Selenium pellets

All DNA oligonucleotides were purchased from IDT Technologies. Progesterone (PRG), cholesterol (CHL), cortisol (CRT), aldosterone (ALD), estrone (ESN), 5β-pregnane-3ɑ,20-ɑ-diol (PRE), 5β-pregnane-3ɑ,20-ɑ-diol-glucuronide (PRE-Glu), and lysozyme were bought from Sigma Aldrich. Artificial urine DIN EN1616:199 was bought from Pickering Laboratories. RNAprotect Bacteria Reagent was bought from Qiagen. Proteinase K was bought from Roche.
Cadmium oxide (CdO; 99.95%, Alfa Aesar), sulfur (99.95%, ACROS Organics), 1-octadecene (ODE; 90% ACROS Organics), and oleylamine (80–90%) were bought from Fisher Scientific and used as purchased. Zinc acetate (Zn(Ac)₂, 99.99%), selenium pellets (Se, 99.99%), trioctylphosphine (TOP, 97%), trioctylphosphine oxide (TOPO, 99%), oleic acid (OA, 90%), poly(isobutylene-alt-maleic anhydride)–6000 g mol⁻¹ (PIMA), (2-aminoethyl)trimethylammonium chloride, histamine, triethylamine, and HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) were obtained from Sigma-Aldrich. HPLC-grade solvents including hexanes (Fisher Scientific), methanol (Honeywell), anhydrous dimethyl sulfoxide (Sigma Aldrich) and chloroform (J.T. Baker) were bought and used without further purification. HEPES 1× is a solution of 25 mM of HEPES and 150 mM of NaCl, adjusted to pH 7.6.

Transition metal chalcogenides were synthesised in a hot-wall quartz tube reactor under low-pressure conditions. The chamber was flushed three times with argon (Ar), and the samples were subsequently heated to 850 °C under 100 sccm Ar. The samples were annealed at this temperature for 30–60 min, and growth was subsequently carried out for 10–15 min by exposing the samples to volatised chalcogen X vapours. The vapours were generated by heating solid chalcogen precursors situated upstream from the samples: ~110 °C for sulphur (sulphur flakes; Sigma Aldrich), ~220 °C for selenium (selenium pellets; Sigma Aldrich), and ~420 °C for tellurium (tellurium pieces; Sigma Aldrich). After growth, the samples were naturally cooled to room temperature under 100 sccm Ar flow. Synthesis of continuous MoS₂ films for electrical device measurements was achieved by increasing the growth temperature to 950 °C.
Identical processing conditions were used to synthesise transition metal nitrides in a cold-wall reactor (AIXTRON Black Magic), except that the entire process was done under 100 sccm H₂ flow instead of argon in order to mitigate surface oxidation of the alloys. The growth of nitrides was performed by introducing 5 sccm NH₃ into the chamber for 5 min The samples were then naturally cooled down to room temperature under 100 sccm H₂.

All reagents were used as purchased from the
manufacturer without further purification. The following were purchased
from Sigma-Aldrich: trioctylephosphine (TOP; cat: 718165), selenium
pellets (Se; cat: 209643), diphenylphosphine (DPP; cat: 252964), cadmium
oxide (CdO; cat: 202894), trioctylphosphine oxide (TOPO; cat: 223301),
1-hexadecylamine (HDA; cat: 445312), tetradecylphosphonic acid (TDPA;
cat: 736414).