Specific detection and simultaneously localized photothermal treatment of cancer cells using layer-by-layer assembled multifunctional nanoparticles

Recent advances in rare earth ion-doped upconversion nanomaterials: From design to their applications in food safety analysis

The misuse of chemicals in agricultural systems and food production leads to an increase in contaminants in food, which ultimately has adverse effects on human health. This situation has prompted a demand for sophisticated detection technologies with rapid and sensitive features, as concerns over food safety and quality have grown around the globe. The rare earth ion-doped upconversion nanoparticle (UCNP)-based sensor has emerged as an innovative and promising approach for detecting and analyzing food contaminants due to its superior photophysical properties, including low autofluorescence background, deep penetration of light, low toxicity, and minimal photodamage to the biological samples. The aim of this review was to discuss an outline of the applications of UCNPs to detect contaminants in food matrices, with particular attention on the determination of heavy metals, pesticides, pathogenic bacteria, mycotoxins, and antibiotics. The review briefly discusses the mechanism of upconversion (UC) luminescence, the synthesis, modification, functionality of UCNPs, as well as the detection principles for the design of UC biosensors. Furthermore, because current UCNP research on food safety detection is still at an early stage, this review identifies several bottlenecks that must be overcome in UCNPs and discusses the future prospects for its application in the field of food analysis.

Fluorescent-Nanoparticle-Impregnated Nanocomposite Polymeric Gels for Biosensing and Drug Delivery Applications

Nanocomposite polymeric gels infused with fluorescent nanoparticles have surfaced as a propitious category of substances for biomedical purposes owing to their exceptional characteristics. The aforementioned materials possess a blend of desirable characteristics, including biocompatibility, biodegradability, drug encapsulation, controlled release capabilities, and optical properties that are conducive to imaging and tracking. This paper presents a comprehensive analysis of the synthesis and characterization of fluorescent-nanoparticle-impregnated nanocomposite polymeric gels, as well as their biomedical applications, such as drug delivery, imaging, and tissue engineering. In this discourse, we deliberate upon the merits and obstacles linked to these substances, encompassing biocompatibility, drug encapsulation, optical characteristics, and scalability. The present study aims to provide an overall evaluation of the potential of fluorescent-nanoparticle-impregnated nanocomposite polymeric gels for biomedical applications. Additionally, emerging trends and future directions for research in this area are highlighted.

ICG-Dimeric Her2-Specific Affibody Conjugates for Tumor Imaging and Photothermal Therapy for Her2-Positive Tumors

Human epidermal growth factor receptor 2 (Her2) is abundantly expressed in various solid tumors. The Her2-specific Affibody (Z_Her2:2891) has been clinically tested in patients with Her2-positive breast cancer and is regarded as an ideal drug carrier for tumor diagnosis and targeted treatment. Indocyanine green (ICG) can be used as a photosensitizer for photothermal therapy (PTT), in addition to fluorescent dyes for tumor imaging. In this study, a dimeric Her2-specific Affibody (Z_Her2) based on Z_Her2:2891 was prepared using the E. coli expression system and then coupled to ICG through an N-hydroxysuccinimide (NHS) ester reactive group to construct a novel bifunctional protein drug (named ICG-Z_Her2) for tumor diagnosis and PTT. In vitro, ICG-Z_Her2-mediated PTT selectively and efficiently killed Her2-positive BT-474 and SKOV-3 tumor cells rather than Her2-negative HeLa tumor cells. In vivo, ICG-Z_Her2 specifically accumulated in Her2-positive SKOV-3 tumor grafts rather than Her2-negative HeLa tumor grafts; high-contrast tumor optical images were obtained. However, Her2-negative HeLa tumor grafts were not detected. More importantly, ICG-Z_Her2-mediated PTT exhibited a significantly enhanced antitumor effect in mice bearing SKOV-3 tumor grafts owing to the good photothermal properties of ICG-Z_Her2. Of note, ICG-Z_Her2 did not exhibit acute toxicity in mice during short-term treatment. Overall, our findings indicate that ICG-Z_Her2 is a promising bifunctional drug for Her2-positive tumor diagnosis and PTT.

Nanotechnology: A Promising Approach for Cancer Diagnosis, Therapeutics and Theragnosis

Cancer remains the most devastating disease and the major cause of mortality worldwide. Although early diagnosis and treatment are the key approach in fighting against cancer, the available conventional diagnostic and therapeutic methods are not efficient. Besides, ineffective cancer cell selectivity and toxicity of traditional chemotherapy remain the most significant challenge. These limitations entail the need for the development of both safe and effective cancer diagnosis and treatment options. Due to its robust application, nanotechnology could be a promising method for in-vivo imaging and detection of cancer cells and cancer biomarkers. Nanotechnology could provide a quick, safe, cost-effective, and efficient method for cancer management. It also provides simultaneous diagnosis and treatment of cancer using nano-theragnostic particles that facilitate early detection and selective destruction of cancer cells. Updated and recent discussions are important for selecting the best cancer diagnosis, treatment, and management options, and new insights on designing effective protocols are utmost important. This review discusses the application of nanotechnology in cancer diagnosis, therapeutics, and theragnosis and provides future perspectives in the field.

Recent Advances of Upconversion Nanomaterials in the Biological Field

Rare Earth Upconversion nanoparticles (UCNPs) are a type of material that emits high-energy photons by absorbing two or more low-energy photons caused by the anti-stokes process. It can emit ultraviolet (UV) visible light or near-infrared (NIR) luminescence upon NIR light excitation. Due to its excellent physical and chemical properties, including exceptional optical stability, narrow emission band, enormous Anti-Stokes spectral shift, high light penetration in biological tissues, long luminescent lifetime, and a high signal-to-noise ratio, it shows a prodigious application potential for bio-imaging and photodynamic therapy. This paper will briefly introduce the physical mechanism of upconversion luminescence (UCL) and focus on their research progress and achievements in bio-imaging, bio-detection, and photodynamic therapy.

Sample preparation considerations for surface and crystalline properties and ecotoxicity of bare and silica-coated magnetite nanoparticles

Magnetite (Fe₃O₄) nanoparticles (NPs) have widely used in various fields, including in medicine, due to their (super)paramagnetic properties. This requires a thorough evaluation of their possible hazardous effects. However, there is no standard procedure for the preparation of oxidation-prone NPs (such as magnetite) before subjecting them to biological assays. In this study we used Fe₃O₄ NPs (bare and silica-coated) as test samples to compare different preparation methods (ultrasound, centrifugation and filteration of NPs suspensions) based on X-ray and dynamic light scattering analysis and evaluation of microstructure and surface charge. After oxidation and functionalization, all samples retained their superparamagnetic behaviour. The toxicity of NP suspensions obtained by the methods described for Paramecium caudatum ciliates and Sinapis alba plants was evaluated.

The charge and surface reactivity of magnetite nanoparticles can be affected by the different separation methods leading to their toxicity changes.

Recent advances in nanoscale materials for antibody-based cancer theranostics

The quest for advanced management tools or options of various cancers has been on the rise to efficiently reduce their risks of mortality without the demerits of conventional treatments (e.g., undesirable side effects of the medications on non-target tissues, non-targeted distribution, slow clearance of the administered drugs, and the development of drug resistance over the duration of therapy). In this context, nanomaterials-antibody conjugates can offer numerous advantages in the development of cancer theranostics over conventional delivery systems (e.g., highly specific and enhanced biodistribution of the drug in targeted tissues, prolonged systemic circulation, low toxicity, and minimally invasive molecular imaging). This review comprehensively discusses and evaluates recent advances in the application of nanomaterial-antibody bioconjugates for cancer theranostics for the further advancement in the control of diverse cancerous diseases. Further, discussion is expanded to cover the various challenges and limitations associated with the design and development of nanomaterial-antibody conjugates applicable towards better management of cancer.

Preparation, surface functionalization and application of Fe3O4 magnetic nanoparticles

This paper reviews recent developments in the preparation, surface functionalization, and applications of Fe₃O₄ magnetic nanoparticles. Especially, it includes preparation methods (such as electrodeposition, polyol methods, etc.), organic materials (such as polymers, small molecules, surfactants, biomolecules, etc.) or inorganic materials (such as silica, metals, and metal oxidation/sulfide, functionalized coating of carbon surface, graphene, etc.) and its applications (such as magnetic separation, protein fixation, magnetic catalyst, environmental treatment, medical research, etc.). In the end, some existing challenges and possible future trends in the field were discussed.

Nanotechnology in cancer diagnosis: progress, challenges and opportunities

In the fight against cancer, early detection is a key factor for successful treatment. However, the detection of cancer in the early stage has been hindered by the intrinsic limits of conventional cancer diagnostic methods. Nanotechnology provides high sensitivity, specificity, and multiplexed measurement capacity and has therefore been investigated for the detection of extracellular cancer biomarkers and cancer cells, as well as for in vivo imaging. This review summarizes the latest developments in nanotechnology applications for cancer diagnosis. In addition, the challenges in the translation of nanotechnology-based diagnostic methods into clinical applications are discussed.

NIR triggered glycosylated gold nanoshell as a photothermal agent on melanoma cancer cells

Nowadays, gold nanoshells are used in targeted nano photothermal cancer therapy. This study surveyed the application of gold nanoshell (GNs) to thermal ablative therapy for melanoma cancer cells and it takes advantage of the near infrared absorption of gold nanoshells. The synthesis and characterization of glycosylated gold nanoshells (GGNs) were done. The cytotoxicity and photothermal effects of GNs on melanoma cells were evaluated using MTT assay and flow cytometry. The characterization data showed that GGNs are spherical, with a hydrodynamic size of 46.7 nm. Results suggest that the cellular uptake of GGNs was about 78%. Viability assays showed no significant toxicity at low concentrations of GNs. The higher heating rate and toxicity of cancer cells were obtained for the cells exposed to 808 nm NIR laser after incubation with GGNs rather than the GNs. The viability of these cells has dramatically decreased by 29%. Furthermore, 61% more cell lethality was achieved for A375 cells using combined photothermal therapy and treatment with GGNs in comparison to NIR radiation alone. In conclusion, our findings suggest that the synthesized gold/silica core-shell nanoparticles conjugated with glucosamine have high potentials to be considered as an efficient metal-nanoshell in the process of targeted cancer photothermal therapy.

Polymer coated gold-ferric oxide superparamagnetic nanoparticles for theranostic applications

BACKGROUND

Engineered inorganic nanoparticles (NPs) are essential components in the development of nanotechnologies. For applications in nanomedicine, particles need to be functionalized to ensure a good dispersibility in biological fluids. In many cases however, functionalization is not sufficient: the particles become either coated by a corona of serum proteins or precipitate out of the solvent. We show that by changing the coating of magnetic iron oxide NPs using poly-L-lysine (PLL) polymer the colloidal stability of the dispersion is improved in aqueous solutions including water, phosphate buffered saline (PBS), PBS with 10% fetal bovine serum (FBS) and cell culture medium, and the internalization of the NPs toward living mammalian cells is profoundly affected.

METHODS

A multifunctional magnetic NP is designed to perform a near-infrared (NIR)-responsive remote control photothermal ablation for the treatment of breast cancer. In contrast to the previously reported studies of gold (Au) magnetic (Fe3O4) core-shell NPs, a Janus-like nanostructure is synthesized with Fe3O4 NPs decorated with Au resulting in an approximate size of 60 nm mean diameter. The surface of trisoctahedral Au-Fe3O4 NPs was coated with a positively charged polymer, PLL to deliver the NPs inside cells. The PLL-Au-Fe3O4 NPs were characterized by transmission electron microscopy (TEM), XRD, FT-IR and dynamic light scattering (DLS). The unique properties of both Au surface plasmon resonance and superparamagnetic moment result in a multimodal platform for use as a nanothermal ablator and also as a magnetic resonance imaging (MRI) contrast agent, respectively. Taking advantage of the photothermal therapy, PLL-Au-Fe3O4 NPs were incubated with BT-474 and MDA-MB-231 breast cancer cells, investigated for the cytotoxicity and intracellular uptake, and remotely triggered by a NIR laser of ~ 808 nm (1 W/cm2 for 10 min).

RESULTS

The PLL coating increased the colloidal stability and robustness of Au-Fe3O4 NPs (PLL-Au-Fe3O4) in biological media including cell culture medium, PBS and PBS with 10% fetal bovine serum. It is revealed that no significant (< 10%) cytotoxicity was induced by PLL-Au-Fe3O4 NPs itself in BT-474 and MDA-MB-231 cells at concentrations up to 100 μg/ml. Brightfield microscopy, fluorescence microscopy and TEM showed significant uptake of PLL-Au-Fe3O4 NPs by BT-474 and MDA-MB-231 cells. The cells exhibited 40 and 60% inhibition in BT-474 and MDA-MB-231 cell growth, respectively following the internalized NPs were triggered by a photothermal laser using 100 μg/ml PLL-Au-Fe3O4 NPs. The control cells treated with NPs but without laser showed < 10% cell death compared to no laser treatment control CONCLUSION: Combined together, the results demonstrate a new polymer gold superparamagnetic nanostructure that integrates both diagnostics function and photothermal ablation of tumors into a single multimodal nanoplatform exhibiting a significant cancer cell death.

Sensitive Detection of MMP9 Enzymatic Activities in Single Cell-Encapsulated Microdroplets as an Assay of Cancer Cell Invasiveness

Matrix metalloproteinases (MMPs) are typically up-regulated in cancer cells, and play a critical role in assisting metastasis by the breakdown of the extracellular matrix. Here we report an effective strategy for cell invasiveness assay by integrating MMP9 functional activity analysis with single cell-encapsulated microdroplets. A flow focusing capillary microfluidic device has been assembled using "off-the-shelf" fluidic components for high-throughput generation of microdroplets. Tumor cells, MMP9 specific peptides, and other cofactors can be loaded into the device and encapsulated into individual droplets as dynamic microreactors for proteolytic cleavage of the substrate. This design allows for rapid and robust detection of MMP9 enzymatic activities by fluorescent signals in a few minutes. It represents the first demonstration of quantifying MMP9 enzymatic activities at the single cell level with a high throughput performance. This new technique promises functional evaluation of cancer cell invasiveness for important diagnostic or prognostic applications.

Lignin-AuNPs liquid marble for remotely-controllable detection of Pb2

This work reported the green and facile fabrication of a versatile lignin-AuNP composite, which was readily and remotely encapsulated to form novel liquid marbles. The marbles can stay suspended in water, and show excellent photothermal conversion properties, as well as visual detection and adsorption towards Pb²⁺. More importantly, the marbles can simultaneously remotely detect and adsorb Pb²⁺ via co-precipitation by simply controlling the near infrared (NIR) irradiation. It is believed that the remotely-controllable NIR-responsive lignin-AuNPs liquid marble can be used in Pb²⁺-related reactions. The liquid marble can be placed in the system at the very beginning of the reaction and stably stays on the surface until the reaction has ended. After reacting, upon remote NIR irradiation, the liquid marble bursts to adsorb Pb²⁺, and the residual Pb²⁺ can be collected. This facile manipulation strategy does not use complicated nanostructures or sophisticated equipment, so it has potential applications for channel-free microfluidics, smart microreactors, microengines, and so on.

Hybrid polymeric nano-capsules loaded with gold nanoclusters and indocyanine green for dual-modal imaging and photothermal therapy

Currently there is a great need to design nano-carriers which enable multi-modal imaging of tumors and administration of therapeutics with high efficacy simultaneously. Herein we report a facile and robust approach to fabricate multifunctional nano-capsules based on double emulsions. The hybrid nano-capsules were loaded with BSA capped gold nanoclusters (AuNCs) and indocyanine green (ICG) for dual-modal imaging and effective photothermal therapy. RGD peptides were conjugated onto the surface of the hybrid nano-capsules to target cells overexpressing integrin α_νβ₃. We demonstrated that the as-prepared nano-capsules can be used for both one-photon and two-photon fluorescence imaging of tumor cells, and subsequent photothermal ablation with high effectiveness. The background noise of tissue autofluorescence was dramatically suppressed in the two-photon imaging mode. Therefore, it assisted a great deal to acquire images with a high signal-to-noise ratio using the hybrid nano-capsules. Due to a unique combination of the one-photon/two-photon fluorescence imaging and highly-effective photothermal properties, the hybrid nano-capsules may find broad biomedical applications as attractive theranostic nanomaterials.

Upconversion nanocomposites for photo-based cancer theranostics

Upconversion nanoparticles (UCNPs) are able to convert long wavelength excitation light into high energy ultraviolet (UV) or visible emissions, and they have attracted significant attention because of their distinct photochemical properties including sharp emission bands, low autofluorescence, high tissue penetration depth and minimal photodamage to tissues.

Plasmon-induced hyperthermia: hybrid upconversion NaYF4:Yb/Er and gold nanomaterials for oral cancer photothermal therapy

Nanocomposites consisting of upconversion nanoparticles (UCPs) and plasmonic materials have been widely explored for bio-imaging and cancer photothermal therapy (PTT). However, several challenges, including incomprehensible efficiency of energy transfer processes and optimization of the conditions for plasmon-induced photothermal effects, still exist. In this study, we fabricated NaYF₄:Yb³⁺/Er³⁺ nanoparticles (NPs) conjugated with gold nanomaterials (Au NMs), such as Au NPs and gold nanorods (Au NRs). NaYF₄:Yb³⁺/Er³⁺ NPs were used as photoconverters, which could emit green and red light under excitation of a 980 nm laser; Au NPs and Au NRs were also prepared and used as heat producers. The silica shell was further coated around UCPs to improve biocompatibility and as a bridge linking UCPs and the Au NMs. Most importantly, the thickness of the silica shell was tuned precisely to investigate the effective distance of the plasmonic field for heat induction. Energy transfer was confirmed by the declining UCL photoluminescence and emission decay time after connecting to the Au NMs. Moreover, a simulative model was built using the finite element method to assess the differences in heat generation between UCP@SiO₂-NPs and UCP@SiO₂-NRs. The surfaces of the hybrid nanocomposites were modified with folic acid to improve the specific targeting to cancer cells. The performance of the modified hybrid nanocomposites in PTT for OECM-1 oral cancer cells was evaluated.

Mitophagy induced by nanoparticle-peptide conjugates enabling an alternative intracellular trafficking route

The intracellular behaviors of nanoparticles are fundamentally important for the evaluation of their biosafety and the designs of nano carrier-assisted drug delivery with high therapeutic efficacy. It is still in a great need to discover how functionalized nanoparticles are transported inside the cells, for instance, in a complicated fashion of translocation between different types of cell organelles. Here we report a new understanding of the interactions between nanoparticles and cells by the development of polyoxometalates nanoparticle-peptide conjugates and investigation of their intracellular trafficking behaviors. The as-prepared nanoparticles are featured with a unique combination of fluorescence and high contrast for synchrotron X-ray-based imaging. Functional surface modification with peptides facilitates effective delivery of the nanoparticles onto the target organelle (mitochondria) and subsequent intracellular trafficking in a dynamic mode. Interestingly, our experimental results have revealed that autophagy of mitochondria (mitophagy) can be induced by NP-peptide as a cellular response for recycling the damaged organelles, through molecular mediation associated with the change of mitochondrial membrane potential. The biological effects induced by NP-peptide reciprocally affect the distribution patterns and fates of nanoparticles in the cell metabolism by providing an alternative route of intracellular trafficking. The new understanding of the mutual activities between nanoparticles and cells will enrich our approaches in the development of nanobiotechnology and nano-medicine for disease treatments.

A multi-functional fluorescent scaffold as a multi-colour probe: design and application in targeted cell imaging

A new scaffold material based on a novel targeting strategy has been developed, benefiting from recent progress in the development of tailor-made fluorescent bioprobes for cellular imaging and opening a new viewpoint for further improvements in in vitro and in vivo imaging.

Polypeptide-functionalized NaYF4:Yb(3+),Er(3+) nanoparticles: red-emission biomarkers for high quality bioimaging using a 915 nm laser

We prepared poly-L-aspartic acid (PASP) functionalized NaYF4:Yb(3+),Er(3+) upconversion nanoparticles (UCNP-PASP). These nanoparticles can give red upconversion emission under excitation at 915 nm, whose wavelength of emission and excitation is located in the optical window of biological tissue. Dynamic laser scatting and zeta potentials of UCNP-PASP were used to study their stabilities in different aqueous solution. To understand the mechanism of the red emission of UCNP-PASP, photoluminescence spectra of samples were recorded before and after modification with PASP, poly acrylic acid (PAA), and poly(ether imide) (PEI) ligands under excitation at 915 and 980 nm, respectively. The cytotoxicity of the UCNP-PASP was also examined on a A549 cell and KB cell by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. Moreover, the PASP-functionalized UCNP was employed as a potential biomarker for in vitro and in vivo experiments of upconversion luminescence imaging.