Molecularly imprinted poly(acrylonitrile‐co‐acrylic acid) matrix with sclareol

Abstract

There are presented results regarding a new set of molecularly imprinted polymers (MIPs) based on acrylonitrile:acrylic acid (AN:AA) copolymer matrix. As template, it was used sclareol, an important anticancer bioactive compound, never used before for molecular imprinting. An emerging and insufficient studied MIP preparation method, namely the phase inversion, was used to prepare 0.8 mm spherical sclareol MIPs (S‐MIPs). Three AN:AA copolymers, having the initial monomer ratios 90:10, 80:20, and 70:30, were synthesized by radical copolymerization in emulsion, without emulsifier. After that, each copolymer was dissolved in the presence of the template (sclareol) in dimethylformamide. The imprinting and the morphology of these new materials were analyzed by rheology, elemental analysis, infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, batch rebinding tests, and Scatchard analysis. The conclusion was that the AN:AA‐80:20 matrix proved to be the optimized solution between high rigidity (given by the AN segments) and high affinity for the template (given by AA segments), the average imprinting factor for this system being 2.67. POLYM. ENG. SCI., 54:1484–1494, 2014. © 2013 Society of Plastics Engineers

Thermal analyses as tools for proving the molecular imprinting with diosgenin and sclareol in acrylic copolymer matrices

“…It must be underlined that this paper is aiming for the evaluation of template presence and influence on different matrices and not the differences between matrices (AN:AA 90:10,80:20,70:30 etc. ), these differences being presented in previously published studies [2,9,[54][55][56][57][58].…”

“…In brief, phase inversion method requires the prior preparation of the (co)polymers, followed by the dissolution of template and polymer matrix in a common solvent, and finally by phase inversion or coagulation in a proper non-solvent. As described in previously published papers [2,9,54,55], the MIP synthesis consisted of four main steps: copolymerization of AN:AA matrix, template contacting in solution with the AN:AA matrix, structure stabilization in the desired shape (pearls or membranes), and template extraction. The first step is a copolymerization in emulsion without emulsifier in which the comonomer ratio was varied as AN:AA 90:10, 80:20, and 70:30, and potassium persulfate, sodium metabisulfite, and H 2 SO 4 were used as REDOX system.…”

“…The synthesis method of imprinted pearls (MIPs) is an alternative imprinting method known as wet phase inversion, which was developed and thoroughly presented in previous studies [2,9]. The main advantage of the phase inversion method is that allows the casting of MIPs in various shapes depending on mold shape, but the most encountered shapes are as membranes and beads.…”

“…Diosgenin decomposition is followed by the decomposition of acrylonitrile:acrylic acid (AN:AA) matrix, degradation that takes place for all the systems (MIP, MIP-Ex, and NIP) in two steps. The first step takes place in the interval 300-375°C and corresponds to decomposition of AA segments by dehydration of the -COOH functional groups with the formation of anhydride, which successively decomposes by decarboxylation [9,10]. The AN segments are also decomposing in this first step by dehydrogenation and suffer further stabilization by cyclization, this thermal effect overlaying with the AA one.…”

“…Among these types of analyses, an important role is represented by thermal analysis. The thermal methods most often used for MIP characterization are the thermogravimetric analysis (TG), sometimes coupled with mass spectrometry (MS) or Fourier transform infrared spectroscopy (FT-IR), the differential scanning calorimetry (DSC), pyrolysis, and dynamic mechanical thermal analysis (DMTA) [7][8][9][10][11][12][13][14][15][16][17][18][19].…”