Label-free electrochemical biosensor for determination of procalcitonin based on graphene-wrapped Co nanoparticles encapsulated in carbon nanobrushes coupled with AuPtCu nanodendrites

Structural and sensing properties of HfxZr1-xO2 films prepared through a spin-coating sol-gel method for pH and procalcitonin detection

In this study, HfxZr1-xO2 (HZO) sensing films were deposited on highly doped n+-type Si substrates using the spin-coating sol-gel method. These films were designed for use in extended-gate field-effect transistor (EGFET) pH sensors and procalcitonin (PCT) detection, a key biomarker for sepsis diagnosis. To investigate the effects of thermal processing on the structural and functional properties of the films, rapid thermal annealing (RTA) was performed at temperatures ranging from 600 to 800 °C. Comprehensive material characterization through X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, and transmission electron microscopy revealed a strong correlation between the film's structural properties and its sensing performance. The film annealed at 700 °C demonstrated excellent performance, achieving the highest pH sensitivity (63.69 mV/pH), the lowest drift rate (0.24 mV/h), and minimal hysteresis (0.3 mV). Moreover, for PCT detection, N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide-acivated PCT antibodies were immobilized on a 3-aminopropyltriethoxysilane-functionalized HZO film, enabling specific antigen binding. The resulting HZO-based EGFET biosensor showed high sensitivity (13.6 mV/pCPCT) across a broad dynamic range (10 fg/mL to 1 μg/mL). These findings highlight the potential of HZO sensing films for high-performance pH sensing and their integration into biomedical diagnostics, particularly for PCT detection in sepsis diagnosis.

Advances of immunosensors based on noble metal composite materials for detecting procalcitonin

Procalcitonin (PCT) is a reliable biomarker for diagnosing and monitoring bacterial infections and sepsis. PCT exhibits good stability both in vivo and in vitro, and its levels drastically increase in response to bacterial infection or inflammatory reactions in the human body, making it a dependable indicator for sepsis diagnosis and monitoring with significant implications for clinical diagnosis and treatment guidance. Currently, immunosensors are widely utilized in PCT detection due to their high sensitivity and low detection limits. Noble metals, because of their excellent electronic conductivity, biocompatibility, and superior physicochemical properties, are extensively combined with other materials to play a pivotal role in the construction of PCT immunosensors. This review summarizes the research progress on PCT antigen immunosensors based on noble metal composite materials, encompassing the classification and principles of immunosensors. Starting from noble metals, which are widely used as electrode materials in sensors, the review categorizes and discusses the carbon materials, metal oxides, metal sulfides, and other composites with noble metals. The review also elaborates on the influence of sensitive materials on the performance of immunosensors. Finally, the review discusses and anticipates the challenges and future opportunities for the research on PCT antigen immunosensors using noble metal-composite nanomaterials, providing new insights and directions for their application in the treatment and clinical management of sepsis and other diseases.

Challenges and Advances in Biomarker Detection for Rapid and Accurate Sepsis Diagnosis: An Electrochemical Approach

Sepsis is a life-threatening condition with high mortality rates due to delayed treatment of patients. The conventional methodology for blood diagnosis takes several hours, which suspends treatment, limits early drug administration, and affects the patient's recovery. Thus, rapid, accurate, bedside (onsite), economical, and reliable sepsis biomarker reading of the clinical sample is an emergent need for patient lifesaving. Electrochemical label-free biosensors are specific and rapid devices that are able to perform analysis at the patient's bedside; thus, they are considered an attractive methodology in a clinical setting. To reveal their full diagnostic potential, electrode architecture strategies of fabrication are highly desirable, particularly those able to preserve specific antibody-antigen attraction, restrict non-specific adsorption, and exhibit high sensitivity with a low detection limit for a target biomarker. The aim of this review is to provide state-of-the-art methodologies allowing the fabrication of ultrasensitive and highly selective electrochemical sensors for sepsis biomarkers. This review focuses on different methods of label-free biomarker sensors and discusses their advantages and disadvantages. Then, it highlights effective ways of avoiding false results and the role of molecular labels and functionalization. Recent literature on electrode materials and antibody grafting strategies is discussed, and the most efficient methodology for overcoming the non-specific attraction issues is listed. Finally, we discuss the existing electrode architecture for specific biomarker readers and promising tactics for achieving quick and low detection limits for sepsis biomarkers.

Dendritic quinary PtRhMoCoFe high-entropy alloy as a robust immunosensing nanoplatform for ultrasensitive detection of biomarker

Recently, high-entropy alloys have superior physicochemical properties as compared to conventional alloys for their glamorous "cocktail effect". Nevertheless, they are scarcely applied to electrochemical immunoassays until now. Herein, uniform PtRhMoCoFe high-entropy alloyed nanodendrites (HEANDs) were synthesized by a wet-chemical co-reduction method, where glucose and oleylamine behaved as the co-reducing agents. Then, a series of characterizations were conducted to illustrate the synergistic effect among multiple metals and fascinating structural characteristics of PtRhMoCoFe HEANDs. The obtained high-entropy alloy was adopted to build a electrochemical label-free biosensor for ultrasensitive bioassay of biomarker cTnI. In the optimized analytical system, the resultant sensor exhibited a dynamic linear range of 0.0001-200 ng mL-1 and a low detection limit of 0.0095 pg mL-1 (S/N = 3). Eventually, this sensing platform was further explored in serum samples with satisfied recovery (102.0 %). This research renders some constructive insights for synthesis of high-entropy alloys and their expanded applications in bioassays and bio-devices.

Simple and sensitive sandwich-like voltammetric immunosensing of procalcitonin

Procalcitonin (PCT) is a reliable biomarker in the early diagnosis of septicemia, pyemia and stroke-associated pneumonia. In this work, through preparing β-cyclodextrin/graphene (CD/GN) nanohybrid as carrier and amplifier simultaneously to band antibodies and probe molecules, a simple and innovative sandwich-like voltammetric immunosensor was proposed for the sensitive and effective determination of PCT. Owing to the host-guest recognition property, the antibodies of PCT can enter into the CD cavities to generate a stable complex; meanwhile, aminopyrene (AP) were introduced as the signal probe and it was adsorbed on the surface of GN via aminopyrine π-πinteraction. Based on the signal change from AP as a response signal which exhibits linearity to the concentration of PCT, a highly sensitive sandwich-type voltammetric immunosensor was developed successfully after optimizing various key parameters. The results demonstrated that the developed sensor had a considerably low detection limit (0.003 pg mL-1) and wide linearity of 0.01 pg mL-1 to 20.0 ng mL-1. This work offered a very simple and sensitive sensing strategy for PCT and other biomarkers via altering the specific antibodies simply, showing great potential applications.

An ultra-sensitive electrochemical biosensor for the detection of procalcitonin in sepsis patients' serum, using a Cu-BHT-based thin film

Procalcitonin (PCT) is a polypeptide produced by the parafollicular cells of the thyroid gland and serves as a vital marker for the diagnosis and treatment of sepsis and other infectious diseases, as well as multiple organ failure, due to its high expression levels in affected patients. This article reports on a highly sensitive electrochemical biosensor based on MOF composite materials, based on Cu-BHT, for detecting PCT levels. The surface of the glassy carbon electrode may have better charge transfer resistance owing to the nano-composite material made of Cu-BHT, chitosan, and AuNPs. At the same time, the anti-PCT antibody may also be covalently bonded to the composite material and measure PCT concentration using electrochemical impedance spectroscopy (EIS). The results of the investigation demonstrate that the sensor's response has excellent linear conjunction with the logarithm of PCT concentration under optimum circumstances. The detection limit (LOD) is 14.579 × 10-9 μg/mL, and the linear range of detection is 10-7 μg/mL to 10-1 μg/mL. Simultaneously, we successfully applied this method to detect serum PCT before and after treatment in different sepsis patients and compared it with chemiluminescence immunoassay. The findings indicate that the proposed method holds promising potential for timely diagnosis and treatment of sepsis patients.

Chitosan modified graphene field-effect transistor biosensor for ultrasensitive procalcitonin detection

Sepsis is a systemic inflammatory response caused by a bacterial infection that often leading to tissue damage, organ failure and death. Procalcitonin (PCT), as a peptide precursor to hormones, is the main biomarker to identification of the sepsis. In this study, a chitosan modified graphene field transistor (CTS-GFET) was established and first time used for PCT ultra-sensitive detection. CTS was functionalized on the GFET channel surface to immobilized anti-PCT by glutaraldehyde. This biosensor exhibited the detection limit as low as 0.82 ag/mL in PBS, which exhibited 3 times enhancement compared with GFET biosensors. The enhancement mechanisms of CTS-GFET were studied by electrical theoretical model. In addition, the CTS-GFET biosensor was successfully applied to quantify the concentration of the PCT in human serum samples, indicating the potential use in clinical application.

Nanobiosensors for procalcitonin (PCT) analysis

BACKGROUND

Procalcitonin (PCT) is a critical biomarker that is released in response to bacterial infections and can be used to differentiate the pathogenesis of the infectious process.

OBJECTIVE

In this article, we provide an overview of recent advances in PCT biosensors, highlighting different approaches for biosensor construction, different immobilization methods, advantages and roles of different matrices used, analytical performance, and PCT biosensor construction. Also, we will explain PCT biosensors sensible limits of detection (LOD), linearity, and other analytical characteristics. Future prospects for the development of better PCT biosensor systems are also discussed.

METHODS

Traditional methods such as capillary electrophoresis, high-performance liquid chromatography, and mass spectrometry are effective in analyzing PCT in the medical field, but they are complicated, time-consuming sample preparation, and require expensive equipment and skilled personnel.

RESULTS

In the past decades, PCT biosensors have emerged as simple, fast, and sensitive tools for PCT analysis in various fields, especially medical fields.

CONCLUSION

These biosensors have the potential to accompany or replace traditional analytical methods by simplifying or reducing sample preparation and making field testing easier and faster, while significantly reducing the cost per analysis.

Electrochemical sensor for hydrogen sulfide detection using electrocatalysis-assisted amplification and chemical reaction-mediated signal enhancement

An ultrasensitive electrochemical biosensing platform has been designed by combining electrocatalysis-assisted H2S amplification with a chemical reaction-mediated electrochemical signal-boosted system for H2S detection based on Cu-Mn(OH)2 hexagonal nanorings. The signal amplification is initiated by an electrocatalysis reaction that can grasp specific H2S substrates and further highly amplify electrochemical signals. Then, the unique chemical reaction is powered by copper ion and generates a large amount of electroactive CuxS products on the electrode surface, thus achieving the multiple amplification of H2S detection. Finally, the Cu-Mn(OH)2 loaded with plenty of electroactive CuxS can be captured on the electrode for further improving the electrochemical signal thus obtaining ultra-high sensitive determination of H2S. The established electrochemical biosensing platform displays a wide analytical range of 0.1 μM to 265 μM with a low detection limit of 0.096 μM. The satisfactory selectivity allows the electrochemical sensor to distinguish H2S from other interfering substances without any complicated pretreatment, even in complex tumor cell samples. Thus, our designed electrocatalysis-assisted amplification strategy offers a powerful analysis toolkit for the early determination of H2S-related disease in clinical diagnosis.

How Extracellular Nano-Vesicles Can Play a Role in Sepsis? An Evidence-Based Review of the Literature

Sepsis is a systemic inflammatory reaction caused by infection. Severe sepsis can lead to multiple organ dysfunction, with a high incidence rate and mortality. The molecular pathogenesis of sepsis is complex and diverse. In recent years, with further study of the role of extracellular vesicles (EVs) in inflammatory diseases, it has been found that EVs play a dual role in the imbalance of inflammatory response in sepsis. Due to the great advantages such as lower toxicity, lower immunogenicity compared with stem cells and better circulation stability, EVs are increasingly used for the diagnosis and treatment of sepsis. The roles of EVs in the pathogenesis, diagnosis and treatment of sepsis were summarized to guide further clinical studies.

One-pot wet-chemical fabrication of 3D urchin-like core-shell Au@PdCu nanocrystals for electrochemical breast cancer immunoassay

Carbohydrate antigen 15-3 (CA15-3) is an important biomarker for early diagnosis of breast cancer. Herein, a label-free electrochemical immunosensor was built based on three-dimensional (3D) urchin-like core-shell Au@PdCu nanocrystals (labeled Au@PdCu NCs) for highly sensitive detection of CA15-3, where K3[Fe(CN)6] behaved as an electroactive probe. The Au@PdCu NCs were synthesized by a simple one-pot wet-chemical approach and the morphology, structures, and electrocatalytic property were investigated by several techniques. The Au@PdCu NCs prepared worked as electrode material to anchor more antibodies and as signal magnification material by virtue of its exceptional catalytic property. The developed biosensor exhibited a wide linear detection range from 0.1 to 300 U mL-1 and a low limit of detection (0.011 U mL-1, S/N = 3) for determination of CA15-3 under the optimal conditions. The established biosensing platform exhibits some insights for detecting other tumor biomarkers in clinical assays and early diagnosis.

NiCoP/g-C3N4 Nanocomposites-Based Electrochemical Immunosensor for Sensitive Detection of Procalcitonin

Herein, an ultra-sensitive and facile electrochemical biosensor for procalcitonin (PCT) detection was developed based on NiCoP/g-C₃N₄ nanocomposites. Firstly, NiCoP/g-C₃N₄ nanocomposites were synthesized using hydrothermal methods and then functionalized on the electrode surface by π-π stacking. Afterward, the monoclonal antibody that can specifically capture the PCT was successfully linked onto the surface of the nanocomposites with a 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-Hydroxysuccinimide (NHS) condensation reaction. Finally, the modified sensor was employed for the electrochemical analysis of PCT using differential Pulse Voltammetry(DPV). Notably, the larger surface area of g-C₃N₄ and the higher electron transfer capacity of NiCoP/g-C₃N₄ endow this sensor with a wider detection range (1 ag/mL to 10 ng/mL) and an ultra-low limit of detection (0.6 ag/mL, S/N = 3). In addition, this strategy was also successfully applied to the detection of PCT in the diluted human serum sample, demonstrating that the developed immunosensors have the potential for application in clinical testing.

Ultrasensitive Photoelectrochemical Immunoassay Strategy Based on Bi2S3/Ag2S for the Detection of the Inflammation Marker Procalcitonin

As an inflammatory marker, procalcitonin (PCT) is more representative than other traditional inflammatory markers. In this work, a highly efficient photoelectrochemical (PEC) immunosensor was constructed based on the photoactive material Bi₂S₃/Ag₂S to realize the sensitive detection of PCT. Bi₂S₃ was prepared by a hydrothermal method, and Ag₂S quantum dots were deposited on the ITO/Bi₂S₃ surface via in situ reduction. Bi₂S₃ is a kind of admirable photoelectric semiconductor nanomaterial on account of its moderate bandgap width and low binding rate of photogenerated electron holes, which can effectively convert light energy into electrical energy. Therefore, based on the energy level matching principle of Bi₂S₃ and Ag₂S, a labeled Bi₂S₃/Ag₂S PEC immunosensor was constructed, and the sensitive detection of PCT was successfully established. The linear detection range of the PEC immunosensor was 0.50 pg∙mL^-1 to 50 ng∙mL^-1, and the minimum detection limit was 0.18 pg∙mL^-1. Compared with the traditional PEC strategy, the proposed PEC immunosensor is simple, convenient, and has good anti-interference, sensitivity, and specificity, which could provide a meaningful theoretical basis and reference value for the clinical detection of PCT.

Detection of COVID-19-related biomarkers by electrochemical biosensors and potential for diagnosis, prognosis, and prediction of the course of the disease in the context of personalized medicine

As a more efficient and effective way to address disease diagnosis and intervention, cutting-edge technologies, devices, therapeutic approaches, and practices have emerged within the personalized medicine concept depending on the particular patient's biology and the molecular basis of the disease. Personalized medicine is expected to play a pivotal role in assessing disease risk or predicting response to treatment, understanding a person's health status, and, therefore, health care decision-making. This work discusses electrochemical biosensors for monitoring multiparametric biomarkers at different molecular levels and their potential to elucidate the health status of an individual in a personalized manner. In particular, and as an illustration, we discuss several aspects of the infection produced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a current health care concern worldwide. This includes SARS-CoV-2 structure, mechanism of infection, biomarkers, and electrochemical biosensors most commonly explored for diagnostics, prognostics, and potentially assessing the risk of complications in patients in the context of personalized medicine. Finally, some concluding remarks and perspectives hint at the use of electrochemical biosensors in the frame of other cutting-edge converging/emerging technologies toward the inauguration of a new paradigm of personalized medicine.

Development of conducting cellulose paper for electrochemical sensing of procalcitonin

An electrochemical paper-based sensor was developed for the detection of bacterial infection (BI)-specific biomarker procalcitonin (PCT). Reduced graphene oxide-gold nanoparticles (rGO-AuNP) and poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were synthesized and were fabricated to a disposable, portable, and inexpensive cellulose fiber paper (CFP) substrate. rGO-AuNP-PEDOT:PSS nanocomposite-modified conductive paper-based biosensing platform was efficaciously fabricated by a constant and simple coating procedure. rGO-AuNP-PEDOT:PSS nanocomposite-modified conductive paper electrode was found to provide a sensitive and conductive substrate for PCT detection. The presence of rGO-AuNP-PEDOT:PSS nanocomposite on CFP substate was investigated by Fourier transform infrared spectrometry, field emission scanning electron microscopy, ultraviolet-visible spectroscopy, and X-ray diffraction studies. The electrochemical behavior of rGO-AuNP-PEDOT:PSS @CFP surface was studied with impedance spectroscopy, cyclic voltammetry, and chronoamperometry techniques. This low-cost paper-based biosensor has a linear range for PCT of 1 × 10³ to 6 × 10⁷ fg mL^-1. This developed sensor exhibited good reproducibility with a relative standard deviation (RSD) of about 3.7%. The proposed CFP-based biosensor has been proven as an accelerated simple point-of-care (POC) exploratory approach for early PCT diagnosis in inadequate areas with limited production facilities, computational techniques, and highly skilled experts.

Emerging Biosensing Technologies towards Early Sepsis Diagnosis and Management

Sepsis is defined as a systemic inflammatory dysfunction strictly associated with infectious diseases, which represents an important health issue whose incidence is continuously increasing worldwide. Nowadays, sepsis is considered as one of the main causes of death that mainly affects critically ill patients in clinical settings, with a higher prevalence in low-income countries. Currently, sepsis management still represents an important challenge, since the use of traditional techniques for the diagnosis does not provide a rapid response, which is crucial for an effective infection management. Biosensing systems represent a valid alternative due to their characteristics such as low cost, portability, low response time, ease of use and suitability for point of care/need applications. This review provides an overview of the infectious agents associated with the development of sepsis and the host biomarkers suitable for diagnosis and prognosis. Special focus is given to the new emerging biosensing technologies using electrochemical and optical transduction techniques for sepsis diagnosis and management.