The formulation of poly(lactic-co-glycolic acid) nanoparticles as drug carriers for biomedical applications

[[abstract]]A部分: 一步製備表面覆蓋聚乙二醇的聚乳酸-甘醇酸奈米粒子在生醫上的應用 利用乳化溶劑揮發法發展出創新的一步合成表面覆蓋乙二醇的聚乳酸-甘醇酸奈米粒子(PEGPE-PLGA)，而cetyltrimethylammonium bromide (CTAB) 或是poly(ethylene glycol)- distearyl phosphoethanolamine (PEGPE)被當作在製備過程中的油相乳化劑，合成出小於50 nm的PLGA奈米粒子，這是從未被報導過的。PEGPE-PLGA的產率是隨著PEGPE/PLGA的重量比增加而提高，當PEGPE/ PLGA達到3:1時，產率可達相對的大量約為85%。PEGPE-PLGA和傳統的PLGA奈米粒子做比較可以發現有較高的藥物包覆率、降低快速的藥物釋放、好的血清穩定性及快速的細胞吸收能力，所以小於50 nm的PEGPE-PLGA展示出未來在活體上的藥物投遞應用之潛力。 我們實際利用克拉霉素(Clarithromycin)來包覆PEGPE-PLGA中做相關的研究，CL是一種半合成的大環內酯類抗生素，是被用來處理各式各樣的傳染性疾病，CL有很多劑型例如:錠劑、膠囊、內服懸浮液和靜脈注射型。然而靜脈注射的主要問題是會引起發炎並產生嚴重的疼痛；所以我們實驗室利用PEGPE- PLGA包覆CL來改善靜脈注射的問題，並且研究CL包覆在PEGPE-PLGA中的物理性質、體外藥物釋放和藥物動力學相關實驗。 B部分: 利用近紅外光照射聚乳酸-甘醇酸奈米粒子包覆奈米棒: 主動控制的藥物釋放系統 利用聚乳酸-甘醇酸(PLGA)奈米粒子同時包覆奈米金棒和代表性釋放物質如: phosphatidylethanolamine-rhodamine (PE-Rh)或是bovine serum albumin (BSA)，利用近紅外光雷射(808 ± 3 nm)照射奈米粒子，造成奈米金棒的斷裂並產生熱量，同時也使得PE-Rh、BSA從奈米粒子中釋放出來。本研究對於近紅外光照射造成藥物釋放機制加以研究外，也利用水浴溫度超過PLGA的玻璃相轉移溫度做藥物釋放實驗，來探討熱對於PLGA奈米粒子藥物釋放的影響，我們也成功利用原子力顯微鏡觀察到奈米金棒的形狀和PLGA奈米粒子表面性質改變，而推論可能是因為奈米金棒的形變和放熱而造成奈米粒子包覆的藥物釋放。發展出利用非侵入式的近紅外光雷射光源照射，來控制PLGA/奈米金棒的複合奈米粒子可以主動的藥物釋放；這種的複合奈米粒子是具有應用在活體上藥物投遞治療的潛力。[[abstract]]Part A : One-step preparation of PEG-coated poly(lactic-co-glycolic acid) nanoparticle for biomedical application A novel method was developed for the one-pot synthesis of ultrafine poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs), using an emulsion solvent evaporation formulation method. Using either cetyltrimethylammonium bromide (CTAB) or poly(ethylene glycol)-distearyl phosphoethanolamine (PEGPE) as an oily emulsifier during the emulsion process, produced PLGA particle sizes of less than 50 nm, constituting a breakthrough in emulsion formulation methods. The yield of ultrafine PLGA NPs increased with PEGPE/PLGA ratio, reaching a plateau at around 85%, when the PEGPE/PLGA ratio reached 3:1. The PEGPE–PLGA NPs exhibited high drug loading content, reduced burst release, good serum stability, and enhanced cell uptake rate compared with traditional PLGA NPs. Sub-50 nm diameter PEG-coated ultrafine PLGA NPs show great potential for in vivo drug delivery systems. Clarithromycin (CL), a semisynthetic macrolide antibiotic, is indicated for the treatment of various infectious diseases. Many dosage forms of CL, such as tablets, capsules, dry suspensions and intravenous injectable CL. However, the main problem associated with its use is that the intravenous injectable dosage form causes venous irritation which results in serious pain. For this reason, it is of great importance to develop a new formation form for CL with improved intravenous administration. Therefore, CL loaded with PEGPE-PLGA for physical property and pharmacokinetics was investigated in this study. Furthermore, PEGPE-PLGA is evaluated in many pharmaceutical applications such as drug and protein delivery systems in the future. Part B : Surface Deformation of Gold Nanorods-Loaded poly(lactic-co-glycolic acid) Nanoparticles After Near Infrared Irradiation: An Active and Controllable Drug Release System Gold nanorods (GNRs) with either phosphatidylethanolamine-rhodamine (PE-Rh) or bovine serum albumin (BSA) were co-loaded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles. PE-Rh or BSA was released from PLGA nanoparticles (NPs) after near infrared (NIR) laser irradiation (808 ± 3 nm) which made GNRs fragment and produce heat. This NIR-triggered release mechanism was investigated. Heating the PLGA NPs above PLGA’s glass temperature could not induce similar release behavior, whereas deformation and property change on PLGA NPs surface was observed by atomic force microscope. The PLGA matrix might loosened, which was caused by the mechanical agitation of the GNRs fragmentation, resulting in an active controllable release of the entrapped molecules in PLGA NPs upon NIR irradiation. The NIR thus acts as a non-invasive external light source for active and controllable drug release from the PLGA/GNR composite NPs. This type of drug delivery system may be of value in in vivo target delivery in the future.[[note]]博

Allogeneic Bone-Marrow Mesenchymal Stem Cell with Moldable Cryogel for Craniofacial Bone Regeneration

Allogeneic bone-marrow mesenchymal stem cells (BMSCs) can promote bone regeneration and substitute for autologous BMSCs if autologous sources are unavailable, but the efficacy of bone regeneration by allogeneic BMSCs is still inconsistent. A Lewis rat cranium defect model was used to investigate the efficacy of bone regeneration between autologous and allogeneic BMSCs in gelatin-nanohydroxyapatite cryogel scaffolds. BMSCs from Wistar rats served as the allogeneic cell lineage. The full-thickness cranium defects were treated by either blank control, cryogel only, allogeneic BMSC-seeded cryogel, or autologous BMSC-seeded cryogel (n = 5). Bone regeneration was monitored by micro-computed tomography and examined histologically at week 12. In addition, we assessed the immune responses in vitro by mixed lymphocyte reaction (MLR) assay and CD4+ immunochemistry staining ex vivo. The MLR showed that allogeneic BSMCs elicited a weak immune response on day 14 that progressively attenuated by day 28. In vivo, the bone regeneration in allogeneic BMSCs was inferior at week 4, but progressively matched the autologous BMSCs by week 12. Our results suggest that allogeneic BMSCs can serve as an alternative source for bone regeneration

LINC00312/YBX1 Axis Regulates Myofibroblast Activities in Oral Submucous Fibrosis

Oral submucous fibrosis (OSF) has been recognized as a precancerous disorder in the oral cavity. Great effort has been made to inhibit the malignant progression of OSF over the past decades, but the cure of this fibrosis disease has not been discovered. In the present study, we found that a long noncoding RNA, LINC00312, was upregulated in OSF tissues, and positively associated with several fibrosis factors, such as α-SMA, type I collagen, and fibronectin. As such, we sought to investigate the role of LINC00312 in OSF progression and identify its interacting factor that mediated oral fibrogenesis. Our results showed that the inhibition of LINC00312 downregulated the myofibroblast activities, including collagen gel contractility, transwell migration, and wound healing, as well as the gene expression of myofibroblast markers. We verified that YBX1 was a downstream factor of LINC00312 and revealed that the downregulation of YBX1 repressed the gene expression of α-SMA and p-Smad2 along with the reduced myofibroblast phenotypes. Most importantly, we demonstrated that the LINC00312-induced myofibroblast activities were reverted by the knockdown of YBX1, suggesting that the LINC00312-mediated myofibroblast transdifferentiation was through YBX1. Collectively, our findings revealed that the LINC00312/ YBX1 axis may serve as a target for the development of therapies against OSF

Role of Steric Effects in Protein-Directed Enediyne Cycloaromatization of Neocarzinostatin

The antibiotic neocarzinostatin comprises a carrier protein with a well-defined cavity for accommodating an active enediyne chromophore. The protein has two disulfides, one (Cys(37)-Cys(47)) lies on the cavity bottom and the other (Cys(88)-Cys(93)) in a constrained short loop. When the chromophore is not bound to the protein, a thiol-induced cycloaromatization of the enediyne into a tetrahydroindacene derivative is responsible for the potent antitumor activity. When it is protein-bound, the protein diverts the cycloaromatization pathway to form a distinct hydroxyisochromene-type product. How the protein directs the enediyne chemistry is an interesting puzzle, and various suggestions have been proposed in the past. We screened more than fifty thiols and manipulated conditions to locate reaction features and search for factors that could influence the protein directing strength. Thiol- and oxygen-concentration-dependence studies suggested that disulfides, which maintain the steric rigidity of the protein, could play a key role in diverting the cycloaromatization pathway. For direct proofs, we made mutations at each of the two disulfides by replacing sulfur atoms with oxygen. Circular dichroism and two-dimensional NMR spectroscopy studies suggested that the mutations changed neither the protein conformation nor the ligand interactions. Analyses of the thiol-induced cycloaromatization revealed that rupture of Cys(37)-Cys(47) made the protein almost completely lose its chemical directing ability, whereas rupture of Cys(88)-Cys(93) had only a minor influence. The results demonstrated that the steric rigidity of the binding cavity, but not necessary the whole protein, played an important role in the protein-directed mechanism

Superiority of N2O plasma annealing over O2 plasma annealing for amorphous tantalum pentoxide (Ta2O5) films

Japanese Journal of Applied Physics, Part 2: Letters374 BL435-L437JAPL

Polymer-Stabilized Micelles Reduce the Drug Rapid Clearance In Vivo

Micelles are self-assembled nanoscaled aggregates from amphiphilic unimers and can be used to encapsulate hydrophobic drugs. However, the dynamic exchanging of unimers between micelles and bulk solution often leads to micelle destabilization and subsequent leaking of the encapsulated substances. Thus, we incorporated a hydrophobic polymer into the micellar core for interlacing the unimers and stabilizing the micelle structure. The polymer-stabilized and non-polymer-stabilized micelles have similar physicochemical properties including small sizes (~35 nm), negative surface charges (~−35 mV), and high drug contents (~15%). Drugs encapsulated in polymer-stabilized micelles are released in a slower rate than are non-polymer-stabilized micelles. From in vivo pharmacokinetic studies, drugs loaded in polymer-stabilized micelles have lower clearance and higher plasma concentration and lower volume distribution than non-polymer-stabilized micelles have. In conclusion, polymer-stabilized micelles can reduce rapid drug clearance via strengthening of the micellar structure and increase in the available drug amount in plasma, thus broadening pharmaceutical applications of micelles

LncRNA GAS5-AS1 inhibits myofibroblasts activities in oral submucous fibrosis

Background/Purpose: Emerging research findings suggest that long non-coding RNAs (lncRNAs) are key regulators to fibrosis formation. Nevertheless, the role of lncRNA GAS5-AS1 in the progression of precancerous oral submucous fibrosis (OSF) remains to be elucidated. Methods: Quantitative real-time PCR were used to examine the expression of GAS5-AS1 in OSF tissues. The activities of myofibroblasts, including collagen contractility and cell migration, as well as the marker α-smooth muscle actin (SMA) were assessed following overexpression of GAS5-AS1. Also, we analyzed the expression of Smad activity in order to gain insight into the downstream regulator. Results: The level of GAS5-AS1 was found significantly downregulated in the OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs). Ectopic expression of GAS5-AS1 significantly reduced the abilities of collagen gel contraction and migration in fBMFs or arecoline-treated BMFs. Moreover, we have shown that overexpression of GAS5-AS1 inhibited the expression of p-Smad and the marker of myofibroblasts. Conclusion: We showed the reduced expression of GAS5-AS1 in OSF tissues and demonstrated its effect on the myofibroblast activities and the level of p-Smad and α-SMA, indicating its potential contribution in OSF pathogenesis. Keywords: lncRNA GAS5-AS1, Myofibroblasts, Oral submucous fibrosi

The Imaging Features and Clinical Associations of a Novel Tau PET Tracer—18F-APN1607 in Alzheimer Disease

AbstractPurpose of the Report In vivo tau PET imaging could help clarify the spatial distribution of tau deposition in Alzheimer disease (AD) and aid in the differential diagnosis of tauopathies. To date, there have been no in vivo 18F-APN1607 tau PET studies in patients with AD.Methods We applied tau tracer in 12 normal controls (NCs) and 10 patients in the mild to moderate stage of probable AD. Detailed clinical information, cognitive measurements, and disease severity were documented. Regional SUV ratios (SUVRs) from 18F-AV-45 (florbetapir), 18F-APN1607 PET images, and regional gray matter (GM) atrophic ratios were calculated for further analysis.Results Quantitative analyses showed significantly elevated SUVRs in the frontal, temporal, parietal, occipital lobes, anterior and posterior cingulate gyri, precuneus, and parahippocampal region (all P’s < 0.01) with medium to large effect sizes (0.44–0.75). The SUVRs from 18F-APN1607 PET imaging showed significant correlations with the Alzheimer’s Disease Assessment Scale (ADAS-cog) scores (all P’s < 0.01) and strong correlation coefficients (R2 ranged from 0.54 to 0.68), even adjusted for age and sex effects. Finally, the SUVRs from 18F-APN1607 PET imaging of the parahippocampal region showed rapid saturation as the ADAS-cog scores increased, and the SUVRs of the posterior cingulate gyrus and the temporal, frontal, parietal, and occipital regions slowly increased. The combined SUVRs from amyloid, tau PET, and regional GM atrophic ratio showed regional specific patterns as the ADAS-cog scores increased.Conclusions Our findings suggest that the 18F-APN1607 tau tracer correlated well with cognitive changes and demonstrated the spatial pattern of amyloid, tau deposition, and GM atrophy in the progression of AD

Insonation of Systemically Delivered Cisplatin-Loaded Microbubbles Significantly Attenuates Nephrotoxicity of Chemotherapy in Experimental Models of Head and Neck Cancer

The use of cisplatin (CDDP), the most common chemotherapy drug for head and neck cancer, is limited by its undesirable side effects, especially nephrotoxicity. We investigated ultrasound microbubbles (USMB) as a tool to increase the local intra-tumoral CDDP level while decreasing systemic CDDP cytotoxicity. We allowed CDDP to interact with human serum albumin and then sonicated the resulting CDDP‒albumin complex to generate CDDP-loaded MBs (CDDP-MBs). We then established a head-and-neck tumor-bearing mouse model by implanting FaDu-fLuc/GFP cells into severe combined immunodeficiency mice and used IVIS&reg; bioluminescence imaging to determine the tumor xenograft formation and size. Twice weekly (until Day 33), we administered CDDP only, CDDP + MBs + US, CDDP-MBs, or CDDP-MBs + US intravenously by tail-vein injection. The US treatment was administered at the tumor site immediately after injection. The in vivo systemic distribution of CDDP indicated that the kidney was the most vulnerable organ, followed by the liver, and then the inner ear. However, CDDP uptake into the kidney and liver was significantly decreased in both the CDDP-MBs and CDDP-MBs + US groups, suggesting that MB binding significantly reduced the systemic toxicity of CDDP. The CDDP-MBs + US treatment reduced the tumor size as effectively as conventional CDDP-only chemotherapy. Therefore, the combination of CDDP-MBs with ultrasound is effective and significantly attenuates CDDP-associated nephrotoxicity, indicating a promising clinical potential for this approach