Dual-trap Raman tweezers for probing dynamics and heterogeneity of interacting microbial cells

Abstract

Abstract. We report on development of dual-trap Raman tweezers for monitoring cellular dynamics and heterogeneity of interacting living cells suspended in a liquid medium. Dual-beam optical tweezers were combined with Raman spectroscopy, which allows capturing two cells that are in direct contact or closely separated by a few micrometers and simultaneously acquiring their Raman spectra with an imaging CCD spectrograph. As a demonstration, we recorded time-lapse Raman spectra of budding yeast cells held in dual traps for over 40 min to monitor the dynamic growth in a nutrient medium. We also monitored two germinating Bacillus spores after the initiation with L-alanine and observed their heterogeneity in the release of CaDPA under identical microenvironment. C 2010 Society of Photo-Optical instrumentation Engineers.

Reconsolidation of a cocaine associated memory requires DNA methyltransferase activity in the basolateral amygdala

“…Rats (weighing 300–320 g at the time of surgery) were anesthetized with sodium pentobarbital anesthesia (60 mg/kg, i.p.). Catheters were inserted into the right jugular vein with the tip terminating at the opening of the right atrium as described 15 34 35 . Guide cannulae (23 gauge; Plastics One, Roanoke, VA) were implanted bilaterally 1 mm above the BLA [anterior/posterior (AP), −2.9 mm from bregma; medial/lateral (ML), ±5.0 mm from bregma; dorsal/ventral (DV), −8.5 mm below the skull surface] 23 25 .…”

“…The training method and conditions were modified from our previous studies 15 35 . The chambers (AniLab Software & Instruments, Ningbo, China) were equipped with two nosepoke operandi (AniLab Software & Instruments, Ningbo, China) located 9 cm above the floor of the chambers.…”

“…and transcardially perfused with paraformaldehyde. Cannula placements were assessed by Nissl’s staining of 40-μm thick coronal sections and examination under light microscopy 24 35 . The locations of representative cannula tips are shown in Fig.…”

Polarized Raman spectroscopic investigations on hemoglobin ordering in red blood cells

“…In one of the studies, 14 Raman spectra were recorded for two populations of RBCs; one having their equatorial planes normal to the beam propagation direction (population 1) and the other having their equatorial planes parallel to the beam propagation direction (population 2). Dual trap tweezers have been used to simultaneously investigate two optically trapped cells to probe the dynamics and heterogeneity of interacting microbial cells 17 and also to translate the trapped cell relative to the Raman excitation beam and thus acquire spatially resolved Raman spectrum 18 etc. In population 1, the RBCs had their equatorial planes parallel to the excitation beam polarization direction.…”

Multiple-trap laser tweezers Raman spectroscopy for simultaneous monitoring of the biological dynamics of multiple individual cells

“…Consequently, this technique becomes somewhat cumbersome when hour-long observations are desired and results from large numbers of cells are required. To improve the measurement efficiency of LTRS, we developed a dual-trap LTRS system for monitoring two closely separated cells, in which a single laser beam was separated into two beams with a beam splitter to form dual traps and two trapped cells were projected at the different locations on the entrance slit of an imaging spectrograph such that the Raman spectra of these two cells can be acquired simultaneously [12,18]. Multiple-beam optical traps or optical tweezers arrays have been developed [19,20] but have not yet been combined with Raman spectroscopy.…”