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Triple-negative breast cancer (TNBC) causes great suffering to patients because of its heterogeneity, poor prognosis, and chemotherapy resistance. Ferroptosis is characterized by iron-dependent oxidative damage by accumulating intracellular lipid peroxides to lethal levels, and plays a vital role in the treatment of TNBC based on its intrinsic characteristics. To identify the relationship between chemotherapy resistance and ferroptosis in TNBC, we analyzed the single cell RNA-sequencing public dataset of GSE205551. It was found that the expression of Gpx4 in DOX-resistant TNBC cells was significantly higher than that in DOX-sensitive TNBC cells. Based on this finding, we hypothesize that inducing ferroptosis by inhibiting the expression of Gpx4 can reduce the resistance of TNBC to DOX and enhance the therapeutic effect of chemotherapy on TNBC. Herein, dihydroartemisinin (DHA)-loaded polyglutamic acid-stabilized Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 -PGA-DHA) was combined with DOX-loaded polyaspartic acid-stabilized Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 -PASP-DOX) for ferroptosis-enhanced chemotherapy of TNBC. Compared with Fe 3 O 4 -PASP-DOX, Fe 3 O 4 -PGA-DHA + Fe 3 O 4 -PASP-DOX demonstrated significantly stronger cytotoxicity against different TNBC cell lines and achieved significantly more intracellular accumulation of reactive oxygen species and lipid peroxides. Furthermore, transcriptomic analyses demonstrated that Fe 3 O 4 -PASP-DOX-induced apoptosis could be enhanced by Fe 3 O 4 -PGA-DHA-induced ferroptosis and Fe 3 O 4 -PGA-DHA + Fe 3 O 4 -PASP-DOX might trigger ferroptosis in MDA-MB-231 cells by inhibiting the PI3K/AKT/mTOR/GPX4 pathway. Fe 3 O 4 -PGA-DHA + Fe 3 O 4 -PASP-DOX showed superior anti-tumor efficacy on MDA-MB-231 tumor-bearing mice, providing great potential for improving the therapeutic effect of TNBC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ferroptosis, as a form of cell death different from apoptosis, is very promising for the treatment of cancer in nonapoptotic systems. Since iron is a key component in the induction of ferroptosis in cells, the use of iron-based nanomaterials in treating cancer through ferroptosis is of great significance. Therefore, in this study, magnetic nanoparticles (MNP) were coated with the zwitterionic polymer poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and then loaded with sorafenib (SRF) to obtain drug-loaded composite nanoparticles MNP@PMPC-SRF. Fe 3 O 4 provided a large number of ferric/ferrous ions as an iron source, releasing Fe 2+ for the regulation of the ferroptosis process and enhancing the effect of the induced cellular ferroptosis on the treatment of colon cancer with SRF. The zwitterionic polymer PMPC effectively extended the blood circulation time, resulting in an enhanced tumor accumulation of the nanodrug. MNP@PMPC-SRF exhibited good biocompatibility for in vivo application and showed an excellent tumor inhibitory effect on HCT116 tumor-bearing nude mice.

In recent years, zeolitic imidazolate framework-8 (ZIF-8) has become an attractive metal organic framework (MOF) material in drug delivery for cancer chemotherapy. However, as a drug delivery system, ZIF-8 still shows some disadvantages, such as short blood circulation time and poor tumor targeting, leading to reduced drug delivery efficiency and unsatisfactory treatment. Herein, we developed a phosphorylcholine-based zwitterionic copolymer coated ZIF-8 nanodrug (DOX@ZIF-8@P(MPC-co-C7A)), and the obtained nanodrug was prepared via a charge-conversional zwitterionic copolymer coating on DOX@ZIF-8 composites. In this system, DOX was encapsulated in the framework of ZIF-8, which could reduce the drug leakage in the bloodstream. The phosphorylcholine-based zwitterionic copolymer effectively extended the blood circulation time, resulting in enhanced tumor accumulation of the nanodrug. Once the nanodrug reached the tumor site, the surface charge of the system could rapidly convert to positive, resulting in an enhanced tumor cellular uptake. Finally, in the acidic environment inside intracellular organelles, DOX will be released rapidly for chemotherapy owing to the fast disintegration of ZIF-8 frameworks. Therefore, the obtained nanodrug could effectively inhibit the growth of A549-bearing tumors (93.2% tumor inhibition rate) with negligible side effects. Overall, this work significantly improved the drug delivery efficiency of ZIF-8, which may pave the way for the biomedical applications of ZIF-8 crystals in anti-tumor drug delivery.

Although cancer immunotherapy has emerged as a tremendously promising cancer therapy method, it remains effective only for several cancers. Photoimmunotherapy (e.g., photodynamic/photothermal therapy) could synergistically enhance the immune response of immunotherapy. However, excessively generated immunogenicity will cause serious inflammatory response syndrome. Herein, biomimetic magnetic nanoparticles, Fe 3 O 4 -SAS @ PLT, are reported as a novel approach to sensitize effective ferroptosis and generate mild immunogenicity, enhancing the response rate of non-inflamed tumors for cancer immunotherapy. Fe 3 O 4 -SAS@PLT are built from sulfasalazine (SAS)-loaded mesoporous magnetic nanoparticles (Fe 3 O 4 ) and platelet (PLT) membrane camouflage and triggered a ferroptotic cell death via inhibiting the glutamate-cystine antiporter system X c - pathway. Fe 3 O 4 -SAS @ PLT-mediated ferroptosis significantly improves the efficacy of programmed cell death 1 immune checkpoint blockade therapy and achieves a continuous tumor elimination in a mouse model of 4T1 metastatic tumors. Proteomics studies reveal that Fe 3 O 4 -SAS @ PLT-mediated ferroptosis could not only induce tumor-specific immune response but also efficiently repolarize macrophages from immunosuppressive M2 phenotype to antitumor M1 phenotype. Therefore, the concomitant of Fe 3 O 4 -SAS @ PLT-mediated ferroptosis with immunotherapy are expected to provide great potential in the clinical treatment of tumor metastasis., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

One of the major limitations of current cancer therapy is the inability to destroy tumors with high efficacy and minimal invasiveness. Herein, we developed a proof-of-concept fixed-point "blasting" strategy to destroy the "castle" of tumors and realized efficient interventional photothermal therapy. The "blasting" materials were composed of photothermal nanoparticles (ancient ink nanoparticles, AINP) and a low boiling point phase change agent (perfluoromethylcyclopentane, FMCP). An injectable in situ-forming thermal-responsive hydrogel composed of biodegradable and biocompatible polymers was employed as a carrier to load the AINP and FMCP. The obtained hydrogel system was a flowable aqueous solution at low or room temperature for facile injection; meanwhile, once administered, it rapidly transformed into a fixed gel at a body temperature of about 37 °C. This unique property could effectually fix the AINP and FMCP and thus restrict the destruction region inside the tumor. Subsequently, triggered by second window near-infrared light, the solid tumors were effectively destroyed by a mild photothermal effect and the subsequent gas mechanical damage. We envisage that this fixed-point "blasting" strategy will pave a new way for the next generation of cancer-interventional photothermal therapy.

Multiple drug resistance (MDR) exhibited by cancer cells and low intratumor accumulation of chemotherapeutics are the main obstacles in cancer chemotherapy. Herein, the preparation of a redox-responsive sulfur dioxide (SO 2 )-releasing nanosystem, with high SO 2 -loading capacity, aimed at improving the treatment efficacy of cancers exhibiting MDR is described. The multifunctional nanomedicine (MON-DN@PCBMA-DOX) is designed and constructed by coating mesoporous organosilica nanoparticles with a zwitterionic polymer, poly(carboxybetaine methacrylate) (PCBMA), which can concurrently load SO 2 prodrug molecules (DN, 2,4-dinitrobenzenesulfonylchloride) and chemotherapeutics (DOX, doxorubicin). The generated SO 2 molecules can sensitize cells to chemotherapy and overcome the MDR by downregulating the expression of P-glycoprotein. Furthermore, the PCBMA coating prolongs the blood circulation time of the inner core, leading to an increased intratumor accumulation of the nanomedicine. Owing to the prolonged blood circulation, enhanced tumor accumulation, and SO 2 sensitization of cells to chemotherapy, the nanomedicine exhibits excellent tumor suppression with a tumor inhibition rate of 94.8%, and might provide a new platform for cancer therapy., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Long blood circulation is the basic requirement of advanced drug delivery systems for tumor treatment, which leads to enhanced tumor therapeutic efficiency and reduced side effects. However, the pharmacokinetics of the current nanoparticles in vivo is still unsatisfactory, which leads to limited success to translate nanoparticles into clinical applications. Inspired by the natural cell membrane-coating strategy, a series of zwitterionic polymer membranes are firstly developed and coated onto different kinds of nanoparticles in this work. Intriguingly, the zwitterionic polymer membrane shows stronger protein adsorption resistance and reduced macrophage uptake compared with the corresponding zwitterionic polymer brush or the red blood cell (RBC) membrane, which results in longer blood circulation time and higher tumor accumulation of the coated nanoparticles. Combined with the photothermal effect of model nanoparticles, Fe 3 O 4 , zwitterionic polymer membrane-coated Fe 3 O 4 shows enhanced photothermal therapy (PTT) efficacy on A549 tumors compared with the corresponding zwitterionic polymer brush or RBC membrane-coated Fe 3 O 4 . Notably, Fe 3 O 4 coated by carboxybetaine-based biomimic membranes exhibits the ultra-long blood circulation (t 1/2  = 96.0 h) and strongest PTT efficacy compared with those coated by phosphorylcholine-based or sulfobetaine-based biomimic membranes. In addition, the zwitterionic biomimic membrane exhibits rapid glutathione-triggered degradation with the products of low molecular weight (<2000 g mol -1 ). Therefore, the biodegradable zwitterionic biomimic membrane coating offers a universal platform for the design and application of long-circulating biomedical nanoparticles, which may pave the way for the clinical applications of biomedical nanoparticles in tumor therapy., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Chemo-photothermal therapy has attracted intensive attention because of its low side effects and better therapeutic efficiency. Although many photothermal agents have been loaded with chemotherapeutic drugs for chemo-photothermal therapy, their applications are limited by complex synthetic protocols and long-term safety. Therefore, there is significant clinical value in the development of a simple system of biocompatible and biodegradable photothermal nanomaterials with high payloads of chemotherapeutic drugs for chemo-photothermal synergistic therapy., Materials and Methods: In this study, PEG-modified polydopamine nanoparticles with mesoporous structure (MPDA-PEG) were successfully obtained by an emulsion-induced interface assembly strategy. Subsequently, paclitaxel (PTX) dissolved in acetone was loaded into the mesoporous channels of MPDA-PEG nanoparticles by solution absorption method. A PTX-loaded MPDA-PEG (MPDA-PEG-PTX) nanoplatform for combination of photothermal therapy (PTT) and chemotherapy was developed., Results: The synthesized MPDA-PEG nanoparticles had a great photothermal effect under near-infrared (NIR) laser irradiation and exhibited an enhanced photothermal effect with the increase of particle size. Meanwhile, MPDA-PEG nanoparticles also had a high payload of PTX, and the PTX release could be greatly accelerated by elevated temperature from photothermal effect. In MTT cytotoxicity assay, A549 cells incubated with MPDA-PEG-PTX under NIR laser irradiation (PTT + chemotherapy group) exhibited better therapeutic effect than single chemotherapy (MPDA-PEG-PTX group) and PTT (MPDA-PEG + Laser group). The synergistic therapeutic effect of MPDA-PEG-PTX with NIR laser irradiation in vivo was further investigated under the guidance of photoacoustic imaging (PAI), tumors of nude mice treated with MPDA-PEG-PTX with NIR laser irradiation were completely eliminated with minimal side effect., Conclusion: The MPDA-PEG-PTX nanoplatform is a simple and effective platform which can completely inhibit tumor growth with minimal side effects under NIR irradiation, and it exhibits better therapeutic effect than single chemotherapy and PTT., Competing Interests: The authors report no conflicts of interest in this work., (© 2019 Zhang et al.)

From the conception of atom economy to develop multifunctional nanomaterials, it is important to construct nanomaterials by maximizing functional units while minimizing unnecessary components. Noteworthy, metal-organic framework (MOF) nanoparticles are excellent examples to meet this idea. Current approaches for multifunctional MOFs are mainly based on encapsulation of functional molecules or multistep modification; however, high risk for leakage and burst release and time-consuming and complicated organic synthesis limit their applications. Here, we report a one-pot approach to build the defect structure of a metal organic framework with near-infrared dye (cypate), which is based on the interaction between Fe 3+ and carboxyl group of cypate molecules, to construct a multifunctional MOF. Moreover, this system can achieve multimodal imaging guided phototherapy. Subsequently, the precise cancer phototherapy is investigated in vivo, and the tumors are entirely eliminated without obvious side effects, demonstrating the high efficacy and safety of this multifunctional platform. Hence, it is expected that not only this system is simple, safe, and highly effective but also our method of creating defect structures of MOFs will open a new way to develop multifunctional nanoplatforms for bioapplications.

Zwitterionic polymer nanocarriers have attracted much attention in recent years due to their desirable biocompatibility and anti-fouling properties. However, the super-hydrophilic and neutral charge of zwitterionic polymer results in weak interactions with negatively charged cell membranes, which leads to suboptimal uptake by tumor cells. Herein, a series of biodegradable poly(2-methacryloyloxyethyl phosphorylcholine-s-s-vinylimidazole) (PMV) nanogels with uniform spherical shape was fabricated by one-step reflux precipitation polymerization, which was clean and efficient. The PMV nanogels remained in zwitterionic state at physiological pH (pH 7.4) and were converted rapidly to positive charged state at tumor extracellular pH (pH 6.5). Proton nuclear magnetic resonance spectra and acid-base titration experiment proved that the charge-conversion ability of PMV nanogels was attributed to protonation of the imidazole ring in an acidic environment. Protein stability experiment showed that PMV nanogels exhibited a protein-adsorption resistance at pH 7.4 for as long as 7 days while adsorbed protein rapidly at pH 6.5. Moreover, PMV nanogels showed a reducing-labile property, which was able to degrade into short linear polymer chains in the presence of reduction agents. Therefore, the doxorubicin (DOX) release profile was controlled finely with a low DOX leakage under physiological conditions (7.8% in 48 h) and a rapid DOX release in 10 mM glutathione at pH 7.4 (78.9% in 48 h). Confocal laser scanning microscope and flow cytometry showed that the PMV nanogels exhibit an enhanced cellular uptake by tumor cells at pH 6.5 compared with pH 7.4, which allows for a severe cytotoxic effect of DOX-loaded PMV nanogels against tumor cells., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Carbon monoxide (CO) gas therapy combined with chemotherapy and photothermal therapy (PTT) is a promising treatment mode for malignant tumor. Herein, we firstly reported doxorubicin (DOX) loaded Mn carbonyl modified Fe (Ⅲ)-based nanoMOFs (MIL-100) coated PEGylated magnetic carbon nanoparticles (denoted as MCM@PEG-CO-DOX NPs) as theranostics nanoplatforms for near-infrared (NIR)-responded CO-DOX combination therapy. MIL-100 as a good nanocarrier of DOX with high loading capacity can also chelate the Mn carbonyl after a smart modification. Meanwhile, magnetic carbon core possessed photothermal effect, which can convert the NIR light to heat by an 808 nm laser irradiation, resulting in the on-demand release of CO and DOX. As a result, combining with PTT, MCM@PEG-CO-DOX NPs killed tumor efficiently. Moreover, our synthesized MCM@PEG-CO-DOX NPs were capable of realizing tumor dual-mode imaging including magnetic resonance imaging (MRI) and photoacoustic imaging (PAI)., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Cell membrane coating has emerged as an intriguing biomimetic strategy to endow nanomaterials with functions and properties inherent to source cells for various biomedical applications. Hybrid membrane of different types of cells could be coated onto nanoparticle surface to achieve additional functions. Herein, we fused red blood cell (RBC) membrane together with MCF-7 cell membrane and fabricated an erythrocyte-cancer (RBC-M) hybrid membrane-camouflaged melanin nanoparticle (Melanin@RBC-M) platform for enhancing therapeutic efficacy of photothermal therapy (PTT). The fused RBC-M hybrid membrane vesicles retained both RBC and MCF-7 cell membrane proteins and the resultant Melanin@RBC-M exhibited prolonged blood circulation and homotypic targeting to source MCF-7 cells simultaneously. Interestingly, increasing MCF-7 membrane components in RBC-M significantly enhanced the homotypic targeting function of Melanin@RBC-M while increasing RBC membrane components in RBC-M effectively reduced the cellular uptake of Melanin@RBC-M by macrophages and improved their circulation time in the blood. After intravenous injection into MCF-7 tumor-bearing athymic nude mice, Melanin@RBC-M with 1:1 membrane protein weight ratio of RBC to MCF-7 exhibited significantly higher tumor accumulation and better PTT efficacy compared with other Melanin@RBC-M with different membrane protein weight ratios as well as pristine melanin nanoparticles, due to the optimal balance between prolonged blood circulation and homotypic targeting. In addition, in vitro photoacoustic results revealed that Melanin@RBC-M had a photoacoustic signal enhancement with the increase of nanoparticle size (64 → 148 nm) and the photoacoustic amplitudes increased linearly with nanoparticle concentration at the excitation wavelength ranged from 680 nm to 800 nm, which could be used for quantification of Melanin@RBC-M in vivo. Looking forward, coating hybrid membrane onto nanoparticles could add flexibility and controllability in enhancing nanoparticles functionality and offer new opportunities for biomedical applications., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has become a promising cancer treatment in recent years. However, their applications are limited by complex synthetic protocols and low efficacy. Hence, optimizing experimental approach and improving the efficiency of phototherapy is the current research focus. In this work, various pyrolysis temperatures and sizes of zeolitic imidazolate framework-8 (ZIF-8) derived carbon nanoparticles (ZCNs) are obtained by a simple direct pyrolysis of the ZIF-8 nanoparticles. Meanwhile, the ZCNs can be used as photothermal agents and photosensitizers to produce heat and reactive oxygen species simultaneously upon near-infrared laser irradiation. Moreover, it is observed that the phototherapy effects and photoacoustic (PA) signal of ZCNs could be enhanced with the increase in the nanoparticle size. Subsequently, guided by PA imaging, the therapeutic effect of ZCNs is investigated on a small animal model, where tumors are entirely eliminated with minimal side effect, demonstrating the high efficacy of the larger size of ZCNs through combination of PTT and PDT. Therefore, it is expected that the ZCN is a simple and highly effective phototherapeutic platform for oncotherapy, and the concept of size-dependent enhanced behavior of phototherapy and PA imaging will be very useful in the development of nanomaterials for cancer therapy.

Autophagy is a conservative eukaryotic pathway which plays a crucial role in maintaining cellular homeostasis, and dysfunction of autophagy is usually associated with pathological conditions. Recently, emerging reports have stressed that various types of nanomaterials and therapeutic approaches interfere with cellular autophagy process, which has brought up concerns to their future biomedical applications. Here, we present a study elaborating the relationships between autophagy and iron oxide nanoparticle (IONP)-mediated photothermal therapy in cancer treatment. Our results reveal that IONP photothermal effect could lead to autophagy induction in cancerous MCF-7 cells in a laser dose-dependent manner, and the inhibition of autophagy would enhance the photothermal cell killing by increasing cell apoptosis. In an MCF-7 xenograft model, cotreatment of autophagy inhibitor and IONP under laser exposure could promote the tumor inhibition rate from 43.26 to 68.56%, and the tumor immunohistochemistry assay of microtubule-associated protein 1-light chain 3 (LC3) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling also demonstrate augmentation in both autophagosomes accumulation and apoptosis in vivo. This work helps us to better understand the regulation of autophagy during IONP-mediated photothermal therapy and provides us with a potential combination therapeutic approach of autophagy modulators and photothermal agents.

Zwitterionic nanocarriers have emerged as a new class of biocompatible nanomaterials with outstanding stealth capability in blood circulation. In this work, a novel biodegradable zwitterionic nanogel based on poly(sulfobetaine methacrylate) (PSBMA) was developed for reduction-responsive drug delivery to tumors. PSBMA nanogels were facilely fabricated by one-step reflux precipitation polymerization with the advantage of being surfactant-free and time-saving. The disulfide bond not only endowed the nanogels degradability in a reduction environment but also be modified with a fluorescent group after partial reduction. In vitro release experiments disclosed that doxorubicin (DOX)-loaded PSBMA nanogels could hold the drugs firmly in physiological conditions (only 7% release in 24 h) and release the drugs rapidly and sufficiently in 10 mM glutathione (85% in 8 h). More interestingly, PSBMA nanogels displayed long circulation in blood after intravenous injection, and small change was found in half-life of nanogels between the first (34.1 h) and the second injection (30.5 h), indicating that there was no accelerated blood clearance phenomenon for these nanogels. Meanwhile, no obvious immunogenic response was detected after PSBMA nanogels were injected into BALB/c mice. Furthermore, PSBMA nanogels showed a high accumulation of 9.5 and 10.7% of injected dose per gram of tissue in tumors at 24 and 48 h post intravenous injection, respectively. With outstanding long circulation time, high tumor accumulation, and sufficient drug release in a reduction environment, DOX-loaded PSBMA nanogels demonstrated the strongest tumor growth inhibition effect among all of the treatment groups in human hypopharyngeal carcinoma-bearing mouse models. Therefore, our study provided a facile drug delivery platform based on biodegradable zwitterionic nanogels and may have great potential in tumor drug delivery.

In this study, we reported a strategy to improve delivery efficiency of a long-circulation biomimetic photothermal nanoagent for enhanced photothermal therapy through selectively dilating tumor vasculature. By using a simply nanocoating technology, a biomimetic layer of natural red blood cell (RBC) membranes was camouflaged on the surface of photothermal polypyrrole nanoparticles (PPy@RBC NPs). The erythrocyte-mimicking PPy NPs inherited the immune evasion ability from natural RBC resulting in superior prolonged blood retention time. Additionally, excellent photothermal and photoacoustic imaging functionalities were all retained attributing to PPy NPs cores. To further improve the photothermal outcome, the endothelin A (ET A ) receptor antagonist BQ123 was jointly employed to regulate tumor microenvironment. The BQ123 could induce tumor vascular relaxation and increase blood flow perfusion through modulating an ET-1/ET A transduction pathway and blocking the ET A receptor, whereas the vessel perfusion of normal tissues was not altered. Through our well-designed tactic, the concentration of biomimetic PPy NPs in tumor site was significantly improved when administered systematically. The study documented that the antitumor efficiency of biomimetic PPy NPs combined with specific antagonist BQ123 was particularly prominent and was superior to biomimetic PPy NPs (P < 0.05) and PEGylated PPy NPs with BQ123 (P < 0.01), showing that the greatly enhanced photothermal treatment could be achieved with low-dose administration of photothermal agents. Our findings would provide a promising procedure for other similar enhanced photothermal treatment by blocking ET A receptor to dramatically increase the delivery of biomimetic photothermal nanomaterials., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Photothermal therapy (PTT) has represented a promising noninvasive approach for cancer treatment in recent years. However, there still remain challenges in developing non-toxic and biodegradable biomaterials with high photothermal efficiency in vivo. Herein, we explored natural melanin nanoparticles extracted from living cuttlefish as effective photothermal agents and developed red blood cell (RBC) membrane-camouflaged melanin (Melanin@RBC) nanoparticles as a platform for in vivo antitumor PTT. The as-obtained natural melanin nanoparticles demonstrated strong absorption at NIR region, higher photothermal conversion efficiency (∼40%) than synthesized melanin-like polydopamine nanoparticles (∼29%), as well as favorable biocompatibility and biodegradability. It was shown that RBC membrane coating on melanin nanoparticles retained their excellent photothermal property, enhanced their blood retention and effectively improved their accumulation at tumor sites. With the guidance of their inherited photoacoustic imaging capability, optimal accumulation of Melanin@RBC at tumors was achieved around 4 h post intravenous injection. Upon irradiation by an 808-nm laser, the developed Melanin@RBC nanoparticles exhibited significantly higher PTT efficacy than that of bare melanin nanoparticles in A549 tumor-bearing mice. Given that both melanin nanoparticles and RBC membrane are native biomaterials, the developed Melanin@RBC platform could have great potential in clinics for anticancer PTT., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Smart polysaccharide-based anticancer phototherapeutic nanoparticles are prepared via a coordination-induced assembly process. Upon irradiated with a near infrared laser, the nanoparticles are not only able to simultaneously generate reactive oxygen species and hyperthermia that ablate tumors, but also possess tumor microenvironment-responsive off/on near infrared fluorescence and enhancement in photothermal effect, making them promising theranostic platform of cancer., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photothermal therapy (PTT) and photodynamic therapy (PDT) are promising cancer treatment modalities in current days while the high laser power density demand and low tumor accumulation are key obstacles that have greatly restricted their development. Here, magnetic composite nanoparticles for dual-modal PTT and PDT which have realized enhanced cancer therapeutic effect by mitochondria-targeting are reported. Integrating PTT agent and photosensitizer together, the composite nanoparticles are able to generate heat and reactive oxygen species (ROS) simultaneously upon near infrared (NIR) laser irradiation. After surface modification of targeting ligands, the composite nanoparticles can be selectively delivered to the mitochondria, which amplify the cancer cell apoptosis induced by hyperthermia and the cytotoxic ROS. In this way, better photo therapeutic effects and much higher cytotoxicity are achieved by utilizing the composite nanoparticles than that treated with the same nanoparticles missing mitochondrial targeting unit at a low laser power density. Guided by NIR fluorescence imaging and magnetic resonance imaging, then these results are confirmed in a humanized orthotropic lung cancer model. The composite nanoparticles demonstrate high tumor accumulation and excellent tumor regression with minimal side effect upon NIR laser exposure. Therefore, the mitochondria-targeting composite nanoparticles are expected to be an effective phototherapeutic platform in oncotherapy., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Hydrogen sulfide (H2S) functions as a protective gas transmitter in various physiological and pathological processes, but the lack of ideal donors severely hampers the clinical application of H2S. This study aims to construct a controlled release H2S donor and evaluate its protective effect on graft endothelium. Mesoporous silica nanoparticles (MSNs) were synthesized using the sol-gel method and loaded with diallyl trisulfide (DATS), an H2S-releasing agent named DATS-MSN. In vitro experiments showed that DATS-MSN could alleviate endothelial cell inflammation and enhance endothelial cell proliferation and migration. In vivo experiments demonstrated that the apoptosis of graft endothelium was mitigated in the presence of DATS-MSN. Our results indicated that DATS-MSN, releasing H2S in a controlled release fashion, could serve as an ideal H2S donor.

Polypyrrole composite nanoparticles with controlled shape are synthesized, which exhibit a morphology-dependent photothermal effect: the raspberry-like composite nanoparticles have a much better photothermal effect than the spherical ones, and the immune responses to the nanocomposites are also dependent on their morphology. The outstanding performance of the nanocomposites promises their potential application in photothermal therapy and immunotherapy of cancer., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbon-dot-based nanosensors are prepared through sequentially assembling a polymer/carbon dot multilayer shell on mesoporous silica nanoparticles with different crosslinking densities of disulfide bonds; they can be utilized to evaluate the gluthathione (GSH) concentration. In vitro cell assays demonstrate the feasibility of using such nanosensors in evaluating the intracellular redox state of different cells., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The development of theranostic systems capable of diagnosis, therapy, and target specificity is considerably significant for accomplishing personalized medicine. Here, a multifunctional rattle-type nanoparticle (MRTN) as an effective biological bimodal imaging and tumor-targeting delivery system is fabricated, and an enhanced loading ability of hydrophobic anticancer drug (paclitaxel) is also realized. The rattle structure with hydrophobic Fe3 O4 as the inner core and mesoporous silica as the shell is obtained by one-step templates removal process, and the size of interstitial hollow space can be easily adjusted. The Fe3 O4 core with hydrophobic poly(tert-butyl acrylate) (PTBA) chains on the surface is not only used as a magnetic resonance imaging (MRI) agent, but contributes to improving hydrophobic drug loading amount. Transferrin (Tf) and a near-infrared fluorescent dye (Cy 7) are successfully modified on the surface of the nanorattle to increase the ability of near-infrared fluorescence (NIRF) imaging and tumor-targeting specificity. In vivo studies show the selective accumulation of MRTN in tumor tissues by Tf-receptor-mediated endocytosis. More importantly, paclitaxel-loaded MRTN shows sustained release character and higher cytotoxicity than the free paclitaxel. This theranostic nanoparticle as an effective MRI/NIRF bimodal imaging probe and drug delivery system shows great potential in cancer diagnosis and therapy., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A strategy to prepare doxorubicin-loaded magnetic silk fibroin nanoparticles is presented. The nanoparticles serve as a nanometer-scale drug-delivery system in the chemotherapy of multidrug-resistant cancer under the guidance of a magnetic field. The magnetic tumor-targeting ability broadens the range of biomedical applications of silk fibroin, and the nanoparticle-assisted preparation strategy is useful for the advancement of other biomacromolecule-based materials., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nonporous silica transitional approach was employed to create core-shell architectural nanocomposites, which performed particularly well in morphology and controllable synthesis. The silica nanocomposites containing fluorescent solid SiO2 core and mesoporous silica shell (F-nSiO2/mSiO2) presented distinct structures of narrow size distribution, stable and shell thickness independent fluorescence, and high specific surface area. Furthermore, the thickness of mesoporous shell could be precisely tailored by the amount of TEOS and solid SiO2 seeds. Drug delivery study of F-nSiO2/mSiO2 with different mesoporous thicknesses were carried out, and Peppas equation was adopted to demonstrate the controlled releasing mechanism of doxorubicin (DOX). The diffusion rate of DOX from F-nSiO2/mSiO2 nanocomposites depended on the thickness of mesoporous shell and electrostatic interaction between drug and silanol group, which facilitated an enhanced drug releasing activity at pH 5.5 than 7.4. What's more, particles loaded DOX showed similar cytotoxicity compared with pure DOX, while no obvious cytotoxicity of carrier was observed in MTT tests for blank particles. These characteristics mentioned above implied that core/shell structured F-nSiO2/mSiO2 had a great potential for controlled drug delivery system., (Copyright © 2013 Elsevier Inc. All rights reserved.)

A controlled drug-delivery system has been developed based on mesoporous silica nanoparticles that deliver anticancer drugs into cancer cells with minimized side effects. The copolymer of two oligo(ethylene glycol) macromonomers cross-linked by the disulfide linker N,N'-bis(acryloyl)cystamine is used to cap hollow mesoporous silica nanoparticles (HMSNs) to form a core/shell structure. The HMSN core is applied as a drug storage unit for its high drug loading capability, whereas the polymer shell is employed as a switch owing to its redox/temperature dual responses. The release behavior in vitro of doxorubicin demonstrated that the loaded drugs could be released rapidly at higher temperature or in the presence of glutathione (GSH). Thus, the dual-stimulus polymer shell exhibiting a volume phase transition temperature higher than 37 °C can effectively avoid drug leakage in the bloodstream owing to the swollen state of the shell. Once internalized into cells, the carriers shed the polymer shell because of cleavage of the disulfide bonds by GSH, which results in the release of the loaded drugs in cytosol. This work may prove to be a significant development in on-demand drug release systems for cancer therapy., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The objective of this study was to develop and evaluate the antitumor activity and the safety of a delivery system containing mesoporous silica nanoparticles (MSN) coated with pH-responsive poly (N-isopropylacrylamide-co-methacrylic acid; P NIPAM-co-MAA) for doxorubicin (DOX) delivery (P-MSN-DOX) in vitro and in vivo. We reported that P-MSN-DOX nanoparticles (190 ± 30 nm) offered a DOX-loading coefficient of more than 20%. DOX release from the P-MSN-DOX formulation was pH-dependent with enhanced antitumor effects in vitro compared with traditional MSN-DOX, which was weakly cytotoxic due to negligible drug release at tested pHs. P-MSN-DOX circulated longer, with less cardiac and renal accumulation as shown by pharmacokinetics and biodistribution studies in vivo. Also, the P-MSN-DOX delivery system had greater antitumor activity in mice bearing a murine sarcoma S-180 cell line. This finding was correlated with both in vitro and in vivo. Subacute toxicity tests revealed a low P-MSN-DOX toxicity in vivo, as well. Thus, P-MSN-DOX appears to be an efficacious and safe cancer treatment strategy., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Magnetic nanoparticles (MNPs) bear many intriguing properties such as superparamagnetism, high specific surface area, remarkable colloidal stability and biocompatibility, which evoke great interest and desire of exploration in biomedical applications. For the use in the complicated physiological environment, MNPs are still being developed to have the enhanced performances and down-to-earth practicality. Engineering of MNPs into hierarchical structures is thus proposed to create a new family of magnetic materials, magnetic colloidal supraparticles (MCSPs), which exhibit collective properties and unique nanomaterial characters. From a biomedical point of view, applicability of MCSPs is somewhat more distinctive in contrast to their primary MNPs, because MCSPs are amenable to modulation of secondary structure, promotion of magnetic responsiveness and ease of function design. As a result, MCSPs have been subject to intense researches in recent years, with the aim to develop outstanding composite materials for biomedical applications. In this review, we embark on an overview of foundational topics that detail the design and fabrication of MCSPs by evaporation-induced emulsion and solvothermal techniques, and continue with a guideline for modification of MCSPs with inorganic oxides and organic polymers. Particular focus is then placed on the biomedical applications of modified MCSPs. Many examples illustrate the latest progress in design of MCSP-based microspheres for magnetic resonance imaging, targeted drug delivery, sensing, and harvesting of peptides/proteins. After these detailed accounts, the current challenges and future development of researches and applications are discussed as a conclusion to the review., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

pH-sensitive poly(L-glutamic acid) grafted mesoporous silica nanoparticles (MSN-PLGA) were prepared by the surface-initiated N-carboxyanhydride polymerization method. The resultant MSN-PLGA was well dispersed in aqueous medium and showed high drug loading efficiency, superior stability, and significantly higher drug release rates. The cumulative release of doxorubicin hydrochloride (DOX) from DOX-loaded MSN-PLGA (DOX@MSN-PLGA) was pH-dependent and the release rate was much higher at pH 5.5 than that at pH 7.4. The cytotoxicity results indicated that the blank MSN-PLGA was biocompatible and the DOX@MSN-PLGA had potent in vitro cytotoxicity effect similar to free DOX. Overall, these results demonstrate that MSN-PLGA is a promising platform to build pH controlled drug delivery systems for cancer therapy., (Copyright © 2013 Elsevier B.V. All rights reserved.)

pH-responsive composite microspheres, consisting of a core of Fe₃O₄ nanoparticle, a sandwiched layer of mesoporous silica and a shell of crosslinked poly (methacrylic acid) (PMAA), were successfully synthesized via distillation precipitation polymerization. The pKa of the composite microsphere increased with the increase in the crosslinking density. Doxorubicin hydrochloride (DOX) was applied as a model drug, and the behavior of drug storage/release was investigated. The cumulative release of DOX-loaded composite microsphere in vitro showed that the drug release rate was much faster below its pKa than that of above its pKa. Because pH of most tumor tissues was lower than that of normal tissues, the pH-responsive composite microspheres are promising drug delivery system especially for cancer therapy., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In this study, hyperbranched polyamidoamine (hPAMAM) was developed as a novel non-viral gene vector for the first time. The hPAMAM was synthesized using a modified "one-pot" method. DNA was then bound to hPAMAM at different weight ratios (w(hPAMAM)/w(DNA)). The higher weight ratio could bring larger particle size and higher zeta potential of hPAMAM-DNA complexes. The encapsulated DNA was protected by hPAMAM from degradation for over 3h. Under the optimal condition, high gene transfection efficiency could be achieved in COS7 (47.47 ± 1.42%) and HEK293 (40.8 ± 0.98%) cell lines. And hPAMAM showed rather minor cytotoxicity in vitro (cell viability=91.38 ± 0.46% in COS7 and 92.38 ± 0.61% in HEK293). The hPAMAM mediated human vascular endothelial growth factor 165 (hVEGF(165)) gene transfected cells could express hVEGF(165) stably for 14 days, with the peak expression at day 2. In conclusion, hPAMAM based gene delivery was economical, effective and biocompatible, and may serve as a promising non-viral vehicle for gene therapy., (Copyright © 2011 Elsevier B.V. All rights reserved.)

pH-responsive polymer shell chitosan/poly (methacrylic acid) (CS-PMAA) was coated on mesoporous silica nanoparticles (MSN) through the facile in situ polymerization method. The resultant composite microspheres showed a flexible control over shell thickness, surface charges and hydrodynamic size by adjusting the feeding amount of MSN and the molar ratio of [-NH(2)]/MAA. The MSN/CS-PMAA composite microspheres were stable in the pH range of 5-8 as well as in the physiological saline (0.15M NaCl). Doxorubicin hydrochloride (DOX) was applied as a model drug to investigate the drug storage and release behavior. The results demonstrated that DOX could be effectively loaded into the composite microspheres. The cumulative release of DOX-loaded composite microspheres was pH dependent and the release rate was much faster at low pH (5.5) than that of pH 7.4. The cytotoxicity test by MTT assay showed that the blank carrier MSN/CS-PMAA microspheres were suitable as drug carriers. The cellular uptake of composite microspheres was investigated by confocal laser scanning microscopy (CLSM), which indicated that MSN/CS-PMAA could deliver the drugs into HeLa cell. The above results imply that the composite microspheres are a promising drug delivery system for cancer therapy., (Copyright © 2011 Elsevier B.V. All rights reserved.)

We investigated the feasibility and efficacy of hyperbranched polyamidoamine (hPAMAM) mediated human vascular endothelial growth factor-165 (hVEGF(165)) gene transfer into skeletal myoblasts for cardiac repair. The hPAMAM was synthesized using a modified one-pot method. Encapsulated DNA was protected by hPAMAM from degradation for over 120 min. The transfection efficiency of hPAMAM in myoblasts was 82.6 ± 7.0% with cell viability of 94.6 ± 1.4% under optimal conditions. The hPAMAM showed much higher transfection efficiency (P < 0.05) than polyetherimide and Lipofectamine 2000 with low cytotoxicity. The transfected skeletal myoblasts gave stable hVEGF(165) expression for 18 days. After transplantation of hPAMAM-hVEGF(165) transfected cells, apoptotic myocardial cells decreased at day 1 and heart function improved at day 28, with increased neovascularization (P < 0.05). These results indicate that hPAMAM-based gene delivery into myoblasts is feasible and effective and may serve as a novel and promising non-viral DNA vehicle for gene therapy in myocardial infarction.

New nonstoichiometric polyelectrolyte complex nanoparticles were prepared based on chitosan (CS) and polyaspartic acid sodium salt (PAsp). The physicochemical properties of the complexes were investigated by means of turbidity, dynamic light scattering, transmission electron microscopy and zeta potential. The results indicated that the slow dropwise addition of chitosan into PAsp allowed to elaborate either anionic or cationic particles in the size range of 85-300 nm with proper CS and PAsp unit molar ratios. Investigation of structural changes during the addition of CS revealed that the microstructure of the nanoparticles depended strongly on the unit molar ratio of CS to PAsp. Nanoparticles containing a hydrophilic drug, 5-fluorouracil (5FU), were prepared by mixing and absorption method. In vitro and in vivo experiment indicated that the drug-loaded CS-PAsp nanoparticles presented a sustained release of 5FU compared to the 5FU solution and the areas under curve (AUC) were increased by about four times.

Magnetite nanoparticles of Fe(3)O(4) have been found to grow into large highly branched nanostructures including nanochains and highly branched nanotrees in the solid state through a postannealing process. By varying the preparation conditions such as annealing time and temperature, the nanostructures could be easily manipulated. Changing the starting concentration of the magnetic nanoparticle solution also caused significant changes of the nanoarchitectures. When the magnetic nanoparticle concentration is low, the nanoparticles formed straight rods mainly with an average diameter of 80 nm and a length of several microns. With increasing concentration of the nanoparticles, treelike structures began to form. With further increase of the concentration, well-ordered nanostructures with the appearance of snowflakes were generated. The driving force for the formation of the highly ordered nanostructures includes interaction between the nanoparticles and interaction through surface-capping molecules. This experiment demonstrates that novel nanostructures can be generated by self-assembly of magnetic nanoparticles under the solid state.

We present a new approach for the fabrication of thermoresponsive polymer microcapsules with mobile magnetic cores that undergo a volume phase-transition upon changing the temperature and are collected under an external magnetic field. We have prepared organic/inorganic composite microspheres with a well-defined core-shell structure that are composed of a crosslinked poly(N-isopropylacrylamide) (PNIPAM) shell and silica cores dotted centrally by magnetite nanoparticles. Since the infiltration of template-decomposed products is dependent on the permeability of PNIPAM shells triggered by changes of exterior temperature, the silica layer sandwiched between the magnetic core and the PNIPAM shell was quantitatively removed to generate PNIPAM microcapsules with mobile magnetic cores by treatment with aqueous NaOH solution. For development of the desired multifunctional microcapsules, modification of the unetched silica surface interiors can be realized by treatment with a silane coupling agent containing functional groups that can easily bind to catalysts, enzymes, or labeling molecules. Herein, fluorescein isothiocyanate (FITC), which is a common organic dye, is attached to the insides of the mobile magnetic cores to give PNIPAM microcapsules with FITC-labeled magnetic cores. In this system, it can be expected that an extension of the functionalization of the cavity properties of smart polymer microcapsules is to immobilize other target molecules onto the mobile cores in order to introduce other desired functions in the hollow cage.

A controlled drug-delivery system has been developed based on mesoporous silica nanoparticles that deliver anticancer drugs into cancer cells with minimized side effects. The copolymer of two oligo(ethylene glycol) macromonomers cross-linked by the disulfide linker N, N′-bis(acryloyl)cystamine is used to cap hollow mesoporous silica nanoparticles (HMSNs) to form a core/shell structure. The HMSN core is applied as a drug storage unit for its high drug loading capability, whereas the polymer shell is employed as a switch owing to its redox/temperature dual responses. The release behavior in vitro of doxorubicin demonstrated that the loaded drugs could be released rapidly at higher temperature or in the presence of glutathione (GSH). Thus, the dual-stimulus polymer shell exhibiting a volume phase transition temperature higher than 37 °C can effectively avoid drug leakage in the bloodstream owing to the swollen state of the shell. Once internalized into cells, the carriers shed the polymer shell because of cleavage of the disulfide bonds by GSH, which results in the release of the loaded drugs in cytosol. This work may prove to be a significant development in on-demand drug release systems for cancer therapy. [ABSTRACT FROM AUTHOR]

Mesoporous silica nanoparticles (MSN) were coated by pH-responsive polymer chitosan-poly (methacrylic acid) (CS-PMAA). This nano drug delivery system showed good application prospects and the polymer-coated microspheres were promising site-specific anticancer drug delivery carriers in biomedical field. A continuous detection of pH-responsive drug delivery system in cells in situ, utilizing MSN/CS-PMAA composite microspheres, was proposed. Two kinds of different cell lines, tumor cell line (Hela) and normal somatic cells (293T), were used to investigate the behaviours of the drug loaded system in the cells. Conclusions could be drawn from the fluorescent images obtained by confocal laser scanning microscopy (CLSM), modified drug-loaded microspheres (MSN/CS-PMAA) were ingested into cells more easily, the uptake of DOX@FITC-MSN/CS-PMAA by HeLa/293T cells were performed at pH 7.4/pH 6.8, DOX was released during the ingestion process, fluorescence intensity decreased with time because of efflux transport and photo-bleaching. Fluoresence detection by flow cytometry was performed as comparison. The continuous fluorescent observation in situ could be widely used in the pH-responsive releasing process of drug delivery system in the cells. [ABSTRACT FROM AUTHOR]

Nanoscale poly(alkyl methacrylate)s including poly(methyl methacrylate), poly(ethyl methacrylate), poly(cyclohexyl methacrylate), poly(iso-butyl methacrylate) and poly(benzyl methacrylate) were prepared by a modified microemulsion polymerization procedure. NMR analysis suggested that these poly(methacrylate)s samples were higher in syndiotactic content, lower in isotactic content and the glass transition temperatures (Tgs) of them were also higher than those reported in the literature. The tacticities of the poly(methacrylate)s, beside the restricted volume effect of nanoparticles during the modified microemulsion polymerization, were mainly influenced by the reaction temperature, the lower the reaction temperature, the higher the syndiotacticity of the products. The syndiotacticity of the product decreased obviously when the polymerization was carried out at a temperature far above the Tg of the resulting polymer. It was also shown that the tacticity of the polymer was affected by the monomer structure, a monomer with the bulkier alkyl side group would liable to result in a polymer with richer syndiotacticity. Possible mechanism of rich-syndiotacticity was also discussed. [ABSTRACT FROM AUTHOR]

Nanoscale poly(cyclohexyl methacrylate) (PCHMA) particles were prepared by a modified microemulsion polymerization procedure. 13C-NMR analysis suggested that such PCHMA samples were higher in syndiotactic content (61-72% rr) and lower in isotactic content (1-3% mm). The glass transition temperatures (Tg's) of the products were also higher than that reported in the literature. The polymer properties, such as particle size, molecular weight, tacticity, and Tg were affected by the reaction conditions. The smaller the particle size, the higher the syndiotacticity, the lower the isotacticity and the greater the molecular weight, then the higher the Tg of the PCHMA samples. Possible mechanism of rich-syndiotacticity was also discussed. [ABSTRACT FROM AUTHOR]

Abstract: The ammonium glycyrrhizinate-loaded chitosan nanoparticles were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP). The particle size and zeta potential of nanoparticles were determined, respectively, by dynamic light scattering (DLS) and a zeta potential analyzer. The effects, including chitosan molecular weight, chitosan concentration, ammonium glycyrrhizinate concentration and polyethylene glycol (PEG) on the physicochemical properties of the nanoparticles were studied. These nanoparticles have ammonium glycyrrhizinate loading efficiency. The encapsulation efficiency decreased with the increase of ammonium glycyrrhizinate concentration and chitosan concentration. The introduction of PEG can decrease significantly the positive charge of particle surface. These studies showed that chitosan can complex TPP to form stable cationic nanoparticles for subsequent ammonium glycyrrhizinate loading. [Copyright &y& Elsevier]

Nanoscale poly(ethyl methacrylate) (PEMA) particles were prepared by a monomer post-added microemulsion polymerization procedure. ¹H NMR analysis suggested that the PEMA samples were rich in syndiotactic content (58-64% rr) and lower in isotactic content (4-6%mm). The glass transition temperatures (Tg's) of the products were also higher than those of the PEMA samples prepared by ordinary free-radical polymerization. The polymer properties, such as particle size, molecular weight, tacticity, and Tg were affected by the reaction conditions. The smaller the particle size, the higher the syndiotacticity, the lower the isotacticity, the greater the molecular weight, then the higher the Tg of PEMA. A possible mechanism of rich-syndiotacticity was also discussed primarily. [ABSTRACT FROM AUTHOR]

A series of hexylamine modified polysuccinimide (PSI–HA) copolymers were synthesized by aminolysis of polysuccinimide (PSI) with hexylamine. FTIR and 1H NMR measurements confirmed the structure of the copolymers and the substitution degree of the N-hexyl aspartamide units ranged from 7 to 92 mol%. Stable nanoparticles formed when the DMF solution of PSI–HA copolymers was dropped into excess water, and the particle size reduced as increasing the substitution degree. 1H NMR analysis indicated that hexyl chain and succinimide units interacted to form the hydrophobic core, while, the nanoparticles were stabilized by the amide groups which formed hydrogen bonds with the surrounding water molecules. The nanoparticles became more compact at higher temperature due to the break of hydrogen bonds between amide groups and water molecules. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) results showed that the nanoparticles were nearly spherical. Larger nanoparticles formed when the dispersion concentration increased from 0.1% to 1.0% according to the DLS and steady-state fluorescence measurements. After the nanoparticles formed in water, a sequential dilution can't influence the particles size of the nanoparticles any longer. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a simple approach was presented to prepare functional inorganic/organic composite microspheres in which the inorganic nanoparticles were encapsulated into the polyelectrolyte complexes between chitosan (CS) and poly(aspartic acid) sodium salt (PAsp). The magnetic microspheres were prepared via electrostatic interaction between the citrate groups stabilizing Fe3O4 nanoparticles and the amino groups of CS. Being taken as a kind of special polyelectrolyte with high molecular weight, the inorganic nanoparticles presented strong interaction with polyelectrolyte. By tuning the unit molar ratio of the opposite charged polyelectrolytes and the amount of Fe3O4 nanoparticles, the structure of the composite microspheres could be controlled and the dimension of microspheres ranged from 110 nm to 320 nm. Then the approach was extended to prepare luminescent-magnetic CS–PAsp microspheres by encapsulated Fe3O4 nanoparticles and CdTe quantum dots synchronously, which exhibited superior pH stability and remained strong photoluminescence properties after crosslinking. The CdTe–Fe3O4/CS–PAsp composite microspheres are potentially useful for further application in biolabeling and imaging. [Copyright &y& Elsevier]

Abstract: A modified method to prepare chitosan–poly(acrylic acid)(CS–PAA) polymer magnetic microspheres was reported in this paper. First, via self-assembly of positively charged CS and negatively charged Fe3O4 nanoparticles, magnetic CS cores with a large amount of Fe3O4 nanoparticles were successfully prepared. Subsequently, the AA monomers were polymerized on the magetic CS cores based on the reaction system of water-soluble polymer–monomer pairs. These polymer magnetic microspheres had a high Fe3O4 loading content, and showed unique pH-dependent behaviors on the size and zeta potential. From the magnetometer measurements data, the CS–PAA polymer magnetic microspheres also had superparamagnetic property as well as fast magnetic response. A continuous release of the entrapped ammonium glycyrrhizinate in such polymer magnetic microspheres occurred, which confirmed the potential applications of these microspheres for the targeted delivery of drugs. [Copyright &y& Elsevier]

A suitable carrier chitosan (CS) was used to prepare CS-Glycyrrhetic acid (GLA) nanoparticles under very mild conditions by polyelectrolyte complexation. These nanoparticles were well dispersed and stable in aqueous solution, and the physicochemical properties of which were investigated by FT-IR, dynamic light scattering, transmission electron microscope, fluorescence spectra and zeta potential. It was found that only when the weight ratio of CS to GLA was lower than 16.7, could the nanoparticles be formed. The prepared nanoparticles carried a positive charge and had the dried TEM-assessed size in the range from 20 to 30 nm. The mean hydrated diameter, size distribution and zeta potential of the nanoparticles could be controlled by some factors including the weight ratio of CS to GLA, the average molecular weight of CS and the pH value of the medium. It was also found that GLA encapsulation efficiency into the nanoparticles increased with the increase of the weight ratio of CS to GLA. The experiment of GLA release in vitro showed that the effect of CS encapsulation on GLA release was obvious and the CS-GLA nanoparticles system might be used to provide a continuous release. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:181–191, 2006 [ABSTRACT FROM AUTHOR]