Hydration of hydrogels studied by near‐infrared hyperspectral imaging

Abstract

Hydrogels are an important class of biomaterials that can absorb large quantities of water. In this study, changes in hydration of natural hydrogels (agar, chitosan, gelatin, starch, and blends of each with chitosan) during storage and rehydration were studied by using near-infrared hyperspectral imaging (NIR-HSI). Moisture content was calculated based on changes in sample weight during hydration. The NIR-HSI data were acquired by using a push-broom system operating in diffuse reflectance in the wavelength range 943 to 1650 nm. A novel synthesis method was developed to enable common preparation of each hydrogel. Mean spectra obtained from the hyperspectral images were analyzed, and predictive models for moisture content were developed by using partial least squares regression. Models were compared in predictive performance by using an independent validation set of data. The optimal model in predictive performance was a 1 latent variable partial least squares regression model developed on second derivative and mean centered pseudoabsorbance data in the wavelength range 943 to 1272 nm. This model was applied to pixel spectra from samples in the validation set to inspect spatial variations during dehydration and rehydration. Challenges associated with NIR-HSI of hydrogels with a large variation in moisture content are discussed.

VIII Italian Symposium on Near Infrared Spectroscopy – NIRItalia 2018

“…In her keynote, three case studies were proposed in which the use of near infrared hyperspectral imaging (NIR-HSI), associated with appropriate chemometric approaches, proved to be effective for the characterization of biomaterials including hydrogels and sodium caseinate. 1,2 The session was then enriched by five oral presentations reporting hyperspectral imaging applications in various fields, covering forensic science (identification of particular biological traces on the crime scene), shelflife and storage studies of different fresh products, and proposals of great actual interest in the ecology and the environmental field.…”

“…In her keynote, three case studies were proposed in which the use of near infrared hyperspectral imaging (NIR-HSI), associated with appropriate chemometric approaches, proved to be effective for the characterization of biomaterials including hydrogels and sodium caseinate. 1,2…”