Nanostructure-mediated drug delivery

Qiao

et al. 2011

Polym J

In this study, electrospun composite nanofibers containing nanoparticles for the programmable release of dual drugs were successfully fabricated through a one-step, single-nozzle electrospinning technique. Field-emission scanning electron microscopy and scanning electron microscopy were used to examine the morphology of the nanoparticles and electrospun nanofibers, respectively. The distribution of nanoparticles in the composite nanofibers was evaluated by fluorescence microscopy and laser scanning confocal microscopy. The results indicate that the nanoparticles were encapsulated within the composite nanofibers, forming a core-sheath structure. The different release behaviors of the drugs were ascribed to their varying distribution in the nanofibers and their interaction with carriers. A programmable release of both drugs was also achieved by adjusting the preparation process of the electrospinning solution. Composite nanofibers that can provide a platform for dual-drug loading and the programmed release of each drug may find application in drug delivery systems or in the tissue-engineering field.

Section: Resultsmentioning

confidence: 99%

Electrospun composite nanofibers containing nanoparticles for the programmable release of dual drugs

Qiao

et al. 2011

Polym J

“…Methanol (Merck, analytical grade, 99.5%), acetone (Ajax, NSW, Australia, analytical grade, 99.5%) and ethanol (Ajax, absolute, 100%) were used for etching and washing without further purification. N,N-dimethylformamide (DMF) was purified via standard laboratory protocols including drying over magnesium sulfate followed by distillation at reduced pressure [58] Ring-opening graft polymerization of PLLA Oxidized and silanized pSi films were soaked in 10 ml of toluene containing 5 µmol Sn(Oct) 2 catalyst for 1 h at 50°C before addition of 10 mmol (1.44 g) of recrystallized l-lactide. The polymerization reaction proceeded for 72 h at 110°C.…”

Section: Methodsmentioning

confidence: 99%

“…Hence, the development of new delivery systems is often considered as a commercially viable alternative to the expense of drug discovery and development [1][2][3]. Controlled drug delivery systems have now been developed to the point where they can facilitate site-specific delivery at precisely controlled rates [4][5][6][7][8][9].…”

mentioning

confidence: 99%

Controlled Drug Delivery From Composites of Nanostructured Porous Silicon and Poly( L -Lactide)

et al. 2012

Aims: Porous silicon (pSi) and poly(L-lactide) (PLLA) both display good biocompatibility and tunable degradation behavior, suggesting that composites of both materials are suitable candidates as biomaterials for localized drug delivery into the human body. The combination of a pliable and soft polymeric material with a hard inorganic porous material of high drug loading capacity may engender improved control over degradation and drug release profiles and be beneficial for the preparation of advanced drug delivery devices and biodegradable implants or scaffolds. Materials & methods: In this work, three different pSi and PLLA composite formats were prepared. The first format involved grafting PLLA from pSi films via surface-initiated ring-opening polymerization (pSi–PLLA [grafted]). The second format involved spin coating a PLLA solution onto oxidized pSi films (pSi–PLLA [spin-coated]) and the third format consisted of a melt-cast PLLA monolith containing dispersed pSi microparticles (pSi–PLLA [monoliths]). The surface characterization of these composites was performed via infrared spectroscopy, scanning electron microscopy, atomic force microscopy and water contact angle measurements. The composite materials were loaded with a model cytotoxic drug, camptothecin (CPT). Drug release from the composites was monitored via fluorimetry and the release profiles of CPT showed distinct characteristics for each of the composites studied. Results: In some cases, controlled CPT release was observed for more than 5 days. The PLLA spin coat on pSi and the PLLA monolith containing pSi microparticles both released a CPT payload in accordance with the Higuchi and Ritger–Peppas release models. Composite materials were also brought into contact with human lens epithelial cells to determine the extent of cytotoxicity. Conclusion: We observed that all the CPT containing materials were highly efficient at releasing bioactive CPT, based on the cytotoxicity data. Original submitted 16 December 2010; Revised submitted 29 September 2011; Published online 6 March 2012

“…As a consequence, an implicit assumption prevailing in the literature is that surface-engineering methods applied to improve soft-tissuecell cell adhesion (modification of surface chemistry, surface energy/wettability) can be likewise used to improve osteoblast adhesion to, and proliferation on, orthopedic biomaterials in vivo. In addition to these standard surface-engineering methods, precision engineering of surface topography is an alternative receiving considerable interest in orthopedic biomaterials because of the contemporaneity among nanoengineering, nanomedicine [103][104][105], and the demand for improved orthopedic healthcare mentioned in the Introduction. In principle, surface topography and surface chemistry can be varied independently but, in practice, this is difficult to do and even more difficult to prove that chemistry and topography are actually independent parameters.…”

Section: Influence Of Substratum Surface Chemistry/energy and Topogramentioning

confidence: 99%

Influence of substratum surface chemistry/energy and topography on the human fetal osteoblastic cell line hFOB 1.19: Phenotypic and genotypic responses observed in vitro☆

et al. 2007

Time-dependent phenotypic response of a model osteoblast cell line (hFOB 1.19, ATCC, CRL-11372) to substrata with varying surface chemistry and topography is reviewed within the context of extant cell-adhesion theory. Cell-attachment and proliferation kinetics are compared using morphology as a leading indicator of cell phenotype. Expression of (α 2 , α 3 , α 4 , α 5 , α v , β 1 and β 3 ) integrins, vinculin, as well as secretion of osteopontin and type I collagen supplement this visual assessment of hFOB growth. It is concluded that significant cell-adhesion events -contact, attachment, spreading, and proliferation -are similar on all surfaces, independent of substratum surface chemistry/energy. However, this sequence of events is significantly delayed and attenuated on hydrophobic (poorly water-wettable) surfaces exhibiting characteristically low-attachment efficiency and long induction periods before cells engage in an exponential-growth phase. Results suggest that a 'time-cell-substratum compatibility-superposition-principle' is at work wherein similar bioadhesive outcomes can be ultimately achieved on all surface types with varying hydrophilicity, but the time required to arrive at this outcome increases with decreasing cellsubstratum compatibility. Genomic and proteomic tools offer unprecedented opportunity to directly measure changes in the cellular machinery that lead to observed cell responses to different materials. But for the purpose of measuring structure-property relationships that can guide biomaterial development, genomic/proteomic tools should be applied early in the adhesion/spreading process before cells have an opportunity to significantly remodel the cell-substratum interface, effectively erasing cause-and-effect relationships between cell cell-substratum compatibility and substratum properties.Impact Statement-This review quantifies relationships among cell phenotype, substratum surface chemistry/energy, topography, and cell-substratum contact time for the model osteoblast cell