Techniques in Forensic Biology

The acid phosphatase test is a useful technique to use for detecting prostate cancer.glass beakers image by Mark Aplet from Fotolia.com

Techniques developed by forensic biologists are used in medical labs around the country. These techniques assist police personnel in identifying perpetrators of serious offenses as well as helping doctors diagnose disease by detecting the presence of bodily fluids in samples. Without these techniques, medicine and criminal detection would still be very much in the dark.

Acid Phosphatase Test

The acid phosphatase test is a technique used to detect the presence of semen on clothing, in vaginal fluid or on other objects. The technique is effective because the acid phosphatase enzyme is found in the prostate gland at amounts nearly 100 times greater than anywhere else in the male body. The compound is combined in a lab with acetic acid, sodium acetate and water. The solution turns purple when there are high amounts of acid phosphatase, letting the forensic biologist know that he likely has evidence with semen present on it.

This technique is used by forensic biologists and technicians to detect the presence of blood and its properties on objects. This is especially useful in crime scene investigation when surfaces may have been wiped clean and blood is not visible to the naked eye. The test involves combining a swab of the suspected surface with a prepared solution of hydrogen peroxide, zinc powder and deionized water. This chemicals produce a bluish green hue in the presence of blood and its components.

Capillary electrophoresis is a technique used to extract DNA using a device that generates a high voltage current. The voltage causes particles to separate into heavier and lighter molecules when "pushed" through a narrow capillary or tube. The particles are then collected by storage containment units built into either end of the device. This technique is used when only a small amount of DNA is recovered from a crime scene or when the DNA recovered is combined with other materials and requires separation to get an accurate sampling.

One of the oldest techniques in forensic biology involves the detection of fingerprints. According to the website for Bronx Science, forensic biologists use a number of techniques to detect fingerprints such as finely ground charcoal brushed over surfaces and chemical vapors. Heated iodine crystals are used to allow vapors to attach to the oils left by human skin as well as cyanoacrylate ester when combined with sodium hydroxide. This allows technicians to obtain fingerprints without having to touch the surface of the object with the print. This reduces the chance of ruining the evidence and smudging the print.