T-Shaped Microfluidic Junction Processing of Porous Alginate-Based Films and Their Characteristics.

Muhammad Farhan,Israfil Kucuk,Betul Mutlu

doi:10.3390/polym11091386

Abstract

In this work, highly monodisperse porous alginate films from bubble bursting were formed on a glass substrate at ambient temperature, by a T-shaped microfluidic junction device method using polyethylene glycol (PEG) stearate and phospholipid as precursors in some cases. Various polymer solution concentrations and feeding liquid flow rates were applied for the generation of monodisperse microbubbles, followed by the conversion of the bubbles to porous film structures on glass substrates. In order to compare the physical properties of polymeric solutions, the effects of alginate, PEG stearate (surfactant), and phospholipid concentrations on the flowability of the liquid in a T-shaped microfluidic junction device were studied. To tailor microbubble diameter and size distribution, a method for controlling the thinning process of the bubbles’ shell was also explored. In order to control pore size, shape, and surface as well as internal structure morphologies in the scalable forming of alginate polymeric films, the effect of the feeding liquid’s flow rate and concentrations of PEG-stearate and phospholipid was also studied. Digital microscopy images revealed that the as-formed alginate films at the flow rate of 100 µL·min−1 and the N2 gas pressure of 0.8 bar have highly monodisperse microbubbles with a polydispersity index (PDI) of approximately 6.5%. SEM captures also revealed that the as-formed alginate films with high PDI value have similar monodisperse porous surface and internal structure morphologies, with the exception that the as-formed alginate films with the help of phospholipids were mainly formed under our experimental environment. From the Fourier-transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) measurements, we concluded that no chemical composition changes, thermal influence, and crystal structural modifications were observed due to the T-shaped microfluidic junction device technique. The method used in this work could expand and enhance the use of alginate porous films in a wide range of bioengineering applications, especially in tissue engineering and drug delivery, such as studying release behaviors to different internal and surface morphologies.

Highlights

There are various strategies for the production of highly ordered biodegradable and biocompatible porous film structures for tissue engineering and drug delivery applications
Sun et al showed that greater polyethylene glycol (PEG)-40S proportions in the sodium alginate polymer solution caused the contact angle of the solution to decrease, which enhanced the hydrophilicity of the polymer solution [26]
Control of the microbubble thinning process was achieved by using surfactants and phospholipids, which generated alginate-based porous film structures with spherical shapes, by promoting an efficient bubble bursting process

Summary

Introduction

There are various strategies for the production of highly ordered biodegradable and biocompatible porous film structures for tissue engineering and drug delivery applications. It is of interest to produce highly monodisperse porous films having the desired porosity that brings about a suitable platform to immobilize biomolecules and cells, and to load drugs in different morphologies [1,2]. Polymeric scaffolds and film structures like alginate-based porous films have many unique advantages for tissue engineering and drug delivery systems, like biodegradable film drug carrier treatments [3]. In most porous film structures, control of the porosity of the polymeric films plays an important role in either allowing cells to be seeded within the film surfaces in larger pores or inhibiting cell infiltration in smaller pores [5]. A substantial amount of film porosity is often necessary to allow for cellular activities and interactions, including cell signaling [6]

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Conclusion