Bioglass and bio-microlenses: synthetic biology’s leap into optics

Synthetic biology continues to blur the lines between natural and man-made materials. Recently we have heard how living organisms have been harnessed to offer alternatives to textiles, and traditional plastics, however the capabilities of micro-organisms do not stop there. Researchers are increasingly turning to living organisms to provide innovation in a range of unlikely industries. One exciting development has recently come about in an area which straddles the fields of synthetic biology and optics; “bioglass”

Engineering bacteria to build bioglass

Recently, a research team led by the University of Rochester have used the principles of synthetic biology to create living optical devices. It had previously been shown that Escherichia coli (E. coli) can be engineered to express silicatein, an enzyme from sea demosponges that catalyses the condensation of soluble silicates into inorganic polysilica (“bioglass”). Remarkably, engineering E. coli for the silicatein-catalyzed production of bioglass only requires the introduction of a single enzyme - silicatein itself.

In their recent research, the team from the University of Rochester fused silicatein to the E. coli outer membrane protein OmpA, which directed silicatein to the surface of the bacterial cells. Once in position, the functionality of the introduced protein was tested by incubating the cells with orthosilicate (a silicate precursor). Sure enough, the cells began to mineralise a bioglass shell.

Microbial optics in action

The researchers then showed that the bioglass-encapsulated bacteria could focus light into intense nanojets; a behaviour akin to that of microscopic optical devices.

These bacteria are one of the first examples of engineered biological microlenses, serving as a proof-of-concept that synthetic biology can be harnessed to create tuneable photonic components.

Looking forward, researchers in the space are focused on establishing how the synthetic systems can be fine-tuned to adjust the optical properties of the “bio-microlenses”. They predict that manipulating the size and length of bacteria would alter micro-lens properties for example, or that a specific stimuli-responsive element could be introduced to the silicatein gene to co-ordinate lens formation with changes in the cellular environment.

A greener future for photonics

With the knowledge that known cell-based bio-microlenses are similar in size and shape to photonic structures used for subwavelength microscopy and the formation of photonic nanojets, there is optimism that fine-tuned bacterial microlenses will find a variety of uses including in advanced biosensing, super-resolution imaging and photovoltaics (converting light into electricity). Better yet, unlike traditional lenses, these bio-lenses avoid the use of toxic chemicals typically used in the manufacturing process, providing a more environmentally friendly alternative.

This pioneering work highlights the exciting potential of synthetic biology to bridge the gap between living systems and materials science. By repurposing microorganisms to fabricate functional photonic components, researchers are opening new pathways toward sustainable and programmable optical technologies. Although further development is necessary before this discovery can be transformed into a commercially viable invention, it serves as clear demonstration of the versatility of microorganisms as micro-factories capable of producing unexpected and valuable products.

This piece was co-authored by Amelia Jones and Calum Graham.