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SEM images of PLLA microfibers electrospun at a traveling distance of 15 cm, a needle diameter of 0.50 mm, an applied voltage of 20 kV, flow rate of 4 ml h−1 and a rotation speed of 500 rpm (a), 750 rpm (b), 1000 rpm (c) and 1500 rpm (d). The scale bar corresponds to 20 μm.
