A portable fluorescence reader device. Researchers at the Indian Institute of Science (IISc.) and Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) have developed a paper-based platform which could help quickly detect the presence of antibiotic-resistant, disease-causing bacteria.
| Photo Credit: Special Arrangement

Researchers at the Indian Institute of Science (IISc.) and Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) have developed a paper-based platform which could help quickly detect the presence of antibiotic-resistant, disease-causing bacteria.

According to the World Health Organisation (WHO), a handful of such bacteria, including E. coli and Staphylococcus aureus, have caused over a million deaths, and these numbers are projected to rise in the coming years. Hence, timely diagnosis can improve the efficiency of treatment.

“Generally, the doctor diagnoses the patient and gives them medicines. The patient then takes it for two to three days before realising that the medicine is not working, and goes back to the doctor. Even diagnosing that the bacteria is antibiotic-resistant from blood or urine tests takes time. We wanted to reduce that time-to-diagnosis,” said Uday Maitra, Professor in the Department of Organic Chemistry, IISc.

In a paper published in ACS Sensors, Prof. Maitra’s lab and collaborators have addressed this challenge. They have developed a rapid diagnosis protocol that uses a luminescent paper-based platform to detect the presence of antibiotic-resistant bacteria.

There are different ways by which a bacterium becomes resistant to antibiotics.

In one, the bacterium evolves, and can recognise and eject the medicine out of its cell. In another, the bacterium produces an enzyme called β-lactamase, which hydrolyses the β-lactam ring – a key structural component of common antibiotics like penicillin and carbapenem – rendering the medication ineffective.

The approach developed by the IISc and JNCASR team involves incorporating biphenyl-4-carboxylic acid (BCA) within a supramolecular hydrogel matrix containing terbium cholate (TbCh). When scrutinised by UV light, this hydrogel emits green fluorescence.

The team also collaborated with Adiuvo Diagnostics, a Tamil Nadu-based company, to design a customised, portable and miniature imaging device, named Illuminate Fluorescence Reader.

Infusing the hydrogel in a sheet of paper as the medium reduced the cost significantly. The instrument is fitted with different LEDs that shine UV radiation, as required. Green fluorescence from the enzyme is captured by a built-in camera. A dedicated software app measures the intensity, which can help quantify the bacterial load.

The team from IISc tied up with Jayanta Haldar’s research group from JNCASR to check their approach on urine samples.

As the next step, the researchers plan to tie up with hospitals to test this technology with samples from patients.

The Indian Institute of Science, Bengaluru

An interdisciplinary team of researchers from the Indian Institute of Science have uncovered how the stiffness of a cell’s microenvironment influences its form and function. The findings are expected to provide a better understanding of what happens to tissues during healing of wounds.

Scar formation

“Inefficient wound healing results in tissue fibrosis, a process that can cause scar formation and may even lead to conditions like cardiac arrest. Changes in the mechanical properties of tissues like stiffness also happen in diseases like cancer,” IISc said.

The research team was led by Prof. Namrata Gundiah from the Department of Mechanical Engineering and Prof. Paturu Kondaiah from the Department of Developmental Biology and Genetics.

Change in stiffness

In the study, published in Bioengineering, the team cultured fibroblast cells, the building blocks of our body’s connective tissue, on a polymer substrate called PDMS with varying degrees of stiffness.

They found that a change in the stiffness altered the cell structure and function. Fibroblast cells are involved in extensive remodelling of the extracellular matrix (ECM) surrounding biological cells.

The ECM, in turn, provides the mechanical tension that cells feel inside the body. The team found that fibroblasts cultured on substrates that had lower stiffness were rounder and showed accompanying changes in the levels of cytoskeleton proteins such as actin and tubulin. Moreover, fibroblasts grown on such substrates showed cell cycle arrest, lower rates of cell growth and cell death.

Regulator that drives changes

To pinpoint the master regulator that drives changes in the cell when substrate stiffness changes, the team focused their attention on an important signalling protein called Transforming Growth Factor-β (TGF-β). Previous work has shown that the activity of fibroblasts and the downstream ECM architecture is regulated by TGF-β.

“The thing is, people talk about the chemical changes but not about biomechanical changes. For example, while the TGF-β signalling cascade has been studied extensively in cancer, the influence of mechanical forces such as substrate stiffness has not been studied so far,” said Brijesh Kumar Verma, first author of the study. In the future, the researchers seek to understand how other mechanical factors, such as surface properties and cell stretch, can also influence TGF-β activity.