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Electrophoresis
Context:
Innovative advancements in biomedical engineering have led to the development of hand-held “electric labs” that can rapidly identify pathogens. These portable devices utilise a technique called electrophoresis, which separates molecules based on their electrical charge.
Electric fields are invisible forces that play a crucial role in many areas of science, from powering modern life to advancing research in biology and medicine. While we often associate electric fields with the devices that power our homes or gadgets, they also have significant applications in the study of molecular biology, particularly through a technique called electrophoresis.
Electrophoresis Overview:
- Electrophoresis is a technique that uses electric fields to separate molecules, such as DNA and proteins, based on their charge.
- This principle, rooted in the work of scientists in the 19th century, is now widely used in biology and clinical labs to analyse DNA, proteins, and pathogens.
- How It Works: In electrophoresis, an electric field is created between two electrodes (positive and negative) in a container with conductive water and salt, which pushes charged particles toward the oppositely charged electrode.
- Factors Affecting:
- Strength of Electric Field: Higher voltage increases the migration speed.
- Molecular Size and Shape: Smaller molecules move faster through the gel matrix.
- Buffer Composition: The ionic strength and pH of the buffer can affect the charge and mobility of the molecules.
- Temperature: Higher temperatures can increase the mobility of molecules but may also affect the stability of the gel
Types:
- Gel Electrophoresis: It involves the separation of molecules through a gel matrix, such as agarose or polyacrylamide. The gel acts as a sieve, allowing smaller molecules to move faster than larger ones.
- Capillary Electrophoresis: In this method, the separation occurs in a small capillary tube filled with a buffer solution. It is highly efficient and used for separating small quantities of molecules with high resolution.
- Paper Electrophoresis: This technique uses filter paper as the supporting medium. It is simple and cost-effective but less commonly used compared to gel electrophoresis.
- Free Boundary Electrophoresis: Developed by Arne Tiselius in 1937, this method involves the separation of charged particles in a free solution without a supporting medium.
Advancements in Electrophoresis:
- Nonlinear Electrophoresis: Discovered in 1972, this variation of electrophoresis not only separates particles by charge but also by their size and shape, providing a more advanced method for particle separation.
- Electric Fields and Pathogen Detection: In 1999, it was discovered that tiny electrophoresis systems could separate bacteria by their electrical charge, enabling identification of different species in under 20 minutes.
- Microfluidic systems are smaller, portable, and much faster (2-3 minutes) compared to conventional systems (40-50 minutes), allowing for more efficient pathogen detection.
Applications:
- Applications in Medicine: Microfluidic electrophoresis could revolutionise fields like antibiotic testing and infection control by allowing for quick detection of whether bacteria are dead after treatment and distinguishing between normal and antibiotic-resistant bacteria.
- Additionally, the technique is being explored for purifying bacteriophages for infection treatment.
- Rapid Disease Detection: They can quickly identify pathogens in clinical and field settings, aiding in the timely diagnosis and treatment of infectious diseases.
- Research and Development: Scientists can use these devices to study the genetic material of various organisms, advancing our understanding of biology and genetics.
- Environmental Monitoring: They can detect harmful microorganisms in water, soil, and air, helping to monitor and address environmental contamination.
Future Prospect:
- These small, fast, and portable devices have wide-ranging potential, especially in medicine, where they can replace conventional methods with quicker, more cost-effective results.
- Continued development can enhance the ability to rapidly detect and fight pathogens, improving diagnostic and treatment options.
