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Log Reduction Measurements of Soft Solids (Chitosan and Polyacrylic Acid Gel Particles) in Solution

posted on 2024-06-28, 07:04 authored by Balasubramanian Vasanthakumar, Brij M. Moudgil
The provided CSV file, titled "Log reduction of E.coli in SOLUTION," serves as a repository for the raw data utilized in generating the plots depicting the reduction of E. coli cells across three experimental trials. These trials investigated the efficacy of chitosan, polyacrylic acid, and soft solids in reducing E. coli populations within a solution environment. Notably, these experiments were conducted without the presence of an artificial skin substrate.
The enumeration of bacterial populations was conducted employing the agar plate count method facilitated by serial dilution techniques. Bacterial removal was expressed logarithmically as log10 bacterial removal, as defined by Eqn. (1):

log10 bacterial removal = log10 (Initial bacterial inoculum on skin) − log10 (bacteria remaining on skin) (1)

The results were presented in terms of the total number of bacteria reduced, measured in colony-forming units (CFU), on a logarithmic scale.

Moreover, the CSV file provides data on the average log reduction of E. coli cells, along with the corresponding standard deviations, for each sample comprising either individual polyelectrolytes or polyelectrolyte mixtures (soft solids). Specifically, Columns B and D contain data pertaining to the average log reduction of E. coli cells in the presence of individual polyelectrolytes, with Column H serving as the standard X-axis reference. Conversely, Column F presents the average log reduction of E. coli cells in the presence of polyelectrolyte mixtures (soft solids), aligned with Column I as the shared X-axis.

In addition, CSV files 1–3 represent separate data obtained from Chitosan–Solution, PAA–Solution, and Complex–Solution experiments, respectively. 

Measurement condition

The cell viability in the suspension was determined via the agar plate count (serial dilution) method after incubating at 37°C overnight before counting colony-forming units (CFU). Following this incubation period, colony-forming units (CFU) were enumerated to gauge the extent of bacterial removal. The results were then articulated in logarithmic scale, indicating the total count of bacteria eradicated, as per the equation provided earlier.

Experimental condition
Bacterial suspension 106 CFU/ml was directly added to the suspensions of the desired suspensions of desired polyelectrolytes/polyelectrolyte mixtures, vortexed for 30 s at 1500 rpm (37×g) and neutralized with D/E broth. The centrifugation speed (1500 rpm (37×g)) chosen for this experiment was verified not to affect concentrations of free bacteria in the suspension.


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