Red Blood Cell Inspired Strategies for Drug Delivery: Emerging Concepts and New Advances.

In the past five decades, red blood cells (RBCs) have been extensively explored as drug delivery systems due to their distinguishing potential in modulating the pharmacokinetic, pharmacodynamics, and biological activity of carried payloads. The extensive interests in RBC-mediated drug delivery technologies are in part derived from RBCs' unique biological features such as long circulation time, wide access to many tissues in the body, and low immunogenicity. Owing to these outstanding properties, a large body of efforts have led to the development of various RBC-inspired strategies to enable precise drug delivery with enhanced therapeutic efficacy and reduced off-target toxicity. In this review, we discuss emerging concepts and new advances in such RBC-inspired strategies, including native RBCs, ghost RBCs, RBC-mimetic nanoparticles, and RBC-derived extracellular vesicles, for drug delivery.

Selective Fluorescence Imaging of Cancer Cells Based on ROS-Triggered Intracellular Cross-Linking of Artificial Enzyme.

Inside living cells, regulation of catalytic activity of artificial enzymes remains challenging due to issues such as biocompatibility, efficiency, and stability of the catalyst, by which the practical applications of artificial enzymes have been severely hindered. Here, an artificial enzyme, PTT-SGH, with responsiveness to reactive oxygen species (ROS), was obtained by introducing a catalytic histidine residue to pentaerythritol tetra(3-mercaptopropionate) (PTT). The artificial enzyme formed large aggregates in cells via the intracellular ROS-mediated oxidation of thiol groups. The process was significantly facilitated in tumor cells because of the higher ROS concentration in the tumor microenvironment. The catalytic activity of this artificial enzyme was intensively enhanced through deprotonation of cross-linked PTT-SGH, which showed typical esterase activities. Selective fluorescence imaging of tumor cells was achieved using the artificial enzyme to trigger the cleavage of the ester bond of the caged fluorophore inside living cells.

In Situ Synthesis of Photoactive Polymers on a Living Cell Surface via Bio-Palladium Catalysis for Modulating Biological Functions.

Cell surface engineering with functional polymers is an effective strategy to modulate cell activity. Here, a bio-palladium catalyzed polymerization strategy was developed for in situ synthesis of conjugated polymers on living cell surfaces. Through Sonagashira polymerization, photoactive polyphenyleneethynylene (PPE) is synthesized on the cell surface via cell-generated bio-Pd catalyst. The in situ formed PPE is identified by excellent light-harvest capacity and blue fluorescence on the surfaces of E. coli and C. pyrenoidosa. Besides imaging microbes for tracing the polymerization process, PPE also exhibits enhanced antibacterial activity against E. coli. It can also augment the ATP synthesis of C. pyrenoidosa through enlarging the light absorption and accelerating the cyclic electron transport of the algae. With this bio-metal catalyzed polymerization method, functional polymers can be synthesized in situ on the living cell surface.

Supramolecular Strategy Based on Conjugated Polymers for Discrimination of Virus and Pathogens.

A conjugated polymer-based supramolecular system is designed for discrimination of virus and microbes. The supramolecular system is composed of cationic polythiophene derivative (PT) and barrel-shaped macrocyclic molecular cucurbit[7]uril (CB[7]). Because PT and PT/CB[7] complexes possess different interaction manners toward virus and microbes, the rapid and simple discrimination of virus and microbes was realized through polymer fluorescence intensity change assisting with standard linear discriminant analysis (LDA). The supramolecular strategy would expand the idea of designing biological probes and further promote the extensive application of conjugated polymer materials in biosensor field.

Effects of l-tryptophan on the growth, intestinal enzyme activities and non-specific immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress.

In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress, four density groups of sea cucumbers (i.e. 4, 8, 16 and 32 individuals per 40 L water, represented as L, ML, MH and H) were fed with diets containing 0, 1, 3 and 5% l-tryptophan respectively for 75 days. The results showed that the specific growth rates (SGR) of the sea cucumber fed with diet with 3% Trp (L, 2.1; ML, 1.76; MH, 1.2; H, 0.7) were significantly higher than those fed with basal diet without Trp supplementation (P < .05). Peak amylase activity occurred at H stress density at 3% dietary Trp. Trypsin activity was higher in diet 3% in ML and MH densities than the controls, which increased by 66.4% and 53.8%. However, the lipase activity first increased and then decreased from the stocking density L to H, with highest values of 3% Trp group showed the highest value than other groups. Compared to those fed with the basal diet, sea cucumber fed diets with Trp (3%) had significantly higher phagocytic activities (0.28 OD540/106 cells, H) in coelomic fluid and respiratory burst activities (0.105 OD630/106 cells, MH) (P < .05). The results suggested that Trp cannot improve superoxide dismutase (SOD) activity at L, ML and MH densities. The alkaline phosphatase activity (AKP) significantly decreased at H stress density. Under the experimental conditions, the present results confirmed that a diet supplemented with 3% Trp was able to enhance intestinal enzyme activities, non-specific immune response and higher growth performance of A. japonicus.

Neuroprotective effect of deferoxamine on N-methyl-d-aspartate-induced excitotoxicity in RGC-5 cells.

Many N-methyl-d-aspartate (NMDA) receptor antagonists have been used to treat neurodegenerative diseases induced by glutamate excitotoxicity in clinics. However, the universality of the glutamic acid neurotransmitter system makes the glutamic acid receptor blockers inefficient and unsafe. Thus, regulating the downstream signaling pathway in the excitotoxicity of glutamic acid may be a more effective and safer way to antagonize the glutamic acid receptor. In this study, we investigated the effect of deferoxamine (DFO), an iron chelator, on the NMDA-induced excitotoxicity. RGC-5 cells were cultured and identified in vitro, and the NMDA-induced injury was assessed. Then the MTT assay was used to estimate the cell survival and JC-1 staining was performed to detect changes in mitochondrial membrane potential. Immunofluorescent staining and western blot analysis were used to analyze the expressions of respiratory chain proteins. It was found that DFO increased the survival rate of RGC-5 cells and that this effect was positively correlated with the concentration of DFO and the treatment time. The mitochondrial membrane potential and the expression levels of succinate dehydrogenase subunit A and cytochrome c oxidase subunit IV were also increased after DFO treatment, while NMDA reduced their expression levels. These data demonstrate that DFO has significant neuroprotective activity against NMDA-induced excitotoxicity in RGC-5 cells.

Expression of Serum Sialic Acid, Early Antigen-IgA, and Viral Capsid Antigen-IgA in Nasopharynx Cancer Patients: The Diagnostic Implication of Combined Assays.

BACKGROUND Ebstein-Barr virus (EBV) plays a critical role in nasopharynx cancer, which can be effectively monitored by serum levels of early antigen antibody (EA-IgA) and viral capsid antigen antibody (VCA-IgA). This study explored the diagnostic value of combined assays of sialic acid (SA), EA-IgA, and VCA-IgA via the expressional assay. MATERIAL AND METHODS A total of 42 nasopharynx cancer patients and 42 benign rhinitis and healthy controls were recruited in this study. Serum EA-IgA and VCA-IgA were tested by enzyme-linked immunosorbent assay (ELISA) and enzymatic assay of serum SA. Specificity and sensitivity of those 3 assays were compared. The diagnostic value of each parameter was evaluated by ROC curves. RESULTS All 3 indexes (SA, EA-IgA and VCA-IgA) showed elevated serum levels in nasopharynx cancer patients when compared to those with rhinitis, who had higher levels than healthy individuals. Concentrations of these factors were also positively correlated with the TNM staging of cancer. The sensitivity and specificity were 30.95% and 83.33% (in SA), 57.14% and 95.24% (in EA-IgA), and 76.19% and 92.86% (in VCA-IgA), respectively. VCA-IgA had the highest sensitivity among all 3 indexes. The combined assay increased the diagnostic sensitivity to 92.86% without compromising specificity. CONCLUSIONS SA, EA-IgA, and VCA-IgA levels were significantly elevated in nasopharynx patients' serum. The combined assay may have clinical value in diagnosis and monitoring.

Cellular nanovesicles for therapeutic immunomodulation: A perspective on engineering strategies and new advances.

Cellular nanovesicles which are referred to as cell-derived, nanosized lipid bilayer structures, have emerged as a promising platform for regulating immune responses. Owing to their outstanding advantages such as high biocompatibility, prominent structural stability, and high loading capacity, cellular nanovesicles are suitable for delivering various immunomodulatory molecules, such as small molecules, nucleic acids, peptides, and proteins. Immunomodulation induced by cellular nanovesicles has been exploited to modulate immune cell behaviors, which is considered as a novel cell-free immunotherapeutic strategy for the prevention and treatment of diverse diseases. Here we review emerging concepts and new advances in leveraging cellular nanovesicles to activate or suppress immune responses, with the aim to explicate their applications for immunomodulation. We overview the general considerations and principles for the design of engineered cellular nanovesicles with tailored immunomodulatory activities. We also discuss new advances in engineering cellular nanovesicles as immunotherapies for treating major diseases.

Engineering cells for precision drug delivery: New advances, clinical translation, and emerging strategies.

Cells have emerged as a promising new form of drug delivery carriers owing to their distinguished advantages such as naturally bypassing immune recognition, intrinsic capability to navigate biological barriers, and access to hard-to-reach tissues via onboarding sensing and active motility. Over the past two decades, a large body of work has focused on understanding the ability of cell carriers to breach biological barriers and to modulate drug pharmacokinetics and pharmacodynamics. These efforts have led to the engineering of various cells for tissue-specific drug delivery. Despite exciting advances, clinical translation of cell-based drug carriers demands a thorough understanding of the pressing challenges and potential strategies to overcome them. Here, we summarize recent advances and new concepts in cell-based drug carriers and their clinical translation. We also discuss key considerations and emerging strategies to engineering the next-generation cell-based delivery technologies for more precise, targeted drug delivery.

Pathologically high intraocular pressure disturbs normal iron homeostasis and leads to retinal ganglion cell ferroptosis in glaucoma.

Glaucoma can result in retinal ganglion cell (RGC) death and permanently damaged vision. Pathologically high intraocular pressure (ph-IOP) is the leading cause of damaged vision during glaucoma; however, controlling ph-IOP alone does not entirely prevent the loss of glaucomatous RGCs, and the underlying mechanism remains elusive. In this study, we reported an increase in ferric iron in patients with acute primary angle-closure glaucoma (the most typical glaucoma with ph-IOP damage) compared with the average population by analyzing free iron levels in peripheral serum. Thus, iron metabolism might be involved in regulating the injury of RGCs under ph-IOP. In vitro and in vivo studies confirmed that ph-IOP led to abnormal accumulation of ferrous iron in cells and retinas at 1-8 h post-injury and elevation of ferric iron in serum at 8 h post-injury. Nuclear receptor coactivator 4 (NCOA4)-mediated degradation of ferritin heavy polypeptide 1(FTH1) is essential to disrupt iron metabolism in the retina after ph-IOP injury. Furthermore, knockdown of Ncoa4 in vivo inhibited FTH1 degradation and reduced the retinal ferrous iron level. Elevated ferrous iron induced by ph-IOP led to a marked accumulation of pro-ferroptotic factors (lipid peroxidation and acyl CoA synthetase long-chain family member 4) and a depletion of anti-ferroptotic factors (glutathione, glutathione peroxidase 4, and nicotinamide adenine dinucleotide phosphate). These biochemical changes resulted in RGC ferroptosis. Deferiprone can pass through the blood-retinal barrier after oral administration and chelated abnormally elevated ferrous iron in the retina after ph-IOP injury, thus inhibiting RGC ferroptosis and protecting visual function. In conclusion, this study revealed the role of NCOA4-FTH1-mediated disturbance of iron metabolism and ferroptosis in RGCs during glaucoma. We demonstrate the protective effect of Deferiprone on RGCs via inhibition of ferroptosis, providing a research direction to understand and treat glaucoma via the iron homeostasis and ferroptosis pathways.

Regional differences of the sclera in the ocular hypertensive rat model induced by circumlimbal suture.

PURPOSE: To describe the regional differences of the sclera in ocular hypertension (OHT) models with the inappropriate extension of the ocular axis. METHODS: To discover the regional differences of the sclera at the early stage, OHT models were established using circumlimbal suture (CS) or sclerosant injection (SI). Axial length (AL) was measured by ultrasound and magnetic resonance imaging. The glaucoma-associated distinction was determined by intraocular pressure (IOP) and retrograde tracing of retinal ganglion cells (RGCs). The central thickness of the ganglion cell complex (GCC) was measured by optical coherence tomography. RGCs and collagen fibrils were detected using a transmission electron microscope, furthermore, anti-alpha smooth muscle actin (αSMA) was determined in the early stage after the operation. RESULTS: Compared with the control group, the eyes in OHT models showed an increased IOP (P < 0.001 in the CS group, P = 0.001 in the SI group), growing AL (P = 0.026 in the CS group, P = 0.043 in the SI group), reduction of central RGCs (P < 0.001 in the CS group, P = 0.017 in the SI group), thinning central GCC (P < 0.001 in the CS group), and a distinctive expression of αSMA in the central sclera in the early 4-week stage after the operation (P = 0.002 in the CS group). Compared with the SI group, the eye in the CS group showed a significantly increased AL (7.1 ± 0.4 mm, P = 0.031), reduction of central RGCs (2121.1 ± 87.2 cells/mm2, P = 0.001), thinning central GCC (71.4 ± 0.8 pixels, P = 0.015), and a distinctive expression of αSMA (P = 0.005). Additionally, ultrastructural changes in RGCs, scleral collagen fibers, and collagen crimp were observed in the different regions. Increased collagen volume fraction in the posterior segment of the eyeball wall (30.2 ± 3.1%, P = 0.022) was observed by MASSON staining in the CS group. CONCLUSION: Regional differences of the sclera in the ocular hypertensive rat model induced by CS may provide a reference for further treatment of scleral-related eye disorders.

Performance assessment of bubbles barriers for microplastic remediation.

We report the results of experiments designed to evaluate the performance of a bubble barrier device for microplastics collection in natural and artificial streams. Bubble barrier is an innovative device based on the principle that pumping air to produce a vertical curtain of small air bubbles along the depth of a waterway creates a sufficient current to direct floating and non-floating particle towards a catchment device. The bubble barrier has been designed and already tested in rivers. Despite its use, there is a lack of information on the fluid mechanical functioning and performance, i.e., its ability to catch the largest number of microplastic particles. The aim of the present study is to test different bubble barriers configurations (length of the bubble generator, alignment with the main current) in different hydraulic conditions. We used a laboratory channel to produce a scaled river flow and we performed velocity measurements, and particle tracking visualization to understand how the bubble curtain could influence the water flow. The catchment performance of the different barriers has been tested using two types of particles, lighter and heavier than water. The results show that the system performance is strongly linked to a combination of the bubble generator configuration and the main properties of the flow. This study is the first attempt to provide scientific data on the bubble barrier and future design strategies depending on its application.

Evaluation of Macular and Peripapillary Blood Flow in Response to Intraocular Pressure Reduction in Patients With Posner-Schlossman Syndrome.

Purpose: The study aimed to evaluate the effect of intraocular pressure (IOP) reduction on macular and peripapillary microcirculation in patients with Posner-Schlossman syndrome (PSS) by optical coherence tomography angiography (OCTA). Methods: A prospective comparative study was conducted. Patients diagnosed with PSS at the Eye Center of Xiangya Hospital, Central South University, from February 2020 to November 2021 were consecutively included. OCTA was used for the macular and peripapillary microcirculation measurements, and optical coherence tomography (OCT) was employed for the retinal nerve fiber layer (RNFL) and lamina cribrosa depth (LCD) measurements. The patients received OCT and OCTA examinations at baseline and 1 week post-treatment when the IOP was under control. Changes in macular and peripapillary microcirculation, RNFL, and LCD were calculated for all the analyzed areas. Results: Twenty-one eyes from 21 patients were included in the study. Pre-treatment and post-treatment IOP were 43.17 ± 10.36 mm Hg (range, 30-60 mm Hg) and 17.17 ± 2.85 mm Hg (range, 13-23 mm Hg), respectively. No statistically significant changes were detected in RNFL, LCD, or macular and peripapillary microcirculation after significant IOP reduction. Conclusion: The results suggested that a large IOP reduction may not result in a significant increase in peripapillary and macular capillary perfusion in patients with PSS.

Application of team-based learning to ophthalmology in China.

Objectives: The purpose of this study was to explore whether team-based learning (TBL) was more effective than traditional didactic lectures (TDLs) in improving medical students' problem-solving and study skills in the clinical course of ophthalmology. In addition, we were also concerned about Chinese students' satisfaction with TBL. Methods: Our study program involved 275 students of the 5-year clinical medicine program from Central South China University, of which 140 were enrolled in a modified TBL course. A questionnaire that included closed-ended and open-ended items was distributed to students immediately following the completion of the TBL session, and 108 valid questionnaires were collected. Descriptive statistics were used to analyze quantitative data. The effects of the TBL module on students' performance were measured between the groups using a one-way between-group analysis of variance (ANOVA) test by the individual readiness assurance test (IRAT), the group readiness assurance test (GRAT), and final examination scores (FESs), compared with a class without the TBL session. Results: With our modified TBL strategy, 140 students achieved a mean test score of 72.65 on test questions that assessed their knowledge of ophthalmology compared to 135 students who achieved a mean score of 70.8 using the TDL method (p = 0.3434). The performance in a pre-class quiz was significantly better in the GRAT compared to the IRAT. In comparison to the TDL session, the modified TBL was preferred and acceptable by most medical students. Conclusions: By applying the modified TBL to ophthalmology, students improved their performance, self-study, and teamwork, and their class engagement and satisfaction were enhanced. However, TBL should be further optimized and developed to enhance educational outcomes.

Bacteria-Mediated Intracellular Click Reaction for Drug Enrichment and Selective Apoptosis of Drug-Resistant Tumor Cells.

Functionalized biocarriers that can perform bio-orthogonal reactions in tumor cells may provide solutions to overcome the efflux of the chemotherapeutic agent from drug-resistant tumor cells. Herein, we report the enrichment of therapeutic drugs in tumor cells through intracellular click reaction with functionalized bacteria. Specifically, an intracellular bioactive drug enrichment template (OPV@Escherichia coli) is constructed by combining positively charged oligo(phenylene-vinylene)-alkyne (OPV-C≡CH) with E. coli via electrostatic interaction. After the cell uptake of OPV@E. coli and Cu(II)-based complex, Cu(I) generated in situ can catalyze the bio-orthogonal click reaction to covalently anchor the azide-bearing molecules of cyanine 5 (Cy5-N3) and paclitaxel (PTX-N3) on OPV@E. coli. These molecules and their functions were retained and enriched inside the drug-resistant tumor cells A549T, which can label cells with fluorescent probes and selectively induce the apoptosis of drug-resistant tumor cells.

3D printing of artificial skin patches with bioactive and optically active polymer materials for anti-infection and augmenting wound repair.

A printable ink composed of a photoactive cationic conjugated poly(phenylene vinylene) derivative (PPV) and gelatin/alginate/hyaluronic acid is developed for 3D printing artificial skin patches. This patch shows excellent photodynamic therapy-based anti-infection superiority and outstanding bioactivity to facilitate wound repair. This study contributes to design new conjugated polymer inks for manufacturing functional skin patches.

Self-luminescent photodynamic therapy and pathogen detection for infectious diseases.

The importance of detection and treatments of infectious diseases has been stressed to the world by the ongoing COVID-19 pandemic. As a substitution of an external light source, self-luminescent therapeutics featuring in situ light emission aims to address the lack of tissue penetration in conventional photodynamic therapy (PDT). Luminol-based self-luminescent systems are successfully incorporated in PDT and detection of pathogens in infectious diseases. In these systems, luminol/hydrogen peroxide is served as luminescence source which can be activated by horseradish peroxidase (HRP). As a supplement strategy to the HRP-based bioluminescence, electrochemiluminescence (ECL) provided an electric-driven therapeutic solution and demonstrated potential capabilities of wearable healthcare devices with properly constructed transparent flexible hydrogels. Besides the diagnosis of infection and detection of bacteria, fungi and virus in solution or powder samples have been achieved by ATP-derived self-luminescence as the light source. In this inspirational note, we provide an overview on latest progress in the PDT and microbial detection by self-luminescent systems with an emphasis on the bioluminescence and ECL.

Management of the Temporal Bone Fibrous Dysplasia With External Auditory Canal Stenosis and Secondary Cholesteatoma in an Asian Population: A 11-Case Series.

OBJECTIVE: This article summarizes the experience of diagnosis and treatment of temporal bone fibrous dysplasia (FD) with external auditory canal (EAC) stenosis and secondary cholesteatoma in the Chinese population, in order to improve the quality of life of patients in the future. METHODS: Eleven patients with FD of the temporal bone who underwent surgery were retrospectively reviewed. RESULTS: All lesions originated from the temporal bone, and all involved of the EAC. There were 11 cases of cholesteatoma in the EAC, 4 cases of cholesteatoma in the middle ear. The most common symptoms were hearing loss (100%), tinnitus (36.4%), and otorrhea (36.4%). Two patients were severe-profound sensorineural hearing loss, and one patient was complicated with subperiosteal abscesses. All 11 patients underwent surgery. There were no perioperative complications in this series and median follow-up time was 4.2 years. CONCLUSION: Temporal bone FD remains a rare diagnosis, especially in the Asian population. The lesions mainly lead to stenosis of the EAC, especially at the osteochondral junction. Cholesteatoma is the main complication of this disease, which is secondary to occlusion of the EAC with the growth of the lesion. Canaloplasty of EAC combined with wide meatoplasty can provide excellent prognosis in most cases.

Photocontrolled RAFT Polymerization Catalyzed by Conjugated Polymers under Aerobic Aqueous Conditions.

Photocontrolled polymerization offers a convenient way to direct the reaction progress and tailor the polymer structures. Nevertheless, conjugated polymers are yet to be utilized as the photocatalyst in associated reactions. Herein, we employed poly(boron dipyrromethene-alt-fluorene) (PBF), a conjugated polymer with better photostability than eosin Y, as the photocatalyst for photo-RAFT polymerizations of acrylic monomers, and the polymers were obtained with moderately narrow molecular weight distributions. The reaction progress was effectively controlled by switching irradiation conditions, and the block copolymers were prepared from chain extension of a macroinitiator. As electron spin resonance (ESR) and optical spectra results suggested, the reductive quenching of PBF* by ascorbate was the key step leading to the reduction of a chain transfer agent (CTA), whereas the hydroxyl radical derived from superoxide was considered as a byproduct of deoxygenation.

Near-Infrared-Light Remote-Controlled Activation of Cancer Immunotherapy Using Photothermal Conjugated Polymer Nanoparticles.

Remote control of the therapeutic process is an ideal strategy for maximizing efficacy and avoiding side effects, especially for cancer immunotherapy. Herein, a conjugated polymer nanoparticles (CPNs)-mediated optogenetic system for in situ activation of immunotherapy under near-infrared laser irradiation is reported. This system is composed of photothermal CPNs and interferon-gamma (IFN-γ) plasmid driven by heat shock promoter HSP70. The photothermally responsive CPNs serve as a photo-heat nanotransducer to trigger the gene transcription of IFN-γ cytokine. The secreted IFN-γ from cancer cells can sufficiently elicit surrounding tumor-associated macrophages activation through IFN-γ-JAK-STAT1 transcription-factor signaling pathway and finally induce cancer cell killing by immunotherapy. Therefore, this synergetic optogenetic system provides a promising approach to remotely control the process of cancer immunotherapy.