The intracellular environment can be described as crowded, complex, and confined, where biomacromolecules with characteristic dimensions of 1-10’s of nm are present at high concentration, and where membranes, organelles, and filamentous matrices restrict motion. Although important in designing nanoparticles for biomedical applications, understanding of the transport of nanoparticles in such environments remains limited. Our group has developed methods based on magnetic measurements of nanoparticle rotation that can assess nanoparticle stability and mobility in complex fluid environments, including biological fluids. This approach requires small sample volumes (~20 μl), low concentrations of nanoparticles (~0.02% v/v), and does not require optic access to the sample. Work has demonstrated that this technique is quantitatively accurate, can provide insight into novel nanoscale phenomena, and can be used to assess the interaction of nanoparticles and proteins in situ at physiologically-relevant concentrations. These findings pave the way towards improved understanding of nanoparticle transport in complex fluid environments relevant to biomedical applications.

Related Publications:

• Andreina Chiu Lam^G, Edward Staples, Carl Pepine, and Carlos Rinaldi, “Perfusion, cryopreservation, and nanowarming of whole hearts using colloidally stable cryopreservation agent solutions.” Science Advances, 7(2):eabe3005, 2021. [https://doi.org/10.1126/sciadv.abe3005]
• Brittany Partain, Mythreyi Unni^G, Jon Dobson, Carlos Rinaldi, and Kyle Allen, “The Clearance and Biodistribution of Magnetic Composite Nanoparticles in Healthy and Osteoarthritic Rat Knees.” Journal of Controlled Release, 321:259-271, 2020. [https://doi.org/10.1016/j.jconrel.2020.01.052]
• Kaarjel K. Narayanasamy, Melissa Cruz-Acuña^G, Carlos Rinaldi, James Everett, Jon Dobson, and Neil D. Telling, “AC susceptibility as a particle-focused probe of coating and clustering behavior in magnetic nanoparticle suspensions.” Journal of Colloid and Interface Science, 352:536-545, 2018. [http://doi.org/10.1016/j.jcis.2018.08.014]
• Ana C. Bohorquez^G, Mythreyi Unni^G, Sayali Belsare^G, Andreina Chiu Lam^G, Lori Rice, Christine Pampo, Dietmar Siemann, and Carlos Rinaldi, “Stability and mobility of magnetic nanoparticles in biological environments determined from dynamic magnetic susceptibility measurements.” Bioconjugate Chemistry, 29(8):2793-2805, 2018. [http://doi.org/10.1021/acs.bioconjchem.8b00419]
• Ana C. Bohorquez^G, Chuncheng Yang^F, Donald Bejleri^G, and Carlos Rinaldi, “Rotational diffusion of magnetic nanoparticles in protein solutions.” Journal of Colloid and Interface Science, 506:393-402, 2017. [http://doi.org/10.1016/j.jcis.2017.07.009]
• Yash Y. Shah, Lorena Maldonado-Camargo^G, Neal S. Patel, Adam H. Biedrzycki, Elena G. Yarmola, Jon Dobson, Carlos Rinaldi, Kyle D. Allen, “Magnetic Particle Translation as a Surrogate Measure for Synovial Fluid Mechanics.” Journal of Biomechanics, 60:9-14, 2017. [http://doi.org/10.1016/j.jbiomech.2017.05.015]
• Rishit R. Merchant^G, Lorena P. Maldonado-Camargo^G, and Carlos Rinaldi, “In situ measurements of dispersed and continuous phase viscosities of emulsions using nanoparticles.” Journal of Colloid and Interface Science, 486:241-248,2017. [http://doi.org/10.1016/j.jcis.2016.09.063]
• Lorena P. Maldonado-Camargo^G, Chuncheng Yang^F, and Carlos Rinaldi, “Scale-dependent rotational diffusion of nanoparticles in polymer solutions.” Nanoscale, 9(33):12039-12050, 2017. [http://doi.org/10.1039/C7NR01603D]
• Lorena P. Maldonado-Camargo^G and Carlos Rinaldi, “Breakdown of the Stokes-Einstein relation for the rotational diffusivity of polymer grafted nanoparticles in polymer melts.” Nano Letters, 16:6767-6773, 2016. [http://doi.org/10.1021/acs.nanolett.6b02359]
• Lorena P. Maldonado-Camargo^G, Isaac Torres-Díaz^P, Maria E. Hernández, and Carlos Rinaldi, “Estimating the contribution of Brownian and Néel relaxation in a magnetic fluid through dynamic magnetic susceptibility measurements.” Journal of Magnetism and Magnetic Materials, 412:223-233,2016. [http://doi.org/10.1016/j.jmmm.2016.03.087]
• Sergio Sierra-Bermudez^G, Lorena P. Maldonado-Camargo^G, Francois Orange, Maxime Guinel, and Carlos Rinaldi, “Assessing magnetic nanoparticle aggregation in polymer melts by dynamic magnetic susceptibility measurements,” Journal of Magnetism and Magnetic Materials, 378:64-72, 2015. [http://doi.org/10.1016.j.jmmm.2014.10.171]
• Edwin de la Cruz-Montoya^G and Carlos Rinaldi, “Preparation of magnetic polymer colloids with Brownian magnetic relaxation,” Colloid and Polymer Science, 292:1191-1198,2014. [http://doi.org/10.1007/s00396-014-3163-6]
• Ana C. Bohorquez^G and Carlos Rinaldi, “In situ evaluation of nanoparticle-protein interactions by dynamic magnetic susceptibility measurements,” Particle & Particle Systems Characterization, 31(5):561-570,2014. [http://doi.org/10.1002/ppsc.201300296]
• Adriana P. Herrera^G, Liliana Polo-Corrales^G, and Carlos Rinaldi, “Influence of aging time of oleate precursor on the magnetic relaxation of cobalt ferrite nanoparticles synthesized by the thermal decomposition method.” Journal of Magnetism and Magnetic Materials, 328:41-52, 2013. [http://doi.org/10.1016/j.jmmm.2012.09.069]
• Javier Tafur, Adriana P. Herrera^G, Carlos Rinaldi, Eduardo J. Juan, “Development and validation of a 10kHz-1MHz AC magnetic susceptometer with constant excitation field.” Journal of Applied Physics, 111:07E349, 2012. [http://doi.org/10.1063/1.3680200]
• Victoria L. Calero^G, Darlene I. Santiago^G, and Carlos Rinaldi, “Quantitative nanoscale viscosity measurements using magnetic nanoparticles and SQUID AC susceptibility measurements.” Soft Matter, 7(9):4497-4503, 2011. [http://doi.org/10.1039/C0SM00902D]
• Adriana P. Herrera^G, Carola Barrera^G, Yashira Zayas^U, and Carlos Rinaldi, “Monitoring colloidal stability of polymer-coated magnetic nanoparticles using AC susceptibility measurements.” Journal of Colloid and Interface Science, 342(2): 540-549, 2010. [http://doi.org/10.1016/j.jcis.2009.10.041]
• Carola Barrera^G, V. Florian-Algarín, Aldo Acevedo-Rullán, and Carlos Rinaldi, “Monitoring gelation using magnetic nanoparticles.” Soft Matter, 6(15):3662-3668, 2010. [http://doi.org/10.1039/c003284k]