Cell Adsorption and Selective Desorption for Separation of Microbial Cells by Using Chitosan-Immobilized Silica

Abstract

Cell adsorption and selective desorption for separation of microbial cells were conducted by using chitosanimmobilized silica (CIS). When chitosan was immobilized onto silica surfaces with glutaraldehyde, bacterial cells adsorbed well and retained viability. Testing of the adsorption and desorption ability of CIS using various microbes such as Escherichia coli, Aeromonas hydrophila, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Lactobacillus casei, Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Saccharomyces cerevisiae, Saccharomyces ludwigii, and Schizosaccharomyces pombe revealed that most microbes could be adsorbed and selectively desorbed under different conditions. In particular, recovery was improved when L-cysteine was added. A mixture of two bacterial strains adsorbed onto CIS could also be successfully separated by use of specific solutions for each strain. Most of the desorbed cells were alive. Thus, quantitative and selective fractionation of cells is readily achievable by employing chitosan, a known antibacterial material.Infection and contagion are becoming increasing problems in our communities, for example, with nosocomial infections caused by antibiotic bacterial strains like methicillin-resistant Staphylococcus aureus, mass food poisoning caused by contaminating pathogenic bacteria like enteropathogenic Escherichia coli O157 in water or foods, and infections caused by the microscopic parasites Giardia and Cryptosporidium, which are found in water. Traditionally, these microorganisms can be found by culture-based methods, such as single-colony isolation and antibody utilization using an enzyme-linked immunosorbent assay (4,5,21). Recently, PCR has been commonly applied (9,11,12). Furthermore, various methods, such as differential staining, serological methods, flow cytometry, phage typing, protein analysis, and comparison of DNA nucleotide sequences, have been utilized. These methods enable us to detect microbes in small samples with high sensitivity (3).At the industrial level, these approaches are not suitable due to limited time and the significant effort, cost, and scale involved. The culture-based method is restricted to viable target bacteria and is time-consuming. Therefore, it is of great interest to develop novel fast and inexpensive detection, separation, and isolation methods (1,7,10).The purpose of the present study was to assess a new separation and concentration system for bacterial cells that is easy to apply and allows rapid processing by using chitosan as a functional ligand. Our final purpose in this study was to fractionate microbial cells with chitosan.

Hierarchically Porous Chitosan–PEG–Silica Biohybrid: Synthesis and Rapid Cell Adsorption

“…With increasing requirements in practical applications, incorporating biomacromolecules into silica to yield biohybrids has been regarded as a facile and versatile strategy to obtain expected functional hybrid materials together with sophisticated structures 7. Among the biomacromolecules involved in biohybrids, chitosan, a positively charged biopolymer derivative from chitin, can not only act as a structure directing agent but also provide desirable functionalities such as metal chelate capability and pH responsiveness to the obtained biohybrid 5d, 8. However, due to the redissolution of the non‐crosslinked chitosan in materials, the chitosan‐based biohybrids often lose their structural integrity when exposed to water, limiting their applications in an aqueous environment 6d…”

Comparison of inhibitory activity of bioactive molecules on the dextransucrase from Streptococcus mutans

“…This fact demonstrated that the adsorption of bacterial cells on surface and the formation of highly structured cell clusters must be associated with the ability of an organism to survive (Decker et al 2014;Kubota et al 2005), which are key factors causing a dental caries. Upon investigating using CTSNs, the inhibitory effects of other bioactive substances on DSase to elucidate biological functions that compare with the CTSNs were also performed.…”

Spatial control of cells, peptide delivery and dynamic monitoring of cellular physiology with chitosan-assisted dual color quantum dot FRET peptides

“…Chitosan was dissolved in water with 0.25 mM sodium azide (Sigma-Aldrich) and then 1.5 ml of the 0.05% chitosan solution was mixed with 0.2 ml of 25% glutaraldehyde (Sigma-Aldrich) to produce solution 1, used to create cross-links with an amino-functionalized glass slide. The entire coating process has been described schematically in Kubota et al [30]. Lint-free Kimwipes were dipped in solution 1 and then applied gently to the stamp to coat the raised surface without filling the troughs.…”

“…To form an amino-terminated layer on the surface of the substrates, we immersed them in a 3% solution of 3-(aminopropyl)-triethoxysilane (Sigma-Aldrich, St. Louis, MO) in 95% methanol with sonication for 15 min followed by thorough rinsing with methanol. They were dried for 30 min in a 120°C oven [30].…”