An apparatus comprising: a microneedle assembly comprising a base surface , a plurality of microneedles extending outwardly from the base surface , and a pathway at least partially defined by a microneedle of the microneedle assembly ; and a membrane draped over at least a portion of the plurality of microneedles , the membrane comprising: an elongate aperture that is open along a length of the pathway so that the elongate aperture is in fluid communication with the pathway , wherein said elongate aperture has a length (L1) and a width (W1), the length (L1) being greater than the width (W1), an outer portion in opposing face-to-face contact with at least an outer portion of the microneedle , and an inner portion facing toward at least a portion of the base surface , wherein at least a portion of the membrane is spaced apart from the microneedle so that a gap is defined between the membrane and the microneedle ; the gap extends both at least partially around the microneedle and at least partially along the microneedle ; the membrane defines a pleat extending between the inner and outer portions of the membrane , and the pleat is positioned relative to the elongated aperture to control the size of the elongate aperture and the size and shape of the gap . a microneedle assembly comprising a base surface , a plurality of microneedles extending outwardly from the base surface , and a pathway at least partially defined by a microneedle of the microneedle assembly ; and a membrane draped over at least a portion of the plurality of microneedles , the membrane comprising: an elongate aperture that is open along a length of the pathway so that the elongate aperture is in fluid communication with the pathway , wherein said elongate aperture has a length (L1) and a width (W1), the length (L1) being greater than the width (W1), an outer portion in opposing face-to-face contact with at least an outer portion of the microneedle , and an inner portion facing toward at least a portion of the base surface , wherein at least a portion of the membrane is spaced apart from the microneedle so that a gap is defined between the membrane and the microneedle ; the gap extends both at least partially around the microneedle and at least partially along the microneedle ; the membrane defines a pleat extending between the inner and outer portions of the membrane , and the pleat is positioned relative to the elongated aperture to control the size of the elongate aperture and the size and shape of the gap . an elongate aperture that is open along a length of the pathway so that the elongate aperture is in fluid communication with the pathway , wherein said elongate aperture has a length (L1) and a width (W1), the length (L1) being greater than the width (W1), an outer portion in opposing face-to-face contact with at least an outer portion of the microneedle , and an inner portion facing toward at least a portion of the base surface , wherein at least a portion of the membrane is spaced apart from the microneedle so that a gap is defined between the membrane and the microneedle ; the gap extends both at least partially around the microneedle and at least partially along the microneedle ; the membrane defines a pleat extending between the inner and outer portions of the membrane , and the pleat is positioned relative to the elongated aperture to control the size of the elongate aperture and the size and shape of the gap . <EOS>