Laser speckle contrast imaging for monitoring of acutepancreatitis at ischemia-reperfusion injury of thepancreas in rats

The influence of ischemia-reperfusion(I/R)action on pancreatic blood flow(PBF)and the development of acute pancreatitis(AP)in laboratory rats is evaluated in vivo by using the laser speckle contrast imaging(LSCI).Additionally,the optical properties in norm and under condition of AP in rats were assessed using a modied integrating sphere spectrometer and inverse Monte Carlo(IMC)software.The results of the experimental study of microcirculation of the pancreas in 82 rats in the ischemic model are presented.The data obtained conrm the fact that local ischemia and changes in the blood°ow velocity of the main vessels cause and provoke acute pancreatitis.

A pilot study of the dynamics of tissue oxygenation in vivo using time-resolved phosphorescence imaging

Oxygenation of tissues plays an important role in the development and progression of tumor to treatment effects.Method of metalloporphyrines phosphorescence quenching by oxygen is one of the ways to measure dynamics of the oxygen concentration in the tissues by phosphorescence lifetime imaging of meso-tetra(sulfophenyl)tetrabenzoporphyrin Pd(Ⅱ)(TBP)using the time-correlated single photon counting(TCSPC)method.It has been shown that phosphorescence lifetime of the sensor in S37 tumor in vivo varied in the range of 130 to 290μs after both topical and intravenous administration of TBP.It indicates that oxygen level in tumors was lower compared to normal tissues where TBP phosphorescence has not been detected.Phosphorescence lifetimes of TBP increased in the solid tumor and in the muscle after photodynamic therapy of solid tumor that demonstrates oxygen consumption during treatment and possibly stopping the blood flow and hence the oxygen supply to the tissues.

Effect of poly(3-hydroxyalkanoates) as natural polymers on mesenchymal stem cells

Mesenchymal stem cells(MSCs)are stromal multipotent stem cells that can differentiate into multiple cell types,including fibroblasts,osteoblasts,chondrocytes,adipocytes,and myoblasts,thus allowing them to contribute to the regeneration of various tissues,especially bone tissue.MSCs are now considered one of the most promising cell types in the field of tissue engineering.Traditional petri dish-based culture of MSCs generate heterogeneity,which leads to inconsistent efficacy of MSC applications.Biodegradable and biocompatible polymers,poly(3-hydroxyalkanoates)(PHAs),are actively used for the manufacture of scaffolds that serve as carriers for MSC growth.The growth and differentiation of MSCs grown on PHA scaffolds depend on the physicochemical properties of the polymers,the 3D and surface microstructure of the scaffolds,and the biological activity of PHAs,which was discovered in a series of investigations.The mechanisms of the biological activity of PHAs in relation to MSCs remain insufficiently studied.We suggest that this effect on MSCs could be associated with the natural properties of bacteria-derived PHAs,especially the most widespread representative poly(3-hydroxybutyrate)(PHB).This biopolymer is present in the bacteria of mammalian microbiota,whereas endogenous poly(3-hydroxybutyrate)is found in mammalian tissues.The possible association of PHA effects on MSCs with various biological functions of poly(3-hydroxybutyrate)in bacteria and eukaryotes,including in humans,is discussed in this paper.

CONFORMATION STUDY OF THE LARGE FRAGMENT OF E. COLI DNA POLYMERASE I BY STM

The large fragment of E.coli DNA polymerase I is imaged by scanning tunneling microscope. The specimen is deposited on highly oriented pyrolytic graphite surface, and then covered with pure paraffin oil in order to maintain hydration of the molecules. Images of the enzyme reveal an ellipsoid shape of 5.5-6.0nm wide and 7.0 -7.5 nm long. The conformation of the enzyme is in agreement with the model derived from X- ray crystallography studies.

SERS-based lateral flow immunoassay of troponin I by using gapenhanced Raman tags

The lateral flow immuno assay (LFIA) has emerged as a powerful tool for rapid scree ning owing to its simplicity and flexibility for detection of various biomarkers. However, conventional LFIA strips have several disadvantages, including limits in quantitative analysis and low sensitivity. Here we developed a novel surface-e nhanced Rama n scatteri ng LFIA based on non spherical gap-e nhanced Raman tags (GERTs), with Raman molecules (RMs) embedded in a 1-nm gap between Au nanorod core and Au shell. Such tags have a strong and uniform surface-enhanced Rama n scattering (SERS) resp on se, an order of mag nitude higher than that of other comm on SERS tags such as Au nano rods, nano stars, Au nano shells with surface-adsorbed RMs, or spherical GERTs with embedded RMs. The feasibility of the tags was dem on strated by the semiqua ntitative and sen sitive detecti on of the heart disease biomarker cardiac tropo nin I (cTnI). GERTs were conjugated with mono clonal antibodies and used for LFIA in the same way as ordinary functionalized colloidal gold. The presenee of the target antigen, cTnI, was identified by Raman microscopy mapping of the test zone. With the SERS-based LFIA, the limit of cTnI detection was about 0.1 ng/mL. This value is within the diagnostic range of cTnI in the blood serum of patients with heart infarction and is 30 times lower than that of the colorimetric LFIA test using the same antibodies and either GERTs or colloidal gold as labels.

Integrated binary hologram to monitor cargo release from a drug-eluting film

Nowadays,holography translates from a pure technical tool for recording the phase and amplitude of the light wave to a widely applicable research-based method.Holographic devices are used for security enhancement,entertainment,3D display technologies and augmented reality.Binary computer-generated holograms(amplitude or phase-based)are of specific interest.They are easy to compute and their manufacturing methods are fast and robust.In this work,a method of manufacturing amplitude-only binary holograms out of biopolymers films is proposed.Opaque cargo bits made out of different bioactive substances(antibiotics,dyes,etc.)absorb or scatter specific parts of the incoming light wave.Cargo release was conducted by submerging the produced holograms into the aqueous solution at specific pH and temperature levels.Drug elution from the film was traced out by the numerical analysis of the far-field diffraction pattern,which otherwise could only be measured post-factum using sophisticated spectroscopic or chromatography devices.This approach broadens the application of general holography over to the field of biomedical research relevant to quantitative monitoring of the drug elution.