Page 20 - 03. Application of Ionizing Radiations - Progress Report IPEN 2014-2016

64 Application of Ionizing Radiations | Progress Report

cleotides. The radiation-induced synthesis of
PVP nanogels based on intramolecular cross-
linking has been recently established. Such ma-
terials acquire specific properties that led to a
great deal of potential applications, including
drug delivery systems, nanosensors, nanoreac-
tors, and bio-mimetic mechanical devices. In
this work, we developed poly(vinyl-1-pyrroli-
done) nanogels, synthesized by ionizing radi-
ation. Additionally, we aimed to produce PVP
albumin conjugate system for biomedical ap-
plications. On this account, PVP was irradiat-
Figure 27. Size Exclusion Chromatography (SEC) trace evolu-
tion of poly(glycidyl methacrylate) (PGMA) polymers formed in ed in gamma and electron beam sources us-
solution during grafting from cellulose surface at ambient tem- ing cosolvent system (water/acetone) at room
perature via RAFT polymerization mediated by CDB and ini-
tiated by α-radiation. (a) Mn=10,200, DM=2.97, 4.4kGy; (b) temperature. Bovine serum albumin was in-
Mn=12,700, DM=3.26, 6.4kGy;(c) Mn=35,300, DM=3.52, 8.3kGy.
corporated after nanogel formation, by resus-
composites did no present IC50, so the quan- pension of the lyophilized nanogel using satu-
tity of substances released that would cause rated protein solution. The produced systems
cell death was not significant. were characterized by means of particle size,
using dynamic light scattering. Nanostructure
Modification and preparation of polymeric images were obtained by scanning electron
nanogels by ionizing radiation microscopy. Under the evaluated conditions,

it was possible to synthetize nanostructured
Hydrophilic polymers are widely used in med- PVP hydrogels around 30-80nm hydrodynam-
icine both in soluble and insoluble (hydro- ic radius. The addition of protein to the system
gel) forms. Water-soluble polymers have been conferred distinct thermal profiles and led to
used in the clinics and/or clinical trials for the changes in the overall structure of the sys-
modification of proteins, modification of lipo- tem. Applications of the developed polymer
somes, surface modification of biomaterials, albumin conjugate involve drug delivery sys-
and as carriers of drugs, genes, and oligonu- tems with enhanced biological compatibility

Figure 28. SEM image of cellulose-g-PGMA copolymer with DG of 25% before (a) and after (b) EDA mod-
ification (Barsbay, M., et al. http://dx.doi.org/10.1016/j.radphyschem.2015.12.015i).

Instituto de Pesquisas Energéticas e Nucleares