Fourier Transform Infrared Imaging Techniques Research Articles

Quantification of microplastic mass and removal rates at wastewater treatment plants applying Focal Plane Array (FPA)-based Fourier Transform Infrared (FT-IR) imaging

This paper presents a method for microplastic (MP) mass quantification using a Focal Plane Array-based Fourier Transform Infrared imaging technique. It discusses the issue that particle number is not a conserved base quantity and hence less suited than mass to compare independent studies on MP in the environment. It concludes that MP mass should be included when quantifying MP pollution in the environment, supplementing the conventional approach of reporting particle numbers. Applying mass as the unit of MP measurement, the paper presents data showing that Danish wastewater treatment plants discharge around 3 t/year of MP in the size range 10–500 μm. This value corresponds to an annual per capita emission from these plants of 0.56 g MP/(capita year). The distribution of polymer types by mass and particle number differed because the size of MP particles of the different material types varied.

Fourier Transform Infrared Spectroscopy and Imaging in Cancer Diagnosis and Characterization

Fourier Transform Infrared (FTIR) spectroscopy and imaging techniques are formidable, novel, rapid and non-destructive tools for characterization of different biological systems from molecules to membranes, cells and tissues. These techniques with multivariate analysis tools can be used in the diagnosis/follow-up of diseases including cancer, and in monitoring drug or chemical induced alterations in tissues and cells. In the current study, Attenuated Total Reflectance FTIR spectroscopy together with chemometric (cluster and principal component) analysis were utilized as a diagnostic tool for urinary bladder cancer while FTIR imaging technique was used in the clarification of sodium butyrate (NaB) induced-differentiation in colon cancer cells since butyrate has an anti-proliferative effect in colon cancer. For bladder cancer studies, bladder wash samples of bladder cancer and control groups were used directly for spectra collection. ATR-FTIR studies revealed significant alterations in lipid, protein, and nucleic acid content of bladder wash samples of cancer groups as compared to the control ones. Based on these spectral variations, bladder cancer group can be successfully differentiated from control via chemometric analysis with a higher sensitivity and specificity than many other methods used currently in bladder cancer diagnosis. In colon cancer study, aggressive CaCo2 cell lines were treated with 3mM NaB and cultured for 48h for complete differentiation. Specific band ratio analysis such as lipid/protein, glycogen/phosphate and RNA/DNA were calculated from the chemical maps of control and NaB-treated cells. Imaging results indicated the reconstruction of cancer induced changes in response to NaB treatment by modulating the saturated, unsaturated, triglyceride, protein and nucleic acid content in the treated cells. The findings of this study supported that FTIR spectroscopic and imaging techniques are valuable, label-free and sensitive bio-analytical tools for cancer diagnostics and investigating the global roles of drugs on cancer treatment.

Lathyrism-induced alterations in collagen cross-links influence the mechanical properties of bone material without affecting the mineral

In the present study a rat animal model of lathyrism was employed to decipher whether anatomically confined alterations in collagen cross-links are sufficient to influence the mechanical properties of whole bone.Animal experiments were performed under an ethics committee approved protocol. Sixty-four female (47day old) rats of equivalent weights were divided into four groups (16 per group): Controls were fed a semi-synthetic diet containing 0.6% calcium and 0.6% phosphorus for 2 or 4weeks and β-APN treated animals were fed additionally with β-aminopropionitrile (0.1% dry weight). At the end of this period the rats in the four groups were sacrificed, and L2–L6 vertebra were collected. Collagen cross-links were determined by both biochemical and spectroscopic (Fourier transform infrared imaging (FTIRI)) analyses. Mineral content and distribution (BMDD) were determined by quantitative backscattered electron imaging (qBEI), and mineral maturity/crystallinity by FTIRI techniques. Micro-CT was used to describe the architectural properties. Mechanical performance of whole bone as well as of bone matrix material was tested by vertebral compression tests and by nano-indentation, respectively.The data of the present study indicate that β-APN treatment changed whole vertebra properties compared to non-treated rats, including collagen cross-links pattern, trabecular bone volume to tissue ratio and trabecular thickness, which were all decreased (p<0.05). Further, compression tests revealed a significant negative impact of β-APN treatment on maximal force to failure and energy to failure, while stiffness was not influenced. Bone mineral density distribution (BMDD) was not altered either. At the material level, β-APN treated rats exhibited increased Pyd/Divalent cross-link ratios in areas confined to a newly formed bone. Moreover, nano-indentation experiments showed that the E-modulus and hardness were reduced only in newly formed bone areas under the influence of β-APN, despite a similar mineral content.In conclusion the results emphasize the pivotal role of collagen cross-links in the determination of bone quality and mechanical integrity. However, in this rat animal model of lathyrism, the coupled alterations of tissue structural properties make it difficult to weigh the contribution of the anatomically confined material changes to the overall mechanical performance of whole bone. Interestingly, the collagen cross-link ratio in bone forming areas had the same profile as seen in actively bone forming trabecular surfaces in human iliac crest biopsies of osteoporotic patients.