Developing Novel Fabrication and Optimisation Strategies on Aggregation-Induced Emission Nanoprobe/Polyvinyl Alcohol Hydrogels for Bio-Applications.

Javad Tavakoli,Jesus Shrestha,Maryam A Rad,Colin L Raston,Joanne L Tipper,Youhong Tang,Majid E Warkiani,Sajad R Bazaz

doi:10.3390/molecules27031002

Javad Tavakoli, Jesus Shrestha + Show 6 more

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https://doi.org/10.3390/molecules27031002

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Abstract

The current study describes a new technology, effective for readily preparing a fluorescent (FL) nanoprobe-based on hyperbranched polymer (HB) and aggregation-induced emission (AIE) fluorogen with high brightness to ultimately develop FL hydrogels. We prepared the AIE nanoprobe using a microfluidic platform to mix hyperbranched polymers (HB, generations 2, 3, and 4) with AIE (TPE-2BA) under shear stress and different rotation speeds (0–5 K RPM) and explored the FL properties of the AIE nanoprobe. Our results reveal that the use of HB generation 4 exhibits 30-times higher FL intensity compared to the AIE alone and is significantly brighter and more stable compared to those that are prepared using HB generations 3 and 2. In contrast to traditional methods, which are expensive and time-consuming and involve polymerization and post-functionalization to develop FL hyperbranched molecules, our proposed method offers a one-step method to prepare an AIE-HB nanoprobe with excellent FL characteristics. We employed the nanoprobe to fabricate fluorescent injectable bioadhesive gel and a hydrogel microchip based on polyvinyl alcohol (PVA). The addition of borax (50 mM) to the PVA + AIE nanoprobe results in the development of an injectable bioadhesive fluorescent gel with the ability to control AIEgen release for 300 min. When borax concentration increases two times (100 mM), the adhesion stress is more than two times bigger (7.1 mN/mm2) compared to that of gel alone (3.4 mN/mm2). Excellent dimensional stability and cell viability of the fluorescent microchip, along with its enhanced mechanical properties, proposes its potential applications in mechanobiology and understanding the impact of microstructure in cell studies.

Highlights

Hydrogels are three-dimensional cross-linked networks with the ability to uptake large amounts of water, i.e., up to 1000 times, of their dry weight [1]
We found that the associated maximum fluorescence intensity increased approximately 3-fold and 12-fold, respectively, for hyperbranched polymer (HB) generations 2 and 3 compared to the aggregation-induced emission (AIE) alone
This finding suggested that the injectable bioadhesive gel can potentially be used as a carrier for aggregation-induced emission fluorogens (AIEgens) delivery

Summary

Introduction

Hydrogels are three-dimensional cross-linked networks with the ability to uptake large amounts of water, i.e., up to 1000 times, of their dry weight [1]. Thermo-responsive and pH-sensitive hydrogels have been employed for targeted delivery and sustained release of biological compounds [5,6,7]. These hydrogels generally require different environmental stimulators, such as magnetic and electric fields [8,9], biomolecule concentration [10,11], and temperature [12,13] to control their swelling properties. Extensive efforts have been put to prepare unique hydrogels with improved physical, mechanical, and biomedical properties for a wide range of applications [14,15,16]

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