Elaboration of levothyroxine-selective molecularly imprinted nanostructured films

FOOKES, FEDERICO; CARLOS BUSATTO; CASIS, NATALIA; M. MARTA FIDALGO; DIANA ESTENOZ

Águas de Lindoia

Congreso; 24 Congresso Brasileiro de Engenharia e Ciência dos Materiais; 2022

Molecularly imprinted polymers (MIPs) aresynthetic polymers with predetermined selectivity toward a given analyte or agroup of structurally related species due to the creation of highly specificsites formed during the synthesis. Thyroid hormones have numerous vitalfunctions in the body as they are involved in the development of the nervoussystem and regulate various metabolic functions. Levothyroxine (T4), a thyroidhormone, is usually found in a healthy adult at levels between 100-200 ng/dL.These low concentrations determine the chemical analysis since they make itdifficult to find efficient methods for T4 detection and quantification. Hydrogelswith submicrometer pores have a specific surface that give them lowerresistance to mass transfer. Therefore, the combination of molecular imprintingtechnology with nanostructured films offers the possibility of developingplatforms for rapid detection of hormones at low concentrations. In the currentwork, nanostructured MIPs were synthesized from deposits of SiO2particles for the selective binding of T4. The colloidal deposits werefabricated by vertical lifting deposition and the MIPs were elaborated usingacrylic acid or methacrylic acid as the functional monomer. The optical propertiesof the developed materials were characterized recording their UV-visiblereflectance spectra. The swelling capacity of hydrogel films was studied atdifferent pH, their morphological and structural characterization was performedby SEM and FTIR analysis, and their T4 adsorption capacity was evaluatedthrough recognition studies. The materials showed a pH-sensitive swelling withan increasing on water absorption at higher pH values. SEM images showed filmswith high porosity. Acrylic acid films showed a higher swelling due to itslower pKa value. The reflectance peak of the silica colloidal deposits and theobtained nanostructured films was 540 and 409 nm, respectively. The recognitioncapacity obtained for the MIPs were higher than the NIPs (3.62 vs 2.02 mg/g,respectively), evidencing an efficient molecular imprinting process. Moreover,these values are similar to others reported in the literature for differenthormones. Owing to the opticalresponse and the capability of binding T4 hormone, the materials elaborated inthe current work will be applied in the development of fast response photonicsensors for the quantification of T4 in different matrices.