Benefits of Microwave-Assisted Processing Go
Beyond Time Savings
Richard T. Giberson
1
* and Mark A. Sanders
2
1
Research and Development, Ted Pella, Inc., 4595 Mountain Lakes Blvd., Redding, CA 96003
2
Imaging Center, Univ. of MN, 23-37 Snyder Hall, 1475 Gortner Ave., St. Paul, MN 55108
*
msanders@umn.edu
Introduction
was the important step in beginning to better understand
Microwave-assisted processing of biological specimens, from
microwave methods [2]. The precise method of activation that
its inception, has been a methodology that promised time
microwave radiation contributes to the acceleration of a wide
savings over conventional processing methods [1]. It has
range of processing applications is unknown. However, with
taken almost 30 years to define and control the significant
the advent of a better understanding of what appears to be the
variables associated with microwave processing [2]. Recent
real variables associated with microwave-assisted processes, the
research combined with improved technology have helped in
quality of the final product has been improved. This knowledge
the identification and control of the experimental variables
has led to better techniques and experimental results for the
associated with microwave-assisted processing [2-7]. Stated
following processes: tissue processing for electron microscopy
simply they are: (1) constant sample temperature control in
(EM) [2], immunolabeling [3], formaldehyde fixation [4], and
conjunction with continuous microwave irradiation [3-4],
decalcification [5]. As a result the role of temperature in the
(2) control of wattage in the microwave device (the ability to
form of microwave-induced sample heating appears to have a
reduced or insignificant role in overall protocol design.
control microwave power in the same manner as a dimmer
switch controls a light) [2-5], and (3) energy uniformity in the Materials and Methods
microwave cavity [3-4]. The distinct advantage of knowing the true wattage and
Understanding the energy/heat dichotomy, we believe, a uniform microwave environment is that the chemistry used
Figure 1: (A-B) Electron micrographs of liver fixed in 10% neutral buffered formalin by conventional and microwave methods. Tissues were fixed conventionally for 3
hours at room temperature. Note the extraction and absence of organelles. (C-D) Tissues were fixed with microwave radiation for 15 minutes at 150 W followed by 5
minutes at 650W. Note the greatly improved ultrastructure [2].
28 doi: 10.1017/S1551929509000340
www.microscopy-today.com • 2009 September
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76