O xylene

The process of polysilsesquioxane (PSQ) bonding is schematically
shown in Figure S1. The 4 in. SiO₂ wafer with micronanofluidic features and a 4 in. double-side-polished
borosilicate glass (175 μm thickness, Si-Mat Germany) were piranha
cleaned (3:1 concd H₂SO₄/H₂O₂, 150 °C) for 15 min. PSQ was freshly prepared before
bonding by mixing Hardsil (AP grade, Gelest Inc.) with O-xylene (Fisher
Scientific) in a 1:2 ratio. Then, PSQ was spin-coated (3000 rpm, 30
s) on piranha-cleaned borosilicate glass and cured at 220 °C
for 30 min. The SiO₂ wafer was first treated with O₂ plasma using RIE (Plasmatherm BatchTop, sccm O₂, 500 mT pressure, 100 W power, 1 min), and then the PSQ-coated side
of the borosilicate glass wafer was O₂ plasma treated (10
sccm O₂, 250 mT pressure, 50 W power, 2 min), and both
wafers were brought together to enable bonding. The bonded wafer was
then diced into individual chips.
After the particles had been
trapped, the chip was reopened using a tweezer to bend-off the lid
starting at a chip edge (Figure S2). The
chip was then coated with 3 nm carbon using a thermal evaporator before
SEM imaging. The SEM images were recorded at 15 kV acceleration voltage
and a working distance of 2 mm with an in-lens detector.

The chloro [5,10,15,20-tetraquis(pentafluorophenyl)porphyrinate] iron (III) [Fe(TPFPP)Cl] (FePF) was prepared by a literature procedure, in environmentally compatible conditions, using microwave heating [31 (link)]. Quinoline (98%), acridine (97%), and H₂O₂ 30% w/w were purchased from Sigma-Aldrich (St. Louis, MO, USA). o-Xylene (98%) n-hexane, and ethyl acetate were acquired from Fisher Scientific (Waltham, MA, USA). Ethanol was from AppliChem (Gatersleben, Germany). All solvents were p.a. grade. Nitric acid (65%) was from PanReac (Barcelona, Spain). The chromatographic purifications were carried out using silica gel 60 F254 from Merck (Darmstadt, Germany).