Biomedical polymers: synthesis, properties, and applications

Hydrogels as promising platforms for engineered living bacteria-mediated therapeutic systems

The idea of using engineered bacteria as prospective living therapeutic agents for the treatment of different diseases has been raised. Nevertheless, the development of safe and effective treatment strategies remains essential to the success of living bacteria-mediated therapy. Hydrogels have presented great promise for the delivery of living bacterial therapeutics due to their tunable physicochemical properties, good bioactivities, and excellent protection of labile payloads. In this review, we summarize the hydrogel design strategies for living bacteria-mediated therapy and review the recent advances in hydrogel-based living bacterial agent delivery for the treatment of typical diseases, including those for digestive health, skin fungal infections, wound healing, vaccines, and cancer, and discuss the current challenges and future perspectives of these strategies in the field. It is believed that the importance of hydrogel-based living bacteria-mediated therapy is expected to further increase with the development of both synthetic biology and biomaterials science in the future.

Tumor Antigen Loaded Nanovaccine Induced NIR-Activated Inflammation for Enhanced Antigen Presentation During Immunotherapy of Tumors

Although anticancer vaccines have achieved certain effects in early clinical practice, T cell immunity as the most common responsive pattern of anticancer vaccines is still limited by unsatisfied tumor recognition and inhibition efficiency. As the critical step of T cell immunity, uptake and presentation of specific antigen by antigen-presenting cells (APC) can be activated by inflammation for enhancing the response of T cells to the antigen source. Here, a hybrid nanovaccine named PTh/MnO₂ @M activated with a near-infrared ray (NIR) is prepared by coating an autologous tumor cell membrane on the surface of a polythiophene/MnO₂ composite core. The photoelectrical material polythiophene can produce local microinflammation under NIR radiation and activate specific T cell antitumor immunity by promoting APC maturation and autologous tumor antigens presentation. Moreover, the synthesized nanovaccine PTh/MnO₂ @M is shown to induce a significant antitumor immune response, effectively inhibit the progression of melanoma in mice, and significantly prolong the survival time of mice in vivo. This strategy aims to enhance T-cell immune responses by promoting antigen presentation, leading to effective and specific cancer therapy.

Nanocarrier-based delivery of arsenic trioxide for hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) poses a severe threat to human health and economic development. Despite many attempts at HCC treatment, most are inevitably affected by the genetic instability and variability of tumor cells. Arsenic trioxide (ATO) has shown to be effective in HCC. However, time-consuming challenges, especially the optimal concentration in tumor tissue and bioavailability of ATO, remain to be overcome for its transition from the bench to the bedside. To bypass these issues, nanotechnology-based delivery systems have been developed for prevention, diagnosis, monitoring and treatment in recent years. This article is a systematic overview of the latest contributions and detailed insights into ATO-loaded nanocarriers, with particular attention paid to strategies for improving the efficacy of nanocarriers of ATO.

Targeting to Tumor-Harbored Bacteria for Precision Tumor Therapy

The differential tumor environment guides various antitumor drug delivery strategies for efficient cancer treatment. Here, based on the special bacteria-enriched tumor environment, we report a different drug delivery strategy by targeting bacteria inhabiting tumor sites. With a tissue microarray analysis, it was found that bacteria amounts displayed significant differences between tumor and normal tissues. Bacteria-targeted mesoporous silica nanoparticles decorated with bacterial lipoteichoic acid (LTA) antibody (LTA-MSNs) could precisely target bacteria in tumors and deliver antitumor drugs. By the intravenous administration of bacteria-targeted nanoparticles, we showed in mice with colon cancer, lung cancer, and breast cancer that LTA-MSNs exhibited a high tumor-targeting ability. As a proof-of-concept study, tumor microbes as some of the characteristics of a tumor environment could be utilized as potential targets for tumor targeting. This bacteria-guided tumor-targeting strategy might have great potential in differential drug delivery and cancer treatment.

Lactose azocalixarene drug delivery system for the treatment of multidrug-resistant pseudomonas aeruginosa infected diabetic ulcer

Diabetic wound is one of the most intractable chronic wounds that is prone to bacterial infection. Hypoxia is an important feature in its microenvironment. However, it is challenging for antimicrobial therapy to directly apply the existing hypoxia-responsive drug delivery systems due to the active targeting deficiency and the biofilm obstacle. Herein, we customizes a hypoxia-responsive carrier, lactose-modified azocalix[4]arene (LacAC4A) with the ability to actively target and inhibit biofilm. By loading ciprofloxacin (Cip), the resultant supramolecular nanoformulation Cip@LacAC4A demonstrates enhanced antibacterial efficacy resulting from both the increased drug accumulation and the controlled release at the site of infection. When applied on diabetic wounds together with multidrug-resistant Pseudomonas aeruginosa infection in vivo, Cip@LacAC4A induces definitely less inflammatory infiltration than free Cip, which translates into high wound healing performance. Importantly, such design principle provides a direction for developing antimicrobial drug delivery systems.

Recent progress in nanocomposites of carbon dioxide fixation derived reproducible biomedical polymers

In recent years, the environmental problems accompanying the extensive application of biomedical polymer materials produced from fossil fuels have attracted more and more attentions. As many biomedical polymer products are disposable, their life cycle is relatively short. Most of the used or overdue biomedical polymer products need to be burned after destruction, which increases the emission of carbon dioxide (CO₂). Developing biomedical products based on CO₂ fixation derived polymers with reproducible sources, and gradually replacing their unsustainable fossil-based counterparts, will promote the recycling of CO₂ in this field and do good to control the greenhouse effect. Unfortunately, most of the existing polymer materials from renewable raw materials have some property shortages, which make them unable to meet the gradually improved quality and property requirements of biomedical products. In order to overcome these shortages, much time and effort has been dedicated to applying nanotechnology in this field. The present paper reviews recent advances in nanocomposites of CO₂ fixation derived reproducible polymers for biomedical applications, and several promising strategies for further research directions in this field are highlighted.

Mechano-bioconjugation Strategy Empowering Fusion Protein Therapeutics with Aggregation Resistance, Prolonged Circulation, and Enhanced Antitumor Efficacy

Bioconjugation is a powerful protein modification strategy to improve protein properties. Herein, we report mechano-bioconjugation as a novel approach to empower fusion protein therapeutics and demonstrate its utility by a protein heterocatenane (cat-IFN-ABD) containing interferon-α2b (IFN) mechanically interlocked with a consensus albumin-binding domain (ABD). The conjugate was selectively synthesized in cellulo following a cascade of post-translational events using a pair of heterodimerizing p53dim variants and two orthogonal split-intein reactions. The catenane topology was proven by combined techniques of LC-MS, SDS-PAGE, SEC, and controlled proteolytic digestion. Not only did cat-IFN-ABD retain activities comparable to those of the wild-type IFN and ABD, the conjugate also exhibited enhanced aggregation resistance and prolonged circulation time over the simple linear and cyclic fusions. Consequently, cat-IFN-ABD potently inhibited tumor growth in the mouse xenograft model. Therefore, mechano-bioconjugation by catenation accomplishes function integration with additional benefits, providing an alternative pathway for developing advanced protein therapeutics.

IL-11Rα-targeted nanostrategy empowers chemotherapy of relapsed and patient-derived osteosarcoma

Osteosarcoma (OS) is a rare but frequently lethal bone malignancy in children and adolescents. The adjuvant chemotherapy with doxorubicin (Dox) and cisplatin remains a mainstream clinical practice though it affords only limited clinical benefits due to low tumor deposition, dose-limiting toxicity and high rate of relapse/metastasis. Here, taking advantage of high IL-11Rα expression in the OS patients, we installed IL-11Rα specific peptide (sequence: CGRRAGGSC) onto redox-responsive polymersomes encapsulating Dox (IL11-PDox) to boost the specificity and anti-OS efficacy of chemotherapy. Of note, IL-11Rα peptide at a density of 20% greatly augmented the internalization, apoptotic activity, and migration inhibition of Dox in IL-11Rα-overexpressing 143B OS cells. The active targeting effect of IL-11-PDox was supported in orthotopic and relapsed 143B OS models, as shown by striking repression of tumor growth and lung metastasis and substantial survival benefits over free Dox control. We further verified that IL11-PDox could effectively inhibit patient-derived OS xenografts. IL-11Rα-targeted nanodelivery of chemotherapeutics provides a potential therapeutic strategy for advanced osteosarcoma.

Drug in Drug: A Host-Guest Formulation of Azocalixarene with Hydroxychloroquine for Synergistic Anti-Inflammation

Macrocyclic delivery and therapeutics are two significant topics in supramolecular biomedicine. The functional integration of these topics would open new avenues for treating diseases synergistically. However, these two individual topics have only been occasionally merged, probably because of the lack of functionalized design of macrocyclic host and the lack of efficient recognition between host and guest drugs. Herein, a "drug-in-drug" strategy is proposed, in which an active drug is encapsulated by a macrocycle possessing therapeutic activity to form a multifunctional supramolecular active pharmaceutical ingredient. As a proof-of-concept, a complex of hydroxychloroquine (HCQ) with sulfonated azocalix[4]arene (HCQ@SAC4A) is prepared to treat rheumatoid arthritis (RA) in a combined fashion. SAC4A is a therapeutic agent that exhibits scavenging capacity for reactive oxygen species and exerts an anti-inflammatory effect. It is also a hypoxia-responsive carrier that can deliver HCQ directly to the inflammatory articular cavity. Consequently, HCQ@SAC4A achieves the synergistic anti-inflammatory effect on both inflamed RAW 264.7 cells and RA rats. This effect is attributed to the temporal and spatial consistency of the two active ingredients of the complex. As a new paradigm for combinational therapy, the drug-in-drug strategy advances in easy preparation, mix-and-match combination, and precise ratiometric control.

Sustained release of chlorogenic acid-loaded nanomicelles alleviates bone loss in mouse periodontitis

Abstract Periodontitis is a prevalent chronic inflammatory disease that destroys the periodontal supporting tissues, impinges on oral health, and is correlative with an increased risk of systemic disease. Currently, the...