Laser-scribed Graphene Research Articles

Laser-Induced Graphene for Advanced Sensing: Comprehensive Review of Applications.

Laser-induced graphene (LIG) and Laser-scribed graphene (LSG) are both advanced materials with significant potential in various applications, particularly in the field of sustainable sensors. The practical uses of LIG (LSG), which include gas detection, biological process monitoring, strain assessment, and environmental variable tracking, are thoroughly examined in this review paper. Its tunable characteristics distinguish LIG (LSG), which is developed from accurate laser beam modulation on polymeric substrates, and they are essential in advancing sensing technologies in many applications. The recent advances in LIG (LSG) applications include energy storage, biosensing, and electronics by steadily advancing efficiency and versatility. The remarkable flexibility of LIG (LSG) and its transformative potential in regard to sensor manufacturing and utilization are highlighted in this manuscript. Moreover, it thoroughly examines the various fabrication methods used in LIG (LSG) production, highlighting precision and adaptability. This review navigates the difficulties that are encountered in regard to implementing LIG sensors and looks ahead to future developments that will propel the industry forward. This paper provides a comprehensive summary of the latest research in LIG (LSG) and elucidates this innovative material's advanced and sustainable elements.

Facile and scalable fabrication of flexible microsupercapacitor based on boron modified 2D/2D 1 T MoS2/MXene hybrids

Micro-supercapacitors (MSCs) with outstanding flexibility and electrochemical performance are critical for portable and miniaturized electronics. This study utilizes the potential utilization of Boron-modified MoS2/MXene heterostructure for fabricating highly efficient and durable microsupercapacitors. The Boron incorporation and hybrid formation significantly enhance the electrochemical performance of 1 T MoS2 and MXene (Ti3C2Tx) by activating their basal plane. The boron modified MoS2/Ti3C2Tx(B-1 T MoS2/Ti3C2Tx_) demonstrates excellent energy storage performance with a capacitance of around 420 Fg−1 in two-electrode system. Laser scribed graphene (LSG), chosen for its superior wettability, serves as the current collector facilitating the development of these MSC based on B-1 T MoS2/Ti3C2Tx. The resulting MSC demonstrates a high areal capacitance of nearly 72.31 mF/cm2 and excellent stability over 10,000 cycles. Density functional theory (DFT) simulations support these findings, indicating that hybridization with Ti3C2Tx and B substitution enhances the conductivity of the 1 T-MoS2 system. The quantum capacitance of B-substituted hybrid system surpasses that of the pristine material, validating the experimental observations of enhanced charge storage performance.

Ultrafast Sodium–Ion Batteries Based on Vanadium Oxide and Laser-Scribed Graphene Electrodes

Ultrafast Sodium–Ion Batteries Based on Vanadium Oxide and Laser-Scribed Graphene Electrodes

A wearable nanozyme–enzyme electrochemical biosensor for sweat lactate monitoring

In this study, we developed a wearable nanozyme–enzyme electrochemical biosensor that enablies sweat lactate monitoring. The biosensor comprises a flexible electrode system prepared on a polyimide (PI) film and the Janus textile for unidirectional sweat transport. We obtained favorable electrochemical activities for hydrogen peroxide reduction by modifying the laser-scribed graphene (LSG) electrode with cerium dioxide (CeO2)–molybdenum disulphide (MoS2) nanozyme and gold nanoparticles (AuNPs). By further immobilisation of lactate oxidase (LOx), the proposed biosensor achieves chronoamperometric lactate detection in artificial sweat within a range of 0.1–50.0 mM, a high sensitivity of 25.58 μA mM−1cm−2 and a limit of detection (LoD) down to 0.135 mM, which fully meets the requirements of clinical diagnostics. We demonstrated accurate lactate measurements in spiked artificial sweat, which is consistent with standard ELISA results. To monitor the sweat produced by volunteers while exercising, we conducted on-body tests, showcasing the wearable biosensor's ability to provide clinical sweat lactate diagnosis for medical treatment and sports management.

A MOFs‐Derived Hydroxyl‐Functionalized Hybrid Nanoporous Carbon Incorporated Laser‐Scribed Graphene‐Based Multimodal Skin Patch for Perspiration Analysis and Electrocardiogram Monitoring

AbstractAlthough metal‐organic framework (MOF)‐derived nanoporous C (NPC) materials offer several advantages for electrochemical sensor applications, surface functionalization and porosity tuning can affect sensor performance. This study presents the development of a skin patch for perspiration and electrocardiogram (ECG) monitoring, leveraging the unique properties of MOF‐on‐MOF‐derived surface‐functionalized hybrid nanoporous C (f‐HNPC) incorporated into laser‐scribed graphene (LSG). Hydroxyl (OH) group‐functionalized NPC, achieved through KOH activation, facilitates electron transport at the electrode–electrolyte interface. This enhances the electrochemical activity, thereby improving sensor sensitivity and expanding the detection range. The integration of f‐HNPC provides enhanced surface area and electrochemical properties, enabling sensitive and selective detection of sweat biomarkers, including glucose (103 µA mM−1 cm−2) and uric acid (184 µA mM−1 cm−2) along with an ultra‐wide glucose detection range (up to 41.5 mM). Moreover, the incorporation of LSG ensures excellent mechanical flexibility, facilitating conformal contact with the skin for reliable signal acquisition. The proposed skin patch demonstrates promising performance in real‐time perspiration analysis and ECG monitoring with a signal‐to‐noise ratio of 23.63 dB, along with high stability and long‐term durability. The synergistic combination of f‐HNPC and LSG shows great potential for developing advanced wearable biosensing platforms for personalized healthcare applications.

Electrochemically deposited Au nano-island on laser-scribed graphene substrates as EC-SERS biochips for uremic toxins detection

BackgroundChronic kidney disease (CKD) leads to uremic toxin buildup, requiring early detection for better management. Existing methods lack sensitivity, speed, or affordability for point-of-care diagnosis. This work addresses this by creating a novel sensor for rapid, sensitive uremic toxin detection. MethodsThe sensor leverages the combined effects of surface-enhanced Raman scattering (SERS) and electrochemistry (EC) for superior detection. The LIG substrate provides a stable platform for AuNPs, facilitating interaction with target molecules. Additionally, electrochemical deposition optimizes the sensor's sensitivity by amplifying the local electromagnetic field around AuNPs and offering specific binding sites for uremic toxins. Significant findingsThe developed sensor demonstrates exceptional performance in detecting uremic toxins. It achieves remarkably low detection limits (10-3 M for creatinine/uric acid, 10-4 M for urea) and offers distinct, concentration-dependent responses for different toxins in cyclic voltammetry (CV) measurements. Furthermore, characteristic oxidation peaks at specific potentials allow for direct identification and quantification of the toxins. These findings highlight the immense potential of this cost-effective and scalable sensor for point-of-care diagnostics and remote monitoring of kidney function. This advancement can significantly improve patient care by facilitating early detection of kidney problems and enabling timely intervention.

Hybrid microsupercapacitors based on Ti3C2Tx MXene and covalent organic frameworks

The growing demand for emerging electronic applications, including energy storage, sensors, and portable devices, has created a pressing need to develop miniaturized flexible energy storage components with convenient device architecture. Here, we report an in-plane hybrid micro-supercapacitor made of covalent organic frameworks and Ti3C2Tx MXene as positive and negative electrodes, respectively. The devices utilize three-dimensional laser-scribed graphene (LSG) as a current collector for both electrodes using a CO2-laser-based technique due to its good resolution for in-plane device fabrication, and high porosity of LSG that can facilitate better rate performance. The constructed hybrid supercapacitor has a maximum areal capacitance of 131.46 mF/cm2 and a voltage window of 1.2 V. The findings provide a new strategy to fabricate a hybrid supercapacitor for self-powered device applications at the microscale.

Gold-modified laser-scribed lettuce-like graphene electrodes for ultrasensitive detection of bioactive molecules

Gold-modified laser-scribed lettuce-like graphene electrodes for ultrasensitive detection of bioactive molecules

Laser-Scribed Graphene for Human Health Monitoring: From Biophysical Sensing to Biochemical Sensing.

Laser-scribed graphene (LSG), a classic three-dimensional porous carbon nanomaterial, is directly fabricated by laser irradiation of substrate materials. Benefiting from its excellent electrical and mechanical properties, along with flexible and simple preparation process, LSG has played a significant role in the field of flexible sensors. This review provides an overview of the critical factors in fabrication, and methods for enhancing the functionality of LSG. It also highlights progress and trends in LSG-based sensors for monitoring physiological indicators, with an emphasis on device fabrication, signal transduction, and sensing characteristics. Finally, we offer insights into the current challenges and future prospects of LSG-based sensors for health monitoring and disease diagnosis.

Micromesh reinforced strain sensor with high stretchability and stability for full‐range and periodic human motions monitoring

AbstractThe development of strain sensors with high stretchability and stability is an inevitable requirement for achieving full‐range and long‐term use of wearable electronic devices. Herein, a resistive micromesh reinforced strain sensor (MRSS) with high stretchability and stability is prepared, consisting of a laser‐scribed graphene (LSG) layer and two styrene‐block‐poly(ethylene‐ran‐butylene)‐block‐poly‐styrene micromesh layers embedded in Ecoflex. The micromesh reinforced structure endows the MRSS with combined characteristics of a high stretchability (120%), excellent stability (with a repetition error of 0.8% after 11 000 cycles), and outstanding sensitivity (gauge factor up to 2692 beyond 100%). Impressively, the MRSS can still be used continauously within the working range without damage, even if stretched to 300%. Furthermore, compared with different structure sensors, the mechanism of the MRSS with high stretchability and stability is elucidated. What's more, a multilayer finite element model, based on the layered structure of the LSG and the morphology of the cracks, is proposed to investigate the strain sensing behavior and failure mechanism of the MRSS. Finally, due to the outstanding performance, the MRSS not only performes well in monitoring full‐range human motions, but also achieves intelligent recognitions of various respiratory activities and gestures assisted by neural network algorithms (the accuracy up to 94.29% and 100%, respectively). This work provides a new approach for designing high‐performance resistive strain sensors and shows great potential in full‐range and long‐term intelligent health management and human–machine interactions applications.image

Reprecipitation: A Rapid Synthesis of Micro-Sized Silicon-Graphene Composites for Long-lasting Lithium-Ion Batteries.

Silicon microparticles (SiMPs) have gained significant attention as a lithium-ion battery anode material due to their 10 times higher theoretical capacity compared to conventional graphite anodes as well as their much lower production cost than silicon nanoparticles (SiNPs). However, SiMPs have suffered from poorer cycle life relative to SiNPs because their larger size makes them more susceptible to volume changes during charging and discharging. Creating a wrapping structure in which SiMPs are enveloped by carbon layers has proven to be an effective strategy to significantly improve the cycling performance of SiMPs. However, the synthesis processes are complex and time-/energy-consuming and therefore not scalable. In this study, a wrapping structure is created by using a simple, rapid, and scalable "modified reprecipitation method". Graphene oxide (GO) and SiMP dispersion in tetrahydrofuran is injected into n-hexane, in which GO and SiMP by themselves cannot disperse. GO and SiMP therefore aggregate and precipitate immediately after injection to form a wrapping structure. The resulting SiMP/GO film is laser scribed to reduce GO to a laser-scribed graphene (LSG). Simultaneously, SiOx and SiC protection layers form on the SiMPs through the laser process, which alleviates severe volume change. Owing to these desirable characteristics, the modified reprecipitation method successfully doubles the cycle life of SiMP/graphene composites compared to the simple physically mixing method (50.2% vs. 24.0% retention at the 100th cycle). The modified reprecipitation method opens a new synthetic strategy for SiMP/carbon composites.

Activated and shorter Laser-Scribed graphene Electrodes: Excellent electrochemical signal amplification for detecting biomarkers

Laser-scribed graphene electrodes (LSGEs) are emerging as powerful transducers in electroanalysis. Surface structure and electrode geometry are the two key properties that heavily influence the characteristics of the resulting biosensors. In this work, we have investigated the sensing abilities of the LSGEs at various electrochemical activation procedures and electrode geometry conditions. We found that electrochemically activated LSGEs with shorter electrode connection lengths outperform corresponding non-activated LSGEs with longer electrode connection lengths. The effects of different pH conditions, supporting electrolytes, polarization potentials, and activation time were studied. X-ray photoelectron spectroscopy, Raman spectroscopy, and voltammetry techniques were used to examine the in-situ formation of porosity, introduction of surface oxygen functionalities, role of defect densities, and electrochemically accessible area. Dopamine is used as a model to study the sensing capabilities of the electrodes. Activated LSGE offered a 5.4-fold enhanced detection limit for dopamine compared to longer and non-activated LSGE. Practicality of the method is validated in human serum and urine samples. In addition, the sensor was demonstrated in monitoring in-situ dopamine released by neuroblastoma SH-SY5Y cells. Additionally, the enhanced sensing performance of the activated LSGEs are also tested by sensing uric acid and paracetamol. Electrochemically activated, shorter LSGEs hold great potential in various electrochemical applications.

Dual-responsive 3D DNA nanomachines cascaded hybridization chain reactions for novel self-powered flexible microRNA-detecting platform

The microRNA-21 is closely related to chromatin remodeling and epigenetic regulation. In this work, an efficient double-response 3D DNA nanomachine (DRDN) was assembled by co-immobilizing two different lengths of hairpin DNA on the surface of gold nanoparticles (AuNPs) to capture microRNA-21 (miRNA-21), recycle miRNA-21, and trigger hybridization chain reactions (HCR). This work reports the fabrication of a laser-scribed graphene (LSG) electrode with excellent flexibility and electrical conductivity by laser-scribing commercial polyimide films (PI). The as-proposed self-powered biosensing platform presents significantly increased instantaneous current to in real-time monitor miRNA-21 by a capacitor. The biosensing platform exhibited highly sensitive detection of miRNA-21 with a detection limit of 0.142 fM in the range of 0.5 fM to 1 × 104 fM, and demonstrated high efficiency in the analysis of the tumor markers.

One‐Step Synthesis of Copper Single‐Atom Nanozymes for Electrochemical Sensing Applications

Single‐atom nanozymes (SANs) combine the natural enzymatic properties of nanomaterials with the atomic distribution of metallic sites over a suitable support. Unfortunately, their synthesis is complicated by some key factors, like poor metallic loading, aggregation, time consumption, and low yield. Herein, copper SANs, with a surface metal loading (1.47% ± 0.16%) are synthesized, through a green, facile, minimal solution processing, single‐step procedure, using a CO2 laser to promote the anchoring of the metallic precursor while simultaneously generating the laser‐scribed graphene (LSG) support out of a polyimide sheet. The presence of the atomic Cu on the LSG surface is verified using high‐angle‐annular dark‐field–scanning transmission electron microscopy and X‐ray photoelectron spectroscopy. To explore the advantages incurred by the incorporation of Cu SANs on LSG, the material is used as a working electrode on an electrochemical sensor for the amperometric detection of H2O2, achieving a detection limit of 2.40 μM. The findings suggest that CuSANs can confer enhanced sensitivity to H2O2, which is essential for oxidative stress assessment, reaching values up to 130.0 μA mM−1 cm−2.

Porous Laser-Scribed Graphene Electrodes Modified with Zwitterionic Moieties: A Strategy for Antibiofouling and Low-Impedance Interfaces.

Laser-scribed graphene electrodes (LSGEs) are promising platforms for the development of electrochemical biosensors for point-of-care settings and continuous monitoring and wearable applications. However, the frequent occurrence of biofouling drastically reduces the sensitivity and selectivity of these devices, hampering their sensing performance. Herein, we describe a versatile, low-impedance, and robust antibiofouling interface based on sulfobetaine-zwitterionic moieties. The interface induces the formation of a hydration layer and exerts electrostatic repulsion, protecting the electrode surface from the nonspecific adsorption of various biofouling agents. We demonstrate through electrochemical and microscopy techniques that the modified electrode exhibits outstanding antifouling properties, preserving more than 90% of the original signal after 24 h of exposure to bovine serum albumin protein, HeLa cells, and Escherichia coli bacteria. The promising performance of this antifouling strategy suggests that it is a viable option for prolonging the lifetime of LSGEs-based sensors when operating on complex biological systems.

Simultaneous detection of SARS-CoV-2 S1 protein by using flexible electrochemical and Raman enhancing biochip

Flexible laser-scribed graphene (LSG) substrates with gold nanoislands have been developed as biochips for in situ electrochemical (EC) and surface-enhanced Raman scattering (SERS) biodetection (biomolecules and viral proteins). A flexible biochip was fabricated using CO2 laser engraving polyimide (PI) films to form a 3D porous graphene-like nanostructure. Gold nanoislands were deposited on the LSG substrates to enhance the intensity of the Raman signals. Moreover, the addition of auxiliary and reference electrodes induced a dual-function EC-SERS biochip with significantly enhanced detection sensitivity. The biochip could selectively and easily capture SARS-CoV-2 S1 protein through the SARS-CoV-2 S1 antibody immobilized on EC-SERS substrates using 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The grafted antibody specifically bound to SARS-CoV-2, resulting in a significant increase in the SERS signal of the target analyte. The limit of detection (LOD) of the SARS-CoV-2 S1 protein was 5 and 100 ng/mL by using EC and SERS detection, respectively. Although the LOD of the SARS-CoV-2 S1 protein detected using SERS is only 100 ng/mL, it can provide fingerprint information for identification. To improve the LOD, EC detection was integrated with SERS detection. The three-electrode detection chip enables the simultaneous detection of SERS and EC signals, which provides complementary information for target identification. The dual-functional detection technology demonstrated in this study has great potential for biomedical applications, such as the rapid and sensitive detection of SARS-CoV-2.

Graphene and metal-organic framework hybrids for high-performance sensors for lung cancer biomarker detection supported by machine learning augmentation.

Conventional diagnostic methods for lung cancer, based on breath analysis using gas chromatography and mass spectrometry, have limitations for fast screening due to their limited availability, operational complexity, and high cost. As potential replacement, among several low-cost and portable methods, chemoresistive sensors for the detection of volatile organic compounds (VOCs) that represent biomarkers of lung cancer were explored as promising solutions, which unfortunately still face challenges. To address the key problems of these sensors, such as low sensitivity, high response time, and poor selectivity, this study presents the design of new chemoresistive sensors based on hybridised porous zeolitic imidazolate (ZIF-8) based metal-organic frameworks (MOFs) and laser-scribed graphene (LSG) structures, inspired by the architecture of the human lung. The sensing performance of the fabricated ZIF-8@LSG hybrid sensors was characterised using four dominant VOC biomarkers, including acetone, ethanol, methanol, and formaldehyde, which are identified as metabolomic signatures in lung cancer patients' exhaled breath. The results using simulated breath samples showed that the sensors exhibited excellent performance for a set of these biomarkers, including fast response (2-3 seconds), a wide detection range (0.8 ppm to 50 ppm), a low detection limit (0.8 ppm), and high selectivity, all obtained at room temperature. Intelligent machine learning (ML) recognition using the multilayer perceptron (MLP)-based classification algorithm was further employed to enhance the capability of these sensors, achieving an exceptional accuracy (approximately 96.5%) for the four targeted VOCs over the tested range (0.8-10 ppm). The developed hybridised nanomaterials, combined with the ML methodology, showcase robust identification of lung cancer biomarkers in simulated breath samples containing multiple biomarkers and a promising solution for their further improvements toward practical applications.

A Portable and Disposable Electrochemical Sensor Utilizing Laser-Scribed Graphene for Rapid SARS-CoV-2 Detection.

The COVID-19 pandemic caused by the virus SARS-CoV-2 was the greatest global threat to human health in the last three years. The most widely used methodologies for the diagnosis of COVID-19 are quantitative reverse transcription polymerase chain reaction (RT-qPCR) and rapid antigen tests (RATs). PCR is time-consuming and requires specialized instrumentation operated by skilled personnel. In contrast, RATs can be used in-home or at point-of-care but are less sensitive, leading to a higher rate of false negative results. In this work, we describe the development of a disposable, electrochemical, and laser-scribed graphene-based biosensor strips for COVID-19 detection that exploits a split-ester bond ligase system (termed 'EsterLigase') for immobilization of a virus-specific nanobody to maintain the out-of-plane orientation of the probe to ensure the efficacy of the probe-target recognition process. An anti-spike VHH E nanobody, genetically fused with the EsterLigase domain, was used as the specific probe for the spike receptor-binding domain (SP-RBD) protein as the target. The recognition between the two was measured by the change in the charge transfer resistance determined by fitting the electrochemical impedance spectroscopy (EIS) spectra. The developed LSG-based biosensor achieved a linear detection range for the SP-RBD from 150 pM to 15 nM with a sensitivity of 0.0866 [log(M)]-1 and a limit of detection (LOD) of 7.68 pM.

Anti-biofouling laser-scribed graphene electrochemical sensor for reliable detection of uric acid in human saliva

The direct detection of uric acid (UA) in unprocessed raw saliva by electrochemical sensors is usually a challenge because of the strong biofouling effect of some mucoproteins. Here, a disposable and anti-biofouling graphene electrochemical sensor for the detection of UA in human saliva is reported. The sensor was fabricated by the modification of a composite of BSA and Tween-20 (BSAT) on laser-induced graphene (LIG) electrodes via drop casting. This modification method produces an ultrathin BSAT coating on the sidewall of porous LIG sheets via possible hydrophobic interactions, which apparently improves the hydrophilicity and anti-biofouling ability of the LIG-based sensor. The structural and electrochemical properties of the BSAT coating were investigated by various techniques, and electrode kinetics-dependent electrochemical behaviors of various electroactive probes were observed. Under optimal conditions, the UA sensor possesses a calibration range of 20.0 ∼ 1000 μM and a detection limit of 2.1 μM (S/N = 3), which was successfully applied to the detection of UA in 5-fold diluted human raw saliva under different physiological conditions.

Electric field-stimulated Raman scattering enhancing biochips fabricated by Au nano-islands deposited on laser-scribed 3D graphene for uremic toxins detection

BackgroundThe detection of uremic toxins is important for early-stage diagnosis of chronic kidney disease. However, Raman spectroscopy is shortcoming of the sensitivity for detecting the trace analytes. The electric field-induced chemical surface-enhanced Raman scattering (SERS) enhancement (EC-SERS) detection is great way to solve and investigates uremic toxins. MethodsIn this work, various thickness (5–25 nm) of Au nano-islands were deposited on the 3D laser-scribed graphene (LSG) substrate for increasing the sensitivity and reproducibility of SERS detection. Particularly, applying the electric-field stimulus in Au-LSG SERS substrate allows to further amplify the SERS signals, and measure the EC-SERS signals of biomolecules. Significant findingsThe results show that 20 nm of Au nano-islands coated on LSG substrate obtains the highest SERS enhancement effects, and successfully detects the dye molecules (rhodamine 6G, R6G) and uremic toxins (urea and creatinine). The EC-SERS signals of R6G would enhance 17 times at the potential of −1.3 V, compared to SERS signals without applying an electric field. Moreover, the urea also displays 4 times higher at the potential of −0.2 V. The detecting molecules could be selected to enhance SERS signals by different voltages, showing the capability of selectively detecting biomolecules, which can solve the problem of complex sample pretreatment.