Electrochemical biosensors combine the sensitivity of electroanalytical methods with the inherent bioselectivity of the biological component. The biological component in the sensor recognizes its analyte resulting in a catalytic or binding event that ultimately produces an electrical signal monitored by a transducer that is proportional to analyte concentration. Some of these sensor devices have reached the commercial stage and are routinely used in clinical, environmental, industrial, and agricultural applications. The two classes of electrochemical biosensors, biocatalytic devices and affinity sensors, will be discussed in this critical review to provide an accessible introduction to electrochemical biosensors for any scientist (110 references).

The evolution of 1st to 3rd generation electrochemical biosensors reflects a simplification and enhancement of the transduction pathway. However, in recent years, modification of the transducer with nanomaterials has become increasingly studied and imparts many advantages. The sensitivity and overall performance of enzymatic biosensors has improved tremendously as a result of incorporating nanomaterials in their fabrication. Given the unique and favorable qualities of gold nanoparticles, graphene and carbon nanotubes as applied to electrochemical biosensors, a consolidated survey of the different methods of nanomaterial immobilization on transducer surfaces and enzyme immobilization on these species is beneficial and timely. This review encompasses modification of enzymatic biosensors with gold nanoparticles, carbon nanotubes, and graphene.

Nanotechnology has played a crucial role in the development of biosensors over the past decade. The development, testing, optimization, and validation of new biosensors has become a highly interdisciplinary effort involving experts in chemistry, biology, physics, engineering, and medicine. The sensitivity, the specificity and the reproducibility of biosensors have improved tremendously as a result of incorporating nanomaterials in their design. In general, nanomaterials-based electrochemical immunosensors amplify the sensitivity by facilitating greater loading of the larger sensing surface with biorecognition molecules as well as improving the electrochemical properties of the transducer. The most common types of nanomaterials and their properties will be described. In addition, the utilization of nanomaterials in immunosensors for biomarker detection will be discussed since these biosensors have enormous potential for a myriad of clinical uses. Electrochemical immunosensors provide a specific and simple analytical alternative as evidenced by their brief analysis times, inexpensive instrumentation, lower assay cost as well as good portability and amenability to miniaturization. The role nanomaterials play in biosensors, their ability to improve detection capabilities in low concentration analytes yielding clinically useful data and their impact on other biosensor performance properties will be discussed. Finally, the most common types of electroanalytical detection methods will be briefly touched upon.

Glutamate, a major excitatory neurotransmitter in the mammalian central nervous system, plays a vital role in many physiological processes and is one of the key neurotransmitters of interest in psychopharmacology. It is involved in many normal and abnormal behaviors related to neurological and psychiatric disorders. The glutamate system has been proposed to play a significant role in various neurological and psychiatric disorders such as Alzheimer's disease, autism, schizophrenia, depression, drug addiction, and more. The design, construction, and optimization of enzyme-based electrochemical biosensors for in vivo and in vitro detection of glutamate are active areas of interdisciplinary research. For example, various glutamate biosensors have been developed for monitoring dynamic levels of extracellular glutamate in the living brain tissue adding to the current medical knowledge of these complex neurotransmitter systems and ultimately impacting treatment plans. In addition to biological sciences and clinical medicine, glutamate biosensors have been used in environmental monitoring, in the fermentation industry, and in the food industry for determination of monosodium glutamate (MSG), a common flavor-enhancing food additive.

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Review: 110 refs.

Studies have shown that the more ownership students take of their academic work, the greater the level of information retained, knowledge acquired, and general cognitive development.Many teaching techniques that span across sciences, and go beyond standard techniques such as: merely lecturing at students or following written procedures for "cook book-style" laboratory experiments, have surfaced in the last decade. One such method, known as Course Preparation Assignments (CPAs), requires students to read and analyze course material prior to attending class.This approach gives students their first exposure to new content outside of the classroom, while also engaging them in responding to a series of questions that they must answer individually. This prior exposure to course material allows the students to not only complete written assignments with the incentive of earning points, but also forces them to reflect on what they are learning. Prior to adopting the CPA teaching practice, I discovered that very few of my chemistry and biochemistry students completed the reading and homework problems until a few days prior to an examination. Each class or unit that includes a CPA follows a predictable pattern which students adjust to quickly: Read -Think -Write/Draw/Calculate -Discuss the course content. The impact of incorporating CPAs into undergraduate Analytical Chemistry and Principles of Biochemistry lecture courses will be described from this instructor's point of view. In addition, the advantages and challenges of utilizing this teaching approach at a Primarily Undergraduate Institution, within classes made up of 8-45 students, will be described. Furthermore, the development and use of CPAs for teaching various Chemistry courses, the leading and facilitating of course discussions in class, the grading of assignments, and student perceptions of the approach will be discussed. Indeed, the pedagogical approach generally promotes timely completion of assignments, helps create a more interactive classroom setting, encourages students to ask more questions, facilitates involvement in discussions all of which result in an improved ability to think and reason critically.

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