Viewing a microcosm through a physics lens

ByLavinia E. Smith

May 1, 2022 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
Viewing a microcosm through a physics lens
Serratia marcescens biofilms developed on soft (left) and rigid (right) polyacrylamide (PAA) hydrogels. These pictures expose the summary that biofilms increase a lot quicker as substrate stiffness will increase. Credit history: Syracuse University

“What can physics supply biology?” This was how Alison Patteson, assistant professor in the University of Arts and Sciences’ physics department and also a faculty member in the BioInspired Institute, started the explanation of why her physics lab was finding out microorganisms.


In a paper released by PNAS Nexus, a new journal from Oxford Academic, she and graduate student Merrill Asp, along with the collaboration of Professor Roy Welch of the biology division, describe the astonishing findings from their modern work with bacterial colonies, that has potential to assist form even further knowing of all dwelling systems and increase results in medication and health.

Patteson and her workforce needed to look into what makes a biofilm—or a colony of microorganisms that bond together—grow and prosper on some varieties of surfaces but not some others.

In the earlier, researchers investigating this query usually grew the colonies on gels created from agar, an extract of pink algae. “It truly is a material common in culinary applications for the reason that it would make points gelatinous and adds texture,” says Patteson. “We contact it a intricate substance due to the fact it is a good but has properties like a fluid.” This combination of qualities, she points out, indicates that teasing out specifically which facets make the bacteria behave a specified way a lot more complicated. “Are they sensing the good section or the fluid element?” she asks.

As a substitute, Patteson’s group synthesized clear gel substrates that could be tuned to a certain stiffness, that would let them to get time-lapse video clips of bacterial colonies expanding on them. “We are capable to probe how much deformation the gel undergoes beneath a specific total of strain,” claims Patteson.

Viewing a microcosm through a physics lens
The remaining graphic depicts how every smaller part of the hydrogel moved primarily based on the motion of embedded fluorescent beads. To the ideal, a mathematical product of an elastic reliable is applied to determine the tension exerted by the bacteria. Credit history: Syracuse College

Tiny creatures, large surprises

“1 of the things we found is that when a biofilm grows out, it truly is essentially powerful sufficient to exert force on the substrate,” Patteson continues. “We usually think of biofilms as truly sluggish-growing items, but if they’re on some thing comfortable, they can truly disrupt it.” This has implications for disease it implies that tissue injury during and next infection might not just be brought about by reactions of the body’s immune procedure, but from the bacteria exerting strain on it.

Apart from design and manipulation of the gels, Patteson and Asp implement physics to biology in the strategies that they approach the illustrations or photos, measure the boundaries of the biofilms, and calculate how immediately the boundaries increase. “We research mechanics and comfortable issue units, so we have equations that describe how some thing deforms less than sure quantities of stress,” suggests Patteson. In contrast to with the fewer controllable agar, Patteson’s group can now make calculations to measure the forces that the biofilms are placing on the gels. In truth, by mapping the pressure, the workforce was in a position to demonstrate how biofilms exert extra tension on a rigid surface than on a softer one particular. “It helps make feeling, in a way,” says Patteson, “if you tried using to climb a sticky wall rather of a slippery wall, you could exert additional force on it. We never precisely know why in the circumstance of the biofilms, but it helps make sense that they are able to exert a lot more force and go a lot quicker.”

“Bacterial organisms, by biomass, are the most predominant daily life variety on the earth,” states Patteson, acknowledging this overlap in desire with Welch, from whose lab they procured the strains of micro organism. “We’re motivated to research them simply because they intersect with the human world,” claims Asp. “Biofilms will mature and be quite durable, at times in places that we don’t want them, regardless of whether that is in individuals with illness that are immunocompromised, or in drinking water procedure crops, or on the hulls of ships.”

Hunting ahead

It is uncomplicated to sense the team’s regard for these microscopic organisms as they speak—indeed, Patteson implies that they may keep a vital to knowledge substantially extra about organisms massive and little. “We invested 10, 20 many years sequencing the human genome, but which is not sufficient for us to have an understanding of how the entire body functions,” she says. “Just because we know the genome, we nonetheless are not able to forecast how issues will behave. This is where gentle make a difference and physics can enter in. And there are a good deal of equipment for knowing that we have just begun to utilize.”


A person of the 1st styles to seize dynamics of confined cell movement

Additional information and facts:
Merrill E Asp et al, Spreading charges of bacterial colonies rely on substrate stiffness and permeability, PNAS Nexus (2022). DOI: 10.1093/pnasnexus/pgac025
Provided by
Syracuse University


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