Despite the existence of some disputes, this technology renders immense hope for the future. It may lead to inno- vations by playing a prominent role in various biomedical applications ranging from drug delivery and gene therapy to molecular imaging, biomarkers and biosensors. One of these applications being the prime research objective of the present time would be target-specific drug therapy and methods for early diagnosis and treatment of diseases . Two types of medical applications are already emerging, both in clinical diagnosis and in R&D. Imaging applications, such as quantum dot technology are already being licensed and applications for monitoring cellular activities in tissue are coming soon. The second major type of application involves the development of highly specific and sensitive means of detecting nucleic acids and proteins . By 2015 to 2020, we will see that products being tested in academic and government laboratories will be creeping into commercialization. Sparse cell isolation and molecular fil- tration applications should, by then, make it to market. Some of the drug delivery systems should be commercialized or in advanced clinical trials. For ex- ample - drug delivery systems have been developed by NanoSystems or by American Pharmaceutical Partners, which is testing the encapsulation of Taxol, a cancer drug in a nanopolymer called paclitaxel. Most medical devices and therapeutics are a decade or more away from mar- ket. Therefore, drug target manipulation as well as device implantation requires a complex technical infrastructure like nanotechnology as well as complex regulatory man- agement .
Abstract: Foodborne disease is an important source of expense, morbidity, and mortality for society. Detection and control constitute significant components of the overall management of foodborne bacterial pathogens, and this review focuses on the use of nanosized biological entities and molecules to achieve these goals. There is an emphasis on the use of organisms called bacteriophages (phages: viruses that infect bacteria), which are increasingly being used in pathogen detection and biocontrol applications. Detection of pathogens in foods by con- ventional techniques is time-consuming and expensive, although it can also be sensitive and accurate. Nanobiotechnology is being used to decrease detection times and cost through the development of biosensors, exploiting specific cell-recognition properties of antibodies and phage proteins. Although sensitivity per test can be excellent (eg, the detection of one cell), the very small volumes tested mean that sensitivity per sample is less compelling. An ideal detection method needs to be inexpensive, sensitive, and accurate, but no approach yet achieves all three. For nanobiotechnology to displace existing methods (culture-based, antibody-based rapid methods, or those that detect amplified nucleic acid) it will need to focus on improving sensitivity. Although manufactured nonbiological nanoparticles have been used to kill bacterial cells, nanosized organisms called phages are increasingly finding favor in food safety applica- tions. Phages are amenable to protein and nucleic acid labeling, and can be very specific, and the typical large “burst size” resulting from phage amplification can be harnessed to produce a rapid increase in signal to facilitate detection. There are now several commercially available phages for pathogen control, and many reports in the literature demonstrate efficacy against a number of foodborne pathogens on diverse foods. As a method for control of pathogens, nano- biotechnology is therefore flourishing.
Biosorbents: can be defined as the selective seques- tering of metal soluble species that result in the immobi- lization of the metals by microbial cells such as cyano- bacteria. It is the physicochemical mechanisms of inac- tive (i.e. non-metabolic) metal uptake by microbial bio- mass. Metal sequestering by different parts of the cell can occur via various processes: complexation, chelation, coordination, ion exchange, precipitation, reduction. Size of immobilized bead for metals removal is a crucial fac- tor for use of immobilized biomass in bio-sorption proc- ess. It is recommended that beads should be in the size range between 0.7 and 1.5 mm, corresponding to the size of commercial resins meant for removing metal ions. Abdel Hameed and Ebrahim, 2007  in their review article, has revealed some of the immobilized algae on different matrices that have potential in heavy metals removal due to its high uptake capacity and abundance. 2.9. Production of Biosensors
free, reagentless, real time monitoring, miniaturization and low cost application. For medical application, this cost advantage will allow the development of extremely low cost, disposable biochips that can be used for in-home medical diagnostics of diseases without the need of sending samples to a laboratory for analysis which time consuming. Hence biosensors offer an exciting alternative to traditional methods, allowing rapid “real-time” and multiple analyses for detection, diagnosis and estimation of any sample. For medical applications nanobiosensors, integrated biosensors and biochips will reduce the cost and time thereby increasing the efficiency of the tests. Also disposable biochips offer an added advantage of in-home medical diagnostics of diseases without the need of sending samples to a laboratory for analysis. In the past 40 years various biosensors have been researched and developed encompassing a wide range of applications but the number of commercially available biosensors is limited. Nevertheless, biosensor technology presents an opportunity for the development of robust, low cost, specific detection and analyses. Future prospects of biosensor technology, with special emphasis on the development of sensing elements and transducers are under current research.
Nanoengineered biosensors have altered the field of bio- medical engineering by introduction of smaller sensing structures for highly selective and sensitive detection of biomolecules . Nanomaterials of varied forms, includ- ing single or hybrids/combinatorial nanostructures, can be designed with distinctive features that are significantly different from conventional bulk materials. With smart engineering, nanomaterials functionalities and character- istics can be optimized to allow high selectivity binding properties for analyzing nanoscale elements of biomol- ecules. Additionally, the distinct molecular recognition interactions at the nano-realm level in combination with nanoscale components can further promote high sensi- tivity of the biosensors . Nanostructured metal oxides have received great attention for biosensing applications owing to several characteristics such as ease of fabrica- tion and controllable size/shape, biocompatibility, cata- lytic and optical properties, chemical stability, strong adsorption ability and electron-transfer kinetics . Zinc oxide (ZnO), an n-type semiconductor metal oxide with
Victoria has centres of expertise in nanotechnology in its universities and in CSIRO divisions. The strong medical and biotechnology research and commercialization activities provide the opportunity for significant interaction in the nanobiotechnology area. The Victorian Government has awarded A$12 million over three years from its Infrastructure Development Program to support the setting- up of Nano Vic, which draws together most of the major R&D groups of universities and of CSIRO in Victoria in a unified approach. The participants will provide cash and in-kind support approaching A$30 million over three years. Through a company structure, NanoVic will support four fundamental platforms – design and processing at the nanoscale, characterization of the performance of nanoscale systems, nanoscale structural characteristics, and modelling of nanosystems. These will be focused into three research programs - nanofabrication and characterization, chemical and biomolecular nanotechnology, and nanostructured materials. An aim is to create an Australian Centre for Molecular Nanotechnology and thus exploit opportunities in the health and pharmaceutical sector, and in the advanced manufacturing sector in Victoria.
Applications: Biosensors have many uses in clinical analysis, general health care monitoring, veterinary and agricultural applications, industrial processing and monitoring, and environmental pollution control. The advantages are likely to include low cost, small size, quick and easy use, as well as a sensitivity and selectivity greater than the current instruments. The advent of cheap, user-friendly biosensors will revolutionize the practice of healthcare monitoring and enables more in-depth diagnosis on a metabolic basis. The introduction of suitable biosensors would have considerable impact in the following areas. Clinical and Diagnostic Applications: Bench top biosensors of the electrochemical variety are used now in clinical biochemistry laboratories for measuring glucose and lactic acid 35 . A key feature of this is the ability for direct measurement on undiluted blood samples. Consumer self-testing, especially self-monitoring of blood components is another important area of clinical medicine and healthcare to be impacted by commercial biosensors. Current methods are based on colorimetric dry reagent chemistry often in conjunction with a portable reflectance meter. Biosensors offer the potential of reusable systems and other advantages by employing electrochemical detection rather than colour changes to help alleviate the problems of those with poor eyesight (some of them diabetics who are often heavy users of biosensors for glucose determination).
In order to improve immobilization process which is cru- cial for creating of high-performance biosensors, various techniques are used. In recent time, very often different types of nanoparticles become more popular for biosensor creation. One of these perspective nanomaterials is zeolite. Zeolites are hydrated microporous crystalline minerals. They are composed mainly of silicon, aluminum and oxygen. The modification of crystal structures makes it possible to obtain zeolites with different properties [1,2]. The regular microporous structure of the zeolite guaran- tees an improvement of the chemical and physical stabili- ties of the immobilized agent, whereas the porosity of the zeolite keeps open the access of the guest molecules or ions to the ambient. Furthermore, zeolites are able to exchange ions with some compounds. An important
phytohormones, an area of great potential for new biosensors. There are extremely useful biosensors for some signals, but most remain qualitative. Other qualities sought in biosensors are temporal and spatial resolution and, usually, an ability to use them without significantly perturbing the system. Currently, the biosensors with the best properties are the genetically-encoded optical biosensors based on FRET, but each sensor needs extensive specific effort to develop. Sensor technologies using antibodies as the recognition domain are more generic, but these tend to be more invasive and there are few examples of their use in plant biology. By capturing some of the opportunities appearing with advances in platform technologies it is hoped that more biosensors will become available to plant scientists.
https://doi.org/10.4236/ns.2019.118026 262 Natural Science July 2010 and September 2017. For experimental data of the same period, we previously published six pa- pers [1-6] on the function of the PS in which we discovered that “the PS and a human were related” and two papers [15, 16] on the characteristics of the biosensors. The red circles are summer data and the blue triangles are winter data. In Figure 2(a) summer data were the results obtained by experiments when the daytime was more than 12 hours. Summer was therefore from the day of the spring equinox to the day of the autumn equinox. The day of the spring equinox when not a leap year was March 20, and the value on the horizontal axis, 81. The day of the autumn equinox when not a leap year was September 23, and the value on the horizontal axis, 267. Analogously, winter data were the results obtained by experiments when the day length was less than 12 hours. The numbers of data were n = 252 for summer data and n = 216 for winter data.
electrochemical-biosensors is quite similar. The electrochemical-biosensors having electrodes and enzymatic catalysis produce an electrical voltage, where the physical interpretations of biological elements is possible by using methods of an electrical engineering. These analyses by the electrochemical biosensors are based on measuring of electrical voltage or currents, or inductances . It may be easily performed a test by measuring of the electromotive force in volts to analyze the concentration of biological elements. For some biosensors, the concept can be set at using optical-bio- elements, which are able to exhibit the changes in absorbance or fluorescence to detect any change through the biological elements. It is evident that biosensors have growing popularity in the number of applications. Their electrical characteristics are needed to set the semiconductor biosensors-devices in order to apply its internal effects to an electrical behavior versus biological elements. They are small physically a relatively inexpensive, for the most of the values required.
The need for rapid evaluation of chemicals in the environment or human body has prompted researchers to develop easy to use biological assays or biosensors. The new developments in light sensitive and conductive polymers integrated with micro-optics can monitor “practically anything” such as toxicity to DNA, life (cytotoxicity), endocrine disrupting chemicals or environmental pollutants. Such new generation biochips offer a panoramic view of once unthinkable diagnostics, propelling the laboratory into nanoscale dimensions.
used in the 1980’s for the production of enzyme electrodes and currently half of the disposable glucose electrodes are screen printed using curable polymer inks (Turner, 2013). While screen printing is capable of forming a biosensor with thick films, inkjet printing is capable of using very small quantities of enzyme reagents required for the fabrication of disposable biosensors with minimum waste and high reproducibility which lends itself well attractive in mass production of disposable biosensors (Delaney, Smith and Schubert, 2009). Drop-on-demand which is based on producing droplets when required, and continuous inkjet in which droplets are formed from a continuous stream to the substrate when needed, are two types of inkjet printing techniques. Droplets can be generated using piezoelectric, thermal and electrostatic techniques (Hutchings and Martin, 2013). Among them, drop-on- demand techniques capable of deposition of pico-litre to nano-litre size reagent containing proteins precisely to a designated sensor area with minimum waste were found to be more suitable for fabrication of disposable biosensors and point of care diagnostic products (Delaney, Smith and Schubert, 2009).
Bilayer lipid membranes (BLMs) can be successfully formed on polymers electrodeposited on a solid metallic support. Avidin–biotin interactions were employed for immobilisation of the enzyme on the surface of the BLM. Improved long-term stability and better selectivity towards certain interfering electroactive species were observed for a BLM glucose biosensor based on glucose oxidase immobilised on a platinum support modified with any of several polymers . However, the best results were obtained for the mediated system in which the BLM was formed on a Pt support covered with a layer of evaporated Nafion with incorporated ferrocene. The stable and sensitive response with significant elimination of the influence of electroactive interferences on the signal magnitude should allow a practical application of such miniaturised biosensors.
Abstract: Owing to peculiar properties of nanobody, including nanoscale size, robust structure, stable and soluble behaviors in aqueous solution, reversible refolding, high affinity and specificity for only one cognate target, superior cryptic cleft accessibility, and deep tissue penetration, as well as a sustainable source, it has been an ideal research tool for the development of sophisticated nanobiotechnologies. Currently, the nanobody has been evolved into versatile research and application tool kits for diverse biomedical and biotechnology applications. Vari- ous nanobody-derived formats, including the nanobody itself, the radionuclide or fluorescent- labeled nanobodies, nanobody homo- or heteromultimers, nanobody-coated nanoparticles, and nanobody-displayed bacteriophages, have been successfully demonstrated as powerful nanobiotechnological tool kits for basic biomedical research, targeting drug delivery and therapy, disease diagnosis, bioimaging, and agricultural and plant protection. These applications indicate a special advantage of these nanobody-derived technologies, already surpassing the “me-too” products of other equivalent binders, such as the full-length antibodies, single-chain variable fragments, antigen-binding fragments, targeting peptides, and DNA-based aptamers. In this review, we summarize the current state of the art in nanobody research, focusing on the nanobody structural features, nanobody production approach, nanobody-derived nanobiotech- nology tool kits, and the potentially diverse applications in biomedicine and biotechnology. The future trends, challenges, and limitations of the nanobody-derived nanobiotechnology tool kits are also discussed.
To test whether natural bacterial communities can be used as more-general geochemical biosensors, we expanded our model- ing efforts beyond contamination classification to predict the values for 38 geochemical parameters measured at each site. High- lighting the flexibility of our approach, we predicted the quanti- tative values of each parameter at each well rather than classifying the values into discrete categories. As expected given its important role in cell physiology, we found that 16S rRNA can be used to predict pH, recovering spatial variance across the site (see Fig. 2), with a significant correlation between predicted and true values (P ⬍ 10 ⫺10 , ⫽ 0.46, Kendall tau rank correlation). Of a total of 38 geochemical measurements, our predictions are significantly ac- curate for a wide range of 26 measurements ranging from manga- nese, a critical cofactor for many enzymes, to aluminum, which has a more limited important role in biological systems (P ⬍ 10 ⫺10 and P ⬍ 0.005, respectively, Kendall tau rank correlation) (Fig. 2). Although biologically relevant traits such as pH can be predicted more accurately than traits with less-direct ecological impacts, we found that natural bacterial communities create a broadly infor- mative imprint of their environment.
The problem of optical detection of small toxin molecules seemed to be resolved; the method of TIRE which is based on optical phase detection is capable of detection of mycotoxins down to 10 ppt concentrations and perhaps even below. The use of small size bio-receptors is beneficial, particularly for LSPR. However, the spectroscopic ellipsometry is still lab-based equipment, bulky, expensive, and not easy to use. What shell we do to fulfill the current demands of portable biosensors suitable for point-of need analysis? The answer lies in the use optical sensors based on phase detection, i.e. interferometers. Several recent developments of such devices proved to be successful ; they include dual polarization interferometers [52-54], ring-resonators , and Mach-Zehnder (MZ) interferometers [52, 56-58]. Biosensors based on MZ interferometers are perhaps the most popular devices which combine high sensitivity of detection and portable design [52, 56-58]. The development of a monolithic silicon-based MZ biosensor [59, 60] combining the light source, photo-detector, and multichannel waveguide equipped with microfluidic is particularly promising for point-of-need sensor development.
ABSTRACT: Biosensors are electronic devices that are sensitive to convert bio-recognition processes into measurable signals through a physicochemical process. They are highly sensitive, usually very selective and their development can be done easier, inexpensively and integrated in other devices. The biosensors can be classified based on the type of transducers into three categories, namely electronic (electrical or electrochemical) biosensors, optical biosensors (fluorescent, surface plasmon resonance, or Raman) and piezoelectric (quartz crystal microbalance) biosensors.According to the nature of biological recognition, there are several types of biosensors such as cellulose and cellulose-based composite, enzyme-based biosensors (EBB), immunological biosensors (IB), DNA-biosensors (DNA- B), microbial biosensors (MB) and graphene based biosensors (GBB).For the EBBs, three generations have launched between 1962 and 2003, namely glucose oxidase (GOD) enzyme, modified GOD- enzyme, and reconstructed GOD enzyme. The IBs are a new and cheap version of enzyme-linked immunosorbent assay (ELISA) with higher sensitivity and operation convenience. They can be classified into two types, namely a capture antibody that is immobilized at the electrode capturing specific target antigen and a capture antigen that is immobilized at the electrode capturing specific antibody. Different techniques have been developed to improve DNA hybridization detection including optical, acoustic and electronic devices. Among these methods, the fluorescent detection has preferred as genosensors in the few past decades. The MBs are analytical devices that integrate microorganism(s) with a transducer to measure a generated signal that is correlated to the analytes concentration.