ABSTRACT
In this article we describe the integration of impedance spectroscopy (EIS) and surface plasmon resonance (SPR) into one surface analytic device. A polydimethylsiloxane (PDMS) flow cell is created, matching the dimensions of a commercially available sensor chip used for SPR measurements. This flow cell allowed simultaneous measurements between an EIS and a SPR setup. After a successful integration, a proof of principle study was conducted to investigate any signs of interference between the two systems during a measurement. The flow cell was rinsed with 10 mM Tris-HCl and 1× PBS buffer in an alternating manner, while impedance and shifts of the resonance angle were monitored. After achieving a successful proof of principle, a usability test was conducted. It was assessed whether simultaneous detection occurred when: (i) Protein A is adsorbed to the gold surface of the chip; (ii) The non-occupied zone is blocked with BSA molecules and (iii) IgG1 is bound to the Protein A. The results indicate a successful merge between SPR and EIS.
ABSTRACT
Fluorescent cellular biomarkers play a prominent role in biosciences. Most of the available biomarkers have some drawbacks due to either physical and optical or cytotoxic properties. In view of this, we investigated the potential of green fluorescent nanodiamonds as biomarkers in living cells. Nanodiamonds were functionalized by attaching antibodies that target intracellular structures such as actin filaments and mitochondria. Then, the nanodiamond conjugates were transfected into HeLa cells. Transfections were mediated by 4(th)-generation dendrimers, cationic liposomes and protamine sulfate. Using fluorescence microscopy, we confirmed successful transfections of the nanodiamonds into HeLa cells. Nanodiamond fluorescence could be easily differentiated from cellular autofluorescence. Furthermore, nanodiamonds could be targeted selectively to intracellular structures. Therefore, nanodiamonds are a promising tool for intracellular assays.
Subject(s)
Diamond/analysis , Fluorescent Dyes/analysis , Immunoconjugates/chemistry , Immunoconjugates/metabolism , Mitochondria/metabolism , Molecular Probe Techniques , Nanoparticles/analysis , Actins/immunology , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Carbodiimides/chemistry , Dendrimers/chemistry , Diamond/chemistry , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Liposomes/chemistry , Microscopy, Fluorescence , Mitochondrial Proteins/immunology , Nanoparticles/chemistry , Particle Size , Protamines/chemistry , Spectrometry, Fluorescence , Spectrophotometry, Infrared , Static Electricity , Succinimides/chemistry , Surface PropertiesABSTRACT
We report 4 cases of ischemic brain and spinal cord injury after shoulder surgery in the beach chair position, using data from medical legal case reviews. We argue that the correlation between cardiovascular risk factors and cerebral ischemic complications for this type of surgery is poor in these middle-aged patients. Rather, our analysis suggests that the sitting position and the head position create specific physiological conditions that may be conducive to cerebral and spinal cord ischemia during this type of surgery. Thromboembolic events may be an additional cause of adverse neurologic outcomes.
