Laser-assisted surgery based on multiphoton absorption of near-infrared laser light has great potential for high precision surgery at various depths within the cells and tissues. Clinical applications include refractive surgery (fs-LASIK). The non-contact laser method also supports contamination-free cell nanosurgery. In this paper we describe usage of an ultrashort femtosecond laser scanning microscope for sub-100 nm surgery of human cells and metaphase chromosomes. A mode-locked 85 MHz Ti:Sapphire laser with an M-shaped ultrabroad band spectrum (maxima: 770 nm/830 nm) and an in situ pulse duration at the target ranging from 12 fs up to 3 ps was employed. The effects of laser nanoprocessing in cells and chromosomes have been quantified by atomic force microscopy. These studies demonstrate the potential of extreme ultrashort femtosecond laser pulses at low mean milliwatt powers for sub-100 nm surgery of cells and cellular organelles.
"The endo surgiclip instruments are commonly applied in surgical operations to repair biological defects, such as the anastomotic leakage in the gullet or gorge . Recent researches indicate the flexibility and adaptability of endoscopic surgiclip instruments in curative and healing operation . Endo surgiclip instruments can be applied in haemostasis using endoscopy to GI tract to repair the damaged tissues . "
[Show abstract][Hide abstract] ABSTRACT: Endo surgiclip instrument is the biomedical instrument that can be applied for endoscopic surgery to assist surgeons in homeostasis and secure mucosal gap surfaces during surgical operations. Since some clinic feedbacks show the surgiclip drop-off incidents which can potentially sever organ and tissue, the improvement of endo surgiclip instrument has been made in these years. Since few research papers were involved in the study of endo surgiclip instrument performance via mathematical modeling and computational simulation, currently some instrumental modifications are mainly based on clinic lab tests which prolong the improvement cycle and increase additional manufacturing cost. This paper introduces a new biomedical surgiclip instrument based on mathematical modeling, computer-aided simulation, and prototype testing. The analytic methodology proposed in this paper can help engineers in biomedical industry develop and improve biomedical instrument. Compared to the current conventional surgiclip instruments, this new surgiclip instrument can properly assist surgeon in surgical procedure with less operational force and no surgiclip drop-off incident. The prototype has also been built and tested. Both computational simulation and prototype testing show close results which validate the feasibility of this newly developed endo surgiclip instrument and the methodologies of mathematical modeling based computational simulation proposed in this paper.
[Show abstract][Hide abstract] ABSTRACT: Extremely short near infrared laser pulses (e.g. 10 fs) offer the
possibility of precise sub-100nm processing without collateral side
effects. Furthermore, the can be employed to excite a variety of
absorbers simultaneously due to their broad 100 nm emission band. We
demonstrate two-photon fluorescence imaging of green and red fluorescent
proteins in living cells as well as two-photon nanolithography with 12
fs laser pulses (750-850 nm) at low microwatt mean power using an 85 MHz
laser resonator. At a minimum of 400 μW mean power, direct
nanoprocessing in blood cells was realized. Multiphoton ablation in
biological specimens follows a P2/τ relation. We were
able to create sub-100nm ripples in silicon wafers, to cut glass, gold,
and polymers as well as to create transient nanoholes in the membranes
of living stem cells and cancer cells for targeted transfection.
Proceedings of SPIE - The International Society for Optical Engineering 02/2012; DOI:10.1117/12.908284 · 0.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The use of ultrashort femtosecond pulsed lasers to effect membrane permeabilisation and initiate both optoinjection and transfection of cells has recently seen immense interest. We investigate femtosecond laser-induced membrane permeabilisation in mammalian cells as a function of pulse duration, pulse energy and number of pulses, by quantifying the efficiency of optoinjection for these parameters. Depending on pulse duration and pulse energy we identify two distinct membrane permeabilisation regimes. In the first regime a nonlinear dependence of order 3.4-9.6 is exhibited below a threshold peak power of at least 6 kW. Above this threshold peak power, the nonlinear dependence is saturated resulting in linear behaviour. This indicates that the membrane permeabilisation mechanism requires efficient multiphoton absorption to produce free electrons but once this process saturates, linear absorption dominates. Our experimental findings support a previously proposed theoretical model and provide a step towards the optimisation of laser-mediated gene delivery into mammalian cells.
Jingjie Ding, Zuoye Liu, Shaohua Sun, Yanchao Shi, Bitao Hu
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