Many methods to identify alternative technologies for separation of protein have been looked into regularly but electrophoresis is supposed to serve for a long time to come, because of its wide application fields, availability, easier techniques, and costing. It has shown advanced technologies both in gel electrophoresis (GE) and capillary electrophoresis (CE), over the years with the increasing use in diagnostics, forensic, microbiology genetics, and food industries. This growth of varied use has brought in necessary parallel development in the diversification of the industry business in areas of instrumentation, supplies, and services.
Although electrophoresis is a standardized technique, there have been considerable technology advances because of its ever-expanding research applications. Among the major GE techniques, the polyacrylamide gel - 2D PAGE - technique has received immense attention, fueled by the growing field of proteomics. A striking example of technology enhancement is the 2D DIGE. This method, which provides a higher accuracy of quantitative data with minimal occurrence of false positives, has been a principal driving force behind advancements in proteomics research and is driving niche-market participants to develop reagents tailored for this method.
With the advent of techniques like high-throughput DNA sequencing, application of electrophoresis variants like CE plays a crucial role in segregation of nucleic acid fragments and is frequently used in diagnostics and research. CE has also shown a steep incline, especially in medical diagnostics over the past couple of years. The current thought process is in the evaluation of lab-on-a-chip (LOC) electrophoresis on capillary technology.
LOC and Proteomics
In the field of proteomics, LOC provides the opportunity to perform protein analyses while integrating all the steps within the same chip - extraction from the cell, separation by electrophoresis, digestion, and analysis using mass spectrometry. Electrophoresis is the mainstay of LOC implementation of molecular biology procedures and is the basis for many medical diagnostics.
Separation of double-stranded and single-stranded DNA is obtained in a few minutes and at a low expense by making use of reusable glass chips. Reliable chip-based technique for rapid molecular diagnosis and detection of genetic variations, such as single-nucleotide conformation polymorphisms (SSCP) method of gene-scanning and mutations has been successfully adapted to chip-based solutions. The characteristics, low power consumption, short time analysis, sensitivity and simple â€¨real-time detection system, in addition to diminutive size and portability make these chips suitable for rapid and sensitive genetic diagnosis.
Though LOC technology has already proved its mark as a significant tool for research and development, it is still viewed to be in its initial stages and more advancement in this technology still continues in many fields to meet the growing need for miniaturization, not only to diminish the expenses but also to develop it as a tool for green analytical chemistry so as to reduce the impact of research on the environment. Looking at recent research and products entering the market, LOC will change the way diagnostics is done in future.
Advances in Instrumentation
With investments in clinical research progressively rising, spending on instrumentation used for analytical chemistry is expected to rise continually as well. Analytical chemistry has proven useful in studying the composition of materials to find new applications for them or to modify their composition as desired. One of the well-established analytical separation techniques is capillary electrophoresis (CE). Owing to its high versatility, major advancements have been made with regard to the instrumental set-ups during the last years. New strategies have been proposed to develop high-sensitive methods, portable CE, or miniaturized devices.
Capacitively coupled contactless conductivity detection (C4D). This may be the detection method of choice for portable systems, in view of its low power consumption, the possibility for miniaturization, high versatility, and ease of construction and operation. Due to its simplicity, the instrument is compatible with circumstances in which there are financial constraints. The instrument is inexpensive and can be assembled with little effort. In comparison to the automated versions, this instrument allows use of much smaller sample volumes, which is an extra advantage. The system is yet to be used for on-site applications, but it may already be serving as a low-cost instrument in the laboratory.
Capacitance-to-digital conversion technology (CDC). Another detection technique with extremely low power consumption and space requirements (size 25-17 mm) is the CDC. It is similar to C4D in that it also measures complex impedance, but the signal conversion differs from conventional analog-to-digital modulation. It can compete with known miniaturized C4D and UV detectors in terms of sensitivity, resolution, size, and power requirements. The low working frequency of this detector minimizes stray capacitance and it may be used in indirect mode with an ascorbic-acid background electrolyte. In addition, a â€¨high-conductivity borate buffer can be used as a background electrolyte in combination with this detector, which is not the case with a C4D detector.
Portable micro-coil NMR detection coupled to CE. Coupling a commercial CE instrument to a portable NMR instrument is feasible and can provide a low-cost method to obtain structural information on microliter samples in a non-destructive way. The radiofrequency micro-coils used in this form of NMR have been downsized. In view of the fact that the sensitivity improves with decreasing the coil diameter, improved mass sensitivity may be observed. However, in view of the fact that concentrations required are still relatively high, non-standard CE conditions had to be incorporated. Full portability would be achieved by coupling this portable NMR system to a portable CE instrument, offering also a reduced footprint.
In the coming years, more efforts and improvements are needed in sections such as the new chemiluminescence (CL) reagents, the CE-CL detection interfaces and modes, and novel methodologies for CE-CL and MCE-CL. The developments in miniaturization, integration, and automation make it possible for the commercialization of CE-CL system, which will promote further research interest and broad acceptance in more fields.
The availability of good-quality portable devices is of great importance. Progress in this kind of instrumental analysis has been made at the level of detection as well as the separation part. For instance, a replaceable C4D cell cartridge has been developed which can be used in combination with a microfluidic device. The scientific community is looking forward to even more new developments that will enhance the portability and applicability of electro-migration separation techniques.
Some electrophoresis techniques involve time-consuming operations and offer limited sample analysis. Therefore, in future, manufacturers should focus on providing instruments that are efficient, accurate, and competitively priced to increase productivity of laboratories.