Measuring the density of DNA films using ultraviolet-visible interferometry

Area of Science:

• Biophysics
• Materials Science
• Spectroscopy

Background:

• Accurate density values for deoxyribonucleic acid (DNA) films are crucial for various scientific applications.
• Previous estimations of DNA film density (1.7 g/cm³) may be inaccurate, affecting derived physical properties.
• Understanding DNA film formation and its dependence on sample composition is an active area of research.

Purpose of the Study:

• To accurately determine the density of dry DNA films.
• To establish a reliable method for measuring DNA film density.
• To provide a more precise value for DNA density, enabling recalculation of optical constants.

Main Methods:

• Utilized interference effects in transmission spectra of thin DNA layers.
• Employed a novel methodology to measure thin film properties.
• Focused on transmission spectra analysis for density determination.

Main Results:

• The developed methodology effectively measured DNA film density.
• The determined density of dry DNA films is 1.407 g/cm³.
• This value is substantially lower than the commonly accepted density of 1.7 g/cm³.

Conclusions:

• The new DNA film density (1.407 g/cm³) necessitates recalculation of DNA optical constants.
• The measurement technique is valuable for characterizing particle interactions with DNA films.
• Accurate DNA density is important for understanding sample composition effects on film formation and dose dependence.