Co-Encapsulation of Phycocyanin and Albumin-Bound Curcumin in Biopolymeric Hydrogels

Abstract

Co-encapsulation of hydrophilic and hydrophobic compounds within a single delivery system remains a significant challenge across various scientific and industrial fields. Towards this direction, an encapsulation strategy is proposed, enabling the simultaneous incorporation of both hydrophilic and hydrophobic biomolecules within a hydrogel matrix. Specifically, the cyanobacterial protein phycocyanin (hydrophilic), extracted and purified by dry Arthrospira maxima biomass, and curcumin (hydrophobic) bound to bovine serum albumin (BSA) were utilized. This approach facilitates the indirect entrapment of hydrophobic molecules within the hydrophilic hydrogel network. The structural and physicochemical properties of the resulting hydrogels were characterized using optical analysis, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Additionally, the antioxidant potential of the encapsulated biomolecules was evaluated to assess their functionality after the encapsulation. Furthermore, a cell viability assay confirmed the hydrogel's biocompatibility and lack of toxicity, demonstrating its suitability as a multifunctional biomaterial for biomedical and pharmaceutical applications.

Keywords: antioxidants; biopolymers; cell viability; hydrogels; morphology; structure.

Figure 1

Hydrogels after incubation at different temperatures for 1 h. From left to right: systems based on chitosan (A1, A2, A3), HPMC (B1, B2, B3) and hybrid chitosan/HPMC hydrogels (C1, C2, C3). A1–C3: refer to Table 1. L: the systems 3 d after the heating study.

Figure 2

Percent swelling ratio of empty (red) and PC-loaded (blue) hydrogel (system C1 of Table 1), as a function of the incubation time.

Figure 3

SEM images of the freeze-dried hydrogels. (A): empty hydrogel; (B): PC-loaded hydrogel; (C): CCM/BSA-loaded hydrogel; (D): CCM/BSA and PC-loaded hydrogel; (E): magnified area of the CCM/BSA-loaded hydrogel where aggregates are visible; (F): zoomed-in aggregate in CCM/BSA-loaded hydrogel.

Figure 4

(A): Confocal image ×20 magnification of the surface of hydrogel C4 loaded with phycoerythrin and (B): Confocal image ×20 magnification of a cross-section of the same system. Composition of hydrogel C4 as given in Table 1.

Figure 5

Thiazolyl blue tetrazolium bromide (MTT) cell proliferation assay with the WM164 cell line after 48 and 72 h in the presence of 10 µL crosslinked hydrogel spread at the bottom of the wells as a basis for cell growth: Dulbecco’s Modified Eagle’s Medium (DMEM); empty hydrogel, 10.4 mg (blank); hydrogel loaded with PC (PC), 10.4 mg/4 µg; hydrogel loaded with CCM/BSA (CCM), 10.4 mg/0.02 µg; hydrogel loaded with both PC and CCM/BSA (PC/CCM), 10.4 mg/4 µg/0.02 µg. The mean (±SD) of three independent experiments, each performed in five replicates, is presented. Statistically significant results are indicated by asterisks (*) when p < 0.05 and (**) when p < 0.01 (One-Way ANOVA with Bonferroni correction for multiple testing).