Microfluidic Paper-Based Blood Plasma Separation Device as a Potential Tool for Timely Detection of Protein Biomarkers.

A current challenge regarding microfluidic paper-based analytical devices (µPAD) for blood plasma separation (BPS) and electrochemical immunodetection of protein biomarkers is how to achieve a µPAD that yields enough plasma to retain the biomarker for affinity biosensing in a functionalized electrode system. This paper describes the development of a BPS µPAD to detect and quantify the S100B biomarker from peripheral whole blood. The device uses NaCl functionalized VF2 filter paper as a sample collection pad, an MF1 filter paper for plasma retention, and an optimized microfluidic channel geometry. An inverted light microscope, scanning electron microscope (SEM), and image processing software were used for visualizing BPS efficiency. A design of experiments (DOE) assessed the device's efficacy using an S100B ELISA Kit to measure clinically relevant S100B concentrations in plasma. The BPS device obtained 50 µL of plasma from 300 µL of whole blood after 3.5 min. The statistical correlation of S100B concentrations obtained using plasma from standard centrifugation and the BPS device was 0.98. The BPS device provides a simple manufacturing protocol, short fabrication time, and is capable of S100B detection using ELISA, making one step towards the integration of technologies aimed at low-cost POC testing of clinically relevant biomarkers.

TBISTAT: An open-source, wireless portable, electrochemical impedance spectroscopy capable potentiostat for the point-of-care detection of S100B in plasma samples.

Point-of-Care (POC) testing for biomarker detection demands techniques that are easy to use, readily available, low-cost, and with rapid response times. This paper describes the development of a fully open-source, modular, wireless, battery-powered, smartphone-controlled, low-cost potentiostat capable of conducting electrochemical impedance spectroscopy for the electrochemical detection of the S100B protein captured in an ANTI-S100B functionalized thin-film gold interdigitated electrode platform to support traumatic brain injury diagnosis and treatment. EIS results from the developed potentiostat were validated with a commercial benchtop potentiostat by comparing impedance magnitude and phase values along the EIS frequency range. In addition, an experimental design was performed for detecting S100B in spiked human plasma samples with S100B concentrations of clinical utility, and a calibration curve was found for quantifying S100B detection. No statistically significant differences were found between EIS results from the developed potentiostat and the commercial potentiostat. Statistically significant differences in the changes in charge transfer resistance signal between each tested S100B concentration (p < 0.05) were found, with a limit of detection of 35.73 pg/mL. The modularity of the proposed potentiostat allows easier component changes according to the application demands in power, frequency excitation ranges, wireless communication protocol, signal amplification and transduction, precision, and sampling frequency of ADC, among others, when compared to state-of-the-art open-source EIS potentiostats. In addition, the use of minimal, easy acquirable open-source hardware and software, high-level filtering, accurate ADC, Fast Fourier Transform with low spectral leakage, wireless communication, and the simple user interface provides a framework for facilitating EIS analysis and developing new affordable instrumentation for POC biosensors integrated systems.

Electrochemical Immunosensor for the Quantification of S100B at Clinically Relevant Levels Using a Cysteamine Modified Surface.

Neuronal damage secondary to traumatic brain injury (TBI) is a rapidly evolving condition, which requires therapeutic decisions based on the timely identification of clinical deterioration. Changes in S100B biomarker levels are associated with TBI severity and patient outcome. The S100B quantification is often difficult since standard immunoassays are time-consuming, costly, and require extensive expertise. A zero-length cross-linking approach on a cysteamine self-assembled monolayer (SAM) was performed to immobilize anti-S100B monoclonal antibodies onto both planar (AuEs) and interdigitated (AuIDEs) gold electrodes via carbonyl-bond. Surface characterization was performed by atomic force microscopy (AFM) and specular-reflectance FTIR for each functionalization step. Biosensor response was studied using the change in charge-transfer resistance (Rct) from electrochemical impedance spectroscopy (EIS) in potassium ferrocyanide, with [S100B] ranging 10-1000 pg/mL. A single-frequency analysis for capacitances was also performed in AuIDEs. Full factorial designs were applied to assess biosensor sensitivity, specificity, and limit-of-detection (LOD). Higher Rct values were found with increased S100B concentration in both platforms. LODs were 18 pg/mL(AuES) and 6 pg/mL(AuIDEs). AuIDEs provide a simpler manufacturing protocol, with reduced fabrication time and possibly costs, simpler electrochemical response analysis, and could be used for single-frequency analysis for monitoring capacitance changes related to S100B levels.

The delayed detection of an acute neurological worsening increases traumatic brain injury lethality / [La detección tardía del deterioro neurológico agudo incrementa la letalidad por trauma craneoencefálico.]

Introduction: Traumatic brain injury is a leading worldwide cause of death and disability in young people. Severity classification is based on the Glasgow Coma Scale. However, the neurological worsening in an acute setting does not always correspond to the initial severity suggesting an underestimation of the real magnitude of the injury. Objective: To study the correlation between the initial severity according to the Glasgow Coma Scale and the patient outcome in the context of different clinical and tomography variables. Materials and methods: We analyzed a retrospective cohort of 490 patients with closed traumatic brain injury requiring a stay in the intensive care unit of two third-level hospitals in Barranquilla. The risk was estimated by calculating the OR (95% CI). The significance level was established at an alpha value of 0.05. Results: Forty-one percent of all patients required orotracheal intubation; 51.2% were initially classified with moderate trauma and 6,0% as mild. The delay in the aggressive management of the traumas affected mainly those patients with traumas classified as moderate in whom lethality increased to 100% when there was delay in the detection of the neurological worsening and in the establishment of the aggressive treatment beyond 4 to 8 hours while the lethality in patients who received this treatment within the first hour reduced to <20%. Conclusions: The risk of lethality in traumatic brain injury increases with the delayed detection of neurological worsening in an acute setting, especially when aggressive management is performed after the first hour post-trauma.

Introducción. El trauma craneoencefálico es una de las principales causas de muerte y discapacidad en adultos jóvenes. Su gravedad se define según la escala de coma de Glasgow. Sin embargo, el deterioro neurológico agudo no siempre concuerda con la gravedad inicial indicada por la escala, lo que implica una subestimación de la magnitud real de la lesión. Objetivo. Estudiar la correlación entre la gravedad inicial del trauma craneoencefálico según la escala de coma de Glasgow y la condición final del paciente, en el contexto de diferentes variables clínicas y de los hallazgos de la tomografía. Materiales y métodos. Se analizó una cohorte retrospectiva de 490 pacientes con trauma craneoencefálico cerrado que requirieron atención en la unidad de cuidados intensivos de dos centros de tercer nivel de Barranquilla. La estimación del riesgo se estableció con la razón de momios (odds ratio, OR) y un intervalo de confianza (IC) del 95 %. Se utilizó un alfa de 0,05 como nivel de significación. Resultados. El 41,0 % de los pacientes requirió intubación endotraqueal; el 51,2 % había presentado traumas inicialmente clasificados como moderados y, el 6,0 %, como leves. El retraso en la implementación de un tratamiento agresivo afectó principalmente a aquellos con trauma craneoencefálico moderado, en quienes la letalidad aumentó al 100 % cuando no se detectó a tiempo el deterioro neurológico y, por lo tanto, el tratamiento agresivo se demoró más de 4 a 8 horas. Por el contrario, la letalidad fue de menos de 20 % cuando se brindó el tratamiento agresivo en el curso de la primera hora después del trauma. Conclusiones. El riesgo de letalidad del trauma craneoencefálico aumentó cuando el deterioro neurológico se detectó tardíamente y el tratamiento agresivo se inició después de transcurrida la primera hora a partir del trauma.

La detección tardía del deterioro neurológico agudo incrementa la letalidad por trauma craneoencefálico / The delayed detection of an acute neurological worsening increases traumatic brain injury lethality

Introducción. El trauma craneoencefálico es una de las principales causas de muerte y discapacidad en adultos jóvenes. Su gravedad se define según la escala de coma de Glasgow. Sin embargo, el deterioro neurológico agudo no siempre concuerda con la gravedad inicial indicada por la escala, lo que implica una subestimación de la magnitud real de la lesión. Objetivo. Estudiar la correlación entre la gravedad inicial del trauma craneoencefálico según la escala de coma de Glasgow y la condición final del paciente, en el contexto de diferentes variables clínicas y de los hallazgos de la tomografía. Materiales y métodos. Se analizó una cohorte retrospectiva de 490 pacientes con trauma craneoencefálico cerrado que requirieron atención en la unidad de cuidados intensivos de dos centros de tercer nivel de Barranquilla. La estimación del riesgo se estableció con la razón de momios (odds ratio, OR) y un intervalo de confianza (IC) del 95 %. Se utilizó un alfa de 0,05 como nivel de significación. Resultados. El 41,0 % de los pacientes requirió intubación endotraqueal; el 51,2 % había presentado traumas inicialmente clasificados como moderados y, el 6,0 %, como leves. El retraso en la implementación de un tratamiento agresivo afectó principalmente a aquellos con trauma craneoencefálico moderado, en quienes la letalidad aumentó al 100 % cuando no se detectó a tiempo el deterioro neurológico y, por lo tanto, el tratamiento agresivo se demoró más de 4 a 8 horas. Por el contrario, la letalidad fue de menos de 20 % cuando se brindó el tratamiento agresivo en el curso de la primera hora después del trauma. Conclusiones. El riesgo de letalidad del trauma craneoencefálico aumentó cuando el deterioro neurológico se detectó tardíamente y el tratamiento agresivo se inició después de transcurrida la primera hora a partir del trauma.

Introduction: Traumatic brain injury is a leading worldwide cause of death and disability in young people. Severity classification is based on the Glasgow Coma Scale. However, the neurological worsening in an acute setting does not always correspond to the initial severity suggesting an underestimation of the real magnitude of the injury. Objective: To study the correlation between the initial severity according to the Glasgow Coma Scale and the patient outcome in the context of different clinical and tomography variables. Materials and methods: We analyzed a retrospective cohort of 490 patients with closed traumatic brain injury requiring a stay in the intensive care unit of two third-level hospitals in Barranquilla. The risk was estimated by calculating the OR (95% CI). The significance level was established at an alpha value of 0.05. Results: Forty-one percent of all patients required orotracheal intubation; 51.2% were initially classified with moderate trauma and 6,0% as mild. The delay in the aggressive management of the traumas affected mainly those patients with traumas classified as moderate in whom lethality increased to 100% when there was delay in the detection of the neurological worsening and in the establishment of the aggressive treatment beyond 4 to 8 hours while the lethality in patients who received this treatment within the first hour reduced to <20%. Conclusions: The risk of lethality in traumatic brain injury increases with the delayed detection of neurological worsening in an acute setting, especially when aggressive management is performed after the first hour post-trauma.

Revisión de tema: Biomarcadores neuronales y gliales como estrategia de clasificación cuantitativa de la severidad del trauma craneoencefálico / Review: Neuronal and glial biomarkers as quantitative approach to classify the severity of traumatic brain injury

Resumen Se ha puesto de relieve el potencial de la evaluación neurológica temprana inexacta de la severidad en pacientes con trauma craneoencefálico, ya que en algunos subgrupos de pacientes la gravedad de la lesión puede ser sobreestimada y en otros subestimada, lo cual ha llevado a la búsqueda de biomarcadores asociados a la lesión cerebral temprana. La investigación en este campo ha aumentado de forma exponencial en los últimos 20 años, con la mayoría de las publicaciones sobre el tema en los últimos 10 años, evidenciando diferentes resultados, que van desde hallazgos prometedores a otros no concluyentes. Un biomarcador ideal debería poder demostrar una alta sensibilidad y especificidad para la lesión cerebral, entre otros aspectos. En la actualidad no se cuenta con un biomarcador único capaz de predecir el deterioro clínico de los pacientes que presente tanto una alta sensibilidad como especificidad; en lugar de ello se debe disponer de un panel de marcadores que reflejen diferentes aspectos de la injuria traumática. Este trabajo presenta una revisión sobre los biomarcadores más prometedores como predictores de severidad del trauma craneoencefálico, explorando su naturaleza, ubicación a nivel encefálico, sus concentraciones basales, su vida media y los métodos por los cuales estos pueden ser cuantificados una vez atraviesan la barrera hematoencefálica.

Abstract It has been highlighted the potential of early neurological inaccurate assessment of severity in patients with head trauma; in some cases, for example, the severity of the injury is overestimated or underestimated. The aforementioned situation has led to the search of biomarkers associated with early brain injury. Research in this field has exponentially increased over the past 20 years, with a higher publication ramp in the last 10 years. The results range from promising findings to other sometime inconclusive. An ideal biomarker should be able to demonstrate high sensitivity and specificity for brain injury, among others aspects. Literature has shown that there is not a single biomarker that can predict patient's clinical decline with high sensitivity and specificity correlation. Instead, it is required to use a panel of markers that reflect different aspects of traumatic brain injury. In this paper, we conducted a review of the most promising biomarkers studied as predictors of severity of head trauma, with special focus on their nature, location, basal concentrations, blood half-life and methods by which they can be quantified in blood samples.