Controllable delivery of hydrophilic and hydrophobic drugs from electrospun poly(lactic-co-glycolic acid)/mesoporous silica nanoparticles composite mats
Botao Song,1,2Chengtie Wu,1Jiang Chang1
1State Key Laboratory of High Performance Ceramics and Super?ne Microstructure,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai200050,People’s Republic of China
2Graduate School of the Chinese Academy of Sciences,Shanghai200050,People’s Republic of China
Received18April2012;revised29June2012;accepted7July2012
Published online in Wiley Online Library(https://www.doczj.com/doc/07948109.html,).DOI:10.1002/jbm.b.32785
Abstract:Co-delivery of several drugs has been regarded as an alternative strategy for achieving enhanced therapeutic effect.In this study,a co-delivery system based on the electrospun poly (lactic-co-glycolic acid)(PLGA)/mesoporous silica nanoparticles (MSNs)composite mat was designed for the co-encapsulation and prolonged release of one hydrophilic and one hydrophobic drug simultaneously.MSNs were chosen to load the hydropho-bic model drug?uorescein(FLU)and hydrophilic model drug rhodamine B(RHB),respectively(named as RHB-loaded MSNs and FLU-loaded MSNs).Two kinds of drug-loaded MSNs were incorporated into the polymer matrix to form a?brous structure by blending electrospinning.The effect of the weight ratios for the two kinds of drug-loaded MSNs and the initial PLGA con-centrations on the drug release kinetics were systematically investigated.The results showed that both model drugs RHB and FLU maintained sustained delivery with controllable release kinetics during the releasing period,and the release kinetics was closely dependent on the loading ratios of two drug-loaded MSNs and the initial PLGA concentrations in the composite mats.The results suggest that the co-drug delivery system may be used for wound dressing that requires the combined therapy of several kinds of drugs.V C2012Wiley Periodicals,Inc.J Biomed Mater Res Part B:Appl Biomater00B:000–000,2012.
Key Words:electrospinning,hydrophilic drug,hydrophobic drug,mesoporous silica nanoparticle,sustained release
How to cite this article:Song B,Wu C,Chang J.2012.Controllable delivery of hydrophilic and hydrophobic drugs from electrospun poly(lactic-co-glycolic acid)/mesoporous silica nanoparticles composite mats.J Biomed Mater Res Part B 2012:00B:000–000.
INTRODUCTION
In the past few decades,considerable attention has been focused on the development of drug delivery systems. Although one single-drug delivery system could offer useful therapy to treat some diseases,1–4it is found that this kind of drug system has obvious disadvantages,such as drug re-sistance and high toxicity,limiting its further applications.5–8 To solve these problems,multi-drug delivery systems are attracting more attention and have been found useful to overcome drug resistance and minimize potential toxicities by harnessing several kinds of drugs.The multi-drug delivery system loaded with hydrophobic and hydrophilic drugs simultaneously has great potential application in wound heal-ing.For example,Thakur et al.fabricated a dual-drug loaded electrospun mat containing an anesthetic,lidocaine hydro-chloride(hydrophilic drug),and an antibiotic,mupirocin (hydrophobic drug).The results demonstrated that the two drugs had the synergistic effects on treating the disease.One was to relieve the patient’s pain and the other was to kill the bacteria.Moreover,the addition of the hydrophilic drug could manipulate the release behaviors of the hydrophobic one, and this co-delivery system could be used to treat wounds.9 Recently,several delivery systems,including micelles,10 mesoporous silica-based nanocomposites,11and electrospun mats,12have been designed for the co-encapsulation and sustained release of two kinds of drugs.Among these co-delivery systems,electrospun mats are promising as drug carriers which offer site-speci?c delivery of drugs to the tar-get in human body and may be used for wound healing and cancer therapy.13–15Previously,Su et al.16prepared dual-drug loaded electrospun mats by emulsion electrospinning and they demonstrated that this system could release two hydrophilic drugs with sustained pro?les.However,this sys-tem could only load two kinds of hydrophilic drugs,which limited their application because both hydrophobic and hydrophilic drugs were needed together in many clinical cases,especially for the cancer treatments.17To the best of our knowledge,there are few reports about the
Correspondence to:J.Chang;e-mail:jchang@https://www.doczj.com/doc/07948109.html,
Contract grant sponsor:Natural Science Foundation of China;contract grant numbers:30730034,81190132
Contract grant sponsors:Strategic Priority Research Program of the Chinese Academy of Sciences and One Hundred Talent Program,SIC-CAS; contract grant number:XDA01030304
V C2012WILEY PERIODICALS,INC.1
development of drug-delivery systems by using electrospun mats for co-delivery of both hydrophobic and hydrophilic drugs with controllable release kinetics.
Mesoporous materials,especially the mesoporous silica nanoparticles (MSNs),have raised much interest in prepara-tion of drug delivery systems because of their large surface areas and porous interiors which can be used as reservoirs for loading both hydrophilic and hydrophobic drugs.18–24In addition,MSNs were reported to be able to enhance the disso-lution of the poorly water-soluble drugs and increase their bi-oavailability.25Considering the signi?cant advantages of MSNs for drug delivery,we had previously prepared a dual-drug loaded poly(lactic-co -glycolic acid)(PLGA)/MSNs electrospun mat for releasing two drugs with signi?cantly different releas-ing rates,in which the hydrophilic drug rhodamine B (RHB)was loaded into MSNs with a sustained release and the hydro-phobic drug ?uorescein (FLU)was loaded in PLGA matrix with a burst release.26Although this system could release two kinds of drugs,it was dif?cult to control their simultaneous release.As we mentioned before,it was needed to deliver two kinds of drugs in a controllable way clinically.To satisfy this requirement,in this study,a novel co-delivery carrier with controlled release of two drugs was designed,combining the electrospinning technique and the drug loading capacity of MSNs for both hydrophilic and hydrophobic drugs.Two dyes,RHB,which was easily soluble in water,and FLU,which was practically insoluble in water,were chosen because they were cheap and stable model drugs for investigation.10,27–29The two drugs were loaded into MSNs ?rst,and then the two kinds of drug-loaded MSNs were incorporated into the ?brous mat by blending electrospinning (Figure 1).The effects of the loading ratios of the two kinds of drug-loaded MSNs and the initial PLGA concentrations on the release kinetics of two drugs were systematically investigated.
MATERIALS AND METHODS
Materials
PLGA (M W ?150,000,lactic acid:glycolic acid ?90:10)was purchased from Jinan Daigang Bio-technology Co.(China).
Tetraethyl orthosilicate (TEOS),cetyltrimethylammonium bromide (CTAB),and hydrochloric acid (HCl,36–38%)were obtained from Shanghai Lingfeng Chemistry Co.(China).Am-monium ?uoride (NH 4F),RHB,FLU,N,N -dimethylformamide (DMF),and tetrahydrofuran (THF)were all purchased from Sinopharm Chem.Reagents Co.Anhydrous ethanol was pur-chased from Shanghai Zhenxing Chemical No.1Factory.Hex-a?uoroisopropanol (HFIP)was purchased from Lianyungang Tetra?uor New Materials Co.All reagents were used as received without further puri?cation.
Synthesis of MSNs
The MSNs were prepared as previously reported with some modi?cations.26Brie?y,4.0g of CTAB and 3.0g of NH 4F were dissolved into 500mL H 2O under 80 C,and then 20mL TEOS was added dropwise into the above solution.The reaction was maintained for 2h.The synthesized nanopar-ticles were then centrifuged and further extracted in a mix-ture of 4mL concentrated HCl and 200mL ethanol three times under 90 C to remove the surfactant.The obtained MSNs were ?nally dried in the oven at 60 C for 8h and then preserved in the refrigerator at 5 C for the further use.Fabrication of RHB-loaded MSNs and FLU-loaded MSNs To prepare RHB-loaded MSNs,1.0g MSNs were soaked into 100mL deionized water containing 100mg of RHB,stirring in the dark place for 24h.Then the suspension was centri-fuged and washed using distilled water to remove the RHB molecules adsorbed on the external surface of MSNs.Finally,the RHB-loaded MSNs were separated by centrifugation and then dried at 60 C for 12h to reach a constant weight.
To prepare FLU-loaded MSNs,1.0g MSNs were mixed with 500mg FLU in 100mL anhydrous ethanol and stirred in the dark place for 24h.The mixture was centrifuged and washed with anhydrous ethanol.Finally,the FLU-loaded MSNs were separated by centrifugation and then dried at 60 C for 12h to reach a constant weight.
The amount of RHB and FLU loading into the MSNs was measured by determining their corresponding concentration difference in the loading medium before and after loading.The drug loading capacity was calculated from the following equation:
Drug loading capacity ?eweight of loaded drug in MSNs =
weight of MSNs T
Fabrication of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mat
Two kinds of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mat were prepared and the composition of the electrospinning solution was listed in Table I.To investigate the effect of RHB-loaded MSNs and FLU-loaded MSNs load-ing ratios on drug delivery,the electrospun composite mats with different RHB-loaded MSNs and FLU-loaded MSNs loading ratios were prepared.Two kinds of the drug-loaded MSNs with different weight ratios (100/0;80/20;
50/50;
FIGURE 1.Schematic illustration of the process of fabrication of drug loaded electrospun PLGA/MSNs composite ?ber.[Color ?gure can be viewed in the online issue,which is available at https://www.doczj.com/doc/07948109.html,.]
2SONG,WU,AND CHANG HYDROPHILIC AND HYDROPHOBIC DRUGS FROM PLGA
20/80;0/100)were?rst ultrasonically dispersed into the mixed solvent of 1.5mL DMF and0.5mL THF for10 seconds,then0.6g PLGA was added and stirred to form a homogeneous suspension.
For fabrication of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mat with different initial PLGA concentra-tions,the same weight of RHB-loaded MSNs and FLU-loaded MSNs were?rst dispersed into HFIP with different volume (2,4,and6mL),and then0.6g PLGA was added and stirred to form a spinable suspension.
The electrospinning conditions were conducted as fol-lows.The feeding rate of the solution was?xed at2mL/h. The applied voltage on the needle of the syringe was con-trolled at13kV,and the distance between the tip of the needle and the collector was15cm.All the electrospinning procedures were performed in the dark place to avoid bleaching.30,31
Characterization
The morphology observation was performed using a?eld emission scanning electron microscope(FESEM,JEOL JSM-6700F,Japan)operated at an accelerating voltage of10kV and a?eld emission transmission electron microscope (FETEM,JEM-2100F,JEOL,Japan).Nitrogen sorption iso-therms were measured with an accelerated surface area and porosimetry system(Micromeritics ASAP2010,USA).One hundred randomly selected?bers from the SEM image (2500?magni?cation)were measured and analyzed using image analysis software(Nano Measurer 1.2software)to obtain the?ber size distribution.In vitro drug release
The in vitro drug release studies were performed in phos-phate-buffered saline(PBS,pH?7.4)at37 C over a324h period.The two kinds of drug-loaded MSNs(50mg)were incubated in5mL PBS.At the same time,the drug-loaded electrospun mats were cut into square pieces of3.0?3.0 cm2and immersed into5mL PBS.At predetermined time intervals,1mL of the release buffer was removed for analy-sis and replaced with the same volume of fresh PBS.Both the concentration of RHB(at an optical wavelength of553 nm)and FLU(at an optical wavelength of491nm)that remained in the buffer solution was determined using microplate spectrophotometer.The cumulative release dose was calculated based on the standard curve and the data were expressed as mean6standard deviation(n?3).
After incubation in PBS for324h,the composite mat was taken out and rinsed with abundant distilled water to remove residual buffer salts and then freeze-dried for more for24h to completely remove the residual water.Finally, the morphological change was observed by SEM.
RESULTS
The morphology and structure of MSNs,RHB-loaded MSNs,and FLU-loaded MSNs
Figure2(A,B)showed the SEM and TEM images of the syn-thesized MSNs.The MSNs generally had round shape and uniform size of100nm,and the nanoporous channels were also clearly observed in the inner of MSNs.The N2adsorp-tion-desorption isotherm con?rmed the well-ordered meso-structure of MSNs[Figure2(C)].As shown in Table II,the
TABLE I.The Composition of the Electrospinning Solution
No.
PLGA
Content(g)Solvent
Weight of FLU-Loaded
MSNs(g)
Weight of RHB-Loaded
MSNs(g)Ratios a
10.6 1.5mL DMF and0.5mL THF0.150100/0
0.6 1.5mL DMF and0.5mL THF0.120.0380/20
0.6 1.5mL DMF and0.5mL THF0.0750.07550/50
0.6 1.5mL DMF and0.5mL THF0.030.1220/80
0.6 1.5mL DMF and0.5mL THF00.150/100 20.62mL HFIP0.0750.07550/50
0.64mL HFIP0.0750.07550/50
0.66mL HFIP0.0750.07550/50
a The weight ratio of FLU-loaded MSNs and RHB-loaded
MSNs.
FIGURE2.(A)SEM,(B)TEM images,and(C)nitrogen isotherms of MSNs(insert:pore size distribution).
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MSNs possessed BET surface area of182.89m2/g,average nanopore size of2.62nm,and pore volume of0.48cm3/g. After loaded with model drugs FLU and RHB,the BET sur-face area,the pore size,and the pore volume signi?cantly decreased when compared with the MSNs before drug load-ing(Table II),which indicated that the FLU and RHB molecules were well encapsulated into the mesopores of MSNs.32In addition,the amount of FLU and RHB loaded into the MSNs were also measured,and the loading capacity of MSNs for FLU and RHB were15.78mg/g and24.26mg/g, respectively.
The morphology of drug-loaded electrospun
composite mat
The morphology and diameter distribution of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mats with dif-ferent RHB-loaded MSNs and FLU-loaded MSNs weight ratios were shown in Figure3.It could be observed that some drug-loaded MSNs were located near the outside sur-face of the?bers.In addition,as shown in Figure3(C,F,I, L,and O),the average diameters of the?ve kinds of com-posite?bers were in the range of700–800nm.
TABLE II.The Structure Parameters of MSNs,RHB-Loaded MSNs and FLU-Loaded MSNs,and the Drug Loading Capacity
Samples S BET
(m2/g)
D P
(nm)
V P
(cm3/g)
Drug-Loading
Capacities
(mg/g)
MSNs182.89 2.620.48–
RHB-loaded MSNs113.44<2.00.2724.26
FLU-loaded MSNs165.87 2.430.39
15.78
FIGURE3.SEM images of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mats with different RHB-loaded MSNs/FLU-loaded MSNs((A, B)100/0;(D,E)80/20;(G,H)50/50;(J,K)20/80;(M,N)0/100),and the corresponding diameter distributions(C;F;I;L;and O).[Color?gure can be viewed in the online issue,which is available at https://www.doczj.com/doc/07948109.html,.]
4SONG,WU,AND CHANG HYDROPHILIC AND HYDROPHOBIC DRUGS FROM PLGA
The PLGA-based electrospun composite mats with differ-ent initial PLGA concentrations were fabricated and the morphology was shown in Figure 4.It was observed that the prepared ?bers had homogeneous ?brous structures,and the diameters were about 360nm,590nm,and 1680nm,respectively.The increased ?ber diameter was attrib-uted to the greater molecular chain entanglement.33
The cumulative releases of FLU and RHB from composite mats
The drug release pro?les of RHB and FLU from electrospun mats with different weight ratios of RHB-loaded MSNs and
FLU-loaded MSNs were evaluated.Moreover,the drug release behaviors of both RHB-loaded MSNs and FLU-loaded MSNs were measured as controls (Figure 5).The results showed that the drugs from the naked MSNs released rap-idly in the ?rst 24hours followed by a sustained release manner.In comparison with the drug-loaded MSNs,the PLGA/MSNs composite mat showed a decreased burst release and more prolonged release for both RHB and FLU.The cumulative release of RHB from the composite mats with the RHB-loaded MSNs/FLU-loaded MSNs of 100/0,80/20,50/50,and 20/80were 40,33,24,and
11%,
FIGURE 4.SEM images of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mats with different initial PLGA concentrations ((A,B)0.1g/mL;(D,E)0.15g/mL;(G,H)0.3g/mL),and the corresponding diameter distributions (C,F,and I)(RHB-loaded MSNs/FLU-loaded MSNs ?50/50).[Color ?gure can be viewed in the online issue,which is available at
https://www.doczj.com/doc/07948109.html,.]
FIGURE 5.In vitro release pro?les of RHB (red line tred symbol)and FLU (blue line tblue symbol)from drug-loaded electrospun mats with different mass ratio of RHB-loaded MSNs/FLU-loaded MSNs (100/0;80/20;50/50;20/80;and 0/100).[Color ?gure can be viewed in the online issue,which is available at
https://www.doczj.com/doc/07948109.html,.]FIGURE 6.In vitro release pro?les of RHB (red line tred symbol)and FLU (blue line tblue symbol)from drug-loaded electrospun mats with different initial PLGA concentrations (0.1g/mL;0.15g/mL;and 0.3g/mL)(RHB-loaded MSNs/FLU-loaded MSNs ?50/50).[Color ?gure can be viewed in the online issue,which is available at https://www.doczj.com/doc/07948109.html,.]
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respectively,which indicated that the RHB release rates decreased with the decrease of the amount of RHB-loaded MSNs in the composites.Meanwhile,the cumulative release of FLU could reach about 23%,38%,43%,and 54%,respec-tively,which demonstrated that the FLU release rates increased with the increase of the amount of FLU-loaded MSNs in the composites.
Figure 6showed the cumulative release of RHB and FLU from the dual drug-loaded electrospun mat with different initial PLGA concentrations.Both FLU and RHB released with slow release kinetics.After released by 324h,the cu-mulative release of RHB was 37,29,and 15%,respectively,when the PLGA concentrations increased from 0.1and 0.15g/mL to 0.3g/mL.Similar pro?le was observed for FLU and
its release percentage was 48,39,and 25%,respectively.It was suggested that the releasing amount of both drugs decreased with the increase of initial polymer concentra-tions.Moreover,the results also demonstrated that,when same amount of RHB-loaded MSNs and FLU-loaded MSNs (50/50)incorporated in the mats,the release rate of FLU was a little faster than RHB.
The morphology of drug-loaded electrospun composite mat after releasing
The morphology of the electrospun composite mats after being immersed in PBS for 324h was shown in Figure 7.It was clear to see that the average diameters of the ?ber in all the samples were increased because of the relaxation
of
FIGURE 7.SEM images of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mats with different RHB-loaded MSNs/FLU-loaded MSNs ratios after being incubated in PBS for 324h [(A,B)100/0;(D,E)80/20;(G,H)50/50;(J,K)20/80;(M,N)0/100],and the corresponding diameter distributions (C;F;I;L;and O).[Color ?gure can be viewed in the online issue,which is available at https://www.doczj.com/doc/07948109.html,.]
6SONG,WU,AND CHANG HYDROPHILIC AND HYDROPHOBIC DRUGS FROM PLGA
polymer chain,34and the polymer chain relaxation allowed water molecules to permeate into the polymer matrix,the hydrophilic drug RHB was easily dissolved and released.In addition,previous works had found that MSNs could enhance the dissolution of poorly water-soluble drugs because of the support of both their high speci?c surface area and phase maintenance of amorphous drugs.25Thus,after water penetration into the polymer ?ber,more hydro-phobic drugs could be dissolved and released.Therefore,FLU release from MSNs in polymer ?bers might also be improved by water penetration.Similar results were also found by incubation of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mats with different initial PLGA concen-trations for 324h (Figure 8).
DISCUSSION
In a previous study,we fabricated a dual-drug loaded PLGA/MSNs electrospun mat for releasing two drugs with different release pro?les.Although this system could release two kinds of drugs in different rates,the release rate of two drugs,in particular,the release of the drug loaded in the polymer matrix,could not be well controlled.It is known that the delivery of two different drugs in a controllable way may be required clinically.Therefore,in this study,a novel co-delivery carrier was designed,and this carrier was able to load both hydrophobic and hydrophilic drugs simul-taneously.Moreover,the release pro?les of both drugs could be easily controlled by adjusting weight ratios of two drug-loaded MSNs and the initial PLGA concentrations.
As mentioned above,the weight ratios of RHB-loaded MSNs and FLU-loaded MSNs played an important role in controlling
the release of the two drugs.The FLU or RHB release rate increased with the increase of its corresponding loading ratio in the electrospun composite mat.It is easy to understand that,as the ratio of RHB-loaded MSNs/FLU-loaded MSNs increased in the composites ?bers,more RHB-loaded MSNs were exposed to the surface of PLGA ?bers,and RHB in those MSNs was easy to diffuse into medium,resulting a quick release of RHB,35whereas only a few FLU-loaded MSNs were exposed to the sur-face of PLGA ?bers,leading to a slow release of FLU.Therefore,it is speculated that the amount of drug-loaded MSNs may directly in?uence their distribution in PLGA ?bers,and thus the release kinetics of two drugs was closely associated with the amount of drug-loaded MSNs in the PLGA ?bers.
Besides the weight ratios of two drug-loaded MSNs,we also found that the initial PLGA concentrations greatly in?u-enced the release kinetics of two drugs.A higher concentra-tion of PLGA resulted in an electrospun ?ber with higher thickness.Thus,the diffusion kinetics of two drugs through the PLGA matrix was slowed down because of the increase of the polymer density,leading to a more sustained release of two drugs.36,37
Interestingly,it was found that under the same weight ratio of two MSNs in the mats,the release rate of FLU was a little faster than RHB.Previous studies showed that the interaction between the MSNs and the drug molecules,such as hydrogen bond and the electrostatic absorption might play the main role to in?uence the drug release pro?les.38,39Therefore,both hydrogen bond and electrostatic interaction might in?uence the release of both RHB and FLU in our study.However,further study will be conducted to investi-gate the drug release mechanism in the
future.
FIGURE 8.SEM images of PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mats with different initial PLGA concentrations after being incubated in PBS for 324h [(A,B)0.1g/mL;(D,E)0.15g/mL;(G,H)0.3g/mL)(RHB-loaded MSNs/FLU-loaded MSNs ?50/50),and the corre-sponding diameter distributions (C,F,and I).[Color ?gure can be viewed in the online issue,which is available at https://www.doczj.com/doc/07948109.html,.]
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Finally,we further found that the average diameters of PLGA?bers in mats increased signi?cantly after release of drugs as a result of the relaxation of polymer chain(Figures 7and8).Previous studies suggested that the relaxation of polymer chain could result in quick release of drugs.40,41 However,in this study,it was found that,although the poly-mer chain relaxed,the releases of the two drugs still main-tained sustained release kinetics from composite mats. When compared with the polymer chain relaxation,the re-tardation of the mesopores of the MSNs and the PLGA ma-trix was more obvious than that of polymer chain relaxation for controllable drug release.Therefore,it was speculated that the drug release might be mainly dominated by diffu-sion and the relaxation of polymer chain was favor for diffusion.
CONCLUSIONS
In this work,a co-delivery system,the PLGA/RHB-loaded MSNs/FLU-loaded MSNs electrospun mat,was successfully fabricated and the release pro?les from this system were systematically investigated.The results showed that release kinetics of FLU and RHB were closely associated with the weight ratio of RHB-loaded MSNs and FLU-loaded MSNs. The FLU or RHB release rate increased with the increase of its corresponding weight ratio in the electrospun composite mat.In addition,the initial PLGA concentrations were of great importance to control the release kinetics of two drugs simultaneously.With the increase of PLGA concentra-tions,the release rate decreased.The results suggested that the co-delivery system based on PLGA/MSNs mats was an excellent carrier for controllable delivery of two drugs with one was hydrophilic and the other hydrophobic.The PLGA/ MSNs electrospun mats loaded with proper drugs may be used for wound dressing application.
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Present a written argument or case to an educated reader with no specialist knowledge of the following topic. In 2016, Google’s AlphaGo defeated Lee Sedol, the World Go Champion, 4 to 1 in a five-game match. The machine’s sweeping victories have once again made AI（artificial intelligence）a hot topic. Some people fear that AI will eventually get out of control. To what extent do you agree or disagree with the opinion？Give reasons for your answer and include any relevant examples from your own knowledge or experience. A lphaGo’s great triumph over Lee Sedol once again draw s persons’ attention to artificial intelligence. And some people assert that AI will pose a threat to human existence if human lose control of it. In my opinion, it will be a long time before artificial intelligence has consciousness itself, not to mention defying human. But in the more distant future, we have reasons to believe that AI will have no distinction from human and disobey human’s orders. Artificial intelligence, in essence, is simulation of human ways of thinking. And its development deals with interdisciplinary of computer
人工智能英文版论文 人工智能(AI)系统被认为是神经网络，可以识别图片，翻译，甚至精通古老的游戏。以下是精心整理的人工智能英文版论文的相关资料，希望对你有帮助! 人工智能英文版论文篇一Google's AI Reasons Its Way around the London Underground 谷歌人工智能推导出环绕 伦敦地铁系统的路线 DeepMind‟s latest technique uses external memory to solve tasks that require logic and reasoning;a step toward more humanlike AI 维和推理能力的任务 By Elizabeth Gibney, Nature magazine on October 14, 2016 伊丽莎白.吉布尼2016年10月14日发表于《自然》杂志 深度思维最新技术使用了外部存储来解决需要逻辑思 Artificial-intelligence (AI) systems known as neural networks can recognize images, translate languages and even master the ancient game of Go. But their limited ability to
represent complex relationships between data or variables has prevented them from conquering tasks that require logic and reasoning. 人工智能(AI)系统被认为是神经网络，可以识别图片，翻译，甚至精通古老的游戏。但他们描绘数据或变量之间的复杂关系的能力有限，这妨碍了他们克服需要逻辑思维和推理能力的任务。 In a paper published in Nature on October 12, the Google-owned company DeepMind in London reveals that it has taken a step towards overcoming this hurdle by creating a neural network with an external memory. The combination allows the neural network not only to learn, but to use memory to store and recall facts to make inferences like a conventional algorithm. This in turn enables it to tackle problems such as navigating the London Underground without any prior knowledge and solving logic puzzles. Though solving these problems would not be impressive for an algorithm programmed to do so, the hybrid system manages to accomplish this without any predefined rules. 在10月12日《自然》杂志中发表的一篇论文中，谷歌在伦敦的子公司深度思维展示了他们通过结合外部存储创造了一个神经网络，来进一步克服这些障碍。这种和外部存储的结合不仅允许神经网