Tape Strips in Dermatology Research

A. J. Hughes; S. S. Tawfik; K. P. Baruah; E. A. O'Toole; R. F. L. O'Shaughnessy


The British Journal of Dermatology. 2021;185(1):26-35. 

In This Article

What is the Expected Yield Per Sample?

RNA and protein yield are higher when there is active disease, such as lesional AE relative to nonlesional AE.[43,50,51] Different TS collection protocols, as summarized in Table 3, also affect protein yield.

Breternitz et al. used optical spectroscopy to measure the total protein content on sequential TS from healthy patients using different variables. Overall, 32 TS achieved an average yield of 8–12 μg per strip depending on the protocol.[7] Superficial strips had a higher yield per strip, suggesting that protein yield with each TS is not linear.[7] Clausen et al. studied total and soluble protein yield per TS from 35 TS in AE and healthy controls,[50] and demonstrated that each TS yielded on average 77 μg per tape of soluble protein and 260 μg per tape of insoluble protein from healthy patients but with high interindividual variance.[50]

RNA yield is reported less often and is generally low. Studies are not directly comparable, as there is no interstudy standardization. The highest yield was 300 ng from 30 TS in healthy controls using vigorous shaking in RNAzol to detach the RNA.[55] The lowest yield was an average of 0·11 ng from TS 11–20 in patients with AE using a cell scraper.[51] The latter study compared this with the yield from epidermal biopsies, which was higher at 3·55 ng per sample.[51] RNA is not always detected, the highest sample detection rate was 100%[2] and the lowest was 45%.[43]

There has been no study that directly compared the yield of different RNA extraction protocols. We performed our own experiments comparing different extraction methods on a single set of TS cut into quarters. We found that rubber scraping gave the highest yield compared with sonication or vigorous shaking (Figure 3). Long sonication times can degrade RNA,[56] whereas shorter sonication (90 s)[56] may not sufficiently detach keratinocytes.[50,57]

Figure 3.

Bar charts comparing the total RNA yield from different extraction techniques. A set of tape strips (number 11–20) was cut into quarters. Pooled sets of quarters were subject to different extraction techniques using the RNeasy Plus Micro Kit (Qiagen, Hilden, Germany). Vigorous shaking lasted for a duration of 150 s. Sonication took place for a total of 90 s on high with a 30-s interval every 30 s. RNA was quantified using a one-step RT-PCR kit using 18S rRNA primers against a HeLa RNA standard (RNA Quantification Kit for SYBR Green I and ROX Passive Reference Dye, ThermoFisher Scientific, Waltham, MA, USA). P < 0·05 was calculated using the Kruskal–Wallis nonparametric analysis. Three experimental replicates were performed. Ct, cycle threshold.