Poly ethylene glycol diacrylate

Chitosan (low molecular weight 50,000–190,000 Da; deacetylation degree 75–85%), diacrylate poly(ethylene glycol) (crosslinker, Mn = 700 g/mol), 2-hydroxy-2-methylpropiophenone (photoinitiator, d = 1.077 g/mol, 97%, Mw = 164.2 g/mol) and L-aspartic acid (≥98%) were purchased in Merck (Darmstadt, Germany). Starch (natural potato-Starch) was bought in Avantor Performance Materials Poland S.A. (Gliwice, Poland). All reagents were applied without further purification.

Potassium hydroxide (pure, p.a.) and corn starch (pure, p.a.) were bought from Avantor Performance Materials, Gliwice, Poland, S.A. Acrylic acid (99%; p.a., anhydrous, contains 200 ppm MEHQ as inhibitor), diacrylate poly(ethylene glycol) (crosslinking agent; average molecular weight Mn = 575 g/mol; density = 1.12 g/mL), 2-hydroxy-2-methylpropiophenone (photoinitiator, density: 1.077 g/mL) and phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide were received from Merck (Darmstadt, Germany). Matricaria chamomilla L. leaves were purchased in Herbapol (Lublin, Poland).

Chitosan (high molecular weight, deacetylation degree 75–85%), gelatin (obtained from porcine skin, Type A, gel strength 300), 2-hydroxy-2-methylpropiophenone (photoinitiator, d = 1.077 g/mL, 97%), diacrylate poly(ethylene glycol (crosslinking agent, d = 1.120 g/mL, average molecular weight Mn = 700 g/mol), and polyvinylpyrrolidone (average molecular weight 10,000 g/mol) were bought in Merck (Darmstadt, Germany). Silver nitrate (99.9%, pure p.a.) and sodium borohydride (NaBH₄, 98%, pure p.a.) were purchased from Avantor Performance Materials Poland S.A. (Gliwice, Poland). Glycyrrhiza glabra (Licorice) root was bought in Natur-Sklep (Wrocław, Poland).

Polyvinylpyrrolidone (PVP, average molecular weight 10,000 g/mol), L-ascorbic acid (vitamin C, ≥99%, ACS reagent), diacrylate poly(ethylene glycol) (PEGDA 575—average molecular weight 575 g/mol and PEGDA 700—average molecular weight 700 g/mol), and 2-hydroxy-2-methylpropiophenone (97%) were bought in Sigma Aldrich (Saint Louis, MO, USA). In turn, Aloe vera juice (100%) was purchased from Herbal Pharmaceuticals (Krakow, Poland). All reagents were applied as received without further purification.

Aloe vera juice acting as an active substance and introduced into the hydrogel matrix was purchased from Herbal Pharmaceuticals (Krakow, Poland). All other reagents, i.e., vitamin C (an active substance, L-ascorbic acid, an ACS reagent; ≥99%), polyvinylpyrrolidone (the basic component of the polymer network, PVP; average molecular weight: 58,000 g/mol), diacrylate poly(ethylene glycol) (used as a crosslinker, PEGDA; average molecular weight: 575 g/mol and 700 g/mol), and 2-hydroxy-2-methylpropiophenone (Darocur^® 1173, 97%; used to initiate the photopolymerization process), were purchased from Sigma Aldrich (Saint Louis, MO, USA). All reagents were used without further purification.

Chitosan (high molecular weight; deacetylation degree 75–85%), diacrylate poly(ethylene glycol) (PEGDA; crosslinking agent; average molecular weight M_n = 700 g/mol), and 2-hydroxy-2-methylpropiophenone (photoinitiator; 97%; d = 1.077 g/mL) were purchased from Sigma Aldrich (Saint Louis, MO, USA). Aloe vera juice (99.5%) was purchased from Herbal Pharmaceuticals (Kraków, Poland). Albumin (from chicken egg whites, lyophilized powder) and hydrochloric acid (35–38%; d = 1.19 g/mL) were purchased from Avantor Performance Materials Poland S.A. (Gliwice, Poland). Next, potassium phosphate, phosphate buffered saline (PBS, tablets) and tris(hydroxymethyl)aminomethane (≥99.8%, ACS reagent) were purchased from Merck (Darmstadt, Germany). Acetate buffer solution (pH = 5.5) was purchased from Pol-Aura (Zabrze, Poland).

Polyvinylpyrrolidone (PVP, average molecular weight 58,000, powder), 2-hydroxy-2-methylpropiophenone (photoinitiator, d = 1.077 g/mL, 97%), diacrylate poly(ethylene glycol) (crosslinking agent, average molecular weight M_n = 700 g/mol, PEGDA) and L-Ascorbic acid (vitamin C, ACS reagent, ≥99%) were bought in Sigma Aldrich (Saint Louis, MO, USA). Aloe vera juice was purchased from Herbal Pharmaceuticals (Kraków, Poland).