Recent Advances in Nanotechnology Applied to Biosensors

In recent years there has been great progress the application of nanomaterials in biosensors. The importance of these to the fundamental development of biosensors has been recognized. In particular, nanomaterials such as gold nanoparticles, carbon nanotubes, magnetic nanoparticles and quantum dots have been being actively investigated for their applications in biosensors, which have become a new interdisciplinary frontier between biological detection and material science. Here we review some of the main advances in this field over the past few years, explore the application prospects, and discuss the issues, approaches, and challenges, with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination

Synthesis and characterisation of doxorubicin-loaded functionalised cobalt ferrite nanoparticles and their in vitro anti-tumour activity under an AC-magnetic field

Purpose: To synthesise and evaluate the anti-tumour properties of doxorubicin-loaded xanthan gumfunctionalised cobalt ferrite nanoparticles (CoFe2O4.NPs@XG-Doxo) under an AC-magnetic field.Methods: Multidimensional magnetic cobalt ferrite (CoFe2O4) nanoparticles (NPs) were synthesised by a co-precipitation method. The synthesised cobalt ferrite nanoparticles (CFNPs) were functionalised with xanthine gum (XG) and subsequently characterised by Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and contact angle studies. Vibrating sample magnetometry (VSM) was used for magnetic measurements of the native and XG-coated CFNPs. The microstructural morphology of the uncoated and XG-coated CFNPs was established using scanning electron microscopy (SEM), atomic force microscopy (AFM) and dynamic light scattering (DLS) studies. Finally, the doxorubicin release profile of the drug-loaded functionalised CFNPs was evaluated using an oscillating magnetic field (OMF) apparatus in the presence of an externally applied magnetic field.Results: XG coating decreased the contact angle of the native CFNPs from 92° to 40°, which indicates that it modified the CFNP surface from hydrophobic to hydrophilic. VSM analysis demonstrated that CoFe2O4.NPs@XG also retained the magnetic characteristics of the bare cobalt ferrite nanocrystals, endorsing its application as a promising magnetic nanovector (MNV). The synthesised CoFe2O4.NPs@XG-Doxo exhibited significantly higher controlled discharge of doxorubicin at acidic pH (5.0) than at neutral pH (7.4). In vitro analysis revealed the remarkable lower systematic toxicity of XGcoated CoFe2O4.NPs compared with uncoated CFNPs against Chinese hamster ovary (CHO) and Huh7 cell lines.Conclusion: These results indicate that XG-coated CFNPs are a biocompatible MNV for doxorubicin.Keywords: Cobalt ferrite, Cytotoxicity, Drug delivery, Nanoparticles, Xanthan gu

Electrochemical biosensors and nanobiosensors

Electrochemical techniques have great promise for low-cost, miniaturised, easy-to-use, portable devices for a wide range of applications – in particular medical diagnosis and environmental monitoring. Different techniques can be used for biosensing, with amperometric devices taking the central role due to their widespread application in glucose monitoring. In fact, glucose biosensing takes a share of around 70% of the biosensor market due to the need for diabetic patients to monitor their sugar levels several times a day, making it an appealing commercial market.In this chapter we present the basic principles of electrochemical biosensor devices. A description of the different generations of glucose sensors is used to describe in some detail the operation of amperometric sensors and how the introduction of mediators can enhance the performance of the sensors. Electrochemical impedance spectroscopy is a technique being increasingly used in devices due to its ability to detect variations in resistance and capacitance upon binding events. Novel advances in electrochemical sensors due to the use of nanomaterials such as carbon nanotubes and graphene are presented as well as well as future directions that the field is taking.<br/

PHOTOLUMINESCENCE SPECTROSCOPIC STUDIES OF MN2O3/CO3O4-GLUCOSE/LACTOSE COMPLEXES

As nanoparticles serve as mediators in the electron transfer between biomolecules and a biosensor’s electrode surface, this study is dedicated to investigating Mn2O3 and Co3O4 nanoparticles and their photoluminescence effect that play a critical role in sensing glucose and lactose. The chemical coprecipitation method was adopted for preparing the nanoparticles that were characterized by X-Ray Diffraction, Transmission Electron Microscope, Fourier Transform Infrared spectroscopy, Energy Dispersive X-ray, UV-vis spectroscopy, and Vibrating Sample Magnetometry. It was found that the obtained Mn2O3 and Co3O4 nanoparticles were successfully prepared, with a crystallite size of 65.91 and 58.00 nm, respectively. The high specific surface area of 1.2808´104 and 0.5711´104 m2/kg was noticed for the Mn2O3 and Co3O4 nanoparticles that exhibited highly agglomerated cubic and spherical nanoparticles, respectively. The energy gap, Urbach energy, and steepness parameter were obtained (1.72 eV, 1.049 eV and 24.644´10-3 for Mn2O3 and 1.285/2.165 eV, 2.893 eV and 8.936´10-3 for Co3O4) and discussed. Antiferromagnetism and weak ferromagnetism were detected for Mn2O3 and Co3O4 nanoparticles, respectively, with higher saturation magnetization for Mn2O3 (2.435 emu/g). Moreover, the non-enzymatic glucose and lactose biosensor’s compatibility was evaluated utilizing photoluminescence changes. The glucose/lactose interactions with Mn2O3 /Co3O4 nanoparticles were measured by photoluminescence spectroscopy, at room temperature, in a phosphate buffer medium. The addition of Mn2O3 nanoparticles to glucose and lactose demonstrated higher shifts in the photoluminescence intensities with larger binding constants (1625 and 1840 M-1) and more negative Gibbs energy (-17.608 and -18.753 kJ.mol-1). These characteristics promote the investigation of Mn2O3 nanoparticles in glucose and lactose biosensors

Tiny Medicine: Nanomaterial-Based Biosensors

Tiny medicine refers to the development of small easy to use devices that can help in the early diagnosis and treatment of disease. Early diagnosis is the key to successfully treating many diseases. Nanomaterial-based biosensors utilize the unique properties of biological and physical nanomaterials to recognize a target molecule and effect transduction of an electronic signal. In general, the advantages of nanomaterial-based biosensors are fast response, small size, high sensitivity, and portability compared to existing large electrodes and sensors. Systems integration is the core technology that enables tiny medicine. Integration of nanomaterials, microfluidics, automatic samplers, and transduction devices on a single chip provides many advantages for point of care devices such as biosensors. Biosensors are also being used as new analytical tools to study medicine. Thus this paper reviews how nanomaterials can be used to build biosensors and how these biosensors can help now and in the future to detect disease and monitor therapies

Biomarker Discovery by Novel Sensors Based on Nanoproteomics Approaches

During the last years, proteomics has facilitated biomarker discovery by coupling high-throughput techniques with novel nanosensors. In the present review, we focus on the study of label-based and label-free detection systems, as well as nanotechnology approaches, indicating their advantages and applications in biomarker discovery. In addition, several disease biomarkers are shown in order to display the clinical importance of the improvement of sensitivity and selectivity by using nanoproteomics approaches as novel sensors

Nanotechnology for Early Cancer Detection

Vast numbers of studies and developments in the nanotechnology area have been conducted and many nanomaterials have been utilized to detect cancers at early stages. Nanomaterials have unique physical, optical and electrical properties that have proven to be very useful in sensing. Quantum dots, gold nanoparticles, magnetic nanoparticles, carbon nanotubes, gold nanowires and many other materials have been developed over the years, alongside the discovery of a wide range of biomarkers to lower the detection limit of cancer biomarkers. Proteins, antibody fragments, DNA fragments, and RNA fragments are the base of cancer biomarkers and have been used as targets in cancer detection and monitoring. It is highly anticipated that in the near future, we might be able to detect cancer at a very early stage, providing a much higher chance of treatment

Electrochemical biosensors and nanobiosensors

Electrochemical techniques have great promise for low-cost miniaturised easy-to-use portable devices for a wide range of applications–in particular, medical diagnosis and environmental monitoring. Different techniques can be used for biosensing, with amperometric devices taking the central role due to their widespread application in glucose monitoring. In fact, glucose biosensing takes an approximately 70% share of the biosensor market due to the need for diabetic patients to monitor their sugar levels several times a day, making it an appealing commercial market. In this review, we present the basic principles of electrochemical biosensor devices. A description of the different generations of glucose sensors is used to describe in some detail the operation of amperometric sensors and how the introduction of mediators can enhance the performance of the sensors. Electrochemical impedance spectroscopy is a technique being increasingly used in devices due to its ability to detect variations in resistance and capacitance upon binding events. Novel advances in electrochemical sensors, due to the use of nanomaterials such as carbon nanotubes and graphene, are presented as well as future directions that the field is taking