Synthesis of hybrid nanogels by photopolymerization containing functionalized silsesquioxanes

A. GALLASTEGUI; R. A. PONZIO; C. A. CHESTA; R. E. PALACIOS; M. L. GOMEZ

Mar del Plata

Simposio; SLAP 2018 - XVI Simposio latinoamericano de Polímeros ? XIV Congreso Iberoamericano de Polímeros; 2018

INTEMA

INTRODUCTIONRecently, the development of multifunctional nanoparticles with theragnostics properties has gained increase importance1. On the other hand, Silsesquioxanes are hybrid organic-inorganic materials with a structural formula of [RSiO3/2]n; they can be synthesized from organosilanes with several functionalities and present the properties of being inert and biocompatible like silica, while organic groups facilitates the incorporation of hydrophobic molecules such as dyes and drugs2. In this work, nanogels of acrylamide and 2-hydroxyethyl methacrylate containing different silsesquioxane precursors in their structure that act as crosslinkers were synthesized. The photoinitiator system consists of a conjugated polymer, poly (9,9-dioctylfluorenoalt-benzothiadiazol) (F8BT), in the form of a nanoparticle (NP), which has the capacity to absorb and emit radiation in the visible region of the electromagnetic spectrum; and to participate as an electron transfer agent, thus initiating the polymerization by visible light without a sensitizer. In addition, NPs of F8BT are retained in the hydrogel matrix after polymerization, which represents an advantage for the application of these materials in fluorescent sensing3.EXPERIMENTAL METHODSFunctionalized silsesquioxanes (SSOF) were synthesized and characterized by FTIR, 29Si-NMR and MALDI-TOF. The obtained nanogels were characterized by DLS, Uv-visible spectroscopy, fluorescence spectroscopy, individual particle fluorescence microscopy, SEM and TEM, among others.RESULTS AND DISCUSSIONThe representative structures of the SSOFs synthesized can be observed in Figure 1. Mostly T3 with some T2 structures are obtained after hydrolysis and polycondensation reaction of SSOF precursors.AAm and HEMA nanogels were obtained employing the SSOF as crosslinkers by vible-light polymerization in a merry go round system provided with blue LEDs. The synthesized nanogels have a diameter ranging between 100-200 nm. TEM and fluorescence microscopy images of nanogels synthesized using the precursor SSOF-1 and NPs of F8BT are shown in Figure 2. As it can be seen, F8BT Nps conserve their emissive property after the photopolymerization process.CONCLUSIONHybrid nanogels of 100-200 nm diameters containing silsesquioxanes in their structures were synthesized by visible light photopolymerization.The obtained results suggest that nanogels could act as a drug release system and fluorescent detection, simultaneously, with potential application in biomedicine.