Macro ATR-FTIR spectroscopic
imaging was performed using a Tensor 27 spectrometer (Bruker, U.K.)
coupled to an IMAC large sample compartment (Bruker, U.K.) and a single
reflection variable angle ATR accessory (Pike Technologies, Madison,
WI) or a fixed angle of incidence (45°) accessory with a heated
ZnSe internal reflection element (IRE) (Specac). The IRE was heated
to the desired temperature with a nichrome-wire-based heating controller.
An MCT FPA detector with 64 × 64 pixels was employed, with a
pixel size of 40 × 40 μm2. With this setup,
4096 spectra were recorded simultaneously in the continuous scan mode
over the range of 900–3900 cm–1. Spectra
were recorded by coadding 32 scans at a resolution of 4 cm–1. For the flow setup, a PDMS channel of dimensions 7 mm × 2
mm × 1 mm was held in position and secured onto the ZnSe IRE
by using a PMMA top plate. The channel was connected to a syringe
with needle (inlet) and waste container (outlet) with PTFE tubing
with a 0.5 mm inner diameter. The syringe was then placed in a syringe
pump (Harvard Apparatus) with the flow controlled at 10 μL/min.
An overview of the experimental setup is presented inFigure S1 . For the static experiments, the same
setup was used, but the syringe containing the buffer or IgG sample
was not connected to the pump.
imaging was performed using a Tensor 27 spectrometer (Bruker, U.K.)
coupled to an IMAC large sample compartment (Bruker, U.K.) and a single
reflection variable angle ATR accessory (Pike Technologies, Madison,
WI) or a fixed angle of incidence (45°) accessory with a heated
ZnSe internal reflection element (IRE) (Specac). The IRE was heated
to the desired temperature with a nichrome-wire-based heating controller.
An MCT FPA detector with 64 × 64 pixels was employed, with a
pixel size of 40 × 40 μm2. With this setup,
4096 spectra were recorded simultaneously in the continuous scan mode
over the range of 900–3900 cm–1. Spectra
were recorded by coadding 32 scans at a resolution of 4 cm–1. For the flow setup, a PDMS channel of dimensions 7 mm × 2
mm × 1 mm was held in position and secured onto the ZnSe IRE
by using a PMMA top plate. The channel was connected to a syringe
with needle (inlet) and waste container (outlet) with PTFE tubing
with a 0.5 mm inner diameter. The syringe was then placed in a syringe
pump (Harvard Apparatus) with the flow controlled at 10 μL/min.
An overview of the experimental setup is presented in
setup was used, but the syringe containing the buffer or IgG sample
was not connected to the pump.