SERS-Based Immunoassays for the Detection of Botulinum Toxins A and B Using Magnetic Beads

Round 1

Reviewer 1 Report

Sensors-599606

 

The manuscript entitle “SERS-based Immunoassays for the Detection of Botulinum Toxins A and B Using Magnetic Beads” proposed by Kim et al. describe a very interesting method for the detection of harmful diseases using SERS. The methodology is not new due to the few reports of the same group on the use of such method for the detection of biomarkers for cancer and strokes earlier detection and hormones. In general, the manuscript fits very well into the field covered by the journal Sensors. However, few comments might help to address  some open questions, see below. Consequently, I recommend publication in Sensors after major revision.  

Comments:

Magnetic beads are composed of what? Iron oxide? This description is very important. The magnetic particles should be characterized by TEM, DLS UV-Vis and their magnetic properties (superparamagnetic? ferromagneticas?). Or at least, the authors should report their work where the readers can see these characterizations.

This is very important to understand the effect of the magnetic behaviour/size of the particles on the uptake and SERS detection of the harmful compound.

For a better understanding of the method, the UV-Vis and Raman spectra of the dyes (Nile blue A and MGITC) should be demonstrated together with the Au NPs with the Raman reports before the detection of the BoNT/A and BoNT/B antibodies. What happen before? There are differences?

The readers must be able to see why the authors used a Raman reporter to detect the BoNT/A and BoNT/B and the main differences in the Raman spectra before and after the detection of the BoNT/A and BoNT/B antibodies.

What is the purpose for the addition of TMB? This should be more specific.

Page 5, line 195 “The absorbance at 450 nm was measured to quantify the target BoNT toxins.”

It is 450 or 405nm? In the S2b caption is described that the UV-Vis measurements were performed at 405 nm but in the text is at 450nm? What value is the correct one?

Did the authors detect interference on the Raman signal due to the presence of the magnetic beads?

Figure 4: the numbers on the left of each graph must be bigger.

Page 7, line 227, “The error bars indicate standard deviations from three measurements.” The authors mean different samples in different days? Different Au NPs batch? Different magnetic beads? Same sample, 3 replicas? What about reproducibility?

Author Response

Please see the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors presented BoNT detection by using plasmonic Au nanoparticle and magnetic bead system with antibody strategy. The study was well performed and manuscript was also well-written.

I have few questions and minor issue on the submitted manuscript as below:

 

The authors performed Raman reporter labeling by simple mixing with as-prepared citrate-stabilized AuNPs. What is the major driving force to surface loading of Raman reporters such as isotherm adsorption or electrostatic interaction, and so on? AuNPs surface conjugation of PEG-thiol did not affect to the previously loaded Raman reporters? Dislocation or releasing might be happened. In Figure 4a and 4b, BoNT/B concentration notifications were too small to distinguish in printed paper.

Author Response

Please see the attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript can be accept in it present form