The Biflow: an instrument for transfer-loop mediated, continuous, preparative-scale isoelectric trapping separations

Area of Science:

• Biochemistry
• Analytical Chemistry
• Separation Science

Background:

• Isoelectric focusing is a powerful technique for separating ampholytic molecules based on their isoelectric point (pI).
• Traditional methods for obtaining narrow pI fractions can be time-consuming and involve multiple steps.
• A need exists for efficient, single-step instruments capable of isolating specific pI ranges from complex biological mixtures.

Purpose of the Study:

• To introduce and characterize the Biflow, a novel instrument designed for single-step isolation of narrow isoelectric point (DeltapI) fractions.
• To demonstrate the Biflow's capability in separating target molecules from complex mixtures with high precision.
• To validate the instrument's performance through practical applications in biochemical separations.

Main Methods:

• The Biflow instrument utilizes two interconnected separation units, each with distinct buffering membranes to establish a defined pI range (DeltapI).
• A recirculating transfer loop facilitates the selective movement of ampholytic components based on their pI relative to membrane pH.
• The system employs independent power supplies for each unit to control the electrophoretic migration and trapping of target molecules.

Main Results:

• The Biflow successfully isolated carnosine from a mixture containing UV-absorbing ampholytes, showcasing its ability to handle complex feed streams.
• The instrument effectively separated minor constituents from chicken egg white within specific narrow pI ranges (4.4
• The double transfer mechanism within the Biflow ensured the exclusion of components outside the desired DeltapI range from the final harvest.

Conclusions:

• The Biflow instrument provides an efficient and effective single-step solution for obtaining narrow DeltapI fractions from complex mixtures.
• This technology offers significant advantages for biochemical research and purification processes requiring precise separation of ampholytic compounds.
• The demonstrated utility in isolating specific compounds and isoforms highlights the Biflow's potential for various applications in analytical and preparative biochemistry.