Effect of equilibrium pH on the structure and properties of bleach-damaged human hair fibers.

Hair proteins are significantly affected by environmental pH. This impact tends to increase with prior hair damage. To understand how pH affects bleached hair properties, we utilized a number of techniques allowing for the determination of hair thermal properties, swelling and water sorption, and dry and wet tensile properties.

The effects of water on heat-styling damage.

Heated styling appliances, such as straightening irons, have grown in popularity in recent years, as have hair products such as heat-protection sprays. In this study we investigate whether the water in a heat-protection spray can affect the level of damage caused by heat styling. Tryptophan damage from heat styling was measured using fluorescence spectroscopy, and structural damage was investigated using light microscopy and single-fiber tensile testing.

Analysis of DNA in hair fibers.

The extraction and identification of deoxyribonucleic acid (DNA) from human hair shafts is described, along with the effects of hair treatments on levels of DNA and suggestions of DNA location within the shaft. DNA was present at low levels in the hair shaft, and was identified using polymerase chain reaction amplification of the human leukocyte antigen (HLA)-DQA1 locus. The use of cleanup columns aided the success of PCR amplification.