An emulsion system includes a plurality of monodisperse particle-drops. Each particle-drop is formed by a single elongated drop-carrier particle disposed in an oil-based continuous phase, wherein the single elongated drop-carrier particle comprises an elongate body with an opening at one end thereof. The single elongated drop-carrier particle has a hydrophilic interior region containing an aqueous droplet and a hydrophobic exterior region. The aqueous droplet and/or a surface of the hydrophilic interior region may contain one or more reagents, analytes, labels, reporter molecules, and/or cells.