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Current clinical outcomes using chimeric-antigen receptors (CARs) against multiple myeloma show promise in the eradication of bulk disease. However, these anti-BCMA (CD269) CARs observe relapse as a common phenomenon after treatment due to the reemergence of either antigen-positive or -negative cells. Hence, the development of improvements in CAR design to target antigen loss and increase effector cell persistency represents a critical need. Here, we report on the anti-tumor activity of a CAR T-cell possessing two complete and independent CAR receptors against the multiple myeloma antigens BCMA and CS1. We determined that the resulting compound CAR (cCAR) T-cell possesses consistent, potent and directed cytotoxicity against each target antigen population. Using multiple mouse models of myeloma and mixed cell populations, we are further able to show superior in vivo survival by directed cytotoxicity against multiple populations compared to a single-expressing CAR T-cell. These findings indicate that compound targeting of BCMA and CS1 on myeloma cells can potentially be an effective strategy for augmenting the response against myeloma bulk disease and for initiation of broader coverage CAR therapy.

The aim of the present study was to quantitatively diagnose and monitor the therapy response of hepatic ischemia–reperfusion injury (IRI) with the use of targeted ultrasound (US) imaging. Targeted microbubbles (MBs) were fabricated, and the binding of intracellular adhesion molecule 1 (ICAM‐1) antibodies to MBs was observed. To establish a quantitative method based on targeted USimaging, contrast‐enhanced USwas applied for IRIrats. After andrographolide treatment, the IRIrats were subjected to the quantitative targeted USimaging for a therapeutic effect. Effective binding of ICAM‐1 antibodies to MBs was observed. According to the quantitative targeted USimaging, the ICAM‐1 normalized intensity difference (NID) in the IRIrats (38.74 ± 15.08%) was significantly higher than that in the control rats (10.08 ± 2.52%, p=0.048). Further, different degrees of IRI(mild IRI, moderate to severe IRI) were distinguished by the use of the NID(37.14 ± 2.14%, 22.34 ± 1.08%, p=0.002). Analysis of mRNAexpression demonstrated the accuracy of analyzing the NIDby using quantitative targeted USimaging (R2 = 0.7434, p< 0.001). Andrographolide treatment resulted in an obviously weakened NIDof ICAM‐1 (17.7 ± 4.8% vs 34.2 ± 6.6%, p< 0.001). The study showed the potential of the quantitative targeted USimaging method for the diagnosis and therapeutic monitoring of IRI. A quantitative ultrasound imaging method based on intracellular adhesion molecule 1 targeting can diagnose different degrees of hepatic ischemia–reperfusion injury and monitor anti‐inflammatory effects after andrographolide treatment.

The aim of the present study was to quantitatively diagnose and monitor the therapy response of hepatic ischemia–reperfusion injury (IRI) with the use of targeted ultrasound (US) imaging. Targeted microbubbles (MBs) were fabricated, and the binding of intracellular adhesion molecule 1 (ICAM-1) antibodies to MBs was observed. To establish a quantitative method based on targeted US imaging, contrast-enhanced US was applied for IRI rats. After andrographolide treatment, the IRI rats were subjected to the quantitative targeted US imaging for a therapeutic effect. Effective binding of ICAM-1 antibodies to MBs was observed. According to the quantitative targeted US imaging, the ICAM-1 normalized intensity difference (NID) in the IRI rats (38.74 ± 15.08%) was significantly higher than that in the control rats (10.08 ± 2.52%, p = 0.048). Further, different degrees of IRI (mild IRI, moderate to severe IRI) were distinguished by the use of the NID (37.14 ± 2.14%, 22.34 ± 1.08%, p = 0.002). Analysis of mRNA expression demonstrated the accuracy of analyzing the NID by using quantitative targeted US imaging (R2= 0.7434, p <0.001). Andrographolide treatment resulted in an obviously weakened NID of ICAM-1 (17.7 ± 4.8% vs 34.2 ± 6.6%, p <0.001). The study showed the potential of the quantitative targeted US imaging method for the diagnosis and therapeutic monitoring of IRI.

The outlook for T-cell malignancies remain poor due to the lack of effective therapeutic options. Chimeric antigen receptor (CAR) immunotherapy has recently shown promise in clinical trials for B-cell malignancies, however, designing CARs for T-cell based disease remain a challenge due to the shared surface antigen pool between normal and malignant T-cells. Normal T-cells express CD5 but NK (natural killer) cells do not, positioning NK cells as attractive cytotoxicity cells for CD5CAR design. Additionally, CD5 is highly expressed in T-cell acute lymphoblastic leukemia (T-ALL) and peripheral T-cell lymphomas (PTCLs). Here, we report a robust anti-CD5 CAR (CD5CAR) transduced into a human NK cell line NK-92 that can undergo stable expansion ex vivo. We found that CD5CAR NK-92 cells possessed consistent, specific, and potent anti-tumor activity against a variety of T-cell leukemia and lymphoma cell lines as well as primary tumor cells. Furthermore, we were able to demonstrate significant inhibition and control of disease progression in xenograft mouse models of T-ALL. The data suggest that CAR redirected targeting for T-cell malignancies using NK cells may be a viable method for new and complementary therapeutic approaches that could improve the current outcome for patients.

Artesunate (ART) has been known as the most effective and safe reagents to treat malaria for many years. In this study, we explored whether ART could protect pancreatic beta-cell against cytokine-induced damage. The production of nitrite (NO) was detected with the Griess Assay Kit. SIRT1 and inducible nitric oxide synthase (iNOS) expression were determined with Western blot. The transcriptional activity of NF-κB was evaluated by luciferase reporter assay. The expression of Sirt1 was silenced by RNA interference. Glucose-stimulated insulin secretion (GSIS) and potassium-stimulated insulin secretion (KSIS) assays were performed to measure the effect of ART on pancreatic beta-cells’ function. The effect of ART on beta-cells apoptosis was evaluated by using Hochest/PI staining and TUNEL assay. ART enhanced GSIS (KSIS) and reduced apoptosis of pancreatic beta-cells induced by IL-1β. Further study showed that ART inhibited IL-1β-induced increase of NF-κB activity, iNOS expression, and NO production. Moreover, ART up-regulated SIRT1 expression in INS-1 cells and islets exposed to IL-1β. Inhibition of SIRT1 expression could partially abolished the inhibitory effect of ART on NF-κB activity in IL-1β-treated beta-cells. More importantly, the protective effect of ART on cytokine-induced damage was reversed by silencing SIRT1 expression. ART can elicit a protective effect on beta-cells exposed to IL-1β by stimulating SIRT1 expression, which resulted in the decrease of NF-κB activity, iNOS expression, and NO production. Hence, ART might be an effective drug for diabetes.

We report a simple chemical conversion approach to fabricate ZnO/ZnS core/shell nanorods and various metal sulfide nanotubes such as ZnS, Ag2S, CuS, PbS, and Bi2S3. The formation mechanisms of the ZnO/ZnS core/shell nanorods and ZnS nanotubes are due to the sulfidation conversion and the Kirkendall effect, respectively, in a low-temperature hydrothermal growth through the reaction of ZnO nanowires and thioacetamide. The successful chemical conversion of the ZnS nanotubes into the other metal sulfide nanotubes is to utilize the large difference in solubility between ZnS and the other metal sulfides for the effective transformation. In addition to the perfect maintenance of the morphology after conversion, we have shown that the yielded metal sulfide nanostructures possess good crystalline qualities with high optical and sensing performances. The present chemical conversion technique is expected to be employed in a broad range of applications to fabricate innovative semiconductor core/shell and hollow structures with various compositions and shapes for unique properties.

Soluble supramolecular inclusion complexes were formed by threading α-cyclodextrin (α-CD) molecules over poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) chains of ternary block copolymers of PEG, PCL and polyethylenimine (PEI). Characteristic shifts of PCL absorptions in FTIR, ¹H NMR and UV spectra strongly suggest that α-CD is threaded over PEG and PCL blocks. Due to the reduced hydrophobic interaction between PCL blocks, the resulting supramolecular complexes displayed a dramatically increased solubility, in comparison with the ternary block copolymers. Their ability to complex DNA was almost as efficient as that of branched PEI 25 kDa, as shown in the ethidium bromide fluorescence quenching experiments. Resulting DNA polyplexes displayed a size of around 200 nm and a neutral surface charge. Microscopy studies in 3T3 fibroblasts revealed an efficient cellular uptake. Transfection efficiencies of inclusion complexes were in the same order of magnitude as PEI. In contrast to PEI a 100× lower toxicity was observed by MTT-assay, allowing the administration of nitrogen-to-phosphate ratios of up to 20. These new gene delivery systems merit further characterization under in vivo conditions.

We describe the successful mixing of polymer pairs and triplets that are normally incompatible to form blends that possess molecular‐level homogeneity. This is achieved by the simultaneous formation of crystalline inclusion compounds (ICs) between host cyclodextrins (CDs) and two or more guest polymers, followed by coalescing the included guest polymers from their common CD–ICs to form blends. Several such CD–IC fabricated blends, including both polymer1/polymer2 binary and polymer1/ polymer2/polymer3 ternary blends, are described and examined by means of X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and solid‐state NMR to probe their levels of mixing. It is generally observed that homogeneous blends with a molecular‐level mixing of blend components is achieved, even when the blend components are normally immiscible by the usual solution and melt blending techniques. In addition, when block copolymers composed of inherently immiscible blocks are coalesced from their CD–ICs, significant suppression of their normal phase‐segregated morphologies generally occurs. Preliminary observations of the thermal and temporal stabilities of the CD–IC coalesced blends and block copolymers are reported, and CD–IC fabrication of polymer blends and reorganization of block copolymers are suggested as a potentially novel means to achieve a significant expansion of the range of useful polymer materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4207–4224, 2004

Well-defined dendrimer-like star block copolymers up to 24 arm were successfully achieved by combination of living ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) on the basis of poly(aryl ether) dendrimers (CMGn-OH, n = 1−3, with functionality of 6, 12, and 24, respectively). Star polylactides (CMGn-PLLA) were synthesized by bulk polymerization of l-lactide with multifunctional dendrimer initiators and stannous octoate catalyst. The molecular weights of CMGn-PLLA increased linearly with increasing monomer conversion, with molecular weight distributions remaining below 1.15, indicating the living nature of polymerization. CMGn-PLLA was converted into a macroinitiator CMGn-PLLABr via esterification with 2-bromoisobutyryl bromide. ATRP of methyl methacrylate (MMA) and styrene (St) using the CMGn-PLLABr/CuBr/pentamethyldiethylenetriamine initiating system afforded star block copolymers with predetermined molecular weights and narrow molecular weight distributions (1.05 &lt; Mw/Mn &lt; 1.20). The molecular weights of star polymers and star block copolymers could be adjusted by the variation of monomer-to-initiator ratios and monomer conversion. The precise arm numbers of 6, 12, and 24 for the resultant star polylactides and star block copolymers were confirmed by NMR spectra analysis and the hydrolysis approach, respectively.

Cross-linkable di- and triblock copolymers of poly(ε-caprolactone) (PCL) and monomethoxyl poly(ethylene glycol) (MPEG) were synthesized. These amphiphilic copolymers self-assembled into nanoscale micelles capable of encapsulating hydrophobic paclitaxel in their hydrophobic cores in aqueous solutions. To further enhance their thermodynamic stability, the micelles were cross-linked by radical polymerization of the double bonds introduced into the PCL blocks. Reaction conditions were found to significantly affect both the cross-linking efficiency and the micelle size. The encapsulation of paclitaxel into the micelles was confirmed by the proton nuclear magnetic resonance (¹H NMR) spectroscopy. Encouragingly, paclitaxel-loading efficiency of micelles was enhanced significantly upon micelle core-cross-linking. Both the micelle size and the drug loading efficiency increased markedly with increasing the PCL block lengths, no matter if the micelles were core-cross-linked or not. However, paclitaxel-loading did not obviously affect the micelle size or size distribution. The cross-linked micelles exhibited a significantly enhanced thermodynamic stability against dilution with aqueous solvents. The efficient cellular uptake of paclitaxel loaded in the nanomicelles was demonstrated by confocal laser scanning microscopy (CLSM) imaging. This new biodegradable nanoscale carrier system merits further investigations for parenteral drug delivery.

Diblock copolymers (MPEG-b-PCLs) of poly(ε-caprolactone) (PCL) and monomethoxyl poly(ethylene glycol) (MPEG) were synthesized by the conventional ring-opening polymerization of ε-caprolactone using MPEG as a macroinitiator. The monohydroxy-bearing diblock copolymers were reacted first with maleic anhydride and then with N-hydroxysuccinimide (NHS) to yield activated succinimidyl carbonate derivatives that are reactive with the primary amino group. Subsequently, a new class of biodegradable amphiphilic copolymer (hy-PEI-g-PCL-b-PEG) was prepared by grafting the activated PCL-b-PEG onto the hyperbranched poly(ethylene imine) (hy-PEI). Thermal properties of bulk graft copolymers were investigated using differential scanning calorimetry and thermogravimetric analysis. Depending on their compositions, these polymers are completely soluble in water or form micelles of tens to hundreds of nanometers in size in the studied concentration range, as revealed by surface tension and dynamic light scattering measurements of copolymer solutions. Complexation of plasmid DNA (pDNA) with various copolymers was investigated to achieve particles of ca. 200 nm diameter (N/P = 7). Copolymer composition was found to affect significantly the gene transfection efficiency of polyplexes. In general, low graft density and high molecular weight of PEI blocks favor high gene transfection efficiency. All DNA/copolymer complexes (N/P = 7) showed a much lower ξ-potential (i.e., neutral or negative) than the DNA/PEI25 kDa complex (21 mV), indicating lower toxicity of copolymer-based complexes. Lower cytotoxicity of DNA/copolymer complexes was also demonstrated by the viability of cells in the transfection experiments. These results indicate that these ternary copolymers are promising candidates for gene delivery, featuring good biocompatibility, potential biodegradability, and relatively high gene transfection efficiency. Their neutral surface charge offers potential for intravenous administration.

Novel biodegradable star-shaped polymers that consist of poly(l-lactide) (PLLA) arms and a starburst PAMAM dendrimer core were prepared by ring-opening polymerization of l-lactide with PAMAM-OH dendrimer (generation 1−4) initiators and a stannous octoate catalyst in bulk at 130 °C. The molecular weights of the star-shaped polymers were measured by GPC, ¹H NMR, and SLS. It was found that the molecular weight of the synthesized star-shaped polylactides can be controlled by variation of the generation of the dendrimer initiators and the molar ratio of monomer to initiator. Effects of molecular weight and number of arms on the thermal properties and hydrolytic degradation of the star-shaped polylactides were investigated. For polylactides initiated with the same dendrimer initiator, the melting temperature and crystallinity increased with increasing molecular weight. For star-shaped polylactides initiated with dendrimer initiators with different generations, the melting point, crystallinity, crystallization rate, and maximum decomposition temperature decreased as the number of arms increased, while the corresponding hydrolysis rate increased.

Inclusion complexed (IC) and coalesced biodegradable poly(ε-caprolactone) (PCL), poly(L-lactic acid) (PLLA), and their diblock copolymer (PCL-b-PLLA) were achieved by forming ICs between host α-cyclodextrin(α-CD) and guest PCL, PLLA, and PCL-b-PLLA, followed by removing the α-CD host with an amylase enzyme. FTIR spectra of the coalesced polymers reveal that the host α-CD can be completely removed, without polymer degradation, by treatment with an amylase enzyme. The melting and crystallization behavior of these CD-IC treated polymers, which are crystallizable, biodegradable, and bioabsorbable, are investigated by differential scanning calorimetry (DSC) and polarized optical microscopy. Results show that coalescence increased the crystallinities of the homopolymers but decreased that of the diblock copolymer. The Avrami exponent (n), derived from both isothermal and nonisothermal crystallization models for homo-PCL and -PLLA and the PCL and PLLA blocks in the diblock copolymer samples coalesced from their ICs, is close to 4, indicating homogeneous crystallization, whereas crystallization of the blocks in the as-synthesized diblock copolymer yields an Avrami exponent around 3, indicating heterogeneous crystallization. All of these results demonstrate that the PCL and PLLA homopolymers and blocks in the IC-coalesced samples are more readily and homogeneously crystallized than those in the as-synthesized samples or their physical blend, even though the level of crystallinity in the IC-coalesced diblock copolymer is significantly lower. Moreover, unlike the as-synthesized diblock copolymer, the crystallization of PCL and PLLA blocks in the IC-coalesced diblock copolymer are not influenced by their covalent connection.

The experimental procedures to place poly(ethylene 2,6-naphthalate) (PEN) guest molecules within γ-cyclodextrin (γ-CD) host molecules are described along with the subsequent verification of inclusion-compound (IC) formation. In addition, the simultaneous complexing of PEN and poly(ethylene terephthalate) (PET) with γ-CD to form their common IC is documented. Coalescence from their common γ-CD IC generates an intimate blend of the PET and PEN polymers contained therein. Thermal analysis via differential scanning calorimetry reveals thermal behavior indicative of an intimate blend of PET and PEN. ¹H NMR analysis confirms that the intimate blending of PET and PEN achieved by coalescence from their common γ-CD IC is not due to transesterification into a PET/PEN copolymer during thermal analysis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 139–148, 2003

The miscibility and phase behavior of two stereoisomer forms of poly(lactide) (PLA: poly (l-lactide) (PLLA) and poly(dl-lactide) (PDLLA)) blends with poly(ε-caprolactone)-b-poly(ethylene glycol) (PCL-b-PEG) and PCL-b-monomethoxy-PEG (PCL-b-MPEG) block copolymers have been investigated by differential scanning calorimetry (DSC). The DSC thermal behavior of both the blend systems revealed that PLA is miscible with the PEG segment phase of PCL-b-(M)PEG but is still immiscible with its PCL segment phase although PCL was block-copolymerized with PEG. On the basis of these results, PCL-b-PEG was added as a compatibilizer to PLA/PCL binary blends. The improvement in mechanical properties of PLA/PCL blends was achieved as anticipated upon the addition of PCL-b-PEG. In addition, atomic force microscopy (AFM) measurements have been performed in order to study the compositional synergism to be observed in mechanical tests. AFM observations of the morphological dependency on blend composition indicate that PLA/PCL blends are immiscible but compatible to some extent and that synergism of compatibilizing may be maximized in the compositional blend ratio before apparent phase separation and coarsening.

Atactic poly(R,S-3-hydroxybutyrate) (a-PHB) was synthesized by anionic polymerization of β-butyrolactone with potassium methoxide as an initiator. This completely amorphous polyester is capable of forming a crystalline inclusion complex (IC) with γ-cyclodextrin (γ-CD) adopting a channel structure. There is no evidence showing that a-PHB may form IC with either α-CD or β-CD. On the basis of these discoveries, a common IC was formed with two polymer chains, a-PHB and poly(ε-caprolactone) (PCL), randomly distributed into the channels of γ-CD-PCL/a-PHB IC crystals. Nevertheless, in the formation of the common IC, PCL inclusion appears superior to a-PHB inclusion. Therefore, the molar ratio of a-PHB and PCL in the coalesced sample has been detected to be lower than that used in the formation of the common IC. Washing the common IC with hot water removed the γ-CD, and the molecular chains of the two polymers were coalesced. Very interestingly, only a single glass transition temperature (Tg), dependent on the composition, was observed between the Tg's of a-PHB (~5 °C) and PCL (~−60 °C) in the differential scanning calorimetry (DSC) measurements of the coalesced samples. To the contrary, Tg of a-PHB (~5 °C) was found to remain unchanged in the physical blend with PCL. Tm's of coalesced blend samples are lower than that of pure PCL, while the Tm of the physical blend is almost the same as that of pure PCL. These results strongly demonstrate that the miscibility of the inherently immiscible a-PHB/PCL pair has been improved in the coalesced blends. Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), ¹³C solid-state NMR, DSC, and wide-angle X-ray diffraction (WAXD) measurements were employed to demonstrate IC formation.

A triblock copolymer (PCL−PPG−PCL, Mn = 1.38 × 10⁴) of poly(ε-caprolactone) (PCL) and poly(propylene glycol) (PPG) was synthesized by ring-opening polymerization of ε-caprolactone. Cyclodextrin (CD)-type-dependent formation of inclusion complexes (ICs) between cyclodextrins and this triblock copolymer was studied. Only PCL blocks were included as guests in the IC formed with α-cyclodextrin (α-CD), while both PCL and PPG blocks were included in the IC formed with γ-cyclodextrin (γ-CD). As a result, the copolymer coalesced from its IC crystals with α-CD showed an increased crystallinity, while to the contrary, the copolymer coalesced from its IC crystals with γ-CD exhibited a decreased crystallinity, when both were compared to the as-synthesized triblock copolymer. Fourier transform infrared (FTIR) spectra, ¹³C CP/MAS solid-state NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD) measurements were employed to study the formation of ICs as well as to gauge the microphase separation in the coalesced samples.

A biodegradable block copolymer (PCL-b-PLLA, Mn = 1.72 × 10⁴, Mw/Mn = 1.37) of poly(ε-caprolactone) (PCL) and poly(l-lactide) (PLLA) with very low crystallinity was obtained by forming the inclusion complex between α-cyclodextrin molecules and PCL-b-PLLA followed by coalescence of the guest polymer chains. Films of the as-synthesized and coalesced copolymer samples, PCL and PLLA homopolymers of approximately the same chain lengths as the corresponding blocks of PCL-b-PLLA, and a physical blend of PCL/PLLA homopolymers with the same molar composition as PCL-b-PLLA were prepared by melt-compression molding between Teflon plates. Subsequently, the in vitro biodegradation behavior of these films was studied in phosphate buffer solution containing lipase from Rhizopus arrhizus, by means of ultraviolet spectra, attenuated total reflectance FTIR spectra, differential scanning calorimetry, wide-angle X-ray diffraction measurements, and weight loss analysis. PCL segments were found to degrade much faster than PLLA segments, both in the pure state and in copolymer or blend samples. Consistent with our expectation, suppression of the phase separation, as well as a decrease of crystallinity, in the coalesced copolymer sample led to a much faster enzymatic degradation than that of either as-synthesized copolymer or the PCL/PLLA physical blend sample, especially during the early stages of biodegradation. Thus the biodegradation behavior of biodegradable block copolymers, which is of decisive importance in drug delivery and controlled release systems, may be regulated by the novel and convenient means recently reported by us.¹

An interesting phenomenon, the thickening and thinning of polymer films in the water media, was investigated in this paper. The studied polymer films were cast from atactic poly(R,S-3-hydroxybutyrate)/poly(4-vinylphenol) (PVPh) and syndiotactic poly(R,S-3-hydroxybutyrate)/PVPh blends solution. The physical properties of the blend films were characterized by differential scanning calorimetry (DSC), and the hydrogen-bonding network in the blends was characterized with the employment of Fourier transform infrared spectroscopy (FT-IR). The thickening and thinning process of the polymer films in water media was monitored by the measurement of the thickness. The effects of temperature and surfactants on the process were evaluated, furthermore, and the essence of the thickening and thinning of the polymer films was discussed.

A well-defined biodegradable block copolymer (PCL-b-PLLA, Mn = 1.72 × 10⁴, Mw/Mn = 1.37) of poly(ε-caprolactone) (PCL) and poly(l-lactide) (PLLA) was synthesized by a two-step ring-opening polymerization of ε-caprolactone and l-lactide. Furthermore, we found that α-cyclodextrin (α-CD) molecules may simultaneously thread onto both PLLA and PCL blocks of PCL-b-PLLA to form an inclusion complex (IC). Washing the copolymer−α-CD IC with hot water removed the α-CD, and the copolymer chains were coalesced. Very interestingly, the coalesced copolymer sample shows a great suppression in microphase separation, compared with the as-synthesized copolymer. In contrast to the significant decrease in crystallinity of ca. 50% and up to 79% for PCL and PLLA blocks, respectively, the melting points (Tm's) and the cold crystallization temperatures (Tcc's) of both PCL and PLLA blocks of the coalesced sample increased in DSC measurements. These results may imply that only small amounts of more extended crystals, with less chain folding, were produced during the process of copolymer coalescence. Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD) measurements were employed to demonstrate formation of the block copolymer−α-CD IC as well as to gauge the suppression of the microphase separation in the coalesced sample.

The phase structure and biodegradability were investigated for amorphous blends of chemosynthetic fully amorphous atactic poly(R,S-3-hydroxybutyrate) (a-PHB) with atactic poly(methyl methacrylate) (PMMA) and atactic poly(R,S-lactide) (a-PLA). The differential scanning calorimetry thermal analysis indicated that a-PHB/PMMA blends were partially miscible while a-PHB/a-PLA blends were miscible in the studied composition range. The biodegradations of the blends were carried out in phosphate buffer solution in the presence of bacterial poly(R-3-hydroxybutyrate) extracellular depolymerases purified from Alcaligenes faecalis T1 and P. stutzeri. Although a-PHB in the pure state was not degraded by these depolymerase, it was degraded by blending with PMMA and a-PLA. The results demonstrated that the enzymatic degradation of a-PHB can be induced by amorphous polymers such as PMMA and a-PLA. Also, the biodegradation rate of a-PHB in the blends decreased drastically when the degradation temperature is too much away from the polymer glass transition temperatures. On the basis of these results, a temperature window of the enzymatic degradation was first proposed for the blend and the essence of induced degradation was discussed.