pH and Glutathione Synergistically Triggered Release and Self-Assembly of Au Nanospheres for Tumor Theranostics

Theranostic agents based on near-infrared absorption which integrate both imaging and therapeutic functions have attracted considerable attention. However, because of the interference signal, indiscriminate treatment usually causes side effects on normal tissues during tumor treatment. To address this limitation, we propose a new synergistically triggered mechanism, release and self-assembly of Au nanospheres, for tumor theranostics based on the synergistic effect of H⁺ and glutathione on the tumor microenvironment. In vitro experiments reveal that Au nanospheres release from Au@ZIF-8 at a high concentration of H⁺ or glutathione. Importantly, Au aggregation only appears in the synergistic effect of glutathione and lower pH and exhibits strong coupling plasmonic resonance absorption in the near-infrared region and can be used as the theranostics agent. This statement was further verified by biological transmission electron microscopy and in vivo imaging. Au@ZIF-8 is stable and produces no photoacoustic signal in normal tissue; in contrast, in the presence of overexpressed glutathione and H⁺, Au nanospheres release from Au@ZIF-8, assemble to aggregates, and exhibit a strong signal at the tumor site for imaging and efficient photothermal therapy. This work provides a new strategy for designing theranostic agents with sequentially responsive steps to avoid interference diagnosis signals from normal tissues and reduce damage to normal tissue during treatment.

[Changes of serum E2 and Otolin-1 levels in postmenopausal women with BPPV]

Objective:To investigate the changes of serum estradiol（E2） and otolith structural protein Otolin-1 levels in postmenopausal women with benign paroxysmal positional vertigo（BPPV）. Method:Forty postmenopausal women diagnosed as primary BPPV were selected as the experimental group. Meanwhile, 40 postmenopausal women without vertigo during the same time were selected as the control group. 4 ml of fasting peripheral venous blood was extracted in the morning, and E2 and Otolin-1 protein levels in serum of the two groups were detected by electrochemiluminescence（ECL） and ELISA, respectively. Result:①The serum level of E2 in the experimental group was（29.11±15.11） pg/ml, which was lower than that in the control group（37.18±12.24） pg/ml（P=0.010）. ②The serum level of Otolin-1 in the experimental group was（361.55±186.14） pg/ml, which was significantly higher than that in the control group（282.61±139.98） pg/ml（P=0.035）. ③Spearman correlation analysis was carried out on the serum levels of Otolin-1 and E2 in the experimental group and the control group, respectively, and no correlation was found between them（P=0.403 and 0.363, respectively）. ④In the control group, age was negatively correlated with serum E2 level（P=0.044, r=-0.320）, suggesting that age was only weakly correlated with E2 level. However, in the experimental group, there was no correlation between the two（P=0.148）. ⑤There was no correlation between age and serum Otolin-1 level in the two groups（P=0.705 and 0.076, respectively）. Conclusion:Compared with postmenopausal patients without vertigo, the level of E2 in postmenopausal BPPV patients decreased, but the level of Otolin-1 increased significantly. Therefore, the serum level of Otolin-1 may be used as a bio-marker to assist the diagnosis and efficacy evaluation of postmenopausal women with BPPV.

Interstitial brachytherapy of oral squamous cell carcinoma with ultrasound-guided iodine-125 radioactive seed implantation

OBJECTIVE

In this study, we investigated the clinical effect of interstitial brachytherapy on oral squamous cell carcinoma (OSCC) with ultrasound or CT-guided 125I radioactive seed implantation.

PATIENTS AND METHODS

116 patients with advanced oral squamous cell carcinoma, who received initial treatment or retreatment, were enrolled. Therein, 35 patients in the control group were treated with external radiation, systemic chemotherapy or conservative treatment, 41 patients in the ultrasound group were treated with ultrasound-guided125I radioactive seed interstitial implantation brachytherapy, and 40 patients in the CT group were treated with CT-guided 125I radioactive seed interstitial implantation. The median follow-up time was 15.0 months. The clinical outcomes were compared.

RESULTS

At the time of one month after treatment, the tumor diameters of the ultrasound group and the CT group were significantly decreased (p<0.05), which were less than the control group (p<0.05), and there was no difference in comparison between the ultrasound group and the CT group (p>0.05). At the time of one month after treatment, the effective rates were significantly higher in the ultrasound group and the CT group than the control group (p<0.001), and there was no difference in comparison between the ultrasound group and the CT group. And there was no difference in comparison of complication between these two groups (p>0.05). At the time of one month after treatment, the VAS scores of pain were significantly lower in the ultrasound group and the CT group than the control group (p<0.05). There were no differences in comparisons of T lymphocyte subset percentages before and after treatment (p>0.05), and T lymphocyte subset percentages in the control group were significantly decreased (p<0.05). The progression-free survivals, median survival times, and survival rates were significantly higher in the ultrasound group and the CT group than those in the control group (p<0.05), and there were no differences in comparisons between the ultrasound group and the CT group (p>0.05).

CONCLUSIONS

Both ultrasound and CT-guided iodine-125 radioactive seed interstitial implantation brachytherapy in the treatment of OSCC  can achieve better short-term and long-term clinical effects.

Mn-Porphyrin-Based Metal-Organic Framework with High Longitudinal Relaxivity for Magnetic Resonance Imaging Guidance and Oxygen Self-Supplementing Photodynamic Therapy

A nanoplatform for magnetic resonance imaging guidance and oxygen self-supplementing photodynamic therapy (PDT) was constructed on the basis of a porous metal-organic framework (PCN-222(Mn)), which was built by simple Mn-porphyrin ligands and biocompatible Zr⁴⁺ ions. Because of the good dispersibility of Mn³⁺ in the open framework and the high water affinity of the channel, PCN-222(Mn) exhibits a high longitudinal relaxivity of ∼35.3 mM^-1 s^-1 (1.0 T). In addition, it shows good catalytic activity for the conversion of endogenous hydrogen peroxide into oxygen, thereby improving tumor hypoxia during photodynamic therapy. The intravenous injection of PCN-222(Mn) into tumor-bearing mice mode provided good T₁-weighted contrast of the tumor site and effectively inhibited tumor growth upon a single-laser irradiation. The findings provide insights for the development of multifunctional theranostic nanoplatforms based on simple components.

Plasma long non-coding RNAs (lncRNAs) serve as potential biomarkers for predicting breast cancer

OBJECTIVE

Recent studies have suggested that lncRNAs play important regulatory roles in occurrence and progression of many cancers including breast cancer. However, only a small number of lncRNAs have proved to be related to breast cancer. Moreover, the effect of lncRNAs on breast cancer is yet unclear. We aimed at examining whether the expression level of these lncRNAs in our breast cancer patients could be different to normal people, and whether these lncRNAs could serve as potential biomarkers for the diagnosis of breast cancer.

PATIENTS AND METHODS

We selected twelve lncRNAs as the research targets, which were previously found to be abnormally expressed in plasma of other cancers. The expression levels of these lncRNAs were measured by Quantitative Real-time Polymerase Chain Reaction (qRT-PCR) and compared between breast cancer patients and normal people.

RESULTS

The expression levels of plasma lncRNAs (H19, HOTAIR, and RP11-445H22.4) are found to increase significantly in breast cancer patients. The expression levels of other 9 lncRNAs were no significant changed compared with normal people.

CONCLUSIONS

lncRNAs may be related to the occurrence of breast cancer and serve as potential biomarkers for its diagnosis.

Imaging G-Ratio in Multiple Sclerosis Using High-Gradient Diffusion MRI and Macromolecular Tissue Volume

BACKGROUND AND PURPOSE

Remyelination represents an area of great therapeutic interest in multiple sclerosis but currently lacks a robust imaging marker. The purpose of this study was to use high-gradient diffusion MRI and macromolecular tissue volume imaging to obtain estimates of axonal volume fraction, myelin volume fraction, and the imaging g-ratio in patients with MS and healthy controls and to explore their relationship to neurologic disability in MS.

MATERIALS AND METHODS

Thirty individuals with MS (23 relapsing-remitting MS, 7 progressive MS) and 19 age-matched healthy controls were scanned on a 3T MRI scanner equipped with 300 mT/m maximum gradient strength using a comprehensive multishell diffusion MRI protocol. Macromolecular tissue volume imaging was performed to quantify the myelin volume fraction. Diffusion data were fitted to a 3-compartment model of white matter using a spheric mean approach to yield estimates of axonal volume fraction. The imaging g-ratio was calculated from the ratio of myelin volume fraction and axonal volume fraction. Imaging metrics were compared between groups using 2-sided t tests with a Bonferroni correction.

RESULTS

The mean g-ratio was significantly elevated in lesions compared with normal-appearing WM (0.74 vs 0.67, P < .001). Axonal volume fraction (0.17 vs 0.23, P < .001) and myelin volume fraction (0.17 vs 0.25, P < .001) were significantly lower in lesions than normal-appearing WM. Myelin volume fraction was lower in normal-appearing WM compared with that in healthy controls (0.25 vs 0.27, P = .009). Disability, as measured by the Expanded Disability Status Scale, was significantly associated with myelin volume fraction (β = -40.5, P = .001) and axonal volume fraction (β = -41.0, P = .016) in normal-appearing WM.

CONCLUSIONS

The imaging g-ratio may serve as a biomarker for the relative degree of axonal and myelin loss in MS.

Revealing the Adsorption and Decomposition of EP-PTCDI on a Cerium Oxide Surface

Cerium oxide has constantly attracted intense attention during the past decade both in research and industry as an appealing catalyst or a noninert support for catalysts, for instance, in the water-gas shift reaction and hydrogenation of the ketone group. Herein, the cerium oxide surface has been chosen to investigate the adsorption and decomposition behaviors of the N,N'-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxdiimide (EP-PTCDI) molecule by photoelectron spectroscopy. As expected, EP-PTCDI molecules self-assemble on the cerium oxide surface comprising both trivalent and tetravalent cerium at room temperature. Interestingly, the EP-PTCDI molecule exhibits selective adsorption on cerium oxide after the heating treatment. It was found that the ketone group of EP-PTCDI first undergoes hydrogenation after annealing to 400 °C, which is probably related to the fact that high temperature annealing provides sufficient thermal energy to trigger the reaction between the ketone group and trivalent cerium. Furthermore, EP-PTCDI molecules are discovered to start to decompose hierarchically on the ceria substrate from annealing at 400 °C due to the strong molecule-substrate interaction and the effective catalysis by the trivalent cerium, whereas the decomposition sequence of functional groups is revealed to be, first, the ethyl propyl group (-C₅H₉), followed by the hydrogenated ketone (alcohols) group. Finally, our study may provide a new platform for the fundamental understanding of complex organic reactions on the cerium oxide surface.

Reduced SPOCK1 expression inhibits non-small cell lung cancer cell proliferation and migration through Wnt/β-catenin signaling

OBJECTIVE

Accumulating evidence suggests that SPARC/osteonectin, cwcv, and kazal-like domain proteoglycan 1 (SPOCK1) contributes to the initiation and progression of human cancers. However, little is known about the function mechanisms of SPOCK1 in non-small cell lung cancer (NSCLC). The aim of this study was to investigate the molecular mechanism of SPOCK1 in NSCLC.

PATIENTS AND METHODS

The expression levels of SPOCK1 in NSCLC tissues and cell lines were analyzed by qRT-PCR and Western blotting. The proliferative activity of NSCLC cells was determined by MTT and colony formation assays. The transwell assay was used to examine the cell migration and invasive ability. To study the impact of SPOCK1 on Wnt/β‑catenin signaling, we further performed Western blotting for related proteins in this pathway.

RESULTS

We observed that the expression of SPOCK1 at both protein and mRNA levels was also increased in human NSCLC tissues and cell lines. Functionally, down-regulation of SPOCK1 in NSCLC cells markedly suppressed cell proliferation, colony formation, migration and invasion in vitro. Mechanistically, we found that indicated the activation of Wnt/β-catenin pathway was suppressed by SPOCK1 silencing.

CONCLUSIONS

The expression of SPOCK1 served as a tumor promoter, possibly through the Wnt/β-catenin signaling pathway in NSCLC. Targeting SPOCK1 could be a potential therapeutic strategy in NSCLC.

Surface Plasmon Resonance-Enhanced Photoacoustic Imaging and Photothermal Therapy of Endogenous H2 S-Triggered Au@Cu2 O

Smart theranostics agents triggered by endogenous H₂ S with combined activated photoacoustic imaging and photothermal therapy can improve the diagnosis and treatment of colon cancer. However, the low theranostic performance of the current smart theranostics agents after the triggering step has limited their further application. In this work, the theranostic performance of endogenous H₂ S-triggered Au@Cu₂ O for the diagnosis and treatment of colon cancer, which is generated from the localized surface plasmon resonance coupling effect between a noble metal (Au) and a semiconductor (Cu₂ O), is investigated. Compared with Cu₂ O, the prepared H₂ S-triggered Au@Cu₂ O shows a significantly stronger absorption at the near-infrared region, such as a ≈2.1 times change at 808 nm, giving a photothermal conversion efficiency increase of ≈1.2 times. More importantly, Au@Cu₂ O still exhibits good photoacoustic imaging contrast and photothermal properties for treatment of colon cancer in vivo even at very low injection doses. This work not only investigates an endogenous H₂ S-triggered Au@Cu₂ O theranostic agent with enhanced theranostic performance for colon cancer but also provides a novel strategy for designing high-performance theranostic agents.

Tumor pH-Responsive Albumin/Polyaniline Assemblies for Amplified Photoacoustic Imaging and Augmented Photothermal Therapy

Tumor-microenvironment-responsive theranostics have great potential for precision diagnosis and effective treatment of cancer. Polyaniline (PANI) is the first reported pH-responsive organic photothermal agent and is widely used as a theranostic agent. However, tumor pH-responsive PANI-based theranostic agents are not explored, mainly because the conversion from the emeraldine base (EB) to emeraldine salt (ES) state of PANI requires pH < 4, which is lower than tumor acidic microenvironment. Herein, a tumor pH-responsive PANI-based theranostic agent is designed and prepared for amplified photoacoustic imaging guided augmented photothermal therapy (PTT), through intermolecular acid-base reactions between carboxyl groups of bovine serum albumin (BSA) and imine moieties of PANI. The albumin/PANI assemblies (BSA-PANI) can convert from the EB to ES state at pH < 7, accompanied by the absorbance redshift from visible to near-infrared region. Both in vitro and in vivo results demonstrate that tumor acidic microenvironment can trigger both the photoacoustic imaging (PAI) signal amplification and the PTT efficacy enhancement of BSA-PANI assemblies. This work not only highlights that BSA-PANI assemblies overcome the limitation of low-pH protonation, but also provides a facile assembly strategy for a tumor pH-responsive PANI-based nanoplatform for cancer theranostics.

Janus particles: design, preparation, and biomedical applications

Janus particles with an anisotropic structure have emerged as a focus of intensive research due to their diverse composition and surface chemistry, which show excellent performance in various fields, especially in biomedical applications. In this review, we briefly introduce the structures, composition, and properties of Janus particles, followed by a summary of their biomedical applications. Then we review several design strategies including morphology, particle size, composition, and surface modification, that will affect the performance of Janus particles. Subsequently, we explore the synthetic methodologies of Janus particles, with an emphasis on the most prevalent synthetic method (surface nucleation and seeded growth). Following this, we highlight Janus particles in biomedical applications, especially in drug delivery, bio-imaging, and bio-sensing. Finally, we will consider the current challenges the materials face with perspectives in the future directions.

Smart nanomedicine agents for cancer, triggered by pH, glutathione, H2O2, or H2S

Effective tumor diagnosis and therapy have always been a significant but challenging issue. Although nanomedicine has shown great potential for improving the outcomes of tumor diagnosis and therapy, the nonspecial targeted distribution of nanomedicine agents in the whole body causes a low diagnosis signal-to-noise ratio and a potential risk of systemic toxicity. Recently, the development of smart nanomedicine agents with diagnosis and therapy functions that can only be activated by the tumor microenvironment (TME) is regarded as an effective strategy to improve the theranostic sensitivity and selectivity, as well as reduce the potential side effects during treatment. This article will introduce and summarize the latest achievements in the design and fabrication of TME-responsive smart nanomedicine agents, and highlight their prospects for enhancing tumor diagnosis and therapy.

A prospective study of focal brain atrophy, mobility and fitness

BACKGROUND

The parallel decline of mobility and cognition with ageing is explained in part by shared brain structural changes that are related to fitness. However, the temporal sequence between fitness, brain structural changes and mobility loss has not been fully evaluated.

METHODS

Participants were from the Baltimore Longitudinal Study of Aging, aged 60 or older, initially free of cognitive and mobility impairments, with repeated measures of fitness (400-m time), mobility (6-m gait speed) and neuroimaging markers over 4 years (n = 332). Neuroimaging markers included volumes of total brain, ventricles, frontal, parietal, temporal and subcortical motor areas, and corpus callosum. Autoregressive models were used to examine the temporal sequence of each brain volume with mobility and fitness, adjusted for age, sex, race, body mass index, height, education, intracranial volume and APOE ɛ4 status.

RESULTS

After adjustment, greater volumes of total brain and selected frontal, parietal and temporal areas, and corpus callosum were unidirectionally associated with future faster gait speed over and beyond cross-sectional and autoregressive associations. There were trends towards faster gait speed being associated with future greater hippocampus and precuneus. Higher fitness was unidirectionally associated with future greater parahippocampal gyrus and not with volumes in other areas. Smaller ventricle predicted future higher fitness.

CONCLUSION

Specific regional brain volumes predict future mobility impairment. Impaired mobility is a risk factor for future atrophy of hippocampus and precuneus. Maintaining fitness preserves parahippocampal gyrus volume. Findings provide new insight into the complex and bidirectional relationship between the parallel decline of mobility and cognition often observed in older persons.

[The etiological analysis of 260 hospitalized cases with bilateral adrenal lesions]

Objective: To summarize the etiologies of bilateral adrenal lesions and the changes of the disease profile in hospitalized patients. Methods: Bilateral adrenal lesion screening was conducted in all patients admitted to Peking University Third Hospital from 1994 to 2017. The etiologies and disease profiles of bilateral adrenal lesions were retrospectively analyzed. Results: A total of 260 patients with bilateral adrenal lesions were included in the study. There were 146 males and 114 females with a mean age of (55.4±16.2) years. The most common adrenal lesion was bilateral adrenal hyperplasia (75 cases, 28.8%), followed by bilateral adrenal adenomas (71 cases, 27.3%), metastatic carcinoma (51 cases, 19.6%), discordant bilateral adrenal lesions (27 cases, 10.4%), bilateral pheochromocytomas (13 cases, 5.0%), and others. The clear data of endocrine function evaluation could be found in 184 patients. Among them, 111 cases (60.3%) were nonfunctioning lessions, 34 cases (18.5%) with primary aldosteronism, 15 cases (8.1%) with pheochromocytoma, 13 cases (7.1%) with congenital adrenal hyperplasia, 6 cases (3.3%) with primary hypoadrenocorticism, and 5 cases (2.7%) with Cushing syndrome. Using every 8 years as a period of time, the number of hospitalized patients with bilateral adrenal lesions increased with years in three periods (8, 41 and 211 cases, respectively). Conclusions: The most common cause of bilateral adrenal lesions is adrenal hyperplasia in the hospitalized patients. More than half of bilateral adrenal lesions are nonfunctioning. In functional bilateral lesions, primary aldosteronism and pheochromocytoma account for a large proportion.

Macromolecules with Different Charges, Lengths, and Coordination Groups for the Coprecipitation Synthesis of Magnetic Iron Oxide Nanoparticles as T1 MRI Contrast Agents

Considerable efforts have been focused on the exploitation of macromolecule ligands for synthesis of magnetic Fe3O4 nanoparticles as T1 magnetic resonance imaging (MRI) contrast agents, but studies that concern macromolecule ligands with different charges and coordination groups are still limited. Herein, we used poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and polyvinyl alcohol (PVA), which possess negative, positive and neutral charges with carboxylic acid, amino and hydroxyl groups respectively, as templates and stabilizers to fabricate Fe3O4 nanoparticles through coprecipitation reaction. The obtained Fe3O4-PAA, Fe3O4-PAH, and Fe3O4-PVA nanoparticles showed T1 contrast performance with r1 relaxivities of 23.4, 60.3, and 30.6 mM s-1 at 0.5 T (25 °C), and a r2/r1 ratio of 2.62, 3.82, and 7.26, respectively. The cell viability assay revealed that Fe3O4-PAA and Fe3O4-PVA exhibited good biocompatibility, while Fe3O4-PAH displayed high cytotoxicity. In vivo T1-weighted (1 T) mice showed that both Fe3O4-PAA and Fe3O4-PVA were able to display remarkably brighten the contrast enhancement for the mice tumor and kidney sites, but Fe3O4-PAA had better contrast performance. This work highlights that the macromolecule ligands play an important role in the biocompatibility and T1 contrast performance of magnetic Fe3O4 nanoparticles.

Macrophages-Mediated Delivery of Small Gold Nanorods for Tumor Hypoxia Photoacoustic Imaging and Enhanced Photothermal Therapy

Macrophage-mediated delivery of drugs or nanoparticles has great potential in cancer treatment because it can avoid interception by the immune system and cross the blood-vessel barriers to reach the hypoxic regions of tumors. However, macrophage-based delivery system still faces some great challenges such as low theranostics agent loading capacity and hypoxic regions tendency in vivo. Herein, small gold nanorods (AuNRs) were used as the model theranostics agent to design a macrophage-mediated delivery system with high loading quantity for tumor hypoxia photoacoustic (PA) imaging and enhanced photothermal therapy (PTT). AuNRs modified with various thiolated poly(ethylene glycol)s (HS-PEG) via ligand exchange were investigated for toxicity and cell uptake by macrophages. The tumor hypoxic regions tendency of macrophage-loaded Anionic-AuNRs (Anionic-AuNRs@RAW) were verified by in vivo PA imaging and tumor sections. In vivo systemic PTT demonstrated enhanced tumor inhibition of anionic-AuNRs@RAW. This macrophage-mediated delivery system with high loading capacity could be used to enhance the effectiveness of cancer treatment.

T₁-Weight Magnetic Resonance Imaging Performances of Iron Oxide Nanoparticles Modified with a Natural Protein Macromolecule and an Artificial Macromolecule

To optimize the iron oxide nanoparticles as T₁-weight contrast for in vivo magnetic resonance imaging (MRI), numbers of macromolecule ligands have been explored with considerable effort. However, reports refer to the comparison of the T₁-weight contrast performances of iron oxide nanoparticles modified with natural and artificial macromolecule ligands are still limited. In this work, we used a typical natural protein macromolecule (bovine serum albumin, BSA) and an artificial macromolecule (poly(acrylic acid)-poly(methacrylic acid), PMAA-PTTM) as surface ligands to fabricate Fe₃O₄-BSA and Fe₃O₄-PMAA-PTTM nanoparticles with similar size and magnetization by the coprecipitation method and compared their MRI performances. In vitro and in vivo experiments revealed that Fe₃O₄-BSA with lower cytotoxicity exhibited higher r₂/r₁ ratio in solution and darkening contrast enhancement for liver and kidney sites of mice under T₁-weight imaging, while Fe₃O₄-PMAA-PTTM displayed much lower r₂/r₁ ratio in solution and brighter contrast enhancement for liver and kidney sites. These remarkably different MRI behaviors demonstrated that the surface ligands play an important role for optimizing the MRI performance of Fe₃O₄ nanoparticles. We expect these results may facilitate the design of macromolecule ligands for developing an iron oxide⁻based T₁-weight contrast agent.

Fe3O4-ZIF-8 assemblies as pH and glutathione responsive T2-T1 switching magnetic resonance imaging contrast agent for sensitive tumor imaging in vivo

A small Fe3O4 nanoparticles-based T1 contrast agent was assembled into a pH- and glutathione-responsive T2-T1 switching contrast agent, Fe3O4-ZIF-8. In vivo T1-weighted images of mice showed that Fe3O4-ZIF-8 displayed darkening contrast enhancement for liver sites, while darkening to brightening contrast enhancement at tumor sites, giving large inverse contrast for distinguishing the normal and tumor tissues.

Recent progress in H2S activated diagnosis and treatment agents

This review summarizes the recent advances in H₂S detection probes and H₂S-activated tumor treatment agents.

Large-scale synthesis of monodisperse Prussian blue nanoparticles for cancer theranostics via an "in situ modification" strategy

Background

The intrinsic properties of Prussian blue (PB) nanoparticles make them an attractive tool in nanomedicine, including magnetic resonance imaging (MRI), photoacoustic imaging (PAI), and photothermal therapy (PTT) properties. However, there still remains the challenge of their poor dispersible stability in the physiological environment. In this study, we developed an efficient hydrothermal method to address the poor dispersible stability of PB nanoparticles in the physiological environment.

Materials and methods

The concentration of H⁺, the mass of polyvinylpyrrolidone (PVP), and iron sources (K₃[Fe(CN)₆]) are very vital in the preparation of PB nanoparticles. Through exploring the preparation process, optimized PB nanoparticles (OPBs) with excellent physiological stability were prepared. Hydrodynamic diameter and UV-vis absorption properties were measured to verify the stability of the prepared OPBs. Properties of dual-mode imaging, including MRI/PAI, and PTT of OPBs were investigated both in vitro and in vivo. In addition, the in vivo biosafety of OPBs was systematically assessed.

Results

OPBs were stable in different environments including various media, pH, and temperatures for at least 90 days, indicating that they are suitable for biomedical application via intravenous administration and easily stored in a robust environment. Compared with other research into the synthesis of PB nanoparticles, the “in situ modification” synthesis of PB nanoparticles had advantages, including a simple process, low cost, and easy mass preparation. OPBs showed no significant signs of toxicity for 90 days. As a proof of concept, the OPBs served as dual-mode image contrast agents and photothermal conversion agents for cancer diagnosis and therapy both in vitro and in vivo.

Conclusion

Our findings suggest a facile but efficient strategy with low cost to address the poor dispersible stability of PB nanoparticles in physiological environments. This will promote the development of further clinical transformations of PB nanoparticles, especially in cancer theranostics.

Ultrasmall WO3- x@γ-poly-l-glutamic Acid Nanoparticles as a Photoacoustic Imaging and Effective Photothermal-Enhanced Chemodynamic Therapy Agent for Cancer

Synergistic treatment strategies for cancer have attracted increasing attention owing to their enhanced therapeutic effects compared with monotherapy. Chemodynamic therapy (CDT) is an emerging and thriving in situ treatment for cancer owing to its high regioselectivity and activation only by endogenous substances. However, the therapeutic effects of CDT are hindered by low reaction speeds. Here, ultrasmall WO_{3- x}@γ-poly-l-glutamic acid (WO_{3- x}@γ-PGA) nanoparticles (NPs) with good photoacoustic and photothermal properties were prepared, and their chemodynamic performance based on a Fenton-like reaction was explored due to its good catalytic effect. The synergistic treatment effect was also investigated by photothermal-enhanced CDT based on single WO_{3- x}@γ-PGA NPs using a penetrating near-infrared-II laser both in vitro and in vivo. This work provides an effective treatment for cancer and further develops the CDT.