Towards intrinsic graphene biosensor: A label-free, suspended single crystalline graphene sensor for multiplex lung cancer tumor markers detection

Nano-Assisted Radiotherapy Strategies: New Opportunities for Treatment of Non-Small Cell Lung Cancer

Lung cancer is the second most commonly diagnosed cancer and a leading cause of cancer-related death, with non-small cell lung cancer (NSCLC) being the most prevalent type. Over 70% of lung cancer patients require radiotherapy (RT), which operates through direct and indirect mechanisms to treat cancer. However, RT can damage healthy tissues and encounter radiological resistance, making it crucial to enhance its precision to optimize treatment outcomes, minimize side effects, and overcome radioresistance. Integrating nanotechnology into RT presents a promising method to increase its efficacy. This review explores various nano-assisted RT strategies aimed at achieving precision treatment. These include using nanomaterials as radiosensitizers, applying nanotechnology to modify the tumor microenvironment, and employing nano-based radioprotectors and radiation-treated cell products for indirect cancer RT. We also explore recent advancements in nano-assisted RT for NSCLC, such as biomimetic targeting that alters mesenchymal stromal cells, magnetic targeting strategies, and nanosensitization with high-atomic number nanomaterials. Finally, we address the existing challenges and future directions of precision RT using nanotechnology, highlighting its potential clinical applications.

An insight into biosensing platforms used for the diagnosis of various lung diseases: A review

Many of the infectious diseases are ubiquitous in nature and pose a threat to global and public health. The original cause for such type of serious maladies can be summarized as the scarcity of appropriate analysis and treatment methods. Pulmonary diseases are considered one of the life-threatening lung diseases that affect millions of people globally. It consists of several types, namely, asthma, lung cancer, tuberculosis, chronic obstructive pulmonary disease, and several respiratory-related infections. This is due to the limited access to well-equipped healthcare facilities for early disease diagnosis. This needs the availability of processes and technologies that can help to stop this harmful disease-diagnosing practice. Various approaches for diagnosing various lung diseases have been developed over time, namely, autopsy, chest X-rays, low-dose CT scans, and so forth. The need of the hour is to develop a rapid, simple, portable, and low-cost method for the diagnosis of pulmonary diseases. So nowadays, biosensors have been becoming one of the highest priority research areas as a potentially useful tool for the early diagnosis and detection of many pulmonary lung diseases. In this review article, various types of biosensors and their applications in the diagnosis of lung-related disorders are expansively explained.

Strategies and Applications of Graphene and Its Derivatives-Based Electrochemical Sensors in Cancer Diagnosis

Graphene is an emerging nanomaterial increasingly being used in electrochemical biosensing applications owing to its high surface area, excellent conductivity, ease of functionalization, and superior electrocatalytic properties compared to other carbon-based electrodes and nanomaterials, enabling faster electron transfer kinetics and higher sensitivity. Graphene electrochemical biosensors may have the potential to enable the rapid, sensitive, and low-cost detection of cancer biomarkers. This paper reviews early-stage research and proof-of-concept studies on the development of graphene electrochemical biosensors for potential future cancer diagnostic applications. Various graphene synthesis methods are outlined along with common functionalization approaches using polymers, biomolecules, nanomaterials, and synthetic chemistry to facilitate the immobilization of recognition elements and improve performance. Major sensor configurations including graphene field-effect transistors, graphene modified electrodes and nanocomposites, and 3D graphene networks are highlighted along with their principles of operation, advantages, and biosensing capabilities. Strategies for the immobilization of biorecognition elements like antibodies, aptamers, peptides, and DNA/RNA probes onto graphene platforms to impart target specificity are summarized. The use of nanomaterial labels, hybrid nanocomposites with graphene, and chemical modification for signal enhancement are also discussed. Examples are provided to illustrate applications for the sensitive electrochemical detection of a broad range of cancer biomarkers including proteins, circulating tumor cells, DNA mutations, non-coding RNAs like miRNA, metabolites, and glycoproteins. Current challenges and future opportunities are elucidated to guide ongoing efforts towards transitioning graphene biosensors from promising research lab tools into mainstream clinical practice. Continued research addressing issues with reproducibility, stability, selectivity, integration, clinical validation, and regulatory approval could enable wider adoption. Overall, graphene electrochemical biosensors present powerful and versatile platforms for cancer diagnosis at the point of care.

Organic electrochemical transistor-based immuno-sensor using platinum loaded CeO2 nanosphere-carbon nanotube and zeolitic imidazolate framework-enzyme-metal polyphenol network

This work demonstrates an organic electrochemical transistor (OECT) immuno-sensor with a detection limit down to fg mL^-1. The OECT device transforms the antibody-antigen interaction signal by using the zeolitic imidazolate framework-enzyme-metal polyphenol network nanoprobe, which can produce electro-active substance (H₂O₂) through the enzyme-catalytic reaction. The produced H₂O₂ is subsequently electrochemically oxidized at the platinum loaded CeO₂ nanosphere-carbon nanotube modified gate electrode, resulting in an amplified current response of the transistor device. This immuno-sensor realizes the selective determination of vascular endothelial growth factor 165 (VEGF₁₆₅) down to the concentration of 13.6 fg mL^-1. It also shows good applicable capacity for determining the VEGF₁₆₅ that human brain microvascular endothelial cells and U251 human glioblastomas cells secreted in the cell culture medium. The ultrahigh sensitivity of the immuno-sensor is derived from excellent performances of the nanoprobe for enzyme loading and the OECT device for H₂O₂ detection. This work may provide a general way to fabricate the OECT immuno-sensing device with high performances.

Surface plasmon resonance biosensor with laser heterodyne feedback for highly-sensitive and rapid detection of COVID-19 spike antigen

The ongoing outbreak of the COVID-19 has highlighted the importance of the pandemic prevention and control. A rapid and sensitive antigen assay is crucial in diagnosing and curbing pandemic. Here, we report a novel surface plasmon resonance biosensor based on laser heterodyne feedback interferometry for the detection of SARS-CoV-2 spike antigen, which is achieved by detecting the tiny difference in refractive index between different antigen concentrations. The biosensor converts the refractive index changes at the sensing unit into the intensity changes of light through surface plasmon resonance, achieving label-free and real-time detection of biological samples. Moreover, the gain amplification effect of the laser heterodyne feedback interferometry further improved the sensitivity of this biosensor. The biosensor can rapidly respond to continuous and periodic changes in the refractive index with a high resolution of 3.75 × 10-8 RIU, demonstrating the repeatability of the biosensor. Afterwards, the biosensor is immobilized by the anti-SARS-CoV-2 spike monoclonal antibodies, thus realizing the specific recognition of the antigen. The biosensor exhibited a high sensitivity towards the concentration of the antigen with a linear dynamic range of five orders of magnitude and a resolution of 0.08 pg/mL. These results indicate that this principle can be used as a rapid diagnostic method for COVID-19 antigens without sample labelling.

Dual-Signal-Encoded Barcodes with Low Background Signal for High-Sensitivity Analysis of Multiple Tumor Markers

The suspension array technology (SAT) is promising for high-sensitivity multiplexed analysis of tumor markers. Barcodes as the core elements of SAT, can generate encoding fluorescence signals (EFS) and detection fluorescence signals (DFS) in the corresponding flow cytometer channel. However, the bleed-through effect of EFS in the DFS channel and the reagent-driven non-specific binding (NSB) lead to background interference for ultrasensitive assay of multiple targets. Here, we report an ingenious method to eliminate background interference between barcode and reporter using low-background dual-signal-encoded barcodes (DSBs) based on microbeads (MBs) and quantum dots (QDs). The low-background DSBs were prepared via combination strategy of two signals containing scatter signals and fluorescence signals. Three types of MBs were distinguished by the scattering channel of flow cytometer (FSC vs. SSC) to obtain the scattered signals. Green quantum dots (GQDs) or red quantum dots (RQDs) were coupled to the surface of MBs by sandwich immune structure to obtain the distinguishable fluorescent signals. Furthermore, the amount of conjugated capture antibody on the MB’s surface was optimized by comparing the change of detection sensitivity with the addition of capture antibody. The combination measurements of specificity and NSB in SAT platform were performed by incubating the capture antibody-conjugated MBs (cAb-MBs) with individual QD-conjugated detection antibody (QDs-dAb). Finally, an SAT platform based on DSBs was successfully established for highly sensitive multiplexed analysis of six tumor markers in one test, which suggests the promising tool for highly sensitive multiplexed bioassay applications.

The Need to Pair Molecular Monitoring Devices with Molecular Imaging to Personalize Health

By enabling the non-invasive monitoring and quantification of biomolecular processes, molecular imaging has dramatically improved our understanding of disease. In recent years, non-invasive access to the molecular drivers of health versus disease has emboldened the goal of precision health, which draws on concepts borrowed from process monitoring in engineering, wherein hundreds of sensors can be employed to develop a model which can be used to preventatively detect and diagnose problems. In translating this monitoring regime from inanimate machines to human beings, precision health posits that continual and on-the-spot monitoring are the next frontiers in molecular medicine. Early biomarker detection and clinical intervention improves individual outcomes and reduces the societal cost of treating chronic and late-stage diseases. However, in current clinical settings, methods of disease diagnoses and monitoring are typically intermittent, based on imprecise risk factors, or self-administered, making optimization of individual patient outcomes an ongoing challenge. Low-cost molecular monitoring devices capable of on-the-spot biomarker analysis at high frequencies, and even continuously, could alter this paradigm of therapy and disease prevention. When these devices are coupled with molecular imaging, they could work together to enable a complete picture of pathogenesis. To meet this need, an active area of research is the development of sensors capable of point-of-care diagnostic monitoring with an emphasis on clinical utility. However, a myriad of challenges must be met, foremost, an integration of the highly specialized molecular tools developed to understand and monitor the molecular causes of disease with clinically accessible techniques. Functioning on the principle of probe-analyte interactions yielding a transducible signal, probes enabling sensing and imaging significantly overlap in design considerations and targeting moieties, however differing in signal interpretation and readout. Integrating molecular sensors with molecular imaging can provide improved data on the personal biomarkers governing disease progression, furthering our understanding of pathogenesis, and providing a positive feedback loop toward identifying additional biomarkers and therapeutics. Coupling molecular imaging with molecular monitoring devices into the clinical paradigm is a key step toward achieving precision health.

Biosensors and nanotechnology for cancer diagnosis (lung and bronchus, breast, prostate, and colon): a systematic review

The second cause of death in the world has been reported to be cancer, and it has been on the rise in recent years. As a result of the difficulties of cancer detection and its treatment, the survival rate of patients is unclear. The early detection of cancer is an important issue for its therapy. Cancer detection based on biomarkers may effectively enhance the early detection and subsequent treatment. Nanomaterial-based nanobiosensors for cancer biomarkers are excellent tools for the molecular detection and diagnosis of disease. This review reports the latest advancement and attainment in applying nanoparticles to the detection of cancer biomarkers. In this paper, the recent advances in the application of common nanomaterials like graphene, carbon nanotubes, Au, Ag, Pt, and Fe₃O₄together with newly emerged nanoparticles such as quantum dots, upconversion nanoparticles, inorganics (ZnO, MoS₂), and metal-organic frameworks for the diagnosis of biomarkers related to lung, prostate, breast, and colon cancer are highlighted. Finally, the challenges, outlook, and closing remarks are given.

Exploring the mechanical properties of nanometer-thick elastic films through micro-drop impinging on large-area suspended graphene

In this work, the dependence of effective Young's modulus on the thickness of suspended graphene was confirmed through a drop impingement method. Large area suspended graphene (LSG) layers with a diameter of up to 400 μm and a nanometer thickness were prepared through transferring chemical vapor deposition grown graphene from copper substrates. 4, 8, and 12-layer LSG samples were found to be crumpled yet defect-free. The mechanical properties of LSG were first studied by observing its interaction with impinging droplets from an ink-jet nozzle. First, the effective Young's modulus was calculated by fitting the instant deformation captured by high speed photography within microseconds. Next, droplets deposited on LSG caused deformation and generated wrinkles and the effective Young's modulus was calculated from the number of wrinkles. The above methods yielded effective Young's modulus values ranging from 0.3 to 3.4 TPa. The results from these methods all indicated that the effective Young's modulus increases with the decreasing thickness or size of suspended graphene layers. Moreover, the crumpled LSG yields higher effective Young's modulus than ideal flat graphene. These comprehensive results from complementary methodologies with precise LSG thickness control down to the nanometer scale provide good evidence to resolve the debate on the thickness dependence of mechanical strength for LSG.

Graphene-Based Biosensors with High Sensitivity for Detection of Ovarian Cancer Cells

Ovarian cancer has the highest mortality rate in the world. Therefore, it is urgent but still challenging to develop an efficient circulating tumor cell (CTC) detection method to sensitively detect ovarian cancer. To address such issues, herein, for the first time, we present a novel CTC detection method for ovarian cancer cells by designing sensitive and rapid graphene-based biosensors. This graphene-based sensor, consisting of a cell pool and two electrodes, can be prepared by a conventional chip fabrication process. It demonstrates high-sensitivity detection even for several ovarian cancer cells by comparing the electrical signal before and after adding cell solution. Moreover, the graphene-based biosensors can perform rapid detection with good repeatability. This suggests that this novel method is possible to use for the early detection of ovarian cancer with very low CTC cell concentration. This work provides a novel and quick strategy to detect ovarian cancer and further judge or predict the risk of the transfer of ovarian cancer.

Liquid Biopsy-Based Biosensors for MRD Detection and Treatment Monitoring in Non-Small Cell Lung Cancer (NSCLC)

Globally, non-small cell lung cancer (NSCLC) is the leading cause of cancer deaths. Despite advancements in chemotherapy and targeted therapies, the 5-year survival rate has remained at 16% for the past forty years. Minimal residual disease (MRD) is described as the existence of either isolated tumour cells or circulating tumour cells in biological liquid of patients after removal of the primary tumour without any clinical signs of cancer. Recently, liquid biopsy has been promising as a non-invasive method of disease monitoring and treatment guidelines as an MRD marker. Liquid biopsy could be used to detect and assess earlier stages of NSCLC, post-treatment MRD, resistance to targeted therapies, immune checkpoint inhibitors (ICIs) and tumour mutational burden. MRD surveillance has been proposed as a potential marker for lung cancer relapse. Principally, biosensors provide the quantitative analysis of various materials by converting biological functions into quantifiable signals. Biosensors are usually operated to detect antibodies, enzymes, DNA, RNA, extracellular vesicles (EVs) and whole cells. Here, we present a category of biosensors based on the signal transduction method for identifying biosensor-based biomarkers in liquid biopsy specimens to monitor lung cancer treatment.

Wafer-scalable chemical modification of amino groups on graphene biosensors

Graphene's remarkable attributes make it suitable for application to biosensors for biomolecular recognition. Specific and precise target detection is realized by designing robust methods for immobilization of probe molecules, such as oligonucleotides, antibodies, receptors, and sugar chains, to a device surface. In this research, we developed a chemical modification method with a plasma treatment of amino groups on natural defects of graphene, which is compatible with a wafer-scalable semiconductor process, to prevent deterioration of the carrier mobility. The plasma treatment was optimized in terms of the efficiency of the amino radical generation, length of the mean free path, and reaction energy on graphene. The density of the modified amino groups on graphene was approximately 0.065 groups/nm², and the change in the ΔI_d/ΔV_g characteristic of the graphene field-effect transistor (FET) was negligible. DNA probes were then attached to the amino groups on the graphene FET. The target complementary DNA was detected at 1 nM after hybridization using the graphene FET devices. The plasma-assisted modification of the amino groups on the graphene surface was developed for immobilization of the DNA probes, and hybridization with the target DNA was demonstrated without deterioration of the carrier mobility.

Materials, Devices, and Systems of On-Skin Electrodes for Electrophysiological Monitoring and Human-Machine Interfaces

On-skin electrodes function as an ideal platform for collecting high-quality electrophysiological (EP) signals due to their unique characteristics, such as stretchability, conformal interfaces with skin, biocompatibility, and wearable comfort. The past decade has witnessed great advancements in performance optimization and function extension of on-skin electrodes. With continuous development and great promise for practical applications, on-skin electrodes are playing an increasingly important role in EP monitoring and human-machine interfaces (HMI). In this review, the latest progress in the development of on-skin electrodes and their integrated system is summarized. Desirable features of on-skin electrodes are briefly discussed from the perspective of performances. Then, recent advances in the development of electrode materials, followed by the analysis of strategies and methods to enhance adhesion and breathability of on-skin electrodes are examined. In addition, representative integrated electrode systems and practical applications of on-skin electrodes in healthcare monitoring and HMI are introduced in detail. It is concluded with the discussion of key challenges and opportunities for on-skin electrodes and their integrated systems.

Recent advances in graphene monolayers growth and their biological applications: A review

Development of two-dimensional high-quality graphene monolayers has recently received great concern owing to their enormous applications in diverging fields including electronics, photonics, composite materials, paints and coatings, energy harvesting and storage, sensors and metrology, and biotechnology. As a result, various groups have successfully developed graphene layers on different substrates by using the chemical vapor deposition method and explored their physical properties. In this direction, we have focused on the state-of-the-art developments in the growth of graphene layers, and their functional applications in biotechnology. The review starts with the introduction, which contains outlines about the graphene and their basic characteristics. A brief history and inherent applications of graphene layers followed by recent developments in growth and properties are described. Then, the application of graphene layers in biodevices is reviewed. Finally, the review is summarized with perspectives and future challenges along with the scope for future technological applications.

Ultrasensitive and Highly Selective Graphene-Based Field-Effect Transistor Biosensor for Anti-Diuretic Hormone Detection

Nephrogenic diabetes insipidus (NDI), which can be congenital or acquired, results from the failure of the kidney to respond to the anti-diuretic hormone (ADH). This will lead to excessive water loss from the body in the form of urine. The kidney, therefore, has a crucial role in maintaining water balance and it is vital to restore this function in an artificial kidney. Herein, an ultrasensitive and highly selective aptameric graphene-based field-effect transistor (GFET) sensor for ADH detection was developed by directly immobilizing ADH-specific aptamer on a surface-modified suspended graphene channel. This direct immobilization of aptamer on the graphene surface is an attempt to mimic the functionality of collecting tube V 2 receptors in the ADH biosensor. This aptamer was then used as a probe to capture ADH peptide at the sensing area which leads to changes in the concentration of charge carriers in the graphene channel. The biosensor shows a significant increment in the relative change of current ratio from 5.76 to 22.60 with the increase of ADH concentration ranging from 10 ag/mL to 1 pg/mL. The ADH biosensor thus exhibits a sensitivity of 50.00 µA· ( g / mL ) - 1 with a limit of detection as low as 3.55 ag/mL. In specificity analysis, the ADH biosensor demonstrated a higher current value which is 338.64 µA for ADH-spiked in phosphate-buffered saline (PBS) and 557.89 µA for ADH-spiked in human serum in comparison with other biomolecules tested. This experimental evidence shows that the ADH biosensor is ultrasensitive and highly selective towards ADH in PBS buffer and ADH-spiked in human serum.

Flexible Biosensors for the Impedimetric Detection of Protein Targets Using Silk-Conductive Polymer Biocomposites

To expand the applications of flexible biosensors in point-of-care healthcare applications beyond monitoring of biophysical parameters, it is important to devise strategies for the detection of various proteins and biomarkers. Here, we demonstrate a flexible, fully organic, biodegradable, label-free impedimetric biosensor for the critical biomarker, vascular endothelial growth factor (VEGF). This biosensor was constructed by photolithographically patterning a conducting ink consisting of a photoreactive silk sericin coupled with a conducting polymer. These functional electrodes are printed on flexible fibroin substrates that are controllably thick and can be free-standing, or conform to soft surfaces. Detection was accomplished via the antibody to VEGF which was immobilized within the conducting matrix. The results indicated that the developed flexible biosensor was highly sensitive and selective to the target protein, even in challenging biofluids such as human serum. The biosensors themselves are biocompatible and degradable. Through this work, the developed flexible biosensor based on a simple and label-free strategy can find practical applications in the monitoring of wound healing or early disease diagnosis.

An investigation into non-covalent functionalization of a single-walled carbon nanotube and a graphene sheet with protein G:A combined experimental and molecular dynamics study

Investigation of non-covalent interaction of hydrophobic surfaces with the protein G (PrG) is necessary due to their frequent utilization in immunosensors and ELISA. It has been confirmed that surfaces, including carbonous-nanostructures (CNS) could orient proteins for a better activation. Herein, PrG interaction with single-walled carbon nanotube (SWCNT) and graphene (Gra) nanostructures was studied by employing experimental and MD simulation techniques. It is confirmed that the PrG could adequately interact with both SWCNT and Gra and therefore fine dispersion for them was achieved in the media. Results indicated that even though SWCNT was loaded with more content of PrG in comparison with the Gra, the adsorption of the PrG on Gra did not induce significant changes in the IgG tendency. Several orientations of the PrG were adopted in the presence of SWCNT or Gra; however, SWCNT could block the PrG-FcR. Moreover, it was confirmed that SWCNT reduced the α-helical structure content in the PrG. Reduction of α-helical structure of the PrG and improper orientation of the PrG-SWCNT could remarkably decrease the PrG tendency to the Fc of the IgG. Importantly, the Gra could appropriately orient the PrG by both exposing the PrG-FcR and also by blocking the fragment of the PrG that had tendency to interact with Fab in IgG.

Machine Learning Approach to Enhance the Performance of MNP-Labeled Lateral Flow Immunoassay

The use of magnetic nanoparticle (MNP)-labeled immunochromatography test strips (ICTSs) is very important for point-of-care testing (POCT). However, common diagnostic methods cannot accurately analyze the weak magnetic signal from ICTSs, limiting the applications of POCT. In this study, an ultrasensitive multiplex biosensor was designed to overcome the limitations of capturing and normalization of the weak magnetic signal from MNPs on ICTSs. A machine learning model for sandwich assays was constructed and used to classify weakly positive and negative samples, which significantly enhanced the specificity and sensitivity. The potential clinical application was evaluated by detecting 50 human chorionic gonadotropin (HCG) samples and 59 myocardial infarction serum samples. The quantitative range for HCG was 1-1000 mIU mL^-1 and the ideal detection limit was 0.014 mIU mL^-1, which was well below the clinical threshold. Quantitative detection results of multiplex cardiac markers showed good linear correlations with standard values. The proposed multiplex assay can be readily adapted for identifying other biomolecules and also be used in other applications such as environmental monitoring, food analysis, and national security.

Carbon Nanomaterial Based Biosensors for Non-Invasive Detection of Cancer and Disease Biomarkers for Clinical Diagnosis

The early diagnosis of diseases, e.g., Parkinson's and Alzheimer's disease, diabetes, and various types of cancer, and monitoring the response of patients to the therapy plays a critical role in clinical treatment; therefore, there is an intensive research for the determination of many clinical analytes. In order to achieve point-of-care sensing in clinical practice, sensitive, selective, cost-effective, simple, reliable, and rapid analytical methods are required. Biosensors have become essential tools in biomarker sensing, in which electrode material and architecture play critical roles in achieving sensitive and stable detection. Carbon nanomaterials in the form of particle/dots, tube/wires, and sheets have recently become indispensable elements of biosensor platforms due to their excellent mechanical, electronic, and optical properties. This review summarizes developments in this lucrative field by presenting major biosensor types and variability of sensor platforms in biomedical applications.

3D-Printed Multidrug-Eluting Stent from Graphene-Nanoplatelet-Doped Biodegradable Polymer Composite

Patients with percutaneous coronary intervention generally receive either bare metal stents or drug-eluting stents to restore the normal blood flow. However, due to the lack of stent production with an individual patient in mind, the same level of effectiveness may not be possible in treating two different clinical scenarios. This study introduces for the first time the feasibility of a patient-specific stenting process constructed from direct 3D segmentation of medical images using direct 3D printing of biodegradable polymer-graphene composite with dual drug incorporation. A biodegradable polymer-carbon composite is prepared doped with graphene nanoplatelets to achieve controlled release of combinatorics as anticoagulation and antirestenosis agents. This study develops a technology prototyped for personalized stenting. An in silico analysis is performed to optimize the stent design for printing and its prediction of sustainability under force exerted by coronary artery or blood flow. A holistic approach covering in silico to in situ-in vivo establishes the structural integrity of the polymer composite, its mechanical properties, drug loading and release control, prototyping, functional activity, safety, and feasibility of placement in coronary artery of swine.

Grain boundaries guided vibration wave propagation in polycrystalline graphene

Propagation of mechanical stransverse wave in polycrystalline graphene sheet.

Use of quantum dot beads-labeled monoclonal antibody to improve the sensitivity of a quantitative and simultaneous immunochromatographic assay for neuron specific enolase and carcinoembryonic antigen

Detection of multiplex tumor markers was of great importance for cancer diagnosis. Immunochromatographic test strip (ICTS) was the most frequently-used point-of-care detection means. Herein, a convenient and fast method for simultaneous quantitative detection of neuron specific enolase (NSE) and carcinoembryonic antigen (CEA) was developed based on ICTS using quantum dot beads (QBs) as marking material. Good monodispersity, high colloidal stability and carboxyl-modified (COOH-) QBs were used. For this method, two test lines were applied to the NC membrane for simultaneous analysis of CEA and NSE respectively. The ideal limit of CEA and NSE detection was 0.0378ng/mL and 0.0426ng/mL with scarcely any cross-reactivity. Moreover, the fluorescent signal intensity of the nitrocellulose membrane could be easily read out in the cooperation of the "Handing" system without professional operators. The possible clinical utilization of this platform was demonstrated by detecting 100 clinic human serums. The result showed that the platform had sensitivity of 99% and 97% for CEA and NSE, while the specificity was 97% and 100% respectively. Our results indicated that the QBs based ICTS not only owning the ability of sensitive and specific simultaneous detection of CEA and NSE, but also showing the potential in developing this ICTS into a routine part of early lung cancer diagnosis.

Applications and toxicity of graphene family nanomaterials and their composites

Graphene has attracted much attention of scientific community due to its enormous potential in different fields, including medical sciences, agriculture, food safety, cancer research, and tissue engineering. The potential for widespread human exposure raises safety concerns about graphene and its derivatives, referred to as graphene family nanomaterials (GFNs). Due to their unique chemical and physical properties, graphene and its derivatives have found important places in their respective application fields, yet they are being found to have cytotoxic and genotoxic effects too. Since the discovery of graphene, a number of researches are being conducted to find out the toxic potential of GFNs to different cell and animal models, finding their suitability for being used in new and varied innovative fields. This paper presents a systematic review of the research done on GFNs and gives an insight into the mode and action of these nanosized moieties. The paper also emphasizes on the recent and up-to-date developments in research on GFNs and their nanocomposites for their toxic effects.

Ultra-large suspended graphene as a highly elastic membrane for capacitive pressure sensors

In this work, we fabricate ultra-large suspended graphene membranes, where stacks of a few layers of graphene could be suspended over a circular hole with a diameter of up to 1.5 mm, with a diameter to thickness aspect ratio of 3 × 10(5), which is the record for free-standing graphene membranes. The process is based on large crystalline graphene (∼55 μm) obtained using a chemical vapor deposition (CVD) method, followed by a gradual solvent replacement technique. Combining a hydrogen bubbling transfer approach with thermal annealing to reduce polymer residue results in an extremely clean surface, where the ultra-large suspended graphene retains the intrinsic features of graphene, including phonon response and an enhanced carrier mobility (200% higher than that of graphene on a substrate). The highly elastic mechanical properties of the graphene membrane are demonstrated, and the Q-factor under 2 MHz stimulation is measured to be 200-300. A graphene-based capacitive pressure sensor is fabricated, where it shows a linear response and a high sensitivity of 15.15 aF Pa(-1), which is 770% higher than that of frequently used silicon-based membranes. The reported approach is universal, which could be employed to fabricate other suspended 2D materials with macro-scale sizes on versatile support substrates, such as arrays of Si nano-pillars and deep trenches.

Graphene: The Missing Piece for Cancer Diagnosis?

This paper reviews recent advances in graphene-based biosensors development in order to obtain smaller and more portable devices with better performance for earlier cancer detection. In fact, the potential of Graphene for sensitive detection and chemical/biological free-label applications results from its exceptional physicochemical properties such as high electrical and thermal conductivity, aspect-ratio, optical transparency and remarkable mechanical and chemical stability. Herein we start by providing a general overview of the types of graphene and its derivatives, briefly describing the synthesis procedure and main properties. It follows the reference to different routes to engineer the graphene surface for sensing applications with organic biomolecules and nanoparticles for the development of advanced biosensing platforms able to detect/quantify the characteristic cancer biomolecules in biological fluids or overexpressed on cancerous cells surface with elevated sensitivity, selectivity and stability. We then describe the application of graphene in optical imaging methods such as photoluminescence and Raman imaging, electrochemical sensors for enzymatic biosensing, DNA sensing, and immunosensing. The bioquantification of cancer biomarkers and cells is finally discussed, particularly electrochemical methods such as voltammetry and amperometry which are generally adopted transducing techniques for the development of graphene based sensors for biosensing due to their simplicity, high sensitivity and low-cost. To close, we discuss the major challenges that graphene based biosensors must overcome in order to reach the necessary standards for the early detection of cancer biomarkers by providing reliable information about the patient disease stage.

Application of three-dimensional flower-like nanomaterials in the fabrication of sandwich-type electrochemical immunosensors

A novel and ultrasensitive sandwich-type electrochemical immunosensor was developed for the quantitative detection of carcinoembryonic antigen (CEA) in this work.