Capillary puller

For microinjection experiments, standard or inverted microscopes are used (e.g., Zeiss Axioskop with transmitted light phase contrast and the mechanical micromanipulator from Leitz (see Fig. 1). The capillary puller is homemade (Fig. 2). The glass tubes (1.4-mm outer and 1.2-mm inner diameters) for preparation of the injection capillaries are obtained from either Schott or Clark Electromedical Instruments. Sterile capillaries can be obtained from Eppendorf. 

Clamp the glass tubes into a capillary puller. The diameter and the shape of the tip depend on the heat of the wire and on the force that pulls the glass tubes into two identical capillaries. The diameter at the tip should be about 0.3-0.5 mm (see Fig. 2). 

A glass tube (1.5 mm dia) was pulled with a capillary puller. The capillary was filled with an electrolyte (3.0 M KCl), into which platinum wire was inserted. 

Since the mass-transfer coefficient at a micropipette is inversely proportional to its radius, the smaller the pipette the faster heterogeneous rate constants can be measured. Micrometer-sized pipettes are too large to probe rapid CT reactions at the ITIES. Such measurements require smaller (nm-sized) pipettes. Nanopipettes are also potentially useful as SECM tips (see Section IV.D) because they can greatly improve spatial resolution of that technique. The fabrication of nanopipettes was made possible by the use of a micro-processor-controlled laser pipette puller capable of puling quartz capillaries [26]. Using this technique, Wei et al. produced nanopipettes as small as 20 nm tip radius and employed them in amperometric experiments [9]. 

We use 100 pi glass capillary tubes (VWR international 53432-921) pulled by a horizontal micropipette puller (Sutter Instrument Co. Model P-97) for suctioning of adipose tissue. Suction strength is controlled by tip size which is typically 10-20 pm. 

The capillary-wire unit is introduced into the microelectrode puller. It is placed at the center of an electrical resistance temperature is increased by Joule effect. The capillary is then stretched to obtain two similar microelectrodes. 

The procedure for the fabrication of the Pt submicroelectrodes is shown in Fig. 3.16 (Slevin etal. 1999). Namely, Step I Seal of Pt microwire (Fig. 3.16a). The Pt microwire with 50 pm diameter was mounted in a glass capillary, which was drawn to a fine point using a pipette puller with 3-5 mm microwire protruded from the tip of glass capillary. Step II Etching Pt microwire (Fig. 3.16b). The protruded Pt wire was electrochemically etched by applying 1.2 V potential between the Pt wire and the counter electrode. The etching procedure was finished when the current decreased to zero. Step III Microwire insulation (Fig. 3.16c). Insulating paint... 

Microneedle puller micromanipulator and needle holder inverted microscope, preferentially equipped with both short (x 63 or X100) and long (x40) working distance phase objective lens glass capillaries ... 

An Agla micrometer syringe outfit, developed by the Wellcome Research Laboratories of England, is used for the injections. Needles can be pulled from glass capillary tubing with a Brinkman needle puller or by hand. These needles are placed over stainless steel needles and sealed with paraffin. The whole unit (micrometer, syringe, and needle) is then secured to a ring-stand with jaw clamps cushioned with foam rubber. 

PuU the fused segment of the capillary in a vertical pipet puller to produce two thinly drawn needles. 

Pull glass capillaries on a vertical or horizontal pipet puller to produce pipets with a fine tip, a long shaft, and a short shoulder (Note 10). 

FIGURE 2 Pulling the glass capillaries. (A) Glass tubes before pulling. (B) Partial view of the puller. (C) Capillary tip. Bar = 10 mm. 

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