Magnetite-Based Biosensors and Molecular Logic Gates: From Magnetite Synthesis to Application

Abstract

In the last few decades, point-of-care (POC) sensors have become increasingly important in the detection of various targets for the early diagnostics and treatment of diseases. Diverse nanomaterials are used as building blocks for the development of smart biosensors and magnetite nanoparticles (MNPs) are among them. The intrinsic properties of MNPs, such as their large surface area, chemical stability, ease of functionalization, high saturation magnetization, and more, mean they have great potential for use in biosensors. Moreover, the unique characteristics of MNPs, such as their response to external magnetic fields, allow them to be easily manipulated (concentrated and redispersed) in fluidic media. As they are functionalized with biomolecules, MNPs bear high sensitivity and selectivity towards the detection of target biomolecules, which means they are advantageous in biosensor development and lead to a more sensitive, rapid, and accurate identification and quantification of target analytes. Due to the abovementioned properties of functionalized MNPs and their unique magnetic characteristics, they could be employed in the creation of new POC devices, molecular logic gates, and new biomolecular-based biocomputing interfaces, which would build on new ideas and principles. The current review outlines the synthesis, surface coverage, and functionalization of MNPs, as well as recent advancements in magnetite-based biosensors for POC diagnostics and some perspectives in molecular logic, and it also contains some of our own results regarding the topic, which include synthetic MNPs, their application for sample preparation, and the design of fluorescent-based molecular logic gates.

Synthesis of Iron Oxides and Influence on Final Sizes and Distribution in Bacterial Cellulose Applications

“…Industrially, iron oxides and oxyhydroxides are present in the extraction of metallic iron, the production of dyes due to the diversity of colours, the fabrication of magnetic alloys for magnets, etc. Iron oxide nanoparticles are used in different applications, mainly due to their magnetic characteristics, such as electronic devices, inductors, solar cells, water treatment processes, the immobilisation of enzymes, sound amplification equipment, data storage systems, sensors and medical treatment systems (such as hyperthermia, cancer therapy and drug delivery systems) [ 5 , 8 , 9 , 21 , 22 ]. However, the obtainment of iron oxide nanoparticles and SPIONs can be quite challenging, as each of the different obtainment methods has advantages and disadvantages that exert an impact on the characteristics of the end product [ 7 , 23 ].…”

“…The use of magnetic particles as transducers is common in sensors. In the case of blood glucose biosensors, however, magnetite can be used as a synthetic enzyme and as a Fenton reagent due to the presence of Fe 2+ , which can mimic the action of the enzyme peroxidase (which is present in the reactive strips of the sensor) [ 9 ].…”

“…In such applications, the control of the size distribution is essential, as very large particles can interfere with the action of SPIONs. In contrast, nanoparticles can have larger sizes in applications that require materials with ferromagnetic properties, in which the control over the size uniformity is less rigorous [ 9 ].…”

Metal Nanoparticles as Novel Drug Delivery Systems: A Review of Current Challenges and Opportunities

“…The produced MNPs have a wide range of applications in various fields, including biomedicine, environmental remediation, and energy. As shown in Figure 5, the use of microorganisms and plants as a starting point for the production of different metallic nanoparticles, such as silver, gold, palladium, copper, and metal compounds, holds great potential as a method that is both kind to the environment and economical [86].…”