Electronic Supporting Material on the Microchimica Acta Publication

Electronic Supporting Material on the Microchimica Acta publication

Molybdenum Disulfide Quantum Dot Based Highly Sensitive Impedimetric Immunoassay for Prostate Specific Antigen

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

Figure S1: Schematic for the synthesis and bioconjugation of MoS2 QDs along with the development of immunoassay for PSA

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-

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)].

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

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.

2 Figure S4: (a) Raman spectrum of MoS2-QDs and bulk MoS2, (b) XRD spectra of bulk MoS2

& MoS2-QDs, (c) EDX analysis of MoS2-QDs, and (d) FE-SEM analysis of MoS2-QDs

Figure S5: (a) UV-visible spectra of MoS2 QDs and nanosheets and (b) Fluorescence spectrum of MoS2 QDs

3 Figure S6: Current voltage response of Bare SPCE (left) and SPCE/MoS2QD modified (right).

Figure S7: Investigations on the reproducibility of the response of different SPCE/MoS2

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.

4 Figure S8: (a) Selectivity study with the SPCE/MoS2QD/PSAAb electrodes [concentrations of

PSA and other tested proteins were 0.01 and 1 pg⋅mL-1, respectively] and (b) Response of

the SPCE/MoS2QD/PSAAb electrodes with spiked PSA both in standard buffer and serum

samples

Table S1. An overview on recently reported nanomaterial-based methods for determination of PSA

S. Materials used Method Applied Linearity Limit of Specificity Ref. No. range detection

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

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

5 fetoprotein

ng⋅mL−1

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

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]

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

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

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

7 Table S2. PSA detection in spiked serum samples and recovery study

S. No. PSA Concentration Rct (ohms) obtained Rct (ohms) Recovery (%) with standard obtained with samples spiked serum [spiked (ng⋅mL-1)] samples

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

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. Yang J, Wen W, Zhang X, Wang S (2015) Electrochemical immunosensor for the prostate specific antigen detection based on carbon nanotube and gold nanoparticle amplification strategy. Microchimica Acta 182 (9):1855-1861. doi:10.1007/s00604-015-1523-7 4. Liu B, Lu L, Hua E, Jiang S, Xie G (2012) Detection of the human prostate-specific antigen using an aptasensor with gold nanoparticles encapsulated by graphitized mesoporous carbon. Microchimica Acta 178 (1):163-170. doi:10.1007/s00604-012-0822-5 5. Wu D, Liu Y, Wang Y, Hu L, Ma H, Wang G, Wei Q (2016) Label-free electrochemiluminescent immunosensor for detection of prostate specific antigen based on aminated graphene quantum dots and carboxyl graphene quantum dots, Scientific Reports 6, Article number: 20511 6. Yang K, Qi L, Gao Z, Zu X, Chen M (2014) A novel electrochemical immunosensor for prostate-specific antigen based on noncovalent nanocomposite of ferrocene monocarboxylic acid with graphene oxide. Analytical Letters 47(13):2266–2280.

8 7. Mao K, Wu D, Li Y, Ma H, Ni Z, Yu H, Luo C, Wei Q, Du B (2012), Label-free electrochemical immunosensor based on graphene/methylene blue nanocomposite. Analytical Biochemistry 422(1):22-27. 8. Jiao L, Mu Z, Miao L, Du W, Wei Q, Li H (2017) Enhanced amperometric immunoassay for the prostate specific antigen using Pt-Cu hierarchical trigonal bipyramid nanoframes as a label. Microchimica Acta 184(2):423-429. 9. Wang Y, Qu Y, Liu G, Hou X, Huang Y, Wu W, Wu K, Li C (2015) Electrochemical immunoassay for the prostate specific antigen using a reduced graphene oxide functionalized with a high molecular-weight silk peptide. Microchimica Acta 182(11):2061-2067.