How Intimate Partner Violence Is Influenced by Social Identity Among Sexual Minority Men.

Purpose: Sexual minority men (SMM) experience intimate partner violence (IPV) at disproportionately high rates. The objective of this article was to identify the experiences of SMM and health care providers on how social identity impacts IPV. Methods: SMM participants (N = 23) were recruited from online community settings and a lesbian, gay, bisexual, transgender, queer, and others (LGBTQ+) organization in Los Angeles; providers (N = 10) were recruited from LGBTQ+ organizations. Semistructured interviews were audio recorded and transcribed verbatim. An applied thematic analysis approach was implemented to create memos, inductively generate a codebook, apply codes to the transcripts, and identify key themes in data. Results: Three main themes were identified. The first theme was weaponizing social identity to control a partner, which had three subthemes: (1) immigration status, race/ethnicity, and skin color, (2) threatening to "out" the partner's sexual orientation, and (3) abusing power inequity. Men who perpetrated IPV often used minority identities or undisclosed sexuality to leverage power over their partner. The second theme was use of IPV to establish masculinity, by exerting power over the more "feminine" partner. The third theme was internalized homophobia as a root cause of IPV, which details how internalized homophobia was often expressed in violent outbursts toward partners. Conclusion: These findings highlight how IPV among SMM can be influenced by social and sexual identity. Future research must consider socially constructed power structures and the multiple identities of SMM when developing interventions to address IPV in this population.

Substance Use and Misuse among Sexual and Gender Minority Communities Living in Former Soviet Union Countries: A Scoping Review.

Objectives: We reviewed literature examining substance use among sexual and gender minorities (SGM) living in the former Soviet Union (USSR) nations. Methods: Searches were conducted across five databases (PubMed, SocINDEX, CINAHL, PscyInfo, LGBTQ + Source) to identify peer-reviewed literature. Results: Across 19 studies, high hazardous substance use prevalence was documented. Substance use was correlated with (a) sexual health and behaviors and (b) mental wellbeing and the use of other substances. Conclusion: We discuss minority stress implications and challenges presented by the paucity of evidence in the literature examining substance use among SGM women and SGM living in countries unrepresented in reviewed studies.

Two Birds with one Stone: Dual-mode immunoassay constructed using a novel emitter ethylene glycol-induced perylene diimide and a multifunctional ANS probe.

Perylene diimide (PDI) is a readily reducible electron-deficient dye that exhibits strong photoluminescent properties, providing new opportunities for synthesizing novel electrochemiluminescence (ECL) emitters. In this study, ethylene glycol (EG) was used to induce the self-assembly of PDI supramolecules for the preparation of ultrathin EG-PDI nanosheets characterized by low crystallinity and weak stacking interaction. Notably, EG-PDI integrates luminescent and catalytic functions into one device, accelerating the interfacial electron transfer and the faster charge transfer kinetics of EG-PDI with K2S2O8. Furthermore, the narrow band gap of EG-PDI facilitates its excitation at an ultra-low potential (-0.3 V). To improve the efficiency of tumor marker analysis, multifunctional Au nanostars (ANS) was introduced both as an energy acceptor of the ECL system and a probe for the photothermal system. Dual-mode immunoassay have demonstrated superior analytical performance in detecting alpha-fetoprotein (AFP), meeting the requirements of modern clinical diagnostics in resource-limited environments.

Examining Factors Associated with Cannabis Use Among Sexual and Gender Minority and Cisgender Heterosexual Emerging Adults in California.

Purpose: We explored correlates of cannabis risk and examined differences between sexual and gender minority (SGM) and cisgender heterosexual emerging adults (ages 18-29) in California. Methods: We recruited 1491 participants aged 18-29 years for a cross-sectional online survey. Ordinal logistic regressions assessed associations between minority stress (discrimination and internalized homophobia [IH]), social support (perceived social support and lesbian, gay, bisexual, transgender, and queer+ [LGBTQ+] community connectedness), and cannabis risk scores (low, medium, and high risk of developing problems related to their cannabis use). We also explored differences in cannabis risk scores by sexual orientation and gender identity (SOGI). Results: Higher everyday discrimination scores were associated with increased odds of self-scoring in a higher cannabis risk range (adjusted odds ratio = 1.53, 95% confidence interval [CI] = 1.31-1.79). We found no significant associations for IH, LGBTQ+ community connectedness, or social support on cannabis risk scores. There were also no statistically significant differences by SOGI groups; however, SOGI did moderate the relationship between IH and cannabis risk score such that the slope for IH was 0.43 units higher for cisgender sexual minority women compared to cisgender sexual minority men (95% CI = 0.05-0.81). Conclusion: Our findings suggest that experiences of everyday discrimination are important contributors to developing cannabis-related problems and IH may have more pronounced effects for sexual minority women compared to sexual minority men. More research is needed to better understand risk and protective factors of cannabis risk to inform the development of culturally tailored interventions for SGM emerging adults.

Co3O4/NiCo2O4 heterojunction as oxygen evolution reaction catalyst for efficient luminol anode electrochemiluminescence.

Luminol has garnered significant attention from analysts as one of the most effective and commonly used electrochemiluminescence (ECL) reagents. However, the efficient luminescence of luminol anode is limited by the excitation of various reactive oxygen species (ROS). Typically, ROS are generated through co-reactive reagents and dissolved oxygen. Unfortunately, the former suffers from two drawbacks, namely biotoxicity and instability, while the latter cannot offer sufficient oxygen due to its limited solubility in aqueous solutions. Consequently, a low decomposition rate is usually obtained, leading to insufficient ROS. Therefore, there is an urgent need to develop efficient luminol anode systems. This study focuses on the use of zeolitic imidazolate framework-67 (ZIF-67) as a template, employing a controlled chemical etching method to create a ZIF-67/Ni-Co-layered double hydroxide (LDH). The intermediate composite is then annealed in air, resulting in the formation of a Co3O4/NiCo2O4 double-shelled nanobox (DSNB) heterostructure. Due to its structural advantages, the DSNB exhibits excellent electrocatalytic performance in the oxygen evolution reaction (OER). Furthermore, it was found that both the intermediates and products of OER can directly participate in the luminol chemiluminescence process, ultimately resulting in a 700-fold increase in the electrochemiluminescence (ECL) signal compared to an equal molar concentration of luminol solution. This work not only establishes the OER-mediated ECL system but also deepens the understanding of the relationship between ROS and luminol, providing a new pathway to study the luminol anodic ECL luminescence system.

Electrochemiluminescence Enhancement and Passivation Mitigation in Carbon Nitride Semiconductors via an Integrated Ternary Heterostructure Strategy.

In recent years, carbon nitride (CN) has attracted substantial attention in the field of electrochemiluminescence (ECL) applications, owing to its outstanding optical and electronic properties. However, the passivation of CN during the ECL process has contributed to reduced stability and poor repeatability. While some studies have tried to boost ECL performance by altering CN through doping and vacancies, effectively suppressing CN passivation at high potentials continues to be challenge. In this study, the built-in electric field and the Schottky barrier effect is used to expedite the transfer of electrons from CN to the molybdenum disulfide (MoS2 ) conduction band. This transfer deterred excessive electron injection into the CN band, thus mitigating its electrochemical degradation. Moreover, by introducing nickel nanoparticles (Ni NPs) as catalytic active sites, it is facilitated that the decomposition of potassium persulfate (K2 S2 O8 ), thereby enhancing both the stability and intensity of ECL emission. In the end, the application of ternary heterostructure as sensing platform for the cancer biomarker carcinoembryonic antigen (CEA) demonstrated high sensitivity. This research introduces a novel approach to overcome CN passivation, paving the way for more promising applications of CN in energy, environmental, and biosensing fields.

A signal amplification electrochemiluminescence biosensor based on Ru(bpy)32+ and ß-cyclodextrin for detection of AFP.

By combining two different materials, metal-organic frameworks (MOF) and ß-cyclodextrins (ß-CD), a signal amplification electrochemical luminescence (ECL) immunosensor was constructed to realize the sensitive detection of AFP. The indium-based metal-organic framework (In-MOF) was used as the carrier of Ru(bpy)32+, and Ru(bpy)32+ was immobilized by In-MOF through suitable pore size and electrostatic interaction. At the same time, using host-guest recognition, ß-CD enriched TPA into the hydrophobic cavity for accelerating the electronic excitation of TPA, then, achieving the purpose of signal amplification. The signal amplification immunosensor structure is constructed among the primary antibody Ab1 connected to the Ru(bpy)32+@In-MOF modified electrode, AFP, BSA and the secondary antibody (Ab2) loaded with TPA-ß-CD. The immunosensor has a good linearity in the range of 10-5 ng/mL-50 ng/mL, and the low limit of detection (LOD) is 1.1 × 10-6 ng/mL. In addition, the electrochemiluminescence immunosensor that we designed has strong stability, good selectivity and repeatability, which provides a choice for the analysis of AFP.

NiCo-LDH Hollow Nanocage Oxygen Evolution Reaction Promotes Luminol Electrochemiluminescence.

Conventional luminol co-reactant electrochemiluminescence (ECL) systems suffer from low stability and accuracy due to factors such as the ease of decomposition of hydrogen peroxide and inefficient generation of reactive oxygen species (ROS) from dissolved oxygen. Inspired by the luminol ECL mechanism mediated by oxygen evolution reaction (OER), the nickel-cobalt layered double hydroxide (NiCo-LDH) hollow nanocages with hollow structure and defect state are used as co-reaction promoters to enhance the ECL emission from the luminol-H2 O system. Thanks to the hollow structure and defect state, NiCo-LDH hollow nanocages show excellent OER catalytic activity, which can stabilize and efficiently produce ROS and enhance the ECL emission. Additionally, mechanistic exploration suggests that the ROS involved in the co-reaction of the luminol-H2 O system are derived from the OER reaction process, and there is a positive correlation between ECL intensity and the OER catalytic activity of the co-reaction promoter. The selection of catalysts with excellent OER catalytic activity is a key factor in improving ECL emission. Finally, a dual-mode immunosensor is constructed for the detection and analysis of alpha-fetoprotein (AFP) based on the promoting effect of NiCo-LDH hollow nanocages on the luminol-H2 O ECL system.

Construction of a Dual-Mode Immune Platform Based on the Photothermal Effect of AgCo@NC NPs for the Detection of α-Fetoprotein.

Compared with the accuracy of a single signal and the limitation of environmental applicability, the application value of dual-mode detection is gradually increasing. To this end, based on the photothermal effect of Ag/Co embedded N-rich mesoporous carbon nanomaterials (AgCo@NC NPs), we designed a dual-mode signal response system for the detection of α-fetoprotein (AFP). First, AgCo@NC NPs act as a photothermal immunoprobe that converts light energy into heat driven by a near-infrared (NIR) laser and obtains temperature changes corresponding to the analyte concentration on a hand-held thermal imager. In addition, this temperature recognition system can significantly improve the efficiency of Fenton-like reactions. AgCo@NC NPs act as peroxidase mimics to initiate the generation of poly N-isopropylacrylamide (PNIPAM, resistance enhancer) by cascade catalysis and the degradation of methylene blue (MB), thus enabling electrochemical testing. The dual-mode assay ranges from 0.01 to 100 and 0.001-10 ng/mL, with lower limits of detection (LOD) of 3.2 and 0.089 pg/mL, respectively, and combines visualization, portability, and high efficiency, opening new avenues for future clinical diagnostics and inhibitor studies.

Mpox on Reddit: a Thematic Analysis of Online Posts on Mpox on a Social Media Platform among Key Populations.

The 2022-2023 mpox outbreak has disproportionately impacted gay, bisexual, and other men who have sex with men (GBMSM). The US CDC recommended individuals to explore safer sexual practices that minimize the potential risk of exposure and also strongly encouraged for eligible individuals to prioritize vaccination. This study aimed to analyze social media data related to mpox on Reddit since the mpox outbreak and identify themes associated with the impact on social behaviors and social processes among targeted population. Publicly available data were collected from the social media Reddit. We extracted the summarized mpox-related posts since the beginning of May 2022 from popular subreddits that were popular among GBMSM. We thematically analyzed the content to identify the overall themes related to the GBMSM's responses to the outbreak. There is an overall increase in the number of daily mpox-related posts, with three upticks in late May, late July, and early August 2022, which may correspond to the dates that the first mpox case was identified in the USA, the WHO declared a global public health emergency, and the US Department of Health and Human Services declared a public health emergency. Four themes were identified: (1) changes in sexual behaviors and social activities; (2) mpox vaccine attitude, uptake, and hesitancy; (3) perceived and experienced stigma and homophobia, and mental distress; and (4) online information-seeking and mutual aid and support. GBMSM changed their sexual behaviors and social activities to mitigate their exposure to the virus during this outbreak and actively sought and shared information about mpox vaccination in their respective settings, while some were hesitant due to concerns about side effects and potential effectiveness. Perceived and experienced stigma and discrimination on gay- and same sex-identify have impacted GBMSM's mental health. Interventions to promote the mpox vaccine must address the historical medical mistrust and vaccine hesitancy among GBMSM.

Dual-functional Nanomaterials Polyo-phenylenediamine and Ru-Au Complement Each Other to Construct an Electrochemical and Electrochemiluminescent Dual-Mode Aptamer Sensor for Sensitive Detection of Alternariol.

To sensitively monitor trace amounts of alternariol (AOH) in fruits, a dual-mode aptamer sensor utilizing the dual-function nanomaterial PoPD/Ru-Au was developed. This sensor provides both electrochemical (EC) and electrochemiluminescence (ECL) signals, which can greatly avoid the potential false positive of the traditional single signal, thus enhancing the accuracy and reliability of detection results. Polyo-phenylenediamine (PoPD), known for its favorable EC response, can also assist in enhancing the ECL behavior of Ru-Au. Furthermore, Ru-Au demonstrates excellent ECL performance and effectively activates K2S2O8 to amplify the EC response of PoPD. The complementary effect of the two can effectively amplify the final detection signal. Additionally, the PoPD/Ru-Au nanomaterial exhibits excellent electrical conductivity, further enhancing the EC and ECL response signals. The experimental results demonstrate that the EC detection range of AOH was 0.01-100 ng/mL, while the ECL detection range was 0.001-100 ng/mL, both exhibiting a satisfactory linear relationship. Therefore, the mutual verification of the detection results can be highly realized, and the purpose of avoiding wrong detection can be achieved.

Violence Victimization, Homelessness, and Severe Mental Illness Among People Who Use Opioids in Three U.S. Cities.

This study examined the associations between violence victimization, homelessness, and severe mental illness (SMI) among people who use opioids (PWUOs) in three U.S. cities. We analyzed data from a cross-sectional survey conducted from May 2019 to February 2020 across three study sites: Los Angeles, CA; Las Vegas, NV; and Atlanta, GA. We used multivariable regressions to examine how multiple victimizations and housing situation are associated with SMI. Based on K-6 scale, nearly half (44.2%) were screened positive for SMI. Meanwhile, 69.7% of the participants reported experiencing some kind of violence in their lifetime, and more than half (51.9%) reported experiencing recent violence (in the past 6 months). The most common form of lifetime violence was emotional (59.5%), followed by physical and intimate partner violence (IPV) (56.1 and 34.9%, respectively), and 34.9% of all participants reported experiencing multiple forms of victimization in the past 6 months. Participants who reported homelessness were more likely to report having experienced recent violence victimization (p < .001). In multivariable models, experiencing recent victimization was significantly associated with SMI (adjusted odds ratio (AOR) = 1.85, 95% confidence interval [CI] [1.46, 2.38]), as was homelessness (AOR = 1.57, 95% CI [1.15, 2.14]), after adjusting for study covariates. Among those with moderate and SMI (n = 927), only 22% were currently receiving mental health services, and those who reported having experienced any forms of violence in the past 6 months were more likely to utilize mental health services than those who had not experienced any recent violence victimization (25 vs. 17.9%, p < .05). To improve mental health and wellness among this high priority population, mental health facilities and syringe service programs may consider screening for experiences of violence and using trauma-informed mental health approaches. Harm reduction interventions must be responsive to the diverse individual and structural-level needs of PWUOs, especially those experiencing homelessness and housing insecurity. Holistic strategies and services are needed to meet the social and structural needs of this population.

Construction of electrochemical and electrochemiluminescent dual-mode aptamer sensors based on ferrocene dual-functional signal probes for the sensitive detection of Alternariol.

In this study, a novel dual-mode aptamer sensor was developed using Fca-DNA2 as the quenching electrochemiluminescence (ECL) and electrochemical (EC) signal response probe, and Ru-MOF/Cu@Au NPs were used as the ECL substrate platform to detect Alternariol (AOH) via a competitive reaction between AOH and Fca-DNA2. Compared with the conventional aptamer sensor with a single detection signal, this dual-mode aptamer sensor has the following advantages: (1) Electrodeposition-based rapid synthesis Ru-MOF on the electrode surface. (2) The Signal amplification substance Cu@Au NPs can synergistically catalyze Triethanolamine (TEOA) to amplify ECL behavior. (3) The aptamer sensor employs the dual-functional material Fca, which can detect both ECL and EC signals, increasing the result accuracy. Both ECL and EC methods have excellent detection performance for AOH in the detection range of 0.1 pg/mL to 100 ng/mL, with detection limits of 0.014 and 0.083 pg/mL, respectively, and are expected to be used for sensitive AOH detection in real samples.

S-CdIn2S4: A novel near-infrared emitter triggered by low potential for constructing a dual-mode immunosensing platform.

CdIn2S4 is an interesting ternary metal sulfide whose narrow band gap and tunable optical properties offer new opportunities for the development of novel ECL emitters. Here, we use a simple hydrothermal synthesis to obtain hollow spindle CdIn2S4 (S-CIS), which exhibits strong near-infrared electrochemiluminescence (ECL) emission with K2S2O8 as a coreactant at a low excitation potential (-1.3 V), which is encouraging. The lower excitation potential of S-CIS is probably due to the low band gap energy, which makes the excitation potential positively shift. This lower excitation potential reduces the side-reactions caused by high voltages, effectively avoiding irreversible damage to biomolecules, and protecting the biological activity of antigens and antibodides. In this work, new features of S-CIS in ECL studies are also presented, demonstrating that the ECL emission mechanism of S-CIS is generated by surface state transitions and that S-CIS exhibits excellent near-infrared (NIR) characteristics. Importantly, we introduced S-CIS into electrochemical impedance spectroscopy (EIS) and ECL to the construct a dual-mode sensing platform to achieve AFP detection. The two models with intrinsic reference calibration and high accuracy showed outstanding analytical performance in AFP detection. The detection limits were 0.862 pg mL-1 and 16.8 fg mL-1, respectively. This study demonstrates the key role and great application potential of S-CIS as a novel NIR emitter with easy preparation, low cost and great performance in the development of a simple, efficient and ultrasensitive dual-mode response sensing platform for early clinical use.

Preparation of oxidized acetylene black by high-temperature calcination for luminol efficient cathodic electrochemiluminescence.

The improvement of electrochemiluminescence (ECL) intensity in luminol, a classic electrochemiluminescent material, remains a controversial topic. In this study, synthesis of acetylene black oxide (ACETO) through simple air annealing was successful in introducing oxygen-containing groups and defects, which can act as active sites for the oxygen reduction reaction (ORR) and exhibit excellent catalytic activity. By introducing the two-electron (2e-) ORR into the cathode ECL system of luminol, integration of ACETO and luminol allows for in situ generation of dissolved oxygen into reactive oxygen species (ROS), thereby enhancing the ECL intensity of luminol. It is worth noting that iron-nitrogen-carbon (FeNC), as a secondary antibody (Ab2) label, can catalyze the decomposition of H2O2, the product of 2e- ORR, into ROS to achieve ECL amplification. Alpha-fetoprotein (AFP), an important tumor marker, was successfully detected with a detection limit of 0.01 pg/mL, indicating that this ECL signal amplification strategy has broad application prospects in biological analysis.

Analysis of Smartphone Text Data Related to mpox from a U.S. Sample of Gay, Bisexual, and Other Men Who Have Sex with Men During the 2022 Outbreak.

Purpose: We sought to understand technology-based communication regarding mpox (monkeypox) among gay, bisexual, and other men who have sex with men (GBMSM) during the global outbreak in 2022. Methods: Forty-four GBMSM (Mage = 25.3 years, 68.2% cisgender, 43.2% non-White) living in the United States participated. From May 2022 to August 2022, all text data related to mpox (174 instances) were downloaded from the smartphones of GBMSM. Text data and smartphone app usage were analyzed. Results: Content analysis revealed 10 text-based themes and 7 app categories. GBMSM primarily used search and browser, texting, and gay dating apps to share vaccine updates, seek mpox vaccination, find general mpox information, share mpox information with other GBMSM, and discuss links between mpox and gay culture. Data visualizations revealed that changes in communication themes and app usage were responsive to major milestones in the mpox outbreak. Conclusion: GBMSM used apps to facilitate a community-driven mpox response.

An electrochemiluminescence resonance energy transfer biosensor based on Luminol-LDH and CuS@Pt for detection of alpha-fetoprotein.

Alpha-fetoprotein (AFP) is the best diagnostic marker for hepatocellular carcinoma (HCC) and plays an important role in the general surveillance of the population. Therefore, the establishment of an ultra-sensitive AFP assay is essential for the early screening and clinical diagnosis of HCC. In this work, we designed a signal-off biosensor for ultra-sensitive detection of AFP based on an electrochemiluminescent resonance energy transfer (ECL-RET) strategy using luminol intercalated layered bimetallic hydroxide (Luminol-LDH) as an ECL donor and Pt nanoparticles-grown on copper sulfide nanospheres (CuS@Pt) as ECL acceptor. The (Au NPs/Luminol-LDH)n multilayer nanomembrane synthesized by our intercalation and layer-by-layer electrostatic assembly process not only effectively immobilizes luminol but also significantly enhances the ECL signal. The CuS@Pt composite has well visible light absorption ability and can burst the light emitted from luminol by ECL-RET. The biosensor showed good linearity in the range from 10-5 ng mL-1 to 100 ng mL-1 and a minimum detection limit of 2.6 fg mL-1. Therefore, the biosensor provides a novel and efficient strategy for the detection of AFP, which is important for the early screening and clinical diagnosis of HCC.

Electrochemiluminescence Immunosensors Based on ECL-RET Triggering between Mn SANE/PEI-Luminol and PtCu/h-MPF for Ultrasensitive Detection of CEA.

In this paper, a novel donor-acceptor pair was creatively proposed based on the principle of electrochemiluminescence resonance energy transfer (ECL-RET): luminol immobilized on polyethyleneimine (PEI)-functionalized manganese-based single-atom nanozymes (Mn SANE/PEI-luminol, donor) and a PtCu-grafted hollow metal polydopamine framework (PtCu/h-MPF, acceptor). A quenched ECL immunosensor was constructed for the ultrasensitive analysis of carcinoembryonic antigen (CEA). Mn SANE, as an efficient novel coreaction accelerator with the outstanding performance of significantly activating H2O2 to produce large amounts of ROS, was further modified by the coreactant PEI, which efficiently immobilized luminol to form a self-enhanced emitter. As a result, the electron transport distance was effectively shortened, the energy loss was reduced, and luminol achieved a high ECL efficiency. More importantly, PtCu-grafted h-MPF (PtCu/h-MPF) was proposed as a novel quencher. The UV-vis spectra of PtCu/h-MPF partially overlap with the ECL spectra of Mn SANE/PEI-luminol, which can effectively trigger the ECL-RET behavior between the donor and the acceptor. The multiple quenching effect on Mn SANE/PEI-luminol was achieved, which significantly improved the sensitivity of the immunosensor. The prepared immunosensor exhibited good linearity in the concentration range of 10-5 to 80 ng/mL. The results indicate that this work provides a new method for the early detection of CEA in clinical diagnosis.

Depression as a mediator between intimate partner violence (IPV) and CD4 cell count among men who have sex with men (MSM) living with HIV in China.

Intimate partner violence (IPV) is associated with adverse mental and physical outcomes among men who have sex with men (MSM) living with HIV. Few studies focus on psychological IPV, such as verbal threats. This study examined the associations between different forms of IPV and depression and CD4+ cell count, with depression as a mediator for the association between IPV and CD4+ cell count. Data for these analyses were derived from a larger cross-sectional study on HIV-HCV co-infection among MSM in Shanghai, China (N = 1623). We estimated the average causal mediation effects (ACME) and average direct effects (ADE) through three steps. About 16% of participants experienced IPV, with forced sex (7%), verbal threats (5%), and thrown objects (4%) being most common. Verbal threats showed the strongest link with depression and low CD4+ cell count. Depression fully mediated the relationship between verbal abuse and low CD4+ cell count, suggesting it as a potential pathway between psychological IPV and poorer HIV-related health outcomes. More research on psychological IPV is warranted to examine its health impacts. Mental health could be a potential focus of intervention to enhance HIV-related health outcomes among MSM with IPV experience.

Construction of a competitive electrochemical immunosensor based on sacrifice of Prussian blue and its ultrasensitive detection of alpha-fetoprotein.

Effective signal amplification is a prerequisite for ultrasensitive detection by electrochemical immunosensors. For quantitative and ultrasensitive detection of alpha-fetoprotein (AFP), we designed a competitive electrochemical immunosensor and transferred the immunoreactivity from the electrode surface to the cuvette. AFP antigen was captured using AFP primary antibody (Ab1) immobilized on magnetic nanobeads (MBs), and ZIF-8 nanomaterials attached to secondary antibody (Ab2) were used as probes. MBs helped retain the sandwich structure in the test tube through incubation and washing steps. Then, an appropriately fixed excess of sodium ethylenediaminetetraacetic acid (EDTA) solution was added to the cuvettes, resulting in etching of Zn ions from ZIF-8 and formation of Zn-EDTA complexes. After magnetic separation, a certain amount of supernatant is added dropwise to the Prussian blue (PB)-modified electrode (GCE), and Fe ions (from PB) complex with the remaining EDTA in the supernatant, thus reducing the signal response value of PB. The higher the AFP concentration, the lower the amount of free EDTA in the supernatant, the less the destruction of PB, and therefore the higher the current. Under optimal conditions, the immunosensor achieved ultra-sensitive detection of AFP in the range of 10-4 ng/mL-100 ng/mL with a limit of detection (LOD) as low as 0.032 pg/mL (S/N = 3). The excellent performance provides an important tool for the early screening and detection of AFP.