In vitro Evaluation of Doxorubicin‐Incorporated Magnetic Albumin Nanospheres

Magnetic albumin nanospheres that incorporate doxorubicin (M‐DOX‐BSA‐NPs) were prepared previously by our research group to develop magnetically responsive drug carrier system. This nanocarrier was synthesized as a drug delivery system for targeted chemotherapy. In this work, cytotoxic effects of doxorubicin (DOX)‐loaded/unloaded or magnetic/non‐magnetic nanoparticles and free DOX against PC‐3 cells and A549 cells were determined with the MTT test and the results were compared with each other. DOX‐loaded magnetic albumin nanospheres (M‐DOX‐BSA‐NPs) were found more cytotoxic than other formulations. The quantitative data obtained from flow cytometry analysis further verified the higher targeting and killing ability of M‐DOX‐BSA‐NPs than free DOX on both of the cancer cell lines. Additionally, the results of cell cycle analysis have showed that M‐DOX‐BSA‐NPs affected G1 and G2 phases. Finally, cell images were obtained using spin‐disk confocal microscopy, and cellular uptake of M‐DOX‐BSA‐NPs was visualized. The findings of this study suggest that M‐DOX‐BSA‐NPs represent a potential doxorubicin delivery system for targeted drug transport into prostate and lung cancer cells.     

Liver Cancer Targeting of Doxorubicin with Reduced Distribution to the Heart Using Hematoporphyrin-Modified Albumin Nanoparticles in Rats

Purpose  

To evaluate the usefulness of hematoporphyrin (HP)-modification of the surface of doxorubicin (DOX)-loaded bovine serum albumin (BSA) nanoparticles (NPs) in the liver cancer-selective delivery of DOX.     

Improved drug targeting of cancer cells by utilizing actively targetable folic acid-conjugated albumin nanospheres

Folic acid-conjugated albumin nanospheres (FA-AN) have been developed to provide an actively targetable drug delivery system for improved drug targeting of cancer cells with reduced side effects. The nanospheres were prepared by conjugating folic acid onto the surface of albumin nanospheres using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as a catalyst. To test the efficacy of these nanospheres as a potential delivery platform, doxorubicin-loaded albumin nanospheres (DOX-AN) and doxorubicin-loaded FA-AN (FA-DOX-AN) were prepared by entrapping DOX (an anthracycline, antibiotic drug widely used in cancer chemotherapy that works by intercalating DNA) into AN and FA-AN nanoparticles. Cell uptake of the DOX was then measured. The results show that FA-AN was incorporated into HeLa cells (tumor cells) only after 2.0 h incubation, whereas HeLa cells failed to incorporate albumin nanospheres without conjugated folic acid after 4.0 h incubation. When HeLa cells were treated with the DOX-AN, FA-DOX-AN nanoparticles or free DOX, cell viability decreased with increasing culture time (i.e. cell death increases with time) over a 70 h period. Cell viability was always the lowest for free DOX followed by FA-DOX-AN4 and then DOX-AN. In a second set of experiments, HeLa cells washed to remove excess DOX after an initial incubation for 2 h were incubated for 70 h. The corresponding cell viability was slightly higher when the cells were treated with FA-DOX-AN or free DOX whilst cells treated with DOX-AN nanoparticles remained viable. The above experiments were repeated for non-cancerous, aortic smooth muscle cells (AoSMC). As expected, cell viability of the HeLa cells (with FA receptor alpha, FRα) and AoSMC cells (without FRα) decreased rapidly with time in the presence of free DOX, but treatment with FA-DOX-AN resulted in selective killing of the tumor cells. These results indicated that FA-AN may be used as a promising actively targetable drug delivery system to improve drug targeting to cancer cells.     

Folate-mediated poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) nanoparticles for targeting drug delivery

A novel targeting drug delivery system (TDDS) has been developed. Such a TDDS was prepared by W₁/O/W₂ solvent extraction/evaporation method, adopting poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) [P(HB-HO)] as the drug carrier, folic acid (FA) as the targeting ligand, and doxorubicin (DOX) as the model anticancer drug. The average size, drug loading capacity and encapsulation efficiency of the prepared DOX-loaded, folate-mediated P(HB-HO) nanoparticles (DOX/FA–PEG–P(HB-HO) NPs) were found to be around 240 nm, 29.6% and 83.5%. The in vitro release profile displayed that nearly 50% DOX was released in the first 5 days. The intracellular uptake tests of the nanoparticles (NPs) in vitro showed that the DOX/FA–PEG–P(HB-HO) NPs were more efficiently taken up by HeLa cells compared to non-folate-mediated P(HB-HO) NPs. In addition, DOX/FA–PEG–P(HB-HO) NPs (IC₅₀ = 0.87 μM) showed greater cytotoxicity to HeLa cells than other treated groups. In vivo anti-tumor activity of the DOX/FA–PEG–P(HB-HO) NPs showed a much better therapeutic efficacy in inhibiting tumor growth, and the final mean tumor volume was 178.91 ± 17.43 mm³, significantly smaller than normal saline control group (542.58 ± 45.19 mm³). All these results have illustrated that our techniques for the preparing of DOX/FA–PEG–P(HB-HO) NPs developed in present work are feasible and these NPs are effective in selective delivery of anticancer drug to the folate receptor-overexpressed cancer cells. The new TDDS may be a competent candidate in application in targeting treatment of cancers.     

Bile acid-conjugated chondroitin sulfate A-based nanoparticles for tumor-targeted anticancer drug delivery

Chondroitin sulfate A-deoxycholic acid (CSA-DOCA)-based nanoparticles (NPs) were produced for tumor-targeted delivery of doxorubicin (DOX). The hydrophobic deoxycholic acid (DOCA) derivative was conjugated to the hydrophilic chondroitin sulfate A (CSA) backbone via amide bond formation, and the structure was confirmed by ¹H-nuclear magnetic resonance (NMR) analysis. Loading the DOX to the CSA-DOCA NPs resulted in NPs with an approximately 230 nm mean diameter, narrow size distribution, negative zeta potential, and relatively high drug encapsulation efficiency (up to 85%). The release of DOX from the NPs exhibited sustained and pH-dependent release profiles. The cellular uptake of DOX from the CSA-DOCA NPs in CD44 receptor-positive human breast adenocarcinoma MDA-MB-231 cells was reduced when co-treated with free CSA, indicating the interaction between CSA and the CD44 receptor. The lower IC₅₀ value of DOX from the CSA-DOCA NPs compared to the DOX solution was also probably due to this interaction. Moreover, the ability of the developed NPs to target tumors could be inferred from the in vivo and ex vivo near-infrared fluorescence (NIRF) imaging results in the MDA-MB-231 tumor-xenografted mouse model. Both passive and active strategies appear to have contributed to the in vivo tumor targetability of the CSA-DOCA NPs. Therefore, these CSA-DOCA NPs could further be developed into a theranostic nanoplatform for CD44 receptor-positive cancers.     

Preparation and preclinical evaluation of 131I‐trastuzumab for breast cancer

Trastuzumab that targets the human epidermal growth factor receptor type 2 (HER2) is known to benefit patients with HER2+ metastatic breast cancer. The objective was to explore the potential of ¹³¹I‐trastuzumab for treatment of breast cancers. Radioiodination of trastuzumab was carried out by chloramine‐T method, purified by using PD‐10 column, and characterized by size exclusion high‐performance liquid chromatography on a gel column. In vitro studies were carried out in HER2+ cells to determine the specificity of the radioimmunoconjugate. Uptake and retention of ¹³¹I‐trastuzumab were determined by biodistribution studies in tumor‐bearing non‐obese diabetic/severe combined immunodeficiency and normal severe combined immunodeficiency mice. The radiochemical purity (RCP) of ¹³¹I‐trastuzumab was 98 ± 0.4% with retention time of 17 minutes by high‐performance liquid chromatography. In vitro stability studies exhibited RCP of more than 90% in serum at 37°C after 120 hours of radioiodination. In vitro cell binding with ¹³¹I‐trastuzumab in HER2+ cells showed binding of 28% to 35% which was inhibited significantly, with unlabeled trastuzumab confirming its specificity. K_d value of ¹³¹I‐trastuzumab was 0.5 nM, while its immunoreactivity was more than 80%. Uptake of more than 12% and retention were observed in the tumors up to 120 hours p.i. ¹³¹I‐trastuzumab prepared in‐house‐exhibited RCP of more than 98%, excellent immunoreactivity, affinity to HER2+ cell lines and good tumor uptake thereby indicating its potential for further evaluation in HER2+ breast cancers.     

Radioimmunoimaging and targeting treatment in an immunocompetent murine model of triple‐negative breast cancer using radiolabeled anti–programmed death‐ligand 1 monoclonal antibody

The overall aim of this study was to evaluate whether iodine‐131 radiolabeled monoclonal antibody (mAb) targeting programmed death‐ligand 1 (PD‐L1) can be used for imaging of PD‐L1 expression noninvasively in vivo and playing synergistic effect combined with immunotherapy. Anti‐PD‐L1 mAb was radiolabeled with iodine‐131 (¹³¹I‐PD‐L1 mAb) and was characterized in vitro. Biodistribution and imaging in vivo were performed periodically. Therapy study was conducted in triple‐negative breast cancer–bearing BALB/c mice. As results, the labeling efficiencies of ¹³¹I‐PD‐L1 mAb reached 80% ± 3%, with radiochemical purity of 97% ± 1%. ¹³¹I‐PD‐L1 mAb preserved the capacity to bind living PD‐L1‐expressing cells specifically in vitro. Tumor radioactivity uptake of ¹³¹I‐PD‐L1 mAb was significantly higher than that of control groups. The xenografts were clearly imaged from 48 to 72 hours noninvasively after injection of ¹³¹I‐PD‐L1 mAb, while the xenografts were not imaged in control groups. Tumor growth was significantly inhibited, and median survival time was remarkably prolonged in combination therapy group compared with control groups. It was concluded that ¹³¹I‐PD‐L1 mAb can be a potential theranostic candidate for visualizing of PD‐L1 expression noninvasively and performing synergistic therapy in carcinomas.     

The vial kit formulation for preparation of no‐carrier‐added 131I‐MIBG

We have developed a new set of lyophilized kits, composed of 3 different kits, for the instant preparation of no‐carrier‐added ¹³¹I‐MIBG in the clinic. We here discussed the formulation of the kits, optimization of radiolabelling, quality control of radiolabeled ¹³¹I‐MIBG, and studies of animal biodistribution. The no‐carrier‐added (nca) ¹³¹I‐MIBG injection could be prepared within 30 minutes in the clinic with the help of the lyophilized kits. The radiochemical purity and specific activity (SA) could achieve above 98% and 6700 MBq/mg, respectively.     

Radioiodinated progesterone derivative for progesterone receptor targeting with enhanced nucleus uptake via phenylboronic acid conjugation

A novel ¹³¹I‐radiolabeled probe with aromatic boronate motif (¹³¹I‐EIPBA) was designed to target progesterone receptor (PR)–positive breast cancer with enhanced nucleus uptake. Acetylene progesterone was conjugated with pegylated phenylboronic acid via click reaction and radiolabeled with ¹³¹I to afford ¹³¹I‐EIPBA. Meanwhile, ¹³¹I‐EIPB without boronate was prepared as control agent. After determination of the lipophilicity and stability of these tracers, in vitro cell uptake studies and in vivo biodistribution in rats were performed to verify the enhanced nucleus uptake and PR targeting ability of ¹³¹I‐EIPBA. ¹³¹I‐EIPBA was obtained with moderate radiochemical yield (40.35 ± 3.52%) and high radiochemical purity (>98%). As expected, the high binding affinity (39.58 nM) of ¹³¹I‐EIPBA for PR was determined by cell binding assay. The internalization ratio of ¹³¹I‐EIPBA was remarkably higher than that of ¹³¹I‐EIPB in PR‐positive MCF‐7 cells. Furthermore, the enhanced nucleus uptake of ¹³¹I‐EIPBA (0.59 ± 0.02%) was found to be significantly higher than that of ¹³¹I‐EIPB (0.13 ± 0.01%) in MCF‐7 cells. A novel ¹³¹I‐EIPBA compound was developed for PR targeting with improved cellular nucleus uptake. Furthermore, the introduction of aromatic boronate motif provides a worthwhile strategy for enhancing the nuclear receptor targeting of tracers.     

聚水杨酸氧化还原响应型纳米载药系统的制备及体外评价

目的 将聚水杨酸(poly-salicylic acid,PSA)连接到羧甲基壳聚糖上,使其形成自组装纳米粒(nanoparticles,NPs),并进行表征和体外评价。方法 以O-羧甲基壳聚糖(O-carboxymethyl chitosan,OCMC)作为亲水骨链,通过二硫键将PSA连接在羧甲基壳聚糖上。利用核磁共振氢谱(¹H-NMR)、红外光谱(IR)确证聚合物的结构;采用超声法制备自组装NPs,并对其粒径、Zeta电位进行表征;采用芘荧光探针法测定NPs的临界聚集浓度(critical aggregation concentration,CAC);测定载DOX NPs包封率和载药量;MTT试验考察载药NPs的体外抗肿瘤活性。结果 OCMC二硫键连接PSA NPs(OCMC-SS-PSA NPs)的粒径为(148.5±2.3)nm;CAC值为(0.069 3±0.001 3)mg·mL^-1;还原响应性和pH敏感性良好。DOX/OCMC-SS-PSA NPs的粒径为(160.5±1.7)nm,载药量为(17.43±0.56)%,包封率为(89.67±1.23)%。MTT试验表明OCMC-SS-PSA NPs具有良好的生物安全性;细胞摄取试验表明DOX/OCMC-SS-PSA NPs在细胞内滞留时间更长。结论 OCMC-SS-PSA NPs粒径较小,具有良好的还原响应性、pH敏感性和生物安全性。OCMC-SS-PSA NPs可作为兼具还原响应性和pH敏感性的纳米给药系统。     

Folate-decorated poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) nanoparticles for targeting delivery: optimization and in vivo antitumor activity

Abstract

Context: Doxorubicin (DOX)-loaded folate-targeted poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) [P(HB-HO)] nanoparticles [DOX/FA-PEG-P(HB-HO) NPs] have potential application in clinical treatments for cervical cancer due to specific affinity of folate and folate receptor in HeLa cells.

Objective: The aim of this study was to develop an optimized formulation for DOX/FA-PEG-P(HB-HO) NPs, and investigate the targeting and efficacies of the nanoparticles.

Materials and methods: DOX/FA-PEG-P(HB-HO) NPs were prepared by W₁/O/W₂ solvent extraction/evaporation method, and an orthogonal experimental design [L₉ (3⁴)] was applied to establish the optimum conditions. The physico–chemical characteristics, microscopic observation and in vivo antitumor study of the nanoparticles were evaluated.

Results: The optimum formulation was obtained with DOX 10% (w/v), FA-PEG-P(HB-HO) 6.5% (w/v), PVA 3%(w/v) and oil phase/internal water phase volume ratio of 3/1. The size distribution, drug loading and encapsulation efficiency of the optimized nanoparticles were 150–350?nm, 29.6?±?2.9% and 83.5?±?5.7%, respectively. In vitro release study demonstrated that 80% of the drug could release from the nanoparticles within 11 days. Furthermore, in vitro microscopic observation and in vivo antitumor study showed that DOX/FA-PEG-P(HB-HO) NPs could inhibit HeLa cells effectively, and the tumor inhibition rate (TIR) in vivo was 76.91%.

Discussion and conclusions: DOX/FA-PEG-P(HB-HO) NPs have been successfully developed and optimized. In vitro drug release study suggested a sustained release profile. Moreover, DOX/FA-PEG-P(HB-HO) NPs could effectively inhibit HeLa cells with satisfying targeting, and reduce side effects and toxicity to normal tissues. DOX/FA-PEG-P(HB-HO) NPs were superior in terms of inhibiting HeLa tumor over non-targeted formulations therapy.     

负载阿霉素的黄芩苷纳米粒的制备及其体外性能评价

目的 制备负载阿霉素的黄芩苷纳米粒（DOX/SA-SS-BAI NPs）,并评价其体外性能。方法 构建以胱胺为连接臂的海藻酸钠–黄芩苷聚合物,并负载阿霉素,得到DOX/SA-SS-BAI NPs。对DOX/SA-SS-BAI NPs的理化性质进行表征;采用HepG2细胞进行MTT实验验证其细胞毒性。结果 DOX/SA-SS-BAI NPs粒径为（158.2±2.8）nm,PDI为（0.241±0.008）,Zeta电位为（-24.1±0.3）m V,包封率为（64.34±0.25）%,载药量为（16.22±0.06）%。体外释放显示载药纳米粒具有良好的还原响应性;MTT实验证明DOX/SA-SS-BAINPs对HepG2细胞具有良好的抑制作用;细胞摄取实验表明DOX/SA-SS-BAI NPs在HepG2细胞内较快地释放阿霉素。结论 制备的DOX/SA-SS-BAI NPs具有较好的理化性质和体外抗癌作用。     

GSH-sensitive polymeric prodrug: Synthesis and loading with photosensitizers as nanoscale chemo-photodynamic anti-cancer nanomedicine

Precisely delivering combinational therapeutic agents has become a crucial challenge for anti-tumor treatment. In this study, a novel redox-responsive polymeric prodrug (molecular weight, MW: 93.5 kDa) was produced by reversible addition–fragmentation chain transfer (RAFT) polymerization. The amphiphilic block polymer-doxorubicin (DOX) prodrug was employed to deliver a hydrophobic photosensitizer (PS), chlorin e6 (Ce6), and the as-prepared nanoscale system [NPs(Ce6)] was investigated as a chemo-photodynamic anti-cancer agent. The glutathione (GSH)-cleavable disulfide bond was inserted into the backbone of the polymer for biodegradation inside tumor cells, and DOX conjugated onto the polymer with a disulfide bond was successfully released intracellularly. NPs(Ce6) released DOX and Ce6 with their original molecular structures and degraded into segments with low MWs of 41.2 kDa in the presence of GSH. NPs(Ce6) showed a chemo-photodynamic therapeutic effect to kill 4T1 murine breast cancer cells, which was confirmed from a collapsed cell morphology, a lifted level in the intracellular reactive oxygen species, a reduced viability and induced apoptosis. Moreover, ex vivo fluorescence images indicated that NPs(Ce6) retained in the tumor, and exhibited a remarkable in vivo anticancer efficacy. The combinational therapy showed a significantly increased tumor growth inhibition (TGI, 58.53%). Therefore, the redox-responsive, amphiphilic block polymeric prodrug could have a great potential as a chemo-photodynamic anti-cancer agent.     

Engineering a folic acid-decorated ultrasmall gemcitabine nanocarrier for breast cancer therapy: Dual targeting of tumor cells and tumor-associated macrophages

Combination of passive targeting with active targeting is a promising approach to improve the therapeutic efficacy of nanotherapy. However, most reported polymeric systems have sizes above 100 nm, which limits effective extravasation into tumors that are poorly vascularized and have dense stroma. This will, in turn, limit the overall effectiveness of the subsequent uptake by tumor cells via active targeting. In this study, we combined the passive targeting via ultra-small-sized gemcitabine (GEM)-based nanoparticles (NPs) with the active targeting provided by folic acid (FA) conjugation for enhanced dual targeted delivery to tumor cells and tumor-associated macrophages (TAMs). We developed an FA-modified prodrug carrier based on GEM (PGEM) to load doxorubicin (DOX), for co-delivery of GEM and DOX to tumors. The co-delivery system showed small particle size of ～10 nm in diameter. The ligand-free and FA-targeted micelles showed comparable drug loading efficiency and a sustained DOX release profile. The FA-conjugated micelles effectively increased DOX uptake in cultured KB cancer cells that express a high level of folate receptor (FR), but no obvious increase was observed in 4T1.2 breast cancer cells that have a low-level expression of FR. Interestingly, in vivo, systemic delivery of FA-PGEM/DOX led to enhanced accumulation of the NPs in tumor and drastic reduction of tumor growth in a murine 4T1.2 breast cancer model. Mechanistic study showed that 4T1.2 tumor grown in mice expressed a significantly higher level of FOLR2, which was selectively expressed on TAMs. Thus, targeting of TAM may also contribute to the improved in vivo targeted delivery and therapeutic efficacy.     

Synthesis and biodistribution studies of iodine‐131 D‐amino acid YYK peptide as a potential therapeutic agent for labeling an anti‐CD20 antibody

A major drawback of conventionally radioiodinated monoclonal antibodies for radioimmunotherapy is in vivo dehalogenation of iodine as a result of deiodinase recognition. To solve this problem we have synthesized a YYK tri‐peptide consisting of non‐metabolizable D ‐amino acids modified with the N‐succinimidyl (N‐Succ) function. The chemical purity of the synthesized peptide as assessed by analytical high performance liquid chromatography was 95%. Labeling of the Fmoc‐D ‐Tyr(_tBu)‐D ‐Tyr(_tBu)‐D ‐Lys(Boc)‐N‐Succ was performed using the chloramine‐T method and the conventional extraction, resulting in a radiochemical yield of 50–71% and a radiochemical purity of >95%. Radioiodination of the peptide was followed by conjugation to anti‐CD20 antibody with 65–75% labeling efficiency and 90% radiochemical purity. The effect of radioiodinated peptide on the biological behavior of the conjugate was evaluated through biodistribution studies in normal Lewis rats. Thyroid and stomach levels from Rituximab labeled with [¹³¹I]‐YYK‐peptide were two‐ to four‐fold less than those with directly labeled [¹³¹I]‐Rituximab, suggesting low recognition of its D ‐iodotyrosine residue by endogenous deiodinases. The favorable in vitro/in vivo stability and biodistribution profiles suggest that this radioiodine‐labeled YYK peptide is a good candidate for further exploration of its potential clinical application. Copyright © 2009 John Wiley & Sons, Ltd.     

The chemotherapeutic potential of doxorubicin-loaded PEG-b-PLGA nanopolymersomes in mouse breast cancer model

Vesicles of mPEG-PLGA block copolymer were developed to deliver a therapeutic quantity of doxorubicin (DOX) for breast cancer treatment. The DOX-loaded nanoparticles (NPs) were prepared by the pH-gradient method and then evaluated in terms of morphology, size, DOX encapsulation efficiency and in vitro drug release mechanism.The PEG-PLGA nanopolymersomes were 134 ± 1.2 nm spherical NPs with a narrow size distribution (PDI = 0.121). DOX was entrapped in mPEG-PLGA nanopolymersomes with an encapsulation efficiency and a loading content of 91.25 ± 4.27% and 7.3 ± 0.34%, respectively. The DOX-loaded nanopolymersomes were found to be stable, demonstrating no significant change in particle size and encapsulation efficiency (EE%) during the 6-month storage period of the lyophilized powder at 4 °C. The nanopolymersomes sustained the release of DOX. In cytotoxicity studies of 4T1 cell line samples, free DOX showed a higher cytotoxicity (IC50 = 1.76 μg/mL) than did DOX-loaded nanopolymersomes (15.82 μg/mL) in vitro. In order to evaluate the antitumor efficacy and biodistribution of DOX-loaded nanopolymersomes, murine breast tumors were established on the BALB/c mice, and in vivo studies were performed. The obtained results demonstrated that the prepared drug delivery system was highly effective against a murine breast cancer tumor model and successfully accumulated in the tumor site through an enhanced permeation and retention mechanism.In vivo studies also proved that DOX-loaded nanopolymersomes are stable in blood circulation and could be considered a promising and effective DOX delivery system for breast cancer treatment.     

Radiosynthesis and preliminary biodistribution in mice of 6‐deoxy‐6‐[131I]iodo‐L‐ascorbic acid

An ascorbate analog labeled with iodine‐131, 6‐deoxy‐ 6‐[¹³¹I]iodo‐L ‐ascorbic acid was prepared for evaluation as an in vivo tracer of L ‐ascorbic acid. The no‐carrier‐added radiosynthesis was conducted by nucleophilic bromine–iodine exchange between the brominated precursor and sodium [¹³¹I]iodide in 2‐pentanone at 130–140°C. HPLC purification using a reverse‐phase column gave 6‐deoxy‐6‐[¹³¹I]iodo‐L ‐ascorbic acid in radiochemical yield of 36–60% with high radiochemical purity and satisfactory‐specific radioactivity in a total preparation time of 90 min. Biodistribution studies in fibrosarcoma‐bearing mice showed a high uptake in the adrenal glands, accompanied by low activity of tumor accumulation, accumulation properties similar to previous results obtained with ¹⁴C‐labeled ascorbic acid and 6‐deoxy‐6‐[¹⁸F]fluoro‐L ‐ascorbic acid, in spite of high level of deiodination. Copyright © 2009 John Wiley & Sons, Ltd.     

Photodynamic therapy and nuclear imaging activities of zinc phthalocyanine‐integrated TiO2 nanoparticles in breast and cervical tumors

In recent years, phthalocyanines (Pcs) have been widely used as photosensitizer in photodynamic therapy applications. Because of their strong absorptions in the near‐infrared region (640–700 nm). The integration of phthalocyanine derivatives to a nanoparticle is expected to be efficient way to improve the activity of the photosensitizer on the targeted tissue. It is known that the integrated molecules not only show better accumulation on tumor tissue but also reduce toxicity in healthy tissues. In this study, the ZnPc molecule was synthesized and integrated to the TiO₂ nanoparticle, to investigate the potential of PDT and its cytotoxicity. Additionally, ZnPc and ZnPc‐TiO₂ molecules were labeled with ¹³¹I and it was aimed to put forth the nuclear imaging/therapy potentials of ¹³¹I labeled ZnPc/ZnPc‐TiO₂ by determining in vitro uptakes in mouse mammary carcinoma (EMT6), human cervical adenocarcinoma (HeLa). In result of our study, it was observed that the radiolabeling yields of the synthesized ZnPc and ZnPc‐TiO₂ with ¹³¹I were quite high. In vitro uptake studies shown that ¹³¹I‐ZnPc‐TiO₂ could be a potential agent for nuclear imaging/treatment of breast and cervical cancers. According to PDT results, ZnPc‐TiO₂ might have as to be a potential PDT agent in the treatment of cervical tumor. ZnPc and ZnPc‐TiO₂ might be used as theranostic agents.     

Injectable Hydrogels for Localized Chemotherapy and Radiotherapy in Brain Tumors

Overall survival of patients with newly diagnosed glioblastoma (GBM) remains dismal at 16 months with state-of-the-art treatment that includes surgical resection, radiation, and chemotherapy. GBM tumors are highly heterogeneous, and mechanisms for overcoming tumor resistance have not yet fully been elucidated. An injectable chitosan hydrogel capable of releasing chemotherapy (temozolomide [TMZ]) while retaining radioactive isotopes agents (iodine, [¹³¹I]) was used as a vehicle for localized radiation and chemotherapy, within the surgical cavity. Release from hydrogels loaded with TMZ or ¹³¹I was characterized in vitro and in vivo and their efficacy on tumor progression and survival on GBM tumors was also measured. The in vitro release of ¹³¹I was negligible over 42 days, whereas the TMZ was completely released over the first 48 h. ¹³¹I was completely retained in the tumor bed with negligible distribution in other tissues and that when delivered locally, the chemotherapy accumulated in the tumor at 10-fold higher concentrations than when delivered systemically. We found that the tumors were significantly decreased, and survival was improved in both treatment groups compared to the control group. Novel injectable chemo-radio-hydrogel implants may potentially improve the local control and overall outcome of aggressive, poor prognosis brain tumors.     

Preparation of BMP-2 Containing Bovine Serum Albumin (BSA) Nanoparticles Stabilized by Polymer Coating

Purpose  The purpose of this study was to investigate the preparation process of bone morphogenetic protein-2 (BMP-2) containing bovine serum albumin (BSA) nanoparticles (NPs), and to assess the bioactivity of BMP-2 encapsulated in such NPs. Methods  The NPs were prepared by a coacervation method, and the effects of process parameters on NP size and polydispersity were examined. Polymer coated NPs were characterized with respect to amount of adsorbed polymer, particle size and zeta potential. Using bone marrow stromal cells (BMSC), biocompatibility of the NPs was investigated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) Assay, and bioactivity of the encapsulated BMP-2 was investigated by alkaline phosphatase (ALP) induction and calcification. Results  The size of NPs could be controlled in the 50–400 nm range by process parameters including BSA concentration, non-solvent:solvent ratio and pH value. After coating with cationic polymers, the particle size and zeta potential were significantly increased. MTT assay indicated no toxicity of both the uncoated and coated NPs on BMSC. Based on ALP induction and calcification, full retention of BMP-2 bioactivity was retained in the polymer-coated NPs. Conclusions  This study described a preparation procedure for BSA NPs with controllable particle size, and such polymer-coated BSA NPs are promising delivery agents for local and systemic administration of BMP-2 in bone regeneration.