Agriculture and Plant Genetics
Chemistry and Nanotechnology
Green Synthesis of Biocompatible Porous Nanostructured Silica (No. T4-2201)


Nanostructured silica is a promising material with remarkable properties, such as high porosity, biocompatibility, and stability. The combination of these properties makes nanostructured silica highly applicable for catalysis, drug delivery, bioimaging, biosensing, energy storage, etc. Although these nanomaterials are being synthesized in nature by microorganisms (such as diatoms), current synthesis strategies use harsh chemical conditions, are expensive, and not environmentally friendly.

Dr. Assaf Gal and his coworkers developed a green biosynthesis of nanostructured silica that mimics a natual process using positively and negatively charged polymers as a growing substrate for the silica. This naturally inspired synthesis redundant the use of organic silicone precursors (Si(OR)4) and organic solvents in the preparation of nanostructured silica

The Need

Nanostructured silica is a group of materials composed of silica with a controllable, homogeneus, and functionalized nanosurface. The combination of a large and controllable surface area, with the stability, and biocompatibility of the silica skeleton makes nanostructured silica very useful for various applications, including catalysis, biosensing, drug delivery, paints and the food industry. However, today, their synthesis is limited by the use of organic silicone precursors, organic solvents, and harsh basic conditions. Developing a synthetic procedure for nanostructured silica synthesis in water using non-organic precursors will decrease costs and accelerate its use.

The Solution

It was discovered that polyanion-polycations phase separation could initiate the growth of silica from Si(OH)4 solution. The use of polyacrylic acid (PAA)- polyanion and polyallylamine hydrochloride (PAH)-polycation abled the silicification out of aqua solution of Si(OH)4.


Technology Essence

Silicification is a process where silicone precursor is polymerized into a dense SiO2. Usually, when Si(OH)4 is allowed to polymerize in an aqueous solution, it forms a useless low-density silica gel. The interface between the polyanion to the polycation is highly dense, so it stabilizes the silicification by the polymers’ charges and forces a dense growth. Adjustment of the polymer composition can form a variety of structures, from spheres to wires.

Figure 1- Silicification of Si(OH)4 in aqueous solution with: polyanion (blue), polycation (red) and both polyanion and poly cation (purple)

Applications and Advantages


  • Catalysis
  • Drug delivery
  • Biosensing
  • Bioimaging
  • Food industry
  • Paints



  • Green chemistry
  • Inexpensive
  • Biocompatible
  • Highly stable material
Development Status

Varied morphologies of nanostructured silica were synthesized consistently in small scale from Si(OH)4.

Market Opportunity

Nanostructured silica could be applied to various industries: foods, paints, bio, and catalysis. Enabling to synthesize these materials without the need for expansive precursors (Si(OH)4 is much cheaper than Si(OR)4), and pricey solvents (water vs. organic solvents) are estimated to reduce the production cost of these superior materials dramatically.


[1] H. Zhai, T. Bendikov, A. Gal, Angew. Chem. Int. Ed. 2022, 61, e202115930; Angew. Chem. 2022, 134, e202115930.H.

Prof Assaf Gal

Assaf Gal

Faculty of Biochemistry
Plant and Environmental Sciences
All projects (1)
Contact for more information

Dr. Vered Pardo Yissar

Director of Business Development, Exact Sciences

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