scholarly journals Synthesis and characterization of theranostic agents for photoacoustic imaging and therapy.

Author(s):  
Yan Jie Wang

In this work, phase-change contrast agents were developed for photoacoustic (PA) imaging and therapy. They consist of superheated liquid perfluorocarbon and gold nanoparticles capped by a Poly-(Lactide-co-Glycolic Acid) (PLGA) polymer shell. The phase transition from liquid to gas bubble can be remotely triggered by a laser source. In their liquid state, upon laser irradiation, these agents generated strong PA signals which were proportional to the laser fluence and particle sizes. The vaporization threshold decreased with increasing particle size, and was 850, 670 and 420 mJ/cm2 for 2, 5, 10 μm-sized PLGA particles loaded with 35 nm GNPs, respectively. Cell culture studies, including passive uptake by the cancer cells and mechanical damage to the cancer cells caused by the vaporization inside the cells are also investigated. These agents show potential as photoacoustic imaging contrast and cancer therapy agents for clinical applications.

2021 ◽  
Author(s):  
Yan Jie Wang

In this work, phase-change contrast agents were developed for photoacoustic (PA) imaging and therapy. They consist of superheated liquid perfluorocarbon and gold nanoparticles capped by a Poly-(Lactide-co-Glycolic Acid) (PLGA) polymer shell. The phase transition from liquid to gas bubble can be remotely triggered by a laser source. In their liquid state, upon laser irradiation, these agents generated strong PA signals which were proportional to the laser fluence and particle sizes. The vaporization threshold decreased with increasing particle size, and was 850, 670 and 420 mJ/cm2 for 2, 5, 10 μm-sized PLGA particles loaded with 35 nm GNPs, respectively. Cell culture studies, including passive uptake by the cancer cells and mechanical damage to the cancer cells caused by the vaporization inside the cells are also investigated. These agents show potential as photoacoustic imaging contrast and cancer therapy agents for clinical applications.


Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).


Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3645
Author(s):  
Isabel Theresa Schobert ◽  
Lynn Jeanette Savic

With the increasing understanding of resistance mechanisms mediated by the metabolic reprogramming in cancer cells, there is a growing clinical interest in imaging technologies that allow for the non-invasive characterization of tumor metabolism and the interactions of cancer cells with the tumor microenvironment (TME) mediated through tumor metabolism. Specifically, tumor glycolysis and subsequent tissue acidosis in the realms of the Warburg effect may promote an immunosuppressive TME, causing a substantial barrier to the clinical efficacy of numerous immuno-oncologic treatments. Thus, imaging the varying individual compositions of the TME may provide a more accurate characterization of the individual tumor. This approach can help to identify the most suitable therapy for each individual patient and design new targeted treatment strategies that disable resistance mechanisms in liver cancer. This review article focuses on non-invasive positron-emission tomography (PET)- and MR-based imaging techniques that aim to visualize the crosstalk between tumor cells and their microenvironment in liver cancer mediated by tumor metabolism.


2020 ◽  
Vol 401 (10) ◽  
pp. 1153-1165 ◽  
Author(s):  
Antônio F. da Silva Filho ◽  
Lucas B. Tavares ◽  
Maira G. R. Pitta ◽  
Eduardo I. C. Beltrão ◽  
Moacyr J. B. M. Rêgo

AbstractPancreatic ductal adenocarcinoma is one of the most aggressive tumors with a microenvironment marked by hypoxia and starvation. Galectin-3 has been evaluated in solid tumors and seems to present both pro/anti-tumor effects. So, this study aims to characterize the expression of Galectin-3 from pancreatic tumor cells and analyze its influence for cell survive and motility in mimetic microenvironment. For this, cell cycle and cell death were accessed through flow cytometry. Characterization of inside and outside Galectin-3 was performed through Real-Time Quantitative Reverse Transcription PCR (qRT-PCR), immunofluorescence, Western blot, and ELISA. Consequences of Galectin-3 extracellular inhibition were investigated using cell death and scratch assays. PANC-1 showed increased Galectin-3 mRNA expression when cultivated in hypoxia for 24 and 48 h. After 24 h in simultaneously hypoxic/deprived incubation, PANC-1 shows increased Galectin-3 protein and secreted levels. For Mia PaCa-2, cultivation in deprivation was determinant for the increasing in Galectin-3 mRNA expression. When cultivated in simultaneously hypoxic/deprived condition, Mia PaCa-2 also presented increasing for the Galectin-3 secreted levels. Treatment of PANC-1 cells with lactose increased the death rate when cells were incubated simultaneously hypoxic/deprived condition. Therefore, it is possible to conclude that the microenvironmental conditions modulate the Galectin-3 expression on the transcriptional and translational levels for pancreatic cancer cells.


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