Determination of VEGF165 using impedimetric aptasensor based on cyclohexanehexone-melem covalent-organic framework
TL;DR: In this article, a porous nanostructured covalent-organic framework (COF) has been prepared via condensation polymerization between the two building blocks of melem and hexaketocyclohexane octahydrate (represented as M-HO-COF).
Abstract: A porous nanostructured covalent-organic framework (COF) has been prepared via condensation polymerization between the two building blocks of melem and hexaketocyclohexane octahydrate (represented as M-HO-COF). Basic characterizations revealed that the M-HO-COF network was composed of C=N and highly conjugated aromatic moieties, along with a high surface area, large pore size, remarkable electrochemical activity, and strong bioaffinity toward aptamer strands. Given that the vascular endothelial growth factor 165 (VEGF165)-targeted aptamer was stably anchored over M-HO-COF via weak intermolecular forces, the prepared M-HO-COF network exhibited great potential as a sensitive and selective platform for the impedimetric VEGF165 aptasensor. Consequently, the M-HO-COF-based aptasensor displayed an ultralow limit of detection of 0.18 fg mL−1 within a wide range of VEGF165 concentrations from 1 fg mL−1 to 10 ng mL−1. Considering its strong fluorescence performance, excellent biocompatibility, and small nanosheet-like structure, the obtained COF-based aptasensor showed a superior sensing performance and regeneration capability after 7 regeneration cycles for the detection of osteosarcoma cells (K7M2 cells), which overexpressed with VEGF165, with a low limit of detection of 49 cells mL−1. For real f human serum samples, the obtained COF-based aptasensor exhibits acceptable mean apparent recoveries of 97.41% with a relative standard deviation of 4.60%. Furthermore, the proposed bifunctional aptasensor for the detection VEGF165 and K7M2 cells exhibited good stability, appropriate selectivity toward other biomarkers or normal cells, acceptable reproducibility, and applicability.
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TL;DR: In this paper, a comprehensive overview of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) based electrochemical aptasensors for monitoring different ultra-trace analytes (e.g. antibiotics, pesticides, and cancer markers) is provided.
Abstract: The booming development of novel porous materials, metal–organic frameworks (MOFs) and covalent–organic frameworks (COFs) has been attracting a lot of attention due to their designabilities, diversities, and extensive applications. MOFs and COFs provide a new potential opportunity and platform to fabricate electrochemical aptasensors for biosensing applications. Compared to other traditional materials, MOF/COF-based electrochemical biosensors can appreciably amplify the electrochemical response signals to improve the sensing performance. Herein, we provide a comprehensive overview of MOF/COF-based electrochemical aptasensors for monitoring different ultra-trace analytes (e.g. antibiotics, pesticides, and cancer markers). This review systematically discusses the classification of electrochemical aptasensors based on various functional materials, including pure MOFs, MOF/conductive composites, metal nanoparticle/MOF composites, pure COFs, COFs/conductive composites, and other hybrid materials. Furthermore, some typical MOF/COF-based electrochemical aptasensors in the recognition of specific targets are described in detail to improve and guide further research for biosensing applications.
23 citations
TL;DR: In this article , a microfluidic sensing chip that integrates a centrifugal separation pretreatment unit and a composite nanosensing film was proposed for the rapid and sensitive detection of vascular endothelial growth factor 165 (VEGF165) in clinical blood samples.
Abstract: For the rapid and sensitive detection of vascular endothelial growth factor 165 (VEGF165) in clinical blood samples, a microfluidic sensing chip that integrates a centrifugal separation pretreatment unit and a composite nanosensing film was proposed in this paper. An efficient sensing strategy and method was established. The blood sample was first separated and extracted by centrifugal force on the centrifugal microfluidic chip within 5 min after injection. The separated plasma can be automatically transferred through the designed microchannels to the detection area integrated electrodes for subsequent differential pulse voltammetric detection. The Au NPs/MCH/Apt2 sensing film was constructed on the surface of the Au working electrode. A sandwich sensing strategy based on "double aptamers" and "nanoprobe" for VEGF165 detection was established, by which the synthetic Apt1/PThi/Au NP nanoprobe was applied to capture VEGF165 in plasma and bind to the sensing film. By this method, the detection limit of VEGF165 in whole blood was 0.67 pg/mL and the linear range was between 1 pg and 10 ng, which met the needs of clinical VEGF165 detection. It was illustrated that the proposed methodology based on the centrifugal microfluidic chip had potential application prospects in the development of the point-of-care testing fields.
9 citations
TL;DR: Covalent organic frameworks (COFs) as discussed by the authors are crystalline organic polymers with programmable topological architectures using properly predesigned building blocks precursors, which can be used for different applications, such as the development of electrochemical sensors and biosensors.
Abstract: Covalent organic frameworks (COFs) are defined as crystalline organic polymers with programmable topological architectures using properly predesigned building blocks precursors. Since the development of the first COF in 2005, many works are emerging using this kind of material for different applications, such as the development of electrochemical sensors and biosensors. COF shows superb characteristics, such as tuneable pore size and structure, permanent porosity, high surface area, thermal stability, and low density. Apart from these special properties, COF’s electrochemical behaviour can be modulated using electroactive building blocks. Furthermore, the great variety of functional groups that can be inserted in their structures makes them interesting materials to be conjugated with biological recognition elements, such as antibodies, enzymes, DNA probe, aptamer, etc. Moreover, the possibility of linking them with other special nanomaterials opens a wide range of possibilities to develop new electrochemical sensors and biosensors.
7 citations
TL;DR: Covalent organic frameworks (COFs) have gained tremendous interest in cancer therapy owing to their multifunctional properties, such as biocompatibility, tunable cavities, excellent crystallinity, ease of modification/functionalization, and high flexibility as mentioned in this paper .
TL;DR: In this paper , the authors reviewed the flagged recent research (2021-2023) developed as a series of biosensors equipped with nanomaterials and aptamer sequences (nanoaptasensors) to diagnose/prognosis of various types of cancers.
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TL;DR: Recently, an anti-VEGF antibody (bevacizumab), when used in combination with chemotherapy, was shown to significantly improve survival and response rates in patients with metastatic colorectal cancer and thus, validate VEGF pathway inhibitors as an important new treatment modality in cancer therapy.
Abstract: New blood vessel formation (angiogenesis) is a fundamental event in the process of tumor growth and metastatic dissemination. Hence, the molecular basis of tumor angiogenesis has been of keen interest in the field of cancer research. The vascular endothelial growth factor (VEGF) pathway is well established as one of the key regulators of this process. The VEGF/ VEGF-receptor axis is composed of multiple ligands and receptors with overlapping and distinct ligand-receptor binding specificities, cell-type expression, and function. Activation of the VEGF-receptor pathway triggers a network of signaling processes that promote endothelial cell growth, migration, and survival from pre-existing vasculature. In addition, VEGF mediates vessel permeability, and has been associated with malignant effusions. More recently, an important role for VEGF has emerged in mobilization of endothelial progenitor cells from the bone marrow to distant sites of neovascularization. The well-established role of VEGF in promoting tumor angiogenesis and the pathogenesis of human cancers has led to the rational design and development of agents that selectively target this pathway. Studies with various anti-VEGF/VEGF-receptor therapies have shown that these agents can potently inhibit angiogenesis and tumor growth in preclinical models. Recently, an anti-VEGF antibody (bevacizumab), when used in combination with chemotherapy, was shown to significantly improve survival and response rates in patients with metastatic colorectal cancer and thus, validate VEGF pathway inhibitors as an important new treatment modality in cancer therapy.
2,699 citations
TL;DR: In this article, the authors present a set of performance criteria for single-use biosensors, i.e., a device that is both disposable after one measurement, and unable to monitor the analyte concentration continuously or after rapid and reproducible regeneration.
1,267 citations
TL;DR: This work reviews findings used to establish the well-known mosaic structure model for the EEI (often referred to as solid electrolyte interphase or SEI) on negative electrodes including lithium, graphite, tin, and silicon and suggests ways to tailor EEI layer composition and properties.
Abstract: Understanding reactions at the electrode/electrolyte interface (EEI) is essential to developing strategies to enhance cycle life and safety of lithium batteries. Despite research in the past four decades, there is still limited understanding by what means different components are formed at the EEI and how they influence EEI layer properties. We review findings used to establish the well-known mosaic structure model for the EEI (often referred to as solid electrolyte interphase or SEI) on negative electrodes including lithium, graphite, tin, and silicon. Much less understanding exists for EEI layers for positive electrodes. High-capacity Li-rich layered oxides yLi2–xMnO3·(1–y)Li1–xMO2, which can generate highly reactive species toward the electrolyte via oxygen anion redox, highlight the critical need to understand reactions with the electrolyte and EEI layers for advanced positive electrodes. Recent advances in in situ characterization of well-defined electrode surfaces can provide mechanistic insights an...
752 citations
TL;DR: Overall, worldwide osteosarcoma incidence rates were quite similar in the younger age groups, but the greatest variation in incidence rates was observed in the elderly.
Abstract: Osteosarcoma incidence rates in the United States peak in adolescence and in the elderly. The international patterns of osteosarcoma incidence in children have been described, whereas those for young, middle age or elderly adults have not. Using the Cancer Incidence in Five Continents, International Agency for Cancer Research database we compared incidence rates for children and adolescents (age 0-24 years), the middle age group (25-59 years) and elderly (>or=60 years) persons by world regions and individual countries. Overall, worldwide osteosarcoma incidence rates were quite similar in the younger age groups. The greatest variation in incidence rates was observed in the elderly.
527 citations
TL;DR: It is anticipated that the future of osteosarcoma treatment will involve treatment tailored to the molecular profile of tumours at diagnosis, adjuvant therapy directed towards dysfunctional molecular pathways rather than the use of cytotoxics, and a more standardised approach to the measurement of clinical prognostic factors.
Abstract: Traditional prognostic determinants in osteosarcoma have included demographics (age, sex), tumour size, site, stage, and the response to chemotherapy Many of these are determined using varying techniques and units of measurement, which can make comparison between studies difficult The absence of survival difference between limb sparing surgery and amputation has been repeatedly demonstrated in primary disease, and even in the setting of pathological fracture On the other hand, there is still some controversy over the existence of increased local recurrence for limb-sparing surgery, and the implications of this Commonly used prognostic determinants such as metastases, and response to chemotherapy enable a high degree of prognostic accuracy but usually at a late stage in the course of disease Leading on from this, there is a need to uncover molecular pathways with specific influence over osteosarcoma progression to facilitate earlier treatment changes Some important pathways are already being defined, for example the association of CXCR4 with metastases on presentation, the likelihood of doxorubicin resistance with positive P-glycoprotein, and the reduced survival prediction of over expressed survivin It is anticipated that the future of osteosarcoma treatment will involve treatment tailored to the molecular profile of tumours at diagnosis, adjuvant therapy directed towards dysfunctional molecular pathways rather than the use of cytotoxics, and a more standardised approach to the measurement of clinical prognostic factors
237 citations