Review Cite This: Anal. Chem. XXXX, XXX, XXX−XXX
pubs.acs.org/ac
Quantification of Nanomaterial/Nanomedicine Trafficking in Vivo Liming Wang,† Liang Yan,† Jing Liu,§ Chunying Chen,*,‡ and Yuliang Zhao*,†,‡ †
CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China ‡ CAS Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, China § The College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
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CONTENTS
Challenges in Quantification of Nanomaterial/ Nanomedicine ADME Complex Systems Nanoscale Multicomponent Heterogeneous System Nonequilibrium Processes Endogenous and Exogenous Chemical or Medical Ultramicroquantitative Analysis Multiple Units of NP Concentration Quantification of Nanomaterial/Nanomedicine Trafficking in Vivo Quantification of Nanomaterial/Nanomedicine Absorption in Vivo Accurate and Sensitive Quantification Rapid Detection Quantification of Nanomaterial/Nanomedicine Distribution in Vivo Elemental Analysis-Based Quantification Visual Analysis at Whole-Body and Tissue Levels Integration of Imaging with Elemental Analysis Quantification of Nanomaterial/Nanomedicine Metabolism in Vivo Analysis of Total Amounts and Their Compositions Structural Analysis for Their Chemical Forms Detection of Chemical Events in Situ Quantification of Nanomaterial/Nanomedicine Secretion in Vivo Elemental Analysis-Based Quantification Molecular Spectrometry-Based Quantification Visual Analysis for Clearance Pathways Outlook and Perspective Standardization of Analytical Protocols for Sampling and Sample Preparation of Nano/Bio Interaction Systems Establishment of in Situ Analysis Methods To Track Dynamic Processes of NMs/NPs Improvement of Sensitivity and Resolution of Present Analytical Techniques Development of Labeling Methods with a Simpler and Faster Procedure
© XXXX American Chemical Society
Integration of Different Analytical Methods for Investigating the Fate of Nanomaterials at Multiple Levels Author Information Corresponding Authors ORCID Author Contributions Notes Biographies Acknowledgments References
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bsorption, distribution, metabolism, and excretion (ADME) of nanomaterials (NMs) or nanomedicines (NMs) are fundamental biological processes that dominate their nanomedical functions1−5 or nanotoxicities.6−8 Mostly, NMs exist in biological systems as a form of nanoparticles (NPs). However, determining the composition, spatial distribution, and states of existence of NMs/NPs in vivo, upon entry into the body, as well as monitoring the dynamic changes of this information over time remain a challenge for the current analytical methodologies due to their limited efficiency in characterizing interactions between these complex(nano)−complex(bio) systems. NMs/NPs are more complicated compared with the classic chemical molecules, ions, or elements, while biological systems pose even greater difficulties having a complicated chemical/biological composition, multihierarchical structures, a highly dynamic nature, nonequilibrium states, nonlinear chemical processes, etc. Thus, although some existing methods/protocols have promoted the understanding of how NMs/NPs interact with biological systems, almost none of these are fully adequate for quantitative analyses. Examples of conventional methods used for nano/bio analysis include methods for element quantification which are partially applicable for NMs/NPs, such as atomic spectrometry,9,10 isotopic labeling,11,12 and nuclear analytical methods,13,14 which are useful for elemental identification in determination of accumulation and distributions, and imaging-based methods have facilitated the quantification of NMs/NPs during their in vivo transportation, translocation, and transformation processes.15,16 In the early stage of nanosafety research, a qualitative study of NMs/NPs’ behaviors in vivo was widely
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Special Issue: Fundamental and Applied Reviews in Analytical Chemistry 2018
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DOI: 10.1021/acs.analchem.7b04765 Anal. Chem. XXXX, XXX, XXX−XXX
Analytical Chemistry
Review
Figure 1. Diagram of the ADME processes of NMs/NPs in vivo and summary of the current challenges for their quantitative analysis. NMs/NPs are exposed to human beings mostly through four routes, i.e., oral intake, skin contact, inhalation, and intravenous injection. Upon entering the body, NMs/NPs are quickly distributed into specific organs and then metabolized primarily by the liver. The final excretion of NMs/NPs usually occurs in the liver and kidney in the form of urine and feces. In general, the most important issues regarding the ADME processes of NMs/NPs include: (1) Where do and how much NMs/NPs get in (via absorption)? (2) Where do and how much NMs/NPs go (via distribution)? (3) How much, when do, and what form of NMs/NPs remain intact (via metabolism)? (4) Where do, how much, and what form of NMs/NPs stay in the system (via excretion)? At various stages of the ADME processes, the challenges for in vivo analysis of NMs/NPs may become largely different. Important analytical methods to resolve the analytical challenges for each ADME process are summarized.
and advanced methodology is necessary.13,16,23 Moreover, an adequate method for the characterization and quantification of NMs/NPs’ ADME should also be capable of answering several key fundamental questions: (i) Where do and how much (mass concentration, or particle number concentration) NMs/NPs get in? (ii) Where do and how much NMs/NPs go? (iii) How much, when do, and what form of NMs/NPs remain intact? (iv) Where do, how much, and what form of NMs/NPs stay in the system (Figure 1)? So far, the major difficulties for quantitative analysis of NMs/ NPs’ ADME mainly arise from their unique physical and chemical properties of NMs/NPs and their complex interactions with the biological microenvironment at the nanoscale. Although useful techniques for characterizing NMs/NPs released into the biological microenvironment have been developed,24,25 analytical methods capable of quantitatively tracking NMs/NPs in the complex biological matrices are hardly available. When the analyte is a nanoparticle, usually in solid phase state, the complexities of its quantification greatly expand. For example, an appropriate dose−effect relationship for NMs/NPs often requires the dose information be quantified not only as mass (or molar) concentration but also as particle number concentration or specific surface area. Moreover, when embedded in complex biological matrices, NMs/NPs may release free molecules or ionic components, which must also be considered in the quantification. To explore underlying mechanisms of either nanosafety risk or nanomedical functions, quantitative information on the in vivo dynamic changes in the content, structure, composition, behaviors, and subsequently the
employed which, however, resulted in a lot of inconsistencies or even contradictions among reports on the same NMs/NPs’ safety profile from different laboratories. Recently, it is recognized that quantitative analysis methods are necessary for the accurate characterization of the complicated behaviors of NMs/NPs in vivo. For example, in order to understand the in vivo biological effects of a given nanomaterial, one needs to first monitor the dynamic changes of its components in blood circulation as well as in different organs or tissues to determine key bioparameters such as the half-life,17,18 the composition of the metabolites of the nanomaterial of interest,19 etc. Such understanding requires quantitative methodology to construct a reliably whole spectrum of NMs/NPs’ fate in vivo, which would be essential not only in nanosafety assessment of NMs/NPs but also in the development of their biomedical applications in fields such as cancer nanotechnology. ADME is traditionally used to describe the in vivo pharmacokinetics of chemicals, such as therapeutic drugs, environmental pollutants, and other toxicants.20 Considering ADME of NMs/NPs,21−23 the main differences from the case of classic chemicals mentioned above (molecules, ions, or elements) include that NMs/NPs mostly (i) possess unique structures at nanoscale, (ii) are aggregates of chemicals (molecules, ions, or atoms) to form NPs, (iii) possess high surface reactivity toward the biological matter, and (iv) have multiple components (even for NMs/NPs with a homogeneous chemical composition, their nanosurface may have many adsorbates). Therefore, many analytical techniques used for ADME of conventional chemicals become inadequate with ADME of NMs/NPs, for the study of which, more complicated B
DOI: 10.1021/acs.analchem.7b04765 Anal. Chem. XXXX, XXX, XXX−XXX
spectroscopic methods
methods
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100−400 μm (2D)
200 nm subcellular level (2D and 3D)
FL
PA
70−100 nm (2D and 3D)
SIMS
3 μg mL−1
0.2 pM
1012−1016 atoms cm−3
NMs/NPs with strong near-infrared absorption
fluorescent NMs/NPs
all NMs/NPs
metal- and metalloidbased NMs/NPs
0.7−80 ppm
10 μm (2D)
LA-ICPMS
metal- and metalloidbased NMs/NPs
5−20 nm for size
SP-ICPMS
none
none
ICPMS
metal- and metalloidbased NMs/NPs
none
ICP-OES or ICP-AESa
NMs/NPs applicable metal- and metalloidbased NMs/NPs metal- and metalloidbased NMs/NPs
detection limit 0.002−5 ppb (furnace technique) 1 ppt to 0.5 ppm
0.005 ppt to 10 ppm
none
AAS
spatial resolution
precise quantification and localization of NMs/NPs in cells and tissues high sensitivity
spatial information in 3D without physical sectioning of samples distinction between extracellular and intracellular NMs/NPs’ events colocalization with cellular compartments nondestructiveness
fast sample preparation high temporal resolution (from ms to s)
3D imaging and localization of NMs/NPs in cells or tissues requires a very small amount of sample all elements detectable and isotopes distinguishable nondestructiveness
sufficiently dilutable samples quantitative imaging of the distributions of NMs/NPs in tissues overcome matrix effects all elements detectable isotopes distinguishable quantitative analysis
simultaneous determination of size, size distribution, and number concentration of NMs/NPs quantitative analysis rapid output
high throughput: 5−30 elements/min for ICP-OES and all elements 2−6 min for ICPMS a wide range of elements detectable
accurate elemental determination within cells and tissues quantitative analysis
advantage
Table 1. Analytical Methods for Quantifying the ADME Processes of Nanomaterials/Nanomedicines/Nanoparticles in Vivo limitation
disturbance from the complicated biological background
disturbance from the complicated biological background
quantification not possible attachment of fluorescent probe may change the surface properties of NMs/NPs limitation of tissue penetration of light
bleaching of the fluorophores
the chemical composition of sample must be similar to that of reference material mass interferences and matrix effect
a conducting layer is needed on the NMs/NPs
time-consuming for imaging high consumption of argon
destructiveness
not applicable for NMs/NPs with sizes
