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In the context of rapid aging, "empty nest syndrome" is becoming a major public health concern. The causal effects of empty nest on depressive symptoms have been studied in developed countries, but the mediating mechanism of depressive symptoms in the association between empty nest and cognitive impairments has not been studied. This study estimated the causal association of empty nest with depressive symptoms and cognitive impairments in China, and then estimated how depression mediates the association between empty nest and cognitive impairments.Using data of 23,614 urban older adults (65+) obtained from the Shandong Province Aging and Mental Health Survey in 2020, a weighted linear regression model combined with instrumental variable was applied to explore the causal effects of empty nest, and a four-step mediation model was run to test the mediator of depressive symptoms. The Ascertain Dementia 8-item Questionnaire and Patient Health Questionnaire-9 were used to measure cognitive impairments and depressive symptoms.Empty nest was associated with 0.13 (95%CI: 0.04-0.23) and 0.23 (95%CI: 0.14-0.33) increases in the Ascertain Dementia 8-item Questionnaire and the Patient Health Questionnaire-9 scores, respectively. The association between empty nest and the Ascertain Dementia 8-item Questionnaire scores was mediated by the Patient Health Questionnaire-9 scores.Empty nest affected depression in adulthood with cognitive impairments. A focus on integrative intervention for empty nesters is recommended, taking depression and cognition into account.It is a cross-sectional study and the data is not nationally representative.

Trichinellosis is caused by Trichinella spiralis, a meat-borne zoonotic disease transmitted to humans through the consumption of infected undercooked or raw meat. Surveillance using safe and precise diagnostic tools to diagnose T. spiralis in sheep is needed to assess the incidence and probability of transmission from sheep to humans. In this study, we developed a real-time PCR assay to detect T. spiralis DNA in ovine muscle samples that can be used as an alternative surveillance tool to ensure food safety using newly designed primers. The assay is specific for the Scfld4 gene of Trichinella (T1) and enables the detection of larvae in ovine muscle tissue samples with high sensitivity and specificity. Trichuris ovis, Oesophagostomum dentatum, Haemonchus contortus, and Bunostomum trigonocephalum showed no nonspecific amplification. The assay could detect Trichinella DNA concentrations as low as 0.0026 ng/μL, equivalent to 0.0064 larvae, indicating a high sensitivity for T. spiralis detection. We used this real-time PCR to detect 73 ovine muscle samples from an ovine abattoir, and five samples tested positive via real-time PCR but negative via microscopy. This assay may provide a more specific and sensitive method for rapidly detecting Trichinella larvae in ovine muscle tissues.

Present work investigated the use of Cold Metal Transfer (CMT) welding for additive manufacturing of copper‑aluminum alloys with addition of silicon in small amount. The additive manufacturing was successfully demonstrated through two samples with the 4.34% (sample-1) and 6.58% (sample-2) aluminum content, which is not much different with the content of the design. The analyses of performance of samples reveal that both samples have good strength and ductility. It is also found addition of silicon in small amount (2.1%–2.4%) effectively improves hardness, tensile strength and 0.2% offset Yield Strength in comparison to pure copper‑aluminum alloy. The results of X-ray diffraction (XRD), showed that sample-2 possessed CuAl2 with different crystal structure whereas sample-1 did not. It is found that an increase in aluminum caused both tensile strength and 0.2% offset Yield Strength to increase, however, increase in yield strength was very significant (155 MPa i.e. 38% more than that of Sample-1). In this study, the 0.2Pct offset Yield Strength of sample-1 is 150 MPa more than that of sample-2.

The construction of a photoelectrochemical (PEC) strategy for multi-component detection represents a great challenge in the field of sensing. To address these challenges, herein we presented a hollow-channel paper-based PEC analytical platform based on chemiluminescence (CL) addressable strategies excited PEC strategy for multiplexed sensing application. Sandwich-structured CdS quantum dots (QDs)/reduced graphene oxide (RGO)/ZnO nanorods arrays (NRAs) heterostructure where CdS serves as visible light sensitizers, RGO acts as an electron relay between ZnO NRAs and CdS QDs, were simply assembled on the gold nanoparticles modified paper working photoelectrode (Au-PWE). The PEC performance of the CdS/RGO/ZnO can be greatly improved benefiting from the formation of type II band alignment between CdS QDs and ZnO NR as well as the super charge collection and shuttling property of RGO. Multiplexed CL emission could be achieved through controlling the CL co-reagents transport. By the virtue of CL addressable technique and the excellent PEC activity of CdS/RGO/ZnO, a highly sensitive, and selective multiple microRNAs (miRNAs) quantification method was achieved. Such a tailored strategy would break the bottleneck of the current PEC detection techniques in multiplex tracing, as well as serve as a novel concept for designing multi-channel PEC sensing method.

The photoelectrochemical (PEC) technique has resulted in substantial progress in chemical sensing applications. However the complicated photoelectrode modification procedures would enable undesired background noise and decreasing sensitivity. Hence, it is important to explore a new approach alternative to inconvenient substrate modification. Herein, inspired by the stimuli-responsive drug delivery systems, an innovative PEC system is developed for efficiently microRNA-21 (miRNA-21) tracing. Hierarchical nanocomposites based on hematite (α-Fe2O3) coated self-ordered titanium dioxide nanorod arrays (TiO2 NRAs) exhibited enhanced response to solar light, promoted charge carrier separation and transfer efficiency was adopted as photoelectrode directly. Functional mesoporous silica nanomaterial (MSN) is prepared as nanocarriers for efficient loading of Cu2+, further capped with miRNA-21 responsive capture RNA probe. Thereafter, the capture RNA probe endows the functional MSN with responsiveness to miRNA-21. With the presence of miRNA-21, this system is thus triggered and a quickly release of capped Cu2+ occurs due to the dissociation of capture RNA probe presented on the MSN surface via base-pair hybridization. The released Cu2+ was then served as electron acceptor reduced to Cu° at the counter electrode to enhance electron-hole pair separation efficiency, leading to a promoted photocurrent response. Consequently, the miRNA-21 can be accurately quantified. Taking advantage of its sensitivity and specificity, this versatile strategy demonstrates a new route for the design PEC sensing approach without any photoelectrode modification procedure, and holds great potential for biosensing and clinical diagnosis.

Rational design of photoelectrode architectures is deemed as an effective solution to enhance efficiency of photoelectrochemical water splitting for conquering increasingly prominent environmental problems. Herein, a programmable flexible photoanode with built-in tandem Z-scheme configuration fabricated by in-situ growth of MoSe2-CdS-ZnO array with ultrathin nanosheet-interlaced-nanorod structure on the Au paper electrode, is firstly reported. By taking advantages of the interwoven nanonetwork structure, high conductivity as well as larger porosity of the as-fabricated Au paper electrode, a stable light-harvesting paper chip with fast transfer/separate mediators of the charge/carriers is thus integrated. By virtue of double internal electric fields (IEFs) and photothermal effect, the developed MoSe2-CdS-ZnO photoanode exhibits incident-photon-to-current efficiency of 52 % under 460 nm of light irradiation, and the current density reaches 2.4 mA cm−2 at 0.3 V versus normal hydrogen electrode, which is comparable with respect to current state-of-the-art “type-II-scheme”, “surface-scheme”, and cocatalyst-free photocatalysts (0.03–2.4 mA cm−2). Consequently, the paper-based photoanode achieves admirable photoelectrocatalytic hydrogen generation property (39.7 μmol cm−2 h-1). The synergistic effect of tailorable tandem Z-scheme configuration with double IEFs and delineating of 3D cross-linked network structure of the proposed photoanode in this work may open an avenue for constructing high-performance photoelectrochemical water splitting devices.

In this work, the microstructure of CoCrFeNiTa0.4 based high entropy alloy was studied. HEAs with the same structure were prepared successfully by replacing Ta with relatively less expensive Nb (Ta0.2Nb0.1, Ta0.2Nb0.3, Ta0.2Nb0.5 replacing Ta0.4) using powder plasma arc additive manufacturing (PPA-AM), an emerging AM technology. The microstructural phases, phase hardness and mechanical properties of CoCrFeNiTa0.4 and CoCrFeNiTa0.2Nb0.1-0.5 have been analyzed. From this investigation, it is evident that the CoCrFeNiTa0.2Nb0.3 alloy can replace CoCrFeNiTa0.4 alloy with improved structure and mechanical properties along with a cost saving of 29%. This is also the first report to demonstrate the microstructure - mechanical properties relationship in CoCrFeNiTaNb high entropy alloy.

Current photoelectrochemical (PEC) sensing system usually suffers from false-positive readout caused by the environmental factor. Herein, a PEC sensing platform with wide spectrum responsive based on exciton-plasmon interactions gated energy transfer between photoelectrode and Au NPs was designed for ultrasensitive detection of adenosine by coupling with self-checking function. Specifically, 2D black phosphorus (BP) nanosheets sensitized nanoporous BiVO4 (BiVO4-BP) acted as photoelectrode could harness light from ultraviolet to near infrared and accelerate charge separation, thus obviously promoted PEC performance. The detection mechanism was designed by controlling exciton-plasmon interaction on the influence of energy transfer between photoelectrode and dispersed Au NPs. Taking advantage of the disaggregation of Au NPs aggregates upon the addition of adenosine, which leads to a shift in the plasmonic band of the Au NPs accompanied by a color change of the solution from blue to purplish red enables a naked-eye readout semiquantitation of the adenosine. Meanwhile, the plasmonic shift gates the photocurrent response of photoelectrode for accurate quantitation of the adenosine exposure ranged from 0.1 nM to 1 μM with acceptable reliability. Enabled by the unique mechanism, this approach provides a new horizon for designing multi-functional PEC sensing platform.

A novel microfluidic paper-based colorimetric sensor for the detection of bisphenol A (BPA) was developed based on the intrinsic peroxidase activity of ZnFe2O4 magnetic nanoparticles (ZnFe2O4 MNPs) and the adsorption capacity of molecularly imprinted polymer (MIP) membranes. In the process, ZnFe2O4 MNPs and cellulose fibers in paper were wrapped by MIP membranes (ZnFe2O4@MIP membranes) successfully. Novel MIP membranes for the recognition of BPA were prepared in polar solvent using acrylamide as the functional monomer and BPA as the template by bulk polymerization, which resulted in a new type of BPA imprinted polymer membranes. Adsorption isotherms model of MIP membranes was employed to describe the isotherms, and maximum adsorption capacity was evaluated. In the presence of 3,3′,5,5′-tetramethylbenzidine (TMB), the as-prepared ZnFe2O4 MNPs peroxidase mimetics was used to catalyze chromogenic reactions and showed the color with respective intensity. Under optimized conditions, the grey intensity was found to be proportional to the BPA concentrations in the range of 10 nM–1000 nM (R2 = 0.9945) with a detection limit of 6.18 nM. With the advantages of highly reproducible response, good selectivity and excellent regeneration, the colorimetric sensor holds great potential for portable detection of targets in environmental monitoring, security inspection and complicated matrices.

This work described that one–step synthesis three dimensional anatase hierarchically cactus–like TiO 2 arrays (AHCT) and their application in constructing a novel photoelectrochemical (PEC) and visualized sensing platform based on molecular imprinting technique, which reports its result with the prussian blue (PB) electrode served as the electrochromic indicator for the detection of glycoprotein (RNase B). The AHCT arrays were perpendicularly grown on FTO substrate with tunable sizes, offering many advantages, such as large contact area, rapid charge electron separation and transport. A possible formation process of the interesting AHCT arrays has been investigated based on time–dependent experiment. In addition, the PEC and visualized sensing platform was constructed based on the molecularly imprinted polymer modified AHCT arrays. Specifically, in the proposed system, the more RNase B being, the more insulating layer was formed on the surface of AHCT arrays that impeded the harvesting of light and electron transfer, resulting in the reduction of photocurrent. When upon light illumination, the photogenerated electrons flow through an external circuit to PB, leading to the reduction of PB to prussian white (PW), which is transparent. The rate of decolourization of PB is proportional to the concentration of RNase B. In this way, a visualized PEC sensing platform that gives its quantitative information could be performed by monitoring the change of color intensity. Under optimal conditions, the protocol possessed a detection range of 0.5 pM to 2 μM (r=0.997) and the limit of detection was 0.12 pM toward RNase B. Our method eliminates the need for sophisticated instruments and high detection expenses, making it possible to be a reliable alternative in resource–constrained regions.

By incorporating the Prussian Blue (PB) electrochromic display as cathode, a solar-driven photoelectrochemical (PEC) cell was constructed through combining sandwich-structured graphite-like carbon nitride (g-C3N4)-Au-branched-titanium dioxide (B-TiO2) nanorods as photoanode for self-powered hydrogen peroxide (H2O2) sensing, which exhibits both direct photoelectrochemical and electrochromic response. The gold nanoparticles (Au NPs) sandwiched between the B-TiO2 nanorods and the g-C3N4 layer served as electron relay as well as plasmonic photosensitizer to enhance the solar-to-chemical energy conversion efficiency. Owing to the effective disproportionation of H2O2 and specific recognition of mannose on cell surface, concanavalin-A conjugated porous AuPd alloy nanoparticles were introduced as the catalytically active nanolabels promoting generation of hydroxyl radicals (·OH). Based on the cleavage of DNA with the participation of ·OH radicals generated by the decomposition of H2O2 under the catalysis of AuPd alloy result in the disassembly of cancer cells to achieve further signal enhancement. The multiple-signal-output sensing response not only provides a promising strategy for different analytical purposes based on novel stimuli-responsive materials, but also enhances the reliability in the analyte detection.

In this study, based on in situ generation of CdS quantum dots (QDs) on the surface of branched TiO2 (B-TiO2) nanorods, an solar innovative photoelectrochemical (PEC) sensing platform was constructed for real-time, and sensitive detection of cellular H2S. Specifically, B-TiO2 nanorods arrays consisting of TiO2 nanorods directly grown on fluorine-doped tin oxide (FTO) further using TiCl3 mediated surface treatment of TiO2 nanorods are designed and fabricated as a new type of photoelectrode. CdS quantum dots (QDs) was formed on the surface of B-TiO2 nanorods arrays through the reaction between Cd2+ and S2-. And a significant enhancement in the photocurrent was obtained that ascribed to the formation of CdS-B-TiO2 heterostructures, thus leading to sensitive PEC recording of the H2S level in buffer and cellular environments. By using Prussian blue (PB) a electrochromic material to capture the photoelectron generated from the photoelectrode, a new visual system was proposed due to the formation of Prussian white (PW), which could be used to visualize the quantum photoelectric effect. This novel PEC sensing platform not only achieved satisfied analysis results toward S2-, but also showed excellent sensitivity, selectivity, low cost, and portable features. The strategy through the in situ generation of semiconductor nanoparticles on the surface of wide band-gap semiconductor paves the way for the improvements of PEC analytical performance. Meanwhile, the quantitative read-out electrochromic display paves a facile avenue and initiates new opportunities for creation of cheap, miniaturization sensors for other relevant analytes.

As a nondegradable environmental pollutant, lead ion (Pb2+) has been proven to be deleterious for environmental and health. Conveniently, quickly and accurately on-site detection of Pb2+ is of paramount importance. Herein, an electrochemiluminescence (ECL) assay protocol using two-dimensional black phosphorus (2D BP) nanoflakes as new ECL emitter for highly sensitive and selective trace Pb2+ was designed on the basis of Pb2+ induced ECL resonance energy transfer (ECL-RET) between 2D BP nanoflakes and Ag/AgCl nanocubes. Anodic green ECL emission of BP nanoflakes without any coreactants was achieved. It is noteworthy that the possible ECL mechanism and the influence of coreactants on the ECL behaviour of BP nanoflakes were further investigated. Benefitting from the well match between the ECL emission spectrum of BP nanoflakes (∼510 nm) and the absorption spectrum of Ag/AgCl nanocubes (200-300 nm and 400-700 nm), effective energy transfer yielded. The introduction of Pb2+ would lead to the detachment of Ag/AgCl nanocubes then result in an enhanced ECL emission. Based on this, the proposed method could accurately quantify the Pb2+ in the range from 0.5 pM to 5 nM, which exhibited comparative performance to previous work. Furthermore, this study presents the example of employing 2D BP nanoflakes as ECL emitters and constructing a coreactant-free ECL sensing platform, which might open up a promising route for the potential design and implement in clinical analysis.

The Yangtze River Delta white goat is a sole goat species that can naturally produce superior-quality brush hair. It's worth to mention that study the developmental mechanism of goat hair follicle stem cells is vital for future breed preservation and molecular breeding. In this study, we successfully isolated hair follicle stem cells from the skin tissue of fetal sheep neck spine, and harvested superior-quality and normal-quality brush hair goat tissue. The expression of miR-31-5p in goat hair follicle stem cells was verified by qPCR and Western blot. The effects of overexpression or inhibition of miR-31-5p on the proliferation and apoptosis of hair follicle stem cells were detected by EdU, CCK-8, flow cytometry, etc. miR-31-5p can significantly improve cell proliferation and inhibit cell apoptosis by targeting RASA1 and upregulating MAP3K1 level, whereas miR-31-5p knockdown led to an opposite effect. These results reveal a miR-31-5p-associated regulatory network between miR-31-5p and RASA1/MAP3K1 during the progression of superiorquality brush hair traits.

This paper investigates a completely distributed adaptive formation control protocol for networked quadrotors under switching communication topologies, where the dynamics of each quadrotor involves seriously nonlinearity and uncertainty simultaneously. For the switching communication topologies case, the adaptive formation control protocol is proposed to guarantee that the translational and rotational tracking errors of the global closed-loop system can converge into a priori set neighborhood of the origin ultimately. Furthermore, the proposed formation control protocol is completely distributed, which means that the controller of each quadrotor only needs the information from itself and its neighbors. Numerical simulation results on the quadrotor team are provided to confirm the effectiveness and advantages of the proposed adaptive formation control protocol.

The hybrids, N -aminobutyl- N -ethylisoluminol (ABEI), horseradish peroxidase (HRP) and cancer antigen 125 s antibody (Ab2) immobilized graphene oxide (GO), were prepared, which exhibited excellent chemiluminescence (CL) activity. The zinc oxide nanorods (ZNRs) grew on reduced graphene oxide (RGO) modified paper working electrode (ZNRs-RGO/PWE) via an in situ growth method. The deposition of CdS quantum dots (QDs) on ZNRs/RGO-PWE resulted in an enhanced excitation and photo-to-electric conversion efficiency. The ABEI-GO@HRP/Ab2CL system was employed as an internal excited light source. A photoelectrochemical (PEC) immunosensor based on CdS-sensitized ZNRs anchored RGO as the photoactive matrix and ABEI-GO@HRP/Ab2 as the CL labels was established for sensitive detection of cancer antigen 125 (CA 125). As a model, sandwich CA 125-antibody was taken as molecular reorganization elements on this sensor for the sensitive determination of CA 125 in the linear range from 5.0 × 10 −4 U/mL to 500 U/mL with a detection limit of 2.0 × 10 −4 U/mL. The specificity, reproducibility, and stability of this sensor were also investigated. This proposed method might be attractive for clinical and biomedical applications.

In this work, a novel sensing platform based on visible light driven biofuel cell (BFC) has been facilely designed for sensitive detection of prostate-specific antigen (PSA) with the photo-response bioanode, realizing the dual route energy conversion of light energy and chemical energy to electricity. The hierarchical branched TiO2 nanorods (B-TiO2 NRs) decorated with CdS quantum dots (QDs) act as the substrate to confine glucose dehydrogenase (GDH) for the visible light driven glucose oxidation at the bioanode. Three dimensional flowers like hierarchical carbon/gold nanoparticles/bilirubin oxidase (3D FCM/AuNPs/BOD) bioconjugate served as biocatalyst for O2 reduction at the biocathode. With an increase in the concentration of PSA, the amount of BOD labels on biocathode increases, thus leading to the higher current output of the as-proposed visible light driven BFC. Based on this, this sensing platform provide great performance in sensitivity and specificity, increasing linear detection range from 0.3pgmL(-1) to 7μgmL(-1) with a detection limit of 0.1pgmL(-1). Most importantly, our new sensing strategy provided a simple and inexpensive sensing platform for tumor markers detection, suggesting its wide potential applications for clinical diagnostics.

In this work, a “signal-off” photoelectrochemical DNA sensing strategy was proposed on the basis of the DNA hybridization induced conformational conversion using CdS quantum dots (QDs) sensitized titanium oxide (TiO2) nanorod array as photoactive material. Highly oriented, single-crystalline TiO2 nanorod arrays were grown directly on fluorine doped tin oxide (FTO) substrate by the hydrothermal method and employed as matrix for immobilization of capturing hairpin DNA probe, whereas CdS QDs as visible light antennae were successively labeled on the terminal of capturing hairpin DNA probe. Compared with pure TiO2 nanorods array, CdS QDs sensitized TiO2 nanorods array evidently extended the absorption edge and exhibited enhanced photoelectrochemical response in the visible region. In the absence of the target DNA, the direct attachment of CdS QDs to TiO2 nanorod array could reduce charge recombination and hence amplify photocurrent intensity. While in the presence of target DNA, the specific recognition of the target DNA with the capturing hairpin DNA–CdS probe would trigger the conformational conversion of capturing hairpin DNA–CdS probe leading to the quenching of photocurrent. Under optimized conditions, this “signal-off” photoelectrochemical sensing strategy shows a linear relationship between photocurrent variation and the logarithm of target DNA concentration in the range from 10 aM to 100 pM with a detection limit of 5.2 aM. Moreover, it exhibits good performance of excellent specificity, high stability, and acceptable fabrication reproducibility. This present strategy opens an alternative avenue for photoelectrochemical signal transduction and expands the applications of photoelectrochemical biosensing and clinical diagnosis.

Photoelectrochemical (PEC) cell, representing as one of the most promising candidates to implement solar-driven unassisted overall water splitting, still remains a bottleneck in the construction of technology strategies for efficient solar energy utilization due to the intermittent nature of sunlight. Herein, we demonstrate an approach to realize round-the-clock hydrogen production by a solar rechargeable tandem PEC cell with two photoactive electrodes, where the photoanode is composed of a pseudocapacitive WO3 nanoflakes film sensitized with visible-light responsive zeolitic-imidazolate-framework-67 (ZIF-67), and the photocathode is constituted with a Z-scheme BiVO4-black phosphorus (BP) heterojunctions that can broaden the light absorption to near-infrared (NIR) region as well as maintain the strong redox ability to fasten hydrogen evolution reactions by the effective charge separation. Deliberately, the alignment of Fermi level between the as-prepared WO3-ZIF-67 photoanode and BiVO4-BP photocathode permits us to realize a tandem PEC cell with reversible electron storage property, enabling light-induced charge storing and on-demand release in the dark, for the application of unassisted overall water splitting. The formed tandem PEC cell shows a promising strategy for the conversion of solar power into hydrogen fuel by integrating pseudocapacitive materials into man-made photovoltaic cells, and provides a new guidance for the design of multi-functional PEC device.

A chemiluminescent (CL) excited photoelectrochemical (PEC) immunosensor for detection of carcinoembryonic antigen (CEA) was introduced into microfluidic paper-based analytical devices (μ-PADs) integrated with a paper supercapacitor (PS) amplifier, and a terminal digital multi-meter (DMM) detector, based on CdS/TiO 2 hybrid modified porous Au-paper electrode. The effective matching of energy levels between the conduction bands of CdS and TiO 2 allowed for fast electron injection from excited CdS to TiO 2 upon irradiation, which inhibited the recombination process of electron–hole pairs and prompted PEC performance. Using CEA/ABEI-AuNPs-GOx bioconjugates as signal labels which featured CEA, N-(aminobutyl)-N-(ethylisoluminol) (ABEI) and glucose oxidase (GOx) linked to Au nanoparticles for signal amplification could greatly enhance the sensitivity. GOx could catalyze glucose to produce H 2 O 2 , which acted as a co-reactant in the ABEI-AuNPs-H 2 O 2 - p -iodophenol (PIP) CL system as well as sacrificial electron donor to scavenge the photogenerated holes in the valence band of CdS QDs, further causing an enhanced photocurrent. The quantification mechanism of this strategy is based on the charging of this PS by the photocurrent. The generated photocurrent could be stored by the PS and released instantaneously through a low cost, portable, and simple DMM to obtain an amplified current for the quantification of CEA. Under the optimal conditions, this analytical platform could detect CEA at concentrations at picomole level. This work offers a new route to highly selective and sensitive detection of biologically important small molecules.

In this work, we developed a novel electrochemiluminescence (ECL) platform for ultrasensitive and selective detection of MCF-7 cancer cells. To construct the platform, three-dimensional macroporous AuNPs@graphene complex was prepared through freeze drying process to modify glassy carbon electrode, which provided an effective matrix for concanavalin A to capture cancer cells due to its high surface area-to-weight ratio and excellent mechanical properties. The carbon quantum dots (CQDs) coated mesoporous silica nanoparticles were used as excellent ECL tracers due to their low cytotoxicity and good biocompatibility. Then, the prepared tracers were conjugated with mucin1 aptamer to specifically bind mucin1 on cancer cells with high stability and bioactivity. Structure characterization was obtained by means of transmission electron microscopy and scanning electron microscopy images. The proposed method showed a good analytical performance for the detection of MCF-7 cancer cells ranging from 500 to 2 × 107 cells·mL−1 with a detection limit of 230 cells mL−1. The as-proposed device has the advantages of high sensitivity, nice specificity, and good stability and could offer great promise for sensitive detection of MCF-7 cancer cells in response to therapy.

An ultrasensitive photoelectrochemical (PEC) immunoassay of cancer biomarker carcinoembryonie antigen (CEA) is proposed that uses rhombic titanium dioxide nanocrystals (TiO2 NCs) coupled with Ab2-RGO-Ru bioconjugate, which featured CEA signal antibody (Ab2) and ruthenium tris(bipyridine) (Ru complex) labels linked to reduced graphene oxide (RGO) for signal amplification. Herein, the Ru complex acts as an electron donor, while RGO serves as an electron acceptor which facilitates charge separation and suppresses recombination of photoexcited electron-hole pairs in the hybridized species. The rhombic TiO2 NCs were fabricated through a solvothermal technique in anhydrous ethanol, followed by spin-coating process and calcination, an ITO/TiO2 electrode was obtained. Chitosan (CS) and glutaraldehyde (GLD) were used to modify the prepared ITO/TiO2 electrode to covalently immobilize antibodies. With a sandwich-type immunoreaction, CEA and Ab2-RGO-Ru were conjugated successively to form a sandwich-type immunocomplex. Thus, a sandwich-type PEC immunosensor was fabricated for the detection of CEA was developed by monitoring the changes in the photocurrent signals of the electrode resulting from the immunoreaction. The proposed PEC immunosensor showed high sensitivity, selectivity, excellent stability, and good reproducibility, and thus has great potential to be used for other biological assays.

Driven by the urgent demand of high-selectively point-of-care testing device for pesticide, molecular imprinting-photoelectrochemistry (MI-PEC) was introduced into microfluidic paper-based analytical strategy to design a novel paper-based photoelectrochemical (paper-based PEC) protocol. The MI-PEC strategy was constructed based on CdTe quantum dots dotted molecular imprinted polymers (CdTe QDs@MIPs), and triggered by a common ultraviolet lamp (∼365 nm, 50$). The paper-based PEC sensor was fabricated by immobilizing CdTe QDs@MIPs on paper-based screen-printed working electrodes (WEs) via gold nanoparticles (Au NPs), which was electrodeposited on the surface of WE to improve the electron transfer efficiency for high sensitivity. Using S-fenvalerate as model analyte, the produced photocurrent from the proposed paper-based MI-PEC sensor upon ultraviolet radiation decreased with the increasing concentrations of S-fenvalerate solution, and the quenched paper-based MI-PEC showed a low detection limit of 3.2 × 10 −9 mol L −1 . This study has made a successful attempt in the development of highly selective and sensitive photoelectrochemical sensor for S-fenvalerate monitoring.