Sniffing Bacteria with a Carbon-Dot Artificial Nose

Abstract

Highlights Novel artificial nose based upon electrode-deposited carbon dots (C-dots). Significant selectivity and sensitivity determined by “polarity matching” between the C-dots and gas molecules. The C-dot artificial nose facilitates, for the first time, real-time, continuous monitoring of bacterial proliferation and discrimination among bacterial species, both between Gram-positive and Gram-negative bacteria and between specific strains. Machine learning algorithm furnishes excellent predictability both in the case of individual gases and for complex gas mixtures. Abstract Continuous, real-time monitoring and identification of bacteria through detection of microbially emitted volatile molecules are highly sought albeit elusive goals. We introduce an artificial nose for sensing and distinguishing vapor molecules, based upon recording the capacitance of interdigitated electrodes (IDEs) coated with carbon dots (C-dots) exhibiting different polarities. Exposure of the C-dot-IDEs to volatile molecules induced rapid capacitance changes that were intimately dependent upon the polarities of both gas molecules and the electrode-deposited C-dots. We deciphered the mechanism of capacitance transformations, specifically substitution of electrode-adsorbed water by gas molecules, with concomitant changes in capacitance related to both the polarity and dielectric constants of the vapor molecules tested. The C-dot-IDE gas sensor exhibited excellent selectivity, aided by application of machine learning algorithms. The capacitive C-dot-IDE sensor was employed to continuously monitor microbial proliferation, discriminating among bacteria through detection of distinctive “volatile compound fingerprint” for each bacterial species. The C-dot-IDE platform is robust, reusable, readily assembled from inexpensive building blocks and constitutes a versatile and powerful vehicle for gas sensing in general, bacterial monitoring in particular.

Ultra-low-temperature reversible thermochromism and contactless bacterial sensing by chalcone-functionalized polydiacetylene

“…5C further attests to the correlation between the chromatic changes of the film and bacterial proliferation, underscoring the typical exponential growth curve of bacterial populations. 48…”

“…5C further attests to the correlation between the chromatic changes of the film and bacterial proliferation, underscoring the typical exponential growth curve of bacterial populations. 48 Fig. 6 demonstrates application of the HCl-treated chalcone-PDA color sensor for visual monitoring of food spoilage.…”

The Transformation of 0-D Carbon Dots into 1-, 2- and 3-D Carbon Allotropes: A Minireview

“…More importantly, machine learning has been used to gain a further understanding and build experimental models using data and algorithms to correlate the structure–property relationship of CDs [ 139 ]. Thus, machine-learning-based techniques have been used to develop strategies that allow the synthesis of CDs with targeted optical properties [ 140 , 141 ], optimized quantum yields [ 142 ] and high selectivity in gas sensing [ 143 ]. Since machine learning is already shedding some light on the structure–property relationship, it is possible that this tool can potentially predict the identity of the CDs (i.e., GQDs, CQDs, CNDs and CPDs) and the type of dimensional carbon formed after heat treatment or catalysis reactions, and potentially can also help control the amount of dopant (e.g., N-, P-doping) in the final carbon structure.…”

Recent progress on performances and mechanisms of carbon dots for gas sensing

“…CDs and CDs‐based composites have been widely used in electrical gas sensor for the detection of ammonia (NH 3 ) gas, NO 2 , nitric oxide (NO), CO 2 , carbon monoxide (CO), hydrogen sulfide (H 2 S), and VOCs. [ 26,27,79–87 ]…”