Use Of Upconversion Nanoparticles Research Articles

Aptamer-free upconversion nanoparticle/silk biosensor system for low-cost and highly sensitive detection of antibiotic residues

The detection of antibiotics is crucial for safeguarding the environment, ensuring food safety, and promoting human health. However, developing a rapid, convenient, low-cost, and sensitive method for antibiotic detection presents significant challenges. Herein, an aptamer-free biosensor was successfully constructed using upconversion nanoparticles (UCNPs) coated with silk fibroin (SF), based on Förster resonance energy transfer (FRET) and the charge-transfer effect, for detecting roxithromycin (RXM). A synergistic FRET efficiency was achieved by utilizing alizarin red and RXM complexes as energy acceptors, with UCNP as the energy donor, and immobilizing an ultrathin SF protein corona within 10 nm. The biosensor detects RXM in deionized water with high sensitivity primarily through monolayer adsorption, with a detection range of 1.0 nM–141.6 nM and a detection limit as low as 0.68 nM. The performance of this biosensor was compared with the ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method for detecting antibiotics in river water separately and a strong correlation between the two methods was observed. The biosensor exhibited long-term stability in aqueous solutions (up to 60 d) with no attenuation of fluorescence intensity. Furthermore, the biosensor's applicability extended to the highly sensitive detection of other antibiotics, such as azithromycin. This study introduces a low-cost, eco-friendly, and highly sensitive method for antibiotic detection, with broad potential for future applications in environmental, healthcare, and food-related fields.

Upconversion-Mediated Optogenetics for the Treatment of Surgery-Induced Postoperative Neurocognitive Dysfunction.

Perioperative neurocognitive disorder (PND) is a common complication in surgical patients. While many interventions to prevent PND have been studied, the availability of treatment methods is limited. Thus, it is crucial to delve into the mechanisms of PND, pinpoint therapeutic targets, and develop effective treatment approaches. In this study, reduced dorsal tenia tecta (DTT) neuronal activity was found to be associated with tibial fracture surgery-induced PND, indicating that a neuronal excitation-inhibition (E-I) imbalance could contribute to PND. Optogenetics in the DTT brain region was conducted using upconversion nanoparticles (UCNPs) with the ability to convert 808 nm near-infrared light to visible wavelengths, which triggered the activation of excitatory neurons with minimal damage in the DTT brain region, thus improving cognitive impairment symptoms in the PND model. Moreover, this noninvasive intervention to modulate E-I imbalance showed a positive influence on mouse behavior in the Morris water maze test, which demonstrates that UCNP-mediated optogenetics is a promising tool for the treatment of neurological imbalance disorders.

New ketoxime ester-amine photoinitiator based on charge transfer complex for free radical LED polymerization

Recently, visible-light polymerization has received increasing attention because of the development of LED sources and the innovation of photopolymerization technology, which is derived from different strategies to design photoinitiating systems such as the construction of D-π-A-type photoinitiators or the use of up-conversion nanoparticles. However, the association of electron donor and acceptor molecules to form a charge-transfer complex (CTC) for polymerization has rarely been reported. Hence, a ketoxime ester (PFO) with a pentafluorophenone ring as an electron-defect acceptor has been designed and synthesized as a photosensitizer. Our investigation results showed that CTCs could be formed by associating PFO with amines that contain electron-rich rings and process a better absorption property in the visible-light region than PFO. Moreover, the two kinds of free radicals with high photoactivity were generated from CTCs via photochemical transformation, such as intermolecular charge transfer and α-cleavage, which can play a role in initiating the polymerization of acrylate monomers, and the efficiency of initiating polymerization is higher than that of PFO alone under LED@395–425 nm irradiation.

Upconversion-Powered Photoelectrochemical Bioanalysis for DNA Sensing.

In this work, we report a new concept of upconversion-powered photoelectrochemical (PEC) bioanalysis. The proof-of-concept involves a PEC bionanosystem comprising a NaYF4:Yb,Tm@NaYF4 upconversion nanoparticles (UCNPs) reporter, which is confined by DNA hybridization on a CdS quantum dots (QDs)/indium tin oxide (ITO) photoelectrode. The CdS QD-modified ITO electrode was powered by upconversion absorption together with energy transfer effect through UCNPs for a stable photocurrent generation. By measuring the photocurrent change, the target DNA could be detected in a specific and sensitive way with a wide linear range from 10 pM to 1 μM and a low detection limit of 0.1 pM. This work exploited the use of UCNPs as signal reporters and realized upconversion-powered PEC bioanalysis. Given the diversity of UCNPs, we believe it will offer a new perspective for the development of advanced upconversion-powered PEC bioanalysis.

Advancements and applications of upconversion nanoparticles in wound dressings.

Wound healing is a complex process that requires effective management to prevent infections and promote efficient tissue regeneration. In recent years, upconversion nanoparticles (UCNPs) have emerged as promising materials for wound dressing applications due to their unique optical properties and potential therapeutic functionalities. These nanoparticles possess enhanced antibacterial properties when functionalized with antibacterial agents, helping to prevent infections, a common complication in wound healing. They can serve as carriers for controlled drug delivery, enabling targeted release of therapeutic agents to the wound site, allowing for tailored treatment and optimal healing conditions. These nanoparticles possess the ability to convert near-infrared (NIR) light into the visible and/or ultraviolet (UV) regions, making them suitable for therapeutic (photothermal therapy and photodynamic therapy) and diagnostic applications. In the context of wound healing, these nanoparticles can be combined with other materials such as hydrogels, fibers, metal-organic frameworks (MOFs), graphene oxide, etc., to enhance the healing process and prevent the growth of microbial infections. Notably, UCNPs can act as sensors for real-time monitoring of the wound healing progress, providing valuable feedback to healthcare professionals. Despite their potential, the use of UCNPs in wound dressing applications faces several challenges. Ensuring the stability and biocompatibility of UCNPs under physiological conditions is crucial for their effective integration into dressings. Comprehensive safety and efficacy evaluations are necessary to understand potential risks and optimize UCNP-based dressings. Scalability and cost-effectiveness of UCNP synthesis and manufacturing processes are important considerations for practical applications. In addition, efficient incorporation of UCNPs into dressings, achieving uniform distribution, poses an important challenge that needs to be addressed. Future research should prioritize addressing concerns regarding stability and biocompatibility, efficient integration into dressings, rigorous safety evaluation, scalability, and cost-effectiveness. The purpose of this review is to critically evaluate the advantages, challenges, and key properties of UCNPs in wound dressing applications to provide insights into their potential as innovative solutions for enhancing wound healing outcomes. We have provided a detailed description of various types of smart wound dressings, focusing on the synthesis and biomedical applications of UCNPs, specifically their utilization in different types of wound dressings.

A novel enzymatic biosensor for CIP in food based on UCNPs and colorimetric strategy of potassium titanium oxalate

A novel enzymatic biosensor was developed for the determination of ciprofloxacin (CIP) using upconversion nanoparticles (UCNPs) and the color development strategy of potassium titanium oxalate (PTO). The presence of CIP triggers the specific recognition of CIP by the aptamer, which leads to the dissociation of PDA-encapsulated magnetic nanoparticles (Fe3O4 @PDA-Apt) from the horseradish peroxidase-functionalized UCNPs (cDNA-UCNPs-HOR) and facilitates fluorescence recovery. Accordingly, CIP demonstrated the ability to indirectly alter the quantity of H2O2, where PTO could selectively interact with H2O2, leading to the formation of yellow peroxo-titanic acid, which enabled the colorimetric detection of CIP. Under ideal conditions, the linear ranges for fluorescence and colorimetry were 10–1000 µg L−1 and 100–1000 µg L−1, respectively, with detection limits (LOD) of 2.1 and 16.7 µg L−1. Finally, the precision and accuracy of the method were validated with HPLC and achieved satisfactory results (P > 0.05).

Manipulation phonon energy for improved thermometric sensitivity of only-core nanoparticles

Luminescent nano thermometry using upconversion nanoparticles (UCNPs) has gained attention in recent years due to its potential advantages over conventional methods. One major challenge in practical applications of nanothermometers is achieving high sensitivity. While efforts have been made to improve the sensitivity of individual core nanoparticles, there are few reports on incorporating phonon energy and local crystal field distortions to improve the sensitivity of only-core upconversion nanoparticles. In this study, we propose a new approach to improve the sensitivity of only-core UCNPs thermometers through phonon tuning and self-photogenic heating. We use the ratio of the intensity of two bands (centered at 520 nm and 540 nm) based on dopant Er3+ as a referenced signal for optical sensing of temperature. We use a host material NaYF4 doped with K+ to produce local crystal field changes at the interface, modifying the phonon energy mode. As the temperature increases, the vibrational mode cannot propagate smoothly along the crystal axis throughout the crystal, disrupting the direction of lattice heat conduction and producing a significant local thermal effect on the nanoscale. This leads to a significant increase in sensitivity, and we achieve an enhanced thermal sensitivity more than twice that of conventional core-only nanoparticles.

Near-Infrared Light-Controlled MicroRNA-21-Loaded Upconversion Nanoparticles to Promote Bone Formation in the Midpalatal Suture.

Rapid maxillary expansion (RME) is a common therapy for maxillary transverse deficiency. However, relapses after RME usually occur because of insufficient bone formation. MicroRNA-21 (miR-21) was reported as an important post-transcriptional modulator for osteogenesis. Herein, a photocontrolled miR-21 (PC-miR-21)-loaded nanosystem using upconversion nanoparticles (UCNPs) modified with poly(ether imide) (PEI), i.e., UCNPs@PEI@PC-miR-21, was constructed to promote bone formation in the midpalatal suture. UCNPs@PEI was constructed as the light transducer and delivery carrier. The UCNPs@PEI@PC-miR-21 nanocomplexes have good aqueous dispersibility and biocompatibility. The in vitro cell experiment suggested that UCNPs@PEI could protect PC-miR-21 from biodegradation and release PC-miR-21 into the cytoplasm under near-infrared light (NIR) irradiation. Furthermore, UCNPs@PEI@PC-miR-21 upregulated the expression of the osteogenic key markers, ALP, RUNX2, and COL1A1, at the levels of both genes and proteins. Besides, the results of the in vivo RME mice models further corroborated that photocontrollable UCNPs@PEI@PC-miR-21 accelerated bone formation with upregulating osteogenic markers of ALP, RUNX2, and osteoprotegerin and inducing fewer osteoclasts formation. In conclusion, UCNPs@PEI@PC-miR-21 nanoparticles with a NIR light could facilitate the remote and precise delivery of exogenous miR-21 to the midpalatal suture to promote bone formation during RME. This work represents a cutting-edge approach of gene therapy to promote osteogenesis in the midpalatal suture during RME and provides a frontier scientific basis for later clinical treatment.

Bilayer-Coating Strategy for Hydrophobic Nanoparticles Providing Colloidal Stability, Functionality, and Surface Protection in Biological Media.

The surface chemistry of nanoparticles is a key step on the pathway from particle design towards applications in biologically relevant environments. Here, a bilayer-based strategy for the surface modification of hydrophobic nanoparticles is introduced that leads to excellent colloidal stability in aqueous environments and good protection against disintegration, while permitting surface functionalization via simple carbodiimide chemistry. We have demonstrated the excellent potential of this strategy using upconversion nanoparticles (UCNPs), initially coated with oleate and therefore dispersible only in organic solvents. The hydrophobic oleate capping is maintained and a bilayer is formed upon addition of excess oleate. The bilayer approach renders protection towards luminescence loss by water quenching, while the incorporation of additional molecules containing amino functions yields colloidal stability and facilitates the introduction of functionality. The biological relevance of the approach was confirmed with the use of two model dyes, a photosensitizer and a nitric oxide (NO) probe that, when attached to the surface of the UCNPs, retained their functionality to produce singlet oxygen and detect intracellular NO, respectively. We present a simple and fast strategy to protect and functionalize inorganic nanoparticles in biological media, which is important for controlled surface engineering of nanosized materials for theranostic applications.

Strategie zur Beschichtung von hydrophoben Nanopartikeln mit einer Doppelschicht für kolloidale Stabilität, Funktionalität und Oberflächenschutz in biologischen Medien

AbstractDie Oberflächenchemie von Nanopartikeln ist ein wichtiger Schritt auf dem Weg vom Partikeldesign zur Anwendung in biologisch relevanten Umgebungen. Hier wird eine auf einer Doppelschicht (Bilayer) basierende Strategie für die Oberflächenmodifikation von hydrophoben Nanopartikeln vorgestellt, die diesen eine ausgezeichnete kolloidale Stabilität in wässriger Umgebung und einen guten Schutz gegen Auflösung verleiht und gleichzeitig eine Oberflächenfunktionalisierung durch einfache Carbodiimid‐Kopplungschemie ermöglicht. Wir haben das herausragende Potenzial dieser Strategie anhand von Upconversion‐Nanopartikeln (UCNPs) demonstriert, die ursprünglich mit Oleat beschichtet und daher nur in organischen Lösungsmitteln dispergierbar waren. Die hydrophobe Oleatbeschichtung bleibt dabei erhalten und bildet nach Zugabe von weiterem Oleat eine Doppelschicht. Dieser Ansatz schützt vor Lumineszenzlöschung durch Wassermoleküle, während der Einbau zusätzlicher Moleküle mit Aminogruppen in die Doppelschicht deren kolloidale Stabilität erhöht und die Funktionalisierbarkeit erleichtert. Die biologische Relevanz des Ansatzes wurde durch die Verwendung von zwei Modellfarbstoffen gezeigt, einem Photosensibilisator und einer Stickoxid‐ (NO−) Sonde, die, wenn sie an die Oberfläche der UCNPs gebunden sind, ihre Funktionalität zur Erzeugung von Singulett‐Sauerstoff bzw. zum Nachweis von intrazellulärem NO beibehalten. Wir stellen eine einfache und schnelle Methode zum Schutz und zur Funktionalisierung von anorganischen Nanopartikeln in biologischen Medien vor, die für die kontrollierte Oberflächengestaltung von Nanomaterialien für theranostische Anwendungen wichtig ist.

Solid optical tissue phantom tools based on upconverting nanoparticles for biomedical applications.

Phantoms play a critical role in the development of biophotonics techniques. There is a lack of novel phantom tools in the emerging field of upconverting nanoparticles (UCNPs) for biophotonics application. This work provides a range of UCNP-based phantom tools and a manufacturing recipe to bridge the gap and accelerate the development of UCNP-based biophotonics applications. The study aims to provide a well-characterized UCNP-based solid phantom recipe and set of phantom tools to address a wide range of UCNP-based biophotonics applications. A solid phantom recipe based on silicone matrix was developed to manufacture UCNP-based phantoms. A lab built UCNP imaging system was used to characterize upconverted fluorescence emission of phantoms for linearity, homogeneity, and long-term stability. A photon time-of-flight spectroscopy technique was used to characterize the optical properties of the phantoms. In total, 24 phantoms classified into 4 types, namely homogeneous, multilayer, inclusion, and base phantoms, were manufactured. The phantoms exhibit linear behavior over the dosage range of UCNPs. The phantoms were found to be stable over a limited observed period of 4 months with a coefficient of variation of . The deep tissue imaging case showed that increasing the thickness of tissue reduced the UCNP emission. A first-of-its-kind UCNP-based solid phantom recipe was developed, and four types of UCNP phantom tools to explore biophotonics applications were presented. The UCNP phantoms exhibited a linear behavior with dosage and were stable over time. An example case showed the potential use of the phantom for deep tissue imaging applications. With recent advance in the use of UCNPs for biophotonics, we believe our recipe and tools will play a pivotal role in the growth of the UCNPs for biophotonics applications.

Smart Drug-Delivery System of Upconversion Nanoparticles Coated with Mesoporous Silica for Controlled Release.

Drug-delivery vehicles have garnered immense interest in recent years due to unparalleled progress made in material science and nanomedicine. However, the development of stimuli-responsive devices with controllable drug-release systems (DRSs) is still in its nascent stage. In this paper, we designed a two-way controlled drug-release system that can be promoted and prolonged, using the external stimulation of near-infrared light (NIR) and protein coating. A hierarchical nanostructure was fabricated using upconversion nanoparticles (UCNPs)-mesoporous silica as the core-shell structure with protein lysozyme coating. The mesoporous silica shell provides abundant pores for the loading of drug molecules and a specific type of photosensitive molecules. The morphology and the physical properties of the nanostructures were thoroughly characterized. The results exhibited the uniform core-shell nanostructures of ~four UCNPs encapsulated in one mesoporous silica nanoparticle. The core-shell nanoparticles were in the spherical shape with an average size of 200 nm, average surface area of 446.54 m2/g, and pore size of 4.6 nm. Using doxorubicin (DOX), a chemotherapy agent as the drug model, we demonstrated that a novel DRS with capacity of smart modulation to promote or inhibit the drug release under NIR light and protein coating, respectively. Further, we demonstrated the therapeutic effect of the designed DRSs using breast cancer cells. The reported novel controlled DRS with dual functionality could have a promising potential for chemotherapy treatment of solid cancers.

Upconversion Nanoparticles for Cancer Therapy

Lanthanide‐doped upconversion nanoparticles (UCNPs) are anti‐Stokes emitters, which can produce higher‐energy ultraviolet/visible and near‐infrared (NIR) luminescence when excited with low‐energy NIR light. They are featured with nonphotobleaching, sharp emission peaks, superstability, low toxicity, low imaging background, and functional multimodality. These characteristics endow them to be useful as nanoprobes for diagnostic applications and imaging‐guided cancer therapy. Importantly, the ability to convert tissue‐penetrating NIR light into visible and ultraviolet range can expedite Fenton‐ or Fenton‐based processes in chemical dynamic therapy (CDT), activate photosensitizers (PSs) to produce singlet oxygen in photodynamic therapy (PDT), and regulate light‐controlled drug delivery processes for efficacious cancer therapy. The past decade witnessed fast progress of UCNPs as agents in single‐mode therapy or combined therapies in the forefront researches on fighting cancer. This review summarizes the fundamental roles of UCNPs in cancer therapy, highlights types of cell deaths induced by excessive reactive oxygen species (ROS), and showcases cutting‐edge applications in combined cancer therapies as well as imaging‐guided cancer therapy. Challenges and outlook on the use of UCNPs for future directions in cancer therapy are also discussed.

NIR-Responsive Photodynamic Nanosystem Combined with Antitumor Immune Optogenetics Bacteria for Precise Synergetic Therapy.

Photodynamic therapy (PDT) and immunotherapy are considered promising methods for the treatment of tumors. However, these treatment systems are still suffering from shortcomings such as hypoxia, easy metastasis, and delayed immune response during PDT. Therefore, it is still challenging to establish a programmed and rapid response immune combination therapy platform. Here, we construct a two-step synergetic therapy platform for the treatment of primary tumors and distant tumors using upconversion nanoparticles (UCNPs) and engineered bacteria as therapeutic media. In the first step, erbium ion (Er3+)-doped UCNPs act as a photoswitcher to activate the photosensitizer ZnPc to produce 1O2 for primary tumor therapy. In the second step, thulium ion (Tm3+)-doped UCNPs can emit blue-violet light under the excitation of near-infrared (NIR) light to activate the engineered bacteria to produce interferon (INF-γ) and release them in the intestine, which can not only treat tumors directly but also act with PDT to regulate immune pathways to activate the immune system, resulting in a joint immunotherapy effect to inhibit the growth of distant tumors. As a new type of programmatic combination therapy, we have proved that this platform can jointly activate the body's immune system during PDT and immunization treatment and can effectively inhibit tumor metastasis.

Expanded solar absorption spectrum to improve photoelectrochemical oxygen evolution reaction: Synergistic effect of upconversion nanoparticles and ZnFe2O4/TiO2

The key to increasing photocatalytic activity is to maximize solar spectrum utilization and minimize the recombination of photosynthetic carriers. Along with ZnFe2O4 for visible light absorption, we designed a novel heterojunction photoelectrode using upconversion nanoparticles (UCNPs) with near-infrared (NIR) light absorption to improve solar absorption efficiency. We fabricated a UCNP-decorated ZnFe2O4/TiO2 photocatalyst (UCNPs-ZFO/TiO2) by sequentially drop-casting ZFO nanoparticles and UCNPs onto TiO2 nanopillars grown on a transparent fluorine-doped tin oxide (FTO) substrate. The UCNP-ZFO/TiO2 exhibited a significantly higher photocurrent density of 0.795 mA cm−2 compared to that of the pristine TiO2 (0.260 mA cm−2). The applied bias photon-to-current efficiency of UCNP-ZFO/TiO2 was 4.1 times higher than that of TiO2, and its photoanode had the lowest charge transfer resistance and highest charge density among the prepared photoelectrodes. This implies that the combination of UCNPs and ZFO on the TiO2 photoanode can be an effective strategy to significantly improve photoelectrochemical performance owing to the synergetic utilization of NIR light by UCNPs and that of visible light by the ZFO nanoparticles.

A first approach to the use of upconversion nanoparticles to measure fluorescent tracers in water: a proof of concept

In this work we use lanthanide based NaYF4:Er3+, Yb3+ upconversion nanoparticles (UCNP) to detect ppb-level sensitibity of a xanthene dye, Rhodamine B (RB) dye, under NIR excitation. A static energy transfer was observed between the luminescent UCNP energy donors and RB acceptor in aqueous solution for three different sizes of UCNP. No specific covalent functionalization of the UCNPs was performed providing a direct method of detection, particularly promising in natural systems where the interfering fluorescence background is a detrimental limitation to the performance of the detection method. This procedure is a first approach to be applied in estuarine and coastal zone where the high content of suspended particulate matter prevents the detection of tracers.

A turn-on fluorescence sensor for rapid sensing of ATP based on luminescence resonance energy transfer between upconversion nanoparticles and Cy3 in vivo or vitro

Adenosine triphosphate (ATP) is an energy molecule of significant importance, and, the monitoring of ATP in living cells is considerable for the clinical diagnosis of many related diseases, including cancer. Upconversion nanoparticles (UCNPs) have recently been attracting widespread interest in biomedical applications due to their chemical and thermal stability, high sensitivity, good biocompatibility, and excellent tissue penetration. Herein, a Cy3-aptamer-cDNA- UCNPs nanosensor was synthesized, based on the luminescence resonance energy transfer (LRET) between UCNPs and Cy3 for monitoring ATP in living cells. It showed a selective sensing ability for ATP levels by changes of fluorescence intensity of UNCPs at 536 nm. The investigated biosensor showed a precise, efficient detection with sufficient selectivity which was achieved through the optimization of conditions. In the range of 1–1000 μM, the ATP-induced changes of the fluorescence intensity were linearly proportional to the ATP concentrations. Furthermore, the cytotoxicity assay revealed that the UCNPs sensor exhibited favorable biocompatibility, implicating the use of UCNPs in vivo imaging. This study highlights the potential of using a combination of UCNPs and ATP-binding aptamer to design an ATP-activatable probe for fluorescence-mediated imaging in living cells. These results implied that the nanosensor can be applicable for the monitoring of intracellular ATP by fluorescence imaging and the quantitative analysis of biological liquids.

Rose Bengal and Future Directions in Larynx Tumor Photodynamic Therapy.

Photodynamic Therapy (PDT) seems to be a promising method in the treatment of larynx tumor tissues. The aim of the present analysis was the study of photosensitizer penetration of larynx tissue associated with the application of PDT invitro. This study is based on the use of photosensitive compounds Rose Bengal (RB) that selectively accumulate in larynx tissue. The selection of the study group of patients who will undergo surgery in accordance with medical principles was of key importance for the project. Histopathological examination of samples subjected to PDT revealed numerous changes in the morphology of the cancer cells and surrounding tissues. After PDT treatment, the number of tumor cells decreased compared with the cells number before PDT and the arrangement was relatively loose. After PDT with RB the nuclei morphology was incomplete and fragmented. The effects of the applied PDT of larynx invitro were assessed under an optical microscope. The future directions in larynx tumor PDT with the use of upconversion nanoparticles (UPCNP) is also discussed.

Long-Term Tri-Modal In Vivo Tracking of Engrafted Cartilage-Derived Stem/Progenitor Cells Based on Upconversion Nanoparticles.

Cartilage-derived stem/progenitor cells (CSPCs) are a potential choice for seed cells in osteal and chondral regeneration, and the outcomes of their survival and position distribution in vivo form the basis for the investigation of their mechanism. However, the current use of in vivo stem cell tracing techniques in laboratories is relatively limited, owing to their high operating costs and cytotoxicity. Herein, we performed tri-modal in vivo imaging of CSPCs during subcutaneous chondrogenesis using upconversion nanoparticles (UCNPs) for 28 days. Distinctive signals at accurate positions were acquired without signal noise from X-ray computed tomography, magnetic resonance imaging, and upconversion luminescence. The measured intensities were all significantly proportional to the cell numbers, thereby enabling real-time in vivo quantification of the implanted cells. However, limitations of the detectable range of cell numbers were also observed, owing to the imaging shortcomings of UCNPs, which requires further improvement of the nanoparticles. Our study explores the application value of upconversion nanomaterials in the tri-modal monitoring of implanted stem cells and provides new perspectives for future clinical translation.

The Use of Upconversion Nanoparticles in Prostate Cancer Photodynamic Therapy.

Photodynamic Therapy (PDT) is a cancer treatment that uses light, a photosensitizer, and oxygen to destroy tumors. This article is a review of approaches to the treatment of prostate cancer applying upconversion nanoparticles (UCNPs). UCNPs have become a phenomenon that are rapidly gaining recognition in medicine. They have proven to be highly selective and specific and present a powerful tool in the diagnosis and treatment of prostate cancer. Prostate cancer is a huge health problem in Western countries. Its early detection can significantly improve patients’ prognosis, but currently used diagnostic methods leave much to be desired. Recently developed methodologies regarding UCNP research between the years 2021 and 2014 for prostate cancer PDT will also be discussed. Current limitations in PDT include tissue irradiation with visible wavelengths that have a short tissue penetration depth. PDT with the objectives to synthesize UCNPs composed of a lanthanide core with a coating of adsorbed dye that will generate fluorescence after excitation with near-infrared light to illuminate deep tissue is a subject of intense research in prostate cancer.