The measurement of physical, physiological, and biological parameters using instruments in any living organism (including human beings) is what is referred to as bioinstrumentation.
However, bioinstrumentation in common layman language refers to instruments that are used to garner physiology related information---as for example recording or transmitting heart rate, breathing rate etc. In fact a bioinstrument could range from a heart monitor to artificial implantable organs. Therefore, it is a key device (like sensors, respirators or ultrasound equipment) that is of great importance to a patient as it deals with the measurement of physiological levels whether it is electrical waves or blood pressure. The design of bioinstrumentation is the cumulative result of synchronizing the technologies involved in optics, biology, electronics and biomedical engineering.
Electronics components that range from the simple microprocessor to the complex computers of today, together with the quantitative principles of measurement come into play in devising bioinstruments, whether they are used for diagnosis, treatment, or for analytical purposes. For instance, in medical imaging, large input of data has to be processed and for that advanced computing is essential. Generally bioinstruments have transducers or sensors that convert signals generated in the body (like for example signals generated by the sinoatrial node of the heart) to electrical signals that can be quantified. This means in order to design bioinstruments one must have knowledge of current, voltage, circuit theory and analysis, inductance, capacitance and several other fundamentals.
In this article we intend to discuss mostly about bioinstrumentation as applicable to agriculture, botany, and cellular and molecular biology especially with reference to microarrays, sequencing technologies, and lab automation technologies.
Here are some examples of bioinstruments in different disciplines.
Agriculture and Botany
In agriculture, soil monitoring instruments are used for monitoring and sampling the soil. For example, tensiometers measure the moisture content of the soil and this helps in maintaining conditions necessary for optimal plant growth. In addition if an electronic transducer is attached to the tensiometer and if the resulting data is connected to a datalogger then the plant can be monitored at regular intervals with respect to both soil moisture condition and water use profile of the plant. That apart, there are low-pressure chambers for analyzing soil water retention capabilities.
Agricultural biotechnology involves the handling of complex plant genomes and this needs complex instrumentation especially as several projects are underway to sequence the genomes of wheat, banana and beans.
Crop improvement requires identifying the gene. But the main problem is that plant genomes are generally big; say for example, wheat genome is several times bigger than the human genome. So to identify these genes and make chips requires much effort and instrumentation (gene arrays on nylon filters are used).
In botany, bioinstruments are used to measure plant metabolism. For example, the PTM-48A Photosynthesis Monitor can automatically record a plant's physiological characteristics like carbon dioxide exchange, leaf wetness, net photosynthesis, stomatal conductance and many other factors.
The process of plant tissue culture involves making plants or clones of plants under sterile conditions and this needs refined and higher resolution technologies. Often the whole process is preferred to be automated using microarraying technology and other lab automation equipment. At another level the LEADS computational biology platform or other similar platforms are used for enabling semantic integration of protein sequences.
The National Science Foundation's Plant Genome Research Program has probably provided the most impetus to the growth of bioinstrumentation---especially as interdisciplinary research is involved.
In microbiology and genetics
In microbiology and genetic testing specialized instruments like tissue analysis instruments, DNA/ peptide sequencers and synthesizers (peptide synthesizers like Apex peptide synthesizer can simultaneously make several different peptides), thermal cycler, Real time PCR gel electrophoresis, microarray based products and biosensors find use.
Flow cytometry is a key piece of instrumentation although some researchers prefer to use core facilities for cell analysis. But the comparatively low cost of flow cytometry has made it popular among some researchers. Apart from flow cytometry Laser scanning cytometry can give high-throughput analysis of heterogeneous tissue samples and facilitates proper functioning of imaging systems attached to it. A specific example is CompuCyte's iGeneration laser scanning cytometry .
Some if not most of the advances made in genomic research can be attributed to microarray technology. What is it? Microarrays can also be called DNA chips. Using microarray, researchers can measure the entire genome expression simultaneously. When two cell populations are compared microarrays, can find out which genes are activated and which are repressed. In research labs microarray technology plays a complimentary role for making oligonucleotides. Microarray technology in turn has helped develop technologies such as electrophoresis and nucleic acid amplification. That apart in genetics the human genome project has resulted in validation of several other systems useful for genome automation.
DNA sequencing is another key instrument especially with the ongoing several genomic projects. These are basically optical instruments with several lasers that emit at certain wavelength which gets absorbed by the dyes attached to the DNA strands under review. It is used for finding out the sequence of nucleotides in a given DNA sample. Earlier high throughput systems were preferred but now researchers prefer medium through put systems as they are better manageable. As a corollary to this several reagents are also required.
In medicine, bioinstruments constitute vaporizers, oxygen mask, suction catheters, respirators, defibrillators and the usual pumps for delivering anesthesia and insulin. That apart, there are electronic multi-parameter brain and whole body monitors ( essentially an instrument that quantifies biomarkers in the body) that measure ECG, blood pressure, pulse and pulse oximetry, respiration rate, CO2, glucose levels, blood alkalinity or acidity (or levels of other chemicals and electrolytes) and other specialized parameters.
An example of the general patient monitoring system would be the Goldway Multiparameter Monitor that can do multi-gas monitoring, take ECG, and monitor respiratory and pacemaker function. Other bioinstruments include sensors that can monitor blood flow rate, brain electrical activity and muscle electrical activity (electromyography). For example in order to detect carpal tunnel syndrome and muscular dystrophy electromyography is used. Even pacemakers and hearing aids can also be categorized as bioinstruments---- the key point being that these bioinstruments assist physiological functions.
In surgery, biomedical optics helps design non-invasive surgical techniques (without making incision with normal surgical instruments) using state of the art imaging machinery like CAT scanners. An example is LASIK eye surgery for resolving astigmatism or myopia.
In Chemistry/Pharmacology/Veterinary Science
In pharmacology, apart from instruments to measure chemical reactions moisturemeter and Corneometer are used especially for the analysis of moisture retention capacity of the skin as that is essential for diagnosis of skin conditions as well as for designing ointments and cosmetics. In veterinary science, bio instruments are used for neutering of animals and in zoology there are instruments for organ modeling.
Standalone Breakthrough Bio-instruments
Researchers are developing some breakthrough bioinstrumentation some of which are detailed below.
Biosensors to diagnose Myocardial Infarction by focusing on molecular markers
In developing economies, detection of Acute Myocardial Infraction through cost effective means is of vital importance, as it is a fairly common disease. Now researchers are developing biosensors that use optical and electrical means to detect the disease at the outpatient level. These biosensors are expected to detect molecular markers of MI. For example one such experimental biosensor (Hotwire Induced Pyrolytic Process) uses silicon dioxide and silicon nitride (for optical detection) and piezoresistive cantilevers for electrical readout.
Micro array for multiple clinical diagnoses
Tests involving multiple clinical diagnoses generally require several blood samples and so does not reckon with time and cost constraints. Multianalyte immunoassay technology obviates the need for that and now microarrays are designed that can detect cancer antigen from human serum apart from analyzing other parameters. The principle involved is calorimetric resonance reflection detection technique.
Biosensor for detection of waterborne pathogens and bacteria
Now biosensors that use embedded processors and photodetectors are available that can detect pathogens and other biomolecules through Surface Plasmon Resonance technique.
Another research effort aims to develop a biosensor (using immunoassays and superior transduction techniques such as optical sensing) for detecting bacteria in the environment.
The rapid sequencing of plant genomes can be partly attributed to the fact that bioinstrumentation technology has made the whole process less expensive now than it was before. As you can see from this article, a laboratory doing research in genomic and proteomic domain would require bioinstrumentation that involves a mix of electronic instrumentation and chemistry. In addition for analyzing genomic or proteomic data bioinformatics tools are a must---this could be in terms of latest software and databases. In short, microicroarray/biosensor, real-time PCR and bioinformatics constitute key segments in bioinstrumentation.
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