Electrostatic Droplet Generation for Encapsulat ion of Somatic Tissue: Assessment of High‐Voltage Power Supply

Abstract

The production of alginate microbeads with and without somatic tissue was investigated using an electrostatic droplet generator with a custom-made fixed (5.7 kV) and variable (0-20 kV) high-voltage power supply. The effects of applied potential, needle size, and alginate concentration were assessed as well as the immobilization of carnation callus cells. The high-voltage output from the power supply depended on whether the low-voltage input was increasing or decreasing. This hysteresis effect may be due to the electrical properties of the oscillator in the high-voltage source. While a short electrode distance and a high needle gauge were important for producing small alginate bead diameters (e.g., 100 µm), alginate concentration in the range 1-3% (w/v) was not a key factor. Somatic tissue encapsulated using 2% sodium alginate retained viability over a 2-month culture period.

Metalloporphyrin-based acetate-selective electrodes as detectors for enzymatic acetylcholine determination in flow-injection analysis system

“…Amberlite beads with immobilized enzyme were washed with 300 mL of MES buffer solution (pH 7.4) and then kept refrigerated. [29,30] Peroxydase (3.48 mg) and sodium alginate (20 mg) were mixed with 2 mL of TRIS buffer solution, pH 7.0. Obtained suspension was placed into the syringe pump, mounted over the beaker containing 100 mL of CaCl 2 solution (0.3 M).…”

Electrospray in the dripping mode for cell microencapsulation

“…studied the effect of electrode spacing, applied voltage and electrode geometry on the microbead size [22,23]. Subsequently, the effect of diameter of nozzle, viscosity of alginate solution, and flow rate of polymer solution on the microbead size and growth of plant callus cells encapsulated in alginate were investigated [24][25][26][27]. Watanabe et al studied the immobilized enzyme gel particles using electrostatic atomization technique and the corresponding catalytic performance of immobilized enzyme [28].…”

“…Two guluronate blocks of adjacent polymer chains can be cross-linked with multivalent cations (Ca 2+ , Cu 2+ , Ba 2+ ) through interactions with the carboxylic groups in the sugars, which lead to the formation of a gel network for use in cell microencapsulation by many researchers [2,4,[24][25][26][27]. Commonly, alginates with high guluronic acid content generate hard porous gels which can retain their integrity for long term.…”

Tissue transplantation by stealth—Coherent alginate microcapsules for immunoisolation

“…More sophisticated droplet generators employing coaxial air flow [84,90,91], electrostatic droplet generators [92], or laminar jet break up [93] have been used to reduce capsule size and increase throughput. However, as size decreases, the risk of graft material protruding through the capsule increases significantly, with an associated increase in graft failure [57,94].…”