A compact microelectrode array chip with multiple measuring sites for electrochemical applications.

In this paper we demonstrate the fabrication and electrochemical characterization of a microchip with 12 identical but individually addressable electrochemical measuring sites, each consisting of a set of interdigitated electrodes acting as a working electrode as well as two circular electrodes functioning as a counter and reference electrode in close proximity. The electrodes are made of gold on a silicon oxide substrate and are passivated by a silicon nitride membrane. A method for avoiding the creation of high edges at the electrodes (known as lift-off ears) is presented. The microchip design is highly symmetric to accommodate easy electronic integration and provides space for microfluidic inlets and outlets for integrated custom-made microfluidic systems on top.

Doped overoxidized polypyrrole microelectrodes as sensors for the detection of dopamine released from cell populations.

A surface modification of interdigitated gold microelectrodes (IDEs) with a doped polypyrrole (PPy) film for detection of dopamine released from populations of differentiated PC12 cells is presented. A thin PPy layer was potentiostatically electropolymerized from an aqueous pyrrole solution onto electrode surfaces. The conducting polymer film was doped during electropolymerization by introducing counter-ions in the monomer solution. Several counter-ions were tested and the resulting electrode modifications were characterized electrochemically to find the optimal dopant that increases sensitivity in dopamine detection. Overoxidation of the PPy films was shown to contribute to a significant enhancement in sensitivity to dopamine. The changes caused by overoxidation in the electrochemical behavior and electrode morphology were investigated using cyclic voltammetry and SEM as well as AFM, respectively. The optimal dopant for dopamine detection was found to be polystyrene sulfonate anion (PSS(-)). Rat pheochromocytoma (PC12) cells, a suitable model to study exocytotic dopamine release, were differentiated on IDEs functionalized with an overoxidized PSS(-)-doped PPy film. The modified electrodes were used to amperometrically detect dopamine released by populations of cells upon triggering cellular exocytosis with an elevated K(+) concentration. A comparison between the generated current on bare gold electrodes and gold electrodes modified with overoxidized doped PPy illustrates the clear advantage of the modification, yielding 2.6-fold signal amplification. The results also illustrate how to use cell population based dopamine exocytosis measurements to obtain biologically significant information that can be relevant in, for instance, the study of neural stem cell differentiation into dopaminergic neurons.

Hospital discharge: testing the "Blaylock Risk Assessment Screening Score" in a surgical department.

Background and aim of the work Standardizing patients' assessment to identify individuals at greater risk in encountering difficulties at discharge may help to assist healthcare professionals in clinical decision making and address the gaps in quality that negatively affect continuity of care. We analyzed the predictive validity and the test-retest reliability of the BRASS index in surgical inpatients. Moreover, we evaluated the association between other variables and length of stay or location at discharge. Methods A prospective observational study was conducted. Four hundred twenty-eight patients (≥18 years old) hospitalized in the surgical department of Vimercate hospital were recruited. Data were collected using BRASS index within 48 hours from admission and before discharge. Results We found a high specificity for BRASS in identifying patients discharged to their home with assistance or to residential care. The hospital stay for medium and high-risk patients was significantly longer than those in the low-risk group. There was no statistically significant difference of the BRASS scores during hospitalization. Type of admission, pressure ulcers, ASA score, multidrug-resistant bacterial infections, medical complications and Intensive Unit Care stay showed a significant correlation with longer hospitalization and increased probability to be discharged to their home with assistance or to residential care. Conclusions The BRASS Index may support healthcare professionals to identify surgical inpatients requiring a discharge planning and needs to be completed just once at admission. The inclusion of other patient-specific factors in the assessment process could be valuable for targeting the at-risk population.

[The assessment of planned discharges: agreement between BRASS index and clinical judgement]. / Valutazione delle dimissioni pianificate: concordanza tra indice di BRASS e giudizio clinico.

. The assessment of planned discharges: agreement between BRASS index and clinical judgement. INTRODUCTION: The BRASS (Blaylock Risk Assessment Screening Score) index is a risk screening tool for identification of patients at risk of difficult discharge. OBJECTIVE: To assess the agreement of discharge options between the BRASS classification and the nurses' clinical judgement. METHODS: Consecutive patients admitted to surgical wards of a large Italian hospital from November 2016 to June 2017 were assessed with the BRASS index within 48 hours from admission and 24 hours before discharge. After discharge a group of expert nurses, blind to the BRASS score and patient effective destination, planned the patients' discharge reviewing the clinical records. Patients were classified as needing ordinary discharge, with support or to hospital. RESULTS: The 90% of the 428 included patients remained in the same BRASS risk class; the agreement between BRASS score (K Cohen) at admission and clinical judgement was 0.474 and 0.533 at discharge. Of the 96 subject at need of discharge with support or to hospital, 60 were classified in the same class by the BRASS Index. Factors that impacted on the different classification were patients' age, presence of devices and availability and appropriateness of social support. CONCLUSIONS: Most patients remained in the same BRASS class. There is moderate agreement between BRASS index and clinical judgement, specifically for patients at medium/high risk of difficult discharge. Our data confirm the need for including new items in the Brass scale.

The role of micro-scale current sensing in biomedicine: A unifying view and design guidelines.

The electrical activity of cells is regulated by ion fluxes and chemical signaling between them is sustained by redox-reactive molecules. Consequently, current sensing represents a straightforward way to interface electronics with biology and a common detection tool in several applications spanning from patch-clamp and nanopores to micro-scale impedance tracking. Reaching pA resolution at the ms timescale represents a challenge for the readout circuit and here all the criticalities involved in the optimal design of the sensing electrode are reviewed. Advantages vs. drawbacks and risks of the use of silicon as active vs. passive substrate respectively are illustrated by means of experimental examples.

Multichannel bipotentiostat integrated with a microfluidic platform for electrochemical real-time monitoring of cell cultures.

An electrochemical detection system specifically designed for multi-parameter real-time monitoring of stem cell culturing/differentiation in a microfluidic system is presented. It is composed of a very compact 24-channel electronic board, compatible with arrays of microelectrodes and coupled to a microfluidic cell culture system. A versatile data acquisition software enables performing amperometry, cyclic voltammetry and impedance spectroscopy in each of the 12 independent chambers over a 100 kHz bandwidth with current resolution down to 5 pA for 100 ms measuring time. The design of the platform, its realization and experimental characterization are reported, with emphasis on the analysis of impact of input capacitance (i.e., microelectrode size) and microfluidic pump operation on current noise. Programmable sequences of successive injections of analytes (ferricyanide and dopamine) and rinsing buffer solution as well as the impedimetric continuous tracking for seven days of the proliferation of a colony of PC12 cells are successfully demonstrated.

Biosensors and molecular imaging.

The increase in the understanding of the physical and functional properties of the biological material, from the cellular level down to single molecules, owes its success to the development of suitable high-sensitivity platforms to image the biomaterial and analyze its response to specific stimuli. Imaging has indeed reached molecular capabilities, thanks to optical or magnetic markers [1], to the atomic force microscopy (AFM) in surface reconstruction [2], and is nearing success in three-dimensional (3-D) reconstruction thanks to X-ray holography [3].