One pressing concern today is to construct sensors that can withstand various disturbances for highly selective and sensitive detecting trace analytes in complicated samples. Molecularly imprinted ...polymers (MIPs) with tailor-made binding sites are preferred to be recognition elements in sensors for effective targets detection, and fluorescence measurement assists in highly sensitive detection and user-friendly control. Accordingly, molecular imprinting-based fluorescence sensors (MI-FL sensors) have attracted great research interest in many fields such as chemical and biological analysis. Herein, we comprehensively review the recent advances in MI-FL sensors construction and applications, giving insights on sensing principles and signal transduction mechanisms, focusing on general construction strategies for intrinsically fluorescent or nonfluorescent analytes and improvement strategies in sensing performance, particularly in sensitivity. Construction strategies are well overviewed, mainly including the traditional indirect methods of competitive binding against pre-bound fluorescent indicators, employment of fluorescent functional monomers and embedding of fluorescence substances, and novel rational designs of hierarchical architecture (core-shell/hollow and mesoporous structures), post-imprinting modification, and ratiometric fluorescence detection. Furthermore, MI-FL sensor based microdevices are discussed, involving micromotors, test strips and microfluidics, which are more portable for rapid point-of-care detection and in-field diagnosing. Finally, the current challenges and future perspectives of MI-FL sensors are proposed.
•Molecular imprinting based fluorescence sensors (MI-FL sensors) are reviewed.•Sensing principle and signal transduction mechanisms are introduced.•General and novel construction strategies for MI-FL sensors are summarized.•MI-FL sensor based microdevices are overviewed.•The present challenges and perspectives of MI-FL sensors are proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The development of responsive antibacterial implants is highly significant for the treatment of implant‐associated infection. In this study, one self‐adaptive antibacterial porous implant with ...sustainable responses is flexibly designed and constructed for infected bone defect therapy. Porous hydroxyapatite (HA) implants derived from nature bones, one typical implant, are first functionalized via low‐cytotoxic ethanediamine‐functionalized poly(glycidyl methacrylate) brushes, and gentamicin sulfate (GS, a kind of aminoglycoside antibiotic in clinic) is subsequently conjugated by an acid‐responsive bond to produce smart antibacterial HA implants (HA–GS). The release of GS can be triggered by the acidic environment induced by the metabolism of bacteria for self‐adaptive antibacterial response. Due to the good drug loading capacity and chemical stability of HA–GS in neutral condition, the sustainable antibacterial ability is readily achieved for long‐term applications. The highly effective in vivo anti‐infection therapy with HA–GS is demonstrated in one infected bone defect rabbit model. The implant‐associated infection is completely inhibited by HA–GS at the early stage and the defected bones exhibit superior recovery at the late stage. This design strategy of sustainable self‐adaptive antibacterial implants will provide a promising concept for the prevention and therapy of implant‐associated infections.
Self‐adaptive antibacterial porous implants (HA–GS) with sustainable responses are readily designed and constructed for the high‐performance therapy against infected bone defects.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this work, we have developed an electrochemical aptasensor for high-sensitivity determination of carcinoembryonic antigen (CEA) based on lead ion (Pb2+)-dependent DNAzyme-assisted signal ...amplification and graphene quantum dot-ionic liquid-nafion (GQDs-IL-NF) composite film. We designed hairpin DNA containing CEA-specific aptamers and DNAzyme chains. In the presence of CEA, hairpin DNA recognized the target and performed a DNAzyme-assisted signal amplification reaction to yield a large number of single-stranded DNA. The GQDs-IL-NF composite film was immobilized on the glassy carbon electrode for the interaction with single-stranded DNA through noncovalent π-π stacking interaction. Therefore, the methylene blue-labeled substrate DNA (MB-substrate) was fixed on the electrode and exhibited an initial electrochemical signal. Under optimal conditions, the response current change was proportional to the concentration of CEA, demonstrating a wide linear range from 0.5fgmL−1 to 0.5ngmL−1, with a low detection limit of 0.34fgmL−1. Furthermore, the proposed aptasensor was successfully applied in determining CEA in serum samples, showing its superior prospects in clinical diagnosis.
•Pb2+dependent DNAzyme electrochemical biosensor for carcinoembryonic antigen detection was developed.•The graphene quantum dots-ionic liquid-nafion composite film was fabricated on electrode for the first time.•The target-aptamer complex recycling led to continuous cleavage of substrate chain and amplified electrochemical signal.•The method has been applied in human serum, with high selectivity and good recovery.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Modulating effector immune cells via monoclonal antibodies (mAbs) and facilitating the co-engagement of T cells and tumor cells via chimeric antigen receptor- T cells or bispecific T cell-engaging ...antibodies are two typical cancer immunotherapy approaches. We speculated that immobilizing two types of mAbs against effector cells and tumor cells on a single nanoparticle could integrate the functions of these two approaches, as the engineered formulation (immunomodulating nano-adaptor, imNA) could potentially associate with both cells and bridge them together like an 'adaptor' while maintaining the immunomodulatory properties of the parental mAbs. However, existing mAbs-immobilization strategies mainly rely on a chemical reaction, a process that is rough and difficult to control. Here, we build up a versatile antibody immobilization platform by conjugating anti-IgG (Fc specific) antibody (αFc) onto the nanoparticle surface (αFc-NP), and confirm that αFc-NP could conveniently and efficiently immobilize two types of mAbs through Fc-specific noncovalent interactions to form imNAs. Finally, we validate the superiority of imNAs over the mixture of parental mAbs in T cell-, natural killer cell- and macrophage-mediated antitumor immune responses in multiple murine tumor models.
Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. Through the development of a drug delivery system that tethers doxorubicin onto the surface of gold ...nanoparticles with a poly(ethylene glycol) spacer via an acid-labile linkage (DOX-Hyd@AuNPs), we have demonstrated that multidrug resistance in cancer cells can be significantly overcome by a combination of highly efficient cellular entry and a responsive intracellular release of doxorubicin from the gold nanoparticles in acidic organelles. DOX-Hyd@AuNPs achieved enhanced drug accumulation and retention in multidrug resistant MCF-7/ADR cancer cells when it was compared with free doxorubicin. It released doxorubicin in response to the pH of acidic organelles following endocytosis, opposite to the noneffective drug release from doxorubicin-tethered gold nanoparticles via the carbamate linkage (DOX-Cbm@AuNPs), which was shown by the recovered fluorescence of doxorubicin from quenching due to the nanosurface energy transfer between the doxorubicinyl groups and the gold nanoparticles. DOX-Hyd@AuNPs therefore significantly enhanced the cytotoxicity of doxorubicin and induced elevated apoptosis of MCF-7/ADR cancer cells. With a combined therapeutic potential and ability to probe drug release, DOX-Hyd@AuNPs represent a model with dual roles in overcoming MDR in cancer cells and probing the intracellular release of drug from its delivery system.
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IJS, KILJ, NUK, PNG, UL, UM
Background
The present study aimed to explore the differences between apical pulp‐derived cells of deciduous teeth (De‐APDCs) and apical pulp‐derived cells of permanent teeth (P‐APDCs)/dental pulp ...cells from exfoliated deciduous teeth (De‐DPCs).
Methods
Three types of cells (De‐DPCs, P‐APDCs and De‐APDCs) were cultured by the tissue explant method. Transcriptome sequencing for the three types of cells was conducted and the differentially expressed genes (DEGs) between groups were selected. The potential biological functions and pathways enriched by the DEGs were analyzed.
Results
There were 35 up‐ and 21 down‐regulated DEGs in P‐APDC versus the De‐APDC comparison group, and 328 up‐ and 976 down‐regulated DEGs in De‐APDC versus De‐DPC. The DEGs in the P‐APDC versus De‐APDC group were significantly enriched in biological process terms associated with extracellular matrix organization, and regulation of cell proliferation and the pathway of cell adhesion molecules. Additionally, the DEGs between De‐APDC and De‐DPC were involved in functions related to extracellular matrix organization and the regulation of bone remodeling, as well as the pathway of extracellular matrix‐receptor interaction.
Conclusions
There were fewer differences between P‐APDC and De‐APDC compared to between De‐APDC and De‐DPC in view of the total number of DEGs. Differences in function existed relating to extracellular matrix organization among the three cells. P‐APDCs and De‐APDC had different functions on cell proliferation and adhesion. De‐APDCs may also act as a unique stem cell resource for tissue engineering.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this article, a robust trajectory tracking control method is proposed for the passive gait training exoskeleton system driven by pneumatic muscles (PMs). Conventional model-based controllers ...suffer from limitations with respect to model uncertainties and external disturbances caused by PMs and complex robotic systems. An echo state network (ESN) is used in this study to approximate the model uncertainties and external disturbances of the exoskeleton system. Based on the approximation of ESN, a super-twisting control (STC) algorithm is designed to guarantee accurate tracking control at both hip and knee joint levels. Because there are both weight error and global approximation error in neural network approximation, a standard quadratic form cannot be obtained which plays an important role in the stability analysis of the traditional super twisting algorithm. To solve this issue, a dedicated positive definite matrix is constructed in this article, which bridges the ESN and STC by providing a parameter selection criteria. The stability with respect to the tracking problem of the exoskeleton system is then guaranteed according to the Lyapunov theorem. Both numerical simulations and experimental results present better tracking accuracy and robustness compared with the traditional sliding mode control and STC.
Precise control of a pneumatic muscle actuator is a challenging problem, due to its nonlinear and time-varying characteristics. Specifically, it can be modeled as parallel connection of a nonlinear ...friction force, a nonlinear spring, and a nonlinear contractile element. It is difficult to identify the coefficients associated with these elements within a certain precision as they change along the course of continuous use. In this paper, we introduce a novel adaptive servomechanism controller and rigorously prove that the trajectory tracking can be achieved with a desirable error bound. Moreover, an experiment platform is set up to demonstrate the effectiveness of the proposed controller in real applications. In particular, the proposed adaptive controller significantly improves the tracking accuracy and achieves better performance than nonadaptive and PID controllers and other existing controllers in the literature.
Bacteria‐Responsive Multifunctional Nanogel: We developed a bacteria‐responsive multifunctional nanogel for targeted antibiotic delivery, in which bacterial enzymes are utilized to trigger antibiotic ...release by degrading the polyphosphoester core. The mannosylated nanogel preferentially delivers drugs to macrophages and leads to drug accumulation at bacterial infection sites through macrophage transport. This nanogel provides macrophage targeting and lesion site‐activatable drug release properties, which enhances bacterial growth inhibition.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In pneumatic muscle actuators (PMAs)-driven robotic applications, there might exist unpredictable shocks which lead to the sudden change of desired trajectories and large tracking errors. This is ...dangerous for physical systems. In this article, we propose a novel adaptive proxy-based robust controller (APRC) for PMAs, which is effective in realizing a damped response and regulating the behaviors of the PMA via a virtual proxy. Moreover, the integration of the APRC and the nonlinear disturbance observer further handles the system uncertainties/disturbances and improves the system robustness. According to the Lyapunov theorem, the tracking states of the closed-loop PMA control system are proven to be globally uniformly ultimately bounded through two motion phases. Extensive experiments are conducted to verify the superior performance of our approach, in multiple tracking scenarios.
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