Hi folks. You may remember that in March of this year, I posted a suggestion that we all get together to convince Bangs Laboratories to make some custom microspheres that we could use for defining point spread functions in our instruments. It worked, and the beads are now ready to purchase. The company wanted me to write this quick note to notify all those who are interested to contact the company Bangs Laboratories, Inc. 317-844-7176 voice 317-575-8801 fax [log in to unmask] I suggest that everyone first ask for their TECH. NOTE #56. It contains information about the individual beads (three types are available), including spectra. It also contains some info and results which came out of a "pre-release" set of beads which the company sent me so that I could appraise them. The best people to contact directly are either Mary Meza ([log in to unmask]) or Brian Bromberek ([log in to unmask]) I think the company has done a reasonsible and excellent job in producing these beads, and I hope everyone finds them useful. I have absolutely NO financial interest in this deal, but let me give you a quick run-thru about the beads..... They are pretty cheap. $65 will buy a single vial of beads containing 1 ml suspended in water. A few microliters are all you need (diluted into your suspension or embedding medium of choice) for your analysis. They will last a while.... They are suprisingly bright. My LSM410 had no problems imaging them. I think even older instruments (e.g. MRC-600) should have no problems getting high quality images. The dye is trapped inside the bead, so there are lots of molecules to excite in these 63nm beasties. These are single-label beads, each useful for a limited set of excitation wavelengths. One is excited by 350-380nm to emit at a peak of 410nm (half maximal emission about 445nm). A second bead is excited most efficiently by 480-540nm and emits at a peak of 570 (half maximal emission aobut 600nm: utility for 568nm untested so far). The third bead is excited by 630-660 and emits at a peak of 700 (half maximal emission about 710). I tested them with Uv-Ar (351/364), visible Ar (488), Green HeNe (543) and Red HeNe (633). The only weak point was using the weak green HeNe Laser, which did not overly impress me with the image brightness for the second bead. I think the beads are more useful than just for point spread function determination. I think they can also help for detecting mis-alignment of optical elements (if the XZ images of the PSF is skewed/slanted), and for determining z-axis registration of different laser lines (if a mix of the beads settled onto a glass coverslip does not produce images which coincide at the same z-axis position in response to multiple laser excitation). Based on work with these beads, our faithful Zeiss tech is coming out to check our UV laser alignment... So that's it for now. If the company gets enough sales from this round, maybe we can torture them again and get them to make a "mixed dye" bead that combines all the different dyes into one bead, or to make other beads if other laser lines/wavelengths need to be hit. Let them know what you want, they are pretty receptive to new ideas. Enjoy. Chip *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* Chip Montrose Johns Hopkins University tel: 410-955-9681 Ross 930 FAX: (410) 955-9677 720 Rutland Avenue email: [log in to unmask] Baltimore, MD 21205 *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*