Nicolet continuum ft ir microscope

In order to evaluate the morphology of inorganic nanoparticles and their distribution in the products, WNC and ANC were analyzed using Transmission Electron Microscopy (TEM, Philips CM200-FEG, Amsterdam, The Netherlands), operated at 200 kV. The samples for TEM analyses were prepared by depositing 1 drop of the NPs dispersions onto a carbon coated copper grid of 200 mesh.
The products, applied on glass slides and cured for 1 week, were characterized by micro-Fourier Transform Infrared Spectroscopy (µ-FTIR), using a Nicolet 6700 spectrophotometer coupled with Nicolet Continuum FTIR microscope (Thermo Fisher Scientific, Waltham, MA, USA) equipped with an MCT detector (acquired between 4000 and 600 cm⁻¹ with 128 acquisitions and 4 cm⁻¹ resolution), with a micro-compression diamond cell accessory. The spectra were baseline corrected using Omnic software. Then, they were normalized on the intensity of the Si–O stretching peak, at about 1100 cm⁻¹.
In order to characterize the rheological behavior of the products, a creep test was performed through a Bohlin CV0 120 Rheometer (Bohlin Instruments Vertriebs GmbH, Pforzheim, Germany) using a cone-plate configuration (1° angle, 40 mm diameter) with 0.03 mm gap. The measurements were conducted for 3 min under 1 Pa stress at 20 °C.

The surface charge of MPs with and without peptide conjugates was measured using a Zetasizer Nano ZS (Malvern Instruments, UK). For FTIR measurements, drop-cast films of MPs with and without peptide conjugates were analyzed using an FTIR microscope (Nicolet continuum FTIR microscope (Thermo Scientific). FTIR spectra were collected with a resolution of 4 cm⁻¹ and 128 scans of each sample. Conjugation of peptides to MPs was further analyzed through competitive labeling of MPs with 5-carboxytetramethylrhodamine alkyne (TAMRA-alkyne), 5-isomer fluorophore (Lumiprobe). Azide-functionalized MPs were conjugated first with targeting peptides and then labeled with TAMRA-alkyne fluorophore as described before in the conjugation section. Since the azide groups on the surface of MPs had already interacted with the alkyne group of peptides, they were expected to be non- (or less-) labeled compared to control particles (without peptide conjugates).