Water immobilization by glass microspheres affects biological activity

Area of Science:

• Materials Science
• Biophysics
• Toxicology

Background:

• Myofibrillar protein hydrogels show increased water holding capacity with microparticle addition.
• Glass microspheres were previously observed to decrease water proton spin-spin relaxation time (T2) in gels, suggesting enhanced water binding.

Purpose of the Study:

• To investigate if water proton relaxation changes are a direct result of water-glass interactions.
• To understand the effects of glass microspheres on pure water properties and biological systems.

Main Methods:

• Measurement of T2 relaxation times of water protons.
• Assessment of water molecule self-diffusion coefficients.
• Determination of water activity and O-H bond strength.
• In vitro cell growth assays (human embryonic kidney, leukemia, monocytic lymphoma).
• Biological assays for seed germination and bacterial growth (alfalfa, E.coli).

Main Results:

• Glass microspheres significantly reduce water proton T2, decrease water molecule self-diffusion, lower water activity, and strengthen O-H bonds.
• Glass microspheres inhibited the growth of human embryonic kidney cells, alfalfa seeds, and E.coli.
• Dose- and time-dependent stimulation or inhibition of leukemia and monocytic lymphoma cell growth was observed.

Conclusions:

• Glass microspheres directly alter the physical and chemical properties of pure water, indicating significant water-glass interactions.
• Even inert materials like glass can exhibit biological effects when reduced to microparticle sizes.
• Microparticle size influences material behavior, with implications for toxicology and potential applications in modulating hydration for cellular/organism function.