Tuning Microparticle Porosity during Single Needle Electrospraying Synthesis via a Non-Solvent-Based Physicochemical Approach

Yuan Gao,Zeeshan Ahmad,Ming-Wei Chang,Yuntong Bai,Jing-Song Li,Ding Zhao

doi:10.3390/polym7121531

Yuan Gao, Zeeshan Ahmad + Show 4 more

Open Access

https://doi.org/10.3390/polym7121531

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Journal: Polymers	Publication Date: Dec 21, 2015
Citations: 57	License type: CC BY 4.0

Affiliation: Zhejiang University, De Montfort University

Abstract

Porous materials, especially microparticles (MP), are utilized in almost every field of engineering and science, ranging from healthcare materials (drug delivery to tissue engineering) to environmental engineering (biosensing to catalysis). Here, we utilize the single needle electrospraying technique (as opposed to complex systems currently in development) to prepare a variety of poly(ε-caprolactone) (PCL) MPs with diverse surface morphologies (variation in pore size from 220 nm to 1.35 µm) and architectural features (e.g., ellipsoidal, surface lamellar, Janus lotus seedpods and spherical). This is achieved by using an unconventional approach (exploiting physicochemical properties of a series of non-solvents as the collection media) via a single step. Sub-micron pores presented on MPs were visualized by electron microscopy (demonstrating a mean MP size range of 7–20 μm). The present approach enables modulation in morphology and size requirements for specific applications (e.g., pulmonary delivery, biological scaffolds, multi-stage drug delivery and biomaterial topography enhancement). Differences in static water contact angles were observed between smooth and porous MP-coated surfaces. This reflects the hydrophilic/hydrophobic properties of these materials.

Highlights

Porous microparticles (MPs) have well-established applications across all biomedical and physical science disciplines; ranging from drug delivery and biomaterials [1] to environmental sensing and catalysis [2,3]
The electrospraying (ES) technique is a less common method for preparing porous MP structures, with the established modulation mechanism based on the solvent evaporation rate
Previous experiments by Wu et al evidenced the validity of the ES technique for porous MP synthesis

Summary

Introduction

Porous microparticles (MPs) have well-established applications across all biomedical and physical science disciplines; ranging from drug delivery and biomaterials [1] to environmental sensing and catalysis [2,3]. The electrospraying (ES) technique is a less common method for preparing porous MP structures, with the established modulation mechanism based on the solvent (polymer vehicle) evaporation rate. This technique has several advantages over existing processes: it avoids complex synthesis procedures where the loss of material is significant; a relatively narrow particle size distribution is achievable; and ambient conditions during synthesis. We demonstrate an unconventional approach using a series of collecting non-solvents, the base solvent (DCM) for PCL solubilisation remains constant When using this approach, non-solvents’ varying physicochemical properties (e.g., surface tension, viscosity and vapour pressure) are exploited to create MPs with tailored porosity and hydrophobicity, which is devoid of multiple precursor solutions, synthesis steps and processing needles. FDA-approved biocompatible and biodegradable PCL polymer was used [16]

Materials

Preparation of Microparticles

Conclusions