Potential Novel Drug Carriers for Inner Ear Treatment: Hyperbranched Polylysine and Lipid Nanocapsules

Abstract

Aim: Treatment of sensorineural hearing loss could be advanced using novel drug carriers such as hyperbranched polylysine (HBPL) or lipid nanocapsules (LNCs). This study examined HBPL and LNCs for their cellular uptake and possible toxicity in vitro and in vivo as the first step in developing novel nanosized multifunctional carriers. Method: Having incubated HBPL and LNCs with fibroblasts, nanoparticle uptake and cell viability were determined by confocal laser scanning microscopy, fluorescence measurements and neutral red staining. In vivo, electrophysiology, confocal laser scanning microscopy and cytocochleograms were performed for nanoparticle detection and also toxicity studies after intracochlear application. Results: Both nanoparticles were detectable in the fibroblasts’ cytoplasm without causing cytotoxic effects. After in vivo application they were visualized in cochlear cells, which did not lead to a change in hearing threshold or loss of hair cells. Biocompatibility and traceability were demonstrated for HBPL and LNCs. Thus, they comply with the basic requirements for drug carriers for potential application in the inner ear.

Keywords::

• acoustically evoked auditory brainstem response
• biocompatibility
• cochlear
• drug carrier
• gene delivery
• hair cells
• inner ear
• nanoparticle

Financial & competing interests disclosure

This study was supported by the European Community 6th Framework Programme on Research, Technological Development and Demonstration (Nanotechnology-based Targeted Drug Delivery. Contract number: NMP4-CT-2006–026556, Project acronym: NANOEAR). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate insti tutional review board approval or have followed the princi ples outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investi gations involving human subjects, informed consent has been obtained from the participants involved.

Additional information

Funding

This study was supported by the European Community 6th Framework Programme on Research, Technological Development and Demonstration (Nanotechnology-based Targeted Drug Delivery. Contract number: NMP4-CT-2006–026556, Project acronym: NANOEAR). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.