RESUMO
Nanogels play a leading role in controlled release systems because they possess high water retention capacity resulting in high loading capabilities, stability in biological fluids and biocompatibility. In this scenario, every tool that allows extending the nanogel properties and expanding their potential applications is of high interest in the field of biomedicine. This article aims to contribute to the development of multifunctional nanogels, based on the combination of two polymer phases in a multilobular morphology. The synthesized multilobed nanogels (mLNGs) presented a core of crosslinked poly(N-vinylcaprolactam) (PVCL) and a shell formed by 3-D distributed lobes of a low Tg copolymer. This particular multilobular morphology is able to exploit the synergetic contribution of both phases. While the PVCL-based core conferred its characteristic thermal response and the ability to load and release a cargo molecule, the low Tg lobes incorporated the capability of film formation. Moreover, the multilobular arrangement of NGs allows films to undergo unrestricted mass transfer. The development of mLNG morphology and the effect of synthesis parameters were deeply studied with the help of a previously developed mathematical model for the dynamic evolution of particle morphology. Finally, this study presents, for the first time, the synthesis of two-phase nanogels with multilobular morphology and underlines their potential as a candidate for controlled delivery platforms.
RESUMO
The chemical coupling of a protoplasmatic antigen from Mycobacterium avium subsp. paratubeculosis onto core-shell carboxylated particles was investigated with the aim of producing latex-protein complexes to be used in immunoagglutination assays capable of detecting bovine paratuberculosis disease. For this purpose, sensitizations were carried out using both colored and not colored carboxylated latexes as well as the protoplasmatic antigen at pH close to its isoelectric point to favor the antigenic protein to approach the particle surface. In all cases, higher fractions of proteins were chemically-bound to carboxyl groups on the surface of the particles. The assessment of the performance of the visual immunoagglutination assays consisted of evaluating 111 sera from healthy and infected bovines with Mycobacterium avium subsp. paratuberculosis. Complexes obtained from the colored latex allowed an acceptable visual discrimination between the studied positive and negative sera. Most of the positive samples showed strong to very strong agglutination and only a few samples reacted weakly, i.e. a sensitivity of 70%. The specificity of the assay, on the other hand, was 86%. Therefore, this rapid detection technique allows an easy and inexpensive identification of animals possibly infected with paratuberculosis "in situ" in the herds.
