Ussing System Options

Benefits

• Leak free design of Ussing chambers
• Can be used with monolayer cell culture inserts
• Optional drains for quick evacuation of radioactive or toxic substances
• Circulation reservoirs available in two sizes
• Control temperature with a circulating water bath (option) available

Applications

• Ion transport studies
• Nutrient transport studies

WPI’s Ussing System offers researchers a quick, effective means of making low-resistance electrical connections to the Ussing chamber without need of long agar bridges or Calomel half-cells. Ag/AgCl half-cells screw into short tubes which plug firmly into place in the chamber’s Luer ports. These direct-connect elec­trodes eliminate the inconvenience and expense of Calomel half-cells in open liquids. The system includes one Ussing Chamber (eight sizes available), support stand, electrode kit, glass circulation reservoir (two sizes available), and a tub­ing start-up kit (25 feet of 0.375-in. tubing, 10 feet of 0.156-in. tubing, plus four male Luer fittings, two compressor clamps, one Y-connector, and one clip). Six­teen possible system configurations are list­ed at right. Com­po­nents are also avail­able sep­a­rate­ly. (Preamplifier in pho­to not included.)

Leak free design of Ussing chambers

WPI’s classical Ussing Chambers are well established perfusion chambers that are easy to operate, easy to control temperature, and easy to clean after use. Ussing Cham­bers are machined from solid acrylic with eight entry ports for fluid lines, elec­trodes, or agar bridges. For easy, leak-free attachment of tubing and elec­trodes, all eight ports are Luer type. The four ports for volt­age and current electrodes are re­cessed to prevent formation of air bubbles in the chamber. The fluid com­part­ments in each side of the chamber are sep­a­rat­ed by the epithelial membrane being stud­ied. Sharp stainless steel pins on one side of the chamber hold the mem­brane in po­si­tion and mate with holes in the opposite chamber in­ter­face. (In the CHM4, tissue is held by an O-ring instead of pins.)

Can be used with monolayer cell culture inserts

TheCHM5chamber adapts the Costar Snapwell, a cell cul­ture in­sert for mono­lay­er cell culture, into WPI’s “classical” ep­i­the­lial volt­age clamp sys­tem. Classical Ussing Cham­bers have not been widely used for mono­lay­er cell culture in­serts, be­cause most inserts have a very deep pro­file, limiting good fluid per­fu­sion at the surface of the mem­brane and limiting voltage elec­trodes from measuring the po­ten­tial close to the sur­face of the mem­brane.CHM5solves these problems: Per­fu­sion fluid is in­tro­duced into the chamber at an angle so that it flows directly to the surface of the mem­brane. The volt­age elec­trode is also in­sert­ed into the cham­ber at an angle to reduce the distance between the surface of the membrane and the electrode.

Rectangular openings for tubular tissue

Two small chambers with rectangular openings are designed for tubular tis­sue from small an­i­mals such as the mouse intestinal tract membrane (CHM6) and rat in­tes­ti­nal tract mem­brane (CHM7). The rect­an­gu­lar open­ing more close­ly match­es the shape of the tissue than would a circular open­ing, sig­nif­i­cant­ly increasing the mem­brane area available for testing. The larger mem­brane area increases the transport rate of low permeability chemicals. It also reduces the electrical re­sis­tance of the system for easier current clamp­ing.

Optional drains

Drains may be added to Ussing chambers to allow quick and complete evac­u­a­tion of radioactive or tox­ic sub­stanc­es. To have drains added at the time of or­der, add a “D” to the part number (such as “USS1LD”). The cost of the drain will be add­ed to the cost of the cham­ber or system or­der­ed.

Cartridge electrodes

The Electrode Kit contains four voltage/current electrodes, plus four Luer-tipped cartridges. Elec­trodes are thread­ed and screw securely into the end of each car­tridge. The Luer tip then plugs securely into the Luer open­ings of the cham­ber. The ca­ble from each elec­trode ter­mi­nates with a 2 mm pin which may be plugged into voltage/current clamps such as WPI’s EVC-4000 using the EVC3. The miniature electrode-gel cartridge is a small plastic tube with a male Luer tip identical to those at the tip of hy­po­der­mic syringes. The tube may be filled with different gel ma­te­ri­als. Agar is com­mon­ly used, but other gel ma­te­ri­als may also be sat­is­fac­to­ry.

Circulation reservoirs available in two sizes

Hand-blown boro­sil­i­cate glass reservoirs with jacketed cham­bers for tem­per­a­ture con­trol are avail­able in two siz­es:

• #5210 holds 20 mL per side
• #5362 holds 10 mL per side (use­ful when ex­pen­sive chem­i­cals are in­volved).

Res­er­voir con­dens­er caps pre­vent air bub­bles and tur­bu­lence in flu­id res­er­voirs.

Reservoir openings and pins

All systems include the stand, selectedreservoir, selected chamber,electrodes and tubing.