Tóm tắt

The aim of this paper is to present and characterize Polyamidoamine-based hydrogels (PAA) as scaffolds to hostrnphotoactive Chlorophylla(Chl a) from Spirulina (Arthrospira platensis) sea-weed Extract (SE), for potentialrnapplications in Photodynamic Therapy (PDT). The pigment extracted from SE was blended inside PAA withoutrnfurther purification, according to Green Chemistry principles. A comprehensive investigation of this hybridrnplatform, PAA/SE-based, was thus performed in our laboratory and, by means of Visible absorption and emissionrnspectroscopies, the Chl a features, stability and photoactivity were studied. The obtained results evidenced thernpresence of two main Chl a forms, monomeric and dimeric, interacting with hydrogel polyamidoamines net-work. To better understand the nature of this interaction, the spectroscopic investigation of this system wasrnperformed both before and after the solidification of the hydrogel, that occurred at least in 24 h. Then, focusingrnthe attention on solid scaffold, thern1rnChl arn⁎rnfluorescence lifetime and FTIR-ATR analyses of PAA/SE were carriedrnout, confirming the findings. The swelling and Point Zero Charge (PZC) measurements of solid PAA and PAA/SErnwere additionally performed to investigate the hydrogel behavior in water. Chl a molecules blended in PAA werern(photo) stable and photoactive, and this latter feature was demonstrated showing that the pigment induced,rnwhen swelled in water and under irradiation, the formation of singlet oxygen (rn1rnO2), measured by direct andrnindirect methods.