The Takeover of Standardized Tests

Diane Ravitch once said, “Sometimes the most brilliant and intelligent students do not shine in standardized tests because they do not have standardized minds”. Standardized testing is a very controversial issue occurring in our school systems today. Standards hold schools and teachers accountable for properly progressing our youth through school. However, is administering the same exact test to every child in every school district the best way to measure growth? There are many factors that makes up a school and student body such as poverty, cultural beliefs etc. These factors are not addressed in the standardized tests that our students take year in and year out. Throughout this research paper, there are many options explored to replace standardized tests, survey results from a local school district’s students pertaining to their opinions of the test, and other issues caused from the tests. There is no set answer as to if these tests will be going away any time soon, however many educators, parents and community members are beginning to take steps to ensure there are no more standardized tests

Monitoring Reversible Tight Junction Modulation with a Current‐Driven Organic Electrochemical Transistor

AbstractThe barrier functionality of a cell layer regulates the passage of nutrients into the blood. Modulating the barrier functionality by external chemical agents like poly‐l‐lysine (PLL) is crucial for drug delivery. The ability of a cell layer to impede the passage of ions through it and therefore to act as a barrier, can be assessed electrically by measuring the resistance across the cell layer. Here, an organic electrochemical transistor (OECT) is used in a current‐driven configuration for the evaluation of reversible modulation of tight junctions in Caco‐2 cells over time. Exposure to low and medium concentrations of PLL initiates reversible modulation, whereas a too high concentration induces an irreversible barrier disruption due to nonfunctional tight junction proteins. The results demonstrate the suitability of OECTs to in situ monitor temporal barrier modulation and recovery, which can offer valuable information for drug delivery applications

Current-Driven Organic Electrochemical Transistors for Monitoring Cell Layer Integrity with Enhanced Sensitivity

AbstractIn this progress report an overview is given on the use of the organic electrochemical transistor (OECT) as a biosensor for impedance sensing of cell layers. The transient OECT current can be used to detect changes in the impedance of the cell layer, as shown by Jimison et al. To circumvent the application of a high gate bias and preventing electrolysis of the electrolyte, in case of small impedance variations, an alternative measuring technique based on an OECT in a current‐driven configuration is developed. The ion‐sensitivity is larger than 1200 mV V‐1dec‐1 at low operating voltage. It can be even further enhanced using an OECT based complementary amplifier, which consists of a p‐type and an n‐type OECT connected in series, as known from digital electronics. The monitoring of cell layer integrity and irreversible disruption of barrier function with the current‐driven OECT is demonstrated for an epithelial Caco‐2 cell layer, showing the enhanced ion‐sensitivity as compared to the standard OECT configuration. As a state‐of‐the‐art application of the current‐driven OECT, the in situ monitoring of reversible tight junction modulation under the effect of drug additives, like poly‐l‐lysine, is discussed. This shows its potential for in vitro and even in vivo toxicological and drug delivery studies

Monitoring Reversible Tight Junction Modulation with a Current-Driven Organic Electrochemical Transistor

The barrier functionality of a cell layer regulates the passage of nutrients into the blood. Modulating the barrier functionality by external chemical agents like poly-l-lysine (PLL) is crucial for drug delivery. The ability of a cell layer to impede the passage of ions through it and therefore to act as a barrier, can be assessed electrically by measuring the resistance across the cell layer. Here, an organic electrochemical transistor (OECT) is used in a current-driven configuration for the evaluation of reversible modulation of tight junctions in Caco-2 cells over time. Exposure to low and medium concentrations of PLL initiates reversible modulation, whereas a too high concentration induces an irreversible barrier disruption due to nonfunctional tight junction proteins. The results demonstrate the suitability of OECTs to in situ monitor temporal barrier modulation and recovery, which can offer valuable information for drug delivery applications

Selective Ion Detection with Integrated Organic Electrochemical Transistors

Accurate sensing of ion concentrations in body fluids is of importance to monitor cell functions, and any deviation of the concentration serves as a warning sign of pathophysiological conditions. Here, a fabrication approach for an integrated device consisting of two electrochemical transistors, capable of selective simultaneous detection between potassium and sodium ions in an analyte is demonstrated. A common in-plane gate electrode is integrated in the substrate, enabling the fabrication of micro-scale ion sensors for biomedical applications. The approach is versatile and can be extended to include numerous ion-selective transistors on a chip in order to meet the demand for simultaneous sensing of multiple ions

Integrated amplifier with complementary organic electrochemical transistors for high-sensitivity ion detection and real-time monitoring

Ions are fundamental biological regulators enabling the communication between cells, regulating metabolic and bioenergetic processing and playing a key role in pH regulation and hydration. The in-situ quantification of the ion concentration is gathering relevant interest in biomedical diagnostics and healthcare. State-of-art transistor-based ion sensors show an intrinsic trade-off between sensitivity, operating range and supply voltage. To overcome these limitations, here we focus on ion sensor amplifiers where complementary OECTs are integrated in a push-pull configuration, providing sensitivity larger than 1 V/dec at a supply voltage down to 0.5 V and operating in the physiological range. Ion detection over a range of five orders of magnitude and real-time monitoring of variations two orders of magnitude lower than the detected concentration are achieved. The ion-sensitive amplifier sets a new benchmark for ion-sensing devices, opening possibilities for predictive diagnostics and personalized medicine

Multiscale real time and high sensitivity ion detection with complementary organic electrochemical transistors amplifier

Though organic electrochemical transistor (OECT)-based ion sensors are attractive for highly sensitive ion detection and monitoring, its limited sensitivity hinders its practical applicability. Here, the authors report real-time, high sensitivity ion detection with complementary OECT amplifiers