A system (200, 250, 300, 350), comprising: a first reservoir (202, 252), the first reservoir containing an organic lipid stock solution; a first pump (206, 256) having a first pump inlet and a first pump outlet, the first pump inlet fluidically coupled to the first reservoir (202, 252); a second reservoir (204, 254), the second reservoir containing an aqueous nucleic acid stock solution; a second pump (208, 258) having a second pump inlet and a second pump outlet, the second pump inlet fluidically coupled to the second reservoir (204, 254); a valve (210, 260, 300, 350) having a first valve inlet port fluidically coupled to the first pump outlet, a second valve inlet port fluidically coupled to the second pump outlet, a first valve outlet port, and a second valve outlet port; and a mixing assembly (150, 212, 262, 302, 352) having a first mixing assembly inlet fluidically coupled to the first valve outlet port, a second mixing assembly inlet fluidically coupled to the second valve outlet port, and a mixing assembly outlet, wherein the first mixing assembly inlet is fluidically coupled to the mixing assembly outlet and the second mixing assembly inlet is fluidically coupled to the mixing assembly outlet; wherein the valve (210, 260, 300, 350) has a first operating position in which the first valve inlet port is fluidically coupled to the first valve outlet port and the second valve inlet port is fluidically coupled to the second valve outlet port and a second operating position in which the first valve inlet port is not fluidically coupled to the first valve outlet port and the second valve inlet port is not fluidically coupled to the second valve outlet port. a first reservoir (202, 252), the first reservoir containing an organic lipid stock solution; a first pump (206, 256) having a first pump inlet and a first pump outlet, the first pump inlet fluidically coupled to the first reservoir (202, 252); a second reservoir (204, 254), the second reservoir containing an aqueous nucleic acid stock solution; a second pump (208, 258) having a second pump inlet and a second pump outlet, the second pump inlet fluidically coupled to the second reservoir (204, 254); a valve (210, 260, 300, 350) having a first valve inlet port fluidically coupled to the first pump outlet, a second valve inlet port fluidically coupled to the second pump outlet, a first valve outlet port, and a second valve outlet port; and a mixing assembly (150, 212, 262, 302, 352) having a first mixing assembly inlet fluidically coupled to the first valve outlet port, a second mixing assembly inlet fluidically coupled to the second valve outlet port, and a mixing assembly outlet, wherein the first mixing assembly inlet is fluidically coupled to the mixing assembly outlet and the second mixing assembly inlet is fluidically coupled to the mixing assembly outlet; wherein the valve (210, 260, 300, 350) has a first operating position in which the first valve inlet port is fluidically coupled to the first valve outlet port and the second valve inlet port is fluidically coupled to the second valve outlet port and a second operating position in which the first valve inlet port is not fluidically coupled to the first valve outlet port and the second valve inlet port is not fluidically coupled to the second valve outlet port.