Ultrathin mesoporous BiOCl nanosheets-mediated liposomes for photoelectrochemical immunoassay with in-situ signal amplification

Recent advances in microfluidic-based photoelectrochemical (PEC) sensing platforms for biomedical applications

Photoelectrochemical (PEC) techniques seamlessly combine electrochemical and spectroscopic principles, offering a powerful platform for the detection of biomarkers and biological molecules in clinical and biomedical settings. This review provides a comprehensive overview of microfluidic PEC probes, emphasizing their potential for ultrasensitive detection through enhanced light absorption and charge transfer processes. Key advantages of microfluidic PEC include real-time monitoring of biological processes, non-invasive detection, and the possibility of multiplexing when integrated with various quantification modalities. However, the practical implementation of PEC faces challenges such as bulky setup, matrix interference, and stability of PEC-active materials. Also, this paper discusses the intricate mechanisms of PEC sensing, highlighting the roles of nanomaterials in enhancing microfluidic PEC systems. Additionally, the limitations inherent in PEC material selection, including stability and bandgap engineering, are critically discussed. Solutions such as doping and the development of composite materials are proposed to address these issues. Through presented examples of PEC applications in biomedical fields, this review elucidates the future potential of PEC-based methods as reliable and effective tools for diagnostic applications. Additionally, this review proposes the most effective probes for future investigations to develop commercial devices.

Development and characterization of caffeine-loaded nanoliposomes decorated by cationic amylose and cationic amylose- menthol inclusion complex coatings; a novel oral co-delivery system

Nanoliposomes (NLPs) have evolved as compelling carriers for loading bioactive compounds. To improve the phospholipid bilayer membrane stability, caffeine-loaded NLPs were coated with cationic amylose (CA) and CA-menthol inclusion complexes (CAMICs). The zeta potential results indicated an electrostatic attraction between CA and the negatively charged NLPs. Observations from dynamic light scattering, atomic force microscopy, and Fourier transform infrared spectroscopy demonstrated the efficient deposition of both CA and CAMICs onto the surface of NLPs without altering their spherical shape. Raman spectra and X-ray diffraction patterns indicated that both CA and CAMICs can decrease membrane fluidity and enhance lipid packing laterally. Additional assessment through thermogravimetric analysis revealed that the coating of NLPs, particularly with CAMICs, protected caffeine against thermal degradation. These coated NLPs show promise for formulation advancement, facilitating the simultaneous delivery of functional compounds.

Photoelectrochemical sensor for nitrite determination based on the etching of BiOCl/Zn0.5Cd0.5S

A rapid photoelectrochemical (PEC) sensor was constructed for nitrite detection in food based on the one-step chemical etching strategy of BiOCl/Zn0.5Cd0.5S (BOC/ZCS) nanocomposites by nitrite. BOC/ZCS heterojunction was prepared by a simple coprecipitation method, and it was found that BOC/ZCS showed significant photoelectrochemical (PEC) activity. The results of this study confirmed that the decrease in the photocurrent of the sensor was linked to the etching of ZCS by nitrite under acidic conditions. Under optimized conditions, the BOC/ZCS-based PEC sensor showed good analytical properties for detecting nitrite, with linear ranges of 1-100 μM and 100-600 μM. The detection limit of the sensor was 0.41 μM (S/N = 3). Excellent repeatability, reproducibility, low background noise, and immunity to interference were demonstrated using the proposed system, and satisfactory results were achieved for the nitrite assay using real samples. These results demonstrate a new method for nitrite detection developed using the proposed PEC sensor.

A liposome-based assay for cancer biomarker detection: exploring the correlation between platelet-derived microvesicles and NSCLC-associated miRNAs

Advances in molecular biology have enabled the identification of numerous cancer biomarkers, offering the potential to improve the diagnosis and prognosis of cancer. In non-small cell lung cancer (NSCLC), the role of platelet-derived microvesicles (PMVs) in cancer progression has received limited attention. While previous studies have focused on the increase of extracellular vesicles in plasma and their interaction with cancer, the expression of microRNAs (miRNAs) delivered through PMVs following platelet activation has remained largely unexplored. This study fills this knowledge gap by investigating miRNA expression in PMVs isolated from healthy donors and NSCLC patients following calcium treatment, a known platelet activator. A significant correlation was found between PMV levels and the expression of specific miRNAs; specifically, miRNA-21 expression increased 7.89 ± 0.44-fold in NSCLC patients and 7.12 ± 0.49-fold in healthy donors after calcium treatment. These findings highlight the potential of PMVs and their miRNA cargo to serve as specific biomarkers for NSCLC, offering valuable insights into cancer diagnosis and prognosis. To facilitate the sensitive detection of these miRNAs, a novel carboxyfluorescein (CF)-loaded liposome-based assay was developed. This assay demonstrated enhanced sensitivity, achieving a detection limit of 1.03 pg mL-1, when combined with a calcium platelet-activation approach. This research has the potential to lead to the development of innovative diagnostic tools and therapeutic strategies, ultimately improving outcomes for patients with NSCLC and other cancers.

Magnetoresponsive liposomes applications in nanomedicine: A comprehensive review

Safe and effective cancer therapy requires a suitable nanocarrier that can target particular sites, such as cancer cells, in a selective manner. With the tremendous growth in nanotechnology, liposomes, among various competing nanocarriers, have shown promising advances in cancer therapy. Magnetic nanoparticles and metal ions are wide-reaching candidates for conferring magnetic properties and for incorporation into liposomes. Combining liposomes with magnetic structures enables construction of magnetoresponsive liposomes, allowing stimuli-responsiveness to an alternating magnetic field, magnetic targeting, and tracking by magnetic resonance imaging, which could all occur in parallel. This review presents a comprehensive analysis of the practical advances and novel aspects of design, synthesis and engineering magnetoresponsive liposomes, emphasizing their diverse properties for various applications. Our work explores the innovative uses of these structures, extending beyond drug delivery to include smart contrast agents, cell labeling, biosensing, separation, and filtering. By comparing new findings with earlier studies, we showcase significant improvements in efficiency and uncover new potentials, setting a new benchmark for future research in the field of magnetoresponsive liposomes.

Signal amplification strategies in photoelectrochemical sensing of carcinoembryonic antigen

Early detection of cancer markers is critical for cancer diagnosis and cancer therapy since these markers may indicate cancer risk, incidence, and disease prognosis. Carcinoembryonic antigen (CEA) is a type of non-specific and broad-spectrum cancer biomarker commonly utilized for early cancer diagnosis. Moreover, it serves as an essential tool to assess the efficacy of cancer treatment and monitor tumor recurrence as well as metastasis, thus garnering significant attention for precise and sensitive CEA detection. In recent years, photoelectrochemical (PEC) techniques have emerged as prominent methods in CEA detection due to the advantages of PEC, such as simple equipment requirements, cost-effectiveness, high sensitivity, low interference from background signals, and easy of instrument miniaturization. Different signal amplification methods have been reported in PEC sensors for CEA analysis. Based on these, this article reviews PEC sensors based on various signal amplification strategies for detection of CEA during the last five years. The advantages and drawbacks of these sensors were discussed, as well as future challenges.

Emerging electrochemical biosensors for lung cancer-associated protein biomarker and miRNA detection

Lung cancer remains a major driver of global morbidity and mortality, and diagnosing lung tumors early in their development is vital to maximizing treatment efficacy and patient survival. Several biomarkers, including CYFRA 21-1, NSE, ProGRP, CEA, and miRNA, have been identified as reliable indicators for early lung cancer detection and monitoring treatment progress. However, the minute changes in the levels of these biomarkers during the early stages of disease necessitate advanced detection platforms. In this space, electrochemical biosensors have currently emerged as robust tools for early lung cancer screening and diagnosis owing to their low costs, rapid responses, and superior sensitivity and selectivity. This review provides an up-to-date overview of the application of electrochemiluminescence, photoelectrochemical, and other electrochemical analytical strategies for detecting lung cancer-associated protein biomarkers, and miRNA. This review compares these techniques to provide a concise overview of the principles underlying these electrochemical analytical methods, the preparation of their components, and the performance of the resulting biosensors. Lastly, a discussion of the challenges and opportunities associated with electrochemical biosensors detection of lung cancer-associated biomarkers are provided.

Near-infrared light-enhanced colorimetric signal amplification strategy for tumor marker detection based on MoS2/CuO/Au nanocomposite

A novel signal amplification strategy was developed by combining near-infrared light with MoS2/CuO/Au nanocomposite for building a colorimetric immunoassay. First, MoS2/CuO/Au nanocomposite was synthesized by precipitation and photoreduction methods and characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). MoS2/CuO/Au nanocomposite has oxidase-like activity and can oxidize TMB to form a blue product (TMBox). Further, the catalytic oxidation of TMB was accelerated under near-infrared (NIR) laser radiation. The sandwich-type colorimetric immunoassay was constructed using MoS2/CuO/Au nanocomposite. Under the enhancement of near-infrared light, carcinoembryonic antigen (CEA) was sensitively detected in the range 0.1 to 40 ng/mL with the limit of detection of 0.03 ng/mL. Moreover, the immunosensor has excellent selectivity and anti-interference, good repeatability, and stability.

An ultrasensitive electrochemical immunosensor based on meso-PdN NCs and Au NPs/N-CNTs for quantitative cTnI detection

Electrochemical immunosensors have gained considerable attention in detecting human disease markers due to their excellent specificity, high sensitivity, and facile operation. Herein, a rational-designed sandwich-type electrochemical immunosensor is constructed for the sensitive detection of cardiac troponin I (cTnI) using nitrogen-doped carbon nanotubes loaded with gold nanoparticles (Au NPs/N-CNTs) as substrate and highly active mesoporous palladium-nitrogen nanocubes (meso-PdN NCs) as secondary antibody markers. Benefitting from its large specific surface area (638.04 m2 g-1) and high nitrogen content, novel polydopamine (PDA)/ halloysite nanotubes (HNTs) hybrid derived one-dimensional (1D) N-CNTs can provide more binding sites for the in-situ growth of Au NPs to connect Ab1. Furthermore, as an ideal substrate material, Au NPs/N-CNTs exhibit finely tuned mesoporous structures and outstanding conductivity, which facilitate the mass and electron transfer during the electrocatalysis process. Besides, highly concave surfaces and crystalline mesopores of meso-PdN NCs expose more surfaces and crevices, providing abundant reactive sites for H2O2 reduction. Remarkably, the as-obtained immunosensor presented a wide linear range (from 10 fg mL-1 to 100 ng mL-1) and an excellent low detection limit (9.85 fg mL-1). This study may offer new insights into the precise fabrication of efficient electrochemical immunosensors for various clinical diagnosis applications.

Surface plasmon resonance-enhanced photoelectrochemical immunoassay with Cu-doped porous Bi2WO6 nanosheets

The development of rapid screening sensing platforms to improve pre-screening mechanisms in community healthcare is necessary to meet the significant need for portable testing in biomarker diagnostics. Here, we designed a portable smartphone-based photoelectrochemical (PEC) immunoassay for carcinoembryonic antigen (CEA) detection using Cu-doped ultrathin porous Bi2WO6 (CuBWO) nanosheets as the photoactive material. The CuBWO nanosheets exhibit a fast photocurrent response and excellent electrical transmission rate under UV light due to their surface plasmon resonance effect (SPR). The method uses glucose oxidase-labeled secondary antibody as a signal indicator for sandwich-type immune conjugation. In the presence of the target CEA, the electrons and holes generated at the surface of the photo-excited ultrathin porous CuBWO were rapidly consumed by the production of H2O2 from glucose oxidase oxidizing glucose, resulting in a weakened photocurrent signal. The photocurrent intensity increased logarithmically and linearly with increasing CEA concentration (0.02-50 ng mL-1), with a detection limit of 15.0 pg mL-1 (S/N = 3). The system provides a broader idea for inferring the electron-hole transport mechanism in ultrathin porous nanosheet layer materials and developing efficient PEC sensors.

A signal "switch-on" photoelectrochemical sensor based on a 3D-FM/BiOI heterostructure for the sensitive detection of l-ascorbic acid

A highly efficient 3D flower MoS2 (3D-FM)-based heterostructure photocatalyst (3D-FM/BiOI) was successfully obtained via a simple hydrothermal synthesis strategy. 3D-FM/BiOI showed prominent photoelectrochemical performance, distinguished stability and good selectivity. The introduction of 3D-FM, by promoting the photoelectric property attributed to it, facilitated the separation of photogenerated electron-hole pairs. Since the redox process of l-ascorbic acid (l-AA) resulted in an increasing photocurrent of 3D-FM/BiOI, a signal "switch-on" photoelectrochemical sensor (PECS) was designed to sensitively determine l-AA for the first time. Under optimized conditions, the 3D-FM/BiOI PECS worked over a wide range from 1 μM to 0.8 mM with a low detection limit of 0.05 μM (S/N = 3). The PECS was successfully exploited for l-AA sensing in human urine with excellent accuracy and applicability, demonstrating its practical precision and superb serviceability. Furthermore, the 3D-FM/BiOI PECS exhibited satisfactory selectivity and stability, providing a great potential platform for the construction of an l-AA sensor in various practical samples and complicated environments.

Recent Progress in Photoelectrochemical Sensing of Pesticides in Food and Environmental Samples: Photoactive Materials and Signaling Mechanisms

Pesticides have become an integral part of modern agricultural practices, but their widespread use poses a significant threat to human health. As such, there is a pressing need to develop effective methods for detecting pesticides in food and environmental samples. Traditional chromatography methods and common rapid detection methods cannot satisfy accuracy, portability, long storage time, and solution stability at the same time. In recent years, photoelectrochemical (PEC) sensing technology has gained attention as a promising approach for detecting various pesticides due to its salient advantages, including high sensitivity, low cost, simple operation, fast response, and easy miniaturization, thus becoming a competitive candidate for real-time and on-site monitoring of pesticide levels. This review provides an overview of the recent advancements in PEC methods for pesticide detection and their applications in ensuring food and environmental safety, with a focus on the categories of photoactive materials, from single semiconductor to semiconductor-semiconductor heterojunction, and signaling mechanisms of PEC sensing platforms, including oxidation of pesticides, steric hindrance, generation/decrease in sacrificial agents, and introduction/release of photoactive materials. Additionally, this review will offer insights into future prospects and confrontations, thereby contributing novel perspectives to this evolving domain.