Potassium lactate

Experiments were carried out with Milli-Q water (18.2 MΩ·cm). Inorganic salts, hydrogen peroxide (30% solution), glucose, potassium lactate (60% solution), fructose, mannose, sodium gluconate, sodium tartrate, (3-aminopropyl)triethoxysilane (99%), and organic solvents were obtained from Sigma-Aldrich (Burlington, MA, USA) or Reachim (Moscow, Russia) at the highest purity. Perfluorosulfonated ionomer (PFSI) (10% solution in isopropyl alcohol), a structural analogue of Nafion, was obtained from Plastpolimer (St. Peterburg, Russia). Hydrochloric acid solutions were prepared from fixanals manufactured by Germed (Dresden, Germany).
Lactate oxidase (LOx, EC1.1.3.2) from Pediococcus species (Sorachim, Lausanne, Switzerland) was used in the form of a lyophilized protein with a declared activity of 32.8 U/mg. glucose oxidase (GOx, EC 1.1.3.4) from Aspergillus niger (Sigma-Aldrich, Burlington, MA, USA) was used in the form of a lyophilized protein with a declared activity of 246.6 U/mg. Standard samples of blood serum were obtained from Spinreact (Girona, Spain).

PBMCs were isolated using density gradient centrifugation (Histopaque, Ficol) from blood drawn from healthy donors (after obtaining informed consent and approval by the Institutional Ethics Committee and in accordance with the Declaration of Helsinki). For some experiments, human pDCs were also isolated from buffy coats collected from Tata Medical Centre Blood Bank, Kolkata, through an approved material transfer agreement, in concurrence with the institutional human ethics committee. PDCs were sorted from whole PBMCs by magnetic immunoselection, using anti-BDCA4 microbeads (Miltenyi Biotec, Germany) and cultured in 100 μl of complete RPMI media (GIBCO), at 37°C and 5% CO_2. pDCs in culture were treated as mentioned in the figure legends. CpG-ODN (Invivogen, USA), Potassium lactate, EGTA, Cyclosporin A (Sigma-Aldrich, St. Louis, MO, USA), Gallein, 8-Bromo cAMP sodium salt, AR-C155858 (Tocris Biosciences, Bristol, UK), and CAMKII Inhibitor (Calbiochem, USA) were used for treating pDCs as indicated.

Experiments were carried out with Milli-Q water (18.2 MΩ·cm). Inorganic salts, hydrogen peroxide (30% solution), potassium lactate (60% solution), (3-aminopropyl)triethoxysilane (APTES) (99%), (3-aminopropyl)trimethoxysilane (APTMS) (97%), trimethoxy[3-(methylamino)propyl]silane (MAPS) (95%), vinyltrimethoxysilane (VTMS) (97%), triethoxyvinylsilane (VTES) (97%), triethoxymethylsilane (MTES) (99%), triethoxy(ethyl)silane (ETES) (96%), and organic solvents were obtained from Sigma-Aldrich (Burlington, MA, USA) or Reachim (Moscow, Russia) at the highest purity and used as received.
Lactate oxidase (LOx, EC1.1.3.2) from Pediococcus species (Sorachim, Lausanne, Switzerland) was used in the form of a lyophilized protein with a declared activity of 32.8 U/mg. Standardized human serum samples were obtained from Spinreact (Girona, Spain).
Planar three-electrode hydrogen peroxide sensors (i.e., a Prussian-blue-modified carbon working electrode, a carbon counter electrode, and a Ag/AgCl reference electrode) were purchased from Rusens LTD (Moscow, Russia). Sensor performance characteristics in batch-regime mode showed a sensitivity of 0.7 ± 0.1 A·M⁻¹·cm⁻² and a lower detection limit of 5 × 10⁻⁷ M.