Protein adsorption to the inner capillary wall hinders the use of kinetic capillary electrophoresis (KCE) when studying noncovalent protein-ligand interactions. Permanent and dynamic capillary coatings have been previously reported to alleviate much of the problems associated with protein adsorption. The characteristic limitations associated with permanent and dynamic coatings motivated us to look at a third type of coating - semipermanent. Here, we demonstrate that a semipermanent capillary coating, designed by Lucy and co-workers, comprised of dioctadecyldimethylammonium bromide (DODAB) and polyoxyethylene (POE) stearate, greatly reduces protein adsorption at physiological pH - a necessary requirement for KCE. The coating (i) does not inhibit protein-DNA complex formation, (ii) prevents the adsorption of the analytes, and (iii) supports an electoosmotic flow required for many applications of KCE. The coating was tested in three physiological buffers using a well-known DNA aptamer and four proteins that severely bind to bare silica capillaries as standards. For every protein, a condition was found under which the semipermanent coating effectively suppresses protein adhesion. While no coating can completely prevent the adsorption of all proteins, our findings suggest that the DODAB/POE stearate coating can have a broad impact on CE at large, as it prevents the absorption of several well studied, highly adhesive proteins at physiological pH.

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ObjectivesSex workers (SWs) face a disproportionate burden of HIV/sexually transmitted infections (STIs), violence and other human rights violations. While recent HIV prevention research has largely focused on the HIV cascade, condoms remain a cornerstone of HIV prevention, requiring further research attention. Given serious concerns regarding barriers to condom use, including policing, violence and ‘end-demand’ sex work criminalisation, we evaluated structural correlates of difficulty accessing condoms among SWs in Vancouver over an 8-year period.MethodsBaseline and prospective data were drawn from a community-based cohort of women SWs (2010–2018). SWs completed semi-annual questionnaires administered by a team that included lived experience (SWs). Multivariable logistic regression using generalised estimating equations (GEE) modelled correlates of difficulty accessing condoms over time.ResultsAmong 884 participants, 19.1% reported difficulty accessing condoms during the study. In multivariable GEE analysis, exposure to end-demand legislation was not associated with improved condom access; identifying as a sexual/gender minority (adjusted odds ratio (aOR) 1.62, 95% CI 1.16 to 2.27), servicing outdoors (aOR 1.52, 95% CI 1.17 to 1.97), physical/sexual workplace violence (aOR 1.98, 95% CI 1.44 to 2.72), community violence (aOR 1.79, 95% CI 1.27 to 2.52) and police harassment (aOR 1.66, 95% CI 1.24 to 2.24) were associated with enhanced difficulty accessing condoms.ConclusionsOne-fifth of SWs faced challenges accessing condoms, suggesting the need to scale-up SW-tailored HIV/STI prevention. Despite the purported goal of ‘protecting communities’, end-demand criminalisation did not mitigate barriers to condom access, while sexual/gender minorities and those facing workplace violence, harassment or those who worked outdoors experienced poorest condom accessibility. Decriminalisation of sex work is needed to support SWs’ labour rights, including access to HIV/STI prevention supplies.