Mesoporous silica-coated upconversion nanocrystals for near infrared light-triggered control of gene expression in zebrafish

Recent advances in functionalized upconversion nanoparticles for light-activated tumor therapy

Upconversion nanoparticles (UCNPs) are a class of optical nanocrystals doped with lanthanide ions that offer great promise for applications in controllable tumor therapy. In recent years, UCNPs have become an important tool for studying the treatment of various malignant and nonmalignant cutaneous diseases. UCNPs convert near-infrared (NIR) radiation into shorter-wavelength visible and ultraviolet (UV) radiation, which is much better than conventional UV activated tumor therapy as strong UV-light can be damaging to healthy surrounding tissue. Moreover, UV light generally does not penetrate deeply into the skin, an issue that UCNPs can now address. However, the current studies are still in the early stage of research, with a long way to go before clinical implementation. In this paper, we systematically analysed recent advances in light-activated tumor therapy using functionalized UCNPs. We summarized the purpose and mechanism of UCNP-based photodynamic therapy (PDT), gene therapy, immunotherapy, chemo-therapy and integrated therapy. We believe the creation of functional materials based on UCNPs will offer superior performance and enable innovative applications, increasing the scope and opportunities for cancer therapy in the future.

Visible-Light-Mediated Modification and Manipulation of Biomacromolecules

Chemically modified biomacromolecules-i.e., proteins, nucleic acids, glycans, and lipids-have become crucial tools in chemical biology. They are extensively used not only to elucidate cellular processes but also in industrial applications, particularly in the context of biopharmaceuticals. In order to enable maximum scope for optimization, it is pivotal to have a diverse array of biomacromolecule modification methods at one's disposal. Chemistry has driven many significant advances in this area, and especially recently, numerous novel visible-light-induced photochemical approaches have emerged. In these reactions, light serves as an external source of energy, enabling access to highly reactive intermediates under exceedingly mild conditions and with exquisite spatiotemporal control. While UV-induced transformations on biomacromolecules date back decades, visible light has the unmistakable advantage of being considerably more biocompatible, and a spectrum of visible-light-driven methods is now available, chiefly for proteins and nucleic acids. This review will discuss modifications of native functional groups (FGs), including functionalization, labeling, and cross-linking techniques as well as the utility of oxidative degradation mediated by photochemically generated reactive oxygen species. Furthermore, transformations at non-native, bioorthogonal FGs on biomacromolecules will be addressed, including photoclick chemistry and DNA-encoded library synthesis as well as methods that allow manipulation of the activity of a biomacromolecule.

Genetic Manipulation of the Equine Oocyte and Embryo

As standard in vitro fertilization is not a viable technique in horses yet, many different techniques have been used to create equine embryos for research purposes. One such method is parthenogenesis in which an oocyte is induced to mature into an embryo-like state without the introduction of a spermatozoon, and thus they are not considered true embryos. Another method is somatic cell nuclear transfer (SCNT), in which a somatic cell nucleus from an extant horse is inserted into an enucleated oocyte, creating a genetic clone of the donor horse. Due to limited availability of equine oocytes in the United States, researchers have investigated the potential for combining equine somatic cell nuclei with oocytes from other species to make embryos for research purposes, which has not been successful to date. There has also been a rising interest in producing transgenic animals using sperm exposed to exogenous DNA. The successful creation of transgenic equine blastocysts shows the promise of sperm mediated gene transfer (SMGT), but this method is not ideal for other applications, like gene therapy, because it cannot be used to induce targeted mutations. That is why technologies like CRISPR/Cas9 are vital. In this review, we argue that parthenogenesis, SCNT, and interspecies SCNT can be considered genetic manipulation strategies as they create embryos that are genetically identical to their parent cell. Here, we describe how these methods are performed and their applications and we also describe the few methods that have been used to directly modify equine embryos: SMGT and CRISPR/Cas9.

Nanomaterials meet zebrafish: Toxicity evaluation and drug delivery applications

With the rapid development of engineered nanomaterials for various applications, in vivo toxicological studies for evaluating the potential hazardous effects of nanomaterials on environmental and human safety are in urgent need. Zebrafish has long been considered as the "gold standard" for biosafety assessments of chemicals and pollutants due to its high fecundity, cost-effectiveness, well-characterized developmental stages, optical transparency, and so forth. Thus, zebrafish holds great potential for high-throughput nanotoxicity screening. In this review, we summarize the in vivo toxicological profiles of different nanomaterials, including Ag nanoparticles (NPs), CuO NPs, silica NPs, polymeric NPs, quantum dots, nanoscale metal-organic frameworks, etc, in zebrafish and focus on how the physicochemical properties (e.g., size, surface charge, and surface chemistry) of these nanomaterials influence their biosafety. In addition, we also report the recent advances of the in vivo delivery of nanopharmaceuticals using zebrafish as the model organism for therapeutic assessment, biodistribution tracking, and the controlled release of loaded drugs. Limitations and special considerations of zebrafish model are also discussed. Overall, zebrafish is expected to serve as a high-throughput screening platform for nanotoxicity and drug delivery assessment, which may instruct the design of safe nanomaterials and more effective nanomedicines.

Nanotransducers for Near-Infrared Photoregulation in Biomedicine

Photoregulation, which utilizes light to remotely control biological events, provides a precise way to decipher biology and innovate in medicine; however, its potential is limited by the shallow tissue penetration and/or phototoxicity of ultraviolet (UV)/visible light that are required to match the optical responses of endogenous photosensitive substances. Thereby, biologically friendly near-infrared (NIR) light with improved tissue penetration is desired for photoregulation. Since there are a few endogenous biomolecules absorbing or emitting light in the NIR region, the development of molecular transducers is essential to convert NIR light into the cues for regulation of biological events. In this regard, optical nanomaterials able to convert NIR light into UV/visible light, heat, or free radicals are suitable for this task. Here, the recent developments of optical nanotransducers for NIR-light-mediated photoregulation in medicine are summarized. The emerging applications, including photoregulation of neural activity, gene expression, and visual systems, as well as photochemical tissue bonding, are highlighted, along with the design principles of nanotransducers. Moreover, the current challenges and perspectives in this field are discussed.

Let's get small (and smaller): Combining zebrafish and nanomedicine to advance neuroregenerative therapeutics

Several key attributes of zebrafish make them an ideal model system for the discovery and development of regeneration promoting therapeutics; most notably their robust capacity for self-repair which extends to the central nervous system. Further, by enabling large-scale drug discovery directly in living vertebrate disease models, zebrafish circumvent critical bottlenecks which have driven drug development costs up. This review summarizes currently available zebrafish phenotypic screening platforms, HTS-ready neurodegenerative disease modeling strategies, zebrafish small molecule screens which have succeeded in identifying regeneration promoting compounds and explores how intravital imaging in zebrafish can facilitate comprehensive analysis of nanocarrier biodistribution and pharmacokinetics. Finally, we discuss the benefits and challenges attending the combination of zebrafish and nanoparticle-based drug optimization, highlighting inspiring proof-of-concept studies and looking toward implementation across the drug development community.

Amine-functionalized, porous silica-coated NaYF4:Yb/Er upconversion nanophosphors for efficient delivery of doxorubicin and curcumin

Upconversion nanoparticles (UCNP) with unique multi-photon excitation photo-luminescence properties have been extensively explored as novel contrast agents for low-background biomedical imaging. There is an increasing interest in employing UCNPs as carrier for drug delivery as these offers a unique opportunity to combine therapy and diagnostics in one platform (theranostics). In the present work, we report microwave-assisted synthesis of hexagonal NaYF₄:Yb/Er UCNPs coated with porous silica and functionalized with amine (UCNP@mSiO₂). The UCNP@mSiO₂ were investigated for controlled delivery of a chemotherapeutic agent, doxorubicin (DOX, hydrophilic), and a chemosensitizing agent, curcumin (CCM, hydrophobic). The drug loading was relatively higher for DOX (17.4%), in comparison to CCM (8.1%). The cumulative drug release from DOX-loaded UCNP@mSiO₂ were 30 and 41% at physiological (7.4) and tumoral (6.4) pH, following a pseudo Fickian release pattern, whereas the release from CCM-loaded UCNP@mSiO₂ were 27 and 50% at pH 7.4 and 6.4, following a non-Fickian and pseudo-Fickian release patterns, respectively. Both DOX and CCM-loaded UCNP@mSiO₂ exhibited pH-dependent controlled drug delivery but the effect was more pronounced for CCM, the hydrophobic chemosensitizer. Cell viability assay using HeLa cells showed that DOX-loaded UCNP@mSiO₂ inhibit cell growth in a dose-dependent manner, similar to free DOX, but the cell inhibition activity of free CCM was lower than CCM passively entrapped in UCNP@mSiO₂. Confocal microscopy studies revealed cell uptake of both the drug by HeLa cells. Thus, UCNP@mSiO₂ exhibited the unique capability to deliver hydrophilic and hydrophobic drugs, individually. UCNP@mSiO₂ carrier, equipped with theranostic capabilities, may potentially be used for pH-responsive release of chemotherapeutic agents in cancer environment.

Lanthanide Doped Near Infrared Active Upconversion Nanophosphors: Fundamental Concepts, Synthesis Strategies, and Technological Applications

Near infrared (NIR) light utilization in a range of current technologies has gained huge significance due to its abundance in nature and nondestructive properties. NIR active lanthanide (Ln) doped upconversion nanomaterials synthesized in controlled shape, size, and surface functionality can be combined with various pertinent materials for extensive applications in diverse fields. Upconversion nanophosphors (UCNP) possess unique abilities, such as deep tissue penetration, enhanced photostability, low toxicity, sharp emission peaks, long anti-Stokes shift, etc., which have bestowed them with prodigious advantages over other conventional luminescent materials. As new generation fluorophores, UCNP have found a wide range of applications in various fields. In this Review, a comprehensive overview of lanthanide doped NIR active UCNP is provided by discussing the fundamental concepts including the different mechanisms proposed for explaining the upconversion processes, followed by the different strategies employed for the synthesis of these materials, and finally the technological applications of UCNP, mainly in the fields of bioimaging, drug delivery, sensing, and photocatalysis by highlighting the recent works in these areas. In addition, a brief note on the applications of UCNP in other fields is also provided along with the summary and future perspectives of these materials.

Recent Development of Inorganic Nanoparticles for Biomedical Imaging

Inorganic nanoparticle-based biomedical imaging probes have been studied extensively as a potential alternative to conventional molecular imaging probes. Not only can they provide better imaging performance but they can also offer greater versatility of multimodal, stimuli-responsive, and targeted imaging. However, inorganic nanoparticle-based probes are still far from practical use in clinics due to safety concerns and less-optimized efficiency. In this context, it would be valuable to look over the underlying issues. This outlook highlights the recent advances in the development of inorganic nanoparticle-based probes for MRI, CT, and anti-Stokes shift-based optical imaging. Various issues and possibilities regarding the construction of imaging probes are discussed, and future research directions are suggested.

Enhanced gene transfection efficiency by use of peptide vectors containing laminin receptor-targeting sequence YIGSR

This study presents the design and evaluation of a series of multifunctional peptides and their gene delivery abilities. The peptide sequences contained a cell-penetrating segment, six continuous histidine residues, a stearyl moiety and a laminin receptor-targeting segment. The YIGSR segment promoted cellular uptake through the interaction with laminin receptors on the surface of cells, which resulted in a great improvement in gene transfection efficiency. The conformation, particle size and zeta potential of peptide/DNA complexes were characterized via circular dichroism and dynamic light scattering. Their gene transfection efficiency was investigated by fluorescence-activated cell sorting and confocal microscopy. The transfection efficiency of the designed peptide vectors was higher than that of Lipo 2000. The peptide TAT-H₆-K(C₁₈)-YIGSR displayed transfection efficiencies at N/P ratios of 6, which was 3.5 and 7 times higher than that of Lipo 2000 in B16F10 and 293T cells, respectively. All peptides exhibited lower cytotoxicity than Lipo 2000 in B16F10 and 293T cells. In summary, the designed YIGSR-containing multifunctional peptide gene vectors promoted cellular uptake and gene transfection. Their in vivo transfection ability was investigated in zebrafish, and the transfection efficiency was determined by confocal microscopy and bioluminescence imaging. The peptide vectors, owing to their relatively short sequences and ease of functionalization, offer a promising approach for gene delivery because of their low cytotoxicity and high transfection efficiency.

Molecular design of upconversion nanoparticles for gene delivery

Due to their large anti-Stokes shifts, sharp emission spectra and long excited-state lifetimes, upconversion nanoparticles (UCNPs) have attracted an increasing amount of research interests, and have shown great potential for enhancing the practical utility of gene therapy, whose versatility has been limited by existing gene delivery technologies that are basically mono-functional in nature. Despite this, up to now in-depth analysis of the development of UCNPs for gene delivery has been scant in the literature, even though there has been an upsurge of reviews on the chemistry of UCNPs and their applications in bioimaging and drug delivery. To fill this gap, this review aims to present the latest advances in the development and applications of UCNPs as gene carriers. Prior to describing the prominent works published in the field, a critical view on the properties, chemistry and molecular design of UCNPs for gene delivery is provided. With a synopsis of the recent advances in UCNP-mediated gene delivery, challenges and opportunities could be illuminated for clinical translation of works in this nascent field of research.

Benzoyl Peroxide Detection in Real Samples and Zebrafish Imaging by a Designed Near-Infrared Fluorescent Probe

A novel near-infrared fluorescence off-on probe, (E)-3,3-dimethyl-1-propyl-2-(2-(6-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyloxy)-2,3-dihydro-1H-xanthen-4-yl)vinyl)-3H-indolium (1), is developed and applied to benzoyl peroxide (BPO) detection in real samples and fluorescence imaging in living cells and zebrafish. When arylboronate as the recognition unit is connected to a stable hemicyanine skeleton, the probe is readily prepared, which exhibits superior analytical performance, such as near-infrared fluorescence emission over 700 nm and high sensitivity with a low detection limit of 47 nM. Upon reaction with BPO, phenylboronic acid pinacol ester is oxidized, followed by hydrolysis and 1,4-elimination of o-quinone methide to release fluorophore. In addtion, the probe displays high selectivity toward BPO over other common substances, which makes it of great potential use in quantitative and simple detection of BPO in wheat flour and antimicrobial agent. More importantly, the probe has been successfully demonstrated for monitoring BPO in living HeLa cells and zebrafish. The probe with superior properties could be of great potential use in other biosystems and in vivo studies.

Analyses in zebrafish embryos reveal that nanotoxicity profiles are dependent on surface-functionalization controlled penetrance of biological membranes

Mesoporous silica nanoparticles (MSNs) are extensively explored as drug delivery systems, but in depth understanding of design-toxicity relationships is still scarce. We used zebrafish (Danio rerio) embryos to study toxicity profiles of differently surface functionalized MSNs. Embryos with the chorion membrane intact, or dechoroniated embryos, were incubated or microinjected with amino (NH₂-MSNs), polyethyleneimine (PEI-MSNs), succinic acid (SUCC-MSNs) or polyethyleneglycol (PEG-MSNs) functionalized MSNs. Toxicity was assessed by viability and cardiovascular function. NH₂-MSNs, SUCC-MSNs and PEG-MSNs were well tolerated, 50 µg/ml PEI-MSNs induced 100% lethality 48 hours post fertilization (hpf). Dechoroniated embryos were more sensitive and 10 µg/ml PEI-MSNs reduced viability to 5% at 96hpf. Sensitivity to PEG- and SUCC-, but not NH₂-MSNs, was also enhanced. Typically cardiovascular toxicity was evident prior to lethality. Confocal microscopy revealed that PEI-MSNs penetrated into the embryos whereas PEG-, NH2- and SUCC-MSNs remained aggregated on the skin surface. Direct exposure of inner organs by microinjecting NH₂-MSNs and PEI-MSNs demonstrated that the particles displayed similar toxicity indicating that functionalization affects the toxicity profile by influencing penetrance through biological barriers. The data emphasize the need for careful analyses of toxicity mechanisms in relevant models and constitute an important knowledge step towards the development of safer and sustainable nanotherapies