Real-time optical measurement of biologically relevant thermal damage in tissue-mimicking hydrogels containing bovine serum albumin.

Purpose: In controlled laboratory studies of hyperthermia and thermal ablation, translucent hydrogels containing bovine serum albumin (BSA) are often employed as tissue-mimicking materials due to the change in their opacity that takes place as they accumulate heat damage. In this work we demonstrate the biological relevance of this optical metric of thermal damage, as well as establish the physical mechanisms that link it with quantifiable damage to the proteins embedded in the gel.

Materials And Methods: We applied Fourier transform infrared (FTIR) spectroscopy, turbidity analysis using ultraviolet-visible (UV/VIS) spectroscopy, and size exclusion chromatography (SEC) to samples of heat-treated, aqueous bovine serum albumin (BSA).

Spray-freeze-drying of nanosuspensions: the manufacture of insulin particles for needle-free ballistic powder delivery.

The feasibility of preparing microparticles with high insulin loading suitable for needle-free ballistic drug delivery by spray-freeze-drying (SFD) was examined in this study. The aim was to manufacture dense, robust particles with a diameter of around 50 microm, a narrow size distribution and a high content of insulin. Atomization using ultrasound atomizers showed improved handling of small liquid quantities as well as narrower droplet size distributions over conventional two-fluid nozzle atomization.

Implementation of an FTIR calibration curve for fast and objective determination of changes in protein secondary structure during formulation development.

The aim of this study was to develop a quick and objective method for the determination of changes in protein secondary structure by Fourier transform infrared spectroscopy (FTIR). Structural shifts from native regions (alpha-helix, intramolecular beta-sheet) to aggregated strands (intermolecular beta-sheet) were used to evaluate protein damage. FTIR spectra of 16 different proteins were recorded and quantified by peak fitting of the non-deconvolved and baseline corrected amide I bands.