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In JoVE (2)
- Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring
- Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs
Other Publications (8)
- Langmuir : the ACS Journal of Surfaces and Colloids
- Journal of Colloid and Interface Science
- Langmuir : the ACS Journal of Surfaces and Colloids
- ACS Nano
- Macromolecular Bioscience
- Journal of Controlled Release : Official Journal of the Controlled Release Society
- Nanotoxicology
- International Journal of Nanomedicine
Articles by Shantanu Balkundi in JoVE
JoVE Bioengineering
Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring
1Department of Radiology, University of Nebraska Medical Center, 2Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center
Bioimaging methods used to assess cell biodistribution of nanoparticles are applicable for therapeutic and diagnostic monitoring of nanoformulated compounds. The methods described herein are sensitive and specific when assessed by histological coregistration. The methodologies provide a translational pathway from rodent to human applications.
JoVE Bioengineering
Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs
Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center
Nanoparticles of indinavir, ritonavir, efavirenz and atazanavir were manufactured using wet milling, homogenization and ultrasonication. These nanoformulations, collectively termed nanoformulated antiretroviral therapy (nanoART), assessed macrophage-based drug delivery. Monocyte-derived macrophage nanoART uptake, retention and sustained release were determined. These preliminary studies suggest the potential of nanoART for clinical use.
Other articles by Shantanu Balkundi on PubMed
Polypeptide Multilayer Films: Role of Molecular Structure and Charge
The role of molecular structure, charge, and hydrophobicity in polyelectrolyte layer-by-layer assembly (LbL) of thin films has been studied using the model polypeptides poly-L-glutamatic acid (PLGA) and poly-L-lysine (PLL), quartz crystal microbalance (QCM), and circular dichroism spectroscopy (CD). The adsorption behavior of PLGA and PLL has been compared with the structure of these molecules in aqueous solution under the same conditions. The data show that the deposition of polypeptide per adsorption step scales with average secondary structure content, whether alpha helix or beta sheet. This is contrary to the expectation based on the view that hydrogen bonds are crucial to polypeptide film assembly, because secondary structure formation in a polypeptide reduces its intermolecular hydrogen-bonding potential. The data also show that polypeptide adsorption scales with ionic strength and chain length. Taken together, the results increase knowledge of polypeptide-based LbL thin film fabrication and will help to provide a firmer foundation for the use of natural or designed polypeptides in LbL.
(-)-Epigallocatechin Gallate/gelatin Layer-by-layer Assembled Films and Microcapsules
A new type of protein/polyphenol microcapsules on the basis of naturally occurring polyphenol (-)-epigallocatechin gallate (EGCG) and gelatin, type A, was obtained using the layer-by-layer (LbL) assembly method. The microcapsules show a more pronounced dependence of permeability on molecular weight of permeating substances than commonly used polyallylamine/polystyrene sulfonate capsules. The regularities of EGCG adsorption in alternation with type A and B gelatins have been investigated using quartz crystal microbalance and electrophoretic mobility measurements on microparticles and found to be dependent on gelatin properties. EGCG in the LbL assemblies retains its antioxidant activity. The kinetics of the reaction of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cation-radicals with films consisting of 1-10 gelatin/EGCG bilayers is affected by film structure. The EGCG content in the protein/polyphenol film material is as high as 30% w/w. Encapsulation of EGCG via its alternated adsorption with gelatins can be a perspective way to new formulations containing the polyphenol for drug delivery applications.
Encapsulation of Bacterial Spores in Nanoorganized Polyelectrolyte Shells
Layer-by-layer assembly uses alternating charged layers of polyionic polymers to coat materials sequentially in a sheath of functionalized nanofilms. Bacterial spores were encapsulated in organized ultrathin shells using layer-by-layer assembly in order to assess the biomaterial as a suitable core and determine the physiological effects of the coating. The shells were constructed on Bacillus subtilis spores using biocompatible polymers polyglutamic acid, polylysine, albumin, lysozyme, gelatin A, protamine sulfate, and chondroitin sulfate. The assembly process was monitored by measuring the electrical surface potential (zeta-potential) of the particles at each stage of assembly. Fluorescent laser confocal microscopy and scanning electron microscopy confirmed the formation of uniform coatings on the spores. The coating surface charge and thickness (20-100 nm) could be selectively tuned by using appropriate polymers and the number of bilayers assembled. The effect of each coating type on germination was assessed and compared to native spores. The coated spores were viable, but the kinetics and extent of germination were changed from control spores in all instances. The results and insight gained from the experiments may be used to design various bioinspired systems. The spores can be made dormant for a desired amount of time using the LbL encapsulation technique and can be made active when appropriate.
Layer-by-Layer-Coated Gelatin Nanoparticles As a Vehicle for Delivery of Natural Polyphenols
Natural polyphenols with previously demonstrated anticancer potential, epigallocatechin gallate (EGCG), tannic acid, curcumin, and theaflavin, were encased into gelatin-based 200 nm nanoparticles consisting of a soft gel-like interior with or without a surrounding LbL shell of polyelectrolytes (polystyrene sulfonate/polyallylamine hydrochloride, polyglutamic acid/poly-l-lysine, dextran sulfate/protamine sulfate, carboxymethyl cellulose/gelatin, type A) assembled using the layer-by-layer technique. The characteristics of polyphenol loading and factors affecting their release from the nanocapsules were investigated. Nanoparticle-encapsulated EGCG retained its biological activity and blocked hepatocyte growth factor (HGF)-induced intracellular signaling in the breast cancer cell line MBA-MD-231 as potently as free EGCG.
Layer-by-layer Nano-encapsulation of Microbes: Controlled Cell Surface Modification and Investigation of Substrate Uptake in Bacteria
LbL nano self-assembly coating of A. vinosum with different polyelectrolyte combinations is presented as an example to investigate substrate uptake in bacteria. The effects of surface charge and the formation of a physical barrier provides new insights in the contact mechanisms between the cell surface and insoluble elemental sulfur. Furthermore, uptake of sulfide by encapsulated cells was investigated. Growth experiments of coated cells showed that surface charge did neither affect sulfide uptake nor the contact formation between the cells and solid sulfur. However, increasing layers slowed or inhibited the uptake of sulfide and elemental sulfur. This work demonstrates how defining surface properties of bacteria has potential for microbiological and biotechnological applications.
Analyses of Nanoformulated Antiretroviral Drug Charge, Size, Shape and Content for Uptake, Drug Release and Antiviral Activities in Human Monocyte-derived Macrophages
Long-term antiretroviral therapy (ART) for human immunodeficiency virus type one (HIV-1) infection shows limitations in pharmacokinetics and biodistribution while inducing metabolic and cytotoxic aberrations. In turn, ART commonly requires complex dosing schedules and leads to the emergence of viral resistance and treatment failures. We posit that the development of nanoformulated ART could preclude such limitations and affect improved clinical outcomes. To this end, we wet-milled 20 nanoparticle formulations of crystalline indinavir, ritonavir, atazanavir, and efavirenz, collectively referred to as "nanoART," then assessed their performance using a range of physicochemical and biological tests. These tests were based on cell-nanoparticle interactions using monocyte-derived macrophages and their abilities to uptake and release nanoformulated drugs and affect viral replication. We demonstrate that physical characteristics such as particle size, surfactant coating, surface charge, and most importantly shape are predictors of cell uptake and antiretroviral efficacy. These studies bring this line of research a step closer to developing nanoART that can be used in the clinic to affect the course of HIV-1 infection.
Pharmacotoxicology of Monocyte-macrophage Nanoformulated Antiretroviral Drug Uptake and Carriage
Limitations inherent to antiretroviral therapy (ART) in its pharmacokinetic properties remain despite over 15 years of broad use. Our laboratory has pioneered a means to improve ART delivery through monocyte-macrophage carriage of nanoformulated drug-encapsulated particles (nanoART). To this end, our prior works sought to optimize nanoART size, charge, and physical properties for cell uptake and antiretroviral activities. To test the functional consequences of indinavir, ritonavir, and efavirenz formulations we investigated relationships between human monocyte and macrophage cytotoxicities and nanoART dose, size, surfactant, and preparation. Wet-milled particles were more cytotoxic to monocytes-macrophages than those prepared by homogenization; with concurrent induction of tumor necrosis factor-alpha. Interestingly, pure suspensions of indinavir and ritonavir at 0.5 mM, and efavirenz at 0.1 mM and 0.5 mM also proved cytotoxic. Individual surfactants and formulated fluconazole neither affected cell function or viability. Although nanoART did not alter brain tight junction proteins ZO-2 and occludin, 0. 5mM ritonavir formulations did alter brain transendothelial electric resistance. These results underscore the potential importance of evaluating the physicochemical and functional properties of nanoART before human evaluations.
Comparative Manufacture and Cell-based Delivery of Antiretroviral Nanoformulations
Nanoformulations of crystalline indinavir, ritonavir, atazanavir, and efavirenz were manufactured by wet milling, homogenization or sonication with a variety of excipients. The chemical, biological, immune, virological, and toxicological properties of these formulations were compared using an established monocyte-derived macrophage scoring indicator system. Measurements of drug uptake, retention, release, and antiretroviral activity demonstrated differences amongst preparation methods. Interestingly, for drug cell targeting and antiretroviral responses the most significant difference among the particles was the drug itself. We posit that the choice of drug and formulation composition may ultimately affect clinical utility.
