Colorimetric sensor based on bubble wrap and camera phone for glucose determination

Thread- and Capillary Tube-Based Electrodes for the Detection of Glucose and Acetylthiocholine

An electrochemical sensor for the detection of glucose and acetylthiocholine (ATC) using thread- and capillary tube-based electrodes is described. Three nylon thread-based electrodes were fabricated by painting pieces of trifurcated nylon thread with conductive inks and threading the electrodes into capillary tubes. Two platforms, one paper-based and the other utilizing bubble wrap, were examined. For the glucose detection, a solution containing glucose oxidase (GOx), potassium ferricyanide (K3[Fe(CN)6]), and increasing concentrations of glucose (0-20 mM) in phosphate-buffered saline (PBS) was spotted onto the two platforms. Similarly, increasing concentrations of ATC (0-9.84 mg/mL) in acetylcholinesterase (AChE) (0.08 U/mL) and PBS solution were detected. Using cyclic voltammetry (CV), a scanning voltage was applied to yield a graph of voltage applied (V) vs. current output (A). For both platforms, both glucose and ATC concentrations were observed to be linearly proportional to the current output as demonstrated by the increased height of the oxidation peaks. The three-electrode system was simple to fabricate, inexpensive, and could be used for multiple readings.

Colorimetric hand-held sensors and biosensors with a small digital camera as signal recorder, a review

Sensors, biosensors, lateral flow immunoassays, portable thin-layer chromatography and similar devices for hand-held assay are tools suitable for field or out of laboratories assays of various analytes. The assays frequently exert a limit of detection and sensitivity close to more expensive and elaborative analytical methods. In recent years, huge progress has been made in the field of optical instruments where digital cameras or light sensitive chips serve for the measurement of color density. General availability of cameras, a decrease of prices and their integration into wide spectrum phones, tablets and computers give the promise of easy application of analytical methods where such cameras will be employed. This review summarizes research on hand-held assays where small cameras like the ones integrated into smartphones are used. Discussion about such assays, their practical applicability and relevant specifications are also written here.

A glassware-free combinatorial synthesis of green quantum dots using bubble wrap

Here, we describe the use of commercially-available bubble wrap as the basis for the simple, cheap combinatorial exploration of the synthesis of brightly emitting core/shell quantum dots.

In this communication, we highlight the use of bubble wrap in the simple parallel synthesis of CuInS₂-based quantum dots with different optical properties, based on varying precursors concentrations.