PVA/κ-carrageenan/Au/camptothecin/pegylated-polyurethane/paclitaxel nanofibers against lung cancer treatment

Gold nanoparticles, paclitaxel (PTX), and camptothecin (CMPT) were loaded into the PVA/κ-carrageenan/pegylated-PU composite and core–shell nanofibers prepared by two-nozzle and coaxial electrospinning methods. The capability of composite and core–shell nanofibers was investigated for the targeted delivery of anticancer drugs in lung cancer treatment. In vitro and in vivo release of PTX and CMPT were investigated to find the release mechanism from nanofibers compared to direct administration of pristine PTX and CMPT. The mean fiber diameter for composite and core–shell nanofibers with shell feeding rates of 0.3, 0.5, and 0.7 mL h−1 was about 225, 330, 520, and 640 nm, respectively. In vivo release studies indicated that the blood concentration of CMPT and PTX for rats fed with core–shell nanofibers reached the highest values of 26.8 ± 0.04 μg mL−1, and 26.5 ± 0.05 μg mL−1 in 36 h, and 24 h and reduced slowly within 84 h, and 48 h, respectively. The maximum cytotoxicity was 75% in the presence PVA/κ-carrageenan/CMPT/Au/pegylated-PU/PTX core–shell nanofibers. In vivo antitumor activity results confirmed the synergic effect of Au, CMPT and PTX anticancer drugs on the reduction of tumor volume without change in mouse weight by the PVA/κ-carrageenan/CMPT/Au/pegylated PU/PTX core–shell nanofibers. The obtained results indicated that the simultaneous loading of CMPT and PTX anticancer drugs and Au nanoparticles is more beneficial for lung cancer treatment.


Introduction
The combination of paclitaxel (PTX) and camptothecin (CMPT) could provide several advantages over monotherapy. In previous studies, better treatment of various cancers, including lung, breast, and melanoma, is demonstrated by the co-delivery of PTX and CMPT compared to the monotherapy of PTX or CMPT1-4. For instance, the concentrations of PTX and CMPT could be controlled by their loading into the liposome. 1 Borrelli et al. 2 synthesized the squalene conjugates with PTX, CMPT, podophyllotoxin, and epothilone against A549 lung cancer cells. In other study, the combined effect of PTX and CMPT was investigated against melanoma, 3 breast, pancreatic, 4 and medullary thyroid carcinomas. 5 Chen et al. 6 attached PTX and CMPT anticancer drugs on the 2-nitroimidazole against hypoxic tumors. In another study, CMPT and PTX were conjugated with two cyclic cell-penetrating peptides to inhibit MCF-7 breast cancer cells. 7 Hariri et al. 8 investigated the targeted delivery of PTX and CMPT from a cross-linked sponge against lung cancer. The use of targeted drug delivery systems such as liposomes, 9,10 microspheres, 11,12 nanoparticles, 13,14 and nanobers [15][16][17][18] could provide the sustained delivery of anticancer drugs. k-Carrageenan, an anionic sulfonated polysaccharide, is extracted from red algae and used for biomedical applications such as food, tissue engineering and drug delivery systems. [19][20][21][22][23] Carrageenan could also interact with inorganic materials such as graphene oxide (GO), metal-organic frameworks (MOFs) and proteins. k-carrageenan, and k-carrageenan-based composites have been used in various drug delivery systems. For instance, Sun et al. 20 interacted k-carrageenan with zein nanoparticles. Javanbakht et al. 21 synthesized k-carrageenan/MOFs composite hydrogel for oral delivery. Vinothini et al. 22 used k-carrageenan-graed graphene oxide for drug delivery of DOX. Tort & Acartürk 23 investigated the capability of electrospun k-carrageenan nanobers for oral mucositis treatment. The use of nanobers prepared by electrospinning technique is an effective strategy for loading the high content of drugs due to their high porosity, high surface area, small size, good exibility, and interconnecting channels. 24 However, there are still limitations for electrospun nanobers, due to their rapid degradation over time. The various nanobers, including composite, multilayered, 25 and core-shell nanobers, 17,18 could provide the prolonged-release proles. In recent studies, the hydrophobic polymers such as poly(3-caprolactone), 26 polyurethane (PU), 27 poly(lactic acid) (PLA), 28 and poly(lactic-co-glycolic acid) (PLGA) 29 were used to increase the stability of polysaccharide nanobers in aquatic systems.
Most PUs are non-degradable and have little use in biomedical applications. On the other hand, the natural/ synthetic biodegradable polymers are stiff with low exibility or so with poor mechanical properties. To overcome these challenges, the biodegradable PUs, composed of a hard segment, so segment, and chain extender, have been introduced as one of the most popular polymers due to their low cost, high biocompatibility, and excellent efficiency for drug delivery systems. 30 The degradation rate of PUs is mainly due to the cleavage of hydrolytic bonds present in their so segments. The composition of the so segments could control the degradation rate of the PUs. The degradation rate of PUs with hydrophilic so segments such as poly(ethylene glycol) is faster than PUs with hydrophobic so segments such as polycaprolactone diol. 31 Loading of anticancer drugs into the PUs, and its derivates could increase the availability of the anticancer agents at the tumor sites, suppress the cancer cells that did not kill by the initial dose of drug 31,32 and decrease the adverse side effects. For instance, Gajbhiye et al. 33 reviewed the performance of biodegradable PU nano-constructs for the targeted delivery of anticancer drugs. Yin et al. 34 indicated that PTX molecules were released slowly from liposome-encapsulated PU scaffolds compared to PTX release from PU. Liu et al. 35 investigated the potential PU functionalized with amine, and carboxyl group micelles for incorporating of doxorubicin hydrochloride (DOX) and PTX. In previous studies, the capability of drug-loaded PU nanobers for various cancers treatment was studied by our group. 17,18,36,37 Recently, inorganic materials such as metal oxides, zeolites, MOFs and noble metals were loaded into the nanobrous matrix to increase the delivery of anticancer drugs on the surface of the cancerous tissues. Gold-based nanomaterials with various shapes, including nanoparticles, [38][39][40] nanocages, 41,42 and nanorods [43][44][45] are incorporated into the different forms of drug delivery systems for targeted delivery and imaging in cancer therapy. Gold nanoparticles (Au NPs), due to their high stability, and easier synthesis were used to improve the attachment of cancerous cells and increase the therapeutic efficacy. 46,47 In the present study, PTX and CMPT were loaded into the kcarrageenan/Au/pegylated-PU composite nanobers prepared by two-nozzle and coaxial electrospinning methods for targeted delivery of anticancer drugs against lung cancer treatment. It was hypothesized that the co-delivery of PTX and CMPT from nanobers and the use of gold nanoparticles in the nanobers structure could enhance the targeted delivery of anticancer drugs on cancerous tissues.

Preparation of core-shell solutions
The shell solution was the PTX-loaded pegylated polyurethane (PU). The pegylated polyurethane was synthesized by reacting PEG, HDI, and BDO as described previously by Yao et al. 48 10 wt% pegylated PU electrospun solution was prepared by dissolving in N,N-dimethylacetamide (DMF, Merck). To load PTX molecules into the pegylated PU, 1 and 2 mg mL À1 PTX were added into the pegylated-PU solution under sonication for 30 min.
The core solution was the CMPT/Au-loaded PVA/k-carrageenan solution. The citrate reduction of HAuCl 4 was used to synthesize Au nanoparticles. 37 2 wt% k-carrageenan (dissolved in distilled water) and 10 wt% PVA (dissolved in distilled water) were mixed under stirring for 6 h (3 : 7 v/v). To load CMPT and Au nanoparticles into the PVA/k-carrageenan solution, 2 wt% Au suspension (with respect to the PVA/k-carrageenan solution v/v) and 1, 2 mg mL À1 CMPT were added into the PVA/k-carrageenan solution under sonication for 30 min.

Preparation of composite nanobers and core-shell nanobers
To prepare PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX composite nanobers, the prepared pegylated PU/PTX and PVA/k-carrageenan/CMPT/Au solutions were separately transferred into the two syringes (needle tip: 19 gauge) and then placed at both counter sides of the cylindrical collector which was placed an aluminum foil on the collector. The applied high voltage was varied between 15 and 25 kV. Tip-collector distance was constant at 12 cm. The feeding rate was between 0.3-1 mL h À1 for both solutions to produce the PVA/k-carrageenan/ CMPT/Au/pegylated PU/PTX composite nanobers under an electrospinning time of 4 h.
To prepare the PVA/k-carrageenan/CMPT/Au/pegylated PU/ PTX core-shell nanobers, the prepared core and shell solutions were transferred into the two syringes (tip needle: 27 and 14 gauges). The voltage, tip-collector distance, and core solution feeding rate were constant at 20 kV, 12 cm, and 0.3 mL h À1 . The shell solution feeding rate varied between 0.3 and 0.7 mL h À1 .

Instrumentation
Fourier transform infrared (FTIR) analysis was implemented ranging from 500-4000 cm À1 with a resolution of 2 cm À1 on the Fourier-transform infrared spectroscopy (Brucker, Tensor 27, Germany). X-ray diffraction (XRD) analysis ranged from 5 to 80 using an X-ray diffractometer (Intel, EQUINOX3000, France). Morphology of nanoparticles and nanobers was carried out using a scanning electron microscope (SEM, AIS2100, SERON Technology, Republic of Korea) and a transmission electron microscope (TEM, H9500, Hitachi, Japan).

Drug loading efficiency
To evaluate the drug loading measurements in the nanobers, drug entrapment efficiency (DEE%) and drug loading efficiency (DLE%) were calculated as follows: DEE ð%Þ ¼ Initial drug in nanofibers À unloaded drug Initial drug in nanofibers Â 100

In vitro drug release and pharmacokinetic studies
In vitro release studies were implemented by immersion of 100 mg drug-loaded nanobers in 500 mL of phosphatebuffered saline (PBS) solutions with a rotation rate of 50 rpm at the temperature of 37 C, and pH values of 5.5 and 7.4. At preplanned times, 2 mL of aliquot was withdrawn, and 2 mL of fresh PBS was added. The nal concentrations of PTX and CMPT were determined using High-performance liquid chromatography (HPLC, Agilent 1260, USA) and UV/Vis spectrophotometer (JAS.CO V-530, Japan) at 230 nm, and 360 nm, respectively. HPLC conditions are: a reversed-phase HPLC method, column: C-18 column, mobile phase: acetonitrile, methanol and water (50 : 10 : 40, v/v), temperature: 25 C and ow rate of 1.0 mL min À1 . Experiments were repeated three times, and the results were reported as mean AE S.D. The experimental data was statistically analyzed using an analysis of variance (ANOVA) as well as a t-test (P < 0.05).

In vivo release studies
For investigating the in vivo release of PTX and CMPT from nanobers, rst, the drug-loaded nanobers were implemented into the 15 old mice with an average weight of 25 g (Tehran University) that were maintained under a maximum isolation environment for 6 weeks based on Institutional Animals Ethics Committee (94/PO/ReBi/S/1999/CPCSEA). All animal procedures were performed in accordance with the Guidelines for Care and Use of Laboratory Animals of Tehran University and approved by the Animal Ethics Committee of National Institute for Medical Research Development (NIMAD), Tehran, Iran. Then, nanobers-implemented 15 old mice were divided into ve groups of three (pure PVA/k-carrageenan/pegylated PU nanobers, PVA/k-carrageenan/Au/pegylated PU nanobers, PVA/k-carrageenan/CMPT/Au/pegylated PU core-shell nano-bers, PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX coreshell nanobers and PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX composite nanobers). The mice dose of PTX and CMPT was 5 mg kg À1 . The nanobrous scaffolds were implanted into the lower right ank of each mouse. At predetermined intervals (1, 2, 3, 6, 12, 24, 36, 48, 60, 72, 84 and 96 h), 0.5 mL of blood samples were withdrawn and were stored in a centrifuge tube. The samples were centrifuged at 5000 rpm for 5 min to separate the plasma that was frozen at À20 C until HPLC and UV assays to determine the concentrations of PTX and CMPT, respectively.

Cell viability
To investigate the biocompatibility, and cytotoxicity of nano-bers, the pure drugs and drugs-loaded nanobers were cut into akes and placed in each well of L929 murine broblast and A549 lung cancer cell lines. Cells were purchased from the Institute Pasteur of Iran, and cultured in RPMI-1640 media under 5% CO 2 and 37 C for 24, 48 and 72 h. 5 Â 10 4 cells per well were transferred in a 48-well plate and treated with 1 and 2 mg mL À1 concentrations of pure drugs and their equivalent doses of drugs-loaded nanobers. The MTT assay was implemented by using a microplate reader (Multiskan MK3, Thermo Electron Corporation, USA) at the wavelength of 570 nm. 27 Briey, the MTT assay was carried out as follows: 20 mL of MTT solution with a concentration of 5 mg mL À1 in PBS (pH 7.4) was added to each well, and then, were incubated for a further 4 h. Then, the solution was aspirated cautiously from each well. Aer treating the cells with Sorenson buffer, the optical density of each well was readied at 570 nm.

Antitumor efficiency in vivo
The tumor-bearing mice were divided into 5 groups of three. 2 Â 10 6 A549 lung cancer cells were subcutaneously injected into the le hind ank of each anesthetized mice aer isolation for 6 weeks. When the tumor volume reached 100 mm 3 , the mice were treated with nanobrous samples, and experiments were continued for 20 days. The relative tumor volume with respect to the initial volume of tumor (V 0 ¼ 100 mm 3 ) before treatment was calculated as V/V 0 . Briey, animals were anesthetized by intra-peritoneal injection of pentobarbital at 20 mg kg À1 , and a small incision was made on the skin to expose the tumor. A small incision was made into the tumor, and synthesized bers were inserted into the tumor and then the wound was closed using subcutaneous suturing. The tumor volume is calculated as length Â width Â (length + width)/2.

Characterization of nanobers
FTIR spectra of PVA, k-carrageenan, Au, CMPT, PVA/kcarrageenan/CMPT/Au, pegylated-PU, PTX, and pegylated-PU/ PTX are illustrated in Fig. 1. For pure PVA, the detected peaks at 3250 cm À1 , 2920 cm À1 , 1690 cm À1 , 1425 cm À1 , 1080 cm À1 and 887 cm À1 were assigned to the -OH stretching, CH 2 asymmetric stretching, C]O stretching, CH 2 bending, C-O stretching, and C-C stretching, respectively. For pure k-carrageenan, the observed peaks at around 3320 cm À1 , 1420 cm À1 , 1220 cm À1 , 1150 cm À1 , 930 cm À1 , and 840 cm À1 were due to the -OH stretching, C-O-H bending, O]S]O stretching, C-O-C absorption, and O-SO 3 stretching bands, respectively. The new peaks between 500-700 cm À1 aer loading Au nanoparticles into the PVA/k-carrageenan conrmed the presence of Au nanoparticles in the nanobrous matrix. The shi of carbonyl stretching vibrations correspond to the ketone groups from 1610 cm À1 to 1660 cm À1 , and the lactone groups from 1720 cm À1 to 1745 cm À1 demonstrated the interaction of CMPT molecules with nanobrous matrix. For pegylated PU, the appeared peaks at 3350 cm À1 , 2930 cm À1 , 2840 cm À1 , 2225 cm À1 , 1730 cm À1 , 1644 cm À1 , 1550 cm À1 , 1460 cm À1 , and 1105 cm À1 were related to the N-H stretching, asymmetric CH 2 stretching, symmetric CH 2 stretching, -N]C-O absorption, C]O stretching, urea absorption, N-H bending, CH 2 bending, and C-O-C absorption, respectively. The detected peaks, in the FTIR spectrum of pure paclitaxel, at 3630 cm À1 , 3095 cm À1 , 1721 cm À1 , 1650 cm À1 , 1245 cm À1 and 1078 cm À1 were due to the presence of O-H, CH 2 , C]O, C-C, C-N and C-O groups. The prominent peaks of pegylated PU and paclitaxel have overlapped.
SEM images of PVA/k-carrageenan/CMPT/Au/pegylated PU/ PTX composite nanobers under different applied voltages (15, 20 and 25 kV) and feeding rates (0.3, 0.5, and 1 mL h À1 ) are presented in Fig. 2. By increasing the applied voltage up to 20 kV, the more homogeneous bers were prepared on the collector (mean ¼ 225 nm, Fig. 2b). The higher applied voltage (25 kV) led to instability of jet solution and enhancement of ber diameter (mean ¼ 440 nm, Fig. 2c). However, an increase in the feeding rate from 0.3 to 1 mL h À1 led to increase the ber diameter from 225 nm to 470 nm. Therefore, an applied voltage of 20 kV, tipcollector distance of 12 cm and feeding rate of 0.3 mL h À1 were selected to fabricate composite nanobers for further experiments. SEM images from PVA/k-carrageenan/CMPT/Au/ pegylated PU/PTX core-shell nanobers with different shell feeding rates (0.3, 0.5 and 0.7 mL h À1 ), core feeding rate of 0.3 mL h À1 , the voltage of 20 kV, and the tip-collector distance of 12 cm are presented in Fig. 2f-h. As expected, an increase in shell feeding rate from 0.3 mL h À1 to 0.5 mL h À1 , and 0.7 mL h À1 led to increased ber diameter from 330 nm to 520 and 640 nm, respectively. The comparison of the PVA/k-carrageenan/CMPT/ Au/pegylated PU/PTX composite and core-shell nanobers indicated that the composite nanobers had a sharp distribution of bers compared with broader distribution of core-shell nanobers at studied condition. However, the non-alignment of bers was detected for both composite and core-shell nano-bers, and thus have a randomly distributed nanobrous structure for synthesized nanobers. TEM image from core-shell nanobers demonstrated the core-sheath structure of nano-bers prepared by coaxial electrospinning.

Release studies in vitro and in vivo
DEE (%) and DLE (%) are evaluated for PTX and CMPT-loaded nanobers which results are presented in Table 1(a). The higher DEE than 95% for both PTX and CMPT loaded core-shell nanobers conrmed an effective loading of anticancer drugs into the core-shell nanobers. The lower DEE and DLE for drugloaded composite nanobers compared to drugs-loaded coreshell nanobers could be attributed to the removing unattached molecule on the nanober surface. As expected, DLE was increased by increasing the initial drug content. There were no signicant differences between the DEE of 1 mg L À1 and 2 mg L À1 anticancer drugs-incorporated nanobers. The release behavior of PTX and CMPT from PVA/k-carrageenan/CMPT/Au/ pegylated PU/PTX composite and core-shell nanobers produced by various shell feeding rates is implemented under physiological pH (pH: 7.4) (Fig. 3a-c). The obtained results suggested that prepared composite bers exhibited the drug sustained-release proles for PTX and CMPT in terms of initial burst release, followed by a sustained release period for composite nanobers and a sustained release without initial burst release from core-shell nanobers. There was no signicant difference between the release behavior of 1 and 2 mg L À1 PTX and CMPT from composite nanobers. Therefore, the loading of 2 mg L À1 PTX and CMPT did not change the release pattern but different rates compared with 1 mg L À1 PTX and CMPT-loaded nanobers, and it is possible to control the release rate of PTX and CMPT from nanobers by adjusting the concentration of drugs. On the other hand, the time durations for PTX & CMPT release from core-shell nanobers with 0.3, 0.5 and 0.7 mL h À1 shell feeding rate were 60, 48, 40 h & 96, 72, 60 h, respectively. Because of higher drug loading efficiency and more sustained release F4 formulation with core-shell structure showed the best result and was selected for in vivo release   20 kV, (c) 25 kV and different feeding rates of (d) 0.5 mL h À1 , (e) 1 mL h À1 , and core-shell nanofibers with core feeding rate of 0.3 mL h À1 and shell feeding rates of (f) 0.3, (g) 0.5 and (h) 0.7 mL h À1 , (i) mean fiber diameter of synthesized nanofibers and (j) TEM image of core-shell nanofibers.
studies. The release data of PTX from composite and core-shell nanobers best described using Peppas' equation (Table 1(b)). The values of release exponent (n ¼ 0.35, 0.32 and 0.29 for CMPT) were smaller than 0.45 from core-shell nanobers which indicated that CMPT molecules were ed from the coreshell nanobers following the Fickian mechanism. The linear release achieved for CMPT release from core-shell nanobers demonstrated an excellent tting of release data with the zeroorder pharmacokinetic model. The "n" values for PTX release from both composite and core-shell nanobers and "n" values higher than 0.45 for CMPT release from composite nanobers conrmed the non-Fickian diffusion mechanism.
The in vivo PTX and CMPT (10 mg of each drug) release proles from nanobers are presented in Fig. 3d. 5 mL of 2 mg mL À1 PTX and CMPT solutions were used as control. Using pure PTX and CMPT solutions, plasma concentrations of PTX and CMPT came to their highest within 1 h and lower to average level at about 6 h for both anticancer drugs. When rats were fed with composite nanobers, the blood concentration of CMPT and PTX reached the highest values of 29.3 AE 0.05 mg mL À1 and 26.8 AE 0.03 mg mL À1 in 6 h and 12 h and reduced slowly within 24 h and 48 h, respectively. Additionally, owing to the drug concentration gradient distribution from the inner layer to shell layer and then granted by core-shell nanobers, which stores most drug in the inner layer, the curve of CMPT and PTX release from core-shell nanobers exhibited a sustained release for about 84 h and 48 h, respectively due to the continuous release of drugs from core-shell nanobers.

Cell viability
The cell viability of synthesized composite and core-shell nanobers toward L929 normal cells is implemented to investigate the biocompatibility of synthesized nanobers. The results are illustrated in Fig. 4A. The cell viability was higher than 90% for both composite and core-shell nanobers, con-rming the high biocompatibility of the synthesized nano-brous samples. The cytotoxicity of PTX and CMPT loaded-nanobers against A549 lung cancer cell lines is presented in Fig. 4B. The cancer cells were alive in the presence pure nano-bers without Au nanoparticles and anticancer drugs. A gradual decrease in the cell viability was observed aer loading Au nanoparticles into the nanobers, which indicated the anticancer activity of Au nanoparticles against A549 lung cancer cells. Whereas, the cell viability was reduced to 53%, 44% and 35% aer treating A549 cancer cell lines with nanobers containing CMPT, PTX and CMPT/PTX. The maximum cytotoxicity was about 75% in the presence PVA/k-carrageenan/CMPT/Au/ pegylated PU/PTX core-shell nanobers (both core and shell feeding rates: 0.3 mL h À1 ). The sustained release of CMPT and PTX from nanobers resulted in more cytotoxicity of core-shell nanobers than composite nanobers. In vitro cytotoxicity results showed that its inhibition effect on tumor cells by the PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX core-shell nanobers was remarkable, but the toxicity for normal cells was slight. Similar trends are reported by other researchers. 49,50 The simultaneous incorporation of Au nanoparticles and co-delivery of PTX and CMPT into the core-shell nanobers led to effective treatment of A549 lung cancer cells.

In vivo studies
The in vivo antitumor efficacy of the PVA/k-carrageenan/CMPT/Au/ pegylated PU/PTX composite and core-shell nanobers was investigated on the A549 tumor-bearing mice with an initial tumor volume of 100 mm 3 which the results of tumor volume change and the weight of mice aer treating with nanobers are presented in Fig. 5. The pure nanobers were selected as control. As shown in Fig. 5a, the maximum tumor inhibition was occurred in the presence PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX core-shell nanobers compared to pure core-shell nanobers, Au-loaded core-shell nanobers, and composite nanobers. The results indicated the synergistic effects of Au nanoparticles and anticancer drugs on tumor inhibition. Among the above four groups, the pure core-shell nanobers did not show any tumor inhibition rate aer 20 days. Furthermore, the nanobers containing PTX and CMPT presented more effective tumor inhibition than Au nanoparticles loaded-nanobers which revealed that the continuous release of CMPT and PTX from nanobers could exert a better effect on the reduction of tumor volume and enhancement of tumor inhibition. Therefore, PVA/k-carrageenan/CMPT/ Au/pegylated PU/PTX core-shell nanobers could be an effective localized delivery system for lung cancer treatment. The investigation of mice ' s body weight aer therapy revealed that no signicant change occurred for all mice aer injecting tumors for 20 days (Fig. 5b). For comparison of the capability of the synthesized core-shell nanobers for the treatment of lung cancer cells with other nanobrous scaffolds, Qiu et al. 51 prepared the mesoporous silica nanoparticles/doxorubicin hydrochloride (DOX)loaded poly(L-lactic acid) nanobers (PLLA/DOX@MSNs) against human spca-1 lung cancer cells. The maximum cell viability was 73.10%. The release trend of DOX from PLLA/DOX@MSNs composite nanober was similar to the release proles of CMPT and PTX from PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX composite nanobers (initial burst release followed by a long period of slow-release). The inhibition rate of titanocene dichloride-loaded PLLA nanobers was 68.2% (240 mg L À1 drug concentration). 52 The maximum cell viability of A549 lung cancer cells by the chitosan/PLLA/TiO 2 /DOX/GO nanober and a magnetic eld was about 82% aer 86 h. 53 Therefore, the coincorporation of Au nanoparticles and anticancer drugs into the nanobers demonstrated an optimal therapy effect on the tumor inhibition without changing the body weight.

Conclusion
In this work, Au nanoparticles, CMPT and PTX anticancer drugs were successfully incorporated into the PVA/k-carrageenan/ pegylated PU composite and core-shell nanobers. The applied voltage of 20 kV, tip-collector distance of 12 cm and  feeding rate of 0.3 mL h À1 were optimum values for the fabrication of PVA/k-carrageenan/CMPT/Au/pegylated PU/PTX composite nanobers with an average diameter of 225 nm. The mean ber diameter for core-shell nanobers produced under shell feeding rates of 0.3, 0.5, and 0.7 mL h À1 were 330, 520 and 640 nm, respectively. The higher DEE than 95% for PTX and CMPT conrmed an effective loading of anticancer drugs into the nanobers. Time durations for PTX vb. CMPT release from core-shell nanobers with 0.3, 0.5 and 0.7 mL h À1 shell feeding rates were 60, 48, 40 h vs. 96, 72, 60 h, respectively. The linear release is achieved for CMPT release from core-shell nanobers. The PTX release data of composite, core-shell nanobers and CMP release data of composite nanobers were best described using the Peppas' equation. In vivo release studies indicated that rats fed with core-shell nanobers, the blood concentration of CMPT and PTX reached the highest values of 26.8 AE 0.04 mg mL À1 and 26.5 AE 0.05 mg mL À1 in 36 h and 24 h and kept in the constant values between 36-84 h and 24-48 and nally reduced aer 84 h and 48 h, respectively. The L929 cell viability higher than 90% for both composite and core-shell nanobers conrmed the high biocompatibility of the synthesized composite and core-shell nanobrous samples. The maximum cytotoxicity was 75% in the presence PVA/kcarrageenan/CMPT/Au/pegylated PU/PTX core-shell nano-bers. In vivo antitumor efficacy results of A549 tumor-bearing mice treated with composite and core-shell nanobers demonstrated the best effect on the reduction of tumor volume and enhancement of tumor inhibition without changing the mice's weight in the presence PVA/k-carrageenan/CMPT/Au/ pegylated PU/PTX core-shell nanobers.

Conflicts of interest
There are no conicts to declare.