Microfluidics as a platform technology for the production of chitosan nanoparticles

The preparation of chitosan-based nanoparticles by ionotrophic gelation often leads to high batch-to-batch variability as well as in low reproducibility. A possible solution to this could be controlled mixing on a microfluidic scale. In the study presented here, chitosan tripolyphosphate nanoparticles with siRNA, mRNA and β-galactosidase as cargo will be prepared using microfluidics.

Greco A, Gabold B, Chen S, et al. Microfluidic mixing as platform technology for production of chitosan nanoparticles loaded with different macromolecules. Eur J Pharm Biopharm. 2023.

MICROFLUIDIC MIXING AS PLATFORM TECHNOLOGY FOR PRODUCTION OF CHITOSAN NANOPARTICLES LOADED WITH DIFFERENT MACROMOLECULES

Biotechnological therapeutics such as peptides, proteins, and nucleic acids often possess high specificity, efficacy, and low toxicity compared to conventional agents. However, large biomolecules with high molecular mass in particular exhibit difficulties in biodistribution and transport. In addition to difficult transport across biological barriers, targeted drug transport is also difficult. This could be facilitated by nanoparticle (NP)-based transport systems.  Due to their small size, they are able to overcome natural barriers. They also offer advantages such as increased bioavailability, protection against premature biodegradation and the possibility of targeted transport. Polymer-based nanoparticles made from naturally occurring polymers such as chitosan (CTS) are of particular interest. Chitosan has excellent biocompatibility, biodegradability and stability. In addition, it can be easily modified. CTS-NPs are often prepared via ionotrophic gelation by interaction of the positively charged chitosan a negatively charged second molecule such as tripolyphosphate (TTP). Both substances are able to trap other molecules as cargo due to cross-linking. CTS-TTP-NPs are promising because they can cross biological membranes, release active ingredients in a controlled manner, and are also produced under mild conditions.

However, ionotrophic gelation under bulk conditions leads to high batch-to-batch variability due to lack of control of the production process. In this context, microfluidic mixing could be a solution. In general, microfluidics encompasses the technology to influence flows in functional components. So-called microfluidic chips are used, which can control volumes in pL or nL in narrow channels (µm and mm range). Thus, they offer possibilities e.g. for mixing on a precise scale. In addition, microfluidic chips can be manufactured reproducibly. This makes them particularly interesting for fabricating NPs with controlled physical properties by controlling mixing speed, droplet frequency and sample volume. In addition, simplified scale-up of processes should be possible.

In the presented study, microfluidic mixing for the preparation of CTS-based NPs loaded with different macromolecules such as β-galactosidase, mRNA, and siRNA by ionotropic gelation will be investigated. The aim should be to enable a cost-effective and easily optimized production of CTS-NPs. The CTS used had a viscosity between 5-20 mPas in a 0.5% solution containing 0.5% acetic acid and a DDA of 85%. If you are looking for comparable products, do not hesitate to visit our Chitosan Online Shop or contact us by This email address is being protected from spambots. You need JavaScript enabled to view it..

RESULTS

• Successful synthesis of CTS-TPP NPs by ionotropic gelation via microfluidic mixing
• Obtained NPs with a hydrodynamic diameter of 75-105 nm, a low polydispersity of 0.15-0.22, and a positive zeta potential of 6-17 mV
• All cargos (β-galactosidase, mRNA, and siRNA) were efficiently encapsulated in the CTS-TTP NPs (EE ˃ 80%)
• Good cytocompatibility of CTS
• Increased cellular internalization of NP formulation compared to free molecules
• Successful gene silencing of siRNA encapsulated in CTS-TPP-NPs → NP are able to be taken up into the cell via endosomal escape

Conclusions: The presented study demonstrated that homogeneous and stable CTS-TPP NPs can be prepared via microfluidic mixing. All the investigated cargos were successfully encapsulated and the internalization of these into the cells was enhanced. Overall, microfluidic mixing can provide a versatile, efficient and nanoscale platform to fabricate chitosan-based nanoparticles.

Link to article: Microfluidic mixing as platform technology for production of chitosan nanoparticles loaded with different macromolecules - ScienceDirect