Site-Specific Modification of Single Domain Antibodies by Enzyme-Immobilized Magnetic Beads.

Nanobodies as imaging agents and drug conjugates have shown great potential for cancer diagnostics and therapeutics. However, site-specific modification of a nanobody with microbial transglutaminase (mTGase) encounters problems in protein separation and purification. Here, we describe a facile yet reliable strategy of immobilizing mTGase onto magnetic beads for site-specific nanobody modification. The mTGase immobilized on magnetic beads (MB-mTGase) exhibits catalytic activity nearly equivalent to that of the free mTGase, with good reusability and universality. Magnetic separation simplifies the protein purification step and reduces the loss of nanobody bioconjugates more effectively than size exclusion chromatography. Using MB-mTGase, we demonstrate site-specific conjugation of nanobodies with fluorescent dyes and polyethylene glycol molecules, enabling targeted immunofluorescence imaging and improved circulation dynamics and tumor accumulation in vivo. The combined advantages of MB-mTGase method, including high conjugation efficiency, quick purification, less protein loss, and recycling use, are promising for site-specific nanobody functionalization and biomedical applications.

Achieving High Performance Stretchable Conjugated Polymers via Donor Structure Engineering.

A backbone engineering strategy is developed to tune the mechanical and electrical properties of conjugated polymer semiconductors. Four Donor-Acceptor (D-A) polymers, named PTDPPSe, PTDPPTT, PTDPPBT, and PTDPPTVT, are synthesized using selenophene (Se), thienothiophene (TT), bithiophene (BT), and thienylenevinylenethiophene (TVT) as the donors and siloxane side chain modified diketopyrrolopyrrole (DPP) as acceptor. The influences of the donor structure on the polymer energy level, film morphology, molecular stacking, carrier transport properties, and tensile properties are all examined. The films of PTDPPSe show the best stretchability with crack-onset-strain greater than 100%, but the worst electrical properties with a mobility of only 0.54 cm2  V-1  s-1 . The replacement of the Se donor with larger conjugated donors, that is, TT, BT, and TVT, significantly improves the mobility of conjugated polymers but also leads to reduced stretchability. Remarkably, PTDPPBT exhibits moderate stretchability with crack-onset-strain ≈50% and excellent electrical properties. At 50% strain, it has a mobility of 2.37 cm2 V-1  s-1 parallel to the stretched direction, which is higher than the mobility of most stretchable conjugated polymers in this stretching state.

Fabrication and application of carbohydrate microarray for analyzing human serum antibody-carbohydrate interaction.

We introduced a strategy for preparing a carbohydrate microarray and demonstrated its utility for characterizing carbohydrate binding and activities. We isolated the lipopolysaccharide (LPS) components from different bacteria and explored the possibility of immobilizing these glycoconjugates on a high-binding polystyrene plate. Carbohydrate-specific combination was examined by observing the binding of the blood group B analogic LPS O-polysaccharide from Escherichia coli on the high-binding polystyrene plate and anti-B from a broad spectra antibody of human blood serum. Strong binding of antibodies was screened, as it was evident that relative response value is two times higher than control. The hybridization results indicated that this method is a reliable technique for the detection of human intestinal bacteria and is expected to be applied in diagnostics and seroepidemiology.

Targeted Therapy of Non-Small Cell Lung Cancer and Liver Cancer: Functional Nanocarriers for the Delivery of Cisplatin and Tissue Factor Pathway Inhibitor-2.

INTRODUCTION: The aim of the study was to construct folic acid-modified PEGylated paramagnetic nanoparticles (MNPs) co-carrying tissue factor pathway inhibitor-2 (TFPI-2) and cisplatin (CDDP), and to study the molecular-targeting and inhibitory effects of the nanocomposite on non-small cell lung cancer (NSCLC) and liver cancer. METHODS: Nanocomposites were prepared using amino-modified iron oxide nanoparticles as carriers, co-loading CDDP and PEGylated FA/TFPI-2. Transmission electron microscopy, UV absorption spectrum, and dynamic light scattering were employed to characterize the morphology, structure, particle size, and zeta potential of the nanocomposite. The phenylenediamine method was used to detect the loading of CDDP, and the CCK-8 assay was used to detect the toxic effect of the nanocomposite on HUVECs, A549, and NCI-H460 cells. In tumor-bearing mice models, the antitumor effects of the nanocomposites were assessed using TUNEL staining (at the molecular level), reverse transcriptase quantitative polymerase chain reaction (at the gene level), hematoxylin and eosin staining (at the cellular level), and the appearance of the mice models. RESULTS: The synthesized FA-MNP/CDDP/TFPI-2 nanocomposite was uniformly dispersed and spherical in shape (approximate diameter: 10 nm). The zeta potential of particles was -9.44 mV, and the average particle size was 25 nm. The loading amount of CDDP was 70.24 µg/mL (23.33%). The nanocomposite was nontoxic to HUVECs, while it showed a favorable inhibitory effect on A549 and NCI-H460 cells. In vivo experiments in mice demonstrated satisfactory imaging properties and therapeutic effects of nanocomposite against liver cancer. DISCUSSION: FA-MNP/CDDP/TFPI-2 may provide insights for the development of new chemotherapeutic drugs.

Role of Molecular Weight in the Mechanical Properties and Charge Transport of Conjugated Polymers Containing Siloxane Side Chains.

The molecular weight is a key factor affecting the properties of conjugated polymers. To determine the critical molecular weights of conjugated polymers modified with siloxane side chains, poly-diketo-pyrrolopyrrole-selenophene (PTDPPSe-5Si) samples with molecular weights ranging from 20 to 350 kDa are synthesized. The critical molecular weight of the polymer is determined in the range of 60-100 kDa by testing the viscosity of the solution. When the molecular weight of the 27-60 kDa polymers is below the critical molecular weight, they exhibit a high crystallinity and low ductility. When the molecular weight of the 100 kDa polymer reaches the critical molecular weight, the crystallinity decreases, and the ductility increases. As the molecular weight increases, the polymer film also gradually changes from brittle to ductile. Furthermore, when the molecular weight of the 315 kDa polymer is much higher than the critical molecular weight, the film exhibits a significant ductility, which results in the polymer films showing no pronounced cracks after high-percentage stretching. Additionally, due to the oriented alignment of the molecular chains caused by stretching, the carrier mobility in the parallel direction becomes 2.14-fold of the initial film.

Tooth Loss Trajectories and Their Association with Functional Disability among Older Chinese Adults: Results from the Chinese Longitudinal Healthy Longevity Survey.

BACKGROUND: Tooth loss becomes more prevalent with age and increases risk of functional disability. However, the strength of tooth loss varies between individuals rather than a uniform loss with age. We aimed to evaluate tooth loss trajectories and their association with functional disability among older Chinese adults. METHODS: We included 16,209 participants aged ≥65 years from five waves of the Chinese Longitudinal Healthy Longevity Survey 2002-2014. The number of teeth, Activities of Daily Living (ADL), and Instrumental ADL (IADL) were assessed at baseline and subsequently every three years. ADL disability and IADL disability were defined as needing any help in any item of the Katz scale and a modified Lawton's scale, respectively. A group-based trajectory model was used to determine tooth loss trajectories based on the self-reported number of teeth and generalized estimating equation models were used to explore associations of tooth loss trajectories with ADL disability and IADL disability. RESULTS: This study identified four tooth loss trajectories, including Progressively Mild Loss (14.4%), Progressively Severe Loss (21.5%), Persistently Severe Loss (45.1%), and Edentulism (19.0%) among older Chinese adults. Compared with the Progressively Mild Loss trajectory, the Progressively Severe Loss (ADL disability: OR=1.45, 95% CI: 1.15-1.84; IADL disability: OR=1.71, 95% CI: 1.47-1.99), Persistently Severe Loss (ADL disability: OR=2.33, 95% CI:1.93-2.82; IADL disability: OR=3.29, 95% CI: 2.82-3.84) and Edentulism (ADL disability: OR=3.25, 95% CI: 2.58-4.09; IADL disability: OR=3.60, 95% CI: 2.93-4.42) trajectories were significantly associated with an increased risk of functional disability with adjustment for potential confounders. CONCLUSION: Four distinct tooth loss trajectories were identified among older adults and those with severe tooth loss trajectories had an increased risk of functional disability than those with a mild loss trajectory.

Anchoring Group Mediated Radiolabeling for Achieving Robust Nanoimaging Probes.

Radiolabeling counts for much in the functionalization of inorganic nanoparticles (NPs) because it endows NPs with high-sensitive imaging capacities apart from providing accurate pharmacokinetic information on the labeled particles, which makes the development of relevant radiolabeling chemistry highly desirable. Herein, a novel Ligand Anchoring Group MEdiated RAdioLabeling (LAGMERAL) method is reported, in which a polyethylene glycol (PEG) ligand with a diphosphonate (DP) terminal group plays a key role. It offers possibilities to radiolabel NPs through the spare coordination sites of the DP anchoring group. Through X-ray absorption spectroscopy studies, the coordination states of the foreign metal ions on the particle surface are investigated. In addition, radioactive Fe3 O4 NPs are prepared by colabeling the particles with 125 I at the outskirt of the particles through a phenolic hydroxyl moiety of the PEG ligand, and 99m Tc at the root of the ligand, respectively. In this way, the stabilities of these types of radiolabeling are compared both in vitro and in vivo to show the advantages of the LAGMERAL method. The outstanding stability of probe and simplicity of the labeling process make the current approach universal for creating advanced NPs with different combinations of functionalities of the inorganic NPs and radioactive properties of the metal radioisotopes.

Plastic lengthening amputation with vascularized bone grafts in children with bone sarcoma: a preliminary report.

BACKGROUND: At present, amputation was widely adopted for young patients when limb salvage was deemed risky with several surgical strategy such as rotationplasty. However, leg length discrepancies and unfavorable cosmetic results were indispensable complication of this strategy. The purpose of this study was to propose a novel reconstruction strategy and evaluate the early clinical and functional outcomes of the strategy. METHODS: Plastic lengthening amputation (PLA) has been developed by lengthening the stump to preserve one additional distal joint for fixing the artificial limb well. The surgical technique and postoperative management were documented, and the functional outcomes were compared with those of traditional amputation (TA). Six pairs of patients matched for age, sex, location, pathological type, and final prosthesis underwent individually designed plastic lengthening amputation with vascularized autografts or traditional amputation between January 2005 and December 2007. All patients were followed, and the locomotor index and the musculoskeletal tumor society score (MSTS) were used to describe and quantitatively grade limb functional outcomes after amputation. The complications and functional outcomes of the patients taken two kinds of procedures were compared. RESULTS: Twelve patients with osteosarcoma or Ewing's sarcoma of either the femur or tibia were included in the study. Six patients underwent plastic lengthening amputations, three of whom also underwent vascular anastomosis. Patients were followed for an average of 48.17 months; bone healing required an average of 3.3 months. No local recurrence was found. The average postoperative locomotor index functional score of the affected limb was 32.67 ± 5.89 in the plastic lengthening amputation group while was 19.50 ± 7.87 in the traditional amputation group. The MSTS functional scores were 22.67 ± 1.33 and 24.17 ± 1.45 at 6 and 12 months for patients in PLA group while 17.00 ± 1.549 and 17.83 ± 1.64 at 6 and 12 months for patients in TA group. CONCLUSIONS: Plastic lengthening amputations with vascularized autografts could preserve the knee joint to improve the function of the amputated limb in selected bone sarcoma patients.

The preparation and characterization of micelles from poly(γ-glutamic acid)-graft-poly(L-lactide) and the cellular uptake thereof.

Chemotherapy is a traditional therapeutic approach for the treatment of many solid tumors, but the poor solubility and low bioavailability of hydrophobic anti-cancer drugs greatly limit their applications. In this article, DOX-loaded micelles were fabricated based on an amphiphilic graft polymer composed of hydrophilic poly(γ-glutamic acid) (γ-PGA) and hydrophobic poly (L-lactide) (PLLA). The structure of the copolymers and the characteristic of the micelles were studied. The release profiles of doxorubicin as a model drug from the micelles were measured. Due to the protonation of the amino group of DOX and the conformational alteration of γ-PGA, the release of DOX from γ-PGA-g-PLLA micelle was faster in the acid condition, which is beneficial to tumor therapy. The cellular uptake of the DOX-loaded γ-PGA-g-PLLA micelle was proved to be a GGT-mediated process.

Ultra-pH-sensitive nanoprobe library with broad pH tunability and fluorescence emissions.

pH is an important physiological parameter that plays a critical role in cellular and tissue homeostasis. Conventional small molecular pH sensors (e.g., fluorescein, Lysosensor) are limited by broad pH response and restricted fluorescent emissions. Previously, we reported the development of ultra-pH-sensitive (UPS) nanoprobes with sharp pH response using fluorophores with small Stokes shifts (<40 nm). In this study, we expand the UPS design to a library of nanoprobes with operator-predetermined pH transitions and wide fluorescent emissions (400-820 nm). A copolymer strategy was employed to fine tune the hydrophobicity of the ionizable hydrophobic block, which led to a desired transition pH based on standard curves. Interestingly, matching the hydrophobicity of the monomers was critical to achieve a sharp pH transition. To overcome the fluorophore limitations, we introduced copolymers conjugated with fluorescence quenchers (FQs). In the micelle state, the FQs effectively suppressed the emission of fluorophores regardless of their Stokes shifts and further increased the fluorescence activation ratios. As a proof of concept, we generated a library of 10 nanoprobes each encoded with a unique fluorophore. The nanoprobes cover the entire physiologic range of pH (4-7.4) with 0.3 pH increments. Each nanoprobe maintained a sharp pH transition (on/off < 0.25 pH) and high fluorescence activation ratio (>50-fold between on and off states). The UPS library provides a useful toolkit to study pH regulation in many pathophysiological indications (e.g., cancer, lysosome catabolism) as well as establishing tumor-activatable systems for cancer imaging and drug delivery.

Local control of giant cell tumors of the long bone after aggressive curettage with and without bone cement.

BACKGROUND: Aggressive curettage has been well established for the treatment of giant cell tumors (GCTs) of the bone. The purpose of this study was to review our experience and evaluate the role of different implant materials in patients with GCTs of the extremities after aggressive curettage. METHODS: A total of 119 patients with GCTs of the long bone were treated at the First Affiliated Hospital of Sun Yat-Sen University between 2004 and 2009. We excluded patients presenting metastases, recurrent tumors, and soft tissue involvement and those with Jaffe pathological grade III. The remaining 65 patients were treated with aggressive curettage using a bone graft or bone cement to fill the cavity. The recurrence rates and functional scores associated with the different fillings were analyzed. RESULTS: Aggressive curettage and bone grafting was performed in 34 cases (52.3%), and aggressive curettage with bone cement was performed in 31 cases (47.7%). The overall recurrence rate after the aggressive intralesional procedures was 35.3% with bone grafting and 12.9% when bone cement was used as an adjuvant filling. The recurrence rate following aggressive curettage and bone grafting was higher than that following aggressive curettage with cement (p = 0.038). The Musculoskeletal Tumor Society (MSTS) score for bone graft patients was 91.1%, which was significantly lower than that for patients treated with bone cement (94.7%). CONCLUSIONS: The use of bone cement was associated with a significantly lower recurrence rate than bone grafting following aggressive intralesional curettage to treat benign giant cell tumors of the long bone. Better MSTS functional results were also observed in the bone cement group compared to the bone graft group.

Chaotropic-anion-induced supramolecular self-assembly of ionic polymeric micelles.

Traditional micelle self-assembly is driven by the association of hydrophobic segments of amphiphilic molecules forming distinctive core-shell nanostructures in water. Here we report a surprising chaotropic-anion-induced micellization of cationic ammonium-containing block copolymers. The resulting micelle nanoparticle consists of a large number of ion pairs (≈60,000) in each hydrophobic core. Unlike chaotropic anions (e.g. ClO4(-)), kosmotropic anions (e.g. SO4(2-)) were not able to induce micelle formation. A positive cooperativity was observed during micellization, for which only a three-fold increase in ClO4(-) concentration was necessary for micelle formation, similar to our previously reported ultra-pH-responsive behavior. This unique ion-pair-containing micelle provides a useful model system to study the complex interplay of noncovalent interactions (e.g. electrostatic, van der Waals, and hydrophobic forces) during micelle self-assembly.

Global trends in incidence of caries in permanent teeth of children aged 5 through 14 years, 1990 through 2019.

BACKGROUND: School-aged children are in the stage of permanent tooth eruption to replace primary teeth and this can be reached at a life stage when their health habits are being formed due to a large amount of time in school. However, data on the global trend in incidence of caries in permanent teeth in school-aged children are sparse. This study aimed to assess the trends in incidence of caries in permanent teeth in children aged 5 through 14 years from 1990 through 2019 at the global, regional, and national levels. METHODS: The authors collected data on incidence of caries in permanent teeth in children aged 5 through 14 years from 1990 through 2019 from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) to assess trends at the global, regional, and national levels. RESULTS: Globally, incident cases of caries in permanent teeth in children aged 5 through 14 years increased by 15.25% from 1990 through 2019, and the incidence rate remained stable during this period, with incidence rates of 34.04% in 1990 and 33.93% in 2019. The incidence rate increased at an average annual percentage change of 0.08% (95% CI, 0.06% to 0.10%) and 0.07% (95% CI, 0.05% to 0.09%) from 1990 through 2019 in low and low-middle sociodemographic index regions, respectively. An increasing trend also was observed in nearly one-half of GBD regions and more than one-half of the world's countries from 1990 through 2019 (P < .05). CONCLUSIONS: Global incidence of caries in permanent teeth remained stable at a high level in children aged 5 through 14 years, but there was a trend toward increasing rates in nearly one-half of sociodemographic index or GBD regions and more than one-half of the world's countries and territories from 1990 through 2019. These findings suggest that caries in permanent teeth is a priority health issue in school-aged children worldwide. PRACTICAL IMPLICATIONS: Reducing free sugar intake and implementing school-based effective caries prevention programs, such as school water fluoridation, provision of fluoride tablets at school, and school dental sealant programs, are needed for school-aged children.

Application of digital impression and model in removable partial dentures for Kennedy classâ andâ ¡dentition defects.

OBJECTIVES: This study aimed to evaluate the application of digital impression and resin model technology in removable partial dentures (RPD) for Kennedy classⅠandⅡdentition defects. METHODS: Patients with Kennedy classⅠorⅡdental defect were selected and grouped in accordance with the following denture production processes: digital impression/resin model/cast cobalt-chromium alloy framework group (group A), digital impression/resin model/laser printed titanium framework group (group B), alginate impression/plaster model/cast cobalt-chromium alloy framework group (group C), and alginate impression/plaster model/laser printed titanium framework group (group D), with 40 cases in each group. The final RPD was examined in place in the mouth, and the evaluation indicators included the retention force of clamp ring, the tightness of connector and base, and the accuracy of occlusion. The evaluation scores of each index were used for analysis on the Kruskal-Wallis rank-sum test. RESULTS: No statistically significant difference in the score of each index was found among the four groups in RPD. CONCLUSIONS: The cast cobalt-chromium alloy and laser-printed titanium framework RPD using digital impression and resin model can meet the clinical restoration requirements of patients with Kennedy classⅠandⅡdentition defects.

Stepwise Ultra-pH-Sensitive Micelles Overcome a pKa Barrier for Systemic Lymph Node Delivery.

While local nanoparticle delivery to lymph nodes is well studied, there are few design criteria for intravenous delivery to the entire lymph node repertoire. In this study, we investigated the effect of NP pH transition on lymph node targeting by employing a series of ultra-pH-sensitive (UPS) polymeric micelles. The UPS library responds to pH thresholds (pKa 6.9, 6.2, and 5.3) over a range of physiological pH. We observed a dependence of intravenous lymph node targeting on micelle pH transition. UPS6.9 (subscript indicates pKa) shows poor lymph node delivery, while UPS5.3 delivers efficiently to lymph node sets. We investigated targeting mechanisms of UPS5.3, observing an accumulation among lymph node lymphatics and a dependence on lymph node-resident macrophages. To overcome the pH-threshold barrier, which limits UPS6.9, we rationally designed a nanoparticle coassembly of UPS6.9 with UPS5.3, called HyUPS. The HyUPS micelle retains the constitutive pH transitions of each polymer, showing stepwise responses to discrete pH thresholds. We demonstrate that HyUPS improves UPS6.9 delivery to lymph nodes, extending this platform for disease detection of lymph node metastasis.

Solvent annealing induced phase separation and dewetting in PMMA∕SAN blend film: film thickness and solvent dependence.

The competition between "dewetting" and "phase separation" behaviors in polymer blend films attracts significant attention in the last decade. The simultaneous phase separation and dewetting in PMMA∕SAN [poly(methyl methacrylate) and poly(styrene-ran-acrylonitrile)] blend ultrathin films upon solvent annealing have been observed for the first time in our previous work. In this work, film thickness and annealing solvent dependence of phase behaviors in this system has been investigated using atomic force microscopy and grazing incidence small-angle X-ray scattering (GISAXS). On one hand, both vertical phase separation and dewetting take place upon selective solvent vapor annealing, leading to the formation of droplet∕mimic-film structures with various sizes (depending on original film thickness). On the other hand, the whole blend film dewets the substrate and produces dispersed droplets on the silicon oxide upon common solvent annealing. GISAXS results demonstrate the phase separation in the big dewetted droplets resulted from the thicker film (39.8 nm). In contrast, no period structure is detected in small droplets from the thinner film (5.1 nm and 9.7 nm). This investigation indicates that dewetting and phase separation in PMMA∕SAN blend film upon solvent annealing depend crucially on the film thickness and the atmosphere during annealing.

Effect of a bioactive glass-based root canal sealer on root fracture resistance ability.

Background/purpose: The root fracture resistance of endodontically treated teeth is decreased significantly, and it is more likely to fracture. This study aimed to evaluate the effect of a novel root canal sealer based on bioactive glass (BG) on root fracture resistance and explore its mechanism. Materials and methods: The BG-based root canal sealer (BG Sealer) was prepared by mixing a kind of bioactive glass (10.8% P2O5, 54.2% SiO2, 35% CaO, mol.%, named PSC), zirconia (ZrO2) powder, sodium alginate (SA) and phosphate solution (PS). A pH meter was used to measure the pH of simulated body fluid (SBF) after immersion with BG Sealer at different time. After preparing the samples of BG sealer with a diameter of 4 mm and a height of 6 mm, the compressive strength was tested by a universal testing machine. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to detect and analyze the mineral status of root canal systems filled with BG Sealer. The push out test was used to measure the push out bond strength of BG Sealer. The fracture resistance of root canals filled with BG Sealer was detected by the compressive loading test. Bioceramic root canal sealer iRoot SP was set as the control group. Results: (1) Physicochemical properties: The pH value of SBF immersed with BG Sealer increased slightly up to 7.68, while the pH of SBF immersed with iRoot SP increased to 12.08. The compressive strength of the novel BG Sealer was 4.62 ± 1.70 MPa, which was lower than that of iRoot SP (P < 0.05). (2) Mineralization: The hydroxyapatite layers were observed on the surface of BG Sealer and iRoot SP after being immersed in SBF for 4 weeks. BG Sealer and iRoot SP were both able to penetrate into the dentin tubules, duplicate the morphology of root canals well, and form a layer of hydroxyapatite. (3) Adhesion to dentin: There was no significant difference between the push out bond strength of the novel BG Sealer and iRoot SP (P > 0.05). (4) Fracture resistance: After immersion in SBF for 4 weeks, the fracture resistance of roots filled with BG Sealer and iRoot SP was 454.16 ± 155.39 N and 445.50 ± 164.73 N, respectively, both of which were not statistically different from that of the roots unprepared and unfilled (394.07 ± 62.12 N) (P > 0.05), whereas higher than that of the roots prepared and unfilled (235.36 ± 83.80 N) (P < 0.05). Conclusion: The novel BG Sealer has good adhesion to the root dentin, can penetrate into the dentin tubules to generate minerals, and meanwhile can improve the fracture resistance of the roots after root canal treatment. It is expected to be a bioactive root canal sealer with good clinical application prospects.

Elucidation of Protonation Cooperativity of a STING-Activating Polymer.

Stimuli-responsive nanomaterials have the potential to improve the performance and overcome existing barriers of conventional nanotherapeutics. Molecular cooperativity design in stimuli-responsive nanomedicine can amplify physiological signals, enabling a cooperative response for improved diagnostic and therapeutic precision. Previously, this work reported an ultra-pH-sensitive polymer, PEG-b-PC7A, that possesses innate immune activating properties by binding to the stimulator of interferon genes (STING) through polyvalent phase condensation. This interaction enhances STING activation and synergizes with the endogenous STING ligand for robust cancer immunotherapy. Despite its successes in innate immune activation, the fundamental physicochemical and pH-responsive properties of PC7A require further investigation. Here, this study elucidates the protonation cooperativity driven by the phase transition of PC7A copolymer. The highly cooperative system displays an "all-or-nothing" proton distribution between highly charged unimer (all) and neutral micelle (nothing) states without gradually protonated intermediates. The binary protonation behavior is further illustrated in pH-precision-controlled release of a representative anticancer drug, ß-lapachone, by PC7A micelles over a noncooperative PE5A polymer. Furthermore, the bimodal distribution of protons is represented by a high Hill coefficient (nH  > 9), featuring strong positive cooperativity. This study highlights the nanoscale pH cooperativity of an immune activating polymer, providing insights into the physicochemical characterization and design parameters for future nanotherapeutics development.

Investigation of excipients impact on polysorbate 80 degradation in biopharmaceutical formulation buffers.

A study on the polysorbate 80 stability in various formulation buffers commonly used in biopharmaceuticals was performed, to investigate the excipients influence on polysorbate 80 degradation. Polysorbate 80 is a common excipient in biopharmaceutical products. However, its degradation will potentially impact the drug product quality, and may trigger protein aggregation and particles formation. Due to the heterogeneity of the polysorbates and the mutual effects with other formulation compositions, the study of polysorbate degradation is challenging. Herein, a real-time stability study was designed and performed. The polysorbate 80 degradation trend was monitored by fluorescence micelle-based assay (FMA), reversed-phase-ultra-performance liquid chromatography-evaporative light scattering detector (RP-UPLC-ELSD) assay, and LC-MS assay. These assays provide orthogonal results to reveal both the micelle-forming capability and the compositional changes of polysorbate 80 in different buffer systems. The degradation occurred after a period of storage under 25 °C in different trend, which indicates the excipients could impact the degradation kinetics. Upon comparison, the degradation is prone to happen in histidine buffer than in acetate, phosphate or citrate buffers. LC-MS confirms oxidation as an independent degradation pathway with detection of the oxidative aldehyde. Thus, it is necessary to pay more attention to the excipients selection and their potential impact on polysorbate 80 stability to achieve longer shelf life for the biopharmaceuticals. Besides, the protective roles of several additives were figured out, which could be applied as potential industrial solutions to the polysorbate 80 degradation issues.

A clinically translatable kit for MRI/NMI dual-modality nanoprobes based on anchoring group-mediated radiolabeling.

Magnetic resonance imaging (MRI)/nuclear medicine imaging (NMI) dual-modality imaging based on radiolabeled nanoparticles has been increasingly exploited for accurate diagnosis of tumor and cardiovascular diseases by virtue of high spatial resolution and high sensitivity. However, significant challenges exist in pursuing truly clinical applications, including massive preparation and rapid radiolabeling of nanoparticles. Herein, we report a clinically translatable kit for the convenient construction of MRI/NMI nanoprobes relying on the flow-synthesis and anchoring group-mediated radiolabeling (LAGMERAL) of iron oxide nanoparticles. First, homogeneous iron oxide nanoparticles with excellent performance were successfully obtained on a large scale by flow synthesis, followed by the surface anchoring of diphosphonate-polyethylene glycol (DP-PEG) to simultaneously render the underlying nanoparticles biocompatible and competent in robust labeling of radioactive metal ions. Moreover, to enable convenient and safe usage in clinics, the DP-PEG modified nanoparticle solution was freeze-dried and sterilized to make a radiolabeling kit followed by careful evaluations of its in vitro and in vivo performance and applicability. The results showed that 99mTc labeled nanoprobes are effectively obtained with a labeling yield of over 95% in 30 minutes after simply injecting Na[99mTcO4] solution into the kit. In addition, the Fe3O4 nanoparticles sealed in the kit can well stand long-term storage even for 300 days without deteriorating the colloidal stability and radiolabeling yield. Upon intravenous injection of the as-prepared radiolabeled nanoprobes, high-resolution vascular images of mice were obtained by vascular SPECT imaging and magnetic resonance angiography, demonstrating the promising clinical translational value of our radiolabeling kit.