Chitin nanowhisker (30 μg/ml) pUC18 (200 ng/ml) Recipient cell Sliding friction Transformation efficiency (cfu/μg) + + + + 1.5E+04 - + + + ND + - + + ND + + - + ND + + + - ND cfu = colony forming units ND = Not detected

Table 1: Combination of factors needed to introduce donor pUC18 DNA into recipient E. coli cells.