Synthesis of hybrid nanoparticles for encapsulation and functionalization of therapeutic aptamer

Introduction:Nanomedicine is an innovative field with potential for improving many kinds of ailments.Hybrid nanoparticles (HNP), containing lipids and polymer, can protect biopharmaceuticals from biodegradation and enhance biodistribution by controlled release at therapeutic sites.Targeting and controlled delivery involves the functionalization of site-specific delivery molecules.One kind of these molecules are aptamers, single stranded oligonucleotides designed to have affinity for desired targets.Besides, the aptamer can also provide therapeutic effects.However, they alone have low plasmatic half-life.The goal of this work is to produce a nanoparticle delivery system for therapeutic aptamers by encapsulation and functionalization procedures.Prior to this work, the aptamer was synthesized based on molecular affinity to a recombinant protein and a SELEX protocol, and its biological activity was verified.Objectives: Preparing a hybrid nanoparticle containing aptamers encapsulated and functionalized. Methodology:The NP were synthesized by the nanoprecipitation method.Acetone was used as an organic solvent and 4% ethanolic solution as aqueous medium.Both polymer and lipids were dissolved in the organic phase.The mean diameter, polydispersity index (PDI) and zeta potential were evaluated by Zetasizer Ultra.Non-encapsulated aptamer was quantified by ion exchange chromatography (IEX).The aptamer activation for functionalization was carried out by a reduction procedure and purified by IEX.The functionalization took place mixing NP and tiol-activated aptamer at room temperature.The non-functionalized aptamer was analyzed by Ellman's assay.Cysteine was used as positive control for functionalization.The encapsulated aptamer was not tiol-activated. Results:The aptamer was encapsulated in HNP yielding 38,8% encapsulation efficiency, corresponding to 75 g.The diameter, PDI and zetapotential were measured as: 160,3 nm, 0,118 and + 50 mv.The functionalization capacity measured with cysteine resulted in 1,17 nmols/10 L NP.The same process was executed with aptamer and yielded 0,9 nmol /10 L NP. Conclusion:The HNP synthesis was able to encapsulate the therapeutic aptamer and the functionalization procedure yield was close to the cysteine one, used as positive control.