Dual pH-Responsive Shell-Cleavable Polycarbonate Micellar Nanoparticles for in Vivo Anticancer Drug Delivery

Polymeric micellar nanoparticles for effective CRISPR/Cas9 genome editing in cancer

The clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (Cas9) gene editing has attracted extensive attentions in various fields, however, its clinical application is hindered by the lack of effective and safe delivery system. Herein, we reported a cationic micelle nanoparticle composed of cholesterol-modified branched small molecular PEI (PEI-CHO) and biodegradable PEG-b-polycarbonate block copolymer (PEG-PC), denoted as PEG-PC/PEI-CHO/pCas9, for the CRISPR/Cas9 delivery to realize genomic editing in cancer. Specifically, PEI-CHO condensed pCas9 into nanocomplexes, which were further encapsulated into PEG-PC nanoparticles (PEG-PC/PEI-CHO/pCas9). PEG-PC/PEI-CHO/pCas9 had a PEG shell, protecting DNA from degradation by nucleases. Enhanced cellular uptake of PEG-PC/PEI-CHO/pCas9 nanoparticles was observed as compared to that mediated by Lipo2k/pCas9 nanoparticles, thus leading to significantly elevated transfection efficiency after escaping from endosomes via the proton sponge effect of PEI. In addition, the presence of PEG shell greatly improved biocompatibility, and significantly enhanced the in vivo tumor retention of pCas9 compared to PEI-CHO/pCas9. Notably, apparent downregulation of GFP expression could be achieved both in vitro and in vivo by using PEG-PC/PEI-CHO/pCas9-sgGFP nanoparticles. Furthermore, PEG-PC/PEI-CHO/pCas9-sgMcl1 induced effective apoptosis and tumor suppression in a HeLa tumor xenograft mouse model by downregulating Mcl1 expression. This work may provide an alternative paradigm for the efficient and safe genome editing in cancer.

Reconciling the Cooperative-Competitive Patterns among Tumor and Immune Cells for Triple-Negative Breast Cancer Treatment Using Multimodule Nanocomplexes

Targeting the competitive-cooperative relationships among tumor cells and various immune cells can efficiently reverse the immune-dysfunction microenvironment to boost the immunotherapies for the triple-negative breast cancer treatment. Hence, a bacterial outer membrane vesicle-based nanocomplex is designed for specifically targeting malignant cells and immune cells to reconcile the relationships based on metabolic-immune crosstalk. By uniquely utilizing the property of charge-reversal polymers to realize function separation, the nanocomplexes could synergistically regulate tumor cells and immune cells. This approach could reshape the immunosuppressive competition-cooperation pattern into one that is immune-responsive, showcasing significant potential for inducing tumor remission in TNBC models.

pH-Responsive Polymeric Micelle Dynamic Complexes for Selective Killing of Helicobacter pylori

Helicobacter pylori, the world's most common chronic infection-causing pathogen, is responsible for causing gastric ulcers, the fourth-leading cause of cancer-related death globally in 2020. In recent years, the effectiveness of the current treatment regimen (two antibiotics and one proton pump inhibitor) has often been plagued with problems such as resistance and the undesired elimination of commensal bacteria. Herein, we report the synthesis of block and random copolycarbonates, functionalized with cationic guanidinium and anionic acetate functional groups, aimed at selectively killing H. pylori in the acidic environment of the stomach, while remaining nontoxic to the commensal bacteria in the gut. The compositions of the polymers were fine-tuned so that the polymers were readily dispersed in water without any difficulty at both pH 3.0 and 7.4. The self-assembly behavior of the polymers at different pH values by dynamic light scattering showed that the random and block copolymers formed stable micelles in a simulated gastric environment (pH 3.0) while aggregated at pH 7.4. Both polymers demonstrated stronger antibacterial activity against H. pylori than the guanidinium-functionalized homopolymer without any acetate functional group at pH 3.0. The block copolymer was significantly more bactericidal at pH 3.0 across the concentrations tested, as compared to the random copolymer, while it did not show significant toxicity toward rat red blood cells (rRBCs) and HK-2 cells or bactericidal effect toward E. coli (a common gut bacterium) and nor caused aggregation of rRBCs at its effective concentration and at physiological pH of 7.4. Additionally, both the block and random copolymers were much more stable against hydrolysis at pH 3.0 than at pH 7.4. This study provides insight into the influence of both polymer architecture and dynamic assembly on the bioactivities of antimicrobial polymers, where the disassembly of coacervates into narrowly dispersed micelles at pH 3 make them potent antimicrobials aided by the protonated carboxylic acid block.

Investigating the complexation propensity of self-assembling dipeptides with the anticancer peptide-drug Bortezomib: a computational study

The investigation of potential self-assembled peptides as carriers for the delivery of anticancer drug Bortezomib is the topic of the present study. The self-assembly of Bortezomib in water is examined using all-atom molecular dynamics simulations and corresponding experimental results from FESEM experiments. In addition, a series of dipeptides with a similar chemical formula to Bortezomib with hydrogel-forming ability are being investigated for their propensity to bind to the drug molecule. Dipeptides are divided into two classes, the protected FF (Fmoc-FF and Z-FF) and the LF-based (Cyclo-LF and LF) ones. The thermodynamic stability of the complexes formed in an aqueous environment, as well as key morphological features of the nanoassemblies are investigated at the molecular level. Binding enthalpy between Bortezomib and dipeptides follows the increasing order: LF < Cyclo-LF < Fmoc-FF < Z-FF under both van der Waals and electrostatic contributions. Protected FF dipeptides have a higher affinity for the drug molecule, which will favor its entrapment, giving them an edge over the LF based dipeptides. By evaluating the various measures, regarding both the binding between the two components and the eventual ability of controlled drug release, we conclude that the protected FF class is a more suitable candidate for drug release of Bortezomib, whereas among its two members, Fmoc-FF appears to be more promising. The selection of the optimal candidates based on the present computational study will be a stepping stone for future detailed experimental studies involving the encapsulation and controlled release of Bortezomib both in vitro and in vivo.

Multi-Stimuli-Responsive Nanoparticles Formed of POSS-PEG for the Delivery of Boronic Acid-Containing Therapeutics

Polymeric vehicles often exhibit batch-to-batch variations due to polydispersity, limiting their reproducibility for biomedical applications. In contrast, polyhedral oligomeric silsesquioxane (POSS) has emerged as an attractive candidate for drug delivery due to its precise chemical structure and rigid molecular shape. A promising strategy to enhance drug efficacy while reducing systemic toxicity is the development of multi-stimuli-responsive delivery systems capable of targeted drug release at a disease site. Herein, we developed a drug delivery platform based on POSS-polymer conjugates. By functionalizing the POSS with amino groups and establishing B-N coordination with boronic acids, the nanoparticles (NPs) exhibit responsive behavior to stimuli, including adenosine-5'-triphosphate (ATP), acidic pH, and nucleophilic reagents. We successfully encapsulated two boronic acid-containing molecules: tetraphenylethylene (TPE), serving as a fluorescent probe, and bortezomib (BTZ), an anticancer drug. The TPE@NPs were employed to visualize the cellular uptake of NPs by tumor cells, while the BTZ@NPs exhibited increased cytotoxicity in tumor cells compared with normal cells. This POSS-PEG conjugate offers a nanoparticle platform for encapsulating versatile boronic acid-containing molecules, thereby enhancing drug efficacy while minimizing systemic toxicity. Given the wide-ranging applications of boronic acid-containing molecules in biomedicine, our platform holds significant promise for the development of intelligent drug delivery systems for diagnostics and therapeutics.

Nanocarrier-based targeting of metabolic pathways for endometrial cancer: Status and future perspectives

Cancer is the second-most lethal global disease, as per health reports, and is responsible for around 70% of deaths in low- and middle-income countries. Endometrial cancer is one of the emerging malignancies and has been predicted as a public health challenge for the future. Insulin resistance, obesity, and diabetes mellitus are the key metabolic factors that promote risks for the development of endometrial cancer. Various signaling pathways and associated genes are involved in the genesis of endometrial cancer, and any mutation or deletion in such related factors leads to the induction of endometrial cancer. The conventional way of drug delivery has been used for ages but is associated with poor management of cancer due to non-targeting of the endometrial cancer cells, low efficacy of the therapy, and toxicity issues as well. In this context, nanocarrier-based therapy for the management of endometrial cancer is an effective alternate choice that overcomes the problems associated with conventional therapy. In this review article, we highlighted the nanocarrier-based targeting of endometrial cancer, with a special focus on targeting various metabolic signaling pathways. Furthermore, the future perspectives of nanocarrier-based targeting of metabolic pathways in endometrial cancer were also underpinned. It is concluded that targeting metabolic signaling pathways in endometrial cancer via nanocarrier scaffolds is the future of pharmaceutical design for the significant management and treatment of endometrial cancer.

Sialic Acid Engineered Prodrug Nanoparticles for Codelivery of Bortezomib and Selenium in Tumor Bearing Mice

Most cancer patients rarely benefit from monodrug therapy because of both cancer complexity and tumor environment. One of the main reasons for this failure is insufficient accumulation of the optimal dose at the tumorous site. Our investigation implies a promising strategy to engineer prodrug nanoparticles (NPs) of bortezomib (BTZ) and selenium (Se) using sialic acid (SAL) as a ligand to improve breast cancer therapy. BTZ was conjugated with SAL and HPMA (N-2-hydroxypropyl methacrylamide) to prepare a prodrug conjugate; BTZ-SAL-HPMA (BSAL-HP) and then fabricated into prodrug NPs with Se (Se_BSAL-HP prodrug NPs). The self-assembly of prodrug NPs functionalized with Se showed size (204.13 ± 0.02 nm) and zeta potential (-31.0 ± 0.11 mV) in dynamic light scattering (DLS) experiments and spherical shape in TEM and SEM analysis. Good stability and low pH drug release profile were characterized by Se_BSAL-HP prodrug NPs. The tumor-selective boronate-ester-based prodrug NPs of BTZ in combination with Se endowed a synergistic effect against cancer cells. Compared to prodrug conjugate, Se_BSAL-HP prodrug NPs exhibited higher cell cytotoxicity and enhanced cellular internalization with significant changes in mitochondria membrane potential (MMP). Elevated apoptosis was observed in the (G2/M) phase of the cell cycle for Se_BSAL-HP prodrug NPs (2.7-fold) higher than BTZ. In vivo studies were performed on Sprague-Dawley rats and resulted in positive trends. The increased therapeutic activity of Se_BSAL-HP prodrug NPs inhibited primary tumor growth and showed 43.05 fold decrease in tumor volume than the control in 4T1 tumor bearing mice. The surprising and remarkable outcomes for Se_BSAL-HP prodrug NPs were probably due to the ROS triggering effect of boronate ester and selenium given together.

Research Progress on Stimulus-Responsive Polymer Nanocarriers for Cancer Treatment

As drug carriers for cancer treatment, stimulus-responsive polymer nanomaterials are a major research focus. These nanocarriers respond to specific stimulus signals (e.g., pH, redox, hypoxia, enzymes, temperature, and light) to precisely control drug release, thereby improving drug uptake rates in cancer cells and reducing drug damage to normal cells. Therefore, we reviewed the research progress in the past 6 years and the mechanisms underpinning single and multiple stimulus-responsive polymer nanocarriers in tumour therapy. The advantages and disadvantages of various stimulus-responsive polymeric nanomaterials are summarised, and the future outlook is provided to provide a scientific and theoretical rationale for further research, development, and utilisation of stimulus-responsive nanocarriers.

Efficient pH-Responsive Nano-Drug Delivery System Based on Dynamic Boronic Acid/Ester Transformation

Chemotherapy is currently one of the most widely used treatments for cancer. However, traditional chemotherapy drugs normally have poor tumor selectivity, leading to insufficient accumulation at the tumor site and high systemic cytotoxicity. To address this issue, we designed and prepared a boronic acid/ester-based pH-responsive nano-drug delivery system that targets the acidic microenvironment of tumors. We synthesized hydrophobic polyesters with multiple pendent phenylboronic acid groups (PBA-PAL) and hydrophilic PEGs terminated with dopamine (mPEG-DA). These two types of polymers formed amphiphilic structures through phenylboronic ester linkages, which self-assembled to form stable PTX-loaded nanoparticles (PTX/PBA NPs) using the nanoprecipitation method. The resulting PTX/PBA NPs demonstrated excellent drug encapsulation efficiency and pH-triggered drug-release capacity. In vitro and in vivo evaluations of the anticancer activity of PTX/PBA NPs showed that they improved the pharmacokinetics of drugs and exhibited high anticancer activity while with low systemic toxicity. This novel phenylboronic acid/ester-based pH-responsive nano-drug delivery system can enhance the therapeutic effect of anticancer drugs and may have high potential for clinical transformations.

Stimuli-Responsive Triblock Terpolymer Conversion into Multi-Stimuli-Responsive Micelles with Dynamic Covalent Bonds for Drug Delivery through a Quick and Controllable Post-Polymerization Reaction

Stimuli-responsive copolymers are of great interest for targeted drug delivery. This study reports on a controllable post-polymerization quaternization with 2-bromomethyl-4-fluorophenylboronic acid of the poly(4-vinyl pyridine) (P4VP) block of a common poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) (SVE) triblock terpolymer in order to achieve a selective responsivity to various diols. For this purpose, a reproducible method was established for P4VP block quaternization at a defined ratio, confirming the reaction yield by ¹¹B, ¹H NMR. Then, a reproducible self-assembly protocol is designed for preparing stable micelles from functionalized stimuli-responsive triblock terpolymers, which are characterized by light scattering and by cryogenic transmission electron microscopy. In addition, UV-Vis spectroscopy is used to monitor the boron-ester bonding and hydrolysis with alizarin as a model drug and to study encapsulation and release of this drug, induced by sensing with three geminal diols: fructose, galactose and ascorbic acid. The obtained results show that only the latter, with the vicinal diol group on sp²-hybridized carbons, was efficient for alizarin release. Therefore, the post-polymerization method for triblock terpolymer functionalization presented in this study allows for preparation of specific stimuli-responsive systems with a high potential for targeted drug delivery, especially for cancer treatment.

Metal-phenolic networks with ferroptosis to deliver NIR-responsive CO for synergistic therapy

As an endogenous gasotransmitter, CO has achieved tremendous advances in cancer treatment through selectively killing cancer cells. However, the application of CO in tumor immunotherapy has not been reported and the tumor targeting delivery is still a tremendous challenge. Herein, thermosensitive boronic acid group-containing CO prodrug was synthesized and fabricated with tannic acid (TA) and iron (Fe) to form metal-phenolic networks, and then loaded with near-infrared (NIR) photothermal agent IR820 to form FeCO-IR820@Fe^IIITA for combinational therapy of CO and photothermal therapy. Ferroptosis can also be enhanced due to the Fe³⁺ incorporation. After TA reduced Fe³⁺ into Fe²⁺, Fe²⁺ might lead to intracellular Fenton reaction. Furthermore, in combination with CTLA-4 blockade immunotherapy, FeCO-IR820@Fe^IIITA remarkably inhibited breast tumor growth, suppressed the lung metastasis and improved the antitumor immune response. To summarize, FeCO-IR820@Fe^IIITA provides a potential novel option for CO/photothermal/immune synergistic therapy with enhanced ferroptosis through simple compositions and facile synthesis process.

Targeted therapy of atherosclerosis by pH-sensitive hyaluronic acid nanoparticles co-delivering all-trans retinal and rapamycin

Atherosclerosis, the leading cause of death in the elderly worldwide, is typically characterized by elevated reactive oxygen species (ROS) levels and a chronic inflammatory state at the arterial plaques. Herein, pH-sensitive nanoparticles (HR_RAP NPs) co-delivering all-trans retinal (ATR), an antioxidant linked to hyaluronic acid (HA) through a pH-sensitive hydrazone bond, and rapamycin (RAP), an anti-atherosclerotic drug loaded into the nanoparticle core, are developed for targeted combination therapy of atherosclerosis. In this way, HR_RAP NPs might simultaneously reduce ROS levels via ATR antioxidant activity and reduce inflammation via the anti-inflammatory effect of RAP. In response to mildly acidic conditions mimicking the lesional inflammation in vitro, HR_RAP NPs dissociated and both ATR and RAP were effectively released. The developed HR_RAP NPs effectively inhibited pro-inflammatory macrophage proliferation, and displayed dose- and time-dependent specific internalization by different cellular models of atherosclerosis. Also, HR_RAP NP combination therapy showed an efficient synergetic anti-atherosclerotic effect in vitro by effectively inhibiting the inflammatory response and oxidative stress in inflammatory cells. More importantly, HR NPs specifically accumulated in the atherosclerotic plaques of apolipoprotein E-deficient (ApoE^-/-) mice, by active interaction with HA receptors overexpressed by different cells of the plaque. The treatment with HR_RAP NPs remarkably inhibited the progression of atherosclerosis in ApoE^-/- mice which resulted in stable plaques with considerably smaller necrotic cores, lower matrix metalloproteinase-9, and decreased proliferation of macrophages and smooth muscle cells (SMCs). Furthermore, HR_RAP NPs attenuated RAP adverse effects and exhibited a good safety profile after long-term treatment in mice. Consequently, the developed pH-sensitive HR_RAP NP represent a promising nanoplatform for atherosclerosis combination therapy.

Metal Ion-Directed Functional Metal-Phenolic Materials

Metal ions are ubiquitous in nature and play significant roles in assembling functional materials in fields spanning chemistry, biology, and materials science. Metal-phenolic materials are assembled from phenolic components in the presence of metal ions through the formation of metal-organic complexes. Alkali, alkali-earth, transition, and noble metal ions as well as metalloids interacting with phenolic building blocks have been widely exploited to generate diverse hybrid materials. Despite extensive studies on the synthesis of metal-phenolic materials, a comprehensive summary of how metal ions guide the assembly of phenolic compounds is lacking. A fundamental understanding of the roles of metal ions in metal-phenolic materials engineering will facilitate the assembly of materials with specific and functional properties. In this review, we focus on the diversity and function of metal ions in metal-phenolic material engineering and emerging applications. Specifically, we discuss the range of underlying interactions, including (i) cation-π, (ii) coordination, (iii) redox, and (iv) dynamic covalent interactions, and highlight the wide range of material properties resulting from these interactions. Applications (e.g., biological, catalytic, and environmental) and perspectives of metal-phenolic materials are also highlighted.

Targeted Cancer Therapy via pH-Functionalized Nanoparticles: A Scoping Review of Methods and Outcomes

(1) Background: In recent years, several studies have described various and heterogenous methods to sensitize nanoparticles (NPs) to pH changes; therefore, in this current scoping review, we aimed to map current protocols for pH functionalization of NPs and analyze the outcomes of drug-loaded pH-functionalized NPs (pH-NPs) when delivered in vivo in tumoral tissue. (2) Methods: A systematic search of the PubMed database was performed for all published studies relating to in vivo models of anti-tumor drug delivery via pH-responsive NPs. Data on the type of NPs, the pH sensitization method, the in vivo model, the tumor cell line, the type and name of drug for targeted therapy, the type of in vivo imaging, and the method of delivery and outcomes were extracted in a separate database. (3) Results: One hundred and twenty eligible manuscripts were included. Interestingly, 45.8% of studies (n = 55) used polymers to construct nanoparticles, while others used other types, i.e., mesoporous silica (n = 15), metal (n = 8), lipids (n = 12), etc. The mean acidic pH value used in the current literature is 5.7. When exposed to in vitro acidic environment, without exception, pH-NPs released drugs inversely proportional to the pH value. pH-NPs showed an increase in tumor regression compared to controls, suggesting better targeted drug release. (4) Conclusions: pH-NPs were shown to improve drug delivery and enhance antitumoral effects in various experimental malignant cell lines.

Simple and Efficient Synthesis of Functionalized Cyclic Carbonate Monomers Using Carbon Dioxide

Aliphatic polycarbonates represent an important class of materials with diverse applications ranging from battery electrolytes, polyurethane intermediates, and materials for biomedical applications. These materials can be produced via the ring-opening polymerization (ROP) of six- to eight-membered cyclic carbonates derived from precursor 1,3- and 1,5-diols. These diols can contain a range of functional groups depending on the desired thermal, mechanical, and solution properties. Generally, the ring closure to form the cyclic carbonate requires the use of undesirable and hazardous reagents. Advances in synthetic methodologies and catalysis have enabled the use of carbon dioxide (CO₂) to perform these transformations with a high conversion of diol to cyclic carbonate, yet modest isolated yields due to oligomerization side reactions. In this Letter, we evaluate a series of bases in the presence of p-toluenesulfonyl chloride and the appropriate diol to better understand their effect on the yield and presence of oligomer byproducts during cyclic carbonate formation from CO₂. From this study, N,N-tetramethylethylenediamine (TMEDA) was identified as an optimal base, facilitating the preparation of a diverse array of both six- and eight-membered carbonates from CO₂ within 10 to 15 min. The robust conditions for both, the preparation of the diol precursor, and the TMEDA-mediated carbonate synthesis enabled readily telescoping the two-step reaction sequence, greatly simplifying the process of monomer preparation.

Biodegradable Ru-Containing Polycarbonate Micelles for Photoinduced Anticancer Multitherapeutic Agent Delivery and Phototherapy Enhancement

The lack of selectivity between tumor and healthy cells, along with inefficient reactive oxygen species production in solid tumors, are two major impediments to the development of anticancer Ru complexes. The development of photoinduced combination therapy based on biodegradable polymers that can be light activated in the "therapeutic window" would be beneficial for enhancing the therapeutic efficacy of Ru complexes. Herein, a biodegradable Ru-containing polymer (poly(DCARu)) is developed, in which two different therapeutics (the drug and the Ru complex) are rationally integrated and then conjugated to a diblock copolymer (MPEG-b-PMCC) containing hydrophilic poly(ethylene glycol) and cyano-functionalized polycarbonate with good degradability and biocompatibility. The polymer self-assembles into micelles with high drug loading capacity, which can be efficiently internalized into tumor cells. Red light induces the generation of singlet oxygen and the release of anticancer drug-Ru complex conjugates from poly(DCARu) micelles, hence inhibiting tumor cell growth. Furthermore, the phototherapy of polymer micelles demonstrates remarkable inhibition of tumor growth in vivo. Meanwhile, polymer micelles exhibit good biocompatibility with blood and healthy tissues, which opens up opportunities for multitherapeutic agent delivery and enhanced phototherapy.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Design of Smart Size-, Surface-, and Shape-Switching Nanoparticles to Improve Therapeutic Efficacy

Multiple biological barriers must be considered in the design of nanomedicines, including prolonged blood circulation, efficient accumulation at the target site, effective penetration into the target tissue, selective uptake of the nanoparticles into target cells, and successful endosomal escape. However, different particle sizes, surface chemistries, and sometimes shapes are required to achieve the desired transport properties at each step of the delivery process. In response, this review highlights recent developments in the design of switchable nanoparticles whose size, surface chemistry, shape, or a combination thereof can be altered as a function of time, a disease-specific microenvironment, and/or via an externally applied stimulus to enable improved optimization of nanoparticle properties in each step of the delivery process. The practical use of such nanoparticles in chemotherapy, bioimaging, photothermal therapy, and other applications is also discussed.

Shell-Sheddable Micelles Based on Poly(ethylene glycol)-hydrazone-poly[R,S]-3-hydroxybutyrate Copolymer Loaded with 8-Hydroxyquinoline Glycoconjugates as a Dual Tumor-Targeting Drug Delivery System

The development of selective delivery of anticancer drugs into tumor tissues to avoid systemic toxicity is a crucial challenge in cancer therapy. In this context, we evaluated the efficacy of a combination of nanocarrier pH-sensitivity and glycoconjugation of encapsulated drugs, since both vectors take advantage of the tumor-specific Warburg effect. Herein, we synthesized biodegradable diblock copolymer, a poly(ethylene glycol)-hydrazone linkage-poly[R,S]-3-hydroxybutyrate, which could further self-assemble into micelles with a diameter of ~55 nm. The hydrazone bond was incorporated between two copolymer blocks under an acidic pH, causing the shell-shedding of micelles which results in the drug's release. The micelles were stable at pH 7.4, but decompose in acidic pH, as stated by DLS studies. The copolymer was used as a nanocarrier for 8-hydroxyquinoline glucose and galactose conjugates as well as doxorubicin, and exhibited pH-dependent drug release behavior. In vitro cytotoxicity, apoptosis, and life cycle assays studies of blank and drug-loaded micelles were performed on Normal Human Dermal Fibroblasts-Neonatal (NHDF-Neo), colon carcinoma (HCT-116), and breast cancer (MCF-7) for 24, 48, and 72 h. A lack of toxicity of blank micelles was demonstrated, whereas the glycoconjugates-loaded micelles revealed enhanced selectivity to inhibit the proliferation of cancer cells. The strategy of combining pH-responsive nanocarriers with glycoconjugation of the drug molecule provides an alternative to the modus operandi of designing multi-stimuli nanocarriers to increase the selectivity of anticancer therapy.

Progress on the Application of Bortezomib and Bortezomib-Based Nanoformulations

Bortezomib (BTZ) is the first proteasome inhibitor approved by the Food and Drug Administration. It can bind to the amino acid residues of the 26S proteasome, thereby causing the death of tumor cells. BTZ plays an irreplaceable role in the treatment of mantle cell lymphoma and multiple myeloma. Moreover, its use in the treatment of other hematological cancers and solid tumors has been investigated in numerous clinical trials and preclinical studies. Nevertheless, the applications of BTZ are limited due to its insufficient specificity, poor permeability, and low bioavailability. Therefore, in recent years, different BTZ-based drug delivery systems have been evaluated. In this review, we firstly discussed the functions of proteasome inhibitors and their mechanisms of action. Secondly, the properties of BTZ, as well as recent advances in both clinical and preclinical research, were reviewed. Finally, progress in research regarding BTZ-based nanoformulations was summarized.

Hierarchical dual-responsive cleavable nanosystem for synergetic photodynamic/photothermal therapy against melanoma

Currently, the combining photodynamic therapy (PDT) with photothermal therapy (PTT) modalities based on a single near infrared (NIR) laser irradiation and highly selective internalization still remain a challenge. Herein, a hierarchical dual-responsive cleavable nanosystem for synergetic NIR triggered PDT/PTT is reported. The engineered nanoplatform (Au NRs/Cur/UCNPs@PBE) is designed by loading curcumin (Cur, photosensitizer) on gold nanarods (Au NRs) to build PDT/PTT therapy system, which was encapsulated outside with upconversion nanoparticles (UCNPs) and then modified with phenylboronic double ester (PBE). The pH and ROS-responsive feature made Au NRs/Cur/UCNPs@PBE provide a fundamental structural evolution and improve the specificity and intracellular accumulation to tumors. Au NRs/Cur/UCNPs@PBE exhibited significant PDT and PTT efficiency against two type melanoma cells due to upconversion nanoparticles and Au NRs induced by an 808 nm laser. Notably, the platform can mainly activate apoptosis and partial ferroptosis to achieve the synergistic PDT/PTT, furthermore, the integrated PDT with PTT using Au NRs/Cur/UCNPs@PBE showcased a great antitumor efficacy in vivo superior to the other alone treatment. Our findings highlight that this intelligent nanoagents for synergistic phototherapy facilitate enhanced fighting melanoma and provide a promising strategy for melanoma theranostics.

Multifunctional Polymeric Nanogels for Biomedical Applications

Currently, research in nanoparticles as a drug delivery system has broadened to include their use as a delivery system for bioactive substances and a diagnostic or theranostic system. Nanogels, nanoparticles containing a high amount of water, have gained attention due to their advantages of colloidal stability, core-shell structure, and adjustable structural components. These advantages provide the potential to design and fabricate multifunctional nanosystems for various biomedical applications. Modified or functionalized polymers and some metals are components that markedly enhance the features of the nanogels, such as tunable amphiphilicity, biocompatibility, stimuli-responsiveness, or sensing moieties, leading to specificity, stability, and tracking abilities. Here, we review the diverse designs of core-shell structure nanogels along with studies on the fabrication and demonstration of the responsiveness of nanogels to different stimuli, temperature, pH, reductive environment, or radiation. Furthermore, additional biomedical applications are presented to illustrate the versatility of the nanogels.

Indocyanine green loaded pH-responsive bortezomib supramolecular hydrogel for synergistic chemo-photothermal/photodynamic colorectal cancer therapy

Colorectal cancer is with high incidence worlwide.. Because of the heterogeneity of the tumor, combination therapy is probably of great significance to improve the prognosis of colorectal cancer patients. Herein, the pH-responsive supramolecular hydrogels mPEG-luteolin-BTZ@ICG based on bortezomib (BTZ) and indocyanine green (ICG) were prepared, and the colorectal cancer was treated with mPEG-luteolin-BTZ@ICG through the combination of photothermal/photodynamic and chemotherapy. BTZ performed drug therapy, meanwhile ICG wrapped in supramolecular hydrogels possessed higher light stability than free ICG to perform photothermal/photodynamic therapy. In vitro and in vivo assays showed excellent inhibition of tumor cells due to the combined effect of BTZ and ICG. The mPEG-luteolin-BTZ@ICG combined with laser therapy possessed exceptional biological safety and provided new candidates for advanced colon cancer therapy and important references for other tumor therapies.

Use of pH-Active Catechol-Bearing Polymeric Nanogels with Glutathione-Responsive Dissociation to Codeliver Bortezomib and Doxorubicin for the Synergistic Therapy of Cancer

Synergistic therapy holds promising potential in cancer treatment. Here, the inclusion of catechol moieties, a disulfide cross-linked structure, and pendent carboxyl into the network of polymeric nanogels with glutathione (GSH)-responsive dissociation and pH-sensitive release is first disclosed for the codelivery of doxorubicin (DOX) and bortezomib (BTZ) in synergistic cancer therapy. The pendent carboxyl groups and catechol moieties are exploited to absorb DOX through electrostatic interaction and conjugate BTZ through boronate ester, respectively. Both electrostatic interactions and boronate ester are stable at neutral or alkaline pH, while they are instable in an acidic environment to further recover the activities of BTZ and DOX. The polymeric nanogels possess a superior stability to prevent the premature leakage of drugs in a physiological environment, while their structure is destroyed in response to a typical endogenous stimulus (GSH) to unload drugs. The dissociation of the drug-loaded nanogels accelerates the intracellular release of DOX and BTZ and further enhances the therapeutic efficacy. In vitro and in vivo investigations revealed that the dual-drug loaded polymeric nanogels exhibited a strong ability to suppress tumor growth. This study thus proposes a new perspective on the production of multifunctional polymeric nanogels through the introduction of different functional monomers.

Delivery nanoplatforms based on dynamic covalent chemistry

As a paramount factor to restrict the potential action of drugs and biologics, nanoplatforms based on dynamic covalent chemistry have been demonstrated as promising candidates to fulfill the full requirements during the whole delivery process by the virtue of their remarkable features such as adaptiveness, stimuli-responsiveness, specificity, reversibility and feasibility. This contribution summarizes the latest progress in dynamic covalent bond-based nanoplatforms with improved delivery efficiency and therapeutic performance. In addition, major challenges and perspectives in this field are also discussed. We expect that this feature article will provide a valuable and systematic reference for the further development of dynamic covalent bond-based nanoplatforms.

Nanoparticles prepared from pterostilbene reduce blood glucose and improve diabetes complications

BACKGROUND

Diabetes complications are the leading cause of mortality in diabetic patients. The common complications are decline in antioxidant capacity and the onset of micro-inflammation syndrome. At present, glucose-responsive nanoparticles are widely used, as they can release insulin-loaded ultrafine particles intelligently and effectively reduce blood sugar. However, the toxicology of this method has not been fully elucidated. The plant extracts of pterostilbene (PTE) have a wide range of biological applications, such as antioxidation and inflammatory response improvement. Therefore, we have proposed new ideas for the cross application of plant extracts and biomaterials, especially as part of a hypoglycaemic nano-drug delivery system.

RESULTS

Based on the PTE, we successfully synthesised poly(3-acrylamidophenyl boric acid-b-pterostilbene) (p[AAPBA-b-PTE]) nanoparticles (NPs). The NPs were round in shape and ranged between 150 and 250 nm in size. The NPs possessed good pH and glucose sensitivity. The entrapment efficiency (EE) of insulin-loaded NPs was approximately 56%, and the drug loading (LC) capacity was approximately 13%. The highest release of insulin was 70%, and the highest release of PTE was 85%. Meanwhile, the insulin could undergo self-regulation according to changes in the glucose concentration, thus achieving an effective, sustained release. Both in vivo and in vitro experiments showed that the NPs were safe and nontoxic. Under normal physiological conditions, NPs were completely degraded within 40 days. Fourteen days after mice were injected with p(AAPBA-b-PTE) NPs, there were no obvious abnormalities in the heart, liver, spleen, lung, or kidney. Moreover, NPs effectively reduced blood glucose, improved antioxidant capacity and reversed micro-inflammation in mice.

CONCLUSIONS

p(AAPBA-b-PTE) NPs were successfully prepared using PTE as raw material and effectively reduced blood glucose, improved antioxidant capacity and reduced the inflammatory response. This novel preparation can enable new combinations of plant extracts and biomaterials to adiministered through NPs or other dosage forms in order to regulate and treat diseases.

2,2-Bis(hydroxymethyl) propionic acid based cyclic carbonate monomers and their (co)polymers as advanced materials for biomedical applications

Designing grafted biodegradable polymers with tailored multi-functional properties is one of the most researched fields with extensive biomedical applications. Among many biodegradable polymers, polycarbonates have gained much attention due to their ease of synthesis, high drug loading, and excellent biocompatibility profiles. Among various monomers, 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) derived cyclic carbonate monomers have been extensively explored in terms of their synthesis as well as their polymerization. Since the late 90s, significant advancements have been made in the design of bis-MPA derived cyclic carbonate monomers as well as in their reaction schemes. Currently, bis-MPA derived polycarbonates have taken a form of an entire platform with a multitude of applications, the latest being in the field of nanotechnology, targeted drug, and nucleic acid delivery. The present review outlines an up to date developments that have taken place in the last two decades in the design, synthesis, and biomedical applications of bis-MPA derived cyclic carbonates and their (co)polymers.

Functionalized Particles Designed for Targeted Delivery

Pure bioactive compounds alone can only be exceptionally administered in medical treatment. Usually, drugs are produced as various forms of active compounds and auxiliary substances, combinations assuring the desired healing functions. One of the important drug forms is represented by a combination of active substances and particle-shaped polymer in the nano- or micrometer size range. The review describes recent progress in this field balanced with basic information. After a brief introduction, the paper presents a concise overview of polymers used as components of nano- and microparticle drug carriers. Thereafter, progress in direct synthesis of polymer particles with functional groups is discussed. A section is devoted to formation of particles by self-assembly of homo- and copolymer-bearing functional groups. Special attention is focused on modification of the primary functional groups introduced during particle preparation, including introduction of ligands promoting anchorage of particles onto the chosen living cell types by interactions with specific receptors present in cell membranes. Particular attention is focused on progress in methods suitable for preparation of particles loaded with bioactive substances. The review ends with a brief discussion of the still not answered questions and unsolved problems.

Imidazole-Mediated Dual Location Disassembly of Acid-Degradable Intracellular Drug Delivery Block Copolymer Nanoassemblies

Acid-degradable (or acid-cleavable) polymeric nanoassemblies have witnessed significant progress in anti-cancer drug delivery. However, conventional nanoassemblies designed with acid-cleavable linkages at a single location have several challenges, such as, sluggish degradation, undesired aggregation of degraded products, and difficulty in controlled and on-demand drug release. Herein, a strategy that enables the synthesis of acid-cleavable nanoassemblies labeled with acetaldehyde acetal groups in both hydrophobic cores and at core/corona interfaces, exhibiting synergistic response to acidic pH at dual locations and thus inducing rapid drug release is reported. The systematic analyses suggest that the acid-catalyzed degradation and disassembly are further enhanced by decreasing copolymer concentration (i.e., increasing proton/acetal mole ratio). Moreover, incorporation of acid-ionizable imidazole pendants in the hydrophobic cores improve the encapsulation of doxorubicin, the anticancer drug, through π-π interactions and enhance the acid-catalyzed hydrolysis of acetal linkages situated in the dual locations. Furthermore, the presence of the imidazole pendants induce the occurrence of core-crosslinking that compensates the kinetics of acetal hydrolysis and drug release. These results, combined with in vitro cell toxicity and cellular uptake, suggest the versatility of the dual location acid-degradation strategy in the design and development of effective intracellular drug delivery nanocarriers.

Self-Assembling pH-Responsive Nanoparticle Platform Based on Pectin-Doxorubicin Conjugates for Codelivery of Anticancer Drugs

Pharmaceutical science based on biological nanotechnology is developing rapidly in parallel with the development of nanomaterials and nanotechnology in general. Pectin is a natural polysaccharide obtainable from a wide range of sources. Here, we show that doxorubicin (DOX)-conjugated hydrophilic pectin (PET) comprising an amphiphilic polymer loaded with hydrophobic dihydroartemisinin (DHA) self-assemble into nanoparticles. Importantly, conjugated DOX and DHA could be released quickly in a weakly acidic environment by cleavage of the acid-sensitive acyl hydrazone bond. Confocal microscopy and flow cytometry confirmed that these PET-DOX/DHA nanoparticles efficiently delivered DOX into the nuclei of MCF-7 cells. Significant tumor growth reduction was monitored in a female C57BL/6 mouse model, showing that the PET-DOX/DHA nanoparticle-mediated drug delivery system inhibited tumor growth and may improve therapy. Thus, we have demonstrated that pectin may be useful in the design of materials for biomedical applications.

A cyanine-based polymeric nanoplatform with microenvironment-driven cascaded responsiveness for imaging-guided chemo-photothermal combination anticancer therapy

Finding out how to overcome multistage biological barriers for nanocarriers in cancer therapy to obtain highly precise drug delivery is still a challenge. Herein, we prepared a multistage and cascaded switchable polymeric nanovehicle, self-assembled from polyethylene glycol grafted amphiphilic copolymer containing hydrophobic poly(ortho ester) and hydrophilic ethylenediamine-modified poly(glycidyl methacrylate) (PEG-g-p(GEDA-co-DMDEA)) for imaging-guided chemo-photothermal combination anticancer therapy. Notably, a novel ATRP initiator containing cyanine dye was designed and attached to the polymer, providing the nanovehicle with NIR-light induced photothermal and fluorescent properties. The PEG shell displayed tumor-microenvironment-induced detachment, resulting in the surface charge change of the nanovehicle from neutral to positive and thus enhancing cellular uptake. Subsequently, the hydrophobic pDMDEA hydrolyzed into a hydrophilic segment in the acidic lysosome, leading to sufficient drug release. Finally, with the aid of the photothermal property, the therapeutic drug DOX successfully escaped from the lysosome to exert chemotherapy. This well-defined polymeric nanoplatform promoted the development of designing novel theranostic polymeric nanovehicles for precise cancer therapy.

Smart transformable nanomedicines for cancer therapy

Despite that great progression has been made in nanoparticulate drug delivery systems (nano-DDS), multiple drug delivery dilemmas still impair the delivery efficiency of nanomedicines. Rational design of smart transformable nano-DDS based on the in vivo drug delivery process represents a promising strategy for overcoming delivery obstacle of nano-DDS. In recent years, tremendous efforts have been devoted to developing smart transformable anticancer nanomedicines. Herein, we provide a review to outline the advances in this emerging field. First, smart size-reducible nanoparticles (NPs) for deep tumor penetration are summarized, including carrier degradation-induced, protonation-triggered and photobleaching-induced size reduction. Second, emerging transformable nanostructures for various therapeutic applications are discussed, including prolonging tumor retention, reversing drug-resistance, inhibiting tumor metastasis, preventing tumor recurrence and non-pharmaceutical therapy. Third, shell-detachable nanocarriers are introduced, focusing on chemical bonds breaking-initiated, charge repulsion-mediated and exogenous stimuli-triggered shell detachment approaches. Finally, the future perspectives and challenges of transformable nanomedicines in clinical cancer therapy are highlighted.

A novel self-targeting theranostic nanoplatform for photoacoustic imaging-monitored and enhanced chemo-sonodynamic therapy

Sonodynamic therapy has attracted wide attention as a noninvasive therapy due to deep tissue penetration. However, majority sonosensitizers often suffer from poor physiological stability, rapid blood clearance and nonspecific targeting, which seriously hinders their further practical applications. Inspired by the concept of active targeting drug delivery, both dual-functional chemo-drug pemetrexed (PEM, emerges an innate affinity toward the folate receptor) and amphiphilic d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) were selected to be covalently linked by an esterase-responsive ester linkage. The synthesized self-targeting TPGS-PEM prodrug and indocyanine green (ICG) as functional motifs can be self-assembled into a TPGS-PEM-ICG nanoplatform within an aqueous medium. The TPGS-PEM-ICG nanoplatform with outstanding structural and physiological stability not only protects the sonosensitizer from reticular endothelial system clearance but also achieves active targeting drug delivery and efficient tumor enrichment. Moreover, TPGS-PEM-ICG nanoplatform can selectively recognize tumor cells and then realize on-demand drug burst release by multiple stimuli of internal lysosomal acidity, esterase and external ultrasound, which guarantee low side effects toward normal tissues and organs. It is also worth noting that our nanoplatform exhibits protruding tumor enrichment under the precise guidance of photoacoustic/fluorescence imaging. Further in vitro and in vivo experimental results well confirmed that the TPGS-PEM-ICG nanoplatform possesses enhanced chemo-sonodynamic effects. Interestingly, the highly toxic reactive oxygen species can remarkably reduce the blood oxygen saturation signal of the tumor microenvironment via precise, multifunctional and high-resolution photoacoustic imaging. Taken together, the TPGS-PEM-ICG nanoplatform can be expected to hold enormous potential for diagnosis, prognosis and targeted therapy for tumor.

A Drug-Free Therapeutic System for Cancer Therapy by Diselenide-Based Polymers Themselves

The application of nanotechnology-based drug delivery systems has resulted in great progresses in cancer therapy. However, current systems ultimately depend on the action of the drug itself and almost all nanocarriers only serve as excipients without any therapeutic efficacy. Herein, a drug-free therapeutic system is put forward, in which synthetic polymers themselves naturally exhibit effective anticancer activity without the loading of additional chemotherapy drugs. Aiming at this goal, amphiphilic poly(diselenide-carbonate) copolymers (PSeSeTMC), consisting of monomethyl ether poly(ethylene glycol) and diselenide-based polycarbonates, are designed and synthesized to build spherical nanoparticles, which show effective and broad-spectrum anticancer activities against multiple cancer cell lines and high selectivity toward cancer cells. Moreover, the anticancer activities can be well controlled by tuning the selenium contents in polymers. Mechanistic investigations indicate that PSeSeTMC can selectively induce cancer cells to express excessive reactive oxygen species, thereby leading to significant cellular apoptosis. In vivo antitumor studies further demonstrate high therapeutic efficacy and low side effects on normal tissue. Overall, this work provides a novel approach for cancer therapy by utilizing carriers themselves. Considering the fabrication process is pretty simple, this diselenide-based polymeric system has great potential in clinical translation.

Polymeric Nanoparticles and Their Novel Modifications for Targeted Delivery of Bortezomib

Bortezomib (BTZ) as a specific proteasome inhibitor is used to inhibit proliferation and migration of tumor cell in variety of cancers. Targeted delivery of this drug not only would minimize its unwanted side effects but also might improve its efficacy. This purpose could be gotten through different pathways but using efficient carriers may be the best one without using any additional ingredients/ materials. Some polymer based nanoparticles with specific functional groups have the ability to interact with boronic acid moiety in BTZ. This reaction might play an important role not only in cancer targeting therapy but also in loading and release properties of this drug. Novel modification such as making multifunctional or pH-sensitive nanocarriers, may also improve anticancer effect of BTZ. This review might have remarkable effect on researchers’ consideration about other possible interactions between BTZ and polymeric nanocarriers that might have great effect on its remedy pathway. It has the ability to brought bright ideas to their minds for novel amendments about other drugs and delivery systems.

Stimuli-Responsive Aliphatic Polycarbonate Nanocarriers for Tumor-Targeted Drug Delivery

Nanoparticles based on amphiphilic copolymers with tunable physicochemical properties can be used to encapsulate delicate pharmaceutics while at the same time improving their solubility, stability, pharmacokinetic properties, reducing immune surveillance, or achieving tumor-targeting ability. Those nanocarriers based on biodegradable aliphatic polycarbonates are a particularly promising platform for drug delivery due to flexibility in the design and synthesis of appropriate monomers and copolymers. Current studies in this field focus on the design and the synthesis of new effective carriers of hydrophobic drugs and their release in a controlled manner by exogenous or endogenous factors in tumor-specific regions. Reactive groups present in aliphatic carbonate copolymers, undergo a reaction under the action of a stimulus: e.g., acidic hydrolysis, oxidation, reduction, etc. leading to changes in the morphology of nanoparticles. This allows the release of the drug in a highly controlled manner and induces a desired therapeutic outcome without damaging healthy tissues. The presented review summarizes the current advances in chemistry and methods for designing stimuli-responsive nanocarriers based on aliphatic polycarbonates for controlled drug delivery.

Bicomponent polymeric micelles for pH-controlled delivery of doxorubicin

Stimuli-responsive drug delivery systems (DDSs) are expected to realize site-specific drug release and kill cancer cells selectively. In this study, a pH-responsive micelle was designed utilizing the pH-sensitivity of borate bonds formed between dopamine and boronic acid. First, methyl (polyethylene glycol)-block-polycaprolactone (mPEG-PCL) was conjugated with 4-cyano-4-(thiobenzoylthio)pentanoic acid (CTP) to obtain a macroinitiator. Two different segments poly(dopamine methacrylamide) (PDMA) and poly(vinylphenylboronic acid) (PVBA) were then grafted to the end of mPEG-PCL. Two triblock copolymers, mPEG-PCL-PDMA and mPEG-PCL-PVBA, were then obtained by reversible addition-fragmentation transfer (RAFT) polymerization. These copolymers and their mixture self-assembled in aqueous solution to form micelles that were able to load hydrophobic anticancer drug doxorubicin (DOX). These two-component micelles were found to be pH-sensitive, in contrast to the one-component micelles. Furthermore, MTT studies showed that the micelles were almost nontoxic. The DOX-loaded micelles showed cytotoxicity equivalent to that of DOX at high concentration. In vivo antitumor experiments showed that this pH-sensitive polymeric micellar system had an enhanced therapeutic effect on tumors. These two-component boronate-based pH micelles are universally applicable to the delivery of anticancer drugs, showing great potential for cancer therapy.

Tumor-targeting and imaging micelles for pH-triggered anticancer drug release and combined photodynamic therapy

Herein, we construct a charge - switchable polymer nano micelles poly (2-(hexamethyl eneimino) ethyl methacrylate) - b - poly (ethylene glycol) monomethyl ether methacrylate) - b - poly (diethyl enetriaminepentaacetic acid methacrylate) - b - poly (1-vinyl imidazole) - b - poly (4-vinyl phenylboronic acid) (PC7A-PEG-DTPA-VI-PBA) in different pH solutions. DOX released faster from micelles in a weakly acidic environment (pH 5.0) than at pH 7.4. In order to enhance the anti-tumor effect, the imidazole functional groups in the polymer were used to coordinate CdSeTe quantum dots (QDs) for photodynamic treatment (PDT). In addition, the surfaces of the micelles were further decorated with phenylboronic acidas a targeting group, using DTPA chelating ^99mTc for SPECT imaging.It has been successfully demonstrated that the nanoparticles have a good cumulative effect on the tumor site.The structure of the polymer was characterized by ¹HNMR. The morphology and particle size of the micelles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The drug loading capacity (DLC) and drug loading efficiency (DLE) of the micelles were analyzed by ultraviolet visible spectroscopy. And the pH-sensitive drug release and cytotoxicity of the micelles were verified in vitro. In vitro experiments showed that the nano micelles were noncytotoxic to different cell lines, while DOX@CdSeTe@PC7A-PEG-DTPA-VI-PBA inhibited the proliferation and promoted the apoptosis of B16F10 cells. An in vivo study with C57BL tumor-bearing mice indicated that DOX@CdSeTe@PC7A-PEG-DTPA-VI-PBA nano micelles efficiently inhibited tumor growth. Results showed that the nano micelles had good pH responsibility and biocompatibility, and the loaded DOX could be released in the weak acidic environment of tumor cells, and it was expected to be a good drug delivery system.

Synthesis of Functionalized Cyclic Carbonates through Commodity Polymer Upcycling

Functionalized cyclic carbonates are attractive monomers for the synthesis of innovative polycarbonates or polyurethanes for various applications. Even though their synthesis has been intensively investigated, doing so in a sustainable and efficient manner remains a challenge. Herein, we propose an organocatalytic procedure based on the depolymerization of a commodity polymer, bisphenol A based polycarbonate (BPA-PC). Different carbonate-containing heterocycles are obtained in good to excellent yields employing BPA-PC as a sustainable and inexpensive source of carbonate, including functionalized six-membered cyclic carbonates.

Intelligent Cellulose Nanofibers with Excellent Biocompatibility Enable Sustained Antibacterial and Drug Release via a pH-Responsive Mechanism

Novel nanosized biomass-based pH-responsive cellulose nanofibers (CNF-PEI) with excellent biocompatibility were tailored by grafting polyethylenimine (PEI) onto carboxylated cellulose nanofibers (CNF-COOH); the active site (-COOH, 0.96 mmol/g) was anchored on cellulose nanofibers (CNFs) to introduce PEI with a high density (10.57 mmol/g) of amino groups. The as-prepared CNF-PEI not only maintained the good properties of CNFs but also possessed excellent biocompatibility and pH-responsive properties, offering interesting possibilities for pH-induced sustained drug release and medical dressing. The CNF-PEI showed rapid wettability conversion from hydrophilic, underwater superoleophobic (WCA = 20.7°, OCA = 159.3°) to hydrophobic, superoleophilic (WCA = 129.6°, OCA = 29.7°) in response to pH change from acidic conditions to alkaline conditions. The antibacterial activity of CNF-PEI toward Escherichia coli and Listeria monocytogenes was 100% and 94.6% under acidic conditions, respectively. Furthermore, the pH-responsive mechanism of CNF-PEI was revealed by XPS, ¹³C NMR, ¹H NMR, and AFM analyses.