Nanomaterial‐Based Electrochemical Sensors: Mechanism, Preparation, and Application in Biomedicine

Portable smartphone-assisted amperometric immunosensor based on CoCe-layered double hydroxide for rapidly immunosensing erythromycin

Herein, we have manufactured a newly designed bifunctional impedimetric and amperometric immunosensor for rapidly detecting erythromycin (ERY) in complicated environments and food stuffs. For this, bimetallic cobalt/cerium-layered double hydroxide nanosheets (CoCe-LDH NSs), which was derived from Co-based zeolite imidazole framework via the structure conversion, was simultaneously utilized as the bioplatform for anchoring the ERY-targeted antibody and for modifying the gold and screen printed electrode. Basic characterizations revealed that CoCe-LDH NSs was composed of mixed metal valences, enrich redox, and abundant oxygen vacancies, facilitating the adhesion on the electrode, the antibody adsorption, and the electron transfers. The manufactured impedimetric and amperometric immunosensor based on CoCe-LDH has showed the comparable sensing performance, having a wide linear detection range from 1.0 fg mL-1 to 1.0 ng mL-1 with the ultralow detection limit toward ERY. Also, the portable, visualized, and efficient analysis of ERY was then attained at the smartphone-assisted CoCe-LDH-based SPE.

Surface-engineered vertically-aligned ZnO nanorod for sensitive non-enzymatic electrochemical monitoring of cholesterol

Developing highly sensitive and selective non-enzymatic electrochemical biosensors for disease biomarker detection has become challenging in healthcare applications. However, advances in material science are opening new avenues for creating more dependable biosensing technologies. In this context, the present work introduces a novel approach by engineering a hybrid structure of zinc oxide nanorod (ZnO NR) modified with iron oxide nanoparticle (Fe2O3 NP) on an FTO electrode. This Fe2O3 NP-ZnO NR hybrid material functions as a nanozyme, facilitating the catalysis of cholesterol and enabling the direct transfer of electrons to the fluorine-doped tin oxide (FTO) electrode, limiting the need for costly and traditional enzymes in the detection process. This innovative non-enzymatic cholesterol biosensor showcases remarkable sensitivity, registering at 642.8 μA/mMcm2 within a linear response range of up to 9.0 mM. It also exhibits a low detection limit (LOD) of ∼12.4 μM, ensuring its capability to detect minimal concentrations of cholesterol accurately. Moreover, the developed biosensor displays exceptional selectivity by effectively distinguishing cholesterol molecules from other interfering biological species, while exhibiting outstanding stability and reproducibility. Our findings indicate that the Fe2O3 NP-ZnO NR hybrid nanostructure on the FTO electrode holds promise for enhancing biosensor stability. Furthermore, the present device fabrication platform offers versatility, as it can be adapted with various enzymes or modified with different metal oxides, potentially broadening its applicability in a wide range of biomarkers detection.

Preparation of a Carbon paste electrode with Active materials for the detection of Tetracycline

The Electrochemical sensor based on carbon-clay paste electrode (CCPE) was constructed for sensitive determination of Tetracycline (Tc). The mineralogical composition, morphology, structure and performance of CCPE were characterized using X-ray diffraction powder, Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Cyclic Voltammetry analysis. The CCPE is constituted of two types of clay having the ratio 1/1 and 2/1 characteristic of kaolinite and montmorillonite clay respectively. Its porous structure is ascribed to the presence of graphite. The CCPE exhibited a good electrocatalytic activity towards the oxidation of Tc. The electrochemical kinetics and mechanism of Tc were proposed, showing that Tc electrocatalytic oxidation reaction was controlled by diffusion process and took place in three steps. A low concentration of Tc was detected by amperometry with the linear ranges of 0.5μM-0.8 μM (R2 = 0.98), the sensitivity was 8.01 μA/μM.cm2, the limit of detection and quantification were 5.16x10-3μM(S/N = 3) and 1.72x10-2μM respectively. Thus, the proposed electrode provides a promising and prospective CCPE sensing platform for the detection of Tc in the environment.

Sensing Utilities of Cesium Lead Halide Perovskites and Composites: A Comprehensive Review

Recently, the utilization of metal halide perovskites in sensing and their application in environmental studies have reached a new height. Among the different metal halide perovskites, cesium lead halide perovskites (CsPbX3; X = Cl, Br, and I) and composites have attracted great interest in sensing applications owing to their exceptional optoelectronic properties. Most CsPbX3 nanostructures and composites possess great structural stability, luminescence, and electrical properties for developing distinct optical and photonic devices. When exposed to light, heat, and water, CsPbX3 and composites can display stable sensing utilities. Many CsPbX3 and composites have been reported as probes in the detection of diverse analytes, such as metal ions, anions, important chemical species, humidity, temperature, radiation photodetection, and so forth. So far, the sensing studies of metal halide perovskites covering all metallic and organic-inorganic perovskites have already been reviewed in many studies. Nevertheless, a detailed review of the sensing utilities of CsPbX3 and composites could be helpful for researchers who are looking for innovative designs using these nanomaterials. Herein, we deliver a thorough review of the sensing utilities of CsPbX3 and composites, in the quantitation of metal ions, anions, chemicals, explosives, bioanalytes, pesticides, fungicides, cellular imaging, volatile organic compounds (VOCs), toxic gases, humidity, temperature, radiation, and photodetection. Furthermore, this review also covers the synthetic pathways, design requirements, advantages, limitations, and future directions for this material.

Electrochemical Monitoring in Anticoagulation Therapy

The process of blood coagulation, wherein circulating blood transforms into a clot in response to an internal or external injury, is a critical physiological mechanism. Monitoring this coagulation process is vital to ensure that blood clotting neither occurs too rapidly nor too slowly. Anticoagulants, a category of medications designed to prevent and treat blood clots, require meticulous monitoring to optimise dosage, enhance clinical outcomes, and minimise adverse effects. This review article delves into the various stages of blood coagulation, explores commonly used anticoagulants and their targets within the coagulation enzyme system, and emphasises the electrochemical methods employed in anticoagulant testing. Electrochemical sensors for anticoagulant monitoring are categorised into two types. The first type focuses on assays measuring thrombin activity via electrochemical techniques. The second type involves modified electrode surfaces that either directly measure the redox behaviours of anticoagulants or monitor the responses of standard redox probes in the presence of these drugs. This review comprehensively lists different electrode compositions and their detection and quantification limits. Additionally, it discusses the potential of employing a universal calibration plot to replace individual drug-specific calibrations. The presented insights are anticipated to significantly contribute to the sensor community's efforts in this field.

Biopolymer-protected graphene-Fe3O4 nanocomposite based wearable microneedle sensor: toward real-time continuous monitoring of dopamine

Neurological disorders can occur in the human body as a result of nano-level variations in the neurotransmitter levels. Patients affected by neuropsychiatric disorders, that are chronic require continuous monitoring of these neurotransmitter levels for effective disease management. The current work focus on developing a highly sensitive and personalized sensor for continuous monitoring of dopamine. Here we propose a wearable microneedle-based electrochemical sensor, to continuously monitor dopamine in interstitial fluid (ISF). A chitosan-protected hybrid nanomaterial Fe3O4-GO composite has been used as a chemical recognition element protected by Nafion antifouling coating layer. The morphological and physiochemical characterizations of the nanocomposite were carried out with XRD, XPS, FESEM, EDAX and FT-IR. The principle of the developed sensor relies on orthogonal detection of dopamine with square wave voltammetry and chronoamperometric techniques. The microneedle sensor array exhibited an attractive analytical performance toward detecting dopamine in phosphate buffer and artificial ISF. The limit of detection (LOD) of the developed sensor was observed to be low, 90 nM in square wave voltammetry and 0.6 μM in chronoamperometric analysis. The practical applicability of the microneedle sensor array has been demonstrated on a skin-mimicking phantom gel model. The microneedle sensor also exhibited good long-term storage stability, reproducibility, and sensitivity. All of these promising results suggest that the proposed microneedle sensor array could be reliable for the continuous monitoring of dopamine.

Pain-Free Alpha-Synuclein Detection by Low-Cost Hierarchical Nanowire Based Electrode

Analytical methods for the early detection of the neurodegenerative biomarker for Parkinson's disease (PD), α-synuclein, are time-consuming and invasive, and require skilled personnel and sophisticated and expensive equipment. Thus, a pain-free, prompt and simple α-synuclein biosensor for detection in plasma is highly demanded. In this paper, an α-synuclein electrochemical biosensor based on hierarchical polyglutamic acid/ZnO nanowires decorated by gold nanoparticles, assembled as nanostars (NSs), for the determination of α-synuclein in human plasma is proposed. ZnO NSs were prepared by chemical bath deposition (CBD) and decorated with electrodeposited Au nanoparticles (Au NPs). Then, electro-polymerized glutamic acid was grown and functionalized with anti-α-synuclein. A synergistic enhancement of electrode sensitivity was observed when Au NPs were embedded into ZnO NSs. The analytical performance of the biosensor was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), using the Fe(II)(CN)64-/Fe(III)(CN)63- probe. The charge transfer resistance after α-synuclein recognition was found to be linear, with a concentration in the range of 0.5 pg·mL-1 to 10 pg·mL-1, a limit of detection of 0.08 pg·mL-1, and good reproducibility (5% variation) and stability (90%). The biosensor was also shown to reliably discriminate between healthy plasma and PD plasma. These results suggest that the proposed biosensor provides a rapid, quantitative and high-sensitivity result of the α-synuclein content in plasma, and represents a feasible tool capable of accelerating the early and non-invasive identification of Parkinson's disease.

Reduction of alcohol-induced mitochondrial damage with ginsenoside Rg1 studied by atomic force microscopy

The quantification of mitochondrial morphology and mechanical properties is useful for the diagnosis and treatment of mitochondrial and alcoholic liver disease. In this study, the effects of ginsenoside Rg1 (G-Rg1) on the morphology and mechanical properties of mitochondria that had suffered alcohol-induced damage were investigated under near-physiological conditions. Additionally, the morphological and mechanical properties of mitochondria were quantified through atomic force microscopy. Atomic force microscopy revealed that alcohol-induced significant morphological changes in mitochondria. Compared with that of the mitochondria of normal hepatocytes, the average surface area of the damaged mitochondria was found to have increased significantly under the influence of alcohol. Furthermore, the mitochondrial area tended to be normal under the action of G-Rg1, whilst other parameters (length, width and perimeter) were significantly different from those of the mitochondria with the alcohol-induced damage. Simultaneously, alcohol significantly reduced the adhesion and elastic modulus of mitochondria, whilst the adhesion and elastic modulus of mitochondria in the G-Rg1 treatment group were closer to the values of normal mitochondria. This study overall showed that G-Rg1 could effectively alleviate the swelling and anomalous mechanical properties of mitochondria induced by alcohol.

Robust Biosensor Based on Carbon Nanotubes/Protein Hybrid Electrolyte Gated Transistors

Semiconducting single walled carbon nanotubes (SWCNTs) are promising materials for biosensing applications with electrolyte-gated transistors (EGT). However, to be employed in EGT devices, SWCNTs often require lengthy solution-processing fabrication techniques. Here, we introduce a simple solution-based method that allows fabricating EGT devices from stable dispersions of SWCNTs/bovine serum albumin (BSA) hybrids in water. The dispersion is then deposited on a substrate allowing the formation of a SWCNTs random network as the semiconducting channel. We demonstrate that this methodology allows the fabrication of EGT devices with electric performances that allow their use in biosensing applications. We demonstrate their application for the detection of cortisol in solution, upon gate electrode functionalization with anti-cortisol antibodies. This is a robust and cost-effective methodology that sets the ground for a SWCNT/BSA-based biosensing platform that allows overcoming many limitations of standard SWCNTs biosensor fabrications.

Electrochemical Affinity Biosensors: Pervasive Devices with Exciting Alliances and Horizons Ahead

Electrochemical affinity biosensors are evolving at breakneck speed, strengthening and colonizing more and more niches and drawing unimaginable roadmaps that increasingly make them protagonists of our daily lives. They achieve this by combining their intrinsic attributes with those acquired by leveraging the significant advances that occurred in (nano)materials technology, bio(nano)materials and nature-inspired receptors, gene editing and amplification technologies, and signal detection and processing techniques. The aim of this Perspective is to provide, with the support of recent representative and illustrative literature, an updated and critical view of the repertoire of opportunities, innovations, and applications offered by electrochemical affinity biosensors fueled by the key alliances indicated. In addition, the imminent challenges that these biodevices must face and the new directions in which they are envisioned as key players are discussed.

Advancements in Biosensors Based on the Assembles of Small Organic Molecules and Peptides

Over the past few decades, molecular self-assembly has witnessed tremendous progress in a variety of biosensing and biomedical applications. In particular, self-assembled nanostructures of small organic molecules and peptides with intriguing characteristics (e.g., structure tailoring, facile processability, and excellent biocompatibility) have shown outstanding potential in the development of various biosensors. In this review, we introduced the unique properties of self-assembled nanostructures with small organic molecules and peptides for biosensing applications. We first discussed the applications of such nanostructures in electrochemical biosensors as electrode supports for enzymes and cells and as signal labels with a large number of electroactive units for signal amplification. Secondly, the utilization of fluorescent nanomaterials by self-assembled dyes or peptides was introduced. Thereinto, typical examples based on target-responsive aggregation-induced emission and decomposition-induced fluorescent enhancement were discussed. Finally, the applications of self-assembled nanomaterials in the colorimetric assays were summarized. We also briefly addressed the challenges and future prospects of biosensors based on self-assembled nanostructures.

Single-atom nanozyme-based electrochemical sensors for health and food safety monitoring

Electrochemical sensors and biosensors play an important role in many fields, including biology, clinical trials, and food industry. For health and food safety monitoring, accurate and quantitative sensing is needed to ensure that there is no significantly negative impact on human health. It is difficult for traditional sensors to meet these requirements. In recent years, single-atom nanozymes (SANs) have been successfully used in electrochemical sensors due to their high electrochemical activity, good stability, excellent selectivity and high sensitivity. Here, we first summarize the detection principle of SAN-based electrochemical sensors. Then, we review the detection performances of small molecules on SAN-based electrochemical sensors, including H₂O₂, dopamine (DA), uric acid (UA), glucose, H₂S, NO, and O₂. Subsequently, we put forward the optimization strategies to promote the development of SAN-based electrochemical sensors. Finally, the challenges and prospects of SAN-based sensors are proposed.

In situ synthesis of polythiophene encapsulated 2D hexagonal boron nitride nanocomposite based electrochemical transducer for detection of 5-fluorouracil with high selectivity

It is difficult for the scientific community to develop a nonenzymatic sensing platform for extremely sensitive and selective detection of specific biomolecules, antibiotics, food adulterants, heavy metals, etc. One of the most significant chemotherapy drugs, 5-fluorouracil (5-Fu), which is used to treat solid malignancies, has a fluorine atom in the fifth position of the uracil molecule. Recognizing the secure and effective dosing of drugs for chemotherapy continues to be a critical concern in cancer disease management. The maintenance of the optimal 5-Fu concentration is dependent on the presence of 5-Fu in biofluids. Herein we reported a conducting polymer encapsulated 2D material, PTh/h-BN for the efficient electrochemical detection of anticancer drug 5-Fu. Furthermore, the synthesized PTh/h-BN nanocomposite was confirmed by the High-Resolution Transmission Electron Microscope (HR-TEM), High-Resolution Scanning Electron Microscope (HR-SEM), X-ray diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FT-IR). The electrical resistance of PTh/h-BN modified GCE and its sensing performance towards 5-Fu were tested using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) studies respectively. The analytical performance of our proposed catalyst was tested using Differential Pulse Voltammetry (DPV), and the amperometry (i-t curve) method. From the results, our proposed PTh/h-BN nanocomposite-modified GCE shows enhanced sensing performance due to higher redox peak currents, large active surface area, and high electrical conductivity. Moreover, the nanohybrid shows enhanced sensing performances with quick response time, wide linear range, the lowest limit of detection, high sensitivity, and high selectivity in the presence of various interferents. Finally, the practical applicability of the proposed sensor was tested with real-world samples with very good recovery percentages.

Recent Developments in Electrochemical Sensors for the Detection of Antibiotic-Resistant Bacteria

The development of efficient point-of-care (POC) diagnostic tools for detecting infectious diseases caused by destructive pathogens plays an important role in clinical and environmental monitoring. Nevertheless, evolving complex and inconsistent antibiotic-resistant species mire their drug efficacy. In this regard, substantial effort has been expended to develop electrochemical sensors, which have gained significant interest for advancing POC testing with rapid and accurate detection of resistant bacteria at a low cost compared to conventional phenotype methods. This review concentrates on the recent developments in electrochemical sensing techniques that have been applied to assess the diverse latent antibiotic resistances of pathogenic bacteria. It deliberates the prominence of biorecognition probes and tailor-made nanomaterials used in electrochemical antibiotic susceptibility testing (AST). In addition, the bimodal functional efficacy of nanomaterials that can serve as potential transducer electrodes and the antimicrobial agent was investigated to meet the current requirements in designing sensor module development. In the final section, we discuss the challenges with contemporary AST sensor techniques and extend the key ideas to meet the demands of the next POC electrochemical sensors and antibiotic design modules in the healthcare sector.

Printed graphene-based electrochemical sensor with integrated paper microfluidics for rapid lidocaine detection in blood

Topical lidocaine patches are commonly used to relieve pain and suffering in various clinical and household settings. Despite its extensive use, excessive skin absorption during numbing or pain reduction procedures can cause systemic toxicity, which can lead to life-threatening conditions. Rapid and reliable monitoring of escalating levels of lidocaine in the blood could help management/prevention of lidocaine overdose and its associated complications. To address this need, here we have developed a disposable point-of-care (POC) diagnostic platform composed of an integrated graphene-based electrochemical sensor with paper-based microfluidics for rapid detection of lidocaine levels in serum and blood samples. The fabrication process takes advantage of advanced, scalable manufacturing techniques, including printing, laser processing, and nondestructive near infrared (NIR) drying. The sensitivity tests of the platform revealed a sensitivity of ∼0.2 μA μM^-1 towards lidocaine concentrations in the clinically relevant range (1-100 μM) in both complex matrix fluids of serum and blood with high cross specificity in the presence of the interfering analytes. This proof-of-concept platform could be regarded as the first step toward the development of low-cost and translational POC devices that could help in better pain management and reduce potential side effects or misuse of analgesics.

DNA Antiadhesive Layer for Reusable Plasmonic Sensors: Nanostructure Pitch Effect

A long-term reusable sensor that provides the opportunity to easily regenerate the active surface and minimize the occurrence of undesired absorption events is an appealing solution that helps to cut down the costs and improve the device performances. Impressive advances have been made in the past years concerning the development of novel cutting-edge sensors, but the reusability can currently represent a challenge. Direct shielding of the sensor surface is not always applicable, because it can impact the device performance. This study reports an antiadhesive layer (AAL) made of 90 mg/mL DNA sodium salt from salmon testes (ssstDNA) for passivating gold plasmonic sensor surfaces. Our gold two-dimensional (2D) nanostructured plasmonic metasurfaces modified with AAL were used for DNA quantification. AAL is thin enough that the plasmonic sensor remains sensitive to subsequent deposition of DNA, which serves as an analyte. AAL protects the gold surface from unwanted nonspecific adsorption by enabling wash-off of the deposited analyte after analysis and thus recovery of the LSPR peak position (rLSPR). The calibration curve obtained on a single nanostructure (Achiral Octupolar, 100 nm pitch) gave an LOD = 105 ng/mL and an extraordinary dynamic range, performances comparable or superior to those of commercial UV-vis spectrometers for acid nucleic dosage. Two different analytes were tested: ssstDNA (∼2000 bp) in deionized water and double-strand DNA (dsDNA) of 546-1614 bp in 100 mM Tris buffer and 10 mM MgCl₂. The two nanostructures (Achiral Octupolar 25 and 100) were found to have the same sensitivity to DNA in deionized water but different sensitivity to DNA in a salt/buffer solution, opening a potential for solute discrimination. To the best of our knowledge, this is the first report on the use of AAL made of several kilobase-pairs-long dsDNA to produce a reusable plasmonic sensor. The working principle and limitations are drawn based on the LSPR and SERS study.

Diagnostic Approaches For COVID-19: Lessons Learned and the Path Forward

Coronavirus disease 2019 (COVID-19) is a transmitted respiratory disease caused by the infection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although humankind has experienced several outbreaks of infectious diseases, the COVID-19 pandemic has the highest rate of infection and has had high levels of social and economic repercussions. The current COVID-19 pandemic has highlighted the limitations of existing virological tests, which have failed to be adopted at a rate to properly slow the rapid spread of SARS-CoV-2. Pandemic preparedness has developed as a focus of many governments around the world in the event of a future outbreak. Despite the largely widespread availability of vaccines, the importance of testing has not diminished to monitor the evolution of the virus and the resulting stages of the pandemic. Therefore, developing diagnostic technology that serves as a line of defense has become imperative. In particular, that test should satisfy three criteria to be widely adopted: simplicity, economic feasibility, and accessibility. At the heart of it all, it must enable early diagnosis in the course of infection to reduce spread. However, diagnostic manufacturers need guidance on the optimal characteristics of a virological test to ensure pandemic preparedness and to aid in the effective treatment of viral infections. Nanomaterials are a decisive element in developing COVID-19 diagnostic kits as well as a key contributor to enhance the performance of existing tests. Our objective is to develop a profile of the criteria that should be available in a platform as the target product. In this work, virus detection tests were evaluated from the perspective of the COVID-19 pandemic, and then we generalized the requirements to develop a target product profile for a platform for virus detection.

Laccase-mimicking Mn-Cu hybrid nanoflowers for paper-based visual detection of phenolic neurotransmitters and rapid degradation of dyes

Background

Laccase-based biosensors are efficient for detecting phenolic compounds. However, the instability and high cost of laccases have hindered their practical utilization.

Results

In this study, we developed hierarchical manganese dioxide–copper phosphate hybrid nanoflowers (H–Mn–Cu NFs) as excellent laccase-mimicking nanozymes. To synthesize the H–Mn–Cu NFs, manganese dioxide nanoflowers (MnO₂ NFs) were first synthesized by rapidly reducing potassium permanganate using citric acid. The MnO₂ NFs were then functionalized with amine groups, followed by incubation with copper sulfate for three days at room temperature to drive the coordination interaction between the amine moieties and copper ions and to induce anisotropic growth of the petals composed of copper phosphate crystals, consequently yielding H–Mn–Cu NFs. Compared with those of free laccase, at the same mass concentration, H–Mn–Cu NFs exhibited lower K_m (~ 85%) and considerably higher V_max (~ 400%), as well as significantly enhanced stability in the ranges of pH, temperature, ionic strength, and incubation periods evaluated. H–Mn–Cu NFs also catalyzed the decolorization of diverse dyes considerably faster than the free laccase. Based on these advantageous features, a paper microfluidic device incorporating H–Mn–Cu NFs was constructed for the convenient visual detection of phenolic neurotransmitters, including dopamine and epinephrine. The device enabled rapid and sensitive quantification of target neurotransmitters using an image acquired using a smartphone.

Conclusions

These results clearly show that H–Mn–Cu NFs could be potential candidates to replace natural laccases for a wide range of applications in biosensing, environmental protection, and biotechnology.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01560-0.

From Prevention to Therapy: A Roadmap of Nanotechnologies to Stay Ahead of Future Pandemics

Several recent viral outbreaks, culminating in the COVID-19 pandemic, have illustrated the need for comprehensive improvement in the detection, control, and treatment of emerging viruses that exhibit the potential to cause epidemics. Nanotechnology approaches have the potential to make major contributions in all these areas. This perspective is intended to outline how nanotechnology can be employed to improve upon respiratory disease detection and containment measures, and therapeutics, with a particular emphasis on applications that can address key areas, including home diagnostics, contact tracing, and the evaluation of durability of vaccine protection over time and against future variants. Nanotechnology offers potent tools to address these needs, but further research is required to validate these applications to address needs of future epidemics.

Comparison of Mechanical Properties of a Self-Adhesive Composite Cement and a Heated Composite Material

(1) Background: Due to the limitations of composite cements, the authors carried out tests to compare such materials with preheated composite materials because the latter may be an alternative to cements in the adhesive cementation procedure. (2) Methods: The materials used in the adhesive cementation procedure, i.e., Enamel Plus Hri (Micerium, Avegno, Italy), a heated composite material, and RelyX U200 Automix (3M, Maplewood, MN, USA), a dual composite cement, were tested for microhardness, compressive strength, flexural strength, diametral compressive strength, and elastic modulus. Composite material was heated to the temperature of 50 degrees Celsius before polymerisation. (3) Results: Higher values of microhardness (by 67.36%), compressive strength (by 41.84%), elastic modulus (by 17.75%), flexural strength (by 36.03%), and diametral compressive strength (by 45.52%) were obtained using the Enamel Plus Hri composite material compared to the RelyX U200 self-adhesive cement. The survey results revealed statistically significant differences. (4) Conclusions: Due to its better mechanical properties, the heated composite material (Enamel Plus Hri) is a beneficial alternative to composite cements in the indirect restoration placement procedure. As the strength parameters of the heated composite material increase, a higher resistance to the compressive and bending forces present in the oral cavity, and hence a greater durability of the created prosthetic reconstructions can be expected.

Bevacizumab-Laden Nanofibers Simulating an Antiangiogenic Niche to Improve the Submuscular Stability of Stem Cell Engineered Cartilage

Bone marrow stem cells (BMSCs) engineered cartilage (BEC) is prone to endochondral ossification in a submuscular environment due to the process of vascular infiltration, which limits its application in repairing tracheal cartilage defects. Bevacizumab, an antitumor drug with pronounced antiangiogenic activity, is successfully laden into a poly(L-lactide-co-caprolactone) system to prepare bevacizumab-laden nanofiber (BevNF) characterized by 5% and 10% bevacizumab concentrations. The in vitro results reveal that a sustained release of bevacizumab can be realized from BevNF, exhibiting inhibitive cytotoxicity toward human umbilical vein endothelial cells whereas non-cytotoxicity toward BMSCs-induced chondrocytes. A model is also established by encapsulating BEC within BevNF, aiming to realize an antiangiogenic niche under conditions of sustained and localized release of bevacizumab to inhibit the process of vascular invasion, resulting in the eventual stabilization of the cartilaginous phenotype and promotion of the process of cartilage maturation in the submuscular environment. These results also confirm that the chondrogenesis stability of BEC increases with an increase in the bevacizumab concentration, and 10% BevNF is sufficient to protect BEC from vascularization. This demonstrates that the use of BevNF can potentially help develop an effective strategy for regulating the submuscular stability of BEC to repair the defects formed in tracheal cartilage.

Glaucoma Characterization by Machine Learning of Tear Metabolic Fingerprinting

Glaucoma is a common optic neuropathy disease affecting over 76 million people. Both timely diagnosis and progression monitoring are critical but challenging. Conventional characterization of glaucoma needs a combination of methods, calling for tedious procedures and experienced doctors. Herein, a platform through machine learning of tear metabolic fingerprinting (TMF) using nanoparticle enhanced laser desorption-ionization mass spectrometry is built. Direct TMF is obtained noninvasively, with fast speed and high reproducibility, using trace tear samples (down to 10 nL). Consequently, glaucoma patients are screened against healthy controls with the area under the curve (AUC) of 0.866, through machine learning of TMF. Further, primary open-angle glaucoma (POAG) is differentiated from primary angle-closure glaucoma (PACG) and an early-stage POAG is identified. Finally, a biomarker panel of six metabolites for glaucoma characterization (including screening, subtyping, and early diagnosis) with AUC of 0.827-0.891 is constructed, showing related metabolic pathways. The work will provide insights into eye diseases not limited to glaucoma.

Porous Inorganic Materials for Bioanalysis and Diagnostic Applications

Porous inorganic materials play an important role in adsorbing targeted analytes and supporting efficient reactions in analytical science. The detection performance relies on the structural properties of porous materials, considering the tunable pore size, shape, connectivity, etc. Herein, we first clarify the enhancement mechanisms of porous materials for bioanalysis, concerning the detection sensitivity and selectivity. The diagnostic applications of porous material-assisted platforms by coupling with various analytical techniques, including electrochemical sensing, optical spectrometry, and mass spectrometry, etc., are then reviewed. We foresee that advanced porous materials will bring far-reaching implications in bioanalysis toward real-case applications, especially as diagnostic assays in clinical settings.