Bovine serum albumin (bsa)

Cells were fixed with 4% paraformaldehyde in phosphate-buffered saline (Paneco, Moscow, Russia) for 10 min at room temperature and permeabilized with 0.1% Triton X-100 for 10 min. Non-specific binding was blocked with 10% normal goat serum (Abcam, Cambridge, UK) in 1% bovine serum albumin (Paneco, Moscow, Russia), and cells were stained with antibodies to alpha-actin (ab32575; Abcam; dilution 1/100), Alexa 594-phalloidin (A12381; Molecular probes, Eugene, OR, USA), or non-specific rabbit IgG (NSC-2025; Santa Cruz Biotechnology, Dallas, TX, USA) overnight at 4 °C. Staining with secondary antibodies conjugated to Alexa 488 or 594 (#A11034, #A21203, Invitrogen Waltham, MA, USA) was performed at room temperature in the dark for 1 h. The nuclei were stained with DAPI (D9542, Sigma-Aldrich, St. Louis, MO, USA). Images from at least 4 representative fields of view per well were obtained using an inverted microscope with a fluorescent module, Leica DMi8, and Leica DFC7000 T cameras (Leica Microsystems GmbH, Wetzlar, Germany), followed by processing with LasX (Leica Microsystems GmbH, Wetzlar, Germany) and FIJI (GitHub Inc., San Francisco, CA, USA).

IR-780 iodide (Sigma-Aldrich, Saint Louis, MO, USA), Nile Blue A perchlorate (Sigma-Aldrich, Saint Louis, MO, USA), Poly(D,L-lactide-co-glycolide) (RG 858 S, Poly(D,L-lactide-co-glycolide) ester terminated, lactide:glycolide 85:15, Mw 190,000–240,000 Da, Sigma, Darmstadt, Germany), PVA (Mowiol 4-88, Sigma, Steinheim, Germany), chitosan oligosaccharide lactate (5 kDa, Sigma, Steinheim, Germany), penicillin/streptomycin (Paneco, Moscow, Russia), 2 mM L-glutamine (Paneco, Moscow, Russia), DMEM/F12 with 2 mM L-alanyl-L-glutamine (Gibco, Paisley, UK), Hoechst33342 (Thermo Fisher Scientific, Waltham, MA, USA), Versene solution (Paneco, Moscow, Russia), penicillin-streptomycin (Paneco, Moscow, Russia), bovine serum albumin (Paneco, Moscow, Russia), Herceptin (Roche, Mannheim, Germany), Crystal violet dye (LenReaktiv, St. Petersburg, Russia), fetal bovine serum (HyClone, Logan, UT, USA), Carboxy-H₂DCFDA, (Thermo Fisher Scientific, Waltham, MA, USA), and resazurin sodium salt (AlfaAesar, Lancashire, UK).

To block nonspecific binding sites, cells were incubated with a 10% solution of normal goat serum (Sigma, St. Louis, MI, USA) in PBS with the 1% bovine serum albumin BSA (PanEco) for 1 h at RT. Then, the samples were incubated with a solution of anti-CD206 antibodies (ab64693, Abcam, 1:100) or rabbit polyclonal control IgG (910801, Biolegend) as a control for 2 h at RT, and subsequently with Goat anti-Rabbit antibody conjugated with Alexa594 (A11037, Invitrogen, 1:1000). The nuclei were labeled with DAPI (Sigma, St. Louis, MI, USA). Samples were analyzed with a Leica DM6000B fluorescent microscope equipped with a Leica DFC 360FX camera (Leica Microsystems GmbH, Wetzlar, Germany).