*4.1.2 Electrodes*

Although carbon stick like a lead of a pencil works as an electrode, stainless steel wire in hardware stores is a good choice of electrodes for agarose gel electrophoresis. No expensive metal is needed; almost the cheapest one will be worth testing. Wireframe of 1-2 mm in diameter leads to a good result. Wires are run at the bottom corner of the tank, simply put by mending tape (**Figure 10**).

**Figure 10.** *An inexpensive stainless wire as electrodes of electrophoresis tank. This wire is 1.2 mm in diameter.*

**4.2 Power supply**

*4.2.1 DIY power supply*

**Figure 12.**

**Figure 13.**

**179**

*A DIY power supply based on a diagram of* **Figure 12***.*

needed in agarose gel electrophoresis.

*DOI: http://dx.doi.org/10.5772/intechopen.93439*

Basically, agarose gel electrophoresis is achieved in around 100 volts [19]. In laboratories of molecular biology and biochemistry, power supply for SDS-PAGE is very popular equipment. This supply gives fine and direct current, promising proteins to migrate correctly. Of course, this power supply is also available for use in agarose gel electrophoresis. But actually, such a high-quality direct current is not

*Cost-Effective Technical Tips for Agarose Gel Electrophoresis of Deoxyribonucleic Acid*

Generally, the household electric power is supplied as alternating current (**Figure 11(a)**). This alternating current is not usable as electrophoresis. The current is passed through a diode, and an odd part of the current is picked up (half-wave

To make half-wave or full-wave rectified current is not so difficult. **Figure 12** is a diagram showing full-wave rectification from alternating current. Four diodes are

rectification (**Figure 11(b)**)). A combination of diode enables to make all the alternating current as one direction (full-wave rectification (**Figure 11(c)**)). Half-wave rectified current and full-wave rectified current are a kind of pulsating current, which is not a true direct current (**Figure 11(d)**). It is known that such halfwave or full-wave rectified current is enough for agarose gel electrophoresis [20].

needed in this diagram, and they are substituted by one Graetz bridge.

*A simple circuit diagram of full-wave rectification for agarose gel electrophoresis.*

#### **Figure 11.**

*An alternating current (a), half-wave rectified current (b), full-wave rectified current (c), and a true direct current. (b) and (c) are enough for doing agarose gel electrophoresis, and true direct current like (d) is not needed.*

One avoidable notice is that copper is included in the wire as a component of wire. Copper is thought to be toxic, and it is ionized and flow out into the buffer during electrophoresis. Such a wire should be avoided, and it can be easily and clearly determined if copper is ionized because copper ion turns the buffer blue.

*Cost-Effective Technical Tips for Agarose Gel Electrophoresis of Deoxyribonucleic Acid DOI: http://dx.doi.org/10.5772/intechopen.93439*
