Fluorescence Bioimaging Research Articles

Femtosecond Laser Synthesis of Carbon Dots from Amino Acids for Fluorescent Bioimaging and Sensing

Femtosecond Laser Synthesis of Carbon Dots from Amino Acids for Fluorescent Bioimaging and Sensing

Novel förster resonance energy transfer (FRET)-based ratiometric fluorescent probe for detection of cyanides by nucleophilic substitution of aromatic hydrogen (SNArH)

The development of novel fluorescent probes for real-time detection of cyanides (CN−) in environmental and biological systems has become a significant focus in chemical sensing. Particularly, ratiometric fluorescence sensing offers a unique method for precise and quantitative detection of cyanides, even under complex conditions. We report herein the design of a new ratiometric fluorescent probe for cyanides based on modulation of Förster resonance energy transfer (FRET) coupled with novel cyanide-induced nucleophilic substitution of aromatic hydrogen (SNArH). The target probe (R1) is developed by introducing coumarin fluorophores as FRET donors into a 3-nitro-naphthalimide acceptor, which is easily synthesized and exhibits a colorimetric change from colorless to faint yellow and a significant ratiometric fluorescence shift (Δλ = 114 nm) upon cyanide binding. A clear ratiometric signal at I582/I468 was obtained, with a limit of detection of 5.69 μM. The sensing mechanism was confirmed through 1H NMR titration and LC-MS analysis. Additionally, R1-loaded strips were easily prepared, serving as a portable device for detecting CN− with visible color changes. The probe R1 has been successfully utilized for real-time monitoring of cyanide in food materials and water samples. Importantly, fluorescence bioimaging studies in HeLa cells were conducted, demonstrating the probe’s capability for ratiometric detection of exogenous CN− in living systems.

A novel HER2-specific sensor based on DARPin_9–29 and albumin binding domain for real-time fluorescence-guided tumor detection in animal model of cancer

In animal models of cancer, targeted fluorescence bioimaging, performed non-invasively and in real time, is indispensable tool for assessing tumor location, spread of metastasis, and the therapeutic potential of anticancer drugs under development.To overcome the limitation of antibodies in bioimaging applications, small artificial scaffold proteins based on ankyrin repeats (DARPins, designed ankyrin repeat proteins) are used as tumor-associated antigen binders. In this study for the first time, we assessed the potential of DARPin_9–29, the human epidermal growth factor receptor 2 (HER2) subdomain I-specific protein, genetically fused with albumin binding domain (ABD) and conjugated with Cyanine5.5 as a NIR sensor for fluorescence bioimaging of HER2-positive cancer in animal model.In vivo biodistribution studies have revealed sufficient tumor-to-background ratios at 48 h (3.17 ± 0.55) and 72 h (3.49 ± 0.64) postinjection, providing excellent contrast between the primary tumor and tissue background and allowing clear breast tumor detection. Ex vivo biodistribution has shown that ABD module in DARP-ABD sensor prevents renal reabsorption and increases tumor accumulation in more than 10-folds compared to excreting organs.To verify if DARP-ABD-Cy5.5 can demarcate HER2-positive tumor in vivo, HER2-positive syngeneic breast cancer cell line with constitutive gene expression of luciferase eFFLuc, was created. The powerful combination of bioluminescence and fluorescence imaging let to track the fluorescent anti-HER2 DARP-ABD sensor in bioluminescent HER2-positive breast tumors.Our results validate DARP-ABD as a promising sensor for fluorescence-guided imaging of HER2-positive solid cancer, which can be used in the development of improved anticancer treatment strategies.

Optical Transparency Windows in Near-Infrared and Short-Wave Infrared for the Skin, Skull, and Brain: Fluorescence Bioimaging Using PbS Quantum Dots.

Fluorescence imaging (FI) employing near-infrared (NIR) light within the range of ~750-1350 nm enables biomedical imaging several millimeters beneath the tissue surface. More recent investigations into the short-wave IR (SWIR) transparency windows between ~1550-1870 and 2100-2300 nm highlight their superior capabilities. This research presents a comparison of IR-FI of PbS quantum dots, emitting at 990, 1310, and 1580 nm, through the mouse scalp skin, skull, and brain. The SWIR fluorescence is the most effectively transmitted signal, showing particularly significant enhancement when passing through the skull, which causes high light scattering. For the analysis of the imaging results and light propagation through the organs, their spectra of attenuation, absorption, and scattering coefficients are measured. In view of biomedical imaging, attenuation due to light scattering is a more destructive factor. Hence, the spatial resolution and imaging contrast can be improved by operating in SWIR due to decreased light scattering.

Fabrication of albumin-Ti3C2 MXene quantum dots-based nanohybrids for breast cancer imaging and synergistic photo/chemotherapeutics

Advancement in the development of new materials with theranostic and phototherapeutic potential along with receptiveness to external stimuli has been persistently inspiring oncology research. Herein, titanium carbide-based MXene quantum dots (FHMQDs) have been synthesized and modified to take advantage of stimuli-responsive behavior and target specificity for breast cancer cells. With a size of around 3 nm, the developed FHMQDs demonstrate high fluorescent emission at around 460 nm. With ∼90 % encapsulation efficiency of doxorubicin (DOX), the developed system also offers rapid DOX release behavior when encountering an acidic pH (5.4). Further, the in vitro assessment of the developed FHMQDs on MDA-MB 231 breast cancer cells presents excellent target specificity to cancer cells which was reflected by its high cytotoxicity against cancer cells. Additionally, the outstanding photodynamic efficiency of FHMQDs due to excessive Reactive Oxygen Species (ROS) generating ability along with apoptosis promoting capability of FHMQDs in cancer cells demonstrates a synergistic approach in cancer theranostics. Encouragingly, the fabricated FHMQDs also exhibited fluorescent labelling and bioimaging capacity which makes it an incredible platform that ensures theranostic excellence in breast cancer research.

Rhodamine 6G-PAH probes for heavy metal: Fluorescence detection, bioimaging, and solid-phase sensing application

Four rhodamine 6G-PAH probes with pyrene (R6G-Pyr), anthracene (R6G-Ant), acenaphthene (R6G-Acp) or phenanthrene (R6G-PA) as fluorophore were designed and synthesized for Hg(II) detection. Probe R6G-PA, which had the lowest detection limit of 0.84 nmol/L, displayed the best fluorescence performance as compared to the other three probes. This type of probe had good anti-interference properties against most common metal ions except Cu(II). Metal Cu(II) had a certain quenching effect on the fluorescence generated by Hg(II), with a minimum detection limit of 0.31 nmol/L (for R6G-Acp), indicating its potential practicability for Cu(II) detection. The structure-fluorescence relationship was discussed based on density functional theory (DFT) calculations, and R6G-PA + Hg(II), which had the minimum dihedral angle between polycyclic aromatic rings and rhodamine spiro ring, produced the strongest π-π accumulation and provided the brightest fluorescence. Probe R6G-PA was successfully employed for fluorescence detection of Hg(II) in biological samples. Its solid-phase sensor PS@R6G-PA was developed by immobilizing R6G-PA on PS microspheres for the determination of Hg(II) in water and food samples, with excellent reproducibility and fluorescence “on/off” response. The relative error of the spiked recovery rate was less than 10 %.

The potential of carbon dots produced from mangosteen through green synthesis for induced-cell proliferation and fluorescence bioimaging

The potential of carbon dots produced from mangosteen through green synthesis for induced-cell proliferation and fluorescence bioimaging

Heavy-atom-free π-twisted photosensitizers for fluorescence bioimaging and photodynamic therapy.

As the field of preclinical research on photosensitizers (PSs) for anticancer photodynamic therapy (PDT) continues to expand, a focused effort is underway to develop agents with innovative molecular structures that offer enhanced targeting, selectivity, activation, and imaging capabilities. In this context, we introduce two new heavy-atom-free PSs, DBXI and DBAI, characterized by a twisted π-conjugation framework. This innovative approach enhances the spin-orbit coupling (SOC) between the singlet excited state (S1) and the triplet state (T1), resulting in improved and efficient intersystem crossing (ISC). Both PSs are highly effective in producing reactive oxygen species (ROS), including singlet oxygen and/or superoxide species. Additionally, they also demonstrate remarkably strong fluorescence emission. Indeed, in addition to providing exceptional photocytotoxicity, this emissive feature, generally lacking in other reported structures, allows for the precise monitoring of the PSs' distribution within specific cellular organelles even at nanomolar concentrations. These findings underscore the dual functionality of these PSs, serving as both fluorescent imaging probes and light-activated therapeutic agents, emphasizing their potential as versatile and multifunctional tools in the field of PDT.

Application of novel AIE materials in fluorescence probes

Fluorescence bioimaging is considered an indispensable technique in biological research due to its high sensitivity, excellent spatial and temporal resolution, non-invasiveness, rapid and real-time responsiveness, as well as its ease of accessibility. Among these, fluorescence probes play a pivotal role in fluorescence imaging technology thanks to their strong specificity, high sensitivity, rapid response, and straightforward implementation. Aggregation-Induced Emission (AIE) molecules exhibit a unique phenomenon: they emit weak or no fluorescence when dissolved in a solution but become highly luminescent under aggregated/clustering conditions. Leveraging this, fluorescent probes with AIE characteristics often demonstrate fluorescence activation under conditions of spontaneous aggregation or binding with analytes, showcasing high sensitivity and exceptional signal-to-noise ratios. Consequently, fluorescence probes based on the distinctive optical properties of AIE hold immense potential for applications in fluorescence bioimaging. This paper primarily investigates the synthesis properties and applications in biosensing of a series of novel organic fluorescence probes with aggregation-induced emission (AIE) characteristics. By synthesizing a range of compounds with AIE properties and experimentally determining their photophysical properties and molecular structures, the study explores the potential applications of these compounds in DNA recognition, protein detection, small molecule recognition, cellular pH detection, and bioimaging.

(Invited) Quantitative in Vitro/In Vivo Fluorescence Bioimaging with Graphene Quantum Dots

Graphene Quantum Dots (GQDs) are novel carbon nanomaterials consisting of few layers of partially functionalized graphitic carbon. Their nanometer-scale size together with functional groups render GQDs more water soluble and biocompatible than many other nanocarbon constructs. Like many nanocarbons, GQDs possess structure-dependent optical properties, exhibiting confinement-defined fluorescence in the visible and defect-originated emission in the near-infrared (NIR). These properties give GQDs a certain advantage for applications in therapeutic tracking, imaging, analyte detection and targeted drug/gene delivery. In addition to tracing the location of therapeutic or analyte, GOD fluorescence allows for several modes of quantitative assessment within these applications. In vitro it is utilized to evaluate relative amounts of therapeutics or analytes present within the cells at a certain time period. In vivo NIR emission of the GQDs-based sensors implanted under the skin can help detect trace quantities of analyte in the body, while their NIR fluorescence in animal organs can quantify relative therapeutic uptake over time.The present work introduces novel studies and analytical tools exploring and enhancing such imaging modalities. Although GQD in vitro fluorescence microscopy imaging is often used to quantitate their (and payload) uptake and excretion, this method suffers from multiple discrepancies including the analysis of dead cells, cellular debris and non-internalized nanomaterials, and can be also time and resource-consuming. Our work aiming to circumvent these issues utilizes Artificial Intelligence (AI) approach to provide more accurate quantification of the uptake/excretion of the GQDs and their payload. In this application the AI algorithms developed in house do not only optimize the imaging, but also provide automated image analysis streamlining the assessment of a variety of GQD biomedical applications including therapeutic delivery and targeting. In vivo quantitative animal imaging with several different types of GQDs, from pristine to doped with rare earth metals for NIR fluorescence enhancement, is performed to evaluate GQD organ accumulation over time. Defect or dopant-originated NIR GQD fluorescence in the range of 900 – 1060 nm due to its high penetration depth can be observed from the organs of sedated live mice and utilized for GQD uptake tracking. NIR imaging of the excised organs allows for quantitative biodistribution assessment with further microscopic confirmation of the GQD content in organ tissue slices. Quantitative optical imaging and analysis presented in this work for GQDs can aid the further advancement of these novel nanomaterials in therapeutic delivery and analyte detection applications in vitro and in vivo.

Milk Exosome-Glow Nanosystem for Cancer Cellular and Tissue Bioimaging.

Milk-derived exosomes are widely used for diagnosis, delivery, imaging, and theranostic applications. Near-Infrared (NIR) based fluorescence bioimaging is an attractive and safer technique that is used for clinical applications. However, almost all NIR imaging agents tend to have poor photostability, short half-life, nonspecific protein binding, and concentration-dependent aggregation(s). Therefore, there is an unmet clinical need to develop newer and safer modalities to package and deliver NIR imaging agents. Bovine milk exosomes are natural, biocompatible, safe, and efficient nanocarriers that facilitate the delivery of micro- and macromolecules. Herein, we developed an exosome-based NIR dye loaded nanoimaging formulation that offers improved solubility and photostability of NIR dye. Following the acetic acid based extracellular vesicle (EV) treatment method, we extracted the bovine milk exosomes from a variety of pasteurized grade milk. The EVs were screened for their physicochemical properties such as particle size and concentration and zeta potential. The stability of these exosomes was also determined under different conditions, including storage temperatures, pH, and salt concentrations. Next, indocyanine green, a model NIR dye was loaded into these exosomes (Exo-Glow) via a sonication method and further assessed for their improved fluorescence intensity and photostability using an IVIS imaging system. Initial screening suggested that size of the selected bovine milk exosomes was ∼100-135 nm with an average particle concentration of 5.8 × 102 particles/mL. Exo-Glow further demonstrated higher fluorescence intensity in cancer cells and tissues when compared to free dye. These results showed that Exo-Glow has the potential to serve as a safer NIR imaging tool for cancer cells/tissues.

Efficient Near-Infrared Fluorophores Based on Cyanostyrene Derivatives for Two-Photon Fluorescence Bioimaging.

Organic fluorescent materials with red/near-infrared (NIR) emission are highly promising for use in biotechnology due to their exceptional advantages. However, traditional red/NIR fluorophores often exhibit weak emission at high concentrations or in an aggregated state due to the aggregate-caused quenching effect, which severely limits their applicability in biological imaging. To address this challenge, we developed a series of cyanostyrene derivatives with aggregation-induced emission characteristics, including 2,3-Bis-(4-styryl-phenyl)-but-2-enedinitrile (DPB), 2,3-Bis-{4-[2-(4-methoxy- phenyl)-vinyl]-phenyl}-but-2-enedinitrile (DOB), 2,3-Bis-{4-[2-(4-diphenylamino- phenyl)-vinyl]-phenyl}-but-2-enedinitrile (DTB), and 2,3-Bis-[4-(2-{4-[phenyl- (4-triphenylvinyl-phenyl)-amino]-phenyl}-vinyl)- phenyl]-but-2-enedinitrile (DTTB). Notably, these compounds exhibited intense solid state fluorescence owing to AIE effect, especially DTTB shows NIR emission with high solid state quantum efficiency (712 nm, ΦF=14.2 %). Then we prepared DTTB@PS-PEG NPs nanoparticles by encapsulating DTTB with the amphiphilic polymer polystyrene-polyethylene glycol (PS-PEG). Importantly, DTTB@PS-PEG NPs exhibited highly efficient NIR luminescence (ΦF=28.7 %) and a large two-photon absorption cross-section (1900 GM) under 800 nm laser excitation. The bright two-photon fluorescence of DTTB@PS-PEG indicated that it can be a highly promising candidate for two-photon fluorescence probe. Therefore, this work provides valuable insights for the design of highly efficient and NIR-emitting two-photon fluorescent probes.

Development of in vitro and in vivo c-Met targeted dual-modal nanoprobes for NIR II fluorescent bioimaging and magnetic resonance imaging of breast carcinoma metastasis

Because of the conventional bioimaging methods, including ultrasound and X-ray examinations often lack accuracy and sensitivity in the early diagnosis, as a heterogeneous subtype of breast cancer, it remains an urgent need to develop efficaciously and sensitively diagnostic drivers of triple negative breast cancer (TNBC). The overexpression of c-mesenchymal epithelial transition-factor (c-Met) is associated with the basal subtype of breast carcinoma and linked with decreased survival rate of TNBC patients. Here, we have synthesized a dual-modal nanoprobe with luminescence imaging in the bio-window of near infrared II region (NIR II, 1000–1700) and magnetic resonance imaging (MRI) performances. After c-Met targeting binding protein decoration, this Fe3O4@mSiO2-ICG/cMBP had outstanding size stability and preeminent biocompatibility. Meaningfully, it presented effective TNBC cells recognition in vitro. Besides, after caudal-vein injection of this nanoprobe, both NIR II luminescence imaging and MRI demonstrated that it can more efficiently concentrated in metastatic TNBC tumors in comparison with Fe3O4@mSiO2-ICG and clinical used Gd-DTPA. Meanwhile, the core–shell nanoprobes also showed negligible toxicity in vivo. All results suggested that our cMBP modified nanocomposite could provide a fascinating and efficient non-invasive diagnostic tool for TNBC detection in clinic.

Ratiometric detection and monitoring of cyanide in biological, environmental and food samples by a novel triphenylamine-xhantane based fluorescent probe

BackgroundAs cyanide (CN−) is a significant hazard to the environment and human health, it is essential to monitor cyanide levels in water and food samples. Moreover, real-time visualization of CN−could provide an additional understanding of its critical physiological and toxicological roles in living cells. The fluorescence approach based on small organic probes is an effective way for the detection of CN−. In this approach, a triphenylamine-xhantane conjugate was applied to detect in many samples such as sewage water, soil, sprouted potato, apricot seed, and living cells. ResultsWe report a new ratiometric near-infrared fluorescent probe based on a triphenylamine-xhantane derivative for CN−sensing in many samples. The probe displays high selectivity for only CN− ions among a series of analytes. The addition of cyanide to the dicyanovinyl moiety of the probe disrupts π-conjugation followed by the interruption of internal charge transfer. Consequently, the emission peak of the probe shifts hypsochromically from 655 to 495 nm. There is a linear correlation between the emission intensity (I495) and cyanide level, with a detection limit of 0.036 μM. The probe has many advantages over many probes, such as NIR fluorescence, ratiometric response, low cytotoxicity (85.0 % cell viability up to 50.0 μM of the probe), good membrane permeability, fast response time (4.0 min), high selectivity, good photostability, and anti-interference capability. SignificanceAlthough various probes have been reported in the literature, the use of triphenylamine-xhantane unit as CN− probe has yet to be explored. The probe can detect trace levels of cyanide in many samples such as sewage water, soil, sprouted potatoes, and apricot seeds. Furthermore, it is successfully utilized for the ratiometric fluorescent bioimaging of cyanide in living cells.

Structurally Modulated Formation of Cyanine J-Aggregates with Sharp and Tunable Spectra for Multiplexed Optoacoustic and Fluorescence Bioimaging.

J-aggregation brings intriguing optical and electronic properties to molecular dyes and significantly expands their applicability across diverse domains, yet the challenge for rationally designing J-aggregating dyes persists. Herein, we developed a large number of J-aggregating dyes from scratch by progressively refining structure of a common heptamethine cyanine. J-aggregates with sharp spectral bands (full-width at half-maximum≤38 nm) are attained by introducing a branched structure featuring a benzyl and a trifluoroacetyl group at meso-position of dyes. Fine-tuning the benzyl group enables spectral regulation of J-aggregates. Analysis of single crystal data of nine dyes reveals a correlation between J-aggregation propensity and molecular arrangement within crystals. Some J-aggregates are successfully implemented in multiplexed optoacoustic and fluorescence imaging in animals. Notably, three-color multispectral optoacoustic tomography imaging with high spatiotemporal resolution is achieved, owing to the sharp and distinct absorption bands of the J-aggregates.

Structurally Modulated Formation of Cyanine J‐Aggregates with Sharp and Tunable Spectra for Multiplexed Optoacoustic and Fluorescence Bioimaging

AbstractJ‐aggregation brings intriguing optical and electronic properties to molecular dyes and significantly expands their applicability across diverse domains, yet the challenge for rationally designing J‐aggregating dyes persists. Herein, we developed a large number of J‐aggregating dyes from scratch by progressively refining structure of a common heptamethine cyanine. J‐aggregates with sharp spectral bands (full‐width at half‐maximum≤38 nm) are attained by introducing a branched structure featuring a benzyl and a trifluoroacetyl group at meso‐position of dyes. Fine‐tuning the benzyl group enables spectral regulation of J‐aggregates. Analysis of single crystal data of nine dyes reveals a correlation between J‐aggregation propensity and molecular arrangement within crystals. Some J‐aggregates are successfully implemented in multiplexed optoacoustic and fluorescence imaging in animals. Notably, three‐color multispectral optoacoustic tomography imaging with high spatiotemporal resolution is achieved, owing to the sharp and distinct absorption bands of the J‐aggregates.

Nature Products Chlorophyll Derivatives for NIR-II Fluorescence Bioimaging and Plant-Imaging.

The second near-infrared window (NIR-II, 1000-1700 nm) fluorescence imaging has attracted significant attention in research fields because of its unique advantages compared with conventional optical windows (400-900 nm). A variety of NIR-II fluorophores have been actively studied because they serve as a key component of fluorescence imaging. Among them, organic small molecule NIR-II fluorophores display outstanding imaging performance and many advantages, but types of small molecule NIR-II fluorophores with high biocompatibility are still quite limited. Novel molecular scaffolds based NIR-II dyes are highly desired. Herein, we hypothesized that chlorophyll is a new promising molecular platform for discovery NIR-II fluorophores. Thus, seven derivatives of derivatives were selected to characterize their optical properties. Interestingly, six chlorophyll derivatives displayed NIR-II fluorescence imaging capability. This characteristic allowed the successful NIR-II imaging of green leaves of various plants. Furthermore, most of these fluorophores showed capacity to monitor viscosity change because of their sensitive for viscosity. For demonstration of its biomedical applications, these probes were successfully used for NIR-II fluorescence-guided surgical resection of lymph nodes. In summary, chlorophylls are novel valuable tool molecules for NIR-II fluorescence imaging and have potential to expand their applications in biomedical field and plant science.

Self-assembled multicolor fluorescent nanoparticles derived from dopamine analogues: A versatile platform for biomedical applications

Fluorescent polydopamine (PDA) nanoparticles (FPNPs) have gained recognition as invaluable resources for a wide range of biomedical applications. Typically, these FPNPs are synthesized solely from dopamine (DA). In this study, our focus lies in the design of PDA-based multicolor fluorescent nanoparticles (m-FNPs) utilizing DA and its analogues, including levodopa (LVD), norepinephrine (NPP), 6-hydroxydopamine (HDA), and epinephrine (EPP) monomers, thereby paving the way for the next generation of FPNPs. The m-FNPs, respectively labeled as L-FNPs, N-FNPs, H-FNPs, E-FNPs, and D-FNPs, exhibit distinct band gaps influenced by the monomer’s structure, allowing versatile multicolor fluorescence bioimaging across a broad fluorescence emission spectrum ranging from 410 to 680 nm. Significantly, the catechol groups present on the surfaces of m-FNPs enable chelation with various theranostic metal ions and subsequent release under endo/lysosome pH conditions in cancer cells, thereby eliciting a cancer-specific “OFF-ON” fluorescence signal in vivo. Furthermore, integrating m-FNPs into poly(dimethylsiloxane) (PDMS) produces a tissue-adhesive fluorescence sheet that permits fluorescence monitoring of internal tissue surfaces within living organisms for 15 days. These m-FNPs-incorporated PDMS (m-FNPs-PDMS) sheets, enriched with catechol, carboxyl, and amine groups on their surfaces, exhibit significantly enhanced adhesion to biological tissues compared to conventional PDMS sheets containing PDA. Our findings suggest that m-FNPs pave the way for advancing PDA-based fluorescent nanoparticles with diverse applications in the biomedical field, supported by comprehensive in vitro and in vivo evaluations.

Bioinspired AIE Nanomedicine: A Burgeoning Technology for Fluorescence Bioimaging and Phototheranostics.

Nanomedicine on the basis of aggregated-induced emission (AIE) luminogens with exceptional potency is growing into a sparkling frontier in fluorescence imaging and phototheranostics. Of particular interest is biomimetic AIE nanomedicine comprised by AIE luminogens and biocarrier, which represents a win-win integration and are recently developed at a tremendous pace, mainly benefiting from the intrinsic advantages including enhanced biocompatibility, prolonged circulation time, specific targeting ability, immune activation, and supremely extraordinary phototheranostic outputs. In view of the inexhaustible and vigorous vitality in the field, this review provides an integrated picture on biomimetic AIE nanomedicine involving the basic concepts, significant breakthroughs, and recent trends. In addition, based on the current achievements, some critical challenges and perspectives are also discussed.

The influence of various polymer coatings on the in vitro and in vivo properties of PLGA nanoparticles: Comprehensive study

Nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) with various surface chemistry are widely used in biomedicine for theranostic applications. The nature of the external coating of nanoparticles has a significant influence on their efficiency as drug carriers or visualization agents. However, information about the mechanisms of nanoparticle accumulation in tumors and the influence of their surface properties on biodistribution is scarce due to the lack of systematic evaluation. Here we investigate the effect of different polymer coatings of the surface on in vitro and in vivo properties of PLGA nanoparticles. Namely, cell binding efficiency, cytotoxicity, efficiency of fluorescent bioimaging, and tumor accumulation were tested. The highest binding efficiency in vitro and cytotoxicity were observed for positively charged polymers. Interestingly, in vivo fluorescent visualization of tumor-bearing mice and quantitative measurements of biodistribution of magnetite-loaded nanoparticles indicated different dependences of accumulation in tumors on the coating of PLGA nanoparticles. This means that nanoparticle surface properties can simultaneously enhance imaging efficiency and decrease quantitative accumulation in tumors. The obtained data demonstrate the complexity of the dependence of nanoparticles’ effectiveness for theranostic applications on surface features. We believe that this study will contribute to the rational design of nanoparticles for effective cancer diagnostics and therapy.