A competitive-type photoelectrochemical aptasensor for 17 beta-estradiol detection in microfluidic devices based on a novel Au@Cd:SnO2/SnS2 nanocomposite.

A competitive-type photoelectrochemical (PEC) aptasensor coupled with a novel Au@Cd:SnO2/SnS2 nanocomposite was designed for the detection of 17ß-estradiol (E2) in microfluidic devices. The designed Au@Cd:SnO2/SnS2 nanocomposites exhibit high photoelectrochemical activity owing to the good matching of cascade band-edge and the efficient separation of photo-generated e-/h+ pairs derived from the Cd-doped defects in the energy level. The Au@Cd:SnO2/SnS2 nanocomposites were loaded into carbon paste electrodes (CPEs) to immobilize complementary DNA (cDNA) and estradiol aptamer probe DNA (E2-Apt), forming a double-strand DNA structure on the CPE surface. As the target E2 interacts with the double-strand DNA, E2-Apt is sensitively released from the CPE, subsequently increasing the photocurrent intensity due to the reduced steric hindrance of the electrode surface. The competitive-type sensing mechanism, combined with high PEC activity of the Au@Cd:SnO2/SnS2 nanocomposites, contributed to the rapid and sensitive detection of E2 in a "signal on" manner. Under the optimized conditions, the PEC aptasensor exhibited a linear range from 1.0 × 10-13 mol L-1 to 3.2 × 10-6 mol L-1 and a detection limit of 1.2 × 10-14 mol L-1 (S/N = 3). Moreover, the integration of microfluidic device with smartphone controlled portable electrochemical workstation enables the on-site detection of E2. The small sample volume (10 µL) and short analysis time (40 min) demonstrated the great potential of this strategy for E2 detection in rat serum and river water. With these advantages, the PEC aptasensor can be utilized for point-of-care testing (POCT) in both clinical and environmental applications.

Bone Homeostasis Modulating Orthopedic Adhesive for the Closed-Loop Management of Osteoporotic Fractures.

Patients with osteoporotic fractures often require effective fixation and subsequent bone repair. However, currently available materials are often limited functionally, failing to improve this cohort's outcomes. Herein, kaempferol-loaded mesoporous bioactive glass nanoparticles (MBGNs)-doped orthopedic adhesives are prepared to assist osteoporotic fracture fixation and restore dysregulated bone homeostasis, including promoting osteoblast formation while inhibiting osteoclastic bone-resorbing activity to synergistically promote osteoporotic fracture healing. The injectability, reversible adhesiveness and malleable properties endowed the orthopedic adhesives with high flexibility and hemostatic performance to adapt to complex clinical scenarios. Moreover, Ca2+ and SiO4 4- ions released from MBGNs can accelerate osteogenesis via the PI3K/AKT pathway, while kaempferol mediated osteoclastogenesis inhibition and can slow down the bone resorption process through NF-κB pathway, which regulated bone regeneration and remodeling. Importantly, implementing the orthopedic adhesive is validated as an effective closed-loop management approach in restoring the dysregulated bone homeostasis of osteoporotic fractures.

Core-shell nanocomposite of flower-like molybdenum disulfide nanospheres and molecularly imprinted polymers for electrochemical detection of anti COVID-19 drug favipiravir in biological samples.

A novel electrochemical sensor is reported for the detection of the antiviral drug favipiravir based on the core-shell nanocomposite of flower-like molybdenum disulfide (MoS2) nanospheres and molecularly imprinted polymers (MIPs). The MoS2@MIP core-shell nanocomposite was prepared via the electrodeposition of a MIP layer on the MoS2 modified electrode, using o-phenylenediamine as the monomer and favipiravir as the template. The selective binding of target favipiravir at the MoS2@MIP core-shell nanocomposite produced a redox signal in a concentration dependent manner, which was used for the quantitative analysis. The preparation process of the MoS2@MIP core-shell nanocomposite was optimized. Under the optimal conditions, the sensor exhibited a wide linear response range of 0.01 ~ 100 nM (1.57*10-6 ~ 1.57*10-2 µg mL-1) and a low detection limit of 0.002 nM (3.14*10-7 µg mL-1). Application of the sensor was demonstrated by detecting favipiravir in a minimum amount of 10 µL biological samples (urine and plasma). Satisfied results in the recovery tests indicated a high potential of favipiravir monitoring in infectious COVID-19 samples.

Analysis of peripheral bone reconstruction after the failure of hip osteonecrosis treatment with porous tantalum rod implantation.

PURPOSE: Failure of porous tantalum rod (PTR) implantation in treating early osteonecrosis of femoral head (ONFH) has been frequently reported, but the underlying mechanism remains uncertain, which raised the concern of its efficacy. The study aimed to discuss the underlying mechanism from the perspectives of bone reconstruction and pathological changes. METHODS: Five patients with PTR implantation experienced total hip arthroplasty (THA) due to recurrent pain, whose femoral heads were collected as "tantalum group." Normal (fracture) and necrotic femoral heads were respectively collected (both n = 5) after THA. The bone quality and structure, biomechanical properties, and histopathological features were analyzed by micro-CT scanning, mechanical measurement, and histological examination. RESULTS: Both the tantalum group and necrotic group had significantly poorer bone quantity and quality than the normal group. Three-dimensional imaging reconstruction showed that the trabeculae of the tantalum group were poorest in quality. Significant differences in terms of bone quality, structure, and biomechanical properties were present between the inside and outside regions around PTR, which revealed abnormal bone reconstruction. Biomechanical analysis revealed inferior properties in the tantalum group and necrosis group. H&E staining demonstrated neutrophil infiltration among the peripheral trabeculae around PTR, and the inflammation cells were significantly more abundant than that in the normal and necrosis groups. CONCLUSION: Abnormal bone reconstruction around PTR was an important cause for failure of PTR implantation in the treatment of ONFH, which was related to biomechanical stress distribution and chronic inflammation infiltration. Insufficient biomechanical support and inflammatory trabeculae edema might account for the recurrent pain.

Stomatal conductance of tomato leaves is regulated by both abscisic acid and leaf water potential under combined water and salt stress.

Stomatal conductance (gs ) affects water use efficiency (WUE) through coordinating photosynthesis and transpiration and is regulated by chemical and/or hydraulic signals. However, the regulation mechanism of gs of tomato leaves has not been fully explored under combined water and salt stress. Here, we set up four salt treatments and two water treatments in a climate greenhouse and measured stomatal morphologies and conductance and other photosynthesis parameters. Water and salt stress reduced stomatal length (SL), width, perimeter, area (amax ), density (SD), and the maximum stomatal conductance (gsmax ). Water and salt stress had a separate weakening effect on net photosynthetic rate (A) and transpiration rate but interactively reduced gs . The contents of abscisic acid (ABA) and Na+ in tomato leaves increased with the NaCl concentration, while leaf water potential (Ψl ) and chlorophyll content decreased. Under full irrigation, gsmax was coordinated by SD and amax , and gs by ABA content under salt stress. Under water and salt combined stress, gsmax was affected by amax , and gs was coordinated with ABA and Ψl . The decrease of A was caused by both a reduction of chlorophyll content and gs under water and salt stress. Intrinsic WUE did not reduce under full irrigation or mild to moderate salt stress but decreased under a combination of water and severe salt stress, indicating that the leaves of the tested tomato cultivar performed better under moderate salt stress. Collectively, these results can provide useful insights for the efficient management of water and salt to adapt to drought and high salt environments.

Tremella-like graphene-Au composites used for amperometric determination of dopamine.

Electrochemical detection of dopamine (DA) plays an important role in medical diagnosis. In this paper, tremella-like graphene-Au (t-GN-Au) composites were synthesized by a one-step hydrothermal method for selective detection of DA. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterize as-prepared t-GN-Au composites. The t-GN-Au composites were directly used for the determination of DA via cyclic voltammetry (CV) and the chronoamperometry (CA) technique. CA measurement gave a wide linear range from 0.8 to 2000 µM, and the detection limit of 57 nM (S/N = 3) for DA. The mechanism and the heterogeneous electron transfer kinetics of the DA oxidation were discussed in the light of rotating disk electrode (RDE) experiments. Moreover, the modified electrode was applied to the determination of DA in human urine and serum samples.

Needle-in-needle electrochemical sensor for in-vivo monitoring of anticancer drug etoposide.

Therapeutic drug monitoring (TDM) serves as a potent tool for adjusting drug concentration within a reasonable range. However, continuous monitoring of anticancer drugs in-vivo presents a significant challenge. Herein, we propose a needle-in-needle electrochemical sensor based on an acupuncture needle electrode, capable of monitoring the anticancer drug etoposide in the peritoneal cavity of living rats. The acupuncture needle was modified with Au nanoparticles and etoposide-templated molecularly imprinted polymer (MIP), resulting in high sensitivity and selectivity in the electrochemical detection of etoposide. The modified acupuncture needle (0.16 mm diameter) was anchored inside a syringe needle (1.40 mm diameter), allowing the outer syringe needle to protect the modified materials of the inner acupuncture needle during skin piercing. Due to the unique needle-in-needle design, high stability was obtained during in-vivo etoposide monitoring. Connecting to a smartphone-controlled portable electrochemical workstation, the needle-in-needle sensor offers great convenience in point-of-care TDM. Moreover, the electrode materials on the acupuncture needle were carefully characterized and optimized. Under the optimized conditions, low detection limits and wide linear range were achieved. This work provides new insights into acupuncture needle electrochemical sensors and further expands the feasibility for real-time and in-vivo detection.

Triple-functional bone adhesive with enhanced internal fixation, bacteriostasis and osteoinductive properties for open fracture repair.

At present, effective fixation and anti-infection implant materials represent the mainstay for the treatment of open fractures. However, external fixation can cause nail tract infections and is ineffective for fixing small fracture fragments. Moreover, closed reduction and internal fixation during the early stage of injury can lead to potential bone infection, conducive to bone nonunion and delayed healing. Herein, we designed a bone adhesive with anti-infection, osteogenic and bone adhesion fixation properties to promote reduction and fixation of open fractures and subsequent soft tissue repair. It was prepared by the reaction of gelatin (Gel) and oxidized starch (OS) with vancomycin (VAN)-loaded mesoporous bioactive glass nanoparticles (MBGNs) covalently cross-linked with Schiff bases. Characterization and adhesion experiments were conducted to validate the successful preparation of the Gel-OS/VAN@MBGNs (GOVM-gel) adhesive. Meanwhile, in vitro cell experiments demonstrated its good antibacterial effects with the ability to stimulate bone marrow mesenchymal stem cell (BMSCs) proliferation, upregulate the expression of alkaline phosphatase (ALP) and osteogenic proteins (RunX2 and OPN) and enhance the deposition of calcium nodules. Additionally, we established a rat skull fracture model and a subcutaneous infection model. The histological analysis showed that bone adhesive enhanced osteogenesis, and in vivo experiments demonstrated that the number of inflammatory cells and bacteria was significantly reduced. Overall, the adhesive could promote early reduction of fractures and antibacterial and osteogenic effects, providing the foothold for treatment of this patient population.

Non-Coding-RNA-Activated Core/Chitosan Shell Nanounits Coated with Polyetheretherketone for Promoting Bone Regeneration and Osseointegration via Osteoimmunology.

Bone implant outcome and bone regeneration properties can be improved by the immunomodulation of exosomes (Exos) derived from bone marrow mesenchymal stem cells (BMSCs), which contain cytokines, signaling lipids, and regulatory miRNAs. Analysis of miRNAs in BMSCs-derived exosomes showed that miR-21a-5p exhibited the highest expression and was associated with the NF-κB pathway. Hence, we developed an implant with miR-21a-5p functionality to promote bone incorporation by immunoregulation. Mediated by the potent interaction between tannic acid (TA) and biomacromolecules, the tannic acid modified mesoporous bioactive glass nanoparticles coated with miR-21a-5p (miR-21a-5p@T-MBGNs) were reversibly attached to TA-modified polyetheretherketone (T-PEEK). Cocultured cells could phagocytose miR-21a-5p@T-MBGNs slowly released from miR-21a-5p@T-MBGNs loaded T-PEEK (miMT-PEEK). Moreover, miMT-PEEK boosted macrophage M2 polarization via the NF-κB pathway to increase BMSCs osteogenic differentiation. In vivo testing of miMT-PEEK in the rat air-pouch model and rat femoral drilling model indicated effective macrophage M2 polarization, new bone formation, and excellent osseointegration. Overall, the osteoimmunomodulation of the miR-21a-5p@T-MBGNs-functionalized implant promoted osteogenesis and osseointegration.

circIFNGR2 regulating ankylosing spondylitis-associated inflammation through macrophage polarization.

Macrophages activation is crucial in pathogenesis of rheumatic diseases like ankylosing spondylitis (AS). Circular RNAs (circRNAs)-induced macrophage-associated inflammation participates in many autoimmune diseases but remains elusive in AS. Here, we verified increased expression of circIFNGR2 in peripheral blood mononuclear cells from patients with AS and its expression levels were correlated with the AS severity. In vitro assays revealed that circIFNGR2 enhances macrophage proliferation, and regulates M1/M2 macrophage polarization and NF-κB/Akt pathways. We identified that circIFNGR2 promoted the expression of iNOS/TNFα and M1 polarization, and restrained M2 polarization by sponging miR-939. Additionally, the RNA-binding protein, eIF4A3, was found to enhance the production of circIFNGR2. Interestingly, miR-939 attenuated joint damage in collagen-induced arthritis mice, whereas circIFNGR2 reversed this effect. Our findings highlight the pro-inflammatory roles of eIF4A3-induced circIFNGR2 in AS by modulating macrophage-associated inflammation through miR-939.

Biodegradable Dual-Cross-Linked Hydrogels with Stem Cell Differentiation Regulatory Properties Promote Growth Plate Injury Repair via Controllable Three-Dimensional Mechanics and a Cartilage-like Extracellular Matrix.

Recent breakthroughs in cell transplantation therapy have revealed the promising potential of bone marrow mesenchymal stem cells (BMSCs) for promoting the regeneration of growth plate cartilage injury. However, the high apoptosis rate and the uncertainty of the differentiation direction of cells often lead to poor therapeutic effects. Cells are often grown under three-dimensional (3D) conditions in vivo, and the stiffness and components of the extracellular matrix (ECM) are important regulators of stem cell differentiation. To this end, a 3D cartilage-like ECM hydrogel with tunable mechanical properties was designed and synthesized mainly from gelatin methacrylate (GM) and oxidized chondroitin sulfate (OCS) via dynamic Schiff base bonding under UV. The effects of scaffold stiffness and composition on the survival and differentiation of BMSCs in vitro were investigated. A rat model of growth plate injury was developed to validate the effect of the GMOCS hydrogels encapsulated with BMSCs on the repair of growth plate injury. The results showed that 3D GMOCS hydrogels with an appropriate modulus significantly promoted chondrogenic differentiation of BMSCs, and GMOCS/BMSC transplantation could effectively inhibit bone bridge formation and promote the repair of damaged growth plates. Accordingly, GMOCS/BMSC therapy can be engineered as a promising therapeutic candidate for growth plate injury.

ECM-Mimicking Hydrogels Loaded with Bone Mesenchymal Stem Cell-Derived Exosomes for the Treatment of Cartilage Defects.

It is well-established that treating articular cartilage injuries is clinically challenging since they lack blood arteries, nerves, and lymphoid tissue. Recent studies have revealed that bone marrow stem cell-derived exosomes (BMSCs-Exos) exert significant chondroprotective effects through paracrine secretions, and hydrogel-based materials can synergize the exosomes through sustained release. Therefore, this research aims to synthesize an ECM (extracellular matrix)-mimicking gelatin methacryloyl (GelMA) hydrogel modified by gelatin combined with BMSCs-derived exosomes to repair cartilage damage. We first isolated and characterized exosomes from BMSCs supernatant and then loaded the exosomes into GelMA hydrogel to investigate cartilage repair effects in in vitro and in vivo experiments. The outcomes showed that the GelMA hydrogel has good biocompatibility with a 3D (three-dimensional) porous structure, exhibiting good carrier characteristics for exosomes. Furthermore, BMSCs-Exos had a significant effect on promoting chondrocyte ECM production and chondrocyte proliferation, and the GelMA hydrogel could enhance this effect through a sustained-release effect. Similarly, in vivo experiments showed that GelMA-Exos promoted cartilage regeneration in rat joint defects and the synthesis of related cartilage matrix proteins.

Using a degradable three-layer sandwich-type coating to prevent titanium implant infection with the combined efficient bactericidal ability and fast immune remodeling property.

Titanium (Ti) implant-associated infections are a challenge in orthopedic surgery, for which a series of antibacterial coatings have been designed and fabricated to reduce the risk of bacterial contamination. Herein, we created a degradable three-layer sandwich-type coating to achieve long-term antibacterial effects while simultaneously reconstructing the local immune microenvironment. The vancomycin (Van)-loaded vaterite coating constitutes the outer and inner layers, whereas Interleukin-12 (IL-12)-containing liposomes embedded in sodium alginate constitutes the middle layer. Van, released from the vaterite, demonstrated a favorable and rapid bactericidal ability against the representative methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. The released IL-12 exhibited the desired immune reconstitution abilities, actively facilitating defenses against subsequent bacterial invasions. Furthermore, the biocompatibility and cell-binding feature of the multifunctional coating was beneficial for achieving solid interface intergradation. Overall, the benefits of the three-layer sandwich-type coating, including the convenient fabrication process, efficient antimicrobial activity, fast immune remodeling property, fine cell-binding feature, and biodegradability, highlight its promising translational potential in preventing implant infection. STATEMENT OF SIGNIFICANCE: To prevent titanium implant infections, researchers have designed various antibacterial coatings. However, most of these coatings focused only on killing the invading bacteria over a limited postoperative period. However, the local immune microenvironment is compromised during surgery. Local immune deflection impedes the ability of the local immune defenses to clear bacteria and limits immune memory building from active defense against long-term subsequent bacterial invasions. Furthermore, these coatings are usually nondegradable and differ substantially from bone components, thereby impairing the integration of the coating and bone interface and generating concerns about implant stability and bacterial contamination. In this work, we synthesized a degradable coating that provides sustained antibacterial activity, promotes immune reconstitution, and simultaneously achieves solid bone integration.

Sensitive and selective detection of puerarin based on the hybrid of reduced graphene oxide and molecularly imprinted polymer.

Puerarin, an important isoflavone, has been widely used for the treatment of angina and hypertension. In this work, we developed a novel electrochemical sensor for the detection of puerarin based on the hybrid of reduced graphene oxide (RGO) and molecularly imprinted polymer (MIP). The RGO/MIP sensor functions by target puerarin recognition and electro-oxidization via a two-proton and two-electron process, enabling the detection of puerarin with good selectivity and high sensitivity. The MIP layer was integrated on the surface of RGO by the electro-co-polymerization of o-phenylenediamine (monomer) and puerarin (template), resulting in high surface area, binding capacity, good conductivity and faster mass transfer. The nanostructure of the RGO/MIP hybrid was demonstrated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Experimental conditions involved in the sensor fabrication process were evaluated. Under the optimized condition, a wide linear range (0.02 µM ∼ 40 µM) and a low detection limit (0.006 µM) were achieved. The sensor was applied to detect puerarin in human urine and injection samples, and the result was comparable with that of the gold standard method of high-performance liquid chromatography (HPLC), indicating a promise in the further application to pharmacokinetics or therapeutic drug monitoring.

A novel sequence variant in COL10A1 causing spondylometaphyseal dysplasia accompanied with coxa valga: A case report.

RATIONALE: Spondylometaphyseal dysplasia (SMD) is an extremely rare disorder of irregular development of spine and metaphyses of long tubular bones. Mutations in the collagen type X alpha 1 gene were found to underlie this condition. Previously reported mutations in the N-terminal non-collagenous NC2 domain and C-terminal non-collagenous NC1 domain failed to be identified in some specific patients. PATIENT CONCERNS: A 23-year-old male was referred to us for fixed, angular thoracolumbar kyphosis with semi-paralysis, numbness, and tremor on his left lower limb. Marked hypoplasia of thoracolumbar vertebra and spinal canal stenosis were observed on radiology. DIAGNOSES: He was diagnosed with spondylometaphyseal dysplasia (Type A4). Gene sequencing was performed using normalized targeted regions sequencing (TRS). A novel heterozygous missense variant p.Gly139Cys in the triple-helical region. Multiple lines of evidence imply this mutation to be pathogenic. INTERVENTIONS: Posterior instrumentation and vertebral column resection were given to correct his fixed, angular thoracolumbar kyphosis. OUTCOMES: The correction was satisfying and the functional outcomes were good. LESSONS SUBSECTIONS AS PER STYLE: The findings corroborated that type X collagen plays a critical role in the formation of the human spine as well as the long bones, and further expanded the range of type X collagenopathy. Surgical procedure could be considered for patients with severe malformation and neurological impairments.

Reduced graphene oxide-supported gold dendrite for electrochemical sensing of acetaminophen.

A new nanocomposite was developed based on reduced graphene oxide (RGO) supported gold dendrite and applied for amperometric detection of acetaminophen. The RGO-gold dendrite composite was prepared by self-assembly of poly (diallyldimethylammonium chloride) (PDDA) functionalized gold dendrite and poly (sodium 4-styrenesulfonate) (PSS) functionalized RGO. The composite electrode material was characterized by Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Ultraviolet-vis spectroscopy (UV), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The RGO-gold dendrite composite exhibited enhanced conductivity, catalytic activity and stability for acetaminophen oxidation and determination. The RGO-gold dendrite based electrochemical sensor is competent for detecting acetaminophen with a linear range from 0.07 µM to 3000 µM with a detection limit of 0.005 µM (S/N = 3). Moreover, the sensor was applied for the detection of acetaminophen in tablets and urine samples, which holds great promise in pharmaceutical analysis.

Poly(3,6-diamino-9-ethylcarbazole) based molecularly imprinted polymer sensor for ultra-sensitive and selective detection of 17-ß-estradiol in biological fluids.

In this work, we reported the synthesis of 3, 6-diamino-9-ethylcarbazole and its application as a new monomer for preparation of molecularly imprinted polymer (MIP) electrochemical sensor. The as prepared MIP sensor exhibited ultrahigh sensitivity and selectivity for the detection of 17-ß-estradiol in attomolar levels (1 × 10-18molL-1). The sensor works by detecting the change of the interfacial impedance that is derived from recognition of 17-ß-estradiol on the MIP layer. The MIP sensor based on 3, 6-diamino-9-ethylcarbazole monomer revealed better performance than that of unmodified carbazole monomer. The monomer/template ratio, electropolymerization scanning cycles, and the incubation pH values were optimised in order to obtain the best detection efficiency. Under the optimised condition, the MIP sensor exhibits a wide linear range from 1aM to 10µM (1 × 10-18 ̶ 1 × 10-5molL-1). A low detection limit of 0.36aM (3.6 × 10-19molL-1) and a good selectivity towards structurally similar compounds were obtained. The proposed MIP sensor also exhibits long-term stability and applicability in human serum samples. These advantages enabled this MIP sensor to be a promising alternative of electrochemical sensor and may be extended to detection of other endogenous compounds.

Molecularly imprinted polymers on graphene oxide surface for EIS sensing of testosterone.

A novel electrochemical biosensor was developed for ultrasensitive determination of testosterone from femtomolar to micromolar levels via electrochemical impedance spectroscopy (EIS) measurements. The sensor features a nanosized molecularly imprinted polymer (MIP) film that was electrochemically grafted on a graphene-oxide sheets modified electrode. The detection mechanism of this senor is explained via the change of the interfacial impedance that derived from the recognition of the target molecule. Due to the nanosheet structure as well as the high surface area of graphene-oxide, the sensitivity of the MIP sensor is enhanced remarkably. Under an optimized condition, a wide linear range from 1fM to 1µm (1×10-15-1×10-6molL-1) and a detection limit of 0.4fM (4.0×10-16molL-1) was obtained. This composite film presented a good selectivity over structurally similar steroid hormones, and a long term stability in room temperature for the detection of testosterone. Considering these advantages, the MIP/GO electrochemical biosensor could be a substitute of testosterone immunosensor, and may be further extended to the detection of other endogenous substances.

Biomimetic sensor based on molecularly imprinted polymer with nitroreductase-like activity for metronidazole detection.

The utility of molecularly imprinted polymer (MIP) as electrochemical sensor often suffers from its limited catalytic efficiency. Here, we proposed an alternative approach by combining the concept of MIP with the use of mimetic enzyme. A metronidazole imprinted polymer with nitroreductase-like activity was successfully achieved via an electrochemical method, where melamine served two purposes: functional monomer of MIP and component of mimetic enzyme. During the imprinting process, the redox-active center, which is responsible for catalysis, was introduced into the imprinted cavities. Accordingly, the imprinted polymer, having both catalysis centers and recognition sites, exhibited enhanced electrocatalytic activity and selectivity. The sensing performances of this metronidazole imprinted biomimetic sensor were evaluated in detail. Results revealed that the response to metronidazole was linear in the concentration range of 0.5-1000 µM, and the detection limit was 0.12 µM (S/N=3). In addition, we applied the proposed sensor to detect metronidazole in an injection solution and the results implied its feasibility for practical application.

[Construction and identification of human p-selectin promotor luciferase reporter gene vector].

OBJECTIVE: To construct a luciferase reporter gene vector of p-selectin gene promoter and determine its transcriptional activity for screening the effect of drugs on the transcriptional activity of p-selectin promoter. METHODS: Primers were designed based on human p-selectin promoter sequence from UCSC software. The p-selectin promoter from human genome DNA was then amplified. After digestion of pGL3-Basic vector and p-selectin promoter with Kpn I and Xho I, p-selectin promoter was inserted into pGL3-basic vector. The recombinant plasmid, namely pGL3-p-selectin-promoter, was transiently cotransfected into 293F cells with pRL-SV40 as the control vector, and the activity of the dual luciferase was detected. The transcription activity of serially truncated segments of the p-selectin promoter reporter gene was quantified by luciferase expression. 293F cells transfected with pGL3-p-selectin-promoter reporter gene and dual luciferase were stimulated with LPS, TNF-α and As2O3, and the transcriptional activity of p-selectin promoter were assessed. RESULTS: pGL3-p-selectin-promoter was constructed successfully as verified by restriction digestion and sequence analysis. The luciferase activity was higher in pGL3-p-selectin-promoter/pRL-SV40 group than in pGL3-basic/pRL-SV40 group (0.8573±0.4703 vs 0.03955±0.05894). pGL3- 1826 bp was actively transcribed compared with pGL3-1092 bp and pGL3-3738 bp. LPS, TNF-α and As2O3 significantly enhanced the transcriptional activity of p-selectin promoter. CONCLUSION: pGL3-p-selectin-promoter can be transcribed and activated in 293F cells. This study provided an important basis for acquiring transcriptional factors and screening inflammatory factors and drugs.