Delivering Inorganic and Organic Reagents and Enzymes from Zein and Developing Optical Sensors

Abstract

Nowadays, interest in using environmentally friendly materials is increasing in many fields. However, the rational design of sensors with biodegradable materials is a challenge. The main aim of this work is to show the possibility of using zein, a protein from corn, as a biodegradable and low-cost material for immobilizing, stabilizing, and delivering different kind of reagents for developing optical sensors. Enzymes, metallic salts, and aromatic and small organic compounds were tested. In addition, different techniques of immobilization, entrapment and adsorption, were used, and different formats, such as solid devices and also multiwell platforms, were proposed. The capacity of zein for immobilizing two reagents together, enzyme and substrate, into a multianalysis format was also shown. Two applications were developed as examples: a colorimetric assay based on a ferric hydroxamate reaction for ester drugs, which was applied in atropine determination in pills, and a fluorimetric enzymatic multiwell-plate biodevice applied in phosphate determination in human serum and urine. Zein demonstrated being not only a green alternative but also a versatile polymer for developing sensors from reagents with different natures in different formats and matrices, thereby resulting in different applications.

Advances in the Measurement of Polymeric Colorimetric Sensors Using Portable Instrumentation: Testing the Light Influence

“…Digitalized images can also be processed by external programs, such as GIMP, imageJ or MATLAB. As can be seen in previous studies, the processing of images can improve the results obtained, achieving higher linearity and sensitivity [ 2 ]. In the last decade, digital cameras and smartphones facilitated the emergence and development of new devices for color analysis at more affordable prices [ 11 , 18 ].…”

“…One option proposed to address this challenge is to use sensors combined with portable instrumentation [ 1 ]. In this context, Campíns-Falcó et al proposed the use of polymers as supporting materials to embed chromogenic [ 1 ] or fluorescent [ 2 ] reagents. Between these materials, polydimethyl siloxane (PDMS) stands out.…”

Luminol Doped Silica-Polymer Sensor for Portable Organic Amino Nitrogen and Ammonium Determination in Water

“…To check the best material to immobilize and after to release luminol to the solution, different supports were tested. Based on our experience [1,[19][20][21][22], several solid supports for luminol entrapment were studied: PDMS, zein, and TEOS/MTEOS. Solid supports of PDMS (Figure 4A,B) or PDMS-TEOS (Figure 4C-E) containing luminol were synthetized.…”

Improving Sustainability of the Griess Reaction by Reagent Stabilization on PDMS Membranes and ZnNPs as Reductor of Nitrates: Application to Different Water Samples

“…Concerning to Griess reagents, these are rather unstable and usually need to be keeping at low temperatures as individual solutions. One option to stabilize reagents is to embed them in solid supports; materials such as polymers can be used as an inert matrix support [ 13 , 14 ]. This approach is being used for the development of optical sensors and microfluidic devices [ 15 , 16 , 17 , 18 ].…”