Unveiling the Spatiotemporal and Dose Responses within a Single Live Cancer Cell to Photoswitchable Upconversion Nanoparticle Therapeutics Using Hybrid Hyperspectral Stimulated Raman Scattering and Transient Absorption Microscopy.

Photodynamic therapy (PDT) provides an alternative approach to targeted cancer treatment, but the therapeutic mechanism of advanced nanodrugs applied to live cells and tissue is still not well understood. Herein, we employ the hybrid hyperspectral stimulated Raman scattering (SRS) and transient absorption (TA) microscopy developed for real-time in vivo visualization of the dynamic interplay between the unique photoswichable lanthanide-doped upconversion nanoparticle-conjugated rose bengal and triphenylphosphonium (LD-UCNP@CS-Rb-TPP) probe synthesized and live cancer cells. The Langmuir pharmacokinetic model associated with SRS/TA imaging is built to quantitatively track the uptakes and pharmacokinetics of LD-UCNP@CS-Rb-TPP within cancer cells. Rapid SRS/TA imaging quantifies the endocytic internalization rates of the LD-UCNP@CS-Rb-TPP probe in individual HeLa cells, and the translocation of LD-UCNP@CS-Rb-TPP from mitochondria to cell nuclei monitored during PDT can be associated with mitochondria fragmentations and the increased nuclear membrane permeability, cascading the dual organelle ablations in cancer cells. The real-time SRS spectral changes of cellular components (e.g., proteins, lipids, and DNA) observed reflect the PDT-induced oxidative damage and the dose-dependent death pattern within a single live cancer cell, thereby facilitating the real-time screening of optimal light dose and illumination duration controls in PDT. This study provides new insights into the further understanding of drug delivery and therapeutic mechanisms of photoswitchable LD-UCNP nanomedicine in live cancer cells, which are critical in the optimization of nanodrug formulations and development of precision cancer treatment in PDT.

Mitochondria-Targeting Type-I Photodrug: Harnessing Caspase-3 Activity for Pyroptotic Oncotherapy.

Precise control of cellular signaling events during programmed cell death is crucial yet challenging for cancer therapy. The modulation of signal transduction in cancer cells holds promise but is limited by the lack of efficient, biocompatible, and spatiotemporally controllable approaches. Here we report a photodynamic strategy that modulates both apoptotic and pyroptotic cell death by altering caspase-3 protein activity and the associated signaling crosstalk. This strategy employs a mitochondria-targeting, near-infrared activatable probe (termed M-TOP) that functions via a type-I photochemical mechanism. M-TOP is less dependent on oxygen and more effective in treating drug-resistant cancer cells, even under hypoxic conditions. Our study shows that higher doses of M-TOP induce pyroptotic cell death via the caspase-3/gasdermin-E pathway, whereas lower doses lead to apoptosis. This photodynamic method is effective across diverse gasdermin-E-expressing cancer cells. Moreover, the M-TOP mediated shift from apoptotic to pyroptotic modulation can evoke a controlled inflammatory response, leading to a robust yet balanced immune reaction. This effectively inhibits both distal tumor growth and postsurgical tumor recurrence. This work demonstrates the feasibility of modulating intracellular signaling through the rational design of photodynamic anticancer drugs.

Targeted inhibition of PTPN22 is a novel approach to alleviate osteogenic responses in aortic valve interstitial cells and aortic valve lesions in mice.

BACKGROUND: Calcific aortic valve disease (CAVD) is the most prevalent valvular disease and has high morbidity and mortality. CAVD is characterized by complex pathophysiological processes, including inflammation-induced osteoblastic differentiation in aortic valve interstitial cells (AVICs). Novel anti-CAVD agents are urgently needed. Protein tyrosine phosphatase nonreceptor type 22 (PTPN22), an intracellular nonreceptor-like protein tyrosine phosphatase, is involved in several chronic inflammatory diseases, including rheumatoid arthritis and diabetes. However, it is unclear whether PTPN22 is involved in the pathogenesis of CAVD. METHODS: We obtained the aortic valve tissue from human and cultured AVICs from aortic valve. We established CAVD mice model by wire injury. Transcriptome sequencing, western bolt, qPCR, and immunofluorescence were performed to elucidate the molecular mechanisms. RESULTS: Here, we determined that PTPN22 expression was upregulated in calcific aortic valve tissue, AVICs treated with osteogenic medium, and a mouse model of CAVD. In vitro, overexpression of PTPN22 induced osteogenic responses, whereas siRNA-mediated PTPN22 knockdown abolished osteogenic responses and mitochondrial stress in the presence of osteogenic medium. In vivo, PTPN22 ablation ameliorated aortic valve lesions in a wire injury-induced CAVD mouse model, validating the pathogenic role of PTPN22 in CAVD. Additionally, we discovered a novel compound, 13-hydroxypiericidin A 10-O-α-D-glucose (1 → 6)-ß-D-glucoside (S18), in a marine-derived Streptomyces strain that bound to PTPN22 with high affinity and acted as a novel inhibitor. Incubation with S18 suppressed osteogenic responses and mitochondrial stress in human AVICs induced by osteogenic medium. In mice with aortic valve injury, S18 administration markedly alleviated aortic valve lesions. CONCLUSION: PTPN22 plays an essential role in the progression of CAVD, and inhibition of PTPN22 with S18 is a novel option for the further development of potent anti-CAVD drugs. Therapeutic inhibition of PTPN22 retards aortic valve calcification through modulating mitochondrial dysfunction in AVICs.

A swallowable X-ray dosimeter for the real-time monitoring of radiotherapy.

Monitoring X-ray radiation in the gastrointestinal tract can enhance the precision of radiotherapy in patients with gastrointestinal cancer. Here we report the design and performance, in the gastrointestinal tract of rabbits, of a swallowable X-ray dosimeter for the simultaneous real-time monitoring of absolute absorbed radiation dose and of changes in pH and temperature. The dosimeter consists of a biocompatible optoelectronic capsule containing an optical fibre, lanthanide-doped persistent nanoscintillators, a pH-sensitive polyaniline film and a miniaturized system for the wireless readout of luminescence. The persistent luminescence of the nanoscintillators after irradiation can be used to continuously monitor pH without the need for external excitation. By using a neural-network-based regression model, we estimated the radiation dose from radioluminescence and afterglow intensity and temperature, and show that the dosimeter was approximately five times more accurate than standard methods for dose determination. Swallowable dosimeters may help to improve radiotherapy and to understand how radiotherapy affects tumour pH and temperature.

Surface Engineering of Lanthanide Nanoparticles for Oncotherapy.

Surface-modified lanthanide nanoparticles have been widely developed as an emerging class of therapeutics for cancer treatment because they exhibit several unique properties. First, lanthanide nanoparticles exhibit a variety of diagnostic capabilities suitable for various image-guided therapies. Second, a large number of therapeutic molecules can be accommodated on the surface of lanthanide nanoparticles, which can simultaneously achieve combined cancer therapy. Third, multivalent targeting ligands on lanthanide nanoparticles can be easily modified to achieve high affinity and specificity for target cells. Last but not least, lanthanide nanoparticles can be engineered for spatially and temporally controlled tumor therapy, which is critical for developing precise and personalized tumor therapy. Surface-modified lanthanide-doped nanoparticles are widely used in cancer phototherapy. This is due to their unique optical properties, including large anti-Stokes shifts, long-lasting luminescence, high photostability, and the capacity for near-infrared or X-ray excitation. Upon near-infrared irradiation, these nanoparticles can emit ultraviolet to visible light, which activates photosensitizers and photothermal agents to destroy tumor cells. Surface modification with special ligands that respond to tumor microenvironment changes, such as acidic pH, hypoxia, or redox reactions, can turn lanthanide nanoparticles into a smart nanoplatform for light-guided tumor chemotherapy and gene therapy. Surface-engineered lanthanide nanoparticles can include antigens that elicit tumor-specific immune responses, as well as immune activators that boost immunity, allowing distant and metastatic tumors to be eradicated. The design of ligands and surface chemistry is crucial for improving cancer therapy without causing side effects. In this Account, we classify surface-modified lanthanide nanoparticles for tumor therapy into four main domains: phototherapy, radiotherapy, chemotherapy, and biotherapy. We begin by introducing fundamental bioapplications and then discuss recent developments in tumor phototherapy (photodynamic therapy and photothermal therapy), radiotherapy, chemotherapy, and biotherapy (gene therapy and immunotherapy). We also assess the viability of a variety of strategies for eliminating tumor cells through innovative pathways. Finally, future opportunities and challenges for the development of more efficient lanthanide nanoprobes are discussed.

Low-Dose NIR-II Preclinical Bioimaging Using Liposome-Encapsulated Cyanine Dyes.

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) provides a powerful tool for in vivo structural and functional imaging in deep tissue. However, the lack of biocompatible contrast agents with bright NIR-II emission has hindered its application in fundamental research and clinical trials. Herein, a liposome encapsulation strategy for generating ultrabright liposome-cyanine dyes by restricting dyes in the hydrophobic pockets of lipids and inhibiting the aggregation, as corroborated by computational modeling, is reported. Compared with free indocyanine green (ICG, an US Food and Drug Administration-approved cyanine dye), liposome-encapsulated ICG (S-Lipo-ICG) shows a 38.7-fold increase in NIR-II brightness and enables cerebrovascular imaging at only one-tenth dose over a long period (30 min). By adjusting the excitation wavelength, two liposome-encapsulated cyanine dyes (S-Lipo-ICG and S-Lipo-FD1080) enable NIR-II dual-color imaging. Moreover, small tumor nodules (2-5 mm) can be successfully distinguished and removed with S-Lipo-ICG image-guided tumor surgery in rabbit models. This liposome encapsulation maintains the metabolic pathway of ICG, promising for clinical implementation.

Lanthanide-Nucleotide Coordination Nanoparticles for STING Activation.

Activation of the stimulator of interferon genes (STING) is essential for blocking viral infections and eliciting antitumor immune responses. Local injection of synthetic STING agonists, such as 2'3'-cGAMP [cGAMP = cyclic 5'-guanosine monophosphate (cGMP)-adenosine monophosphate (AMP)], is a promising approach to enhance antiviral functions and cancer immunotherapy. However, the application of such agonists has been hindered by complicated synthetic procedures, high doses, and unsatisfactory systemic immune responses. Herein, we report the design and synthesis of a series of 2'3'-cGAMP surrogates in nanoparticle formulations formed by reactions of AMP, GMP, and coordinating lanthanides. These nanoparticles can stimulate the type-I interferon (IFN) response in both mouse macrophages and human monocytes. We further demonstrate that the use of europium-based nanoparticles as STING-targeted adjuvants significantly promotes the maturation of mouse bone-marrow-derived dendritic cells and major histocompatibility complex class I antigen presentation. Dynamic molecular docking analysis revealed that these nanoparticles bind with high affinity to mouse STING and human STING. Compared with soluble ovalbumin (OVA), subcutaneously immunized europium-based nanovaccines exhibit significantly increased production of primary and secondary anti-OVA antibodies (∼180-fold) in serum, as well as IL-5 (∼28-fold), IFN-γ (∼27-fold), and IFN-α/ß (∼4-fold) in splenocytes ex vivo. Compared with the 2'3'-cGAMP/OVA formulation, subcutaneous administration of nanovaccines significantly inhibits B16F10-OVA tumor growth and prolongs the survival of tumor-bearing mice in both therapeutic and protective models. Given the rich supramolecular chemistry with lanthanides, this work will enable a readily accessible platform for potent humoral and cellular immunity while opening new avenues for cost-effective, highly efficient therapeutic delivery of STING agonists.

Marine-Derived Piericidin Diglycoside S18 Alleviates Inflammatory Responses in the Aortic Valve via Interaction with Interleukin 37.

Calcific aortic valve disease (CAVD) is a valvular disease frequently in the elderly individuals that can lead to the valve dysfunction. Osteoblastic differentiation of human aortic valve interstitial cells (HAVICs) induced by inflammation play a crucial role in CAVD pathophysiological processes. To date, no effective drugs for CAVD have been established, and new agents are urgently needed. Piericidin glycosides, obtained from a marine-derived Streptomyces strain, were revealed to have regulatory effects on mitochondria in previous studies. Here, we discovered that 13-hydroxypiericidin A 10-O-α-D-glucose (1→6)-ß-D-glucoside (S18), a specific piericidin diglycoside, suppresses lipopolysaccharide- (LPS) induced inflammatory responses of HAVICs by alleviating mitochondrial stress in an interleukin (IL)-37-dependent manner. Knockdown of IL-37 by siRNA not only exaggerated LPS-induced HAVIC inflammation and mitochondrial stress but also abrogated the anti-inflammatory effect of S18 on HAVICs. Moreover, S18 alleviated aortic valve lesions in IL-37 transgenic mice of CAVD model. Microscale thermophoresis (MST) and docking analysis of five piericidin analogues suggested that diglycosides, but not monoglycosides, exert obvious IL-37-binding activity. These results indicate that S18 directly binds to IL-37 to alleviate inflammatory responses in HAVICs and aortic valve lesions in mice. Piericidin diglycoside S18 is a potential therapeutic agent to prevent the development of CAVD.

Monocytes augment inflammatory responses in human aortic valve interstitial cells via ß2-integrin/ICAM-1-mediated signaling.

OBJECTIVE: Inflammatory infiltration in aortic valves promotes calcific aortic valve disease (CAVD) progression. While soluble extracellular matrix (ECM) proteins induce inflammatory responses in aortic valve interstitial cells (AVICs), the impact of monocytes on AVIC inflammatory responses is unknown. We tested the hypothesis that monocytes enhance AVIC inflammatory responses to soluble ECM protein in this study. METHODS: Human AVICs isolated from normal aortic valves were cocultured with monocytes and stimulated with soluble ECM protein (matrilin-2). ICAM-1 and IL-6 productions were assessed. YAP and NF-κB phosphorylation were analyzed. Recombinant CD18, neutralizing antibodies against ß2-integrin or ICAM-1, and inhibitor of YAP or NF-κB were applied. RESULTS: AVIC expression of ICAM-1 and IL-6 was markedly enhanced by the presence of monocytes, although matrilin-2 did not affect monocyte production of ICAM-1 or IL-6. Matrilin-2 up-regulated the expression of monocyte ß2-integrin and AVIC ICAM-1, leading to monocyte-AVIC adhesion. Neutralizing ß2-integrin or ICAM-1 in coculture suppressed monocyte adhesion to AVICs and the expression of ICAM-1 and IL-6. Recombinant CD18 enhanced the matrilin-2-induced ICAM-1 and IL-6 expression in AVIC monoculture. Further, stimulation of coculture with matrilin-2 induced greater YAP and NF-κB phosphorylation. Inhibiting either YAP or NF-κB markedly suppressed the inflammatory response to matrilin-2 in coculture. CONCLUSION: Monocyte ß2-integrin interacts with AVIC ICAM-1 to augment AVIC inflammatory responses to soluble matrilin-2 through enhancing the activation of YAP and NF-κB signaling pathways. Infiltrated monocytes may promote valvular inflammation through cell-cell interaction with AVICs to enhance their sensitivity to damage-associated molecular patterns.

Visit-to-Visit Fasting Glucose Variability in Young Adulthood and Nonalcoholic Fatty Liver Disease in Middle Age.

CONTEXT: Diabetes has a bidirectional association with nonalcoholic fatty liver disease (NAFLD) and increases the risk of cirrhosis and related complications. OBJECTIVE: To investigate the association between visit-to-visit fasting glucose (FG) variability in early adulthood and NAFLD in middle age. METHODS: This prospective cohort study included 2467 Black and White adults aged 18 to 30 years at baseline (1985-1986) who were followed over 25 years in the Coronary Artery Risk Development in Young Adults Study. FG variability measures included coefficient of variation about the mean FG (CV-FG), the SD of FG (SD-FG), and the average real variability of FG (ARV-FG) across 25 years (year 0, 7, 10, 15, 20, and 25 examinations). NAFLD was defined as liver attenuation ≤ 40 Hounsfield units on computed tomography scan at year 25 examination after excluding other causes of hepatic steatosis. RESULTS: Of the 2467 participants, 241 (9.8%) had NAFLD at year 25. In multivariate analysis, the odds ratio for NAFLD was 2.80 (95% CI, 1.69-4.64; P trend < 0.001) for the fourth quartile vs first quartile of CV-FG after adjusting for confounding variables, including mean FG. Similar results were observed for SD-FG and ARV-FG. CONCLUSION: Greater visit-to-visit FG variability in early adulthood was associated with higher risk of NAFLD in middle age independent of mean FG level. FG variability may help identify individuals at high risk for NAFLD.

Pro-inflammatory mediators released by activated monocytes promote aortic valve fibrocalcific activity.

BACKGROUND: Calcific aortic valve disease (CAVD) is the most prevalent heart valve disorder in the elderly. Valvular fibrocalcification is a characteristic pathological change. In diseased valves, monocyte accumulation is evident, and aortic valve interstitial cells (AVICs) display greater fibrogenic and osteogenic activities. However, the impact of activated monocytes on valular fibrocalcification remains unclear. We tested the hypothesis that pro-inflammatory mediators from activated monocytes elevate AVIC fibrogenic and osteogenic activities. METHODS AND RESULTS: Picro-sirius red staining and Alizarin red staining revealed collagen and calcium depositions in cultured human AVICs exposed to conditioned media derived from Pam3CSK4-stimulated monocytes (Pam3 CM). Pam3 CM up-regulated alkaline phosphatase (ALP), an osteogenic biomarker, and extracellular matrix proteins collagen I and matrix metalloproteinase-2 (MMP-2). ELISA analysis identified high levels of RANTES and TNF-α in Pam3 CM. Neutralizing RANTES in the Pam3 CM reduced its effect on collagen I and MMP-2 production in AVICs while neutralizing TNF-α attenuated the effect on AVIC ALP production. In addition, Pam3 CM induced NF-κB and JNK activation. While JNK mediated the effect of Pam3 CM on collagen I and MMP-2 production, NF-κB was critical for the effect of Pam3 CM on ALP production in AVICs. CONCLUSIONS: This study demonstrates that activated monocytes elevate the fibrogenic and osteogenic activities in human AVICs through a paracrine mechanism. TNF-α and RANTES mediate the pro-fibrogenic effect of activated monocytes on AVICs through activation of JNK, and TNF-α also activates NF-κB to elevate AVIC osteogenic activity. The results suggest that infiltrated monocytes elevate AVIC fibrocalcific activity to promote CAVD progression.

A multifunctional Fenton nanoagent for microenvironment-selective anti-biofilm and anti-inflammatory therapy.

Bacterial biofilm infections are intractable to traditional antibiotic treatment and usually cause persistent inflammation. Chemodynamic therapy (CDT) based on the Fenton reaction has recently emerged as a promising anti-biofilm strategy. However, the therapeutic efficacy of current Fenton agents often suffers from inefficient Fenton activity and lacks anti-inflammatory capability. Herein, FePS3 nanosheets (NSs) are explored for the first time as novel microenvironment-selective therapeutic nanoagents for bacterial biofilm infections with both self-enhanced Fenton activity for an anti-biofilm effect and reactive oxygen species (ROS) scavenging properties for an anti-inflammatory effect. In biofilms with acidic microenvironments, FePS3 NSs release Fe2+ to generate toxic ROS by Fenton reaction and reductive [P2S6]4- to enhance the Fenton activity by reducing Fe3+ to Fe2+. In the surrounding normal tissues with neutral pH, FePS3 NSs scavenge ROS by reductive [P2S6]4- with an anti-inflammatory effect. This work demonstrates multifunctional Fenton nanoagents with microenvironment-selective ROS generation and elimination properties for effective treatment of bacterial biofilm infections with both anti-biofilm and anti-inflammatory effects.

High-Specificity In Vivo Tumor Imaging Using Bioorthogonal NIR-IIb Nanoparticles.

Lanthanide-based NIR-IIb nanoprobes are ideal for in vivo imaging. However, existing NIR-IIb nanoprobes often suffer from low tumor-targeting specificity, limiting their widespread use. Here the application of bioorthogonal nanoprobes with high tumor-targeting specificity for in vivo NIR-IIb luminescence imaging and magnetic resonance imaging (MRI) is reported. These dual-modality nanoprobes can enhance NIR-IIb emission by 20-fold and MRI signal by twofold, compared with non-bioorthogonal nanoprobes in murine subcutaneous tumors. Moreover, these bioorthogonal probes enable orthotopic brain tumor imaging. Implementation of bio-orthogonal chemistry significantly reduces the nanoprobe dose and hence cytotoxicity, providing a paradigm for real-time in vivo visualization of tumors.

Emerging strategies in developing multifunctional nanomaterials for cancer nanotheranostics.

Cancer involves a collection of diseases with a common trait - dysregulation in cell proliferation. At present, traditional therapeutic strategies against cancer have limitations in tackling various tumors in clinical settings. These include chemotherapeutic resistance and the inability to overcome intrinsic physiological barriers to drug delivery. Nanomaterials have presented promising strategies for tumor treatment in recent years. Nanotheranostics combine therapeutic and bioimaging functionalities at the single nanoparticle level and have experienced tremendous growth over the past few years. This review highlights recent developments of advanced nanomaterials and nanotheranostics in three main directions: stimulus-responsive nanomaterials, nanocarriers targeting the tumor microenvironment, and emerging nanomaterials that integrate with phototherapies and immunotherapies. We also discuss the cytotoxicity and outlook of next-generation nanomaterials towards clinical implementation.

Self-Adjuvanted Molecular Activator (SeaMac) Nanovaccines Promote Cancer Immunotherapy.

Neoantigen-based immunotherapy is a promising treatment option for many types of cancer. However, its efficacy and abscopal effect are limited by impotent neoantigens, high treatment costs, and complications due to action of adjuvants. Here, the design and synthesis of nanovaccines are reported, based on self-adjuvanted, polymer nanoparticles with in vivo neoantigen-harvesting and molecular activating capabilities. These nanovaccines inhibit tumor growth significantly and prolong the survival of tumor-bearing mice in both colon carcinoma 26 (CT26) and B16-F10 tumor models. Mechanistic studies suggest that as-synthesized nanovaccines can promote dendritic cell maturation and accumulation expeditiously in lymph nodes, leading to the expansion of cytotoxic CD8+ T cells. Moreover, these nanovaccines elicit abscopal effects in CT26 and B16-F10 tumors without the need for adjuvants or immune checkpoint inhibitors. Combined with an anti-PD-L1 antibody, nanovaccines can evoke robust, long-term memory immune response, as evidenced by tumor growth inhibition and high survival rates (∼ 67%) over 90 days. These results highlight the potential of using self-adjuvanted nanovaccines as a simple, safe, and affordable strategy to boost neoantigen-based cancer immunotherapy.

Lanthanide-Activated Nanoparticles: A Toolbox for Bioimaging, Therapeutics, and Neuromodulation.

Owing to their unique features, the past decade has witnessed rapid developments of lanthanide-activated nanoparticles for biological applications. These include highly tunable upconverting and downshifting photoluminescence when illuminated in deep tissue, excellent photostability against blinking and bleaching effects, biocompatibility through versatile surface modification, and ease of achieving multifunctionality, as well as satisfactory signal output. These attributes make lanthanide-doped nanoparticles an ideal toolbox for advanced bioimaging and next-generation therapeutics.The interest in lanthanide-doped nanoparticles for biomedical research arises from their unique optical properties in response to deep-tissue-penetrable light sources. Upon near-infrared irradiation, these nanoparticles with properly doped emitters display photon upconversion with large anti-Stokes shifts and broad-spectrum tunability from the ultraviolet to the visible. It is also possible to achieve orthogonal photoluminescence with variations in wavelength and lifetime. Coupled with surface ligands, dyes, biomolecules, or other types of functional nanomaterials, lanthanide-doped nanoparticles offer new opportunities for applications in bioimaging, advanced oncotherapy, and neuromodulation. Given the possibility of locating downshifting luminescence at "biological transmission windows", exquisite design of lanthanide-doped nanoparticles also enables deep-tissue imaging with high spatial resolution. In addition, these nanoparticles can respond to high-energy photons, such as X-rays, to trigger nonradioactive and radiative pathways, making it possible to develop high-sensitivity X-ray detectors. Precise control of paramagnetic lanthanide ions in nanocrystal lattices also provides advanced materials for high-performance magnetic resonance imaging in medical diagnostics and biomedical research. Full consideration of fundamental attributes of lanthanide-doped nanoparticles will facilitate the design of multifunctional and sensitive probes and improve diagnostic and therapeutic outcomes.In this Account, we categorize various lanthanide-activation strategies into three modes: near-infrared excitation, X-ray irradiation, and magnetic field stimulation. We introduce energy manipulations in upconverting, downshifting, and persistence luminescence in spectral and time domains and discuss how they can be applied in biological practices. We assess general design principles for lanthanide-activated nanosystems with multiple modalities of bioimaging, oncotherapy, and neuromodulation. We also review the current state-of-the-art in the field of lanthanide-based theranostic nanoplatforms, with particular emphasis on energy conversion and nano-/biointerfacing as well as emerging bioapplications. In this context, we also highlight recent advances in controlling optical properties of nanoplatforms for single- or multimodal bioimaging, stimulus-responsive phototherapy, and optogenetics. Finally, we discuss future opportunities and challenges of this exciting research field.

Combating the Coronavirus Pandemic: Early Detection, Medical Treatment, and a Concerted Effort by the Global Community.

The World Health Organization (WHO) has declared the outbreak of 2019 novel coronavirus, known as 2019-nCoV, a pandemic, as the coronavirus has now infected over 2.6 million people globally and caused more than 185,000 fatalities as of April 23, 2020. Coronavirus disease 2019 (COVID-19) causes a respiratory illness with symptoms such as dry cough, fever, sudden loss of smell, and, in more severe cases, difficulty breathing. To date, there is no specific vaccine or treatment proven effective against this viral disease. Early and accurate diagnosis of COVID-19 is thus critical to curbing its spread and improving health outcomes. Reverse transcription-polymerase chain reaction (RT-PCR) is commonly used to detect the presence of COVID-19. Other techniques, such as recombinase polymerase amplification (RPA), loop-mediated isothermal amplification (LAMP), clustered regularly interspaced short palindromic repeats (CRISPR), and microfluidics, have allowed better disease diagnosis. Here, as part of the effort to expand screening capacity, we review advances and challenges in the rapid detection of COVID-19 by targeting nucleic acids, antigens, or antibodies. We also summarize potential treatments and vaccines against COVID-19 and discuss ongoing clinical trials of interventions to reduce viral progression.

AIEgen-coupled upconversion nanoparticles eradicate solid tumors through dual-mode ROS activation.

Reactive oxygen species (ROS) are essential for the regulation of antitumor immune responses, where they could induce immunogenic cell death, promote antigen presentation, and activate immune cells. Here, we report the development of near-infrared (NIR)-driven immunostimulants, based on coupling upconversion nanoparticles with aggregation-induced emission luminogens (AIEgens), to integrate the immunological effects of ROS for enhanced adaptive antitumor immune responses. Intratumorally injected AIEgen-upconversion nanoparticles produce high-dose ROS under high-power NIR irradiation, which induces immunogenic cell death and antigen release. These nanoparticles can also capture the released antigens and deliver them to lymph nodes. Upon subsequent low-power NIR treatment of lymph nodes, low-dose ROS are generated to further trigger efficient T cell immune responses through activation of dendritic cells, preventing both local tumor recurrence and distant tumor growth. The utility of dual-mode pumping power on AIEgen-coupled upconversion nanoparticles offers a powerful and controllable platform to activate adaptive immune systems for tumor immunotherapy.

Improving Cancer Immunotherapy Outcomes Using Biomaterials.

Immunotherapy has made great strides in improving clinical outcomes in cancer treatment. However, few patients exhibit adequate response rates for key outcome measures and desired long-term responses, and they often suffer systemic side effects due to the dynamic nature of the immune system. This has motivated a search for alternative strategies to improve unsatisfactory immunotherapeutic outcomes. In recent years, biomaterial-assisted immunotherapy has shown promise in cancer treatment with improved therapeutic efficacy and reduced side effects. These biomaterials have illuminated fundamental mechanisms underlying the immunoediting process, while greatly improving the efficacy of chimeric antigen receptor (CAR) T-cell therapy, cancer vaccine therapy, and immune checkpoint blockade therapy. This Minireview discusses recent advances in engineered biomaterials that address limitations associated with conventional cancer immunotherapies.

In Vivo Tumor Visualization through MRI Off-On Switching of NaGdF4 -CaCO3 Nanoconjugates.

The development of high-performance contrast agents in magnetic resonance imaging (MRI) has recently received considerable attention, as they hold great promise and potential as a powerful tool for cancer diagnosis. Despite substantial achievements, it remains challenging to develop nanostructure-based biocompatible platforms that can generate on-demand MRI signals with high signal-to-noise ratios and good tumor specificity. Here, the design and synthesis of a new class of nanoparticle-based contrast agents comprising self-assembled NaGdF4 and CaCO3 nanoconjugates is reported. In this design, the spatial confinement of the T1 source (Gd3+ ions) leads to an "OFF" MRI signal due to insufficient interaction between the protons and the crystal lattices. However, when immersed in the mildly acidic tumor microenvironment, the embedded CaCO3 nanoparticles generate CO2 bubbles and subsequently disconnect the nanoconjugate, thus resulting in an "ON" MRI signal. The in vivo performance of these nanoconjugates shows more than 60-fold contrast enhancement in tumor visualization relative to the commercially used contrast agent Magnevist. This work presents a significant advance in the construction of smart MRI nanoprobes ideally suited for deep-tissue imaging and target-specific cancer diagnosis.