Dear all,
Greetings. I prepared a batch of functionalised multiwalled carbon nanotube, which I have confirmed through FTIR. I've also conducted a dispersion test in water that has remained suspended for more than 2 months (as seen in the picture attached) .
I was conducting several antimicrobial assays in the past 2 weeks and noted that my MWCNTs aggregate at the bottom after 24 h incubation at 37 °C with shaking at 200 rpm (as seen in the pic attached). I've tried preparing a working stock of 1 mg/mL of my MWCNTs as stated below:
A. In deionised water with 40 min sonication in a waterbath sonicator before diluting to the test concentration and adding the test microorganisms
B. In the respective broths (such as Mueller Hinton and Sabouraud dextrose agar) with 40 min sonication before introducing the test microorganisms
I've conducted the assays simultaneously using a commercially functionalised MWCNTs from Nanoshel but the MWCNTs aggregate at the bottom too. Has anyone encountered a similar situation and would you mind sharing how you overcame it? I would appreciate your feedback.
Thank you.
Good day!
Here what I have found for your case:
"Aggregation of SWNTs was evaluated in the presence of natural organic matter [Suwannee River humic acid (SRHA)], polysaccharide (alginate), protein [bovine serum albumin (BSA)], and cell culture medium [Luria-Bertani (LB) broth] with varying solution concentrations of monovalent (NaCl) and divalent (CaCl2) salts. Increasing salt concentration and adding divalent calcium ions induced SWNT aggregation by screening electrostatic charge and thereby suppressing electrostatic repulsion, similar to observations with aquatic colloidal particles. The presence of biomacromolecules significantly retarded the SWNT aggregation rate. BSA protein molecules were most effective in reducing the rate of aggregation followed by SRHA, LB, and alginate. The slowing of the SWNT aggregation rate in the presence of the biomacromolecules and SRHA can be attributed to steric repulsion originating from the adsorbed macromolecular layer. The remarkably enhanced SWNT stability in the presence of BSA, compared to that with the other biomacromolecules and SRHA, is ascribed to the BSA globular molecular structure that enhances steric repulsion. The results have direct implications for the fate and behavior of SWNTs in aquatic environments and biological media."
Article Influence of Biomacromolecules and Humic Acid on the Aggrega...
"It was found that MWCNTs treated with nutrient broth are well dispersed owing to the nonspecific adsorption between proteins and CNTs, and could be stable at least for one week if stored in the refrigerator at 4 °C. ... Proteins in the nutrient broth could be adsorbed onto the surfaces of CNTs spontaneously, and the hydrophilic groups of proteins may increase the dissolubility of CNTs. Moreover, the constant grinding of pristine MWCNTs and nutrient broth compounds demolishes the intact structure and augments the surface area and highly active sites (e.g., lattice defects or end caps) of MWCNTs, which increases the interaction opportunity of proteins and MWCNTs and consequently further improves the dissolubility of CNTs. ... Nonspecific adsorption between proteins and MWCNTs is indispensable for the dispersion of MWCNTs in nutrient broth".
Article Pharmacia and biological functionalities of nutrient broth d...
If you have found current answer as useful, please, do not hesitate to recommend it. That will help other researches to find the best answer, according to their purposes. Best of luck in your research!
First introduced some hydrophilic functional group onto the surface of CNT and wrapped with suitable biomacro- molecule or other suitable surfactant to avoid pai -pai interaction between CNT.
I jope it may avoid agglomeration of CNT in provided bio media.
the content of added test assay may adsorb at the CNT. It seems possible that first dispersing with added polyphosphate may avoid this.
- Badges
- Science topic
- Similar topics
- Biological Science
- Molecular Cell Biology
- Culture Cells
- Cell Line