Quantifying spectral changes experienced by plasmonic nanoparticles in a cellular environment to inform biomedical nanoparticle design

Foliar Uptake and Distribution of Metallic Oxide Nanoparticles in Maize (Zea mays L.) Leaf

The foliar uptake of Fe3O4, Cr2O3, CuO, and ZnO nanoparticles (NPs) by maize (Zea mays L.) was studied in a lab-scale experiment. The significant increase of Fe concentrations in leaves exposed to Fe3O4 was observed in both stomatal closing and stomatal opening treatments, suggesting the presence of a nonstomatal uptake. In parallel treatments with equal doses of Fe3O4 (∼200 nm), Cr2O3 (∼300 nm), CuO (∼30 nm), and ZnO (∼40 nm) (20-200 μg), the retention percentage of Fe in the leaves (21.0-69.0%) was higher than that of Cr, Cu, and Zn (0.5-14.0%). The steric hindrance effect seems more important for NPs of >200 nm, while hydrophobic surface and negative charge promote the foliar uptake of NPs smaller than 200 nm. The accumulation of NPs in the cuticle was observed through dark-field hyperspectral microscopy. Cr2O3, Fe3O4, and CuO NPs were difficult to penetrate the cuticle. In comparison, ZnO further migrated and distributed within the extracellular space of epidermal and mesophyll cells of the exposed leaf, possibly due to its comparatively higher solubility and hydrophilicity. The findings highlight the potential of the nonstomatal uptake, which might be a critical route for metallic oxide NPs to enter the food chain.

A label-free technique to quantify and visualize gold nanoparticle accumulation at the single-cell level

Despite their wide bioapplications, potential health risks of gold nanoparticles (AuNPs) remain unclear. As a determinant of their risks, AuNP accumulation within a cell population is subject to cell-to-cell heterogeneity. Methods to simultaneously quantify and visualize intracellular AuNPs at the single-cell level are, however, lacking. Here we developed a novel label-free technique, based on hyperspectral imaging with enhanced darkfield microscopy (HSI-DFM), to visualize and quantify AuNP accumulation at the single-cell level. The identification ability of the hyperspectral libraries derived from extra- and intracellular AuNPs was compared. The spectral number in the libraries was optimized to maximize their identification ability while minimizing the identification time. In addition, a filtration method was established to merge spectral libraries from different cell lines based on their similarity. The intracellularly accumulated AuNPs as determined by HSI-DFM well correlated with those detected by inductively coupled plasma mass spectrometry. This validation allowed us to calculate the intracellular concentration of AuNPs at the single-cell level and to monitor the accumulation kinetics of AuNPs in living cells. The label-free method developed herein can be applied to other types of AuNPs differing in their physicochemical properties as well as other NPs, as long as they are detectable by HSI-DFM.

Enhancing nanoparticle accumulation in two dimensional, three dimensional, and xenograft mouse cancer cell models in the presence of docetaxel

Recent clinical trials show docetaxel (DTX), given in conjunction with radiation therapy (RT) and androgen suppression, improves survival in high-risk prostate cancer. Addition of gold nanoparticles (GNPs) to this current DTX/RT protocol is expected to further improve therapeutic benefits remarkably. However, the foundation for the triple combination of RT, DTX, and GNPs must be elucidated to ensure quicker facilitation to the clinic. In this study, we explored the use of low concentrations of DTX combined with GNPs in two prostate cancer cell lines in a two-dimensional monolayer, a three-dimensional spheroid, and a mouse xenograft model. When used together, DTX and GNPs induced a nearly identical relative increase in uptake of gold in both the spheroid model and the mouse xenograft, which saw a 130% and 126% increase respectively after 24 h, showcasing the benefit of using spheroids as an in vitro model to better optimize in vivo experiments. Further, the benefits of using low concentrations of DTX combined with GNPs extended for over 72 h, allowing for less frequency in dosing when translating to the clinic. Overall, these results highlight the benefits of using DTX combined with GNPs and lays the groundwork for the translation of the triple combination of RT, GNPs, and DTX to the clinic.

Hyperspectral-enhanced dark field analysis of individual and collective photo-responsive gold-copper sulfide nanoparticles

We used hyperspectral-enhanced dark field microscopy for studying physicochemical changes in biomaterials by tracking their unique spectral signatures along their pathway through different biological environments typically found in any biomedical application. We correlate these spectral signatures with discrete environmental features causing changes in nanoparticles' physicochemical properties. We use this correlation to track the nanoparticles intracellularly and to assess the impact of these changes on their functionality. We focus on one example of a photothermal nanocomposite, i.e., polymer-coated gold/copper sulfide nanoparticles, because their performance depends on their localized surface plasmon peak, which is highly sensitive to environmental changes. We found spectral differences both in the dependence of time and discrete environmental factors, affecting the range of illumination wavelengths that can be used to activate the functionality of these types of nanoparticles. The presence of proteins (protein corona) and the increase in ionic strength induce a spectral broadening towards the NIR region which we associated with nanoparticles' agglomeration. In acidic environments, such as that of the lysosome, a red shift was also observed in addition to a decrease in the scattering intensity probably associated with a destabilization of the proteins and/or the change in the net charge of the polymer around the nanoparticles. We observed a loss of the photo-excitation potential of those nanoparticles exposed to acidic conditions in the <600 nm spectral rage. In a similar manner, ageing induces a transitioning from a broad multipeak spectrum to a distinct shoulder with time (up to 8 months) with the loss of spectral contribution in the 450-600 nm range. Hence, a fresh preparation of nanoparticles before their application would be recommended for an optimal performance. We highlight the impact of ageing and the acidic environment on the responsiveness of this type of plasmonic nanoparticle. Regardless of the spectral differences found, polymer-coated gold/copper sulfide nanoparticles retained their photothermal response as demonstrated in vitro upon two-photon irradiation. This could be ascribed to their robust geometry provided by the polymer coating. These results should be useful to rationally design plasmonic photothermal probes.

Dark-field/hyperspectral microscopy for detecting nanoscale particles in environmental nanotoxicology research

Nanoscale contaminants (including engineered nanoparticles and nanoplastics) pose a significant threat to organisms and environment. Rapid and non-destructive detection and identification of nanosized materials in cells, tissues and organisms is still challenging, although a number of conventional methods exist. These approaches for nanoparticles imaging and characterisation both inside the cytoplasm and on the cell or tissue outer surfaces, such as electron or scanning probe microscopies, are unquestionably potent tools, having excellent resolution and supplemented with chemical analysis capabilities. However, imaging and detection of nanomaterials in situ, in wet unfixed and even live samples, such as living isolated cells, microorganisms, protozoans and miniature invertebrates using electron microscopy is practically impossible, because of the elaborate sample preparation requiring chemical fixation, contrast staining, matrix embedding and exposure into vacuum. Atomic force microscopy, in several cases, can be used for imaging and mechanical analysis of live cells and organisms under ambient conditions, however this technique allows for investigation of surfaces. Therefore, a different approach allowing for imaging and differentiation of nanoscale particles in wet samples is required. Dark-field microscopy as an optical microscopy technique has been popular among researchers, mostly for imaging relatively large specimens. In recent years, the so-called "enhanced dark field" microscopy based on using higher numerical aperture light condensers and variable numerical aperture objectives has emegred, which allows for imaging of nanoscale particles (starting from 5 nm nanospheres) using almost conventional optical microscopy methodology. Hyperspectral imaging can turn a dark-field optical microscope into a powerful chemical characterisation tool. As a result, this technique is becoming popular in environmental nanotoxicology studies. In this Review Article we introduce the reader into the methodology of enhanced dark-field and dark-field-based hyperspectral microscopy, covering the most important advances in this rapidly-expanding area of environmental nanotoxicology.

Three-Dimensional Tumor Spheroids as a Tool for Reliable Investigation of Combined Gold Nanoparticle and Docetaxel Treatment

Radiotherapy and chemotherapy are the gold standard for treating patients with cancer in the clinic but, despite modern advances, are limited by normal tissue toxicity. The use of nanomaterials, such as gold nanoparticles (GNPs), to improve radiosensitivity and act as drug delivery systems can mitigate toxicity while increasing deposited tumor dose. To expedite a quicker clinical translation, three-dimensional (3D) tumor spheroid models that can better approximate the tumor environment compared to a two-dimensional (2D) monolayer model have been used. We tested the uptake of 15 nm GNPs and 50 nm GNPs on a monolayer and on spheroids of two cancer cell lines, CAL-27 and HeLa, to evaluate the differences between a 2D and 3D model in similar conditions. The anticancer drug docetaxel (DTX) which can act as a radiosensitizer, was also utilized, informing future potential of GNP-mediated combined therapeutics. In the 2D monolayer model, the addition of DTX induced a small, non-significant increase of uptake of GNPs of between 13% and 24%, while in the 3D spheroid model, DTX increased uptake by between 47% and 186%, with CAL-27 having a much larger increase relative to HeLa. Further, the depth of penetration of 15 nm GNPs over 50 nm GNPs increased by 33% for CAL-27 spheroids and 17% for HeLa spheroids. These results highlight the necessity to optimize GNP treatment conditions in a more realistic tumor-life environment. A 3D spheroid model can capture important details, such as different packing densities from different cancer cell lines, which are absent from a simple 2D monolayer model.

Tumor-Selective Immune-Active Mild Hyperthermia Associated with Chemotherapy in Colon Peritoneal Metastasis by Photoactivation of Fluorouracil-Gold Nanoparticle Complexes

Peritoneal metastasis (PM) is considered as the terminal stage of metastatic colon cancer, with still poor median survival rate even with the best recent chemotherapy treatment. The current PM treatment combines cytoreductive surgery, which consists of resecting all macroscopic tumors, with hyperthermic intraperitoneal chemotherapy (HIPEC), which uses mild hyperthermia to boost the diffusion and cytotoxic effect of chemotherapeutic drugs. As HIPEC is performed via a closed circulation of a hot liquid containing chemotherapy, it induces uncontrolled heating and drug distribution in the whole peritoneal cavity with important off-site toxicity and a high level of morbidity. Here, we propose a safer precision strategy using near-infrared (NIR) photoactivated gold nanoparticles (AuNPs) coupled to the chemotherapeutic drug 5-fluorouracil (5-FU) to enable a spatial and temporal control of mild chemo-hyperthermia targeted to the tumor nodules within the peritoneal cavity. Both the 16 nm AuNPs and the corresponding complex with 5-FU (AuNP-5-FU) were shown as efficient NIR photothermal agents in the microenvironment of subcutaneous colon tumors as well as PM in syngeneic mice. Noteworthy, NIR photothermia provided additional antitumor effects to 5-FU treatment. A single intraperitoneal administration of AuNP-5-FU resulted in their preferential accumulation in tumor nodules and peritoneal macrophages, allowing light-induced selective hyperthermia, extended tumor necrosis, and activation of a pro-inflammatory immune response while leaving healthy tissues without any damage. From a translational standpoint, the combined and tumor-targeted photothermal and chemotherapy mediated by the AuNP-drug complex has the potential to overcome the current off-target toxicity of HIPEC in clinical practice.

Laser-induced optothermal response of gold nanoparticles: From a physical viewpoint to cancer treatment application

Gold nanoparticles (GNPs)-based photothermal therapy (PTT) is a promising minimally invasive thermal therapy for the treatment of focal malignancies. Although GNPs-based PTT has been known for over two decades and GNPs possess unique properties as therapeutic agents, the delivery of a safe and effective therapy is still an open question. This review aims at providing relevant and recent information on the usage of GNPs in combination with the laser to treat cancers, pointing out the practical aspects that bear on the therapy outcome. Emphasis is given to the assessment of the GNPs' properties and the physical mechanisms underlying the laser-induced heat generation in GNPs-loaded tissues. The main techniques available for temperature measurement and the current theoretical simulation approaches predicting the therapeutic outcome are reviewed. Topical challenges in delivering safe thermal dosage are also presented with the aim to discuss the state-of-the-art and the future perspective in the field of GNPs-mediated PTT.

Endocytosis-driven gold nanoparticle fractal rearrangement in cells and its influence on photothermal conversion

Cellular endocytosis and intracellular trafficking of nanoparticles induce dynamic rearrangements that profoundly modify the physical properties of nanoparticle and govern their biological outcomes when activated by external fields. The precise structure, organization, distribution, and density of gold nanoparticles (AuNPs) confined within intracellular compartments such as lysosomes have not been studied comprehensively, hampering the derivation of predictive models of their therapeutic activity within the cells of interest. By using transmission electron microscopy and small-angle X-ray scattering, we have determined that canonical spherical citrate-coated AuNPs in the 3-30 nm size range form fractal clusters in endolysosomes of macrophages, endothelial cells, and colon cancer cells. Statistical analysis revealed that the cluster size and endolysosome size are correlated but do not depend on the size of AuNPs unless larger preformed aggregates of AuNPs are internalized. Smaller AuNPs are confined in greater numbers in loose aggregates covering a higher fraction of the endolysosomes compared to the largest AuNPs. The fractal dimensions of intracellular clusters increased with the particle size, regardless of the cell type. We thus analyzed how these intracellular structure parameters of AuNPs affect their optical absorption and photothermal properties. We observed that a 2nd plasmon resonance band was shifted to the near-infrared region when the nanoparticle size and fractal dimensions of the intracellular cluster increased. This phenomenon of intracellular plasmon coupling is not directly correlated to the size of the intralysosomal cluster or the number of AuNPs per cluster but rather to the compacity of the cluster and the size of the individual AuNPs. The intracellular plasmon-coupling phenomenon translates to an efficient heating efficiency with the excitation of the three cell types at 808 nm, transforming the NIR-transparent canonical AuNPs with sizes below 30 nm into NIR-absorbing clusters in the tumor microenvironment. Harnessing the spontaneous clustering of spherical AuNPs by cells might be a more valuable strategy for theranostic purposes than deploying complex engineering to derive NIR-absorbent nanostructures out of their environment. Our paper sheds light on AuNP intracellular reorganization and proposes a general method to link their intracellular fates to their in situ physical properties exploited in medical applications.

Laser-Assisted Delivery of Molecules in Fungal Cells

Fungal infections are becoming a global health problem. A major limiting factor for the development of antifungals is the high impermeability of the rigid and thick fungal cell wall. Compared to mammalian cells, fungal cells are more resilient to perforation due to the presence of this carbohydrate armor. While a few methods have been reported to penetrate the fungal cell wall, such as electroporation, biolistics, glass beads, and the use of monovalent cations, such methods are generally time-consuming, compromise cell viability, and often lead to low permeation rates. In addition, their use remains limited to in vitro applications due to the collateral damage that these techniques could cause to healthy living tissues. Presented in this study is a delivery approach based on the generation of transient breaks, or pores, in the cell wall. Breaks are generated by cavitation and shock waves resulting from the irradiation of gold nanoparticles with a femtosecond infrared laser. Such an approach enabled the delivery of membrane impermeable molecules (i.e., calcein and plasmid DNA) into Saccharomyces cerevisiae, a fungal model organism. This method is expected to exhibit high biocompatibility and holds potential for clinical applications for the treatment of fungal infections given that neither the laser irradiation nor the nanoparticles have been found to damage cells. Mechanistical aspects of photoporation, such as the proximity needed between the nanoparticle and the cell membrane for these processes to take place, are also discussed. Hence, the laser-assisted drug delivery approach described here is suitable for further preclinical evaluation in oral, vaginal, and skin mycoses where current treatments are insufficient due to host-related adverse reactions, poor fungal cell penetration, or risk of developing antifungal resistance.

Photothermal Depletion of Cancer-Associated Fibroblasts Normalizes Tumor Stiffness in Desmoplastic Cholangiocarcinoma

Physical oncology recognizes tissue stiffness mediated by activation of cancer-associated fibroblasts (CAF) and extracellular matrix remodeling as an active modulator of tumorigenesis, treatment resistance, and clinical outcome. Cholangiocarcinoma (CCA) is a highly aggressive and chemoresistant desmoplastic cancer enriched in CAF. CCA's stroma mechanical properties are considered responsible for its chemoresistant character. To normalize tumor mechanics, we propose a physical strategy based on remotely light-activated nanohyperthermia to modulate the tumor microenvironment. In this study, we report the use of multifunctional iron oxide nanoflowers decorated with gold nanoparticles (GIONF) as efficient nanoheaters to achieve complete tumor regression following three sessions of mild hyperthermia. The preferential uptake of GIONF by CAF allowed targeting this cell population, which resulted in a significant early reduction of tumor stiffness followed by tumor regression. In conclusion, our study highlights a spatially and temporally controlled physical strategy, GIONF-mediated photothermal therapy to deplete CAF and normalize the tumor mechanics that may apply to desmoplastic cancer and CCA treatment.

Janus Magnetic-Plasmonic Nanoparticles for Magnetically Guided and Thermally Activated Cancer Therapy

Progress of thermal tumor therapies and their translation into clinical practice are limited by insufficient nanoparticle concentration to release therapeutic heating at the tumor site after systemic administration. Herein, the use of Janus magneto-plasmonic nanoparticles, made of gold nanostars and iron oxide nanospheres, as efficient therapeutic nanoheaters whose on-site delivery can be improved by magnetic targeting, is proposed. Single and combined magneto- and photo-thermal heating properties of Janus nanoparticles render them as compelling heating elements, depending on the nanoparticle dose, magnetic lobe size, and milieu conditions. In cancer cells, a much more effective effect is observed for photothermia compared to magnetic hyperthermia, while combination of the two modalities into a magneto-photothermal treatment results in a synergistic cytotoxic effect in vitro. The high potential of the Janus nanoparticles for magnetic guiding confirms them to be excellent nanostructures for in vivo magnetically enhanced photothermal therapy, leading to efficient tumor growth inhibition.

Assessing the Stability of Fluorescently Encoded Nanoparticles in Lysosomes by Using Complementary Methods

Nanoparticles (NPs) are promising tools in biomedical research. In vitro testing is still the first method for initial evaluation; however, NP colloidal behavior and integrity, in particular inside cells (that is, in lysosomes), are largely unknown and difficult to evaluate because of the complexity of the environment. Furthermore, while the majority of NPs are usually labeled with fluorescent dyes for tracking purposes, the effect of the lysosomal environment on the fluorophore properties, as well as the ensuing effects on data interpretation, is often only sparsely addressed. In this work, we have employed several complementary analytical methods to better understand the fate of fluorescently encoded NPs and identify potential pitfalls that may arise from focusing primary analysis on a single attribute, for example, fluorophore detection. Our study shows that in a lysosomal environment NPs can undergo significant changes resulting in dye quenching and distorted fluorescence signals.

Changes in Optical Properties of Plasmonic Nanoparticles in Cellular Environments are Modulated by Nanoparticle PEGylation and Serum Conditions

When plasmonic nanoparticles (NPs) are internalized by cells and agglomerate within intracellular vesicles, their optical spectra can shift and broaden as a result of plasmonic coupling of NPs in close proximity to one another. For such optical changes to be accounted for in the design of plasmonic NPs for light-based biomedical applications, quantitative design relationships between designable factors and spectral shifts need to be established. Here we begin building such a framework by investigating how functionalization of gold NPs (AuNPs) with biocompatible poly(ethylene) glycol (PEG), and the serum conditions in which the NPs are introduced to cells impact the optical changes exhibited by NPs in a cellular context. Utilizing darkfield hyperspectral imaging, we find that PEGylation decreases the spectral shifting and spectral broadening experienced by 100 nm AuNPs following uptake by Sk-Br-3 cells, but up to a 33 ± 12 nm shift in the spectral peak wavelength can still occur. The serum protein-containing biological medium also modulates the spectral changes experienced by cell-exposed NPs through the formation of a protein corona on the surface of NPs that mediates NP interactions with cells: PEGylated AuNPs exposed to cells in serum-free conditions experience greater spectral shifts than in serum-containing environments. Moreover, increased concentrations of serum (10, 25, or 50 %) result in the formation of smaller intracellular NP clusters and correspondingly reduced spectral shifts after 5 and 10 h NP-cell exposure. However, after 24 h, NP cluster size and spectral shifts are comparable and become independent of serum concentration. By elucidating the impact of PEGylation and serum concentration on the spectral changes experienced by plasmonic NPs in cells, this study provides a foundation for the optical engineering of plasmonic NPs for use in biomedical environments.

A hyperspectral method to assay the microphysiological fates of nanomaterials in histological samples

Nanoparticles are used extensively as biomedical imaging probes and potential therapeutic agents. As new particles are developed and tested in vivo, it is critical to characterize their biodistribution profiles. We demonstrate a new method that uses adaptive algorithms for the analysis of hyperspectral dark-field images to study the interactions between tissues and administered nanoparticles. This non-destructive technique quantitatively identifies particles in ex vivo tissue sections and enables detailed observations of accumulation patterns arising from organ-specific clearance mechanisms, particle size, and the molecular specificity of nanoparticle surface coatings. Unlike nanoparticle uptake studies with electron microscopy, this method is tractable for imaging large fields of view. Adaptive hyperspectral image analysis achieves excellent detection sensitivity and specificity and is capable of identifying single nanoparticles. Using this method, we collected the first data on the sub-organ distribution of several types of gold nanoparticles in mice and observed localization patterns in tumors.

DOI:http://dx.doi.org/10.7554/eLife.16352.001

Metallic elements like gold and silver can be made into particles that are one thousand times smaller than the width of a human hair. Researchers can create these “nanoparticles” in different sizes and shapes that exhibit unique properties. For example, gold can be made into rod-shaped particles that interact with infrared light. Other nanoparticles can be loaded with drug molecules and designed to bind to cancer cells. As a result, nanoparticles have been explored for use in a variety of biomedical imaging and therapy applications. However, we must fully understand how the nanoparticles bind to the cancer cells and how the body tolerates these nanoparticles before they can be used in humans.

Experiments that explore where nanoparticles accumulate in the body are typically called biodistribution studies. However, current techniques for studying biodistribution cannot simultaneously measure the uptake of particles into organs and reveal the fine structures inside the organs that interact with the particles.

SoRelle, Liba et al. aimed to address this problem by developing a new biodistribution technique called HSM-AD (short for hyperspectral microscopy with adaptive detection). This new technique combines a relatively recent method called hyperspectral dark-field microscopy, which can identify nanoparticles from their unique optical signatures, with versatile computer algorithms to detect nanoparticles.

HSM-AD is more sensitive than previously developed biodistribution techniques, and SoRelle, Liba et al. used it to produce highly detailed maps of nanoparticle uptake patterns in the organs of mice. These maps provide new insights into how cells and tissues in the body handle different nanoparticles. Moreover, HSM-AD was able to distinguish nanoparticles with unique shapes by their distinct optical signatures. Further experiments show that HSM-AD can reveal interactions between human tumor cells and nanoparticles specifically designed to target those cells.

HSM-AD will be a useful resource for researchers studying the effect of nanoparticles on the human body. Future studies will use this technique to explore which nanoparticles have the potential to be developed for medical uses.

DOI:http://dx.doi.org/10.7554/eLife.16352.002

High-resolution contrast-enhanced optical coherence tomography in mice retinae

Optical coherence tomography (OCT) is a noninvasive interferometric imaging modality providing anatomical information at depths of millimeters and a resolution of micrometers. Conventional OCT images limit our knowledge to anatomical structures alone, without any contrast enhancement. Therefore, here we have, for the first time, optimized an OCT-based contrast-enhanced imaging system for imaging single cells and blood vessels in vivo inside the living mouse retina at subnanomolar sensitivity. We used bioconjugated gold nanorods (GNRs) as exogenous OCT contrast agents. Specifically, we used anti-mouse CD45 coated GNRs to label mouse leukocytes and mPEG-coated GNRs to determine sensitivity of GNR detection in vivo inside mice retinae. We corroborated OCT observations with hyperspectral dark-field microscopy of formalin-fixed histological sections. Our results show that mouse leukocytes that otherwise do not produce OCT contrast can be labeled with GNRs leading to significant OCT intensity equivalent to a 0.5 nM GNR solution. Furthermore, GNRs injected intravenously can be detected inside retinal blood vessels at a sensitivity of ∼0.5  nM, and GNR-labeled cells injected intravenously can be detected inside retinal capillaries by enhanced OCT contrast. We envision the unprecedented resolution and sensitivity of functionalized GNRs coupled with OCT to be adopted for longitudinal studies of retinal disorders.

A hyperspectral and toxicological analysis of protein corona impact on silver nanoparticle properties, intracellular modifications, and macrophage activation

The inevitable adsorption of biomolecules on nanomaterials results in the formation of a protein corona (PC), which modifies the nanoparticle (NP)–cell interface resulting in modified uptake, activity, clearance, and toxicity. While the physicochemical properties of the NP govern the composition of PC, the formation of PC in turn alters the characteristics of the NP by imparting a new unique “biological” identity. To assess how the PC influences AgNP properties, intracellular modifications, and cellular responses, we utilized a combination of hyperspectral and toxicological analyses. AgNPs were coated with a complex PC (multiple proteins, eg, 10% fetal bovine serum) or a simple PC (single protein, eg, bovine serum albumin [BSA]) and evaluated by hyperspectral and dynamic light scattering for modifications in AgNP properties. Mouse macrophages were exposed to AgNPs with PCs and examined for differences in uptake, cytotoxicity, and cell activation. Hyperspectral imaging revealed intracellular modifications to AgNPs that were found to spectrally match alterations in AgNPs following incubation in lysosomal fluid. Addition of the PC influenced AgNP uptake and cytotoxicity; however, hydrodynamic size and surface charge did not contribute to these responses. Assessments of all endpoints demonstrated differences between complex and BSA PC, suggesting that these responses are not purely driven by the primary protein component of the complex PC (ie, BSA). Alterations in cellular–NP uptake/interactions may be driven through cell surface receptor recognition of protein constituents that make up the PC rather than the physicochemical differences in AgNPs.