Biocompatible Nanoparticles for Selective Drug Release at Cancer Cells

Chapter 10

Downloaded by UNIV OF FLORIDA on November 21, 2017 | http://pubs.acs.org Publication Date (Web): November 15, 2017 | doi: 10.1021/bk-2017-1271.ch010

Biocompatible Nanoparticles for Selective Drug Release at Cancer Cells Filiz Karagöz, Robert Dorresteijn, Klaus Müllen, and Markus Klapper* Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany *E-mail: [email protected].

The recent design and stepwise development of nanocarriers by fulfilling the mandatory requirements like biocompatibility, size, functionality and favorable surface characteristics were comprehensively described in order to demonstrate the selective drug release profile at tumor tissues. Employing nonaqueous emulsion as a tool, biocompatible polylactide nanoparticles were synthesized with an appropriate size and shape. Block copolymerization of L-lactide using a model bifunctional peptide initiator resulted in triblock copolymer nanoparticles, which were loaded with dye during the emulsion process to investigate the cargo release and cell internalization properties. Afterwards, introducing the specific cleavable peptide sequences into the particles allow us to achieve triggered drug release by Matrix MetalloProteinase-2 (MMP-2), which is an overexpressed enzyme in tumor tissues. Finally, biocompatible emulsifiers for the nonaqueous emulsion were described. They were able to change their polarity from hydrophobic to hydrophilic by irradiation and, therefore, facilitate the transfer of the particles from nonaqueous to aqueous media by light-induced processes.

© 2017 American Chemical Society Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.

Introduction


Over the past decades, the number of investigations on polymeric nanoparticles has been significantly increasing in the field of material science, nanotechnology and drug delivery (1). In particular, the development of polymer-based nanocarriers for bio-medicine is proposed for diagnosis and treatment of cancer disease. In order to achieve a successful design of nanoparticles for controlled drug delivery, certain substantial properties have to be considered simultaneously (Figure 1), namely: ○ ○ ○ ○ ○

Biocompatibility / Biodegradability Size Functionality / Targeting properties Triggered drug release Surface properties / Hydrophilization

Biocompatibility, excellent mechanical properties and being derived from renewable resources make polylactide one of the major polyesters widely applied in biological fields (2). First and foremost, polylactide has been approved by the Food and Drug Administration (3). It undergoes bulk erosion because of the ester function on the backbone and degradation mainly results in non-toxic compounds like water and carbon dioxide as hydrolysis products. Additionally, low immunogenicity increases its attractiveness as a drug carrier (4). Colloidal carrier systems can be designed with various morphologies like polymeric micelles, nanoparticles or polymersomes (5). One of the most common preparation method is the self-assembly of preformed polymers in aqueous media. Drug loading, in this case, can be achieved through physical adsorption or chemical bonding (6–8). Nevertheless; the aqueous-based methods are not applicable in the presence of water sensitive components. Under such circumstances, nonaqueous emulsion offers an ideal solution for sensitive polymerizations to obtain polyester nanoparticles through polycondensation or to obtain polyurethane nanoparticles by polyaddition reactions (9). This method is also suitable for generating well-defined polylactide-based nanoparticles by ring opening polymerization (ROP) using water and air sensitive catalysts (10). The optimal size of a nanocarrier is a crucial factor for efficient drug delivery in cancer therapy. Particles having a diameter of around 100 nm were considered to be ideal (11–13). When particles are smaller than 100 nm, they can be captured by macrophages in the reticuloendothelial system and suffer from drainage into blood capillaries. Very small particles, less than 6 nm, are quickly filtered by dialysis from the kidneys. When particles are larger than 200 nm in diameter, they can activate the human complement system and are digested by the spleen or by Kupffer cells (11–13). Tumor tissues are known to have more permeable endothelial blood vessels than normal tissues (14). Due to this better permeability, chemotherapeutics loaded nanocarriers can diffuse with higher rates specifically into the tumor cells and accumulate there (15). This type of passive targeting is known as “Enhanced Permeability and Retention Effect (EPR) (16).” For such type of mechanism, 232 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


the size of the carrier and circulating time in the blood are the driving forces. Nanoparticles possess a higher surface reactivity which increases the interaction with a lipid bilayer. This strong interaction with cell membrane results in an uptake of the drug nanocarrier (17, 18). In addition to passive targeting; other targeted delivery mechanisms used to deliver particles to cancer cells have been described. For example, using the specific receptors on cell membranes or using the special enzymes overexpressed in tumor tissues have been studied (19, 20). Polymeric nanocarriers can be specifically designed for this purpose through different approaches. One approach is the modification of the particle surfaces to covalently or electrostatically attach bio-active agents like folic acid (Vitamin B9), biotin (Vitamin B7), curcumin, selegiline, selectin, carbohydrates, antibodies or aptamers etc. (5) Another technique is based on the incorporation of specific peptide sequences that can address directly to the cancer cells. Among all of the approaches, using peptides as targeting moieties has a great advantage because of the lower negative immune system response based on the nature of peptide and easy optimization of the material’s biological activities (5). Recently, triggered drug release through cleavable peptides by proteinases have been increasingly described in literature (21, 22). Among the proteinases, one of the important classes is Matrix Metalloproteinases (MMPs), a family of zinc-dependent secreted endopeptidases, overexpressed at the invasive front of cancer cells and at sites of angiogenesis (23, 24). The overexpression of MMP can be utilized for triggered drug release in tumor tissues by using carriers bearing enzyme sensitive peptide sequences (25). Pro-Leu-Gly-Leu-Ala-Gly (PLGLAG) is one of the specific peptide sequences recognizable by MMP-2 (26). Recently, such sequences have been used to modulate the cellular uptake of quantum dots (27). Likewise, the surface of magneto-fluorescent iron oxide nanoparticles has been conjugated with a hydrophilic polymer using the MMP-2 cleavable peptide sequence as a linker. Subsequent bisection showed a selective accumulation of the nanocarrier in tumor tissues (25). Another important factor is the adjustment of the particle’s surface properties to ensure a well dispersed material sustainable in different environments. Nanocarriers formed via nonaqueous emulsion have a hydrophobic surface. For bio-applications, however, they have to be transferred into the aqueous environment without aggregation (28). The transferring is challenging, requiring a water-based second surfactant layer and difficult purification steps (29). Recently, photo-active amphiphilic copolymer micelles have been developed for easy and smart switching of the surface polarity from hydrophobic to hydrophilic (30). This concept has to be transferred to fully biocompatible block copolymers. Overall, to accomplish the essential properties needed for nanoparticles to be effectively used in drug delivery, over the years we have described the stepwise development of nanocarriers in order to obtain selective drug release at cancer cells (10, 31–33). This is now summarized in the following part.

233 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


Figure 1. Schematic illustration of required properties of nanoparticles for cancer therapy. (see color insert)

Synthesis of Poly(L-lactide) Nanoparticles Our first goal from the described list of decisive criteria for the successful design of nanocarriers is the one pot synthesis of biocompatible nanoparticles with a diameter of appropriately 100 nm. For the synthesis of polylactide, ring-opening polymerization (34) was employed due to the facile adjustability of the chain length in comparison to polycondensation (35). Although a great variety of metal catalysts (34) are used for this purpose, non-metallic ones are favored as the material is intended for biological applications. Among them, N-heterocyclic carbene derivatives are one of the most popular organocatalysts for the polymerization of lactide (36). However, due to their extremely water and air sensitive properties, polymerization has to be performed completely in a water-free and inert environment. Until now, polylactide nanoparticles have been obtained from the preformed polymers by applying different techniques like emulsification/solvent evaporation (37, 38) or nanoprecipitation (39). For the one pot synthesis, aqueous emulsion polymerization is not suitable due to the presence of water. Therefore, in our work, nonaqueous emulsion is employed for generating polylactide-based nanocarriers. As shown in Figure 2, nonaqueous emulsion consists of two nonmiscible organic solvents such as N,N′-dimethylformamide/n-hexane or acetonitrile/cyclohexane. The emulsion systems can be stabilized by amphiphilic block copolymers like poly(isoprene)-block-poly(methylmethacrylate) (PI-b-PMMA), poly(isoprene)-block-poly(ethylene oxide) (PI-b-PEO) or poly(isoprene)-block-poly(styrene) (PI-b-PS) (9, 40, 41). Poly(L-lactide) nanoparticles were prepared with a controlled molecular weight and narrow polydispersity by using the air and moisture sensitive N-heterocyclic carbene, 1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene (SIMes), as a catalyst, and 1-pyrenebutanol as an initiator in one step at ambient temperature (Figure 2 and 3) (10). 234 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


Figure 2. Nonaqueous emulsion polymerization process. (see color insert)

Figure 3. Synthesis of poly(L-lactide) by SIMes as a catalyst. Acetonitrile was determined as a suitable dispersed phase in cyclohexane to form a nonaqueous emulsion to polymerize L-lactide with controlled molecular weight and narrow polydispersity. PI-b-PEO block copolymer having a number average molecular weight of 45700 g/mol, polydispersity index (PDI) of 1.06 and a molar block composition of 55% PI and 45% PEO (DPPI = 440, DPPEO = 360) was used for the stabilization of the oil-in-oil emulsion. A concentration of 0.34 wt% or higher of the block copolymer was enough to emulsify the system efficiently with an average droplet diameter of around 72 nm, as determined by Dynamic Light Scattering (DLS) measurements (10). According to the general scheme shown in Figure 2, L-lactide was dissolved in acetonitrile and emulsified in cyclohexane by PI-b-PEO. By dropwise addition of an acetonitrile solution of SIMes and 1-pyrenebutanol to the dispersion, the polymerization proceeded completely inside of the droplets within 15 minutes. By this method, polymers with a degree of polymerization of 35, 50 and 70 were obtained with a yield of 99% according to 1H-NMR spectroscopy and Gel Permeation Chromatography (GPC). Particles were well-defined with hydrodynamic radii of around 70 nm, which was determined by DLS. Scanning Electron Microscopy (SEM) imaging revealed spherical and monomodal distributed particles with a diameter of approximately 65 nm (10). 235 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.

Polylactide-block-Peptide-block-Polylactide Nanoparticles


Although polylactide, is a commonly used material for drug delivery, it suffers from a lack of functionality. Therefore, after achieving control of particle size, we then focused on the functionalization of the nanoparticles with peptide sequences. We demonstrated the incorporation of a peptide into the polymer blocks by a single step approach (Figure 4). Polylactide-block-peptide-block-polylactide was prepared by using bishydroxy functionalized peptide (Ac-Ser-Trp-Trp-Trp-TrpTrp-Ser-NH2) as an initiator for the ring opening polymerization of L-lactide with SIMes as a catalyst (31).

Figure 4. Synthesis of polylactide-b-peptide-b-polylactide triblock copolymer via ring-opening polymerization of L-lactide by a bifunctional peptide initiator.

This peptide sequence (Ac-Ser-Trp-Trp-Trp-Trp-Trp-Ser-NH2) (Figure 5) consists of five tryptophan units and two serine end groups. The free hydroxy groups of the serine units initiate the polymerization of L-lactide, leading to the formation of ABA triblock copolymer.

Figure 5. Structure of the peptide, Ac-Ser-Trp-Trp-Trp-Trp-Trp-Ser-NH2 used for initiating the polymerization of L-lactide.



Polymerization was conducted in a nonaqueous emulsion to generate polymeric nanoparticles in one pot, using acetonitrile as the dispersed and cyclohexane as the continuous phase stabilized by PEO-b-PI. Polylactideblock-peptide-block-polylactide triblock copolymers obtained with a number average molecular weight up to 11000 g/mol were monomodal with a very narrow polydispersity (PDI= 1.13) which means both hydroxy groups of serine were involved in the polymerization without any side reactions. End group functionalization of 99% was shown by 1H-NMR (31). In the emulsion process, particles were quantitatively loaded with PMI (9-bromo-N-(2,5,8,11,15,18,21,24-octaoxapentacosan-13-yl)perylene-3,4dicarboxymonoimide) which has a high fluorescence (42) to visualize cellular uptake of the particles. The particles measured an approximate size of 80 nm as determined by DLS. SEM micrographs also showed the particles were monomodal and spherical with smooth surfaces in a similar size range (31). To investigate cell internalization, particles had to be transferred into the aqueous medium. For this hydrophilization process, 0.05−0.2 wt% LutensolAP-20, which is a PEG-based surfactant with a molecular weight of around 1050 g/mol, consists of 20 ethylene oxide repeating units with alkylphenol, was employed. After the transfer, particle diameters of around 100-120 nm were obtained by SEM. DLS analysis demonstrated that particles possessed a hydrodynamic radius of around 100-130 nm. This 20-50 nm increase in particle size after the hydrophilization, was attributed to the formation of a second surfactant shell around the particles and that could cause some minor aggregation in solution (31). Cell Uptake and Internalization Cell internalization studies were performed on HeLa cells, which were incubated for 12 hours with nanoparticles, followed by visualization using Coherent Anti-Stokes Raman Scattering (CARS) Microscopy and Two-Photon Fluorescence Microscopy (TPEF) techniques. In the three-dimensional CARS-TPEF images of the dye loaded particles (Figure 6), the red regions demonstrate the CARS response of the cell area and green dots (for example circled in yellow) come from the fluorescence response of the nanoparticles. Observing the particle signals within the cell boundries clearly shows the cellular uptake of the carriers by the HeLa cells (31).

Triblock Copolymer Nanoparticles for Selective Drug Release at Cancer Cells Stimuli-responsive drug delivery systems allow the release of a drug at the specific tumor sites. As such, the negative effects of the chemotherapautic agents on healthy tissues are alleviated. In some cases, the stimuli is caused by external effects like light, electric field or magnetic field, however, in most cases these stimuli are not as specific as internal effects like pH, concentration of ions or enyzmes (43). More effective targeting can be achieved by exploiting 237 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


the overexpression of specific enzymes in tumor tissues which allows for the enzyme-responsive drug release at the pathological region (44). To take advantage of this enzyme effect, in the following section, a special peptide sequence was incorporated into the polylactide nanoparticles to address the selective release of the drug in the tumor cells (32). Therefore, in our work the PLGLAG peptide sequence which is recognized by MMP-2 was used to obtain ABA type triblock polylactide-b-peptide-b-polylactide copolymer nanoparticles (22, 45).

Figure 6. (a, b) Lateral and axial projections of overlaid CARS (red) and TPEF (green), after 12 h incubation of the nanoparticles into the HeLa cells. Axial projections (right and below each lateral image) show the YZ and XZ localization of nanoparticle (circled in yellow) within the depth of the cell. (Reproduced from reference (31). Copyright (2013) American Chemical Society). (see color insert) PLGLAG bearing peptide sequence, Ac-Ser-Gly-Phe-Gly-Pro-Leu-GlyLeu-Ala-Gly-Gly-Phe-Gly-Ser-NH2 (Ac-SGFGPLGLAGGFGS-NH2) which has two terminal serine units with free hydroxy groups, was used to initiate the L-lactide ring-opening polymerization by SIMes. Triblock copolymers, PLLA-b-(Ac)SGFG-PLGLAG-GFGS-NH2-b-PLLA, were obtained with a number average molecular weight up to 10000 g/mol depending on the monomer to initiator ratio and with a narrow molecular weight distribution as low as 1.19 (Figure 7) (32). Degradation of the Copolymers To study the degradation, model reactions were performed by incubating the triblock copolymers, which were obtained by solution polymerizations, in MMP-2 medium for up to 4 days and analyzed by Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS). In addition, control experiments were proceeded using a Leu-Ala-Leu-Gly-Pro-Gly (LALGPG) sequence, which is not recognizable or cleavable by MMP-2 (22). MALDI-TOF-MS spectrum of cleavable and non-cleavable peptide bearing triblock copolymers before and after incubation with MMP-2 are shown in Figure 8. While the spectra of the non-cleavable peptide bearing triblock copolymer remains almost uneffected by the enzyme treatmant (bottom, blue), the corresponding spectra (top, blue) obtained for the enzyme sensitive polymer 238 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


shows a significant degradation indicated by the drop in the molecular weight. These results clearly demonstrated the selective degradation of the PLGLAG bearing triblock copolymer nanoparticles by the overexpressed enzyme, MMP-2 in cancer cells.

Figure 7. Synthesis of triblock copolymer via ring-opening polymerization of L-lactide by a special peptide initiator.

Figure 8. MALDI-TOF-MS spectra: cleavable triblock copolymer before (top, green) and after 4 days of incubation with MMP-2(top, blue); non-cleavable copolymer before (bottom, green) and after 4 days of incubation with MMP-2 (bottom, blue). (Reproduced with permission from reference (32). Copyright (2014) John Wiley and Sons). (see color insert)


Degradation of the Copolymer Nanoparticles


After confirming the selective enzyme decomposition of the polymer, triblock copolymer nanoparticles were generated via nonaqueous emulsion in the presence of a dye, PMI, or chemotherapeutic agent, 5-fluorouracil, with Ac-SGFG-PLGLAG-GFGS-NH2 and Ac-SGFG-LALGPG-GFGS-NH2 as initiators, respectively. After formation, the particles were again transferred to the aqueous medium with Lutensol AP20. DLS measurements demonstrated that the particles in the water phase had a diameter of around 100 nm and were uniformly distributed. Under the physiological conditions in 20 vol% blood serum, no aggregation was observed (32). Selective Dye Release In order to observe the enzymatic cleavage and cargo release, dye loaded nanoparticles were incubated with MMP-2. Due to the enzymatic degradation, the molecular weight of the polymeric particles dropped and the glass transition temperatures (Tg) decreased from 39 °C to 31 °C as determined by GPC and Differential Scanning Calorimetry (DSC), respectively. As a result of these physicochemical changes, the payload was released from the nanocarriers. The cargo release confirmed by Fluorescence Spectroscopy, which showed a higher dye release from the polymer carrying cleavable peptide sequence in comparison with the non-cleavable one (32). Selective Drug Release 5-Fluorouracil (5-FU) is one of the commonly used chemotherapeutic agent for different kind of cancers like breast, stomach, pancreatic etc... It was selected as a model drug for our drug release studies due to its hydrophilic nature which allowed us to make succesful encapsulation in hydrophobic environment (46, 47).

Figure 9. Cytotoxicity by 5-FU and 5-FU encapsulated nanocarriers bearing the PLGLAG or the LALGPG on C2C12 cells (Green part shows live cells and red dots show dead cells). (Reproduced with permission from reference (32). Copyright (2014) John Wiley and Sons). (see color insert) 240 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.

The cytotoxicity of 5-FU loaded cleavable and non-cleavable peptide bearing copolymer nanoparticles on C2C12cancer cells (48) expressing MMP-2, were investigated. As shown in Figure 9, after the incubation of the nanocarriers in the cancer cell media, PLGLAG bearing copolymer nanoparticles caused significant cell death. Conversely, particles containing the scrambled sequence were non-toxic. Thus, we clearly showed the selective drug release from the cleavable nanoparticle at tumor tissues.


Polarity Reversal from Hydrophobic to Hydrophilic So far, we have achieved a number of critical requirements such as biocompatibility, size and functionality to ensure the nanocarriers are appropriate delivery tool for triggered drug release at cancer cells. In order to apply the particles in biological fields, hydrophobic carriers produced by nonaqueous emulsion have to be transferred into the water-based medium without aggregation. In the previous parts of our study, we used a second surfactant layer, LutensolAP-20, for this transferring issue. This process requires additional challenging purification procedures and aggregation can still occur during the second shell formation (28, 29). This would result in the clearance of the aggregated particles from the body by Kupffer cells (11–13). To overcome this issue, we developed PEG-block-poly((1-pyrenyl methyl) glutamate, (PEG-b-PGlu(Pyr)), as a new emulsifier, which can be dispersed in nonaqueous solutions and after switching polarity by light irradiation, transferred easily into aqueous environments (33).

Figure 10. Synthesis of PEG-b-PGlu(Pyr) block copolymer.



PEG-b-PGlu(Pyr) block copolymer was synthesized as shown in Figure 10. By ring opening polymerization of γ-benzyl glutamic acid N-carboxyanhydride with PEG-NH2 (Mn=2000 g/mol) as a macroinitiator, PEG-b-Polyglutamic acid copolymer was obtained. The block ratio was confirmed by 1H-NMR as a 1:2 (PEG/PGlu) and 1H-DOSY measurements confirmed the covalent attachment of the blocks to each other. The polymer was deprotected and modified with 1pyrene methanol to hydrophobize the carboxylic acid side chains. This diblock copolymer can be dispersed in nonaqueous solutions and transferred to an aqueous environment after polarity switching by light irradiation (33). Polylactide nanoparticles were synthesized via ring-opening polymerization of L-lactide by nonaqueous emulsion which consists of acetonitrile/cyclohexane using PEG-b-PGlu(Pyr) as an emulsifier. According to DLS analysis, poly(Llactide) nanoparticles have a hydrodynamic radius of 130±19 nm. A size of around 93 nm was revealed by SEM (33).

Figure 11. Photolytic cleavage of pyrene groups.

After adding water to obtain a biphasic system, the reaction mixture was exposured to UV light (λ=366 nm, P=4 W). After three hours, hydrolysis was completed by the release of the 1-pyrenyl methylene groups from the polymer backbone (Figure 11). By removing the organic solvents under vacuum, cleaved-hydrophobic pyrene methylene groups were precipitated in water phase and removed by filtration and followed by dialysis. Through this polarity change on the surface from hydrophobic pyrene to hydrophilic carboxylic acid units, the nanoparticles were moved completely to the aqueous phase without aggregation or addition of the second surfactant layer. Particles were stabilized successfully by the hydrophilic PEG-b-PGlu in aqueous medium (33). By this process, poly(L-lactide) nanoparticles having a fully biocompatible PEG-b-Polyglutamic acid shell were obtained. Thus, the potential cytotoxicity of the non-biocompatible emulsifiers was avoided. To confirm the biocompatibility, the particles were incubated with human mesenchymal stem cells (hMSCs). After 24 hours, the particles still indicated a 100% cell viability (Figure 12) (33).



Figure 12. Live/dead staining of hMSC cells after 24-hour incubation of PEG-bPGlu emulsified PLLA nanoparticles at various dilutions. (Reproduced with permission from reference (33). Copyright (2014) John Wiley and Sons). (see color insert)

Conclusion Following a stepwise approach corresponding to the specific needs of a versatile nanoparticle system for drug release, we developed a carrier system for cancer therapy which consists of fully biocompatible polymers. Essential for this approach was the clear identification and achieving of the requirements of a biocompatible drug carrier system by a step-by-step strategy. Consequently, polylactide-based nanocarriers were synthesized and their properties tuned by tailoring the size, the chemical composition and the functional groups in order to achieve a selective drug release at tumor tissues. Polymeric carriers were fabricated in one pot at ambient temperature, resulting in an optimal size range with a spherical shape and monomodal distribution. Further, by initiating the polymerization of lactide with a bifunctional bioactive MMP-2 peptide, triblock copolymer nanoparticles were prepared and physically loaded with dyes and drugs during the particle formation. Cell internalization studies demonstrated the uptake as confirmed by CARS and TPEF. The therapeutic efficiency was shown by the high cell-toxicity versa cancer cells which is caused by a full degradation of the drug-loaded particles by the, in such cells overexpressed, MMP-2 enzyme. Considering biocompatibility and triggered drug release at specific target regions a highly promising platform for future nanocarriers is achieved.


References 1. 2.

3.


4.

5.

6. 7.

8.

9.

10.

11.

12.

13. 14.

15.

Mohanraj, V.; Chen, Y. Nanoparticles – A Review. Trop. J. Pharm. Res. 2006 June, 5, 561–573. Sarasua, J. R.; Arraiza, A. L.; Balerdi, P.; Maiza, I. Crystallinity and Mechanical Properties of Optically Pure Polylactides and Their Blends. Polym. Eng. Sci. 2005, 45 (5), 745–753. Xiao, L.; Wang, B.; Yang, G.; Gauthier, M. Poly(Lactic Acid)-Based Biomaterials: Synthesis, Modification and Applications. In Biomedical Science, Engineering and Technology; Ghista, D. N., Ed; InTech, 2012; Chapter 11, pp 247−282. Vert, M.; Li, S. M.; Spenlehauer, G.; Guerin, P. Bioresorbability and Biocompatibility of Aliphatic Polyesters. J. Mater. Sci. Mater. Med. 1992, 3 (6), 432–446. Nicolas, J.; Mura, S.; Brambilla, D.; Mackiewicz, N.; Couvreur, P. Design, Functionalization Strategies and Biomedical Applications of Targeted Biodegradable/biocompatible Polymer-Based Nanocarriers for Drug Delivery. Chem. Soc. Rev. 2013, 42 (3), 1147–1235. Bader, H.; Ringsdorf, H.; Schmidt, B. Watersoluble Polymers in Medicine. Die Angew. Makromol. Chemie 1984, 123 (1), 457–485. Nasongkla, N.; Bey, E.; Ren, J.; Ai, H.; Khemtong, C.; Guthi, J. S.; Chin, S. F.; Sherry, A. D.; Boothman, D. A.; Gao, J. Multifunctional Polymeric Micelles as Cancer-Targeted, MRI-Ultrasensitive Drug Delivery Systems. Nano Lett. 2006, 6 (11), 2427–2430. Kataoka, K.; Harada, A.; Nagasaki, Y. Block Copolymer Micelles for Drug Delivery: Design, Characterization and Biological Significance. Adv. Drug Deliv. Rev. 2001, 47 (1), 113–131. Klapper, M.; Nenov, S.; Haschick, R.; Müller, K.; Müllen, K. Oil-in-Oil Emulsions: A Unique Tool for the Formation of Polymer Nanoparticles. Acc. Chem. Res. 2008, 41 (9), 1190–1201. Dorresteijn, R.; Haschick, R.; Klapper, M.; Müllen, K. Poly(L -Lactide) Nanoparticles via Ring-Opening Polymerization in Non-Aqueous Emulsion. Macromol. Chem. Phys. 2012, 213 (19), 1996–2002. Bawarski, W. E.; Chidlowsky, E.; Bharali, D. J.; Mousa, S. A. Emerging Nanopharmaceuticals. Nanomedicine Nanotechnology, Biol. Med. 2008, 4 (4), 273–282. Emerich, D. F.; Thanos, C. G. The Pinpoint Promise of Nanoparticle-Based Drug Delivery and Molecular Diagnosis. Biomol. Eng. 2006, 23 (4), 171–184. Cho, K.; Wang, X.; Nie, S.; Chen, Z.; Shin, D. M. Therapeutic Nanoparticles for Drug Delivery in Cancer. Clin. Cancer Res. 2008, 14 (5), 1310–1316. Nagy, J. A.; Chang, S.-H.; Dvorak, A. M.; Dvorak, H. F. Why Are Tumour Blood Vessels Abnormal and Why Is It Important to Know? Br. J. Cancer 2009, 100 (6), 865–869. Heldin, C.-H.; Rubin, K.; Pietras, K.; Ostman, A. High Interstitial Fluid Pressure - An Obstacle in Cancer Therapy. Nat. Rev. Cancer 2004, 4 (10), 806–813. 244

Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


16. Matsumura, Y.; Maeda, H. A New Concept for Macromolecular Therapeutics in Cancer Chemotherapy: Mechanism of Tumoritropic Accumulation of Proteins and the Antitumor Agent Smancs. Cancer Res. 1986, 46 (8), 6387–6392. 17. Haag, R. Supramolecular Drug-Delivery Systems Based on Polymeric CoreShell Architectures. Angew. Chemie Int. Ed. 2004, 43 (3), 278–282. 18. Yuan, F.; Dellian, M.; Fukumura, D.; Leunig, M.; Berk, D. A.; Jain, R. K.; Torchilin, V. P. Vascular Permeability in a Human Tumor Xenograft: Molecular Size Dependence and Cutoff Size. Cancer Res. 1995, 55 (17), 3752–3756. 19. Papa, V.; Gliozzo, B.; Clark, G. M.; McGuire, W. L.; Moore, D.; FujitaYamaguchi, Y.; Vigneri, R.; Goldfine, I. D.; Pezzino, V. Insulin-like Growth Factor-I Receptors Are Overexpressed and Predict a Low Risk in Human Breast Cancer. Cancer Res. 1993, 53 (16), 3736–3740. 20. McCawley, L. J.; Matrisian, L. M. Matrix Metalloproteinases: Multifunctional Contributors to Tumor Progression. Mol. Med. Today 2000, 6 (4), 149–156. 21. Olson, E. S.; Jiang, T.; Aguilera, T. A.; Nguyen, Q. T.; Ellies, L. G.; Scadeng, M.; Tsien, R. Y. Activatable Cell Penetrating Peptides Linked to Nanoparticles as Dual Probes for in Vivo Fluorescence and MR Imaging of Proteases. Proc. Natl. Acad. Sci. U. S. A. 2010, 107 (9), 4311–4316. 22. Jiang, T.; Olson, E. S.; Nguyen, Q. T.; Roy, M.; Jennings, P. A.; Tsien, R. Y. Tumor Imaging by Means of Proteolytic Activation of Cell-Penetrating Peptides. Proc. Natl. Acad. Sci. U. S. A. 2004, 101 (51), 17867–17872. 23. Egeblad, M.; Werb, Z. New Functions for the Matrix Metalloproteinases in Cancer Progression. Nat. Rev. Cancer 2002, 2 (1474–175X), 161–174. 24. Brinckerhoff, C. E.; Matrisian, L. M. Matrix Metalloproteinases: A Tail of a Frog That Became a Prince. Nat. Rev. Mol. Cell Biol. 2002, 3 (3), 207–214. 25. Harris, T. J.; Von Maltzahn, G.; Lord, M. E.; Park, J. H.; Agrawal, A.; Min, D. H.; Sailor, M. J.; Bhatia, S. N. Protease-Triggered Unveiling of Bioactive Nanoparticles. Small 2008, 4 (9), 1307–1312. 26. Olson, E. S.; Aguilera, T. a; Jiang, T.; Ellies, L. G.; Nguyen, Q. T.; Wong, E. H.; Gross, L. a; Tsien, R. Y. In Vivo Characterization of Activatable Cell Penetrating Peptides for Targeting Protease Activity in Cancer. Integr. Biol. (Camb). 2009, 1 (5–6), 382–393. 27. Zhang, Y.; So, M. K.; Rao, J. Protease-Modulated Cellular Uptake of Quantum Dots. Nano Lett. 2006, 6 (9), 1988–1992. 28. Andrieu, J.; Kotman, N.; Maier, M.; Mailänder, V.; Strauss, W. S. L.; Weiss, C. K.; Landfester, K. Live Monitoring of Cargo Release from Peptide-Based Hybrid Nanocapsules Induced by Enzyme Cleavage. Macromol. Rapid Commun. 2012, 33 (3), 248–253. 29. Huehn, D.; Kantner, K.; Geidel, C.; Brandholt, S.; De Cock, I.; Soenen, S. J. H.; Riveragil, P.; Montenegro, J. M.; Braeckmans, K.; Müllen, K.; Nienhaus, G. U.; Klapper, M.; Parak, W. J. Polymer-Coated Nanoparticles Interacting with Proteins and Cells: Focusing on the Sign of the Net Charge. ACS Nano 2013, 7 (4), 3253–3263. 245 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


30. Jiang, J.; Tong, X.; Zhao, Y. A New Design for Light-Breakable Polymer Micelles. J. Am. Chem. Soc. 2005, 127 (23), 8290–8291. 31. Dorresteijn, R.; Ragg, R.; Rago, G.; Billecke, N.; Bonn, M.; Parekh, S. H.; Battagliarin, G.; Peneva, K.; Wagner, M.; Klapper, M.; Müllen, K. Biocompatible Polylactide-Block-Polypeptide-Block-Polylactide Nanocarrier. Biomacromolecules 2013, 14 (5), 1572–1577. 32. Dorresteijn, R.; Billecke, N.; Schwendy, M.; Pütz, S.; Bonn, M.; Parekh, S. H.; Klapper, M.; Müllen, K. Polylactide-Block-Polypeptide-BlockPolylactide Copolymer Nanoparticles with Tunable Cleavage and Controlled Drug Release. Adv. Funct. Mater. 2014, 24 (26), 4026–4033. 33. Dorresteijn, R.; Billecke, N.; Parekh, S. H.; Klapper, M.; Müllen, K. Polarity Reversal of Nanoparticle Surfaces by the Use of Light-Sensitive Polymeric Emulsifiers. J. Polym. Sci., Part A: Polym. Chem. 2015, 53 (2), 200–205. 34. Sodergard, A. Chemical and Morphological Changes in Peroxide-Stabilized Poly (L-Lactide). Hydrogels Biodegrad. Polym. Bioapplications 1996, 627 (1), 103–117. 35. Filachione, E. M.; Fisher, C. H. Lactic Acid Condensation Polymers. Ind. Eng. Chem. 1944, 36 (3), 223–228. 36. Connor, E. F.; Nyce, G. W.; Myers, M.; Möck, A.; Hedrick, J. L. First Example of N-Heterocyclic Carbenes as Catalysts for Living Polymerization: Organocatalytic Ring-Opening Polymerization of Cyclic Esters. J. Am. Chem. Soc. 2002, 124 (6), 914–915. 37. Ueda, M.; Kreuter, J. Optimization of the Preparation of Loperamide-Loaded Poly (L-Lactide) Nanoparticles by High Pressure Emulsification-Solvent Evaporation. J. Microencapsul. 1997, 14 (5), 593–605. 38. Vandervoort, J.; Ludwig, A. Biocompatible Stabilizers in the Preparation of PLGA Nanoparticles: A Factorial Design Study. Int. J. Pharm. 2002, 238 (1–2), 77–92. 39. Legrand, P.; Lesieur, S.; Bochot, A.; Gref, R.; Raatjes, W.; Barratt, G.; Vauthier, C. Influence of Polymer Behaviour in Organic Solution on the Production of Polylactide Nanoparticles by Nanoprecipitation. Int. J. Pharm. 2007, 344 (1–2), 33–43. 40. Haschick, R.; Klapper, M.; Wagener, K. B.; Müllen, K. Nanoparticles by ROMP in Nonaqueous Emulsions. Macromol. Chem. Phys. 2010, 211 (24), 2547–2554. 41. Haschick, R.; Mueller, K.; Klapper, M.; Muellen, K. Nonaqueous Emulsions as a Tool for Particles with Unique Core-Shell Topologies. Macromolecules 2008, 41 (14), 5077–5081. 42. Müller, G. R. J.; Meiners, C.; Enkelmann, V.; Geerts, Y.; Müllen, K. Liquid Crystalline Perylene-3,4-Dicarboximide Derivatives with High Thermal and Photochemical Stability. J. Mater. Chem. 1998, 8 (1), 61–64. 43. Sun, T.; Zhang, Y. S.; Pang, B.; Hyun, D. C.; Yang, M.; Xia, Y. Engineered Nanoparticles for Drug Delivery in Cancer Therapy. Angew. Chem., Int. Ed. 2014, 53 (46), 12320–12364. 44. Zhu, L.; Kate, P.; Torchilin, V. P. Matrix Metalloprotease 2-Responsive Multifunctional Liposomal Nanocarrier for Enhanced Tumor Targeting. ACS Nano 2012, 6 (4), 3491–3498. 246 Ilies; Control of Amphiphile Self-Assembling at the Molecular Level: Supra-Molecular Assemblies with Tuned ... ACS Symposium Series; American Chemical Society: Washington, DC, 2017.


45. Matsumura, S.; Aoki, I.; Saga, T.; Shiba, K. A Tumor-EnvironmentResponsive Nanocarrier That Evolves Its Surface Properties upon Sensing Matrix Metalloproteinase-2 and Initiates Agglomeration to Enhance T2 Relaxivity for Magnetic Resonance Imaging. Mol. Pharm. 2011, 8 (11), 1970–1974. 46. Fried, J.; Perez, A. G.; Doblin, J. M.; Clarkson, B. D. Cytotoxic and Cytokinetic Effects of Thymidine, 5-Fluorouracil, and Deoxycytidine on Hela Cells in Culture. Cancer Res. 1981, 41 (7), 2627–2632. 47. Yamamoto, S.; Tanaka, H.; Kanamori, T.; Nobuhara, M.; Namba, M. In Vitro Studies on Potentiation of Cytotoxic Effects of Anticancer Drugs by Interferon on a Human Neoplastic Cell Line (HeLa). Cancer Lett. 1983, 20 (2), 131–138. 48. Kherif, S.; Lafuma, C.; Dehaupas, M.; Lachkar, S.; Fournier, J. G.; Verdière-Sahuqué, M.; Fardeau, M.; Alameddine, H. S. Expression of Matrix Metalloproteinases 2 and 9 in Regenerating Skeletal Muscle: A Study in Experimentally Injured and Mdx Muscles. Dev. Biol. 1999, 205, 158–170.


Biocompatible Nanoparticles for Selective Drug Release at Cancer Cells

Recommend Documents