Nanosheet Au/Co3O4-based ultrasensitive nonenzymatic immunosensor for melanoma adhesion molecule antigen

An immune sandwich electrochemical biosensor based on triple-modified zirconium derivatives for detection of CD146 in serum

CD146, also known as melanoma cell adhesion molecule (MCAM), is overexpressed in various cancer patients, making it a valuable predictor for early diagnosis. In this work, an immune sandwich electrochemical biosensor is proposed for sensitive and non-invasive quantitative detection of CD146 in serum. Zirconium-based MOF (UIO-66) was modified by simultaneous copper atom doping, in situ growth carbon-based support and physical embedding of platinum nanoparticles (PtNPs). Triple-modified Cu-UIO-66@SWCNT/PtNPs nanocomposites with high stability and excellent electrochemical properties, serve as surface modification materials for glassy carbon electrodes. Anti-CD146 antibody (Ab1) was grafted onto the electrode surface via Pt-S bond. Meanwhile, the secondary antibody (Ab2) was conjugated with silver nanoparticles (AgNPs) to cooperate for CD146 capture and achieve secondary electrical signal amplification. Under optimal conditions, square wave voltammetry was employed to determine CD146 in the concentration range of 10-9-10-4 mg/mL and a limit of detection of 12 fg/mL was obtained. Finally, it was successfully applied to the analysis of CD146 in lung and liver cancer patients' serum samples.

Biosensors for melanoma skin cancer diagnostics

Skin cancer is a critical global public health concern, with melanoma being the deadliest variant, correlated to 80% of skin cancer-related deaths and a remarkable propensity to metastasize. Despite notable progress in skin cancer prevention and diagnosis, the limitations of existing methods accentuate the demand for precise diagnostic tools. Biosensors have emerged as valuable clinical tools, enabling rapid and reliable point-of-care (POC) testing of skin cancer. This review offers insights into skin cancer development, highlights essential cutaneous melanoma biomarkers, and assesses the current landscape of biosensing technologies for diagnosis. The comprehensive analysis in this review underscores the transformative potential of biosensors in revolutionizing melanoma skin cancer diagnosis, emphasizing their critical role in advancing patient outcomes and healthcare efficiency. The increasing availability of these approaches supports direct diagnosis and aims to reduce the reliance on biopsies, enhancing POC diagnosis. Recent advancements in biosensors for skin cancer diagnosis hold great promise, with their integration into healthcare expected to enhance early detection accuracy and reliability, thereby mitigating socioeconomic disparities.

A Direct-Contact Photocurrent-Direction-Switching Biosensing Platform Based on In Situ Formation of CN QDs/TiO2 Nanodiscs and Double-Supported 3D DNA Walking Amplification

Herein, a direct-contact photocurrent-direction-switching photoelectrochemical (PEC) biosensing platform for the ultrasensitive and selective detection of soluble CD146 (sCD146) is reported for the first time via in situ formation of carbon nitride quantum dots (CN QDs)/titanium dioxide (TiO2 ) nanodiscs with the double-supported 3D DNA walking amplification. In this platform, metal organic frameworks (MOFs)-derived porous TiO2 nanodiscs exhibit excellent anodic photocurrent, whereas a single-stranded auxiliary DNA (ssDNA) as biogate is absorbed onto the TiO2 nanodiscs to block active sites. Subsequently, with the help of intermediate DNAs from target sCD146-induced double-supported 3D DNA walking signal amplification, the ssDNA can leave away from the surface of TiO2 nanodiscs due to the specific hybridization with intermediate DNAs. Afterward, the successful direct contact of CN QDs on TiO2 nanodiscs by porosity and electrostatic adsorption, leads to the effective photocurrent-direction switching from anodic to cathodic photocurrent. Based on direct-contact photocurrent-direction-switching CN QDs/TiO2 nanodiscs system and double-supported 3D DNA walking signal amplification, sCD146 is detected sensitively with a wide linear range (10 fg mL-1 to 5 ng mL-1 ) and a low limit of detection (2.1 fg mL-1 ). Also, the environmentally friendly and direct-contact photocurrent-direction-switching PEC biosensor has an application prospect for cancer biomarker detection.

Dual-mode biosensor platform based on synergistic effects of dual-functional hybrid nanomaterials

Detection of biomarkers is very vital in the prevention, diagnosis and treatment of diseases. However, due to the poor accuracy and sensitivity of the constructed biosensors, we are now facing great challenges. In addressing these problems, nanohybrid-based dual mode biosensors including optical-optical, optical-electrochemical and electrochemical-electrochemical have been developed to detect various biomarkers. Integrating the merits of nanomaterials with abundant active sites, synergy and excellent physicochemical properties, many bi-functional nanohybrids have been reasonable designed and controllable preparation, which applied to the construction dual mode biosensors. Despite the significant progress, further efforts are still needed to develop dual mode biosensors and ensure their practical application by using portable digital devices. Therefore, the present review summarizes an in-depth evaluation of the bi-functional nanohybrids assisted dual mode biosensing platform of biomarkers. We are hoping this review could inspire further concepts in developing novel dual mode biosensors for possible detection application.

Biomimetic Nanoscale Materials for Skin Cancer Therapy and Detection

Skin cancer has developed as one of the most common types of cancer in the world, with a significant impact on public health impact and the economy. Nanotechnology methods for cancer treatment are appealing since they allow for the effective transport of medicines and other biologically active substances to specific tissues while minimizing harmful consequences. It is one of the most significant fields of research for treating skin cancer. Various nanomaterials have been employed in skin cancer therapy. The current review will summarize numerous methods of treating and diagnosing skin cancer in the earliest stages. There are numerous skin cancer indicators available for the prompt diagnosis of this type of disease. Traditional approaches to skin cancer diagnosis are explored, as are their shortcomings. Electrochemical and optical biosensors for skin cancer diagnosis and management were also discussed. Finally, various difficulties concerning the cost and ease of use of innovative methods should be addressed and overcome.

Dual-responsive electrochemical immunosensor for detection of insulin based on dual-functional zinc silicate spheres-palladium nanoparticles

In this study, described an electrochemical immunoassay for insulin that is based on the use of zinc silicate spheres loaded with palladium nanoparticles (Zn₂SiO₄-PdNPs) that act as dual-function labels. The Zn₂SiO₄-PdNPs display high electrocatalytic activity towards the reduction of H₂O₂ and high sensitivity in chronoamperometry. The Zn₂SiO₄-PdNPs decrease the electron transfer rate between the electrolyte and the surface of the electrode, which can increase the changed current and enhance the sensitivity of the immunosensor as detected by square wave voltammetry (SWV). Electrodeposited gold is used as the matrix material. The icosahedral gold nanocrystals are coated with the primary antibodies formed a 3D mode to against abundant of insulin. Under optimal conditions, the assay has a linear response in the 0.1pgmL^-1 to 50ngmL^-1 insulin concentration range, and the limit of detection of the SWV and CA methods are 0.25 fg mL^-1 and 80 fg mL^-1, respectively. Moreover, the immunosensor holds an outstanding analytical performance for the insulin detection and has promising potential in clinical diagnosis.

Sulfur-Doped Graphene-Based Immunological Biosensing Platform for Multianalysis of Cancer Biomarkers

The accurate tumor marker detection at an early stage can prevent people from getting cancer to a great extent. Herein, a novel tri-antibody dual-channel biosensing strategy is applied in multianalysis of carcino-embryonic antigen (CEA) and nuclear matrix protein 22 (NMP22). In this immunosensor fabrication process, graphene oxide/polyaniline nanostructures are used as matrix and mesoporous NKF-5-3 is used as labels. Two kinds of antigens can be obtained from the signals of neutral red and toluidine blue, respectively, which are modified on the labels. In this tri-antibody dual-channel biosensing platform, sulfur-doped graphene sheet is synthesized by click chemistry as the framework structure. Majority of the incubations are conducted in individual steps, which ensure the surface incubation more tightly. The detection limit of NMP22 and CEA are 25 and 30 fg/mL, respectively. The low detection limit and excellent stability can ascribe to the tri-antibody dual-channel strategy, which makes the sensor platform from surface to the space. The clinical urine sample analysis achieves a good performance. The urine-based test can avoid the secondary injury on hemophilia or ischemic patients, displaying a potential application in clinical diagnosis.

Nanobody-Based Apolipoprotein E Immunosensor for Point-of-Care Testing

Alzheimer's disease (AD) biomarkers can reflect the neurochemical indicators used to estimate the risk in clinical nephrology. Apolipoprotein E (ApoE) is an early biomarker for AD in clinical diagnosis. In this research, through bactrian camel immunization, lymphocyte isolation, RNA extraction, and library construction, ApoE-specific Nbs with high affinity were successfully separated from an immune phage display nanobody library. Herein, a colorimetric immunosensor was developed for the point-of-care testing of ApoE by layer-by-layer nanoassembly techniques and novel nanobodies (Nbs). Using highly oriented Nbs as the capture and detection antibodies, an on-site immunosensor was developed by detecting the mean gray value of fade color due to the glutaraldehyde@3-aminopropyltrimethoxysilane oxidation by H₂O₂. The detection limit of AopE is 0.42 pg/mL, and the clinical analysis achieves a good performance. The novel easily operated immunosensor may have potential application in the clinical diagnosis and real-time monitoring for AD.

A novel sandwich-type immunosensor based on three-dimensional graphene–Au aerogels and quaternary chalcogenide nanocrystals for the detection of carcino embryonic antigen

Cu₂ZnSnS₄ nanocrystals were firstly used as electrocatalysts in H₂O₂ reduction for ultrasensitive detection of carcino embryonic antigen.

An ultrasensitive electrochemical immunosensor based on the synergistic effect of quaternary Cu2SnZnS4 NCs and cyclodextrin-functionalized graphene

Cu₂ZnSnS₄ nanocrystals were first used as electrocatalysts for H₂O₂ reduction for the ultrasensitive detection of alpha-fetoprotein.

Ultrasensitive sandwich-type electrochemical immunosensor based on trimetallic nanocomposite signal amplification strategy for the ultrasensitive detection of CEA

A novel and ultrasensitive sandwich-type electrochemical immunosensor was designed for the quantitative detection of carcino-embryonic antigen (CEA). This immunosensor was developed by using the trimetallic NiAuPt nanoparticles on graphene nanosheets (NGs) nanosheets (NiAuPt-NGs) as excellent labels and β-cyclodextrin functionalized reduced graphene oxide nanosheets (CD-NGs) as the platform. The CD-NGs with high specific surface area good biocompatibility and the ideal dispersibility was used to capture the primary antibodies (Ab1) efficiently. The trimetallic NiAuPt-NGs nanocomposites were used as the labels for signal amplification, showing better electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2), which is much better than that the monometallic Pt-NGs, bimetallic NiPt-NGs and AuPt-NGs due to the synergetic effect presented in NiAuPt-NGs. The NiAuPt-NGs nanocomposites consist of tightly coupled nanostructures of Au, Ni and Pt, which have neither an alloy nor a core-shell structure. Under the optimal conditions, a linear range from 0.001-100 ng/mL and a low detection limit of 0.27 pg/mL were obtained for CEA. The proposed electrochemical sandwich-type immunosensor may have a promising application in bioassay and it enriches the electrochemical immunoassays.

Influence of Ni on enhanced catalytic activity of Cu/Co3O4 towards reduction of nitroaromatic compounds: studies on the reduction kinetics

Addition of Ni significantly enhances the reaction rates of Cu/Co₃O₄ for the catalytic reduction of nitroaromatic compounds.

An ultrasensitive sandwich-type electrochemical immunosensor based on δ-MnO2 and palladium nanoparticles covered natural halloysite nanotubes for the detection of hepatitis B surface antigen

An ultrasensitive sandwich-type immunosensor for the detection of HBsAg based on the multifunctional natural halloysite nanotube nanocomposites (Pd/δ-MnO₂/HNTs).

A porous CuO nanowire-based signal amplification immunosensor for the detection of carcinoembryonic antigens

A novel electrochemical immunosensor was developed for the detection of CEA based on CNTs–AuNPs as a platform and pCuOw@Fc as labels. The immunosensor showed enhanced electrochemical performance toward the detection of CEA.

Corallite-like Magnetic Fe3O4@MnO2@Pt Nanocomposites as Multiple Signal Amplifiers for the Detection of Carcinoembryonic Antigen

A nonenzymatic sandwich-type electrochemical immunosensor using corallite-like magnetic Fe3O4@MnO2@Pt nanocomposites was developed for the sensitive detection of carcinoembryonic antigen (CEA). First, aminated graphene (GS-NH2) sheets were synthesized from graphite oxide using the Hummers' method, which was used to immobilize the primary antibody via the active amino groups on the GS-NH2. Second, corallite-like Fe3O4@MnO2@Pt nanoparticles (NPs) were synthesized and characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS). They were used as labels to conjugate with a secondary antibody. The multiple amplification of Fe3O4@MnO2@Pt NPs and the promoted electron transfer of GS-NH2 lead to a broad linear range from 0.5 pg/mL to 20 ng/mL and a low detection limit with 0.16 pg/mL. In addition, the immunosensor performed with good selectivity and acceptable stability and reproducibility as well. The results are satisfactory when the proposed method has been applied to analyze human serum samples. Thus, there would be a promising future in the early diagnosis of cancer to detect CEA and other tumor markers.

Combination of dynamic magnetophoretic separation and stationary magnetic trap for highly sensitive and selective detection of Salmonella typhimurium in complex matrix

Foodborne illnesses have always been a serious problem that threats public health, so it is necessary to develop a method that can detect the pathogens rapidly and sensitively. In this study, we designed a magnetic controlled microfluidic device which integrated the dynamic magnetophoretic separation and stationary magnetic trap together for sensitive and selective detection of Salmonella typhimurium (S. typhimurium). Coupled with immunomagnetic nanospheres (IMNs), this device could separate and enrich the target pathogens and realize the sensitive detection of target pathogens on chip. Based on the principle of sandwich immunoassays, the trapped target pathogens identified by streptavidin modified QDs (SA-QDs) were detected under an inverted fluorescence microscopy. A linear range was exhibited at the concentration from 1.0×10(4) to 1.0×10(6) colony-forming units/mL (CFU/mL), the limit of detection (LOD) was as low as 5.4×10(3) CFU/mL in milk (considering the sample volume, the absolute detection limit corresponded to 540C FU). Compared with the device with stationary magnetic trap alone, the integrated device enhanced anti-interference ability and increased detection sensitivity through dynamic magnetophoretic separation, and made the detection in complex samples more accurate. In addition, it had excellent specificity and good reproducibility. The developed system provides a rapid, sensitive and accurate approach to detect pathogens in practice samples.

Ultrasensitive immunoassay for CA125 detection using acid site compound as signal and enhancer

A novel sensitive electrochemical immunosensor was proposed for detection of CA125 based on ferrocenecarboxylic acid (FA), HCl-doped polyaniline (H-PANI) and chitosan hydrochloride (CS-HCl), which were used as substrate materials to generate signal and to enlarge specific surface area. The composite of these three materials (acid center compound, FA@H-PANI@CS-HCl) can be connected by hydrogen (H) in each molecule. Ag@Co3O4 nanosheets were used in the immunosensor to amplify the antibody capacity and to enhance the sensitivity of the immunoassay. This kind of sensor was novel, concise and it is the first time to be used in the detection of CA125. The biosensor exhibited low detection limit (0.25 pg/mL) and wide linear range (0.001-25 ng/mL). The stability, selectivity and reproducibility were acceptable. Serum sample analysis proved that the proposed sensor owned well precision and it might be used in potential clinic testing application in the future.

The multifaceted role of CD146/MCAM in the promotion of melanoma progression

Human malignant melanoma is a common primary malignant cutaneous tumour derived from transformed epidermal melanocytes. Patients with melanoma have a high rate of mortality due to resistance to chemotherapeutic drugs, a major obstacle to a successful treatment. Several reports have suggested that CD146 plays an important role as a signalling molecule in human melanoma. This role includes CD146 as a participant in inflammation, differentiation, adhesion, tumourigenicity, metastasis, invasion and angiogenesis among other processes, which suggests that this molecule promotes the progression of human melanoma as a multifaceted regulator. In this article, we explore the effects and corresponding mechanisms with respect to the role of CD146/MUC18 in the promotion of human melanoma progression. Collectively, the studies indicated that targeting CD146, because it is a suitable marker of poor patient outcome, might be useful in the design of future strategies for the prevention and treatment of human melanoma.

An ultrasensitive electrochemical immunosensor for the detection of CD146 based on TiO2 colloidal sphere laden Au/Pd nanoparticles

An ultrasensitive electrochemical immunosensor was developed for detecting CD146. rGO-TEPA enhanced the loading capacity of Ab₁ and facilitated the electron transfer. Au and Pd nanoparticles on the TiO₂ colloidal sphere facilitated the decomposition of H₂O₂. The immunosensor exhibited an extremely low detection limit of 1.6 pg mL⁻¹ for CD146.

An ultrasensitive electrochemical immunosensor for CEA using MWCNT-NH2 supported PdPt nanocages as labels for signal amplification

An ultrasensitive sandwich-type immunosensor was proposed by using MWCNT-NH₂ supported PdPt nanocages as labels for signal amplification.

A reusable microRNA sensor based on the electrocatalytic property of heteroduplex-templated copper nanoclusters

Repeat detection of miRNA is accomplished by reconstruction of DNA–RNA heteroduplexes-templated copper nanoclusters on an electrode surface.