Silicon nanoparticles for oral administration of molecular hydrogen

Abstract

Medical use of hydrogen gas (H2) has been given increasing attention over the past 15 years with numerous clinical trials for a variety of indications. The biological activity of H2 includes antioxidant properties and thereby the ability to neutralize damaging reactive oxygen species (ROS). Administration of hydrogen as a medical gas is limited by the poor water solubility and by the flammability of H2 in air. Therefore, nanocarriers have been investigated for safer and more efficient administration of hydrogen. Silicon particles are suggested for oral administration with the ability to undergo a redox reaction with water to produce H2 in vivo. The purpose of this work was to investigate the hydrogen generating abilities of silicon particles synthesized by centrifugal chemical vapor deposition (cCVD). High hydrogen generation rates up to 1310 ml/g at physiological pH 7.4 (82 % yield) were observed. An in vitro model of oral administration showed that pretreatment in artificial gastric juice did not affect hydrogen generation. Thus, the cCVD silicon particles seem to be suitable for in vivo hydrogen generation. A surface carbon coating or addition of surfactants or albumin hindered hydrogen generation. The addition of egg white reduced hydrogen generation but did not block it.

Study details

Article type

Original Research

Disease / injury model

None. The purpose of this work was to investigate the hydrogen generating abilities of silicon particles synthesized by centrifugal chemical vapor deposition (cCVD).

Outcome

Positive

Findings

Silicon particles made by the cCVD process were effective hydrogen gas generators at physiological pH conditions. The yield of produced H2was 97 % at pH 8 and 82 % at pH 7.4. A carbon coating on the surface of the particles hindered hydrogen generation. The addition of surfactants and proteins caused a reduction of produced H2, and pre-treatment in artificial stomach juice did not reduce the particles’ ability to produce H2 at pH conditions similar to the intestines.