based on luminescent metal-organic framework (UiO-66-NH2). In this strategy, the imprinted pre-polymer with double emissions was sucked into the capillary to grow imprinted layer on the inner wall of the capillary. In presence of SA, the blue fluorescence (440 nm) served as fluorescence response signal was quenched due to the electron transfer mechanism between metal organic framework and SA while the red fluorescence (655 nm) served as the reference signal was remained. Within SA concentration linear range of 1.0 × 10−7–3.0 × 10−4 M, the ratiometric fluorescence capillary imprinted sensor was applied to detect SA in human serum and saliva samples successfully with a detection limit of 2.5 × 10−8 M. A sensitive and selective fluorescence method with micro-volume sample consumption (15 μl) for determination of SA in practical samples was established.

Synthesis of environmental-friendly ion-imprinted magnetic nanocomposite bentonite for selective recovery of aqueous Sc(III)

A novel reusable ion imprinted nanocomposite magnetic bentonite(IIPNMB) was prepared for selective recovery of aqueous scandium. Based on the fact that oxyphosphorus functional groups in sodium tripolyphosphate have good affinity to Sc(III) and chitosan is rich in hydroxy and amino active sites, they were chosen to build ion imprinted layers. Mesoporous IIPNMB showed good adsorption performance. The pseudo second-order kinetic model and Langmuir model fit the experimental data. According to XPS features, the amino, hydroxyl, PO and PO bonds of the adsorbents had electrostatic interaction and complexation with Sc(III), leading to the good selectivity of IIPNMB for Sc(III). In addition, the material atomic structure was proposed based on the chemical structure of IIPNMB for DFT calculation of ion imprinting adsorption, which clearly proved that the adsorption process of Sc(III) was stable, and it gave another proof for the mechanism of the selective extraction.

Determination of acrylamide by a quartz crystal microbalance sensor based on nitrogen-doped ordered mesoporous carbon composite and molecularly imprinted poly (3-thiophene acetic acid) with gold nanoparticles

In this study, a quartz crystal microbalance (QCM) sensor based on nitrogen-doped ordered mesoporous carbon modified-AuNPs (NOMC-Au) modified layer and cross-linked 3-thiopheneacetic acid functionalized AuNPs ([email protected]) imprinted layer was developed for the detection of acrylamide as a hazardous substance in thermal processing. The composite modification layer formed by NOMC-Au was used as support material for QCM gold chips (AuE), and [email protected] were then introduced to the highly selective imprinting modification layer by electropolymerization using propionamide as a template. The use of [email protected] based molecularly imprinted polymer (MIP) on QCM was also evaluated and optimized, and the data were compared with non-imprinted polymer (NIP) and MIP/AuE chip layers. Results showed that a highly crosslinked three-dimensional reticular imprinted layer improved the acrylamide signals in the range of 0.08 ng/mL −100.0 ng/mL, and the sensor was suitable for food samples analysis at concentrations as low as 5.1 pg/mL. The proposed QCM sensor is very useful for future selective and sensitive detection of acrylamide in food samples.

Molecularly Imprinted Polymer Modified Electrode Prepared by In Situ Polymerization for Specific Determination of Norfloxacin

Herein, a molecularly imprinted sensor was proposed via in situ polymerization technique for specifically sensing norfloxacin (NFX). The sensor indicates high stability due to the imprinting layer covalently conjugated on the surface of aminated glass carbon electrode. Emphasized, it shows excellent selectivity and specificity towards NFX ascribed to the unique characteristics of molecularly imprinted polymers (MIPs). Even in the presence of 10-fold concentration of its structural analog ciprofloxacin, there is no evident interference in the determination of NFX. Under optimized conditions, the oxidation current of square wave voltammetry (typically at +1.03 V vs Ag/AgCl) increases linearly with the concentration of NFX increasing in the ranges of 0.1–10 μM and 10−160 μM. And the limit of detection is 0.004 μM (based on a signal-to-noise ratio of 3). Average recoveries from (spiked) real water samples are between 99.63% and 103.20% with relative standard derivations less than 4.67% (n = 3) at three spiked levels, validated by independent assays of HPLC. This work provides a successful model for fast preparing MIP-based electrochemical sensors for detecting trace drug residues in environmental samples.

Facile synthesis of novel helical imprinted fibers based on zucchini-derived microcoils for efficient recognition of target protein in biological sample

Highly selective recognition and purification of target proteins from complex biological matrices remains a challenging subject in natural and life sciences. Compared with natural recognition receptors, artificial imprinted polymers are an ideal alternative candidate. In this study, we report a novel method to prepare helical protein imprinted fibers (HPIFs) with zucchini-derived microcoils as a carrier, firstly. Inspired by the self-polymerization of adhesive proteins in mussels, dopamine and 3,4-dihydroxyphenylacetic acid were chosen as bifunctional monomers for the first time to form a biocompatible imprinted layer. The chemical/physical properties and recognition performance of HPIFs were studied in a series of experiments. Additionally, the practicability of HPIFs was verified by specifically recognizing target protein in complex egg white sample. The one-step synthesis process and excellent binding performance of HPIFs make them a promising material for protein recognition and purification, and endow HPIFs with potential application value in the food, chemical and pharmaceutical fields.

Construction of an Ultrasensitive Molecularly Imprinted Virus Sensor Based on an "Explosive" Secondary Amplification Strategy for the Visual Detection of Viruses.

Viral outbreaks have caused great disruptions to the economy and public health in recent years. The accurate detection of viruses is a key factor in controlling and overcoming epidemics. In this study, an ultrasensitive molecularly imprinted virus sensor was developed based on an "explosive" secondary amplification strategy. Magnetic particles coated with carbon quantum dots (Fe3O4@CDs) were used as carriers and fluorescent probes, while aptamers were introduced into the imprinting layer to enhance the specific recognition of the target virus enterovirus 71 (EV71). When EV71 was captured by the imprinted particles, the fluorescence of the CDs was quenched, especially after binding to the aptamer-modified ZIF-8 loaded with a large amount of phenolphthalein, thereby resulting in signal amplification. Then, when adjusting the pH of the solution to 12, the decomposition of ZIF-8 released phenolphthalein, which turned the solution red, leading to the second "explosive" amplification of the signal. Therefore, the detection of EV71 with ultrasensitivity was achieved, which allows for visual detection by the naked eye in the absence of any instruments. The detection limits for fluorescence and visualization detection were 8.33 fM and 2.08 pM, respectively. In addition, a satisfactory imprinting factor of 5.4 was achieved, and the detection time only needed 20 min. It is expected that this fluorescence-colorimetric dual-mode virus molecularly imprinted sensor will show excellent prospects in epidemic prevention and rapid clinical diagnosis.

An ultra-sensitive tailor-made sensor for specific adsorption and separation of rutin based on imprinted cavities on magnetic sensing platform

Present study details the expansion of a sensing platform based on magnetic imprinted layer system for plant pigment. A scalable, simple, cost-effective and novel magnetic imprinted layer constructed of Fe3O4@polyaniline/reduce graphene oxide molecular imprinted membrane (M@PANI/rGO MIP) was manufactured on the surface of the magnetic carbon paste electrode (MCPE). The prepared M@PANI/rGO MIP was investigated with all the significant physical characteristics including composition, topography and morphology. The synthesized M@PANI/rGO MIP was displayed stability and exceptional electrochemical activity due to presenting tailor-made receptors. Upon the electrochemical investigation, a sensitive MIP sensing platform for the detection of rutin led to two linear calibration curves in the range of 0.01–1 pM and 0.00001–10 µM and an ultralow detection limit (0.356 fM). Consequently, the proposed MIP platform evidently was featured accurate detection of rutin in fruits and could be recommended for real-time analysis.

A recognition strategy combining effective boron affinity technology and surface imprinting to prepare highly selective and easily recyclable polymer membrane for separation of drug molecule

Cellulose acetate membrane (CAM) has become one of the most widely used membrane materials by virtue of stability and hydrophilicity. In this work, to achieve the aim of selective recognition and separation of drug molecule shikimic acid (SA), an effective recognition tactics was proposed by combining boron affinity technology with surface imprinting strategy based on cellulose acetate membrane with low price and biocompatibility. The supporting CAM material was prepared through the phase inversion technique by continuous adjustment of different factors including solvent type and kinds of pore-forming agents, and the optimal CAM with multistage structure and highly porosity was applied for the imprinting of SA. Then the imprinted polymer membrane (MIPs-CAM) was developed via boron affinity surface imprinting polymerization. Various methods (FT-IR, UV–vis, SEM, XPS, AFM and TGA) were used to characterize the structure, morphology, elemental composition, surface roughness and thermal property of the obtained membrane. The as-prepared MIPs-CAM showed homogeneous and abundant imprinted layer, good thermal stability. The batch adsorption results showed that the MIPs-CAM had fast adsorption kinetics, specific recognition ability, and the adsorption capacity could obtain 63.598 mg g−1, which was two times higher than that of non-imprinted membrane (NIPs-CAM). The adsorption isotherms conformed to the Langmuir isotherm and the adsorption processes were spontaneous and endothermic. Additionally, the adsorption capacity of MIPs-CAM still reached 85% of the initial result after five cycles. The experimental results revealed that the molecularly imprinted membrane possessed the advantages of high selectivity and easy recovery compared with the traditional molecular imprinted polymers for SA separation. These results indicate that boron affinity MIPs-CAM with high performance will provide a promising platform for the separation and purification of other cis-diol drug molecules from environmental resources.

A mild and safe gas-responsive molecularly imprinted sensor for highly specific recognition of hepatitis B virus

Virus outbreaks frequently, and effective detection of the virus is the key step in the prevention and control of the epidemic. A highly specific gas-responsive molecular imprinting resonance light scattering sensor was designed, and applied to detect hepatitis B virus. In this strategy, the electrical properties of the amines in the imprinted cavity can be varied by switching N2/CO2. As a result, the binding energy of the imprinted site and target virus significantly altered to achieve rapid binding and release under mild and safe conditions. The rebind virus can be efficiently removed in situ without any extra reagents or operations, which might damage the imprinting layer. Moreover, the changes in electrical properties also play an important role in identifying the specificity and sensitivity of the target virus. A satisfactory imprinting factor of 6.7 and detection limit of 1.9 pM were achieved. The cyclic experiments indicate that the gas response sensor has excellent stability and reproducibility and is easy to be recycled and reused. This strategy is expected to provide a new green method for the simple and rapid screening of viral infection and control of virus epidemic.

Surface and interface engineering of Z-scheme 1D/2D imprinted CoZn-LDH/C3N4 nanorods for boosting selective visible-light photocatalytic activity

Recently, the emergence of more and more coexisting organic contaminants aggravates the difficulty of water treatment and poses a threat to public health. Molecularly imprinted photocatalysts allow a highly selective removal of target active compounds, rendering wide applications in complex environmental treatment. However, the synergistic recognition and degradation performance is usually restricted by the intrinsic structural characteristics of traditional photocatalysts and the affinity barrier between semiconductor substrate and organic imprinted layer. Herein, we synthesized Z-scheme molecularly imprinted photocatalysts with CoZn-LDH heterostructure supported by porous C3N4 nanorods (MIP-CoZn-LDH@C3N4). Due to the excellent light capture and high active cavities, the photodegradation rate of MIP-CoZn-LDH@C3N4 to tetracycline (TC) target could reach 79.8% under visible light within 60 min. Noticeably, the material possessed outstanding ability of selective recognition and photodegradation of TC in coexisting interference solution (kimprinted was 2.18 to ciprofloxacin and 2.33 to cephalothin, respectively). The mode of selective photodegradation and pathways were systematically discussed based on the deep evaluation of the mechanism experiments. Our study opens a new insight into the design of photocatalyst with selective degradation performance for the requirements of practical environmental applications.

Design and synthesis of Fe3O4@Au@cyclodextrin-molecularly imprinted polymers labeled with SERS nanotags for ultrasensitive detection of transferrin

As an important clinical biomarker, transferrin (TRF) plays an indispensable role in the function regulation of human body and its concentration reflects the occurrence of some diseases. Herein, a sensor based on magnetic molecularly imprinted polymers (MMIPs) and surface-enhanced Raman scattering (SERS) was developed for the sensitive detection of TRF. For this purpose, Fe3O4@Au@cyclodextrin-MIPs were successfully synthesized using β-cyclodextrin as the functional monomer because its appropriate size, hydrophobic cavities, and hydroxyl groups benefitted anchoring TRF through noncovalent interactions. An appropriate hydrophilic imprinted layer was generated by self-copolymerization of dopamine and m-aminophenylboronic acid (APBA). After TRF was captured by Fe3O4@Au@cyclodextrin-MIPs, it was labeled with 4-mercaptophenylboronic acid-modified AgNPs as SERS nanotags to construct a sandwich structured sensor. This MMIP-SERS sensor behaved excellent identification and detection performances toward TRF since Fe3O4@Au@cyclodextrin-MIPs contributed to high specificity of the assay and SERS provided high sensitivity. Furthermore, the reliability and feasibility of the sensor in real serum samples were verified by determining TRF from liver disease patients, suggesting its great potential in clinical TRF detection.

A surface protein-imprinted biosensor based on boronate affinity for the detection of anti-human immunoglobulin G.

A surface protein-imprinted biosensor was constructed on a screen-printed carbon electrode (SPCE) for the detection of anti-human immunoglobulin G (anti-IgG). The SPCE was successively decorated with aminated graphene (NH2-G) and gold nanobipyramids (AuNBs) for signal amplification. Then 4-mercaptophenylboric acid (4-MPBA) was covalently anchored to the surface of AuNBs for capturing anti-IgG template through boronate affinity binding. The decorated SPCE was then deposited with an imprinting layer generated by the electropolymerization of pyrrole. After removal of the anti-IgG template by the dissociation of the boronate ester in an acidic solution, three-dimensional (3D) cavities complementary to the anti-IgG template were formed in the imprinting layer of polypyrrole (PPy). The molecularly imprinted polymers (MIP)-based biosensor was used for the detection of anti-IgG, exhibiting a wide linear range from 0.05 to 100 ng mL−1 and a low limit of detection of 0.017 ng mL−1 (S/N = 3). In addition, the MIP-based anti-IgG biosensor also shows high selectivity, reproducibility and stability. Finally, the practicability of the fabricated anti-IgG biosensor was demonstrated by accurate determination of anti-IgG in serum sample.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00604-022-05204-w.