Biodegradable Microparticles for Regenerative Medicine: A State of the Art and Trends to Clinical Application

Abstract

Tissue engineering and cell therapy are very attractive in terms of potential applications but remain quite challenging regarding the clinical aspects. Amongst the different strategies proposed to facilitate their implementation in clinical practices, biodegradable microparticles have shown promising outcomes with several advantages and potentialities. This critical review aims to establish a survey of the most relevant materials and processing techniques to prepare these micro vehicles. Special attention will be paid to their main potential applications, considering the regulatory constraints and the relative easiness to implement their production at an industrial level to better evaluate their application in clinical practices.

Keywords: biomaterials; clinical application; drug delivery; emulsions; microparticles; regenerative medicine; scaffolds; tissue engineering.

Figure 1

Different strategies of microparticles usage for regenerative medicine and perspective of their clinical application. Created by BioRender.com (accessed on 25 January 2022).

Figure 2

Schematic illustration representing the main three aspects to be taken under consideration while selecting a fabrication technology for microparticles. Created by BioRender.com (accessed on 23 February 2022).

Figure 3

SEM micrographies of PLA microparticles prepared by oil-in-water emulsion process where growth factors can be loaded either as a solid dispersion in the oil, either adopting a double emulsion (W/O/W) evaporation procedure. SEM image of the microparticles was made by authors.

Figure 4

SEM micrography of degradable microparticles covered with fibroblasts L929 5 days after in vitro cell culture in DMEM medium at 37 °C. The surface of the microcarriers have been tailored to be rugous in order to promote cell adhesion. SEM image of the microparticles was made by authors.

Figure 5

Culture system for scalable growth and controlled differentiation of stem cells using surface functionalized microcarriers (MC) to promote cell attachment. MC have stimuli responsive properties which can be used to trigger cell detachment, improving thereby the cells harvesting. Created by BioRender.com (accessed on 23rd February 2022).

Figure 6

3D structures fabricated from polylactide microparticles via selective laser sintering: photo of the 3D scaffold (a), optical micrograph at higher magnification (b) and SEM image of the sintered microparticles (c) forming the 3D scaffold. Images of the 3D structures were made by authors.