Ulli Krull Picture

Ulrich J. Krull

Ph.D. | Professor | Chemistry | Biological and Bioanalytical Chemistry
Email:
ulrich.krull@utoronto.ca
Phone:
905 828 5437
Fax:
905 569 4388
Website:
http://sites.utm.utoronto.ca/krullgroup-csg/
Office Location:
DV3216
Address:
3359 Mississauga Road
Mississauga , Ontario
L5L 1C6

Research Areas:

Nanotechnology and fluidics for bioassays and theranostics

Krull Research Picture

Research Profile:

Luminescence from nanoparticles (NPs) can be used to interrogate selective interactions at the surface of the nanoparticles by means of resonance energy transfer to a fluorescent label that serves to transduce a binding interaction. Selectivity can be established using immobilized biomolecules on nanoparticles for interaction with proteins, peptides and nucleic acid sequences. Multiplexed solid-phase bioassays on paper-based platforms would be useful technology for rapid detection of markers for pathogens and genetically-based disease. Samples can be manipulated using microfluidics for extraction, concentrating and delivery to the detection system. Our exploration of a combination of various approaches to achieve signal enhancement have allowed use of cell phone cameras as spectrally-selective detectors. We are also exploring the use of upconversion for the photo-controlled intracellular release of drugs. In this approach the NP acts as a platform to cage the therapeutic compound, and to convert near-infrared excitation light to UV-vis emission for photolytic cleavage. The therapeutic compound can be released while the NP concurrently provides the capability to bioassay molecular markers in the sample.

Courses Taught:

CHM414H5 (undergraduate); CHM1103H, CHM1105H, CHM1152H, CHM1157H (graduate)

Publications

Recent:

T. Nguyen, A. Sedighi, U.J Krull and C. Ren, A multi-functional droplet microfluidic platform for rapid immobilization of oligonucleotides on semiconductor quantum dots, ACS Sensors, 5: 746-753, 2020.

A. Sedighi and U.J. Krull, Enhanced immunoassay using a rotating paper platform for quantitative determination of low abundance protein biomarkers, Analytical Chemistry, 91: 5371-5379, 2019.

A. Shahmuradyan, M. Moazami-Goudarzi, F. Litazume, G.S. Espie and U.J. Krull, Paper-based platform for detection by hybridization using intrinsically labeled fluorescent oligonucleotide probes on quantum dots, The Analyst, 144: 1223-1229, 2019.

P. Das, A. Sedighi and U.J. Krull, Cancer biomarker determination by resonance energy transfer using functional fluorescent nanoprobes, Analytica Chimica Acta, 1041: 1-24, 2018.

K. Malhotra, M. Omair Noor and U.J. Krull, Detection of Cystic Fibrosis transmembrane  conductance regulator ∆F508 gene mutation using a paper-based nucleic acid hybridization assay and a smartphone camera, The Analyst, 143: 3049-3058, 2018.

T.H. Nguyen, X. Chen, A. Sedighi, U.J. Krull and C.L. Ren, A droplet-based microfluidic platform for rapid immobilization of quantum dots on individual magnetic microbeads, Microfluidics and Nanofluidics, 22, Issue 6, Article number 63, 2018.

A.Sedighi and U.J. Krull, Enzymatic amplification of oligonucleotides in paper substrates, Talanta, 186: 568-575, 2018.

Y. Han Y. Han, M.O. Noor, A. Sedighi, U. Uddayasankar, S. Doughan and U.J. Krull, Inorganic Nanoparticles as Donors in Resonance Energy Transfer for Solid-Phase Bioassays and Biosensors, Langmuir, 33: 12839-12858, 2017 (selected for front cover of  journal).

P. Das and U.J. Krull, Detection of cancer biomarker protein on modified cellulose paper by fluorescence using aptamer-linked quantum dots, The Analyst, 142: 3132-3135, 2017.

A. Sedighi and U.J. Krull, Rapid Immobilization of Oligonucleotides at High Density on Semiconductor Quantum Dots and Gold Nanoparticles, Langmuir, 32: 13500-13509, 2017.

S. Doughan, U. Uddayasankar, A. Peri and U.J. Krull, A Paper-Based Multiplexed Resonance Energy Transfer Nucleic Acid Hybridization Assay Using a Single Form of Upconversion Nanoparticle as Donor and Quantum Dots as Acceptors, Analytica Chimica Acta, 962: 88-96, 2017.

Q. Ju, M.O. Noor and U.J. Krull, Paper-based biodetection using luminescent nanoparticles, Analyst, 141: 2838-2860, 2016.

S. Doughan, M.O. Noor, Y. Han and U.J. Krull, Resonance Energy Transfer-Based Nucleic Acid Hybridization Assays on Paper-Based Platforms Using Emissive Nanoparticles as Donors, Methods in Molecular Biology, 1571: 301-326, 2017 (invited).

A. Shahmuradyan and U.J. Krull, Intrinsically Labeled Fluorescent Oligonucleotide Probes on Quantum Dots for Transduction of Nucleic Acid Hybridization, Analytical Chemistry, 88, 6: 3186-3193, 2016.

F. Zhou, M.O. Noor and U.J. Krull, A paper-based sandwich format hybridization assay for unlabeled nucleic acid detection using upconversion nanoparticles as energy donors in luminescence resonance energy transfer, Nanomaterials, 5: 1556-1570, 2015.

U. Uddayasankar and U.J. Krull, Energy Transfer Assays Using Quantum Dot-Gold Nanoparticle Complexes: Optimizing Oligonucleotide Assay Configuration Using Monovalently Conjugated Quantum Dots, Langmuir, 31: 8194-8204, 2015.

M.O. Noor, D, Hrovat, M. Moazami-Goudarzi, G.S. Espie and U.J. Krull, Ratiometric Fluorescence Transduction by Hybridization after Isothermal Amplification for Determination of Zeptomole Quantities of Oligonucleotide Biomarkers with a Paper-Based Platform and Camera-Based Detection, Analytica Chimica Acta, 885: 156-165, 2015.

S. Doughan, U. Uddayasankar and U.J. Krull, A paper-based resonance energy transfer nucleic acid hybridization assay using upconversion nanoparticles as donors and quantum dots as acceptors, Analytica Chimica Acta, 878:1-8, 2015 (selected for cover page as featured article).

U. Uddayasankar, R.T. Shergill and U.J. Krull, Evaluation of nanoparticle-ligand distributions to determine nanoparticle concentration, Analytical Chemistry, 87:1297-1305, 2015.