ABSTRACT
INTRODUCTION: The aim of this study was an analysis of the feasibility of a picosecond infrared laser fiber-assisted sclerostomy (PIRL-FAST) using a novel sapphire fiber and different energy levels of the picosecond laser. METHOD: The laser-assisted sclerostomy was carried out with a newly generated sapphire fiber of the PIRL-HP2-1064 OPA-3000 (Attodyne, Canada). Immediately after the intervention, the eyes were fixed in phosphate-buffered 3.5% formaldehyde. For subsequent histological analysis the eyes were cut into 4⯵m thick sections and stained with hematoxylin and eosin (H&E, Merck, Darmstadt, Germany). All preparations were then scanned and digitalized using the MIRAX SCAN (Carl Zeiss Microimaging GmbH, Jena, Germany). RESULTS: The pulse energies 150 µJ (Nâ¯= 4), 175 µJ (Nâ¯= 6), 200 µJ (Nâ¯= 7) and 250 µJ (Nâ¯= 6) were selected. Within the framework of this first feasibility analysis 400⯵m (10 sequential sections) of the sclerotomies were evaluated. The mean area of PIRL-FAST showed a dependency on the pulse energy applied. The diameter of the collateral damage zone (CDZ) depended on the pulse energy used. The largest CDZ could be measured using the highest pulse energy in this experiment (250⯵J). The environmental scanning electron microscope (ESEM) results revealed circular smooth sclerostomy wall with only minimal change of tissue ultrastructure. CONCLUSION: The PIRL-FAST using sapphire fibers is a new minimally invasive instrument to provide robust stenting from the anterior chamber to the subconjunctival space. Since the PIRL has proven to work efficiently in sectioning several tissues with minimal collateral damage these first proof of principle experiments might pave the way for a new minimally invasive glaucoma surgery strategy. We have already initiated experiments to analyze the wound healing and scar formation in vivo.
Subject(s)
Laser Therapy , Sclerostomy , Cicatrix , Germany , Humans , LasersABSTRACT
Posttranslational modifications and proteolytic processing regulate almost all physiological processes. Dysregulation can potentially result in pathologic protein species causing diseases. Thus, tissue species proteomes of diseased individuals provide diagnostic information. Since the composition of tissue proteomes can rapidly change during tissue homogenization by the action of enzymes released from their compartments, disease specific protein species patterns can vanish. Recently, we described a novel, ultrafast and soft method for cold vaporization of tissue via desorption by impulsive vibrational excitation (DIVE) using a picosecond-infrared-laser (PIRL). Given that DIVE extraction may provide improved access to the original composition of protein species in tissues, we compared the proteome composition of tissue protein homogenates after DIVE homogenization with conventional homogenizations. A higher number of intact protein species was observed in DIVE homogenates. Due to the ultrafast transfer of proteins from tissues via gas phase into frozen condensates of the aerosols, intact protein species were exposed to a lesser extent to enzymatic degradation reactions compared with conventional protein extraction. In addition, total yield of the number of proteins is higher in DIVE homogenates, because they are very homogenous and contain almost no insoluble particles, allowing direct analysis with subsequent analytical methods without the necessity of centrifugation. BIOLOGICAL SIGNIFICANCE: Enzymatic protein modifications during tissue homogenization are responsible for changes of the in-vivo protein species composition. Cold vaporization of tissues by PIRL-DIVE is comparable with taking a snapshot at the time of the laser irradiation of the dynamic changes that occur continuously under in-vivo conditions. At that time point all biomolecules are transferred into an aerosol, which is immediately frozen.
