Recent advances in optical biosensors for the detection of cancer biomarker α-fetoprotein (AFP)

A simple, rapid and sensitive sandwich immunoassay based on poly(N-isopropylacrylamide) for the detection of alpha-fetoprotein

Alpha-fetoprotein (AFP), as a tumor marker, plays a vital role in the diagnosis of liver cancer. In this work, a novel sandwich immunoassay based on a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), was developed for the detection of AFP. This immunoassay could realize one-step rapid reaction within 1 h, and facilitate the separation of the target molecules by incorporating PNIPAM. In this method, a conjugate of PNIPAM and capture antibody (Ab1) was successfully synthesized as a capture probe and the synthetic method of PNIPAM-Ab1 was simple, while the detection antibody (Ab2) was labeled with fluorescein isothiocyanate (FITC) to form a fluorescent detection probe. By employing a sandwich immunoassay, the method achieved quantitative determination of AFP, exhibiting a wide linear range from 5 ng/mL to 200 ng/mL and a low detection limit of 2.44 ng/mL. Furthermore, it was successfully applied to the analysis of spiked human serum samples and the screening of patients with hepatic diseases in clinical samples, indicating its potential application prospect in the diagnosis of liver cancer.

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.

Electrochemical immuno-biosensors for the detection of the tumor marker alpha-fetoprotein: A review

Alpha-fetoprotein (AFP) is a glycoprotein that has many important physiological functions, including transportation, immunosuppression, and induction of apoptosis by T lymphocytes. AFP is closely related to the development of hepatocellular carcinoma and many kinds of tumors, all of which can show high concentrations, so it is used as a positive test indicator for many kinds of tumors. This paper reviews recent advances in the detection of the tumor marker AFP based on three immuno-biosensors: electrochemical (EC), photoelectrochemical (PEC), and electrochemical luminescence (ECL). The electrodes are modified by different materials or homemade composites, different signaling molecules are selected as single probes or dual probes for the detection of AFP. The detection limit was as low as 3 fg/mL, which indicated that the AFP immunosensor had achieved highly sensitive detection. In addition, we also reviewed and summarized the current development status and application prospect of AFP immunoelectrochemical sensors. There are not too many researches on immunosensors based on dual-signal ratios, and the commonly used probes are methylene blue (MB) and ferrocene (Fc). It would be more innovative to have more novel signaling molecules as probes to prepare dual-signal ratio sensors.

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.

Oxygen Vacancies-Induced Antifouling Photoelectrochemical Aptasensor for Highly Sensitive and Selective Determination of α-Fetoprotein

Accurate measurement of cancer markers in urine is a convenient method for tumor monitoring. However, the concentration of cancer markers in urine is so low that it is difficult to achieve their measurement. Photoelectrochemical (PEC) sensors are a promising technology to realize the detection of trace cancer markers due to their high sensitivity. Currently, the interference of nonspecific biomolecules in urine is the main reason affecting the high sensitivity and selectivity of PEC sensors in detecting cancer markers. In this work, a strategy of oxygen vacancy (OV) modulation is proposed to construct a fouling-resistant PEC aptamer sensing platform for the detection of α-fetoprotein (AFP), a liver cancer marker. The introduction of OVs induces the formation of intermediate localized states in the photoelectric material, which not only facilitates the separation of photogenerated carriers but also leads to the redshift of the light absorption edge. More importantly, OVs with positive electrical properties can be employed to modify the antifouling layer (C-PEG) with negatively charged groups through an electrostatic interaction. The synergistic effect of OVs, antifouling layer, and aptamer resulted in a TiO2/OVs/C-PEG-based PEC sensor achieves a wide linear range from 1 pg/mL to 100 ng/mL and a low detection limit of 0.3 pg/mL for AFP. In addition, the sensor successfully realized the determination of AFP in urine samples and accurately differentiated between normal people and liver cancer patients in the early and advanced stages. This project is of great significance in advancing the application of photoelectrochemical bioanalytical technology to achieve the detection of cancer markers in urine by investigating the construction of an OVs-regulated fouling-resistant sensing interface.

Advances in human reproductive biomarkers

Reproductive biomarkers are important regulators in women, especially during pregnancy and childbirth. Because of their essential role in women's health, the discovery and quantification of reproductive biomarkers is of great clinical importance. Nowadays, there are many detection strategies to detect these biomarkers, including VEGF, human chorionic gonadotropin (hCG), etc. Consider the limitations and problems of conventional diagnostic methods, new methods are being developed, one of the most important being methods based on nanotechnology. This review includes a review of methods for diagnosing reproductive biomarkers, ranging from mainstream to nanotechnology-based methods. The bulk of this article is an in-depth introduction to the latest advances in biosensor and nanosensor research for the detection and quantitative identification of reproductive biomarkers.

Nanobody based immunoassay for alpha fetal protein detection using streptavidin-conjugated polymerized horseradish peroxidase for signal amplification

The enzyme-linked immunosorbent assay (ELISA) offers several advantages, including simple operation, high throughput, and low cost, making it an ideal immunoassay method for efficient screening of disease-related biomarkers in clinical samples. However, the traditional colorimetric ELISA has relatively low sensitivity, which promotes the continuous emergence of various novel signal amplification technologies. In this work, we fused the AFP-specific nanobody (A1) with the streptavidin-binding peptide (SBP) to develop a fusion protein (A1-SBP) as biorecognition element in a colorimetric ELISA for detecting AFP. Besides, to further improve the sensitivity of the traditional colorimetric ELISA, the streptavidin-conjugated polymerized horseradish peroxidase (SA-PolyHRP) were selected as a detection probe for signal amplification. The proposed signal enhancement strategy demonstrated a limit of detection (LOD) of 0.597 ng/mL for the SA-polyHRP-based ELISA, which is 7.67-fold lower than that of the traditional SA-HRP-based ELISA without additional steps. Furthermore, the proposed SA-polyHRP-based ELISA showed a good correlation with the detection of clinical samples using the Roche E601 chemiluminescence immunoassay analyzer. Therefore, the proposed signal enhancement strategy is an attractive approach for improving the sensitivity of immunoassay without requiring additional steps.

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.

Label-Free Homogeneous Electrochemical Aptasensor Based on Size Exclusion/Charge-Selective Permeability of Nanochannel Arrays and 2D Nanorecognitive Probe for Sensitive Detection of Alpha-Fetoprotein

The labeling-free and immobilization-free homogeneous aptamer sensor offers advantages including simple operation, low cost, and high sensitivity, demonstrating great potential in rapid detection of tumor biomarkers in biological samples. In this work, a labeling-free and immobilization-free homogeneous aptamer sensor was conveniently fabricated by combining size exclusion and charge-selective penetration of a nanochannel-modified electrode and two-dimensional (2D) nanorecognition probe which can realize selective and highly sensitive detection of alpha-fetoprotein (AFP) in serum. Vertically ordered mesoporous silica film (VMSF) with ultra-small, uniform, and vertically aligned nanochannels was easily grown on the simple, low-cost, and disposable indium tin oxide (ITO) electrode. Through π-π interaction and electrostatic force, the AFP aptamer (Apt) and electrochemical probe, tris(bipyridine)ruthenium(II) (Ru(bpy)32+), were coloaded onto graphene oxide (GO) through simple incubation, forming a 2D nanoscale recognition probe (Ru(bpy)32+/Apt@GO). Owing to the size exclusion effect of VMSF towards the 2D nanoscale probe, the electrochemical signal of Ru(bpy)32+/Apt@GO could not be detected. In the presence of AFP, the specific binding of AFP to the aptamer causes the dissociation of the aptamer and Ru(bpy)32+ from GO, resulting in their presence in the solution. The efficient electrostatic enrichment towards Ru(bpy)32+ by negatively charged VMSF allows for high electrochemical signals of free Ru(bpy)32+ in the solution. Linear determination of AFP ranged from 1 pg/mL to 1000 ng/mL and could be obtained with a low limit of detection (LOD, 0.8 pg/mL). The high specificity of the adapter endowed the constructed sensor with high selectivity. The fabricated probe can be applied in direct determination of AFP in serum.

Nanozyme-Catalyzed Metasurface Plasmon Sensor-Based Portable Ultrasensitive Optical Quantification Platform for Cancer Biomarker Screening

Developing plasmonic biosensors that are low-cost, portable, and relatively simple to operate remains challenging. Herein, a novel metasurface plasmon-etch immunosensor is described, namely a nanozyme-linked immunosorbent surface plasmon resonance biosensor, for the ultrasensitive and specific detection of cancer biomarkers. Gold-silver composite nano cup array metasurface plasmon resonance chip and artificial nanozyme-labeled antibody are used in two-way sandwich analyte detection. Changes in the biosensor's absorption spectrum are measured before and after chip surface etching, which can be applied to immunoassays without requiring separation or amplification. The device achieved a limit of alpha-fetoprotein (AFP) detection < 21.74 fM, three orders of magnitude lower than that of commercial enzyme-linked immunosorbent assay kits. Additionally, carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125) are used for quantitative detection to verify the universality of the platform. More importantly, the accuracy of the platform is verified using 60 clinical samples; compared with the hospital results, the three biomarkers achieve high sensitivity (CEA: 95.7%; CA125: 90.9%; AFP: 86.7%) and specificity (CEA: 97.3%; CA125: 93.9%; AFP: 97.8%). Due to its rapidity, ease of use, and high throughput, the platform has the potential for high-throughput rapid detection to facilitate cancer screening or early diagnostic testing in biosensing.

Recent Advances in Nanomaterials-Based Targeted Drug Delivery for Preclinical Cancer Diagnosis and Therapeutics

Nano-oncology is a branch of biomedical research and engineering that focuses on using nanotechnology in cancer diagnosis and treatment. Nanomaterials are extensively employed in the field of oncology because of their minute size and ultra-specificity. A wide range of nanocarriers, such as dendrimers, micelles, PEGylated liposomes, and polymeric nanoparticles are used to facilitate the efficient transport of anti-cancer drugs at the target tumor site. Real-time labeling and monitoring of cancer cells using quantum dots is essential for determining the level of therapy needed for treatment. The drug is targeted to the tumor site either by passive or active means. Passive targeting makes use of the tumor microenvironment and enhanced permeability and retention effect, while active targeting involves the use of ligand-coated nanoparticles. Nanotechnology is being used to diagnose the early stage of cancer by detecting cancer-specific biomarkers using tumor imaging. The implication of nanotechnology in cancer therapy employs photoinduced nanosensitizers, reverse multidrug resistance, and enabling efficient delivery of CRISPR/Cas9 and RNA molecules for therapeutic applications. However, despite recent advancements in nano-oncology, there is a need to delve deeper into the domain of designing and applying nanoparticles for improved cancer diagnostics.

Nanopore Single-molecule Analysis of Biomarkers: Providing Possible Clues to Disease Diagnosis

Biomarker detection has attracted increasing interest in recent years due to the minimally or non-invasive sampling process. Single entity analysis of biomarkers is expected to provide real-time and accurate biological information for early disease diagnosis and prognosis, which is critical to the effective disease treatment and is also important in personalized medicine. As an innovative single entity analysis method, nanopore sensing is a pioneering single-molecule detection technique that is widely used in analytical bioanalytical fields. In this review, we overview the recent progress of nanopore biomarker detection as new approaches to disease diagnosis. In highlighted studies, nanopore was focusing on detecting biomarkers of different categories of communicable and noncommunicable diseases, such as pandemic Covid-19, AIDS, cancers, neurologic diseases, etc. Various sensitive and selective nanopore detecting strategies for different types of biomarkers are summarized. In addition, the challenges, opportunities, and direction for future development of nanopore-based biomarker sensors are also discussed.

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.

A simple, sensitive, label-free electrochemical immunosensor based on the chitosan-coated silver/cerium oxide (CS@Ag/CeO2) nanocomposites for the detection of alpha-fetoprotein (AFP)

Metal oxide-based sensors have the benefit of inexpensive, quick response, and high sensitivity in detecting specific biological species. In this article, a simple electrochemical immunosensor was fabricated using antibody-chitosan coated silver/cerium oxide (Ab-CS@Ag/CeO₂) nanocomposites on a gold electrode for sensitive alpha-fetoprotein (AFP) diagnosis in human serum samples. Successfully synthesis of AFP antibody-CS@Ag/CeO₂conjugates was confirmed through Fourier transform infrared spectra of the prototype. The amine coupling bond chemistry was then used to immobilize the resultant conjugate on a gold electrode surface. It was observed that the interaction of the synthesized Ab-CS@Ag/CeO₂nanocomposites with AFP prevented an electron transfer and reduced the voltammetric Fe(CN)₆^3-/4-peak current, which was proportional to the amount of AFP. The linear ranges of AFP concentration were found from 10^-12-10^-6g.ml^-1. The limit of detection was calculated using the calibration curve and came out to be 0.57 pg.ml^-1. The designed label-free immunosensor successfully detected AFP in human serum samples. As a result, the resulting immunosensor is a promising sensor plate form for AFP detection and could be used in clinical bioanalysis.

Rational design of nonlinear hybridization immunosensor chain reactions for simultaneous ultrasensitive detection of two tumor marker proteins

Sensitive biomarker detection techniques are beneficial for both disease diagnosis and postoperative examinations. The nonlinear hybridization chain reaction (NHCR) is widely used as an output signal amplification technique for biosensor platforms. A novel hairpin-free NHCR was developed in this study as a flow cytometric immunoassay to detect alpha-fetoprotein (AFP) and prostate specific antigen (PSA). First, the target AFP is captured on magnetic beads (MBs) that are modified with capture antibodies. Then, the prepared biotin-streptavidin-biotin (B-S-B) system, which links biotinylated detection antibodies and biotinylated trigger DNA together through the high affinity between biotin-streptavidin interaction, is added to label the target AFP, forming a sandwich complex with three trigger DNA chains. Each trigger DNA chain grows a dendritic DNA nanostructure following a nonlinear hybridization chain reaction. As the substrate flue chains are labeled with fluorophores, the self-assembly process of dendritic DNA is accompanied by the continuous release of fluorophores. Dendrites with strong fluorescence then form on the surface of MBs. Finally, the target AFP is quantified by analyzing the fluorescent MBs using flow cytometry. The proposed immunoassay has a high selectivity along with isothermal, enzyme-free, and exponential amplification efficiency. It shows a limit of detection (LOD) of 1.74 pg mL^-1. The proposed biosensor was also successfully used to quantitatively detect AFP in serum samples. It may be utilized to detect multiple tumor markers simultaneously by changing the size of MBs and antibody-antigen pairs. Most tumor markers are only related to tumor diagnosis but without specificity, so the combined detection of multiple tumor markers can improve the accuracy of early tumor diagnoses.

Microfluidic platforms integrated with nano-sensors for point-of-care bioanalysis

Microfluidic technology provides a portable, cost-effective, and versatile tool for point-of-care (POC) bioanalysis because of its associated advantages such as fast analysis, low volumes of reagent consumption, and high portability. Along with microfluidics, the application of nanomaterials in biosensing has attracted lots of attention due to their unique physical and chemical properties for enhanced signal modulation such as signal amplification and signal transduction for POC bioanalysis. Hence, an enormous number of microfluidic devices integrated with nano-sensors have been developed for POC bioanalysis targeting low-resource settings. Herein, we review recent advances in POC bioanalysis on nano-sensor-based microfluidic platforms. We first briefly summarized the different types of cost-effective microfluidic platforms, followed by a concise introduction to nanomaterial-based biosensors. Then, we highlighted the application of microfluidic platforms integrated with nano-sensors for POC bioanalysis. Finally, we discussed the current limitations and perspective trends of the nano-sensor-based microfluidic platforms for POC bioanalysis.

Dual-mode electrochemiluminescence and electrochemical sensor for alpha-fetoprotein detection in human serum based on vertically ordered mesoporous silica films

In this study, we demonstrated the highly sensitive detection of alpha-fetoprotein (AFP) by electrochemiluminescence (ECL) and electrochemistry (EC) based on the gated transport of the bifunctional probe (tris(1,10-phenanthroline) ruthenium (II) chloride, Ru (phen)₃Cl₂) into the nanochannels of vertically ordered mesoporous silica films (VMSFs). Due to the negatively charged surface and ultrasmall pore size, VMSF displays a signal amplification effect on Ru (phen)₃Cl₂ and is suitable for the construction of sensors with excellent sensitivity. With the linkage of (3-glycidyloxypropyl) trimethoxysilane, the anti-AFP antibody could covalently bind to the external surface of VMSF, generating a highly specific recognized sensing interface toward AFP. When AFP is presented, the formed immunocomplex hinders the diffusion of Ru (phen)₃Cl₂ to the underlying electrode surface, resulting in a decreased ECL or EC response. The dual-mode detection of AFP is achieved with a relatively low limit of detection (0.56 fg/ml for ECL and 4.5 pg/ml for EC) and a wide linear range (10 fg/ml∼1 μg/ml for ECL and 10 pg/ml∼1 μg/ml for EC). Moreover, owing to the inherent anti-fouling property of VMSF, satisfactory results in the analysis of human serum were obtained, showing the great potential of the designed strategy in clinical diagnosis.

Nanotechnology: A Promising Approach for Cancer Diagnosis, Therapeutics and Theragnosis

Cancer remains the most devastating disease and the major cause of mortality worldwide. Although early diagnosis and treatment are the key approach in fighting against cancer, the available conventional diagnostic and therapeutic methods are not efficient. Besides, ineffective cancer cell selectivity and toxicity of traditional chemotherapy remain the most significant challenge. These limitations entail the need for the development of both safe and effective cancer diagnosis and treatment options. Due to its robust application, nanotechnology could be a promising method for in-vivo imaging and detection of cancer cells and cancer biomarkers. Nanotechnology could provide a quick, safe, cost-effective, and efficient method for cancer management. It also provides simultaneous diagnosis and treatment of cancer using nano-theragnostic particles that facilitate early detection and selective destruction of cancer cells. Updated and recent discussions are important for selecting the best cancer diagnosis, treatment, and management options, and new insights on designing effective protocols are utmost important. This review discusses the application of nanotechnology in cancer diagnosis, therapeutics, and theragnosis and provides future perspectives in the field.

Hemin-graphene oxide-gold nanoflower-assisted enhanced electrochemiluminescence immunosensor for determination of prostate-specific antigen

An ultrasensitive luminol electrochemiluminescence (ECL) immunosensor was constructed for the detection of prostate specific antigen (PSA) using glucose oxidase-decorated hemin-graphene oxide-gold nanoflowers ternary nanocomposites as probes. Graphene oxide was first modified with hemin and then with gold nanoflowers through an in situ growth method, which has significantly boosted the catalytic activity of this graphene oxide-based peroxidase mimetics. The biocatalytical activity of this ECL immunosensor was thoroughly investigated to achieve selective recognition of the analyte molecules (PSA) by specific binding between antigens and antibodies. The limit of detection was calculated to be 0.32 pg mL^-1 with a signal-to-noise ratio of 3. A broad linear range from 7.5 × 10^-4 to 2.5 ng mL^-1 was obtained. Such step-by-step assembled biosensor showed controlled nanostructure and exhibited promising application in analysis of human serum samples with a recovery range of 90.6-111.8% and a RSD range of 3.9-5.5%.

Highly Sensitive Love Mode Acoustic Wave Platform with SiO2 Wave-Guiding Layer and Gold Nanoparticles for Detection of Carcinoembryonic Antigens

A highly sensitive and precise Love wave mode surface acoustic wave (SAW) immunosensor based on an ST-cut 90°X quartz substrate and an SiO₂ wave-guiding layer was developed to detect cancer-related biomarkers of carcinoembryonic antigens (CEAs). A delay line structure of the SAW device with a resonant frequency of 196 MHz was designed/fabricated, and its surface was functionalized through CEA antibody immobilization. The CEA antibodies were bound with gold nanoparticles and CEA antibodies to form a sandwich structure, which significantly amplified the mass loading effect and enhanced the maximum responses by 30 times. The center frequency of the Love wave immunosensor showed a linear response as a function of the CEA concentration in the range of 0.2–5 ng/mL. It showed a limit of detection of 0.2 ng/mL, and its coefficient of determination was 0.983. The sensor also showed minimal interference from nonspecific adsorptions, thus demonstrating its promise for point-of-care applications for cancer biomarkers.

Emerging biosensing and transducing techniques for potential applications in point-of-care diagnostics

With the deepening of our understanding in life science, molecular biology, nanotechnology, optics, electrochemistry and other areas, an increasing number of biosensor design strategies have emerged in recent years, capable of providing potential practical applications for point-of-care (POC) diagnosis in various human diseases. Compared to conventional biosensors, the latest POC biosensor research aims at improving sensor precision, cost-effectiveness and time-consumption, as well as the development of versatile detection strategies to achieve multiplexed analyte detection in a single device and enable rapid diagnosis and high-throughput screening. In this review, various intriguing strategies in the recognition and transduction of POC (from 2018 to 2021) are described in light of recent advances in CRISPR technology, electrochemical biosensing, and optical- or spectra-based biosensing. From the perspective of promoting emerging bioanalytical tools into practical POC detecting and diagnostic applications, we have summarized key advances made in this field in recent years and presented our own perspectives on future POC development and challenges.

A Review of Biosensors for Detecting Tumor Markers in Breast Cancer

Breast cancer has the highest cancer incidence rate in women. Early screening of breast cancer can effectively improve the treatment effect of patients. However, the main diagnostic techniques available for the detection of breast cancer require the corresponding equipment, professional practitioners, and expert analysis, and the detection cost is high. Tumor markers are a kind of active substance that can indicate the existence and growth of the tumor. The detection of tumor markers can effectively assist the diagnosis and treatment of breast cancer. The conventional detection methods of tumor markers have some shortcomings, such as insufficient sensitivity, expensive equipment, and complicated operations. Compared with these methods, biosensors have the advantages of high sensitivity, simple operation, low equipment cost, and can quantitatively detect all kinds of tumor markers. This review summarizes the biosensors (2013–2021) for the detection of breast cancer biomarkers. Firstly, the various reported tumor markers of breast cancer are introduced. Then, the development of biosensors designed for the sensitive, stable, and selective recognition of breast cancer biomarkers was systematically discussed, with special attention to the main clinical biomarkers, such as human epidermal growth factor receptor-2 (HER2) and estrogen receptor (ER). Finally, the opportunities and challenges of developing efficient biosensors in breast cancer diagnosis and treatment are discussed.

Fabricated Metal-Organic Frameworks (MOFs) as luminescent and electrochemical biosensors for cancer biomarkers detection

In the health domain, a major challenge is the detection of diseases using rapid and cost-effective techniques. Most of the existing cancer detection methods show poor sensitivity and selectivity and are time consuming with high cost. To overcome this challenge, we analyzed porous fabricated metal-organic frameworks (MOFs) that have better structures and porosities for enhanced biomarker sensing. Here, we summarize the use of fabricated MOF luminescence and electrochemical sensors in devices for cancer biomarker detection. Various strategies of fabrication and the role of fabricated materials in sensing cancer biomarkers have been studied and described. The structural properties, sensing mechanisms, roles of noncovalent interactions, limits of detection, modeling, advantages, and limitations of MOF sensors have been well-discussed. The study presents an innovative technique to detect the cancer biomarkers by the use of luminescence and electrochemical MOF sensors. In addition, the potential association studies have been opening the way for personalized patient treatments and the development of new cancer-detecting devices.

Etching reaction of carbon quantum dot-functionalized MnO2 nanosheets with an enzymatic product for photoelectrochemical immunoassay of alpha-fetoprotein

An etching reaction-based photoelectrochemical (PEC) immunoassay was developed to monitor alpha-fetoprotein (AFP) by coupling with the enzymatic product toward the dissolution of MnO2 nanosheets.

Ion-selective electrode-based potentiometric immunoassays for the quantitative monitoring of alpha-fetoprotein by coupling rolling cycle amplification with silver nanoclusters

This work reports an ion-selective electrode-based potentiometric immunoassay for AFP detection coupling rolling cycle amplification with silver nanoclusters.

The importance of precision medicine in modern molecular oncology

With the rapid development of modern medical technology, information data modeling has been gradually applied to clinical diagnosis and treatment. Precision medicine is an important approach that focuses on individual patients in terms of their own characteristics, genomic information, proteomics and even social environments. Genome-wide high-throughput technologies, including DNA-seq, RNA-seq, exosome-seq…, contribute enormous amounts of molecular data to aid in diagnosis and analysis. Here, we review the developmental history of different next-generation sequencing platforms, introduce their applications in different tumor diagnosis and therapy, and further discuss the remaining challenges in precision medicine.