A protocol was developed for preparing lip balm coatings to enable their physicochemical characterization and studies of virus adhesion. Surface charge and hydrophobicity of four brands of lip balm (dry and hydrated) and human adenovirus 5 (HAdV5) were measured and used to calculate the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) energy of interactions between lip balm coatings and HAdV5 as well as four other colloids: HAdV40, MS2 and P22 bacteriophages, and SiO₂. Quartz crystal microbalance with dissipation monitoring (QCM-D) tests employed SiO₂ colloids, HAdV5 and hydrated lip balm. Drying of lip balms results in a dramatic decrease of their surface energy (83.0 mJ/m²), making the surface highly hydrophobic. For dry lip balms, the interaction with all five colloids is attractive. For lip balms hydrated in 150 mM NaCl (ionic strength of human saliva), XDLVO calculations predict that hydrophilic colloids (MS2, P22, SiO2) may attach into shallow secondary minima. Due to the relative hydrophobicity of human adenovirus, primary maxima in XDLVO profiles are low or non-existent making irreversible deposition into primary energy minima possible. QCM-D tests with SiO2 colloids and HAdV5 confirm deposition on a hydrated lip balm.

QCM-D measurements of the deposition of<b> </b>human adenovirus 5 onto hydrated Carmex lip balm from 150 mM NaCl electrolyte at pH 7.2. HAdV5 concentration in the QCM-D feed is ~10<sup>9</sup> GC/mL (~ 0.76 µg/mL). The mass values are calculated based on Sauerbrey equation with n<!--[if gte msEquation 12]><m:oMath><i style='mso-bidi-font-style:normal'><span style='font-size:11.0pt;font-family:

n = 3."/>

QCM-D measurements of the deposition of human adenovirus 5 onto hydrated Carmex lip balm from 150 mM NaCl electrolyte at pH 7.2. HAdV5 concentration in the QCM-D feed is ~10⁹ GC/mL (~ 0.76 µg/mL). The mass values are calculated based on Sauerbrey equation with n = 3.

Reyhan Sengür-Tasdemir

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