Glass microneedles

Besides AFM based SMFS, there are several other nanotechnologies which have also been used to measure the minute force in molecular scale, including magnetic beads [6], optical tweezers [7], glass microneedles [8], and biomembrane force probe [9]. These different methods can offer force signals with different timescale and sensitivity. The AFM based SMFS becomes popularized in single polymer chain experiment, because it is relatively easy to be handled. Till now, many elegant experiments have been... 

A variety of different methods that allow one to directly study forces between few or individual molecules or functional groups relevant to supramolecular chemistry have been developed and refined in the past decades. These techniques include, among others, magnetic beads, optical tweezers, glass microneedles, the biomembrane force probe," force clamp, and AFM approaches. For a recent overview, the reader is referred to the review by Clausen-Schaumann et al, who summarized and compared these prominent methods in detail. As shown in Table these techniques enable the measurement of forces that range from weak entropic forces at several piconewtons to the rupture of covalent bonds at a few nanonewtons covering a dynamic range from microseconds to seconds. 

Manipulation of these biomoleeules ean be eonducted by using a glass-microneedle (Ishijima e/a/, 1996). Many studies, however, have used laser trapping of microbeads by optical tweezers, where a single molecule is attached to a microbead (Prasad, 2003). 

PAHs adsorbed on particles of carbon black were also photostabilized (Behymer and Hites, 1988). However, Barofsky and Baum (1976) demonstrated that BaP, anthracene, BaA, and pyrene deposited on carbon microneedle field desorption emitters and exposed to UV radiation were all photooxidized to carbonyl compounds. Similarly, PAHs can photodegrade efficiently in air when adsorbed to substrates of silica gel, alumina, or glass plates (e.g., see Lane and Katz, 1977 Kormacher et al., 1980 Behymer and Hites, 1985 Yokely et al., 1986). 

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 ... 

Fig. 12.1. Manipulation of molecular motors and step movement of myosin 11. (a) Manipulation of a single-myosin molecule with a microneedle. A myosin molecule captured at a tip of the microneedle is allowed to interact with an actin filament placed on a glass surface, (b) Manipulation of an actin filament by a laser trap. Two beads attached at both ends of an actin filament are trapped by a laser. The actin filament is manipulated to interact with myosin molecules on the filament placed on a glass surface, (c) Nonprocessive movement of myosin 11. (Top) The displacement of the microneedle attached to single myosin 11 head (SI) was measured as a function of time and the binding of myosin to actin was measured by stiffness calculated from the displacement record (bottom), (d) Expansion of the rising phase of the displacement record above...

---