Polymerically engineered upconversion nanoparticles (UCNPs) as contrast agent for functionally modified optical coherence tomography (OCT)

Assessment of NIR-triggered PEG-coated NaGdF4:Tm3+/Yb3+bio-compatible upconversion nanoparticles for contrast enhancement in OCT imaging and optical thermometry

In this investigation, we embarked on the synthesis of polyethylene glycol coated NaGdF4:Tm3+/Yb3+upconversion nanoparticles (UCNPs), aiming to assess their utility in enhancing image contrast within the context of swept source optical coherence tomography (OCT) and photo-thermal OCT imaging. Our research unveiled the remarkable UC emissions stemming from the transitions of Tm3+ions, specifically the1G4→3H6transitions, yielding vibrant blue emissions at 472 nm. We delved further into the UC mechanism, meticulously scrutinizing decay times and the nanoparticles' capacity to convert radiation into heat. Notably, these nanoparticles exhibited an impressive photo-thermal conversion efficiency of 37.5%. Furthermore, our investigations into their bio-compatibility revealed a promising outcome, with more than 90% cell survival after 24 h of incubation with HeLa cells treated with UCNPs. The nanoparticles demonstrated a notable thermal sensitivity of 4.7 × 10-3K-1at 300 K, signifying their potential for precise temperature monitoring at the cellular level.

UCNPs-labeled electrospun scaffolds used to monitor in vivo degradation and bone tissue regeneration

Biodegradable electrospun bone repair materials are effective means to treat bone defects. However, because the electrospun substrates are mostly organic polymer materials, there is a lack of real-time and intuitive monitoring methods for their degradation in vivo. Therefore, it is of great significance to develop in vivo traced electrospun bone repair materials for postoperative observation of their degradation. In this research, polycaprolactone/up-conversion nanoparticles/magnesium oxide (PCL/UCNPs/MgO) composite scaffolds were prepared by electrospun based on the luminescence characteristics of up-conversion nanoparticles (UCNPs) under near infrared excitation and the osteogenic ability of MgO. The in vivo and in vitro degradation results showed that with the increase of time, the electrospun scaffolds gradually degraded and its luminescence intensity decreased. The addition of UCNPs can effectively monitor the degradation of the scaffolds. In addition, the prepared electrospun scaffolds had great biocompatibility, among which PCL-1%UCNPs-1%MgO (P1U1M) electrospun scaffolds had obvious effect on promoting osteogenic differentiation of mouse embryonic osteoblasts cells (MC3T3-E1) in vitro. In conclusion, P1U1M electrospun scaffolds have the potential to induce bone regeneration at bone defect sites, and can monitor the degradation of electrospun scaffolds. It may be a potential candidate material for bone regeneration in defect area.

NaYF4:Ho3+/Yb3+@NaGdF4 core@shell upconversion nanoparticles for contrast enhancement in bimodal in-vitro OCT imaging

Contrast enhancement is explored in optical coherence tomography images using core NaYF4:Ho3+/Yb3+ and core@shell NaYF4:Ho3+/Yb3+@NaGdF4 nanoparticles. Under 980 nm excitation, core@shell nanoparticles exhibited 2.8 and 3.3 times enhancement at 541 nm and 646 nm emission wavelengths of Ho3+ ions compared to core nanoparticles. Photo-thermal conversion efficiencies were 32% and 20% for core and core@shell nanoparticles. In swept-source optical coherence tomography (SSOCT), core@shell nanoparticles have shown superior contrast, while in photo-thermal optical coherence tomography (PTOCT) core nanoparticles have excelled due to their higher photo-thermal conversion efficiency. The enhancement in contrast to noise ratio obtained is 58 dB. Comparative assessments of scattering coefficients and contrast-to-noise ratios were conducted, providing insights into nanoparticle performance for contrast enhancement in optical coherence tomography.

Visualization Materials Using Silicon-Based Optical Nanodisks (ViSiON) for Enhanced NIR Imaging in Ophthalmology

ViSiON (visualization materials composed of silicon-based optical nanodisks) is presented, which offers a unique optical combination of near-infrared (NIR) optical properties and biodegradability. Initially, numerical simulations are conducted to calculate the total extinction and scattering effects of ViSiON by the diameter-to-thickness ratio, predicting precise control over its scattering properties in the NIR region. A top-down patterning technique is employed to synthesize ViSiON with accurate diameter and thickness control. ViSiON with a 50 nm thickness exhibits scattering properties over 400 times higher than that of 30 nm, rendering it suitable as a contrast agent for optical coherence tomography (OCT), especially in ophthalmic applications. Furthermore, ViSiON possesses inherent biodegradability in media, with ≈95% degradation occurring after 48 h, and the degradation rate can be finely tuned based on the quantity of protein coating applied to the surface. Subsequently, the OCT imaging capability is validated even within vessels smaller than 300 µm, simulating retinal vasculature using a retinal phantom. Then, using an ex ovo chick embryo model, it is demonstrated that ViSiON enhances the strength of protein membranes by 6.17 times, thereby presenting the potential for ViSiON as an OCT imaging probe capable of diagnosing retinal diseases.

Application of aptamer functionalized nanomaterials in targeting therapeutics of typical tumors

Cancer is a major cause of human death all over the world. Traditional cancer treatments include surgery, radiotherapy, chemotherapy, immunotherapy, and hormone therapy. Although these conventional treatment methods improve the overall survival rate, there are some problems, such as easy recurrence, poor treatment, and great side effects. Targeted therapy of tumors is a hot research topic at present. Nanomaterials are essential carriers of targeted drug delivery, and nucleic acid aptamers have become one of the most important targets for targeted tumor therapy because of their high stability, high affinity, and high selectivity. At present, aptamer-functionalized nanomaterials (AFNs), which combine the unique selective recognition characteristics of aptamers with the high-loading performance of nanomaterials, have been widely studied in the field of targeted tumor therapy. Based on the reported application of AFNs in the biomedical field, we introduce the characteristics of aptamer and nanomaterials, and the advantages of AFNs first. Then introduce the conventional treatment methods for glioma, oral cancer, lung cancer, breast cancer, liver cancer, colon cancer, pancreatic cancer, ovarian cancer, and prostate cancer, and the application of AFNs in targeted therapy of these tumors. Finally, we discuss the progress and challenges of AFNs in this field.

Application of nanomaterials in diagnosis and treatment of glioblastoma

Diagnosing and treating glioblastoma patients is currently hindered by several obstacles, such as tumor heterogeneity, the blood-brain barrier, tumor complexity, drug efflux pumps, and tumor immune escape mechanisms. Combining multiple methods can increase benefits against these challenges. For example, nanomaterials can improve the curative effect of glioblastoma treatments, and the synergistic combination of different drugs can markedly reduce their side effects. In this review, we discuss the progression and main issues regarding glioblastoma diagnosis and treatment, the classification of nanomaterials, and the delivery mechanisms of nanomedicines. We also examine tumor targeting and promising nano-diagnosis or treatment principles based on nanomedicine. We also summarize the progress made on the advanced application of combined nanomaterial-based diagnosis and treatment tools and discuss their clinical prospects. This review aims to provide a better understanding of nano-drug combinations, nano-diagnosis, and treatment options for glioblastoma, as well as insights for developing new tools.

Lanthanide-Doped Upconversion Luminescent Nanoparticles-Evolving Role in Bioimaging, Biosensing, and Drug Delivery

Upconverting luminescent nanoparticles (UCNPs) are "new generation fluorophores" with an evolving landscape of applications in diverse industries, especially life sciences and healthcare. The anti-Stokes emission accompanied by long luminescence lifetimes, multiple absorptions, emission bands, and good photostability, enables background-free and multiplexed detection in deep tissues for enhanced imaging contrast. Their properties such as high color purity, high resistance to photobleaching, less photodamage to biological samples, attractive physical and chemical stability, and low toxicity are affected by the chemical composition; nanoparticle crystal structure, size, shape and the route; reagents; and procedure used in their synthesis. A wide range of hosts and lanthanide ion (Ln3+) types have been used to control the luminescent properties of nanosystems. By modification of these properties, the performance of UCNPs can be designed for anticipated end-use applications such as photodynamic therapy (PDT), high-resolution displays, bioimaging, biosensors, and drug delivery. The application landscape of inorganic nanomaterials in biological environments can be expanded by bridging the gap between nanoparticles and biomolecules via surface modifications and appropriate functionalization. This review highlights the synthesis, surface modification, and biomedical applications of UCNPs, such as bioimaging and drug delivery, and presents the scope and future perspective on Ln-doped UCNPs in biomedical applications.

Synthesis of NaYF4:Ho3+/Yb3+ colloidal upconversion phosphor and its application for OCT-based imaging, temperature sensing, fingerprinting and security ink

In this work, an NaYF4:Ho3+/Yb3+ upconversion phosphor in colloidal form was synthesized and then its suitability for image contrast enhancement in optical coherence tomography (OCT) and photothermal (PT) OCT imaging was analysed.

Upconversion luminescent nanomaterials: A promising new platform for food safety analysis

Foodborne diseases have become a significant threat to public health worldwide. Development of analytical techniques that enable fast and accurate detection of foodborne pathogens is significant for food science and safety research. Assays based on lanthanide (Ln) ion-doped upconversion nanoparticles (UCNPs) show up as a cutting edge platform in biomedical fields because of the superior physicochemical features of UCNPs, including negligible autofluorescence, large signal-to-noise ratio, minimum photodamage to biological samples, high penetration depth, and attractive optical and chemical features. In recent decades, this novel and promising technology has been gradually introduced to food safety research. Herein, we have reviewed the recent progress of Ln³⁺-doped UCNPs in food safety research with emphasis on the following aspects: 1) the upconversion mechanism and detection principles; 2) the history of UCNPs development in analytical chemistry; 3) the in-depth state-of-the-art synthesis strategies, including synthesis protocols for UCNPs, luminescence, structure, morphology, and surface engineering; 4) applications of UCNPs in foodborne pathogens detection, including mycotoxins, heavy metal ions, pesticide residue, antibiotics, estrogen residue, and pathogenic bacteria; and 5) the challenging and future perspectives of using UCNPs in food safety research. Considering the diversity and complexity of the foodborne harmful substances, developing novel detections and quantification techniques and the rigorous investigations about the effect of the harmful substances on human health should be accelerated.