<p>Electronic Supporting Material on the Microchimica Acta publication </p><p>Molybdenum Disulfide Quantum Dot Based Highly Sensitive Impedimetric Immunoassay for Prostate Specific Antigen</p><p>Manil Kukkar1,2#, Suman Singh1,2#, Nishant Kumar1, Satish K. Tuteja3, Ki-Hyun Kim4*, Akash Deep1,2* 1CSIR-Central Scientific Instrument Organisation (CSIR-CSIO), Chandigarh 160030, India 2Academy of Scientific and Innovative Research (AcSIR-CSIO), Chandigarh 160030, India 3BioNano Laboratory, School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada 4Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni- Ro, Seoul 04763, Korea #Equal contribution for first authorship Correspondence: [email protected], Tel.: +1-82-2-2220-2325; Fax: +82-2-2220-19451 [email protected], Tel: +91-172-2672236, Fax: +91-172-2657287</p><p>Figure S1: Schematic for the synthesis and bioconjugation of MoS2 QDs along with the development of immunoassay for PSA</p><p>1 Figure S2: 2 and 3-Dimensional AFM images of MoS2-QDs along with the line profile analysis [Features of the AFM Tip used for the scanning of samples: (a) Make- ATEC-NC-</p><p>10, (b) Radius of curvature (R) of tip ≥ 10 nm, and (c) Achievable resolution of the tip ~ 2.82 nm (calculated by standard equation of Resolution = (0.8 R)^1/2)].</p><p>Measurement parameter Bare SPCE SPCE/MoS2 QDs Contact angle (°) 73 80.05 Surface free energy (mN/m) 31.77 ±0.00 28.98 ±0.17 </p><p>Figure S3: Contact angle measurement of bare and MoS2 QD modified SPCE. An increased contact angle suggests the improved hydrophobicity of the MoS2 QD modified SPCE.</p><p>2 Figure S4: (a) Raman spectrum of MoS2-QDs and bulk MoS2, (b) XRD spectra of bulk MoS2</p><p>& MoS2-QDs, (c) EDX analysis of MoS2-QDs, and (d) FE-SEM analysis of MoS2-QDs</p><p>Figure S5: (a) UV-visible spectra of MoS2 QDs and nanosheets and (b) Fluorescence spectrum of MoS2 QDs</p><p>3 Figure S6: Current voltage response of Bare SPCE (left) and SPCE/MoS2QD modified (right).</p><p>Figure S7: Investigations on the reproducibility of the response of different SPCE/MoS2</p><p>QD/PSAAb electrodes. The EIS responses of five electrodes made in different batches were found to be overlapping with each other, thereby proving their reproducibility. </p><p>4 Figure S8: (a) Selectivity study with the SPCE/MoS2QD/PSAAb electrodes [concentrations of</p><p>PSA and other tested proteins were 0.01 and 1 pg⋅mL-1, respectively] and (b) Response of</p><p> the SPCE/MoS2QD/PSAAb electrodes with spiked PSA both in standard buffer and serum</p><p> samples </p><p>Table S1. An overview on recently reported nanomaterial-based methods for determination of PSA</p><p>S. Materials used Method Applied Linearity Limit of Specificity Ref. No. range detection</p><p>01 Nano-TiO2- Impedance spectroscopy 0.10-5.0 and Specific with [1] modified 5.0-100 respect to carbon paste 200 pg⋅mL-1 carcinoembryonic electrode antigen ng⋅mL-1 thyroid-stimulating hormone</p><p>02 Gold film Micro fluxgate device 0.1-10.0 Specific with [2] involving sandwich respect to bovine immunoassay 0.1 ng⋅mL−1 serum albumin, carcinoembryonic antigen and alpha </p><p>5 fetoprotein</p><p> ng⋅mL−1</p><p>03 Multi-walled Sandwich type 0.01-100 Specific with [3] carbon nanotubes immunosensor with respect to differential 5.4 pg⋅mL-1 carcinoembryonic pulse voltammetry ng⋅mL−1 antigen, myoglobin, mucoprotein and thrombin 04 Gold Differential 0.25-200 0.25 Specific with [4] nanoparticles pulse voltammetry respect to bovine covered with serum albumin, graphitized ng⋅mL−1 ng⋅mL−1 hemoglobin and mesoporous thrombin carbon nanoparticles 05 Functionalized Electro- 1-10 0.29 Specific with [5] graphene QDs chemiluminescence respect to carcinoembryonic pg⋅mL−1 pg⋅mL−1 antigen, bovine serum albumin glucose 06 Graphene oxide Differential pulse Specific with [6] hybridized with voltammetry respect to Human ferrocene 2 pg⋅mL−1 - 0.5 pg⋅mL−1 immunoglobin M, monocarboxylic human acid immunoglobin G, carcinoembryonic antigen, glucose −1 10 ng⋅mL and thrombin</p><p>07 Graphene sheets– Amperometry 0.05–5 Specific with [7] methylene blue– respect to alpha chitosan 13 pg⋅mL−1 fetoprotein, bovine ng⋅mL−1 serum albumin, vitamin C and glucose 08 Composite of Sandwich type Specific with [8]</p><p>Fe3O4 electrochemical respect to bovine nanoparticles immunoassay 0.1 pg⋅mL−1 0.03 pg⋅mL- serum albumin, and reduced carbohydrate graphene oxide antigen-125, 1 carcinoembryonic antigen and alpha −1 - 5 ng⋅mL fetoprotein </p><p>6 09 Reduced Differential pulse 0.1 - 80 Specific with [9] graphene oxide voltammetry respect to alpha- functionalized 53 pg⋅mL-1 fetoprotein, human with High ng⋅mL−1 immunoglobin, molecular-weight bovine serum silk peptide albumin, L- cysteine and L- Lysine</p><p>10 MoS2 QDs Impedance spectroscopy 0.01 Specific with This respect to human work 0.01 pg⋅mL−1 serum albumin, pg⋅mL−1 carcinoembryonic antigen, - 200 Immunoglobin G and alpha- fetoprotein ng⋅mL−1</p><p>7 Table S2. PSA detection in spiked serum samples and recovery study</p><p>S. No. PSA Concentration Rct (ohms) obtained Rct (ohms) Recovery (%) with standard obtained with samples spiked serum [spiked (ng⋅mL-1)] samples</p><p>01 1.0 × 10-5 5519 ± 25 5413 ± 27 102 ± 2.2 02 1.0 × 10-3 7189 ± 29 7143 ± 30 100 ± 2.6 03 1.0 × 10-1 8518 ± 35 8618 ± 39 98 ± 3.5 04 1.0 × 102 12187 ± 52 12339 ± 55 98 ± 2.5 Note that all the data reported herein are an average of triplicate analysis </p><p>References: 1. Biniaz Z, Mostafavi A, Shamspur T, Torkzadeh-Mahani M, Mohamadi M (2017) Electrochemical sandwich immunoassay for the prostate specific antigen using a polyclonal antibody conjugated to thionine and horseradish peroxidase. Microchimica Acta 184 (8):2731-2738. doi:10.1007/s00604-017-2284-2 2. Sun X-c, Lei C, Guo L, Zhou Y (2016) Sandwich immunoassay for the prostate specific antigen using a micro-fluxgate and magnetic bead labels. Microchimica Acta 183 (8):2385- 2393. doi:10.1007/s00604-016-1889-1 3. 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